Steap2 directed t-cell engagers and compositions thereof

Abstract

Provided are T cell engaging molecules that bind an antigen on a non-immune cell and an antigen on an immune cell. The T cell engaging molecules can bind STEAP2 on a cancer cell and, e.g., a CD3 on a T cell. The T cell engaging molecules can also bind STEAP2 on a cancer cell and, e.g., a CD8 on a T cell. Alternatively, the T cell engaging molecules can bind STEAP2 on a cancer cell and both CD3 and CD8 on a T cell.

Description

STEAP2 DIRECTED T-CELL ENGAGERS AND COMPOSITIONS THEREOFCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 495,547, filed April 11, 2023, which is incorporated herein by reference in its entirety.REFERENCE TO SEQUENCE LISTING SUBMITTED ELECTRONICALLY

[0002] The content of the electronically submitted sequence listing (Name: STEAP2TED- 100-WO-PCT_ST26.xml; Size: 182,496 bytes; and Date of Creation: April 10, 2024), filed with the application, is incorporated herein by reference in its entirety.BACKGROUND

[0003] Multivalent binding molecules, which recognize two or more different epitopes, are of interest in diagnostic and therapeutic approaches. However, their generation presents challenges. Promiscuous pairing of heavy and light chains expressed in one cell can result in the production of several different molecules, with only one pairing being the desired one and the remaining pairings resulting in non-functional or monospecific molecules.

[0004] Various strategies have been developed in an attempt to overcome this problem and encourage the correct assembly of the desired multivalent molecule. However, with the introduction of each further binding arm the possibility for mispairings increases.

[0005] Therefore, there is a need for additional mechanisms to improve pairing of polypeptide chains in multivalent molecules and facilitate their efficient production.BRIEF SUMMARY

[0006] Provided is a T cell engaging molecule comprising: (a) an antigen binding arm that binds an epitope on human six transmembrane epithelial antigen of prostate-2 (STEAP2) and comprises a heavy chain comprising a heavy chain variable domain (VH) comprising a variableheavy chain complementarity determining region 1 (VH-CDR1) selected from SEQ ID NOs: 1, 9, 17, 103, 111, 127, 135, and 143; a VH-CDR2 selected from SEQ ID NOs: 2, 10, 18, 104, 112, 128, 136, and 144; a VH-CDR3 selected from SEQ ID NOs: 3, 11, 19, 94, 96, 98, 105, 113, 129, 137, and 145; a heavy chain CHI domain; and a light chain comprising a light chain variable domain (VL) comprising a variable light chain complementarity determining region 1 (VL-CDR1) selected from SEQ ID NOs: 4, 12, 20, 100, 108, 130, 138, and 146; a VL-CDR2 selected from SEQ ID NOs: 5, 13, 21, 101, 109, 131, 139, and 147; a VL-CDR3 selected from SEQ ID NOs: 6, 14, 22, 102, 110, 132, 140, and 148; and a light chain constant domain; (b) a first T cell binding arm comprising a heavy chain comprising a heavy chain variable domain (VH) comprising a VH- CDR1 selected from SEQ ID NOs: 36, 40, and 44; a VH-CDR2 selected from SEQ ID NOs: 37, 41, and 45; a VH-CDR3 selected from SEQ ID NOs: 38, 42, and 46; and a heavy chain CHI domain; and a light chain comprising a light chain variable domain (VL) comprising a VL-CDR1 selected from SEQ ID NOs: 27 and 31; a VL-CDR2 selected from SEQ ID NOs: 28 and 32; a VL- CDR3 selected from SEQ ID NOs: 29 and 33; and a light chain constant domain; and (c) an Fc domain comprising a first Fc region and a second Fc region, each Fc region comprising a CH2 domain and a CH3 domain; said Fc domain further comprising at least one modification to promote heterodimerization.

[0007] In some aspects, provided is a trivalent T cell engaging molecule comprising the T cell engaging molecule as described and further comprising (d) a second T cell binding arm that binds to cluster of differentiation 8 (CD8) and comprises a heavy chain comprising a heavy chain variable domain (VH) comprising a VH-CDR1 set forth in SEQ ID NO: 48, a VH-CDR2 set forth in SEQ ID NO: 49, and a VH-CDR3 set forth in SEQ ID NO: 50, and a heavy chain CHI domain; and a light chain comprising a light chain variable domain (VL) comprising a VL-CDR1 set forth in SEQ ID NO: 51, a VL-CDR2 set forth in SEQ ID NO: 52, and a VL-CDR3 set forth in SEQ ID NO: 53, and a light chain constant domain.

[0008] In some aspects, the heavy chain of the second T cell binding arm is attached to the heavy chain of the first T cell binding arm through a linker.

[0009] In some aspects, the heavy chain of the second T cell binding arm is attached to the heavy chain of the antigen binding arm through a linker.

[0010] In some aspects, the linker comprises the amino acid sequence of SEQ ID NO: 89.

[0011] In some aspects, the linker comprises from 1 to about 10 copies of SEQ ID NO: 89.

[0012] In some aspects, the linker comprises 2 copies of SEQ ID NO: 89.

[0013] In some aspects, one of the two CH3 domains of the T cell engaging molecule or trivalent T cell engaging molecule comprises a knob mutation, and the other of the two CH3 domain comprises a hole mutation.

[0014] In some aspects, the CHI domain and the light chain constant domain of one or more of each of the (a) antigen binding arm, (b) the first T cell binding arm, and (d) the second T cell binding arm further comprises a charge pair substitution comprising a first charged amino acid substitution in the CHI domain and a second charged amino acid substitution in the light chain constant domain, wherein the first charged amino acid substitution and the second charged amino acid substitution have an opposite charge.

[0015] In some aspects, the light chain constant domain of one or more of each of (a), (b), and (d) of the T cell engaging molecule or trivalent T cell engaging molecule is a lambda light chain constant domain (CLX) and wherein the charge pair is a lambda charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine, wherein the numbering is according to the EU index and wherein the charged amino acids of the lambda charge pair are located at one or more of the following positions:(i) position 117 in the CLA. and position 141 in the CHI domain;(ii) position 117 in the CLA and position 185 in the CHI domain;(iii) position 119 in the CEL and position 128 in the CHI domain;(iv) position 134 in the CLA. and position 128 in the CHI domain;(v) position 134 in the CLA. and position 145 in the CHI domain;(vi) position 134 in the CLA. and position 183 in the CHI domain;(vii) position 136 in the CLA. and position 185 in the CHI domain;(viii) position 178 in the CLA. and position 173 in the CHI domain; and / or(ix) position 117 in the CLA. and position 187 in the CHI domain.

[0016] In some aspects, the charged amino acids of the lambda charge pair of the T cell engaging molecule or trivalent T cell engaging molecule are as follows:(i) the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is arginine and the chargedamino acid at position 141 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is threonine;(ii) the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is threonine;(iii) the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is threonine;(iv) the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid atposition 134 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is threonine;(v) the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is threonine;(vi) the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is threonine;(vii) the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is threonine;(viii) the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is arginine and the charged amino acidat position 173 is glutamic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is serine; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is threonine; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is serine; or the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is threonine; and / or (ix) the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is threonine.

[0017] In some aspects, the light chain constant domain of one or more of each of (a), (b), and (d) is a kappa light chain constant domain (CLK) and wherein the charge pair is a kappa charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine, wherein the numbering is according to the EU index and wherein the kappa charge pair is located at position 133 in the CLK and position 183 in the CHI domain.

[0018] In some aspects, the charged amino acids of the kappa charge pair of the T cell engaging molecule or trivalent T cell engaging molecule are as follows: (i) the charged amino acid at position 133 is glutamic acid and the charged amino acid at position 183 is lysine; or (ii) the charged amino acid at position 133 is lysine and the charged amino acid at position 183 is glutamic acid.

[0019] In some aspects, the light chain constant domain of one of (a), (b), and (d) is a CLX and wherein the charge pair is a lambda charge pair and the light chain constant domain of a second and a third of (a), (b), and (d) is a CLX or a CLK and wherein the charge pair is a lambda or a kappacharge pair and the second of (a), (b), and (d) comprises a charged amino acid in the CHI domain of a same charge as a charged amino acid in the CHI domain of the third of (a), (b), and (d).

[0020] In some aspects, the light chain constant domain of one of (a), (b), and (d) is a CLX. and wherein the charge pair is a lambda charge pair and the light chain constant domain of a second and a third of (a), (b), and (d) is a CLK and wherein the charge pair is a kappa charge pair and the second of (a), (b), and (d) comprises a charged amino acid in the CHI domain of a same charge as a charged amino acid in the CHI domain of the third of (a), (b), and (d).

[0021] In some aspects, the CHI domain of (a), (b), and / or (d) of the T cell engaging molecule or trivalent T cell engaging molecule is capable of being linked to the light chain constant domain through an engineered disulfide link.

[0022] In some aspects, the CHI domain of (b) and (d) of the T cell engaging molecule or trivalent T cell engaging molecule is capable of being linked to the light chain constant domain through an engineered disulfide link and the CHI domain of (a) is linked to the light chain constant domain through a native disulfide link.

[0023] In some aspects, the CHI domain of the T cell engaging molecule or trivalent T cell engaging molecule that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid,(ii) a substitution of a native non-cysteine amino acid to a cysteine; and the light chain constant domain comprises(i) a substitution of a native cysteine to a non-cysteine amino acid,(ii) a substitution of a native non-cysteine amino acid to a cysteine; and wherein the substituted cysteine of the light chain constant domain and the substituted cysteine of the CHI domain can form a disulfide bond.

[0024] In some aspects, the CHI domain of the T cell engaging molecule or trivalent T cell engaging molecule that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 220,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 126; and the light chain constant domain comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 212,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 122, wherein the cysteine at position 126 of the CHI domain and the cysteine at position 122 of the light chain constant domain can form a disulfide bond; wherein the numbering is according to the EU index.

[0025] In some aspects, the CHI domain of the T cell engaging molecule or trivalent T cell engaging molecule that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 220,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 126; and the light chain constant domain comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 214,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 121, wherein the cysteine at position 126 of the CHldomain and the cysteine at position 121 of the light chain constant domain can form a disulfide bond; wherein the numbering is according to the EU index.

[0026] In some aspects, the antigen binding arm of the T cell engaging molecule or trivalent T cell engaging molecule comprises a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 7, 15, 23, 93, 95, 97, 106, 114, 133, 141, and 149.

[0027] In some aspects, the antigen binding arm of the T cell engaging molecule or trivalent T cell engaging molecule is attached to the Fc domain and comprises a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 66, 67, 69, 72, 73, and 76.

[0028] In some aspects, the antigen binding arm of the T cell engaging molecule or trivalent T cell engaging molecule comprises a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 8, 16, 24, 107, 115, 134, 142, and 150.

[0029] In some aspects, the antigen binding arm of the T cell engaging molecule or trivalent T cell engaging molecule comprises a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NOs: 63.

[0030] In some aspects, the VL of the T cell binding arm of the T cell engaging molecule or the VL of the first or second T cell binding arm of the trivalent T cell engaging molecule comprises a VL-CDR1 selected from SEQ ID NOs: 27 and 31; a VL-CDR2 selected from SEQ ID NOs: 28 and 32; and a VL-CDR3 selected from SEQ ID NOs: 29 and 33; and the VH comprises a VH-CDR1 selected from SEQ ID NOs: 36, 40, and 44; a VH-CDR2 selected from SEQ ID NOs: 37, 41 and 45; and a VH-CDR3 selected from SEQ ID NOs: 38, 42, and 46.

[0031] In some aspects, the VL of the T cell binding arm of the T cell engaging molecule or the VL of the first or second T cell binding arm of the trivalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30 or 34.

[0032] In some aspects, the light chain constant domain of the T cell engaging molecule or the light chain constant domain of the first or second T cell binding arm of the trivalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 60 or 61.

[0033] In some aspects, the VH of the T cell binding arm of the T cell engaging molecule or the VH of the first or second T cell binding arm of the trivalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NOs: 39, 43, or 47.

[0034] In some aspects, the heavy chain of the T cell binding arm of the T cell engaging molecule or the first or second T cell binding arm of the trivalent T cell engaging molecule is attached to the Fc domain and comprises a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, atleast about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 74, 75, 77, 78, and 79.

[0035] In some aspects, the VH of the second T cell binding arm of the trivalent T cell engaging molecule comprises a VH-CDR1 set forth in SEQ ID NO: 48; a VH-CDR2 set forth in SEQ ID NO: 49; a VH-CDR3 set forth in SEQ ID NO: 50; and the VL comprises a VL-CDR1 set forth in SEQ ID NO: 51; a VL-CDR2 set forth in SEQ ID NO: 52; and a VL-CDR3 set forth in SEQ ID NO: 53.

[0036] In some aspects, the VL of the second T cell binding arm of the trivalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 54.

[0037] In some aspects, the constant light chain domain of the second T cell binding arm of the trivalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 64.

[0038] In some aspects, the VH of the second T cell binding arm of the trivalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 56.

[0039] In some aspects, the CHI domain of the second T cell binding arm of the trivalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NO: 57, 66, 67, 69, 74, 75, 77, 78, and 79.

[0040] In some aspects, the antigen binding arm of the T cell engaging molecule or trivalent T cell engaging molecule binds an epitope on an extracellular loop of STEAP2.

[0041] In some aspects, the T cell engaging molecule comprises SEQ ID NOs: 25, 26, 35, 81, and 92. In some aspects, the trivalent T cell engaging molecule comprises SEQ ID NOs: 25, 26, 35, 55 and 58.

[0042] In some aspects, provided is a trivalent T cell engaging molecule comprising: (a) a first antigen binding arm and a second antigen binding arm that each bind an epitope on human six transmembrane epithelial antigen of prostate-2 (STEAP2) and each comprise a heavy chain comprising a heavy chain variable domain (VH) comprising a variable heavy chain complementarity determining region 1 (VH-CDR1) selected from SEQ ID NOs: 1, 9, 17, 103, 111, 127, 135, and 143; a VH-CDR2 selected from SEQ ID NOs: 2, 10, 18, 104, 112, 128, 136, and 144; a VH-CDR3 selected from SEQ ID NOs: 3, 11, 19, 94, 96, 98, 105, 113, 129, 137, and 145; a heavy chain CHI domain; and a light chain comprising a light chain variable domain (VL) comprising a variable light chain complementarity determining region 1 (VL-CDR1) selected from SEQ ID NOs: 4, 12, 20, 100, 108, 130, 138, and 146; a VL-CDR2 selected from SEQ ID NOs: 5, 13, and 21; a VL-CDR3 selected from SEQ ID NOs: 6, 14, 22, 102, 110, 132, 140, and 148; and a light chain constant domain; (b) a first T cell binding arm that binds to cluster of differentiation 3 (CD3) and comprises a heavy chain comprising a VH comprising a VH-CDR1 selected from SEQ ID NOs: 36, 40, and 44; a VH-CDR2 selected from SEQ ID NOs: 37, 41, and 45; a VH-CDR3 selected from SEQ ID NOs: 38, 42, and 46; and a heavy chain CHI domain; and a light chain comprising a VL comprising a VL-CDR1 selected from SEQ ID NOs: 27 and 31; a VL-CDR2 selected from SEQ ID NOs: 28 and 32; a VL-CDR3 selected from SEQ ID NOs: 29 and 33; and a light chain constant domain; and (c) an Fc domain comprising a first Fc region and a second Fc region, each Fc region comprising a CH2 domain and a CH3 domain, and further comprising at least one modification to promote heterodimerization; and wherein the heavy chain of the first antigen binding arm and the heavy chain of the first T cell binding arm are attached to the Fc domain, and the heavy chain of the second antigen binding arm is attached to the heavy chain of the first T cell binding arm.

[0043] In some aspects, provided is a tetravalent T cell engaging molecule comprising the trivalent T cell engaging molecule described above and further comprising (d) a second T cell binding arm that binds to cluster of differentiation 8 (CD8) and comprises a heavy chain comprising a variable heavy domain (VHH) comprising a VH-CDR1 set forth in SEQ ID NO: 84; a VH-CDR2 set forth in SEQ ID NO: 85; and a VH-CDR3 set forth in SEQ ID NO: 86.

[0044] In some aspects, the heavy chain of the second T cell binding arm of the tetravalent T cell engaging molecule is attached to the heavy chain of the first antigen binding arm.

[0045] In some aspects, the heavy chain of the second antigen binding arm of the trivalent or tetravalent T cell engaging molecule is attached to the heavy chain of the first T cell binding arm through a linker.

[0046] In some aspects, the heavy chain of the second T cell binding arm of the tetravalent T cell engaging molecule is attached to the heavy chain of the first antigen binding arm through a linker.

[0047] In some aspects, the linker comprises the amino acid sequence of SEQ ID NO: 89.

[0048] In some aspects, the linker comprises from 1 to about 10 copies of SEQ ID NO: 89.

[0049] In some aspects, the linker comprises 2 copies of SEQ ID NO: 89.

[0050] In some aspects, one of the two CH3 domains of the trivalent or tetravalent T cell engaging molecule comprises a knob mutation, and the other of the two CH3 domain comprises a hole mutation.

[0051] In some aspects, the CHI domain and the light chain constant domain of one or more of each of the (a) first antigen binding arm or second antigen binding arm, and (b) the first T cell binding arm, comprises a charge pair substitution comprising a first charged amino acid substitution in the CHI domain and a second charged amino acid substitution in the light chain constant domain, wherein the first charged amino acid substitution and the second charged amino acid substitution have an opposite charge.

[0052] In some aspects, the light chain constant domain of one or more of each of (a) the first antigen binding arm or the second antigen binding arm, and (b) the first T cell binding arm is a lambda light chain constant domain (CLX) and the charge pair is a lambda charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine, wherein the numbering is according to the EU index and wherein the lambda charge pair is located at one or more of the following positions:(i) position 117 in the CLA. and position 141 in the CHI domain;(ii) position 117 in the CLA and position 185 in the CHI domain;(iii) position 119 in the CEL and position 128 in the CHI domain;(iv) position 134 in the CLA. and position 128 in the CHI domain;(v) position 134 in the CLX. and position 145 in the CHI domain;(vi) position 134 in the CLX and position 183 in the CHI domain;(vii) position 136 in the CLX and position 185 in the CHI domain;(viii) position 178 in the CLX and position 173 in the CHI domain; and(ix) position 117 in the CLX and position 187 in the CHI domain.

[0053] In some aspects, the charged amino acids of the lambda charge pair of the trivalent or tetravalent T cell engaging molecule are as follows:(i) the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is threonine;(ii) the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is threonine;(iii) the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is threonine;(iv) the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is threonine;(v) the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is threonine;(vi) the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is threonine;(vii) the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is threonine;(viii) the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is serine; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is threonine; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is serine; or the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is threonine; and / or(ix) the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is threonine.

[0054] In some aspects, the light chain constant domain of one or more of each of (a) the first antigen binding arm or the second antigen binding arm, and (b) the first T cell binding arm is a kappa light chain constant domain (CLK) and the charge pair is a kappa charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and a negativelycharged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine, wherein the numbering is according to the EU index and wherein the kappa charge pair is located at position 133 in the CLK and position 183 in the CHI.

[0055] In some aspects, the charged amino acids of the kappa charge pair of the trivalent or tetravalent T cell engaging molecule are as follows: (i) the charged amino acid at position 133 is glutamic acid and the charged amino acid at position 183 is lysine; or (ii) the charged amino acid at position 133 is lysine and the charge amino acid at position 183 is glutamic acid.

[0056] In some aspects, the light chain constant domain of one of (a), (b), and (d) is a CLX and wherein the charge pair is a lambda charge pair and the light chain constant domain of a second and a third of (a), (b), and (d) is a CLX or CLK and wherein the charge pair is a lambda or a kappa charge pair and the second of (a), (b), and (d) comprises a charged amino acid in the CHI domain of a same charge as a charged amino acid in the CHI domain of the third of (a), (b), and (d).

[0057] In some aspects, the light chain constant domain of one of (a), (b), and (d) is a CLX and wherein the charge pair is a lambda charge pair and the light chain constant domain of a second and a third of (a), (b), and (d) is a CLK and wherein the charge pair is a kappa charge pair and the second of (a), (b), and (d) comprises a charged amino acid in the CHI domain of a same charge as a charged amino acid in the CHI domain of the third of (a), (b), and (d).

[0058] In some aspects, the CHI domain of (a) and / or (b) of the trivalent T cell engaging molecule or the CHI domain of (a), (b), and / or (d) of the tetravalent T cell engaging molecules is capable of forming a disulfide link to the light chain constant domain of (a) and / or (b) of the trivalent T cell engaging molecule or the light chain of (a), (b), and / or (d) of the tetravalent T cell engaging molecule through an engineered disulfide link.

[0059] In some aspects, the CHI domain of (b) of the trivalent or tetravalent T cell engaging molecule is capable of forming a disulfide link to the light chain constant domain through an engineered disulfide link and the CHI domain of (a) is linked to the light chain constant domain through a native disulfide link.

[0060] In some aspects, CHI domain of (b) and (d) of the tetravalent T cell engaging molecule are capable of forming a disulfide link to the light chain constant domain of (b) and (d) through an engineered disulfide link and the CHI domain of (a) is linked to the light chain constant domain of (a) through a native disulfide link.

[0061] In some aspects, the CHI domain of the first T cell binding arm of the trivalent or tetravalent T cell engaging molecule comprises(i) a substitution of a native cysteine to a non-cysteine amino acid,(ii) a substitution of a native non-cysteine amino acid to a cysteine; and the light chain constant domain of the second T cell binding arm comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid,(ii) a substitution of a native non-cysteine amino acid to a cysteine; wherein the substituted cysteine of the CHI domain of the first T cell binding arm and the substituted cysteine of the light chain constant domain of the first T cell binding arm can form a disulfide bond.

[0062] In some aspects, the CHI domain of the first T cell binding arm of the trivalent or tetravalent T cell engaging molecule comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 220,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 126; and the light chain constant domain comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 212,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 122, wherein the cysteine at position 126 of the CHI domain and the cysteine at position 122 of the light chain constant domain can form a disulfide bond; wherein the numbering is according to the EU index.

[0063] In some aspects, the light chains of the first and second antigen binding arms of the trivalent or tetravalent T cell engaging molecule comprise a native cysteine and the CHI domain of the first and second antigen binding arms comprise a native cysteine, wherein the native cysteine of the CHI domain of the first antigen binding arm and the native cysteine of the light chain constant domain of the first antigen binding arm can form a disulfide bond and the native cysteine of the CHI of the second antigen binding arm and the native cysteine of the light chain constant domain of the second antigen binding arm can form a disulfide bond.

[0064] In some aspects, the VH of the first antigen binding arm of the trivalent or tetravalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%,at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149.

[0065] In some aspects, the CHI of the first antigen binding arm of the trivalent or tetravalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NO: 67 and 93.

[0066] In some aspects, the VL of the first antigen binding arm of the trivalent or tetravalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 8, 16, 24, 107, 115, 134, 142, and 150.

[0067] In some aspects, the light chain constant domain of the first antigen binding arm of the trivalent or tetravalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 63.

[0068] In some aspects, the VL of the first T cell binding arm of the trivalent or tetravalent T cell engaging molecule comprises a VL-CDR1 set forth in SEQ ID NO: 27 or 31; a VL-CDR2 set forth in SEQ ID NO: 28 or 32; a VL-CDR3 set forth in SEQ ID NO: 29 or 33; and the VH of the first T cell binding arm comprises a VH-CDR1 set forth in SEQ ID NO: 36, 40, or 44; a VH- CDR2 set forth in SEQ ID NO: 37, 41 or 45; and a VH-CDR3 set forth in SEQ ID NO: 38, 42, or 46.

[0069] In some aspects, the VL of the first T cell binding arm of the trivalent or tetravalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30 or 34.

[0070] In some aspects, the VH of the first T cell binding arm of the trivalent or tetravalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at leastabout 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 39, 43, and 47.

[0071] In some aspects, the VH of the second T cell binding arm of the tetravalent T cell engaging molecule comprises a VH-CDR1 set forth in SEQ ID NO: 84; a VH-CDR2 set forth in SEQ ID NO: 85; and a VH-CDR3 set forth in SEQ ID NO: 86.

[0072] In some aspects, the VH of the second T cell binding arm of the tetravalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 56 or 83.

[0073] In some aspects, a tetravalent T cell engaging molecule comprising the trivalent T cell engaging molecule further comprises (d) a second T cell binding arm. In some aspects, the second T cell binding arm comprises a VL comprising a VL-CDR1 set forth in SEQ ID NO: 51; a VL-CDR2 set forth in SEQ ID NO: 52; and a VL-CDR3 set forth in SEQ ID NO: 53, and a VH comprising a VH-CDR1 set forth in SEQ ID NO: 48; a VH-CDR2 set forth in SEQ ID NO: 49; and a VH-CDR3 set forth in SEQ ID NO: 50. In some aspects, the VL of the second T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 54, and wherein the VH of the second T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 56. In some aspects, the trivalent or tetravalent T cell engaging molecule binds an epitope on an extracellular loop of STEAP2.

[0074] In some aspects, the trivalent or tetravalent T cell engaging molecule comprises a heavy chain comprising the heavy chain constant region of the second antigen binding arm and the first T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 81. In some aspects, the heavy chain comprising the heavy chain constant region of the first antigen binding arm and the second T cell binding arm comprises an amino acid sequence havingat least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NO: 87. In some aspects, the trivalent T cell engaging molecule comprises SEQ ID NO: 25, 35, 81, 25, and 93. In some aspects, the tetravalent T cell engaging molecule comprises SEQ ID NOs: 25, 35, 81, 25, and 87. In some aspects, the tetravalent T cell engaging molecule comprises SEQ ID NOs: 151, 152, 153, 154, and 152. In some aspects, the tetravalent T cell engaging molecule comprises SEQ ID NO: 151, two copies of SEQ ID NO: 152, SEQ ID NO: 153, and SEQ ID NO: 154.

[0075] In some aspects, the T cell engaging molecule is encoded by one or more nucleic acid(s). In some aspects, a vector comprises the nucleic acid(s). In some aspects, an isolated host cell comprises the nucleic acid(s) or the vector. In other aspects, the T cell engaging molecule is formulated with a pharmaceutically acceptable carrier. The present disclosure also concerns the treatment of disease. In some aspects, the disclosure concerns a method of treating a disease in a patient in need thereof, the method comprising administering to the patient an effective amount of the T cell engaging molecule. In some aspects, the disease is cancer. In some aspects, the disease is prostate cancer. In some aspects, the T cell engaging molecule is formulated for use as a medicament. In some aspects, the T cell engaging molecule is for use in the treatment of cancer. In some aspects, the T cell engaging molecule is used in the manufacture of a medicament for the treatment of cancer.BRIEF DESCRIPTION OF THE DRAWINGS / FIGURES

[0076] Figure 1A shows a schematic of a T cell engaging molecule (TED). Figure IB shows a schematic of a T cell engaging molecule (TED2). Figure 1C shows a schematic of a trivalent T cell engaging molecule (TED3). Figure ID shows a schematic of a tetravalent T cell engaging molecule (TED4).

[0077] Figure 2 shows a ribbon diagram of a kappa and a CHI chain interacting surface of a binding arm of a T cell engager.

[0078] Figure 3 shows a ribbon diagram of a lambda and a CHI chain interacting surface of a binding arm of a T cell engager.

[0079] Figure 4A shows binding of trivalent STEAP2 T cell engager molecules TED3 30D12 G96P / CD3 K29-SN75_3 and TED3 30D12 G96P / CD3 K29-SN75_V12 to C4-2 cells compared to TED3 Nip228_V12 controls. Figure 4B shows CD8 binding of STEAP2 trivalent T cell engaging molecules TED3 30D12 G96P / CD3 K29-SN75 3 and TED3 30D12 G96P / CD3 K29-SN75_V12. Figure 4C shows binding of tetravalent STEAP2 T cell engager molecule 40A3LO12-TED4-K17 / E75 to C4-2 cells. Figure 4D shows CD8 binding of STEAP2 tetravalent T cell engaging molecule 40A3LO12-TED4-K17 / E7. Figure 4E shows cytotoxicity of STEAP2 trivalent T cell engager molecules 30D12-TED3 K29 / SN75 and 30D12-TED3 K29 / SN75 V12 compared to 30D12-TED3-control-CD3, 30D12-TED3-control-CD3 VI 2, and TED3 NIP228 / control-CD3 / CD8 V12 controls. Figure 4F shows CD8+ T cell activation by trivalent STEAP2 T cell engaging molecules 30D12-TED3 K29 / SN75 and 30D12-TED3 K29 / SN75 V12 compared to 30D12-TED3-control-CD3, 30D12-TED3-control-CD3 VI 2, and TED3 NIP228 / control-CD3 / CD8 V12 controls. Figure 4G shows CD4+ T cell activation by trivalent STEAP2 T cell engaging molecules 30D12-TED3 K29 / SN75 and 30D12-TED3 K29 / SN75 V12 compared to 30D12-TED3 control-CD3, 30D12-TED3 control-CD3 VI 2, and TED3 NIP228 / control-CD3 / CD8 V12 controls. Figure 4H shows STEAP2 T cell engaging molecule 40A3LO12-TED2-K29 / SN75 demonstrated high cytotoxicity against high STEAP2 expressing cells LNCap, C4-2, VCaP, 22Rvl cells and low cytotoxicity against low STEAP2 expressing DU145 cells n. Figure 41 shows trivalent STEAP2 T cell engaging molecule 30D12-TED3- K29 / SN75 demonstrated high cytotoxicity against high STEAP2 expressing cells LNCap, C4-2, VCaP, 22Rvl cells and low cytotoxicity against low STEAP2 expressing DU145 cells. Figure 4J shows the EC50 of the STEAP2 T cell engaging moleculs and the trivalent STEAP2 T cell engaging molecule in cell lines with different levels of STEAP2 expression. Figure 4K shows STEAP2 receptor density on different cell lines. Figure 4L shows cytotoxicity and IL-6 and TNFa cytokine release induced by STEAP2 T cell engaging molecule 40A3LO12-TED2- K29 / SN75 and trivalent STEAP2 T cell engaging molecule 30D12-TED3-K29 / SN75 in LNCaP, C4-2 and VCaP cell lines.

[0080] Figure 5A shows activation of CD4 and CD8 T cells by a STEAP2 T cell engaging molecule (TED) and a trivalent (TED3) STEAP2 CD8-guided T cell engaging molecule. Figure 5B shows T-cell activation by a bivalent STEAP2 T cell engaging molecule (TED2) and various tetravalent (TED4) STEAP2 CD8-guided T cell engaging molecules.Figure 5C shows that 30D12-TED3-K29 / SN75 triggered reduced IL-6 release compared to 30D12-TED-K29 / SN75 molecule at similar levels of cytotoxicity. Figure 5D shows lower levels of IL-6 release were also observed for all variants of TED4 T cell engagers at similar levels of cytotoxicity compared to 40A3LO12-TED2-K29 / SN75.

[0081] Figure 6A shows the percent suppression of cytolysis at different Treg to T effector cell ratios by TED2 T cell engaging molecule and a TED3 trivalent STEAP2 T cell engaging molecule. Figure 6B shows Treg activation of untreated cells and cells treated with a T cell engaging molecule (TED) and a trivalent (TED3) STEAP2 CD8-guided T cell engaging molecule.

[0082] Figure 7A shows fluorescence of mKate-labeled C4-2 spheroid tumors over time in the absence (control) and presence of trivalent STEAP2 T cell engaging molecules (TED3) at increasing concentrations. Figure 7B showed tumor cell killing of the mKate2-expressing C4-2 spheroids by PBMCs was also observed with all variants of TED4 T cell engagers and was increased compared to 40A3LO12-TED2-K29 / SN75.

[0083] Figure 8A shows tumor volume in human PBMC engrafted mice implanted with LNCaP tumor cells and either untreated or treated with untargeted trivalent T cell engaging molecules (NIP228-TED3-K29 / SN75 V12) or trivalent (30D12-TED3-K29 / SN75 V12) STEAP2 CD8-guided T cell engager molecules . Figure 8B shows tumor volume in human PBMC engrafted mice implanted with C4-2 tumor cells and either untreated or treated with TED2 T cell engaging molecule or trivalent STEAP2 CD8-guided T cell engaging molecules. Figure 8C shows bioluminescence images of mice engrafted with human PBMC and i.v. injected with luciferase-expressing C4-2 tumor cells and either untreated (PBS) or treated with trivalent STEAP2 CD8-guided T cell engaging molecules. Figure 8D shows a graph of the bioluminescence of the mice in Figure 8C.

[0084] Figure 9 shows TNF-a levels in mice implanted with luciferase-expressing C4-2 tumor cells, and engrafted with human PBMC from two different donors and either untreated (PBS) or treated with STEAP2 T cell engaging molecules with a CD3 control binding arm (30D12-TED-CD3 control), STEAP2 T cell engaging molecules with a modified CD3 binding arm (30D12-TED-KN29 / SN75), or trivalent STEAP2 CD8-guided T cell engaging molecules with a modified CD3 binding arm (30D12-TED3-K29 / SN75 V12).

[0085] Figure 10 shows tumor volume in mice subcutaneously implanted with a mix of human PBMCs and C4-2 tumor cells and either untreated (PBS) or treated with 40A3LO12- TED2-K29 / SN75 or 30D12-TED3-K29 / SN75 V12 molecules.

[0086]

[0087] Figure 11 shows tumor volume in human immune stem cell-engrafted mice subcutaneously implanted with C4-2 tumor cells and either untreated or treated with 30D12- TED3-K29 / SN75 V12 molecules. Figure 12 shows the correlation between EC50 of cytolysis of tetraval ent STEAP2 T cell engaging molecule 40A3LO12-TED4-K17 / E75 and level of STEAP2 cell surface expression (antigen binding capacity, ABC) across 8 tumor cell lines.

[0088] Figure 13 shows that addition of regulatory T cells (Treg) into co-cultures of effector T cells and tumor cells reduces granzyme B production in CD8 T cells in response to a non-CD8-guided T cell engaging molecule but no impact of Tregs in seen in response to CD8- guided 40A3LO12-TED4-K17 / E75.

[0089] Figure 14 shows sustained cytotoxicity of PBMCs after up to 4 rounds of coculture with tumor cells in the presence of 40A3LO12-TED4-K17 / E75.

[0090] Figure 15 shows cytotoxicity of STEAP2-negative cells occurs only when cocultured with various amounts of STEAP2-positive cells.

[0091] Figure 16A and B show cytotoxicity of a prostate cancer patient-derived xenograft organoid when co-cultured with T cells in the presence of 40A3LO12-TED4-K17 / E75. No cytotoxicity was observed in response to an untargeted NIP228-TED4-K17 / E75 molecule. Figure 16C shows increased activation of CD8+ T cells compared to CD4+ T cells at the end of this assay.

[0092] Figure 17 shows increased IFNg release in primary prostate tumour slices treated with 40A3LO12-TED4-K17 / E75.

[0093] Figure 18A shows tumor volume in human PBMC engrafted mice implanted with 22Rvl tumor cells and either untreated or treated with untargeted T cell engaging molecules (NIP228-TED4-K17 / E75) or tetravalent (40A3LO12-TED4-K17 / E75) STEAP2 CD8-guided T cell engager molecules. Figure 18B shows unchanged levels of CD69 and CD25 on T cells in the blood of these animals after receiving 3 doses of 40A3LO12-TED4-K17 / E75. Figure 18C shows increased levels of CD69 and CD25 on CD8+ T cells but not CD4+ T cells in the tumour of these animals after receiving 3 doses of 40A3LO12-TED4-K17 / E75.

[0094] Figure 19 shows tumor burden (as measured by bioluminescent imaging) in human PBMC engrafted mice implanted intratibially with luciferase-expressing C4-2 tumor cells and either untreated or treated with untargeted T cell engaging molecules (NIP228-TED4- K17 / E75) or tetravalent (40A3LO12-TED4-K17 / E75) STEAP2 CD8-guided T cell engager molecules.

[0095] Figure 20 shows tumor volume in human PBMC engrafted mice implanted with fragments of a prostate cancer patient-derived xenograft model and either untreated or treated with tetravalent (40A3LO12-TED4-K17 / E75) STEAP2 CD8-guided T cell engager molecules.DETAILED DESCRIPTION

[0096] Provided are T cell engaging molecules that bind an antigen on a target cell, e.g., human six transmembrane epithelial antigen of prostate-2 (STEAP2) on a cancer cell, and a T cell antigen, e.g., a cluster of differentiation 3 (CD3) and / or CD8 protein. Further provided are methods of making and using the T cell engaging molecules. In some aspects, the T cell engaging molecules bind one or more antigens, e.g. one or more epitopes on a STEAP2 of a cancer cell, and one or more T cell proteins, e.g., a CD3 and / or CD8. Without wanting to be bound by theory, it is hypothesized that the number and efficacy of target protein and T cell interactions afforded by the T cell engaging molecules described herein enables an increase in target cell killing while reducing the risk of inducing a cytokine release syndrome. i. Definitions

[0097] In order that the present description can be more readily understood, certain terms are first defined. Additional definitions are set forth throughout the detailed description.

[0098] It is to be noted that the term “a” or “an” entity refers to one or more of that entity; for example, “a nucleotide sequence,” is understood to represent one or more nucleotide sequences. As such, the terms “a” (or “an”), “one or more,” and “at least one” can be used interchangeably herein.

[0099] Furthermore, “and / or” where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. Thus, the term “and / or” as used in a phrase such as “A and / or B” herein is intended to include “A and B,” “A or B,” “A”(alone), and “B” (alone). Likewise, the term “and / or” as used in a phrase such as “A, B, and / or C” is intended to encompass each of the following aspects: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone).

[0100] It is understood that wherever aspects are described herein with the language “comprising,” otherwise analogous aspects described in terms of “consisting of’ and / or “consisting essentially of’ are also provided. As used herein, the terms “comprise” and “include” and variations thereof (e.g., “comprises,” “comprising,” “includes,” and “including”) will be understood to indicate the inclusion of a stated component, feature, element, or step or group of components, features, elements or steps but not the exclusion of any other component, feature, element, or step or group of components, features, elements, or steps. Any of the terms “comprising,” “consisting essentially of,” and “consisting of’ may be replaced with either of the other two terms, while retaining their ordinary meanings.

[0101] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is related. For example, the Concise Dictionary of Biomedicine and Molecular Biology, Juo, Pei- Show, 2nded., 2002, CRC Press; The Dictionary of Cell and Molecular Biology, 3rded., 1999, Academic Press; and the Oxford Dictionary Of Biochemistry And Molecular Biology, Revised, 2000, Oxford University Press, provide one of skill with a general dictionary of many of the terms used in this disclosure.

[0102] Units, prefixes, and symbols are denoted in their Systeme International de Unites (SI) accepted form. Numeric ranges are inclusive of the numbers defining the range. Unless otherwise indicated, nucleotide sequences are written left to right in 5’ to 3’ orientation. Amino acid sequences are written left to right in amino to carboxy orientation. The headings provided herein are not limitations of the various aspects of the disclosure, which can be had by reference to the specification as a whole. Accordingly, the terms defined immediately below are more fully defined by reference to the specification in its entirety.

[0103] The term “about” is used herein to mean approximately, roughly, around, or in the regions of. When the term “about” is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the numerical values set forth. In general, the term “about” can modify a numerical value above and below the stated value by a variance of, e.g., 10 percent, up or down (higher or lower).

[0104] The term “T cell engaging molecule,” as used herein, refers to any molecule that can target an antigen on a target cell, e.g., a STEAP2 on a cancer cell, and also bind a protein expressed on a T cell, e.g., a CD3 and / or CD8 protein. A T cell engaging molecule can comprise at least one antigen binding portion, or antigen binding arm, and at least one T cell binding portion, or T cell binding arm. The term “antigen binding portion” and “antigen binding arm” are used interchangeably. A T cell engaging molecule can include portions of monoclonal antibodies, chimeric antibodies, humanized antibodies and human antibodies. For example, T cell engaging molecules can comprise an antigen binding portion or arm of an antibody, e.g., an anti-STEAP2 antibody and / or an anti-CD3 antibody and / or an anti-CD8 antibody and include (i) a Fab fragment (fragment from papain cleavage) or a similar monovalent fragment consisting of the VL, VH, LC and CHI domains; (ii) a F(ab’)2 fragment (fragment from pepsin cleavage) or a similar bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region; (iii) a Fd fragment consisting of the VH and CHI domains; (iv) a Fv fragment consisting of the VL and VH domains of a single arm of an antibody, (v) a dAb fragment (Ward et al., (1989) Nature 341:544- 546), which consists of a VH domain; (vi) an isolated complementarity determining region (CDR); (vii) a combination of two or more isolated CDRs which can optionally be joined by a synthetic linker; or (viii) single chain Fv (scFv). Antibody fragments are obtained using conventional techniques known to those with skill in the art, and the fragments are screened for utility in the same manner as are intact antibodies. Antigen binding portions or arms can be produced by recombinant DNA techniques, or by enzymatic or chemical cleavage of intact immunoglobulins. Ribbon diagrams of a kappa and a CHI chain interacting surface of a binding arm of a T cell engager and of a lambda and a CHI chain interacting surface of a binding arm of a T cell engager are shown in Figures. 2 and 3, respectively.

[0105] The terms “antigen binding arm” and “antigen binding portion,” as used herein, refer to the part of a molecule that binds to all or part of the target epitope and generally comprises six complementarity- determining regions (CDRs); three in the VH region: HCDR1, HCDR2 and HCDR3, and three in the VL region: LCDR1, LCDR2, and LCDR3. The six CDRs together define the paratope of the antigen binding portion or arm, which is the part of the antigen binding portion or arm which binds to the target epitope. The antigen binding portion or arm can also comprises just the three heavy chain CDRs. The term “epitope” as used herein refers to the part of an antigen that an antigen binding arm binds to. A monoclonal monospecific IgG antibody molecule containstwo antigen binding arms, each of which are able to bind the same epitope (i.e. it is bivalent for a single epitope).

[0106] An example of a bispecific antibody format that incorporates some of these modifications to improve efficient production of these molecules is a “DuetMab” described in Mazor 2015 and WO 2013 / 096291. DuetMab antibody molecules uses knobs-into-holes technology for heterodimerization of two distinct heavy chains and increases the efficacy of cognate heavy and light chain pairing by replacing the native disulfide bond in one of the CH1- CL interfaces with an engineered disulfide bond.

[0107] The term “valent,” as used herein, refers to the presence of a specified number of antigen binding portions or arms in the T cell engaging molecule that bind an epitope. For example, the term “trivalent,” as used herein, refers to a T cell engaging molecule that has three portions or arms that bind an antigen. The term “tetravalent,” as used herein, refers to a T cell engaging molecule that has four portions or arms that bind an antigen. The antigen binding portions or arms of a trivalent and / or tetravalent T cell engaging molecule can bind to a same antigenic molecule, can bind a same epitope on an antigenic molecule, can bind different epitopes on a same antigenic molecule and / or can bind different epitopes on different antigenic molecules. In some aspects of a bivalent molecule described herein, a single antigen binding domain binds to CD3 and a second antigen binding domain binds to another target, and is referred to as a Bispecific T-cell Engager DuetMab (“TED”; see Figure 1A). In some aspects of a trivalent molecule described herein, a single antigen binding domain binds to CD3 in the trivalent antibody, and two additional antigen binding domains bind to other targets, and is referred to as a Bispecific T-cell Engager DuetMab (“TED2”; see Figure IB). In some aspects of a trivalent molecule described herein, a single antigen binding domain binds to CD3 in the trivalent antibody, a single antigen binding domain binds to CD8, and a third antigen binding domain binds to another target, which is referred to as a Trispecific T-cell engager DuetMab (“TED3”; see Figure 1C). In some aspects of a tetravalent molecule described herein, a single antigen binding domain binds to CD3 in the tetravalent molecule, a single antigen binding domain binds to CD8, and a third and fourth antigen binding domain each bind to another target, or the same target, and may be referred to as a Tetraspecific T-cell engager DuetMab (“TED4”; see Figure ID). In some aspects, the TED4 format comprises two antigen binding domains that are capable of binding to the same target.

[0108] A natural evolution of bispecific antibodies has been the introduction of trispecific antibodies, which The term “linker,” as used herein, refers to a peptide chain of at least two amino acids, e.g., a glycine and / or a serine that connects two polypeptide chains, e.g., a heavy chain of an antigen binding arm and a heavy chain of a T cell binding arm. The linker can comprise one or more glycine and / or serine amino acids. The terms “linked” and “attached” and “fused” as used herein, refer to the association of two or more molecules. The linkage can be covalent or non- covalent. The linkage also can be genetic (i.e., recombinantly fused). Such linkages can be achieved using a wide variety of art recognized techniques, such as chemical conjugation and recombinant protein production. For example, a linker comprises at least one “GGGGS.”

[0109] In some aspects, the linkage between a binding domain and an Fc domain includes a standard hinge region. In some aspects, the hinge region is an IgGl hinge comprising the sequence DKTHTCPPCPAPE (SEQ ID NO: 155) between the CHI domain of the antigen binding arm and the CH2 domain of the Fc region.

[0110] The phrase “capable of being disulfide linked,” as used herein, refers to two polypeptide chains that contain at least one cysteine each in a location such that a disulfide bridge can be formed between the two polypeptide chains when they are present in a T cell engaging molecule.

[0111] The term “antibody” refers, in some aspects, to a protein comprising at least two heavy (H) chains and two light (L) chains inter-connected by disulfide bonds. Each heavy chain is comprised of a heavy chain variable region (abbreviated herein as VH) and a heavy chain constant region (abbreviated herein as CH). In some antibodies, e.g., naturally-occurring IgG antibodies, the heavy chain constant region is comprised of a hinge and three domains, CHI, CH2 and CH3. In some antibodies, e.g., naturally- occurring IgG antibodies, each light chain is comprised of a light chain variable region (abbreviated herein as VL) and a light chain constant domain. The light chain constant domain is comprised of one domain (abbreviated herein as CL). The VH and VL regions can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDR), interspersed with regions that are more conserved, termed framework regions (FR). The VH region and VL region comprise framework regions (FRs) on either side of each CDR, which provide a scaffold for the CDRs. From N-terminus to C-terminus, VH regions comprise the following structure: N term-[HFRl]-[HCDRl]-[HFR2]-[HCDR2]-[HFR3]- [HCDR3]-[HFR4]-C term; and VL regions comprise the following structure: N term-[LFRl]-[LCDR1]-[LFR2]-[LCDR2]-[LFR3]-[LCDR3]-[LFR4]-C term. An antibody can be from any of the commonly known isotypes, including but not limited to IgA, secretory IgA, IgG and IgM. The IgG isotype is divided in subclasses in certain species: IgGl, IgG2, IgG3 and IgG4 in humans, and IgGl, IgG2a, IgG2b and IgG3 in mice. Antibodies, e.g., IgGl, exist in several allotypes, which differ from each other in at most a few amino acids. Antibodies include, by way of example, both naturally-occurring and non-naturally-occurring antibodies; monoclonal and polyclonal antibodies; chimeric and humanized antibodies; human and nonhuman antibodies and wholly synthetic antibodies.

[0112] The variable regions of the heavy and light chains contain a binding domain (also called a paratope) that interacts with an antigen molecule (or an epitope on the antigen molecule, e.g., an epitope on a CD3 molecule). The constant regions of the antibodies can mediate the binding of the immunoglobulin to host tissues or factors, including various cells of the immune system (e.g., effector cells) and the first component (Clq) of the classical complement system. A heavy chain may have the C-terminal lysine or not. Unless specified otherwise herein, the amino acids in the variable regions are numbered using the Kabat numbering system and those in the constant regions are numbered using the EU numbering (Edelman, 2007). A light chain associates with a VH and CHI in the heavy chain to form an “antigen binding arm” and the variable domains in the antigen binding arm interact to form the paratope that binds the antigen. Light chains in natural antibodies are either “lambda (X)” or ’’kappa (K)” light chains, which differ in terms of their amino acid sequence. Light chains of the trivalent and / or tetraval ent T cell engager molecules described herein can also be chimeric light chains, e.g. contain a CL . and a VLK.

[0113] Antibodies and methods for their construction and use are well-known in the art and are described in, for example, Holliger & Hudson, Nature Biotechnology 23(9): 1126-1136 (2005). In view of today’s techniques in relation to monoclonal antibody technology, antibodies can be prepared to most targets. It is possible to take monoclonal and other antibody molecules and use techniques of recombinant DNA technology to produce other antibody, chimeric molecules, and / or T cell engaging molecules. Such techniques may involve introducing CDRs or variable regions of one antibody into a different antibody molecule or introducing attaching CDRs or variable regions to an antibody molecule.

[0114] As used herein, the term “affinity” refers to a measure of the strength of the binding of an antigen or target (such as an epitope) to its cognate binding domain (such as a paratope). Asused herein, the term “avidity” refers to the overall stability of the complex between a population of epitopes and paratopes (i.e., antigens and antigen binding arms).

[0115] The term “epitope” refers to a site on an antigen (e.g., STEAP2, CD3 or CD8) to which a trivalent and / or tetravalent T cell engaging molecule can bind. Epitopes can be formed both from contiguous amino acids (usually a linear epitope) or noncontiguous amino acids juxtaposed by tertiary folding of a protein (usually a conformational epitope). Epitopes formed from contiguous amino acids are typically, but not always, retained on exposure to denaturing solvents, whereas epitopes formed by tertiary folding are typically lost on treatment with denaturing solvents. An epitope typically includes at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 amino acids in a unique spatial conformation.

[0116] The term “binds to the same epitope” with reference to two or more antigen binding moieties means that the antigen binding moieties bind to the same segment of amino acid residues. Antigen binding moieties that “compete with another antibody for binding to a target” refer to antigen binding moieties that inhibit (partially or completely) the binding of the other antibody to the target.

[0117] As used herein, the terms “specific binding,” “selective binding,” “selectively binds,” and “specifically binds,” refer to an antigen binding portion or arm binding to an epitope on a predetermined antigen. Typically, the antigen binding portion or arm (i) binds with an equilibrium dissociation constant (KD) of approximately less than 1 O'7M, such as approximately less than 10'8M, 10'9M or IO'10M or even lower when determined by, e.g., surface plasmon resonance (SPR) technology in a BIACORE® 2000 instrument using a predetermined antigen, e.g., human STEAP2 or CD3 or CD8, as the analyte and the T cell engaging molecule as the ligand, or Scatchard analysis of binding of the T cell engaging molecule to antigen positive cells, and (ii) binds to the predetermined antigen with an affinity that is at least two-fold greater than its affinity for binding to a non-specific antigen (e.g., BSA, casein) other than the predetermined antigen or a closely-related antigen. Accordingly, a T cell engaging molecule that “specifically binds to human STEAP2” refers to an antigen binding portion or arm that binds to human STEAP2 with a KD of 10'7M or less, such as approximately less than 10'8M, 10'9M or IO'10M or even lower.

[0118] The term “polypeptide,” as used herein, is intended to encompass a singular “polypeptide” as well as plural “polypeptides,” and comprises any chain or chains of two or more amino acids. Thus, as used herein, a “peptide,” a “peptide subunit,” a “protein,” an “amino acidchain,” an “amino acid sequence,” or any other term used to refer to a chain or chains of two or more amino acids, are included in the definition of a “polypeptide,” even though each of these terms can have a more specific meaning. The term “polypeptide” can be used instead of, or interchangeably with, any of these terms. The term further includes polypeptides which have undergone post-translational or post-synthesis modifications, for example, conjugation of a palmitoyl group, glycosylation, acetylation, phosphorylation, amidation, derivatization by known protecting / blocking groups, disulfide bond formation, proteolytic cleavage, or modification by non-naturally occurring amino acids. The term “peptide,” as used herein, encompasses full length peptides and fragments, variants or derivatives thereof. A “peptide” as used herein can be part of a fusion polypeptide comprising additional components such as, e.g., an albumin or PEG moiety, to increase half-life. A peptide as used herein can also be derivatized in a number of different ways. A peptide can comprise modifications including e.g., conjugation of a palmitoyl group.

[0119] The term “conservative amino acid substitution,” as used herein, refers to a substitution of an amino acid residue with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine, tryptophan), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). Further, a predicted nonessential amino acid residue in an antigen binding arm can be replaced with another amino acid residue from the same side chain family.

[0120] The percent identity between two sequences is a function of the number of identical positions shared by the sequences (i.e., % homology = # of identical positions / total # of positions x 100), taking into account the number of gaps, and the length of each gap, which need to be introduced for optimal alignment of the two sequences. The comparison of sequences and determination of percent identity between two sequences can be accomplished using a mathematical algorithm, as described in the non-limiting examples below.

[0121] The percent identity between two nucleotide sequences can be determined using the GAP program in the GCG software package (available at worldwideweb.gcg.com), using a NWSgapdna.CMP matrix and a gap weight of 40, 50, 60, 70, or 80 and a length weight of 1, 2, 3,4, 5, or 6. The percent identity between two nucleotide or amino acid sequences can also be determined using the algorithm ofE. Meyers and W. Miller (CABIOS, 4: 11-17 (1989)) which has been incorporated into the ALIGN program (version 2.0), using a PAM120 weight residue table, a gap length penalty of 12 and a gap penalty of 4. In addition, the percent identity between two amino acid sequences can be determined using the Needleman and Wunsch (J. Mol. Biol. (48):444- 453 (1970)) algorithm which has been incorporated into the GAP program in the GCG software package (available at http: / / www.gcg.com), using either a Blossum 62 matrix or a PAM250 matrix, and a gap weight of 16, 14, 12, 10, 8, 6, or 4 and a length weight of 1, 2, 3, 4, 5, or 6.

[0122] The nucleic acid and protein sequences described herein can further be used as a “query sequence” to perform a search against public databases to, for example, identify related sequences. Such searches can be performed using the NBLAST and XBLAST programs (version 2.0) of Altschul, et al. (1990) J. Mol. Biol. 215:403-10. BLAST nucleotide searches can be performed with the NBLAST program, score = 100, word length = 12 to obtain nucleotide sequences homologous to the nucleic acid molecules described herein. BLAST protein searches can be performed with the XBLAST program, score = 50, word length = 3 to obtain amino acid sequences homologous to the protein molecules described herein. To obtain gapped alignments for comparison purposes, Gapped BLAST can be utilized as described in Altschul et al., (1997) Nucleic Acids Res. 25(17):3389-3402. When utilizing BLAST and Gapped BLAST programs, the default parameters of the respective programs (e.g., XBLAST and NBLAST) can be used.

[0123] The term “nucleic acid molecule,” as used herein, is intended to include DNA molecules and RNA molecules. A nucleic acid molecule can be single-stranded or doublestranded, and can be cDNA.

[0124] The terms “polynucleotide,” and “nucleic acid molecule,” as used herein, are intended to include DNA molecules and RNA molecules. A polynucleotide or nucleic acid molecule can be single-stranded or double-stranded, and can be cDNA.

[0125] The term “promoter,” as used herein, refers to a DNA sequence recognized by the machinery of a cell, or introduced synthetic machinery, required to initiate the specific transcription of a gene. The term “promoter” is also meant to encompass those nucleic acid elements sufficient for promoter-dependent gene expression controllable for cell-type specific, tissue-specific or inducible expression by external signals or agents; such elements can be locatedin the 5' or 3' regions of the native gene. In some aspects, the promoter can be a constitutively active promoter, a cell-type specific promoter, or an inducible promoter.

[0126] The term “IRES,” as used herein, refers to an element that promotes direct internal ribosome entry to the initiation codon, such as ATG, of a cistron (a protein encoding region), thereby leading to the cap- independent translation of the gene. See, e.g., Jackson R J et al., Trends Biochem Sci 15(12):477-83 (199); Jackson R J and Kaminski, A. RNA l(10):985-1000 (1995). Under translational control of an IRES translation proceeds in a cap-independent manner.

[0127] The term “termination signal sequence,” as used herein, can be any genetic element that causes RNA polymerase to terminate transcription, such as for example a polyadenylation signal sequence. A polyadenylation signal sequence is a recognition region necessary for endonuclease cleavage of an RNA transcript that is followed by the polyadenylation consensus sequence AATAAA. A polyadenylation signal sequence provides a “polyA site,” i.e., a site on a RNA transcript to which adenine residues will be added by post-transcriptional polyadenylation.

[0128] The terms “operatively linked,” “operatively inserted,” “operatively positioned,” “under control” or “under transcriptional control,” as used herein, mean that the promoter is in the correct location and orientation in relation to the nucleic acid to control RNA polymerase initiation and expression of the gene. The term “operably linked” means that a DNA sequence and a regulatory sequence(s) are connected in such a way as to permit gene expression when the appropriate molecules (e.g., transcriptional activator proteins) are bound to the regulatory sequence(s). The term “operably inserted” means that the DNA of interest introduced into a cell is positioned adjacent a DNA sequence which directs transcription and translation of the introduced DNA (i.e., facilitates the production of, e.g., a polypeptide encoded by a DNA of interest).

[0129] The term “vector,” as used herein, is intended to refer to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a “plasmid,” which refers to a circular double stranded DNA loop into which additional DNA segments can be ligated. Another type of vector is a viral vector, wherein additional DNA segments can be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) can be integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. Moreover, certain vectors are capable ofdirecting the expression of genes to which they are operatively linked. Such vectors are referred to herein as “recombinant expression vectors” (or simply, “expression vectors”). In general, expression vectors of utility in recombinant DNA techniques are often in the form of plasmids. The terms “plasmid” and “vector” can be used interchangeably as the plasmid is the most commonly used form of vector. However, also included are other forms of expression vectors, such as viral vectors (e.g., replication defective retroviruses, adenoviruses and adeno-associated viruses), which serve equivalent functions.

[0130] The term “recombinant host cell” (or simply “host cell”), as used herein, is intended to refer to a cell that comprises a nucleic acid that is not naturally present in the cell, and can be a cell into which a recombinant expression vector has been introduced. It should be understood that such terms are intended to refer not only to the particular subject cell but to the progeny of such a cell. Because certain modifications can occur in succeeding generations due to either mutation or environmental influences, such progeny cannot, in fact, be identical to the parent cell, but are still included within the scope of the term “host cell” as used herein.

[0131] The terms “subject,” “individual,” or “patient,” as used herein, refer to any organism to which a composition disclosed herein, e.g., a T cell engaging molecule can be administered, e.g., for experimental, diagnostic, prophylactic, and / or therapeutic purposes. Typical subjects include any animal (e.g., mammals such as mice, rats, rabbits, non-human primates, and humans). Mammalian subjects include, for example, humans, non-human primates, dogs, cats, guinea pigs, rabbits, rats, mice, horses, cattle, bears, and so on. A subject can seek or be in need of treatment, require treatment, be receiving treatment, be receiving treatment in the future, or be a human or animal who is under care by a trained professional for a particular disease or condition.

[0132] The terms “treat,” “treatment,” or “treatment of,” as used herein, refer to reducing disease pathology, reducing or eliminating disease symptoms, promoting increased survival rates, and / or reducing discomfort. For example, treating can refer to the ability of a therapy when administered to a subject, to reduce disease symptoms, signs, or causes. Treating also refers to mitigating or decreasing at least one clinical symptom and / or inhibition or delay in the progression of the condition and / or prevention or delay of the onset of a disease or illness.

[0133] The term “immune response” is as understood in the art generally refers to a biological response within a vertebrate against foreign agents or abnormal, e.g., cancerous cells, which response protects the organism against these agents and diseases caused by them. Animmune response is mediated by the action of one or more cells of the immune system (for example, a T lymphocyte, B lymphocyte, natural killer (NK) cell, macrophage, eosinophil, mast cell, dendritic cell or neutrophil) and soluble macromolecules produced by any of these cells or the liver (including antibodies, cytokines, and complement) that results in selective targeting, binding to, damage to, destruction of, and / or elimination from the vertebrate’s body of invading pathogens, cells or tissues infected with pathogens, cancerous or other abnormal cells, or, in cases of autoimmunity or pathological inflammation, normal human cells or tissues. An immune reaction includes, e.g., activation or inhibition of a T cell, e.g., an effector T cell, a Th cell, a CD4+cell, a CD8+T cell, or a Treg cell, or activation or inhibition of any other cell of the immune system, e.g., NK cell.

[0134] The term “immunotherapy,” as used herein refers to the treatment of a subject afflicted with, or at risk of contracting or suffering a recurrence of, a disease by a method comprising inducing, enhancing, suppressing or otherwise modifying the immune system or an immune response.

[0135] The term “cancer,” as used herein, refers to a broad group of diseases characterized by the uncontrolled growth of abnormal cells in the body. Unregulated cell division can result in the formation of malignant tumors or cells that invade neighboring tissues and can metastasize to distant parts of the body through the lymphatic system or bloodstream.

[0136] The terms “effective amount,” “therapeutically effective amount,” and a “sufficient amount” of, e.g., a T cell engaging molecule or a composition described herein refer to a quantity sufficient to, when administered to a subject including a human effect beneficial or desired results, including alleviation of symptoms; diminishment of the extent of a condition, disorder, or disease; attainment of a stabilized (i.e., not worsening) state of a condition, disorder, or disease; delay in onset or slowing of a condition, disorder, or disease progression; amelioration of a condition, disorder, or disease state or remission (whether partial or total), whether detectable or undetectable; amelioration of at least one measurable physical parameter, not necessarily discernible by a patient; or enhancement or improvement of a condition, disorder, or disease. In some aspects, treatment includes eliciting a clinically significant response without excessive levels of side effects. As such, a “therapeutically effective amount” or synonyms thereof depend on the context in which they are applied. In some aspects, a therapeutically effective amount of an agent (e.g., a T cell engaging molecule or a composition described herein) is an amount that results in abeneficial or desired result in a subject as compared to a control that does not receive the agent. The amount of a given agent (e.g., a T cell engaging molecule or a composition) will vary depending upon various factors, such as the given agent, the pharmaceutical formulation, the route of administration, the type of disease or disorder, the identity of the subject (e.g., age, sex, and / or weight) or host being treated, and the like.

[0137] The term “prophylactically effective amount,” as used herein, refers to an amount of an agent (e.g., a T cell engaging molecule or a composition) that delays, forestalls the onset, or blocks the onset or development or progression of a condition or disease for a period of time, including weeks, months, or years. The prophylactically effective amount can vary depending on the characteristics of an agent; how the agent is administered; the degree of risk of disease; and the history, age, weight, family history, genetic makeup of a subject; the types of preceding or concomitant treatments, if any; and other individual characteristics of the patient to be treated.

[0138] As used herein, the terms “ug” and “uM” are used interchangeably with “pg” and “pM,” respectively.

[0139] Various aspects described herein are described in further detail in the following subsections.II. Antigen Binding Arm

[0140] An antigen binding arm of the T cell engaging molecules described herein binds STEAP2. In some aspects, a T cell engaging molecule comprises one STEAP2 binding arm. In some aspects, a T cell engaging molecule binds two STEAP2 antigens.

[0141] In some aspects, an antigen binding arm of a T cell engaging molecule described herein can be of any format including an Fab, Fab’, F(ab’)2, Fd, Fv, single-chain fragment variable (scFv), single chain antibody, VHH, vNAR, nanobody (single-domain antibody), or any combination thereof. In some aspects, the antigen binding arm comprises a Fab.

[0142] In some aspects, an antigen binding arm comprises a variable heavy chain region (VH) and a variable light chain region (VL), wherein the VH comprises a VH complementarity determining region (CDR) 1, a VH-CDR2, a VH-CDR3; and wherein the VL comprises a VL- CDR1, a VL-CDR2, and VL-CDR3.

[0143] In some aspects, an antigen binding arm comprises a VH-CDR1 comprising an amino acid sequence selected from SEQ ID Nos: 1, 9, 17, 103, 111, 127, 135, and 143. In someaspects, an antigen binding arm comprises a VH-CDR2 comprising an amino acid sequence selected from SEQ ID Nos: 2, 10, 18, 104, 112, 128, 136, and 144. In some aspects, an antigen binding arm comprises a VH-CDR3 comprising an amino acid sequence selected from SEQ ID Nos: 3, 11, 19, 94, 96, 98, 105, 113, 129, 137, and 145.

[0144] In some aspects, an antigen binding arm comprises a VL-CDR1 comprising an amino acid sequence selected from SEQ ID Nos: 4, 12, 20, 100, 108, 130, 138, and 146. In some aspects, an antigen binding arm comprises a VL-CDR2 comprising an amino acid sequence selected from SEQ ID Nos: 5, 13, 21, 101, 109, 131, 139, and 147. In some aspects, an antigen binding arm comprises a VL-CDR3 comprising an amino acid sequence selected from SEQ ID Nos: 6, 14, 22, 102, 110, 132, 140, and 148.

[0145] In some aspects, an antigen binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 1, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 2, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 3, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 4, a VL-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 5, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 6.

[0146] In some aspects, an antigen binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 9, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 10, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 11, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 12, a VL- CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 13, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 14.

[0147] In some aspects, an antigen binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 17, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 18, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 19, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 20, a VL- CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 21, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 22.

[0148] In some aspects, an antigen binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 1, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 2, a VH-CDR3 comprising the amino acid sequence set forth in SEQ IDNO: 94, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 4, a VL-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 5, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 6.

[0149] In some aspects, an antigen binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 1, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 2, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 96, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 4, a VL-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 5, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 6.

[0150] In some aspects, an antigen binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 1, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 2, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 98, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 4, a VL-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 5, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 6.

[0151] In some aspects, an antigen binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 103, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 104, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 105, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 100, a VL-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 101, and a VL- CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 102.

[0152] In some aspects, an antigen binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 111, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 112, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 113, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 108, a VL-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 109, and a VL- CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 110.

[0153] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO:7. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 7.

[0154] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 15. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 15.

[0155] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 23. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 23.

[0156] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 95. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 95.

[0157] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 97. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 97.

[0158] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO:99. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 99.

[0159] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 106. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 106.

[0160] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 114. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 114.

[0161] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 133. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 133.

[0162] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 141. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 141.

[0163] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO:149. In some aspects, an antigen binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 149.

[0164] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 8. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 8.

[0165] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 16. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 16.

[0166] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 24. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 24.

[0167] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 107. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 107.

[0168] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO:115. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 115.

[0169] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 134. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 134.

[0170] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 142. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 142.

[0171] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 150. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 150.

[0172] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 7, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 8. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 7, and a VL comprising the amino acid sequence set forth in SEQ ID NO: 8.

[0173] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 15, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 16. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 15, and a VL comprising the amino acid sequence set forth in SEQ ID NO: 16.

[0174] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 23, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 24. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 23, and a VL comprising the amino acid sequence set forth in SEQ ID NO: 24.

[0175] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 95, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 8. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 95, and a VL comprising the amino acid sequence set forth in SEQ ID NO: 8.

[0176] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 97, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 16. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 97, and a VL comprising the amino acid sequence set forth in SEQ ID NO: 16.

[0177] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 99, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 24. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 99, and a VL comprising the amino acid sequence set forth in SEQ ID NO: 24.

[0178] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 106, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 107. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 106, and a VL comprising the amino acid sequence set forth in SEQ ID NO: 107.

[0179] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 114, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 115. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 114, and a VL comprising the amino acid sequence set forth in SEQ ID NO: 115.

[0180] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 133, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 134. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 133, and a VL comprising the amino acid sequence set forth in SEQ ID NO: 134.

[0181] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 141, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 142. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 141 , and a VL comprising the amino acid sequence set forth in SEQ ID NO: 142.

[0182] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 149, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 150. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising the amino acid sequence set forth in SEQ ID NO: 149, and a VL comprising the amino acid sequence set forth in SEQ ID NO: 150.

[0183] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149, and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 8, 16, 24, 107, 115, 134, 142, and 150. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence selected from SEQ ID Nos: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149, and a VL comprising the amino acid sequence selected from SEQ ID NO: 8, 16, 24, 107, 115, 134, 142, and 150.

[0184] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, an antigen binding arm comprises a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60 and 61.

[0185] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a light chain constant domain comprising an amino acid sequence having at least about80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, an antigen binding arm comprises a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0186] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 8 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 8 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61.

[0187] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 8 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 8 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0188] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 16 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 16 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60 , and 61.

[0189] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 16 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 16 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0190] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 24 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 24 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61.

[0191] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 24 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequenceselected from SEQ ID Nos: 62, 63, and 64. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 24 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0192] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 107 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 107 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60 , and 61.

[0193] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 107 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 107, and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0194] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 115 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, an antigen binding arm comprises aVL comprising an amino acid sequence set forth in SEQ ID NO: 115 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60 , and 61.

[0195] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 115 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 115, and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0196] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 115 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 115 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60 , and 61.

[0197] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 115 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, an antigen binding arm comprises aVL comprising an amino acid sequence set forth in SEQ ID NO: 115, and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0198] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 115 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 115 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60 , and 61.

[0199] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 134 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 134, and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0200] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 142 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, an antigen binding arm comprises aVL comprising an amino acid sequence set forth in SEQ ID NO: 142 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60 , and 61.

[0201] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 150 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, an antigen binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 150, and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0202] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 8 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence set forth in SEQ ID NO: 8 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64.

[0203] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 16 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64. In some aspects, a T cell engaging moleculecomprises an antigen binding arm comprising a VL comprising an amino acid sequence set forth in SEQ ID NO: 16 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64.

[0204] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 24 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence set forth in SEQ ID NO: 24 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64.

[0205] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 107 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence set forth in SEQ ID NO: 107 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64.

[0206] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 115 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence set forth in SEQ ID NO: 115 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64.

[0207] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 134 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence set forth in SEQ ID NO: 134 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64.

[0208] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 142 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence set forth in SEQ ID NO: 142 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64.

[0209] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO:150 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VL comprising an amino acid sequence set forth in SEQ ID NO: 150 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64.

[0210] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, an antigen binding arm comprises a heavy chain constant region comprising an amino acid sequence selected from SEQ ID Nos: 65-80.

[0211] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 7 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 7 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65- 80.

[0212] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 15 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequenceselected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 15 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65-80.

[0213] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 23 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 23 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65-80.

[0214] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 95 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 95 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65-80.

[0215] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 97 and a heavy chain constant region comprising an amino acid sequence having at least about80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 97 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65-80.

[0216] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 99 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 99 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65-80.

[0217] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 106 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 106 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65-80.

[0218] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 114 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 114 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65-80.

[0219] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 133 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 133 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65-80.

[0220] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 141 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 141 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65-80.

[0221] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 149 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence set forth in SEQ ID NO: 149 and a heavy chain constant region comprising an amino acid sequence selected from SEQ ID NO: 65-80.

[0222] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 7 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0223] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 15 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0224] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO:23 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0225] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 95 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0226] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 97 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0227] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 99 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0228] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 106 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0229] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 114 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0230] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 133 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0231] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 141 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0232] In some aspects, a T cell engaging molecule comprises an antigen binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 149 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 88, and 91.

[0233] In some aspects, a T cell engaging molecule comprises a heavy chain that comprises a STEAP2 antigen binding region fused to a CD8 binding region. In some aspects, the antigen binding arm further comprises a light chain comprising a STEAP2 binding region.

[0234] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a light chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 25. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 25.

[0235] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a light chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 116. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 116.

[0236] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a light chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 117. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 117.

[0237] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a light chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQID NO: 118. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 118.

[0238] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a light chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 119. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 119.

[0239] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 26. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 26.

[0240] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 120. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 120.

[0241] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 121. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 121.

[0242] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQID NO: 122. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 122.

[0243] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 123. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 123.

[0244] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 124. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 124.

[0245] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 125. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 125.

[0246] In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 126. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 126.In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 26 and a light chain comprising an amino acid sequence having at least about 80%, at least about 85%, atleast about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 25. In some aspects, a T cell engaging molecule comprises a STEAP2 binding arm that comprises a heavy chain comprising the amino acid sequence set forth in SEQ ID NO: 26 and a light chain comprising the amino acid sequence set forth in SEQ ID NO: 25.III. T Cell Binding Arm

[0247] A T cell engaging molecule described herein comprises at least one T cell binding arm. In some aspects, the T cell engaging molecule described herein comprises two T cell binding arms. In some aspects, the T cell engaging molecule comprises at least one T cell binding arm that binds a CD3 antigen. In some aspects, the T cell engaging molecule comprises at least one T cell binding arm that binds a CD8 antigen. In some aspects, the T cell engaging molecule comprises at least one T cell binding arm that binds a CD3 antigen and at least one T cell binding arm that binds a CD8 antigen. In some aspects, the T cell binding arm comprises a heavy variable domain and a light chain variable domain. In some aspects, the T cell binding arm comprises only a heavy chain variable domain.

[0248] In some aspects, a T cell binding arm of the T cell engaging molecules described herein can be of any format including an Fab, Fab’, F(ab’)2, Fd, Fv, single-chain fragment variable (scFv), single chain antibody, VHH, vNAR, nanobody (single-domain antibody), or any combination thereof. In some aspects, the antigen binding arm comprises a Fab. . In some aspects, the antigen binding arm comprises a VHH.

[0249] In some aspects, a T cell binding arm comprises a variable heavy chain region (VH) and a variable light chain region (VL), wherein the VH comprises a VH-CDR1 , a VH-CDR2, a VH-CDR3; and wherein the VL comprises a VL-CDR1, a VL-CDR2, and VL-CDR3.

[0250] In some aspects, a T cell binding arm of the T cell engaging molecule is capable of binding CD3. CD3 (cluster of differentiation 3) is a protein complex composed of four subunits, the CD3y chain, the CD35 chain, and two CD3s chains. CD3 associates with the T-cell receptor and the chain to generate an activation signal in T lymphocytes. T cell engaging molecules that target CD3 and a target cell antigen (or antigens), e.g., STEAP2 can force a temporary interaction between the target cell (or cells), e.g., a STEAP2 expressing cancer cell and a T cell, causing crosslinking, T-cell activation, and subsequent antigen-dependent T cell killing of the target cell. Insome aspects, the T cell engaging molecule binds monoval ently to the CD3 protein and the T-cell receptor is only cross-linked and activated upon binding of the target cell.

[0251] In some aspects, a T cell binding arm comprises a VH-CDR1 comprising an amino acid sequence selected from SEQ ID Nos: 36, 40, and 44. In some aspects, a T cell binding arm comprises a VH-CDR2 comprising an amino acid sequence selected from SEQ ID Nos: 37, 41, and 45. In some aspects, a T cell binding arm comprises a VH-CDR3 comprising an amino acid sequence selected from SEQ ID Nos: 38, 42, and 46.

[0252] In some aspects, a T cell binding arm comprises a VL-CDR1 comprising an amino acid sequence selected from SEQ ID Nos: 27 and 31. In some aspects, a T cell binding arm comprises a VL-CDR2 comprising an amino acid sequence selected from SEQ ID Nos: 28 and 32. In some aspects, a T cell binding arm comprises a VL-CDR3 comprising an amino acid sequence selected from SEQ ID Nos: 29 and 33.

[0253] In some aspects, a T cell binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 36, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 37, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 38, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 31, a VL- CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 32, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 33.

[0254] In some aspects, a T cell binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 36, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 37, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 38, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 27, a VL- CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 28, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 29.

[0255] In some aspects, a T cell binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 40, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 41, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 42, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 31, a VL- CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 32, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 33.

[0256] In some aspects, a T cell binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 40, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 41, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 42, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 27, a VL- CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 28, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 29.

[0257] In some aspects, a T cell binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 44, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 45, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 46, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 31, a VL- CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 32, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 33.

[0258] In some aspects, a T cell binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 44, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 45, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 46, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 27, a VL- CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 28, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 29.

[0259] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 39. In some aspects, a T cell binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 39.

[0260] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 43. In some aspects, a T cell binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 43.

[0261] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 47. In some aspects, a T cell binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 47.

[0262] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 34. In some aspects, a T cell binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 34.

[0263] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30. In some aspects, a T cell binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 30.

[0264] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 39 and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 34.

[0265] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 39 and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, atleast about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30.

[0266] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 43 and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 34.

[0267] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 43 and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30.

[0268] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 47 and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 34.

[0269] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 47 and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30.

[0270] In some aspects, a T cell binding arm comprises the VH-CDR1, VH-CDR2, and VH-CDR3 present in the VH region having the amino acid sequence set forth in SEQ ID NO: 39; and the VL-CDR1, VL-CDR2, and VL-CDR3 present in the VL region having the amino acid sequence set forth in SEQ ID NO: 34.

[0271] In some aspects, a T cell binding arm comprises the VH-CDR1, VH-CDR2, and VH-CDR3 present in the VH region having the amino acid sequence set forth in SEQ ID NO: 39; and the VL-CDR1, VL-CDR2, and VL-CDR3 present in the VL region having the amino acid sequence set forth in SEQ ID NO: 30.

[0272] In some aspects, a T cell binding arm comprises the VH-CDR1, VH-CDR2, and VH-CDR3 present in the VH region having the amino acid sequence set forth in SEQ ID NO: 43; and the VL-CDR1, VL-CDR2, and VL-CDR3 present in the VL region having the amino acid sequence set forth in SEQ ID NO: 34.

[0273] In some aspects, a T cell binding arm comprises the VH-CDR1, VH-CDR2, and VH-CDR3 present in the VH region having the amino acid sequence set forth in SEQ ID NO: 43; and the VL-CDR1, VL-CDR2, and VL-CDR3 present in the VL region having the amino acid sequence set forth in SEQ ID NO: 30.

[0274] In some aspects, a T cell binding arm comprises the VH-CDR1, VH-CDR2, and VH-CDR3 present in the VH region having the amino acid sequence set forth in SEQ ID NO: 47; and the VL-CDR1, VL-CDR2, and VL-CDR3 present in the VL region having the amino acid sequence set forth in SEQ ID NO: 34.

[0275] In some aspects, a T cell binding arm comprises the VH-CDR1, VH-CDR2, and VH-CDR3 present in the VH region having the amino acid sequence set forth in SEQ ID NO: 47; and the VL-CDR1, VL-CDR2, and VL-CDR3 present in the VL region having the amino acid sequence set forth in SEQ ID NO: 30.

[0276] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, a T cell binding arm comprises a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60 and 61.

[0277] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, a T cell binding arm comprises a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0278] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 34 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61.

[0279] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 34 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0280] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61.

[0281] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0282] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 34 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64.

[0283] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 60, 61, 63, and 64.

[0284] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80. In some aspects, a T cell binding arm comprises a heavy chain constant region comprising an amino acid sequence selected from SEQ ID Nos: 65-80.

[0285] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 39 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80.

[0286] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 43 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80.

[0287] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 47 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 65-80.

[0288] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 39 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, and 80.

[0289] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 43 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, and 80.

[0290] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 47 and a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 72, 73, 74, 75, 76, 77, 78, 79, and 80.In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 81 or 82. In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a heavy chain comprising an amino acid sequence set forth in SEQ ID NO: 81 or 82.

[0291] In some aspects, one of the T cell binding arms is capable of binding CD8. CD8 (cluster of differentiation 8) is a dimer consisting of a pair of CD8 chains. The most common form of CD8 is composed of a CD8-a and CD8-0 chain. CD8 serves as the co-receptor on MCHI- restricted T-cells and acts to enhance the antigen sensitivity of CD8+ T-cells by binding to a largely invariant region of MHCI at a site distinct from where the T-cell receptor binds.

[0292] In some embodiments, a T cell engaging molecule comprises a T cell binding arm that is capable of binding CD3 and a T cell binding arm is capable of binding CD8.

[0293] In some aspects, a T cell binding arm comprises a VH-CDR1 comprising an amino acid sequence selected from SEQ ID Nos: 48 and 84. In some aspects, the T cell binding arm comprises a VH-CDR2 comprising an amino acid sequence selected from SEQ ID Nos: 49 and 85. In some aspects, the T cell binding arm comprises a VH-CDR3 comprising an amino acid sequence selected from SEQ ID Nos: 50 and 86.

[0294] In some aspects, a T cell binding arm comprises a VL-CDR1 comprising an amino acid sequence set forth in SEQ ID NO: 51. In some aspects, wherein the T cell binding arm comprises a VL-CDR2 comprising an amino acid sequence set forth in SEQ ID NO: 52. In some aspects, a T cell binding arm comprises a VL-CDR3 comprising an amino acid sequence set forth in SEQ ID NO: 53.

[0295] In some aspects, a T cell binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 48, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 49, a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 50, a VL-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 51, a VL- CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 52, and a VL-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 53.

[0296] In some aspects, a T cell binding arm comprises a VH-CDR1 comprising the amino acid sequence set forth in SEQ ID NO: 84, a VH-CDR2 comprising the amino acid sequence set forth in SEQ ID NO: 85, and a VH-CDR3 comprising the amino acid sequence set forth in SEQ ID NO: 86. In some aspects, a T cell binding arm comprises the VH-CDR1, VH-CDR2, and VH- CDR3 present in the VHH region having the amino acid sequence set forth in SEQ ID NO: 83.

[0297] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 56. In some aspects, a T cell binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 56.

[0298] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO:54. In some aspects, a T cell binding arm comprises a VL comprising an amino acid sequence set forth in SEQ ID NO: 54.

[0299] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 56 and a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 54.

[0300] In some aspects, a T cell binding arm comprises the VH-CDR1, VH-CDR2, and VH-CDR3 present in the VH region having the amino acid sequence set forth in SEQ ID NO: 56; and the VL-CDR1, VL-CDR2, and VL-CDR3 present in the VL region having the amino acid sequence set forth in SEQ ID NO: 54.

[0301] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, a T cell binding arm comprises a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0302] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, a T cell binding arm comprises a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60 and 61.

[0303] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO:54 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64. In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence set forth in SEQ ID NO: 54 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 62, 63, and 64.

[0304] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 54 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61. In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VL comprising an amino acid sequence set forth in SEQ ID NO: 54 and a light chain constant domain comprising an amino acid sequence selected from SEQ ID Nos: 59, 60, and 61.

[0305] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 57, 65, 66, and 67. In some aspects, a T cell binding arm comprises a heavy chain constant region comprising an amino acid sequence selected from SEQ ID Nos: 57, 65, 66, and 67.

[0306] In some aspects, a T cell engaging molecule comprises a T cell binding arm comprising a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 83. In some aspects, a T cell binding arm comprises a VH comprising an amino acid sequence set forth in SEQ ID NO: 83.IV. Charge Pairs

[0307] The terms “charge pair(s)” and “charge mutation(s)” are used interchangeably herein and refer to oppositely charged amino acids, e.g., a positively charged amino acid residue and a negatively charged amino acid residue, one of which is located in a light chain region (e.g. constant light chain domain) and the other in a heavy chain region (e.g. constant heavy chain region 1 (CHI)) of an antigen and / or T cell binding arm, located at positions intended to promote association of the light and heavy chains. By “lambda charge pair”, it is meant a charge pair where a positively or negatively charged amino acid residue is located in a lambda light chain (e.g. CLX). By “kappa charge pair”, it is meant a charge pair where positively or negatively charged amino acid residue in the light chain is located in a kappa light chain (e.g. CLK).

[0308] Without wishing to be bound by theory, it is believed that the oppositely charged amino acid residues in the charge pair increase the attraction of the heavy chain to the light chain in an immunoglobulin, and / or T cell binding arm, thereby promoting formation of the immunoglobulin and / or T cell binding arm with the correct heavy and light chain.

[0309] At least one of the amino acid residues of the charge pair can be engineered into the immunoglobulin, and / or T cell binding arm (i.e. at least one amino acid residue in the pair is not a wild-type amino acid residue). In some aspects, both amino acid residues in the charge pair are engineered into the immunoglobulin and / or T cell binding arm (i.e. both amino acid residues in the pair are not wild-type amino acid residues).

[0310] In some embodiments, the positively charged amino acid residue in the charge pair is located on the light chain and the negatively charged amino acid residue in the charge pair is located on the corresponding heavy chain. In other embodiments, the negatively charged amino acid residue is located on the light chain and the positively charged amino acid residue in the charge pair is located on the corresponding heavy chain.

[0311] The amino acid residues of the charge pair are typically naturally occurring. Naturally occurring positively charged amino acid residues according to the present disclosure include arginine, lysine and histidine. Naturally occurring negatively charged amino acid residues according to the present disclosure include glutamic acid, serine, threonine and aspartic acid. Although serine and threonine are often described in the art as ‘uncharged’ , they have an isoelectric point below 6 and therefore are partially negatively charged at neutral pH. For the purposes of thecharge pairs disclosed herein, serine and threonine are examples of negatively charged amino acid residues (together with glutamic acid and aspartic acid).

[0312] In some aspects, a charge pair comprises a positively charged amino acid residue selected from arginine, lysine or histidine located at one of the positions in the charge pair and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine located at the other position in the charge pair. For example, the charge pair may comprise any one of the following pairs of amino acid residues: arginine and aspartic acid; arginine and glutamic acid; arginine and serine; arginine and threonine; lysine and aspartic acid; lysine and glutamic acid; lysine and serine; lysine and threonine; histidine and aspartic acid; histidine and glutamic acid; histidine and serine; and histidine and threonine.

[0313] Lambda Charge Pairs

[0314] Lambda charge pairs, as exemplified herein, can be introduced at several positions to improve pairing of the correct light and heavy chains in the antigen and / or T cell binding arm.

[0315] In some aspects, a lambda charge pair comprises a positively or negatively charged amino acid residue at position 117, 119, 134, 136 or 178 of the constant light chain lambda region (CLX). In some aspects, a lambda charge pair comprises a positively or negatively charged amino acid residue at position 141, 185, 128, 145, 183, 185, 173, or 187 of the CHI domain. As noted elsewhere, the numbering is according to EU numbering.

[0316] In some aspects, lambda charge pairs are located at one or more of the following pairs of positions:(iv) position 117 in the CLX. and position 141 in the CHI ;(ii) position 117 in the CLX and position 185 in the CHI ;(iii) position 119 in the CLX and position 128 in the CHI ;(iv) position 134 in the CLX and position 128 in the CHI ;(v) position 134 in the CLX and position 145 in the CHI ;(vi) position 134 in the CLX and position 183 in the CHI ;(vii) position 136 in the CLX and position 185 in the CHI ;(viii) position 178 in the CLX and position 173 in the CHI ; and(ix) position 117 in the CLX and position 187 in the CHI .

[0317] In some aspects, the lambda charge pair is located at position 117 in the CLX and position 141 in the CHI. For example, the lambda charge pair can be selected from the following list: arginine at position 117 of the CLX and aspartic acid at position 141 of the CHI ; arginine at position 117 of the CLX and glutamic acid at position 141 of the CHI ; arginine at position 117 of the CLX and serine at position 141 of the CHI ; arginine at position 117 of the CLX and threonine at position 141 of the CHI; lysine at position 117 of the CLX and aspartic acid at position 141 of the CHI ; lysine at position 117 of the CLX and glutamic acid at position 141 of the CHI; lysine at position 117 of the CLX and serine at position 141 of the CHI ; and lysine at position 117 of the CLX and threonine at position 141 of the CHI.

[0318] In some aspects, a lambda charge pair is selected from any one of a. to f. of the above list. In some aspects, a lambda charge pair is selected from any one of a. to e. of the above list. In some aspects, a lambda charge pair is selected from any one of a., b., and e. of the above list. In some aspects, a lambda charge pair is a.

[0319] In some aspects, a lambda charge pair is located at position 117 in the CLX and position 185 in the CHI. For example, a lambda charge pair can be selected from the following list:

[0320] arginine at position 117 of the CLX and aspartic acid at position 185 of the CHI; arginine at position 117 of the CLX and glutamic acid at position 185 of the CHI ; arginine at position 117 of the CLX and serine at position 185 of the CHI ; arginine at position 117 of the CLX and threonine at position 185 of the CHI; lysine at position 117 of the CLX and aspartic acid at position 185 of the CHI; lysine at position 117 of the CLX and glutamic acid at position 185 of the CHI;lysine at position 117 of the CLX and serine at position 185 of the CHI; and lysine at position 117 of the CLX and threonine at position 185 of the CHI.

[0321] In some aspects, a lambda charge pair is located at position 119 in the CLX and position 128 in the CHI domain. For example, a lambda charge pair can be selected from the following list: arginine at position 119 of the CLX and aspartic acid at position 128 of the CHI ; arginine at position 119 of the CLX and glutamic acid at position 128 of the CHI ; arginine at position 119 of the CLX and serine at position 128 of the CHI ; arginine at position 119 of the CLX and threonine at position 128 of the CHI; lysine at position 119 of the CLX and aspartic acid at position 128 of the CHI ; lysine at position 119 of the CLX and glutamic acid at position 128 of the CHI; lysine at position 119 of the CLX and serine at position 128 of the CHI ; and lysine at position 119 of the CLX and threonine at position 128 of the CHI.

[0322] In some aspects, a lambda charge pair is located at position 134 in the CLX and position 128 in the CHI domain. For example, a lambda charge pair can be selected from the following list: arginine at position 134 of the CLX and aspartic acid at position 128 of the CHI ; arginine at position 134 of the CLX and glutamic acid at position 128 of the CHI; arginine at position 134 of the CLX and serine at position 128 of the CHI ; arginine at position 134 of the CLX and threonine at position 128 of the CHI; lysine at position 134 of the CLX and aspartic acid at position 128 of the CHI; lysine at position 134 of the CLX and glutamic acid at position 128 of the CHI; lysine at position 134 of the CLX and serine at position 128 of the CHI; and lysine at position 134 of the CLX and threonine at position 128 of the CHI.

[0323] In some aspects, a lambda charge pair is located at position 134 in the CLX and position 145 in the CHI domain. For example, a lambda charge pair can be selected from the following list: arginine at position 134 of the CLX and aspartic acid at position 145 of the CHI ; arginine at position 134 of the CLX and glutamic acid at position 145 of the CHI ; arginine at position 134 of the CLX and serine at position 145 of the CHI ; arginine at position 134 of the CLX and threonine at position 145 of the CHI;lysine at position 134 of the CLX and aspartic acid at position 145 of the CHI; lysine at position 134 of the CLX and glutamic acid at position 145 of the CHI; lysine at position 134 of the CLX and serine at position 145 of the CHI; and lysine at position 134 of the CLX and threonine at position 145 of the CHI.

[0324] In some aspects, a lambda charge pair is located at position 134 in the CLX and position 183 in the CHI domain. For example, a lambda charge pair can be selected from the following list: arginine at position 134 of the CLX and aspartic acid at position 183 of the CHI ; arginine at position 134 of the CLX and glutamic acid at position 183 of the CHI; arginine at position 134 of the CLX and serine at position 183 of the CHI; arginine at position 134 of the CLX and threonine at position 183 of the CHI; lysine at position 134 of the CLX and aspartic acid at position 183 of the CHI; lysine at position 134 of the CLX and glutamic acid at position 183 of the CHI; lysine at position 134 of the CLX and serine at position 183 of the CHI; and lysine at position 134 of the CLX and threonine at position 183 of the CHI.

[0325] In some aspects, a lambda charge pair is a lysine at position 134 of the CLX, and an aspartic acid or a serine at position 183 of the CHI domain.

[0326] In some aspects, a lambda charge pair is located at position 136 in the CLX and position 185 in the CHI domain. For example, a lambda charge pair can be selected from the following list: arginine at position 136 of the CLX and aspartic acid at position 185 of the CHI ; arginine at position 136 of the CLX and glutamic acid at position 185 of the CHI; arginine at position 136 of the CLX and serine at position 185 of the CHI; arginine at position 136 of the CLX and threonine at position 185 of the CHI; lysine at position 136 of the CLX and aspartic acid at position 185 of the CHI; lysine at position 136 of the CLX and glutamic acid at position 185 of the CHI; lysine at position 136 of the CLX and serine at position 185 of the CHI; and lysine at position 136 of the CLX and threonine at position 185 of the CHI.

[0327] In some aspects, a lambda charge pair is located at position 178 in the CLX and position 173 in the CHI domain. For example, a lambda charge pair can be selected from the following list:arginine at position 178 of the CLX and aspartic acid at position 173 of the CHI; arginine at position 178 of the CLX and glutamic acid at position 173 of the CHI ; arginine at position 178 of the CLX and serine at position 173 of the CHI ; arginine at position 178 of the CLX and threonine at position 173 of the CHI; lysine at position 178 of the CLX and aspartic acid at position 173 of the CHI; lysine at position 178 of the CLX and glutamic acid at position 173 of the CHI; lysine at position 178 of the CLX and serine at position 173 of the CHI; and lysine at position 178 of the CLX and threonine at position 173 of the CHI.

[0328] In some aspects, an antigen and / or T cell binding arm comprising a lambda charge pair comprises more than one lambda charge pair. For example, a first antigen and / or T cell binding arm may comprise two, three, four, five, six, seven, eight or nine lambda charge pairs at positions (i) to (ix) described above.

[0329] In some aspects, a first antigen and / or T cell binding arm comprises a kappa charge pair and a second antigen binding arm and / or second T cell binding arm both comprise lambda charge pairs, wherein the charged amino acid residues located on a second antigen binding CHI domain and CLX are the opposite charge to those located on a second T cell binding CHI domain and CLX.

[0330] In some exemplary aspects, a positively charged amino acid residue in the lambda charge pair is located on a light chain and the negatively charged amino acid residue in the lambda charge pair is located on a heavy chain. In some aspects, a negatively charged amino acid residue is located on a light chain and a positively charged amino acid residue in the lambda charge pair is located on a heavy chain.

[0331] Kappa Charge Pairs

[0332] In the T cell engaging molecules described herein, at least one antigen and / or T cell binding arm comprises a kappa charge pair. As described above, kappa charge pairs refer to a positively charged amino acid residue and a negatively charged amino acid residue, one of which is located in a kappa light chain (e.g. CLK) and the other in a heavy chain (e.g. CHI) of an antigen and / or T cell binding arm, located at positions intended to promote association of a light chain and CHI of a second antigen and / or T cell binding arm.

[0333] In some aspects, an antigen and / or T cell binding arm(s) containing a CLK comprises a kappa charge pair located at position 133 in the CLK and position 183 in the secondCHI . In some aspects, a negatively charged amino acid residue in a kappa charge pair is at position 133 of the CLK and a positively charged amino acid residue in a kappa charge pair 183 of the second CHI. In some aspects, a positively charged amino acid residue in a kappa charge pair is at position 133 of the CLK and a negatively charged amino acid residue in a kappa charge pair 183 of the second CHI. In some aspects, a negatively charged amino acid residue (e.g. at position 133 of the CLK) is a glutamic acid, and wherein a positively charged amino acid residue (e.g. at position 183 of the second CHI) is a lysine. As noted, this numbering is according to EU numbering.

[0334] In some aspects, a second antigen binding arm and a second T cell binding arm both comprise a kappa charge pair. In some aspects, a first antigen binding arm comprises a kappa charge pair and a second antigen binding arm and second T cell binding arm comprise a lambda charge pair.

[0335] In some aspects, a positively charged amino acid residue in a kappa charge pair in a second antigen binding arm is located on a second CHI and a negatively charged amino acid residue located on a second light chain; and a positively charged amino acid residue in a kappa charge pair in the second T cell binding arm is located on a third light chain and the negatively charged amino acid residue located on a third CHI . In some aspects, a positively charged amino acid residue in a kappa charge pair in a second antigen binding arm is located on a second light chain and a negatively charged amino acid residue located on a second CHI; and a positively charged amino acid residue in a kappa charge pair in a second antigen binding arm is located on a third CHI and a negatively charged amino acid residue located on the a light chain

[0336] In some aspects, a first antigen binding arm comprises a lambda charge pair comprising a positively charged amino acid residue and a negatively charged amino acid residue located at the interface between the first CHI and the CLX; a second antigen binding arm comprises a kappa charge pair comprising a positively charged amino acid residue and a negatively charged amino acid residue located at the interface between the second CHI and the CLK of the second light chain; and a second T cell binding arm comprises a kappa charge pair comprising a positively charged amino acid residue and a negatively charged amino acid residue located at the interface between the third CHI and the CLK of the third light chain, and wherein the charged amino acid residues located on the third CHI and CLK of the third light chain are the opposite charge to those located on the second CHI and the CLK of the second light chain.

[0337] In other aspects, a first antigen binding arm contains a kappa charge pair and a second antigen binding arm and second T cell binding arm contain oppositely charged lambda charge pairs. In some aspects, a first antigen binding arm comprises a kappa charge pair comprising a positively charged amino acid residue and a negatively charged amino acid residue located at the interface between the first CHI and the CLK; a second antigen binding arm comprises a lambda charge pair comprising a positively charged amino acid residue and a negatively charged amino acid residue located at the interface between the second CHI and the CLX of the second light chain; and a second T cell binding arm comprises a lambda charge pair comprising a positively charged amino acid residue and a negatively charged amino acid residue located at the interface between a third CHI and a CLX of a third light chain, and wherein the charged amino acid residues located on a third CHI and CLX of a third light chain are the opposite charge to those located on a second CHI and the CLX of the second light chain.

[0338] For example, a charge pair in a second antigen binding arm may be formed from a positively charged amino acid residue in a second CHI and a negatively charged amino acid residue in a second light chain, and a kappa charge pair in a second T cell binding arm may be formed from a negatively charged amino acid residue in a third CHI and a positively charged amino acid residue in a third light chain.

[0339] Alternatively, the charge pair in a second antigen binding arm may be formed from a negatively charged amino acid residue in a second CHI and a positively charged amino acid residue in a second light chain, and a kappa charge pair in a second T cell binding arm may be formed from a positively charged amino acid residue in a third CHI and a negatively charged amino acid residue in a third light chain.

[0340] As described in the examples, several methods are known that can be used to determine correct light chain paring. These include mass spectrometry-based approaches that can be used to establish association of the correct heavy / light chain. In some aspects, when T cell engaging molecules contain a mixture of kappa and lambda light chains, the ratio of kappa and lambda light chains in the assembled T cell engaging molecule can be determined using microfluidics-based electrophoresis as a readout of the correct light chain ratio.

[0341] Accordingly, in some aspects, the T cell engaging molecule containing the lambda charge pair exhibits improved correct light chain pairing when compared to an equivalent T cell engaging molecule that lacks the lambda charge pair. In some aspects, the trivalent antibodycontaining the lambda charge pair exhibits a correct light chain ratio greater than 90%, 95%, 96%, 97%, 98% or 99% (e.g. as determined using a microfluidics-based electrophoresis method), optionally after the T cell engaging molecule has been purified using light chain affinity purification.

[0342] As described herein, techniques such as light chain affinity chromatography that utilizes affinity resins specific for either CLK or CLX can be used to selectively purify T cell engaging molecules based on their light chain. Examples of such affinity resins include the LambdaFabSelect and KappaSelect resins available from GE Healthcare. Such methods can be used to selectively purify T cell engaging molecules containing both CLK and CLX and can therefore be used to improve production of T cell engaging molecules.V. Engineered Disulfides

[0343] In some aspects, the T cell engaging molecules contain engineered disulfides in addition to the charge pairs. By “engineered disulfides” it is meant that a native inter-chain disulfide bond at the CHI -CL interface (e.g. at 220 of the CHI and 212 of the LC) of at least one of a first antigen binding arm, a second antigen binding arm, a first T cell binding arm, or a second T cell binding arm has been replaced by an engineered (non-native) interchain disulfide, while the other binding arm or arms contain the native interchain disulfide bond at the CHI -CL interface. An engineered disulfide is typically formed by engineering cysteines into the CL of a light chain and the CHI domain of the corresponding heavy chain and replacing the cysteines that normally form the interchain disulfide. Disclosure related to the introduction of engineered disulfide into antibodies for the purpose of promoting heterodimerization can found e.g., in U.S. Pat. No. 9,527,927 and Mazor, 2015, which are herein incorporated by reference in their entirety.

[0344] The formation of disulfide bonds between cysteine residues occurs during the folding of many proteins that enter the secretory pathway. As the polypeptide chain collapses, cysteines brought into proximity can form covalent linkages during a process catalyzed by members of the protein disulfide isomerase family. The term “disulfide link” or “disulfide linked” as used herein, refers to the single covalent bond formed from the coupling of thiol groups, especially of cysteine residues. In some aspects, the covalent linkage between two cysteines is between the two sulfur atoms of each residue. However, depending on the environment, not all protein species may have a disulfide present at all times, for example, in the event of disulfidereduction. Thus, the term “disulfide link” or “disulfide linked” (whether native or engineered), in some aspects, also refers to the presence of two cysteine residues that are capable of forming a disulfide link, irrespective of whether or not they are actually linked at that individual point in time.

[0345] In some aspects, a disulfide link between a light chain and CHI in at least one of the antigen and / or T cell binding arms is capable of being formed between a pair of cysteines engineered into the light chain and CHI domain of that antigen and / or T cell binding arm. In aspects, a disulfide link between a light chain and CHI in two of the binding arms (e.g. a first and a second antigen binding arm, a first and second T cell binding arms, a first antigen binding arm and a first T cell binding arm, or a second antigen binding arm and a second T cell binding arm) is capable of being formed between a pair of cysteines engineered into the light chain and CHI of those two binding arms.

[0346] In some aspects, a disulfide link between a first light chain and a CHI is capable of being formed between a pair of cysteines engineered into the first light chain and the first CHI. In some aspects, a disulfide link between a third light chain and third CHI is capable of being formed between a pair of cysteines engineered into the third light chain and the third CHI . As described above, the light chains may comprise a CLX or a CLK. In some aspects, a pair of cysteines engineered into the CLX and CHI are located at position 122 of the CLX and position 126 of the CHI, and wherein the same CLX comprises a non-cysteine residue at position 212 and the same CHI comprises a non-cysteine residue at position 220. In some aspects, the non-cysteine residues are valines.

[0347] In some aspects, a pair of cysteines engineered into a constant light chain kappa region (CLK) and CHI are located at position 121 of the CLK and position 126 of the CHI, and wherein the same CLK comprises a non-cysteine residue at position 214 and the same CHI comprises a non-cysteine residue at position 220. In some embodiments, the non-cysteine residues are valines.

[0348] In some aspects, a disulfide link between a first light chain and first CHI is capable of being formed between a pair of cysteines engineered into the first light chain and first CHI, a disulfide link formed between a second light chain and second CHI is formed between a pair of native cysteines, and a disulfide link formed between a third light chain and third CHI is either: formed between a pair of native cysteines; or capable of being formed between a pair of cysteinesengineered into the third light chain polypeptide and the third heavy chain polypeptide, wherein the pair of cysteines inserted into the third light and heavy chain polypeptides are at different amino acid residue positions to the pair of cysteines inserted into the first light and heavy chain polypeptides.

[0349] In some aspects, a disulfide link between a first light chain and first CHI is capable of being formed between a pair of cysteines engineered into position 122 of the CLX and position 126 of the first CHI, wherein the CLX comprises a non-cysteine residue at position 212 and the first CHI comprises a non-cysteine residue at position 220; a disulfide link formed between a second light chain and second CHI is formed between a pair of native cysteines; and a disulfide link capable of being formed between a third light chain and third CHI is capable of being formed between a pair of cysteines engineered into position 121 of the CLK and position 126 of the first CHI, wherein the CLK comprises a non-cysteine residue at position 214 and the first CHI comprises a non-cysteine residue at position 220.

[0350] In some aspects, a T cell engaging molecule comprises a first antigen binding arm with a lambda charge pair as described above and an engineered disulfide, a second antigen binding arm with a kappa charge pair as described above and a native disulfide, and a first T cell binding arm with a kappa charge pair as described above and an engineered disulfide.

[0351] In some aspects, a T cell engaging molecule comprises other combinations of charge pairs and engineered disulfides. In some aspects, a first antigen binding arm comprises a lambda charge pair and native disulfides, and a first and second T cell binding arms comprise a kappa charge pair and engineered disulfides. In some aspects, a first T cell binding arm comprises a kappa charge pair and engineered disulfides, and a first and second antigen binding arms comprise the lambda charge pair and native disulfides. In some aspects, a second antigen binding arm comprises a kappa charge pair and native disulfides, and a first and second T cell binding arm comprise the lambda charge pairs and engineered disulfides.VI. Fc Region Modifications

[0352] In some aspects, a first and second antigen binding arm further comprise a first and second Fc region (i.e. further comprising the CH2 and CH3 regions of a heavy chain).

[0353] In some aspects, a T cell engaging molecule comprises one or more modifications in one or more of the CHI, CH2 and CH3 domains that promote formation of a multivalent T cellengaging molecule by facilitating pairing of the first and second Fc regions. In some aspects, a T cell engaging molecule comprises a Knobs into Holes (KiH) Fc modification based on single amino acid substitutions in the CH3 domains that promote heavy chain heterodimerization as described in Ridgway, 1996. The knob variant heavy chain CH3 has a small amino acid has been replaced with a larger one, thereby generating a protuberance (knob) on the surface of said CH3 domain, and the hole variant has a large amino acid has replaced with a smaller one thereby generating a cavity (hole) on the surface of said CH3 domain. Additional modifications may also be introduced to stabilize the association between the heavy chains.

[0354] In some aspects, CH3 modifications to enhance heterodimerization include, for example, “hole” mutations Y407V / T366S / L368A on one Fc region and “knob” mutation T366W on the other Fc region. In some aspects, a T cell engaging molecule further include a stabilizing cystine mutations Y349C (e.g. on the Fc region with the “hole” mutation) and stabilizing S354C mutation on the other Fc region (e.g. on the Fc region with the “knob” mutation”.

[0355] In some aspects, a substitution to generate a knob is a substitution to tryptophan at position 366 and a substitution to generate a hole is one or more of the following: iv) a substitution to valine at position 407; ii) a substitution to serine at position 366; and iii) a substitution to alanine at position 368.

[0356] In some aspects, a T cell engaging molecule comprises a “knob” present on a first antigen binding arm containing a lambda charge pair and a hole on a second antigen binding arm containing one of the kappa charge pairs. However, the opposite arrangement is also specifically contemplated, i.e. where the “hole” is present on a CH3 of a first antigen and / or T cell binding arm and the “knob” is present on a CH3 of a second antigen and / or T cell binding arm.

[0357] Other examples of CH3 modification to enhance heterodimerization are described in, e.g. Table 1 of Brinkmann and Kontermann, 2017 MABS 9(2), 182-212, which is herein specifically incorporated by reference.

[0358] For example, the one Fc region may include a modification to allow fractionated elution by protein A chromatography as described in Tustian, 2016. Briefly, one of the Fc regions may comprise a modification that ablates binding to protein A (termed Fc*), allowing for selective purification of a heterodimeric FcFc* multivalent product. Examples of suitable modifications for generating an Fc* region include substitution of H435 with arginine and Y436 with phenylalanine.

[0359] Other Fc modifications that can be used in addition to those used for enhancing heterodimerization are those that reduce or abrogate binding of a T cell engaging molecule to one or more Fey receptors, such as FcyRI, FcyRIIa, FcyRIIb, FcyRIII and / or to complement. Such mutations reduce or abrogate Fc effector functions. Mutations for reduce or abrogate binding of antibody molecule to one or more Fey receptors and complement are known and include the “triple mutation” or “TM” of L234F / L235E / P331S described for example in Organesyan, 2008.

[0360] In some aspects, a first antigen binding arm comprises a lambda charge pair and a first Fc region, a disulfide link between a first light chain and first CHI is capable of being formed between a pair of cysteines engineered into the first light chain and first CHI, and the first Fc region comprises a “knob” mutation; a second antigen binding arm comprises a kappa charge pair and a second Fc region, a disulfide link formed between the second light chain and second CHI is formed between a pair of native cysteines, and the second Fc region comprises a “hole” mutation; and a T cell binding arm comprises a kappa charge pair, wherein a charged amino acid residues located on a third CHI and CLK of a third light chain are the opposite charge to those located on the second CHI and the CLK of the second light chain, and wherein the disulfide link formed between the third light chain and third CHI is either: formed between a pair of native cysteines; or capable of being formed between a pair of cysteines engineered into the third light chain polypeptide and the third heavy chain polypeptide, wherein the pair of cysteines inserted into the third light and heavy chain polypeptides are at different amino acid residue positions to the pair of cysteines inserted into the first light and heavy chain polypeptides.

[0361] Non-limiting examples of multivalent T cell engaging molecules comprising a lambda charge pair, a kappa charge pair, engineered disulfides and modifications to facilitate heterodimerization of the first and second Fc regions are provided in the examples.

[0362] In some aspects, T cell engaging molecules comprise amino acid modifications. In some aspects, the modification is a substitution of an amino acid residue to any other naturally occurring or non-naturally occurring amino acid residue.

[0363] Naturally occurring residues may be divided into classes based on common side chain properties:

[0364] 1) nonpolar, aliphatic: glycine (G), methionine (M), alanine (A), valine (V), leucine(L), isoleucine (I);

[0365] 2) polar: cysteine I, asparagine (N), glutamine (Q), proline (P);

[0366] 3) polar, partially negatively charged: serine (S), threonine (T);

[0367] 4) acidic (negatively charged): aspartic acid (D), glutamic ad(E);

[0368] 5) basic (positively charged): histidine (H), lysine (K), arginine I;

[0369] 6) aromatic: tryptophan (W), tyrosine (Y), phenylalanine (F).

[0370] As described above, serine (S) and threonine (T) have an isoelectric point below 6 and are partially negatively charged at neutral pH, hence they are classed here as “polar, partially negatively charged.”

[0371] The amino acid substitution may be a conservative amino acid substitution. Conservative amino acid substitutions may involve exchange of a member of one of these classes with another member of the same class. For example, a conservative amino acid substitution may be a substitution of the acidic amino acid glutamic acid (E) for the acidic amino acid aspartic acid (D).

[0372] In one aspect, the antibody or antigen-binding fragment thereof does not have one or more effector functions. For instance, in one aspect, the antibody or antigen-binding fragment thereof has no antibody-dependent cellular cytotoxicity (ADCC) activity and / or no complementdependent cytotoxicity (CDC) activity. In one aspect, the antibody or antigen-binding fragment thereof does not bind to an Fc receptor and / or complement factors. In one aspect, the antibody or antigen-binding fragment thereof has no effector function. In one aspect, the antibody or antigenbinding fragment comprises an Fc region comprising a triple mutation (TM) which has reduced antibody dependent cellular cytotoxicity (ADCC) compared to an antibody having a wild type Fc region. In one aspect, the antibody or antigen binding fragment thereof has an Fc region which comprises a L234F / L235E / P331S triple mutation (TM). In one aspect, the antibody or antigenbinding fragment thereof has no effector function or. In one aspect, the antibody or antigen binding fragment thereof has an Fc region which comprises E233P / L234V / L235A / G236del / S267K. In one aspect, E233P / L234V / L235A / G236del / S267K is referred to as “null” or “Fc null”.VII. T Cell Engaging Molecules

[0373] The present disclosure provides T cell engaging molecules. T cell engaging molecules as described herein are capable of binding two different epitopes, either on the same or, in, di some aspects, different antigens. In some aspects, the T cell engaging molecules comprise at least one antigen binding arm and at least one T cell binding arm. According to the presentdisclosure, an “antigen binding arm” comprises a heavy chain comprising a VH domain and CHI domain and a light chain comprising a VL domain and a light chain constant domain, where the light chain constant domain is disulfide linked to the CHI domain, and wherein the antigen binding arm binds an antigen of interest. In some aspects, a “T cell binding arm” comprises a heavy chain comprising a VH domain and CHI domain and a light chain comprising a VL domain and a light chain constant domain, where the light chain constant domain is disulfide linked to the CHI domain, and wherein the T cell binding arm binds a T cell antigen.

[0374] In some aspects, an antigen binding arm and / or a T cell binding arm in the T cell engaging molecule further comprise an Fc region. In some aspects, an antigen binding arm and / or a T cell binding arm in the T cell engaging molecule comprise complete heavy chains (i.e. a VH domain, CHI domain, hinge region, CH2 domain and CH3 domain).

[0375] In some aspects, a T cell engaging molecule comprises (i) a first antigen binding arm comprising a heavy chain comprising a VH and a heavy chain constant region comprising a CHI, CH2, and CH3 domain, and a light chain comprising a VL and a light chain constant domain; (ii) a T cell binding arm comprising a heavy chain comprising a VH and a heavy chain constant region comprising a CHI, CH2, and CH3 domain, and a light chain comprising a VL and a light chain constant domain; and an Fc region, wherein the heavy chain of the antigen binding arm and the heavy chain of the T cell binding arm are attached to the Fc domain. An exemplary T cell engaging molecule is shown in Figure 1 A.

[0376] In some aspects, a T cell engaging molecule comprises (i) a first antigen binding arm comprising a heavy chain comprising a VH and a heavy chain constant region comprising a CHI, CH2, and CH3 domain, and a light chain comprising a VL and a light chain constant domain; (ii) a T cell binding arm comprising a heavy chain comprising a VH and a heavy chain constant region comprising a CHI, CH2, and CH3 domain, and a light chain comprising a VL and a light chain constant domain; and (iii) a second antigen binding arm comprising a heavy chain comprising a VH and a CHI domain and a light chain comprising a VL and a light chain constant domain; wherein the heavy chain of the second antigen binding arm is attached to the heavy chain of the T cell binding arm through a peptide linker. Exemplary T cell engaging molecules are shown in Figures 1A-1D.

[0377] In some aspects, a light chain of an antigen binding arm is disulfide linked to a heavy chain of the antigen binding arm in the T cell engaging molecule via a native inter-chaindisulfide bond (e.g., a disulfide bond present in an IgG antibody). In some aspects, a light chain of an antigen binding arm is disulfide linked to a heavy chain of the antigen binding arm in the T cell engaging molecule via an engineered disulfide bond. In some aspects, a light chain of a T cell binding arm is disulfide linked to a heavy chain of the T cell binding arm in the T cell engaging molecule via a native inter-chain disulfide bond. In some aspects, a light chain of a T cell binding arm is disulfide linked to a heavy chain of the T cell binding arm in the T cell engaging molecule via an engineered disulfide bond.

[0378] In some aspects, a heavy chain of an antigen binding arm is attached to a heavy chain of another antigen binding arm via a peptide linker. In some aspects, a heavy chain of an antigen binding arm is attached to a T cell binding arm via a peptide linker. In some aspects, a peptide linker consists of 5 to 100 amino acids, 5 to 50 amino acids, 5 to 25 amino acids, or 5 to 15 amino acids. In some aspects, a peptide linker is formed mainly from glycine and serine amino acid residues and in some aspects comprises the amino acid sequences GGGGS or SGGGGS. In some aspects, the peptide linker comprises or consists of SEQ ID NO: 89. In some aspects, the linker comprises from 1 to about 10 copies of SEQ ID NO: 89. In some aspects, the linker comprises 2 copies of SEQ ID NO: 89.

[0379] In some aspects, a T cell engaging molecule comprises (a) at least one antigen binding arm that binds STEAP2 and comprises a heavy chain comprising a heavy chain variable domain (VH) and a heavy chain constant domain (CHI); and a light chain comprising a light chain variable domain (VL) and a light chain constant domain (CL); (b) a T cell binding arm comprising a heavy chain comprising a VH domain and a CHI domain; a light chain comprising a VL domain and a light chain constant domain; and (c) an Fc domain comprising a first Fc region and a second Fc region, each Fc region comprising a CH2 domain and a CH3 domain, said Fc domain further comprising at least one modification to promote heterodimerization.

[0380] In some aspects, a T cell engaging molecule comprises an antigen binding arm that binds STEAP2 and comprises a heavy chain comprising a VH domain comprising a VH-CDR1 selected from SEQ ID Nos: 1, 9, 17, 103, 111, 127, 135, and 143; a VH-CDR2 selected from SEQ ID NO: 2, 10, 18, 104, and 112; a VH-CDR3 selected from SEQ ID NO: 3, 11, 19, 94, 96, 98, 105, 113, 129, 137, and 145; and a CHI domain. In some aspects, the antigen binding arm of the T cell engaging molecule further comprises a light chain comprising a VL domain comprising a VL- CDR1 selected from SEQ ID Nos: 4, 12, 20, 100, 108, 130, 138, and 146; a VL-CDR2 selectedfrom SEQ ID NO: 5, 13, 21, 101, 109, 131, 139, and 147; a VL-CDR3 selected from SEQ ID Nos: 6, 14, 22, 102, 110, 132, 140, and 148; and a light chain constant domain.

[0381] In some aspects, the T cell engaging molecule further comprises a T cell binding arm that binds CD3 and comprises a heavy chain comprising a VH domain comprising a VH- CDR1 selected from SEQ ID Nos: 36, 40, and 44; a VH-CDR2 selected from SEQ ID NO: 37, 41, and 45; a VH-CDR3 selected from SEQ ID NO: 38, 42, and 46; and a CHI domain. In some aspects, the T cell binding arm further comprises a light chain comprising a VL comprising a VL- CDR1 selected from SEQ ID Nos: 27 and 31; a VL-CDR2 selected from SEQ ID Nos: 28 and 32; a VL-CDR3 selected from SEQ ID Nos: 29 and 33; and a light chain constant domain. In some aspects, the T cell engaging molecule further comprises an Fc domain comprising a first Fc region and a second Fc region, each Fc region comprising a CH2 domain and a CH3 domain; further comprising at least one modification to promote heterodimerization.

[0382] In some aspects, the T cell engaging molecule further comprises a second antigen binding arm that binds STEAP2 and comprises a heavy chain comprising a VH domain comprising a VH-CDR1 selected from SEQ ID Nos: 1, 9, 17, 103, 111, 127, 135, and 143; a VH-CDR2 selected from SEQ ID Nos: 2, 10, 18, 104, 112, 128, 136, and 144; a VH-CDR3 selected from SEQ ID Nos: 3, 11, 19, 94, 96, 98, 105, 113, 129, 137, and 145; and a CHI domain. In some aspects, the second antigen binding arm of the T cell engaging molecule further comprises a light chain comprising a VL comprising a VL-CDR1 selected from SEQ ID Nos: 4, 12, 20, 100, 108, 130, 138, and 146; a VL-CDR2 selected from SEQ ID NO: 5, 13, 21, 101, 109, 131, 139, and 147; a VL-CDR3 selected from SEQ ID Nos: 6, 14, 22, 102, 110, 132, 140, and 148; and a light chain constant domain.

[0383] In some aspects, one of the CH3 domains of the Fc region of the T cell engaging molecule comprises a knob mutation, and the other CH3 domain comprises a hole mutation.

[0384] In some aspects, a CHI domain and a light chain constant domain of one or more of each of an antigen binding arm and a T cell binding arm of the T cell engaging molecule further comprise a charge pair substitution comprising a first charged amino acid substitution in the CHI and a second charged amino acid substitution in the light chain constant domain, wherein the first charged amino acid substitution and the second charged amino acid substitution have an opposite charge.

[0385] In some aspects, a light chain constant domain of one or more of each of an antigen binding arm and a T cell binding arm is a lambda light chain constant domain (CLX) and the charge pair is a lambda charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine. In some aspects, the charged amino acids of a lambda charge pair are located at one or more of the following positions:(i) position 117 in the CLX and position 141 in the CHI domain;(ii) position 117 in the CLX and position 185 in the CHI domain;(iii) position 119 in the CLX and position 128 in the CHI domain;(iv) position 134 in the CLX and position 128 in the CHI domain;(v) position 134 in the CLX and position 145 in the CHI domain;(vi) position 134 in the CLX and position 183 in the CHI domain;(vii) position 136 in the CLX and position 185 in the CHI domain;(viii) position 178 in the CLX and position 173 in the CHI domain; and / or(ix) position 117 in the CLX and position 187 in the CHI domain, wherein the numbering is according to the EU index.

[0386] In some aspects, a light chain constant domain of one or more of each of an antigen binding arm and a T cell binding arm is a lambda light chain constant domain (CLX) and the charge pair is a lambda charge pair, wherein:(c) the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is threonine;(ii) the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is arginine and the chargedamino acid at position 185 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is threonine;(iii) the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is threonine;(iv) the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is threonine;(v) the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is glutamic acid; the charged amino acid atposition 134 is lysine and the charged amino acid at position 145 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is threonine;(vi) the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is threonine;(vii) the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is threonine;(viii) the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is serine; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is threonine; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is serine; or the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is threonine; and / or(ix) the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid atposition 187 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is threonine.

[0387] In some aspects, a light chain constant domain of one or more of each an antigen binding arm and a T cell binding arm of the T engaging molecule is a kappa light chain constant domain (CLK) and the charge pair is a kappa charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine, wherein the kappa charge pair is located at position 133 in the CLK and position 183 in the CHI.

[0388] In some aspects, a light chain constant domain of one or more of each an antigen binding arm and a T cell binding arm of the T engaging molecule is a kappa light chain constant domain (CLK) and the charge pair is a kappa charge pair wherein the charged amino acid at position 133 is glutamic acid and the charged amino acid at position 183 is lysine; or the charged amino acid at position 133 is lysine and the charged amino acid at position 183 is glutamic acid.

[0389] In some aspects, a light chain constant domain of a T cell binding arm is a CLA. and the charge pair is a lambda charge pair as described herein and the light chain constant domain of a first and / or second antigen binding domain is a lambda or a kappa charge pair and the first antigen binding arm comprises a charged amino acid in the CHI that is of a same charge as a charged amino acid in the CHI domain of the second antigen binding arm.

[0390] In some aspects, a light chain constant domain of a T cell binding arm is a CLA and the charge pair is a lambda charge pair as described herein and the light chain constant domain of a first and a second antigen binding arm is a kappa charge pair and a charged amino acid in the CHI domain of the first antigen binding arm is of a same charge as a charged amino acid in the CHI domain of the second antigen binding arm.

[0391] In some aspects, a CHI domain of an antigen binding arm or a T cell binding arm is capable of being linked to a light chain constant domain through an engineered disulfide link.

[0392] In some aspects, a CHI domain that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises (i) a substitution of a native cysteine to a non-cysteine amino acid and (ii) a substitution of a native non-cysteine amino acid to a cysteine; and the light chain constant domain comprises (i) a substitution of a native cysteine to a non-cysteine amino acid and (ii) a substitution of a native non-cysteine amino acid to a cysteine; wherein the substituted cysteine of the light chain constant domain and the substituted cysteine of the CHI domain can form a disulfide bond.

[0393] In some aspects, a CHI domain that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises (i) a substitution of a native cysteine to a non-cysteine amino acid at position 220, and (ii) a substitution of a native non- cysteine amino acid to a cysteine at position 126; and the light chain constant domain comprises (i) a substitution of a native cysteine to a non-cysteine amino acid at position 212, and (ii) a substitution of a native non-cysteine amino acid to a cysteine at position 122, wherein the cysteine at position 126 of the CHI domain and the cysteine at position 122 of the light chain constant domain can form a disulfide bond; wherein the numbering is according to the EU index.

[0394] In some aspects, a CHI domain that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises (i) a substitution of a native cysteine to a non-cysteine amino acid at position 220, and (ii) a substitution of a native non- cysteine amino acid to a cysteine at position 126; and the light chain constant domain comprises (i) a substitution of a native cysteine to a non-cysteine amino acid at position 214, and (ii) a substitution of a native non-cysteine amino acid to a cysteine at position 121, wherein the cysteine at position 126 of the CHI domain and the cysteine at position 121 of the light chain constant domain can form a disulfide bond; wherein the numbering is according to the EU index.

[0395] In some aspects, an antigen binding arm of a T cell engaging molecule comprises a VH domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149.

[0396] In some aspects, an antigen binding arm of a T cell engaging molecule comprises a heavy chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, atleast about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 90.

[0397] In some aspects, an antigen binding arm of a T cell engaging molecule comprises a heavy chain comprising a VH domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149 and a CHI domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 90.

[0398] In some aspects, an antigen binding arm of the T cell engaging molecule comprises a VL domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 8, 16, 24, 107, 115, 134, 142, and 150.

[0399] In some aspects, an antigen binding arm of a T cell engaging molecule comprises a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 63.

[0400] In some aspects, an antigen binding arm of a T cell engaging molecule comprises a light chain comprising a VL domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 8, 16, 24, 107, 115, 134, 142, and 150 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 63.

[0401] In some aspects, an antigen binding arm of a T cell engaging molecule comprises a VH domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, orat least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149.

[0402] In some aspects, an antigen binding arm of a T cell engaging molecule comprises a heavy chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 88.

[0403] In some aspects, an antigen binding arm of a T cell engaging molecule comprises a heavy chain comprising a VH domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 7, 15, 23 ,95, 97, 99, 106, 114, 133, 141, and 149 and a CHI domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 88.

[0404] In some aspects, a T cell binding arm of a T cell engaging molecule comprises a VH domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 39, 43, and 47.

[0405] In some aspects, a T cell binding arm of a T cell engaging molecule comprises a heavy chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 79.

[0406] In some aspects, a T cell binding arm of a T cell engaging molecule comprises a heavy chain comprising a VH domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 39, 43, and 47 and a heavy chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 79.

[0407] In some aspects, a T cell binding arm of the T cell engaging molecule comprises a VL domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 30 and 34.

[0408] In some aspects, a T cell binding arm of a T cell engaging molecule comprises a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 61.

[0409] In some aspects, a T cell binding arm of a T cell engaging molecule comprises a light chain comprising a VL domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 30 and 34 and a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 61.

[0410] In some aspects, a T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 25. In some aspects, a T cell engaging molecule comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 25.

[0411] In some aspects, a T cell engaging molecule comprises a light chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 116. In some aspects, a T cell engaging molecule comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 116.

[0412] In some aspects, a T cell engaging molecule comprises a light chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 117. In some aspects, a T cell engaging molecule comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 117.

[0413] In some aspects, a T cell engaging molecule comprises a light chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 118. In some aspects, a T cell engaging molecule comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 118.

[0414] In some aspects, a T cell engaging molecule comprises a light chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to the amino acid sequence set forth in SEQ ID NO: 119. In some aspects, a T cell engaging molecule comprises a light chain comprising the amino acid sequence set forth in SEQ ID NO: 119.

[0415] In some aspects, a T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 35. In some aspects, a T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 81. In some aspects, a T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 88.

[0416] In some aspects, a T cell engaging molecule comprises an amino acid sequence set forth in SEQ ID NO: 25. In some aspects, a T cell engaging molecule comprises an amino acidsequence set forth in SEQ ID NO: 35. In some aspects, a T cell engaging molecule comprises an amino acid sequence set forth in SEQ ID NO: 81. In some aspects, a T cell engaging molecule comprises an amino acid sequence set forth in SEQ ID NO: 88.

[0417] In some aspects, a T cell engaging molecule comprises the amino acid sequences set forth in SEQ ID NO: 25, 26, 35, 81 and 92.VIII. Trivalent Trispecific T Cell Engaging Molecules

[0418] The present disclosure provides trivalent trispecific T cell engaging molecules. Trivalent T cell engaging molecules as described herein are capable of binding three different epitopes, either on the same or, in some aspects, different antigens. In some aspects, the trivalent T cell binding molecules comprise at least one antigen binding arm and at least two different T cell binding arms. In some aspects, the antigen binding arm is referred to herein as a “first antigen binding arm”, and the T cell binding arms are referred herein as a “first T cell binding arm” and a “second T cell binding arm”. According to the present disclosure, an “antigen binding arm” comprises a heavy chain comprising a VH domain and CHI domain and a light chain comprising a VL domain and a light chain constant domain, where the light chain constant domain is disulfide linked to the CHI domain. In some aspects, a “T cell binding arm” comprises a heavy chain comprising a VH domain and CHI domain and a light chain comprising a VL domain and a light chain constant domain, where the light chain constant domain is disulfide linked to the CHI domain. In some aspects, a T cell binding arm comprises only a VH domain.

[0419] In some aspects, an antigen binding arm and / or at least one T cell binding arm in the trivalent T cell engaging molecule further comprise an Fc region. In some aspects, an antigen binding arm and / or a T cell binding arm in the trivalent T cell engaging molecule comprise complete heavy chains (i.e. a VH domain, CHI domain, hinge region, CH2 domain and CH3 domain).

[0420] In some aspects, a trivalent T cell engaging molecule comprises (i) an antigen binding arm comprising a heavy chain comprising a VH and a heavy chain constant region comprising a CHI, CH2, and CH3 domain, and a light chain comprising a VL and a light chain constant domain; (ii) a first T cell binding arm comprising a heavy chain comprising a VH and a heavy chain constant region comprising a CHI, CH2, and CH3 domain, and a light chain comprising a VL and a light chain constant domain; and (iii) a second T cell binding armcomprising a heavy chain comprising a VH and a CHI domain and a light chain comprising a VL and a light chain constant domain; wherein the heavy chain of the second T cell binding arm is attached to the heavy chain of the first T cell binding arm through a peptide linker. An exemplary trivalent T cell engaging molecule is shown in Figure 1C.

[0421] In some aspects, a light chain of an antigen binding arm is disulfide linked to a heavy chain of the antigen binding arm in the trivalent T cell engaging molecule via a native interchain disulfide bond (e.g., a disulfide bond present in an IgG antibody). In some aspects, a light chain of an antigen binding arm is disulfide linked to a heavy chain of the antigen binding arm in the trivalent T cell engaging molecule via an engineered disulfide bond. In some aspects, a light chain of a first and / or second T cell binding arm is disulfide linked to a heavy chain of the first and / or second T cell binding arm in the trivalen- 105 -ngagingl engaging molecule via a native inter-chain disulfide. In some aspects, a light chain of a first and / or second T cell binding arm is disulfide linked to a heavy chain of the first and / or second T cell binding arm in the T cell engaging molecule via an engineered disulfide bond.

[0422] In some aspects, a heavy chain of an antigen binding arm is attached to a heavy chain of another antigen binding arm via a peptide linker. In some aspects, a heavy chain of an antigen binding arm is attached to a T cell binding arm via a peptide linker. In some aspects, a peptide linker consists of 5 to 100 amino acids, 5 to 50 amino acids, 5 to 25 amino acids, or 5 to 15 amino acids. In some aspects, a peptide linker is formed mainly from glycine and serine amino acid residues and in some aspects comprises the amino acid sequences GGGGS or SGGGGS. In some aspects, the peptide linker comprises or consists of SEQ ID NO: 89. In some aspects, the linker comprises from 1 to about 10 copies of SEQ ID NO: 89. In some aspects, the linker comprises 2 copies of SEQ ID NO: 89.

[0423] In some aspects, a trivalent T cell engaging molecule comprises (a) at least one antigen binding arm that binds STEAP2 and comprises a heavy chain comprising a VH domain and a CHI domain; and a light chain comprising a VL and a light chain constant domain ; (b) at least one T cell binding arm comprising a heavy chain comprising a VH domain and a CHI domain; a light chain comprising a VL domain and a light chain constant domain; and (c) an Fc domain comprising a first Fc region and a second Fc region, each Fc region comprising a CH2 domain and a CH3 domain; further comprising at least one modification to promote heterodimerization.

[0424] In some aspects, a trivalent T cell engaging molecule comprises (i) at least one antigen binding arm that binds an epitope on STEAP2, (ii) at least one T cell binding arm that binds CD3, and (iii) at least one T cell binding arm that binds CD8.

[0425] In some aspects, one of the CH3 domains of the Fc region of the trivalent T cell engaging molecule comprises a knob mutation, and the other CH3 domain comprises a hole mutation.

[0426] In some aspects, a CHI domain and a light chain constant domain of one or more of each of an antigen binding arm and a T cell binding arm of the trivalent T cell engaging molecule further comprise a charge pair substitution comprising a first charged amino acid substitution in the CHI and a second charged amino acid substitution in the light chain constant domain, wherein the first charged amino acid substitution and the second charged amino acid substitution have an opposite charge.

[0427] In some aspects, a light chain constant domain of one or more of each of an antigen binding arm and a T cell binding arm of the trivalent T engaging molecule is a lambda light chain constant domain (CLX) and the charge pair is a lambda charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine. In some aspects, the charged amino acids of a lambda charge pair are located at one or more of the following positions:(i) position 117 in the CLX and position 141 in the CHI domain;(ii) position 117 in the CLX and position 185 in the CHI domain;(iii) position 119 in the CLX and position 128 in the CHI domain;(iv) position 134 in the CLX and position 128 in the CHI domain;(v) position 134 in the CLX and position 145 in the CHI domain;(vi) position 134 in the CLX and position 183 in the CHI domain;(vii) position 136 in the CLX and position 185 in the CHI domain;(viii) position 178 in the CLX and position 173 in the CHI domain; and / or(ix) position 117 in the CLX and position 187 in the CHI domain, wherein the numbering is according to the EU index.

[0428] In some aspects, a light chain constant domain of one or more of each of an antigen binding arm and a T cell binding arm of the trivalent T engaging molecule is a lambda light chain constant domain (CLX) and the charge pair is a lambda charge pair, wherein:(c) the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is threonine;(ii) the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is threonine;(iii) the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is threonine;(iv) the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 134 is arginine and thecharged amino acid at position 128 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is threonine;(v) the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is threonine;(vi) the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is threonine;(vii) the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid atposition 136 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is threonine;(viii) the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is serine; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is threonine; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is serine; or the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is threonine; and / or(ix) the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is threonine.

[0429] In some aspects, a light chain constant domain of one or more of each an antigen binding arm and a T cell binding arm of the trivalent T engaging molecule is a kappa light chain constant domain (CLK) and the charge pair is a kappa charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine, wherein the kappa charge pair is located at position 133 in the CLK and position 183 in the CHI.

[0430] In some aspects, a light chain constant domain of one or more of each an antigen binding arm and a T cell binding arm of the trivalent T engaging molecule is a kappa light chain constant domain (CLK) and the charge pair is a kappa charge pair wherein the charged amino acid at position 133 is glutamic acid and the charged amino acid at position 183 is lysine; or the charged amino acid at position 133 is lysine and the charged amino acid at position 183 is glutamic acid.

[0431] In some aspects, a light chain constant domain of a T cell binding arm of the trivalent T engaging molecule is a CLX and the charge pair is a lambda charge pair as described herein and the light chain constant domain of an antigen binding arm and a second T cell binding arm of the trivalent T engaging molecule is a lambda or a kappa charge pair and the antigen binding arm comprises a charged amino acid in the CHI domain that is of a same charge as a charged amino acid in the CHI domain of the second T cell binding arm.

[0432] In some aspects, a light chain constant domain of a T cell binding arm is a CLX and the charge pair is a lambda charge pair as described herein and the light chain constant domain of an antigen binding domain and a second T cell binding arm is a kappa charge pair and a charged amino acid in the CHI domain of the antigen binding arm is of a same charge as a charged amino acid in the CHI domain of the second T cell binding arm.

[0433] In some aspects, a CHI domain of an antigen binding arm or a T cell binding arm of a trivalent T cell engaging molecule is capable of being linked to a light chain constant domain through an engineered disulfide link.

[0434] In some aspects, a CHI domain that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises (i) a substitution of a native cysteine to a non-cysteine amino acid and (ii) a substitution of a native non-cysteine amino acid to a cysteine; and the light chain constant domain comprises (i) a substitution of a native cysteine to a non-cysteine amino acid and (ii) a substitution of a native non-cysteine amino acid to a cysteine; wherein the substituted cysteine of the light chain constant domain and the substituted cysteine of the CHI domain can form a disulfide bond.

[0435] In some aspects, a CHI domain that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises (i) a substitution of a native cysteine to a non-cysteine amino acid at position 220, and (ii) a substitution of a native non- cysteine amino acid to a cysteine at position 126; and the light chain constant domain comprises (i) a substitution of a native cysteine to a non-cysteine amino acid at position 212, and (ii) a substitution of a native non-cysteine amino acid to a cysteine at position 122, wherein the cysteine at position 126 of the CHI domain and the cysteine at position 122 of the light chain constant domain can form a disulfide bond; wherein the numbering is according to the EU index.

[0436] In some aspects, a CHI domain that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises (i) a substitution of a nativecysteine to a non-cysteine amino acid at position 220, and (ii) a substitution of a native noncysteine amino acid to a cysteine at position 126; and the light chain constant domain comprises (i) a substitution of a native cysteine to a non-cysteine amino acid at position 214, and (ii) a substitution of a native non-cysteine amino acid to a cysteine at position 121, wherein the cysteine at position 126 of the CHI domain and the cysteine at position 121 of the light chain constant domain can form a disulfide bond; wherein the numbering is according to the EU index.

[0437] In some aspects, a trivalent T cell engaging molecule comprises an antigen binding arm that binds STEAP2 and comprises a heavy chain comprising a VH domain comprising a VH- CDR1 selected from SEQ ID Nos: 1, 9, 17, 103, 111, 127, 135, and 143; a VH-CDR2 selected from SEQ ID Nos: 2, 10, 18, 104, 112, 128, 136, and 144; a VH-CDR3 selected from SEQ ID Nos: 3, 11,19, 94, 96, 98, 105, and 113; and a CHI domain. In some aspects, the antigen binding arm of the trivalent T cell engaging molecule further comprises a light chain comprising a VL domain comprising a VL-CDR1 selected from SEQ ID Nos: 4, 12, 20, 100, 108, 130, 138, and 146; a VL-CDR2 selected from SEQ ID Nos: 5, 13, 21, 101, 109, 131, 139, and 147; a VL-CDR3 selected from SEQ ID Nos: 6, 14, 22, 102, 110, 132, 140, and 148; and a light chain constant domain.

[0438] In some aspects, a trivalent T cell engaging molecule comprises an antigen binding arm that binds STEAP2 and comprises a heavy chain comprising a VH domain comprising an amino acid sequence acid having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149. In some aspects, a trivalent T cell engaging molecule comprises an antigen binding arm that binds STEAP2 and comprises a heavy chain comprising a VH domain comprising an amino acid sequence selected from SEQ ID Nos: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149.

[0439] In some aspects, a trivalent T cell engaging molecule comprises an antigen binding arm that binds STEAP2 and comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 91. In some aspects, a trivalent T cell engaging moleculecomprises an antigen binding arm that binds STEAP2 and comprises a heavy chain comprising an amino acid sequence set forth in SEQ ID NO: 91.

[0440] In some aspects, a trivalent T cell engaging molecule comprises an antigen binding arm that binds STEAP2 and comprises a heavy chain comprising a VH domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149 and a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 91. In some aspects, a trivalent T cell engaging molecule comprises an antigen binding arm that binds STEAP2 and comprises a heavy chain comprising a VH domain comprising an amino acid sequence selected from SEQ ID Nos: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149 and a heavy chain comprising an amino acid sequence set forth in SEQ ID NO: 91.

[0441] In some aspects, the trivalent T cell engaging molecule further comprises at least one T cell binding arm that binds CD3 and comprises a heavy chain comprising a VH domain comprising a VH-CDR1 selected from SEQ ID Nos: 36, 40, and 44; a VH-CDR2 selected from SEQ ID Nos: 37, 41, and 45; a VH-CDR3 selected from SEQ ID Nos: 38, 42, and 46; and a CHI domain. In some aspects, the T cell binding arm further comprises a light chain comprising a VL comprising a VL-CDR1 selected from SEQ ID Nos: 27 and 31; a VL-CDR2 selected from SEQ ID Nos: 28 and 32; a VL-CDR3 selected from SEQ ID Nos: 29 and 33; and a light chain constant domain. In some aspects, the trivalent T cell engaging molecule further comprises an Fc domain comprising a first Fc region and a second Fc region, each Fc region comprising a CH2 domain and a CH3 domain; further comprising at least one modification to promote heterodimerization.

[0442] In some aspects, the at least one T cell binding arm that binds CD3 comprises a VH domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 39, 43, and 47. In some aspects, the at least one T cell binding arm that binds CD3 comprises a VH domain comprising an amino acid sequence selected from SEQ ID Nos: 39, 43, and 47.

[0443] In some aspects, the at least one T cell binding arm that binds CD3 comprises a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 79. In some aspects, the at least one T cell binding arm that binds CD3 comprises a heavy chain comprising an amino acid sequence set forth in SEQ ID NO: 79.

[0444] In some aspects, the trivalent T cell engaging molecule comprises a T cell binding arm that binds CD3 and comprises a VH domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 39, 43, and 47 and a heavy chain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 79. In some aspects, the trivalent T cell engaging molecule comprises a T cell binding arm that binds CD3 and comprises a VH domain comprising an amino acid sequence selected from SEQ ID Nos: 39, 43, and 47 and a heavy chain comprising an amino acid sequence set forth in SEQ ID NO: 79.

[0445] In some aspects, the trivalent T cell engaging molecule further comprises at least one T cell binding arm that binds CD8 and comprises a heavy chain comprising a VH domain comprising a VH-CDR1 selected from SEQ ID Nos: 48 and 84; a VH-CDR2 selected from SEQ ID Nos: 49 and 85; a VH-CDR3 selected from SEQ ID Nos: 50 and 86; and a CHI domain. In some aspects, the T cell binding arm further comprises a light chain comprising a VL comprising a VL-CDR1 set forth in SEQ ID NO: 51; a VL-CDR2 set forth in SEQ ID NO: 52; a VL-CDR3 set forth in SEQ ID NO: 53; and a light chain constant domain. In some aspects, the trivalent T cell engaging molecule further comprises an Fc domain comprising a first Fc region and a second Fc region, each Fc region comprising a CH2 domain and a CH3 domain; further comprising at least one modification to promote heterodimerization.

[0446] In some aspects, the at least one T cell binding arm that binds CD8 comprises a VH domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 56. In someaspects, the at least one T cell binding arm that binds CD8 comprises a VH domain comprising an amino acid sequence set forth in SEQ ID NO: 56.

[0447] In some aspects, the at least one T cell binding arm that binds CD8 comprises a CHI domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 57. In some aspects, the at least one T cell binding arm that binds CD8 comprises a CHI domain comprising an amino acid sequence set forth in SEQ ID NO: 57.

[0448] In some aspects, the trivalent T cell engaging molecule comprises a T cell binding arm that binds CD8 and comprises a VH domain comprising an amino acid having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 56 and a CHI domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about ...

Claims

WHAT IS CLAIMED IS:

1. A T cell engaging molecule comprising:(a) an antigen binding arm that binds an epitope on human six transmembrane epithelial antigen of prostate-2 (STEAP2) and comprises a heavy chain comprising a heavy chain variable domain (VH) comprising a variable heavy chain complementarity determining region 1 (VH- CDR1) selected from SEQ ID NOs: 1, 9, 17, 103, 111, 127, 135, and 143; a VH-CDR2 selected from SEQ ID NOs: 2, 10, 18, 104, 112, 128, 136, and 144; a VH-CDR3 selected from SEQ ID NOs: 3, 11, 19, 94, 96, 98, 105, 113, 129, 137, and 145; a heavy chain CHI domain; and a light chain comprising a light chain variable domain (VL) comprising a variable light chain complementarity determining region 1 (VL-CDR1) selected from SEQ ID NOs: 4, 12, 20, 100, 108, 130, 138, and 146; a VL-CDR2 selected from SEQ ID NOs: 5, 13, 21, 101, 109, 131, 139, and 147; a VL-CDR3 selected from SEQ ID NOs: 6, 14, 22, 102, 110, 132, 140, and 148; and a light chain constant domain;(b) a first T cell binding arm that binds to cluster of differentiation 3 (CD3) comprising a heavy chain comprising a heavy chain variable domain (VH) comprising a VH-CDR1 selected from SEQ ID NOs: 36, 40, and 44; a VH-CDR2 selected from SEQ ID NOs: 37, 41, and 45; a VH-CDR3 selected from SEQ ID NOs: 38, 42, and 46; and a heavy chain CHI domain; and a light chain comprising a light chain variable domain (VL) comprising a VL-CDR1 selected from SEQ ID NOs: 27 and 31; a VL-CDR2 selected from SEQ ID NOs: 28 and 32; a VL-CDR3 selected from SEQ ID NOs: 29 and 33; and a light chain constant domain; and(c) a Fc domain, comprising a first Fc region and a second Fc region, each Fc region comprising a CH2 domain and a CH3 domain; said Fc domain further comprising at least one modification to promote heterodimerization.

2. A trivalent T cell engaging molecule comprising the T cell engaging molecule according to claim 1, further comprising (d) a second T cell binding arm that binds to cluster of differentiation 8 (CD8) and comprises a heavy chain comprising a heavy chain variable domain (VH) comprising a VH-CDR1 set forth in SEQ ID NO: 48, a VH-CDR2 set forth in SEQ ID NO: 49, and a VH-CDR3 set forth in SEQ ID NO: 50, and a heavy chain CHIdomain; and a light chain comprising a light chain variable domain (VL) comprising a VL- CDR1 set forth in SEQ ID NO: 51, a VL-CDR2 set forth in SEQ ID NO: 52, and a VL- CDR3 set forth in SEQ ID NO: 53, and a light chain constant domain.

3. The trivalent T cell engaging molecule according to claim 2, wherein the heavy chain of the second T cell binding arm is attached to the heavy chain of the first T cell binding arm through a linker.

4. The trivalent T cell engaging molecule according to claim 2, wherein the heavy chain of the second T cell binding arm is attached to the heavy chain of the antigen binding arm through a linker.

5. The trivalent T cell engaging molecule according to claim 3 or 4, wherein the linker comprises the amino acid sequence of SEQ ID NO: 89.

6. The trivalent T cell engaging molecule according to any one of claims 3 to 5, wherein the linker comprises from 1 to about 10 copies of SEQ ID NO: 89.

7. The trivalent T cell engaging molecule according to any one of claims 3 to 6, wherein the linker comprises 2 copies of SEQ ID NO: 89.

8. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 7, wherein one of the two CH3 domains comprises a knob mutation, and the other of the two CH3 domains comprises a hole mutation.

9. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 8, wherein the CHI domain and the light chain constant domain of one or more of each of the (a) antigen binding arm, (b) the first T cell binding arm, and (d) the second T cell binding arm further comprises a charge pair substitution comprising a first charged amino acid substitution in the CHI domain and a second charged amino acid substitution in the light chain constant domain, wherein the first charged amino acid substitution and the second charged amino acid substitution have an opposite charge.

10. The T cell engaging molecule or trivalent T cell engaging molecule according to claim 9, wherein the light chain constant domain of one or more of each of (a), (b), and (d) is a lambda light chain constant domain (CLX) and wherein the charge pair is a lambda charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine, wherein the numbering is according to the EU index and wherein the charged amino acids of the lambda charge pair are located at one or more of the following positions:(i) position 117 in the CLX and position 141 in the CHI domain;(ii) position 117 in the CLX and position 185 in the CHI domain;(iii) position 119 in the CLX and position 128 in the CHI domain;(iv) position 134 in the CLX and position 128 in the CHI domain;(v) position 134 in the CLX and position 145 in the CHI domain;(vi) position 134 in the CLX and position 183 in the CHI domain;(vii) position 136 in the CLX and position 185 in the CHI domain;(viii) position 178 in the CLX and position 173 in the CHI domain; and / or(ix) position 117 in the CLX and position 187 in the CHI domain.

11. The T cell engaging molecule or trivalent T cell engaging molecule according to claim 10, wherein (i) the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position141 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is threonine;(ii) the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is threonine;(iii) the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is threonine;(iv) the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is aspartic acid; the chargedamino acid at position 134 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is threonine;(v) the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is threonine;(vi) the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is threonine;(vii) the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is threonine; the chargedamino acid at position 136 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is threonine;(viii) the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is serine; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is threonine; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is serine; or the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is threonine; and / or(ix) the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is threonine.

12. The T cell engaging molecule or trivalent T cell engaging molecule according to claim 9, wherein the light chain constant domain of one or more of each of (a), (b), and (d) is a kappa light chain constant domain (CLK) and wherein the charge pair is a kappa charge pair comprising a positively charged amino acid residue selected from arginine, lysine orhistidine, and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine, wherein the numbering is according to the EU index and wherein the kappa charge pair is located at position 133 in the CLK and position 183 in the CHI domain.

13. The T cell engaging molecule or trivalent T cell engaging molecule according to claim 12, wherein the charged amino acid at position 133 is glutamic acid and the charged amino acid at position 183 is lysine; or the charged amino acid at position 133 is lysine and the charged amino acid at position 183 is glutamic acid.

14. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 13, wherein the light chain constant domain of one of (a), (b), and (d) is a CLX and wherein the charge pair is a lambda charge pair and the light chain constant domain of a second and a third of (a), (b), and (d) is a CLX or a CLK and wherein the charge pair is a lambda or a kappa charge pair and the second of (a), (b), and (d) comprises a charged amino acid in the CHI domain of a same charge as a charged amino acid in the CHI domain of the third of (a), (b), and (d).

15. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 14, wherein the light chain constant domain of one of (a), (b), and (d) is a CLX and wherein the charge pair is a lambda charge pair and the light chain constant domain of a second and a third of (a), (b), and (d) is a kappa charge pair and the second of (a), (b), and (d) comprises a charged amino acid in the CHI domain of a same charge as a charged amino acid in the CHI domain of the third of (a), (b), and (d).

16. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 15, wherein the CHI domain of (a), (b), and / or (d) is capable of being linked to the light chain constant domain through an engineered disulfide link.

17. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 16, wherein the CHI domain of (b) and (d) is capable of being linked to the light chain constant domain through an engineered disulfide link and the CHI domain of (a) is linked to the light chain constant domain through a native disulfide link.

18. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claim 16 or 17, wherein the CHI domain that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises(i) a substitution of a native cysteine to a non-cysteine amino acid,(ii) a substitution of a native non-cysteine amino acid to a cysteine; and the light chain constant domain comprises(i) a substitution of a native cysteine to a non-cysteine amino acid,(ii) a substitution of a native non-cysteine amino acid to a cysteine; and wherein the substituted cysteine of the light chain constant domain and the substituted cysteine of the CHI domain can form a disulfide bond.

19. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 16 to 18, wherein the CHI domain that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 220,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 126; and the light chain constant domain comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 212,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 122, wherein the cysteine at position 126 of the CHI domain and the cysteine at position 122 of the light chain constant domain can form a disulfide bond; wherein the numbering is according to the EU index.

20. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 16 to 18 wherein the CHI domain that is capable of being linked to the light chain constant domain through an engineered disulfide link comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 220,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 126; and the light chain constant domain comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 214,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 121, wherein the cysteine at position 126 of the CHldomain and the cysteine at position 121 of the light chain constant domain can form a disulfide bond; wherein the numbering is according to the EU index.

21. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 20, wherein the antigen binding arm comprises a VH comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149.

22. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 21, wherein the antigen binding arm is attached to the Fc domain and comprises a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 66, 67, 69, 72, 73, 76, 80, 82, 88, and 91.

23. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 22, wherein the antigen binding arm comprises a VL comprising an amino acidsequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 8, 16, 24, 107, 115, 134, 142, and 150.

24. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 23, wherein the antigen binding arm comprises a light chain constant domain comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NOs: 63.

25. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 24, wherein the VL of the T cell binding arm of the T cell engaging molecule or the VL of the first or second T cell binding arm of the trivalent T cell engaging molecule comprises a VL-CDR1 selected from SEQ ID NOs: 27 and 31; a VL-CDR2 selected from SEQ ID NOs: 28 and 32; and a VL-CDR3 selected from SEQ ID NOs: 29 and 33; and the VH comprises a VH-CDR1 selected from SEQ ID NOs: 36, 40, and 44; a VH-CDR2 selected from SEQ ID NOs: 37, 41 and 45; and a VH-CDR3 selected from SEQ ID NOs: 38, 42, and 46.

26. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 25, wherein the VL of the T cell binding arm of the T cell engaging molecule or the VL of the first or second T cell binding arm of the trivalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30 or 34.

27. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 26, wherein the light chain constant domain of the T cell engaging molecule or the light chain constant domain of the first or second T cell binding arm of the trivalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at leastabout 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 60 or 61.

28. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 27, wherein the VH of the T cell binding arm of the T cell engaging molecule or the VH of the first or second T cell binding arm of the trivalent T cell engaging molecule comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NOs: 39, 43, or 47.

29. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 28, wherein the heavy chain of the T cell binding arm of the T cell engaging molecule or the first or second T cell binding arm of the trivalent T cell engaging molecule is attached to the Fc domain and comprises a heavy chain constant region comprising an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID Nos: 66, 67, 69, 74, 75, 77, 78, and 79.

30. The trivalent T cell engaging molecule according to any one of claims 1 to 29, wherein the VH of the first or second T cell binding arm comprises a VH-CDR1 set forth in SEQ ID NO: 48; a VH-CDR2 set forth in SEQ ID NO: 49; a VH-CDR3 set forth in SEQ ID NO: 50; and the VL comprises a VL-CDR1 set forth in SEQ ID NO: 51; a VL-CDR2 set forth in SEQ ID NO: 52; and a VL-CDR3 set forth in SEQ ID NO: 53.

31. The trivalent T cell engaging molecule according to any one of claims 1 to 30, wherein the VL of the first or second T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 54.

32. The trivalent T cell engaging molecule according to any one of claims 1 to 31, wherein the constant light chain domain of the first or second T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 64.

33. The trivalent T cell engaging molecule according to any one of claims 1 to 32, wherein the VH of the first or second T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 56.

34. The trivalent T cell engaging molecule according to any one of claims 1 to 33, wherein the heavy chain constant domain of the first or second T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NO: 57, 66, 67, 69, 74, 75, 77, 78, and 79.

35. The T cell engaging molecule or trivalent T cell engaging molecule according to any one of claims 1 to 34, wherein the antigen binding arm binds an epitope on an extracellular loop of STEAP2.

36. The T cell engaging molecule according to any one of claims 1 to 35, wherein the T cell engaging molecule comprises SEQ ID NOs: 25, 26, 35, 81 and 92.

37. The trivalent T cell engaging molecule according to any one of claims 1 to 35, wherein the trivalent T cell engaging molecule comprises SEQ ID NOs: 25, 26, 35, 55 and 58.

38. A trivalent T cell engaging molecule comprising:(a) a first antigen binding arm and a second antigen binding arm that each bind an epitope on human six transmembrane epithelial antigen of prostate-2 (STEAP2) and each comprise a heavy chain comprising a heavy chain variable domain (VH) comprising a variable heavy chaincomplementarity determining region 1 (VH-CDR1) selected from SEQ ID NOs: 1, 9, 17, 103, 111, 127, 135, and 143; a VH-CDR2 selected from SEQ ID NOs: 2, 10, 18, 104, 112, 128, 136, and 144; a VH-CDR3 selected from SEQ ID NOs: 3, 11, 19, 94, 96, 98, 105, 113, 129, 137, and 145; a heavy chain CHI domain; and a light chain comprising a light chain variable domain (VL) comprising a variable light chain complementarity determining region 1 (VL-CDR1) selected from SEQ ID NOs: 4, 12, 20, 100, 108, 130, 138, and 146; a VL-CDR2 selected from SEQ ID NOs: 5, 13, 21, 101, 109, 131, 139, and 147; a VL-CDR3 selected from SEQ ID NOs: 6, 14, 22, 102, 110, 132, 140, and 148; and a light chain constant domain;(b) a first T cell binding arm that binds to cluster of differentiation 3 (CD3) and comprises a heavy chain comprising a VH comprising a VH-CDR1 selected from SEQ ID NOs: 36, 40, and 44; a VH-CDR2 selected from SEQ ID NOs: 37, 41, and 45; a VH-CDR3 selected from SEQ ID NOs: 38, 42, and 46; and a heavy chain CHI domain; and a light chain comprising a VL comprising a VL-CDR1 selected from SEQ ID NOs: 27 and 31; a VL-CDR2 selected from SEQ ID NOs: 28 and 32; a VL-CDR3 selected from SEQ ID NOs: 29 and 33; and a light chain constant domain; and(c) an Fc domain, comprising a first Fc region and a second Fc region, each Fc region comprising a CH2 domain and a CH3 domain; said Fc domain further comprising at least one modification to promote heterodimerization; wherein the heavy chain of the first antigen binding arm and the heavy chain of the first T cell binding arm are attached to the Fc domain, and the heavy chain of the second antigen binding arm is attached to the heavy chain of the first T cell binding arm.

39. A tetraval ent T cell engaging molecule comprising the trivalent T cell engaging molecule according to claim 38, further comprising (d) a second T cell binding arm that binds to cluster of differentiation 8 (CD8) and comprises a heavy chain comprising a variable heavy domain (VHH) comprising a VH-CDR1 set forth in SEQ ID NO: 84; a VH-CDR2 set forth in SEQ ID NO: 85; and a VH-CDR3 set forth in SEQ ID NO: 86.

40. The tetravalent T cell engaging molecule according to claim 39, wherein the heavy chain of the second T cell binding arm is attached to the heavy chain of the first antigen binding arm.

41. The tetravalent T cell engaging molecule according to claim 39 or 40, wherein the heavy chain of the second antigen binding arm is attached to the heavy chain of the first T cell binding arm through a linker.

42. The tetravalent T cell engaging molecule according to any one of claims 39 or 41, wherein the heavy chain of the second T cell binding arm is attached to the heavy chain of the first antigen binding arm through a linker.

43. The trivalent or tetraval ent T cell engaging molecule according to claim 41 or 42, wherein the linker comprises the amino acid sequence of SEQ ID NO: 89.

44. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 41 to 43, wherein the linker comprises from 1 to about 10 copies of SEQ ID NO: 89.

45. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 41 to 44, wherein the linker comprises 2 copies of SEQ ID NO: 89.

46. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 45, wherein one of the two CH3 domains comprises a knob mutation, and the other of the two CH3 domains comprises a hole mutation.

47. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 46, wherein the CHI domain and the light chain constant domain of one or more of each of the (a) first antigen binding arm or second antigen binding arm, and (b) the first T cell binding arm, comprises a charge pair substitution comprising a first charged amino acid substitution in the CHI domain and a second charged amino acid substitution in the light chain constant domain, wherein the first charged amino acid substitution and the second charged amino acid substitution have an opposite charge.

48. The trivalent or tetravalent T cell engaging molecule according to claim 47, wherein the light chain constant domain of one or more of each of (a) the first antigen binding arm or the second antigen binding arm, and (b) the first T cell binding arm is a lambda light chain constant domain (CLX) and wherein the charge pair is a lambda charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and anegatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine, wherein the numbering is according to the EU index and wherein the lambda charge pair is located at one or more of the following positions:(i) position 117 in the CLX. and position 141 in the CHI domain;(ii) position 117 in the CLX and position 185 in the CHI domain;(iii) position 119 in the CLX and position 128 in the CHI domain;(iv) position 134 in the CLX and position 128 in the CHI domain;(v) position 134 in the CLX and position 145 in the CHI domain;(vi) position 134 in the CLX and position 183 in the CHI domain;(vii) position 136 in the CLX and position 185 in the CHI domain;(viii) position 178 in the CLX and position 173 in the CHI domain; and(ix) position 117 in the CLX and position 187 in the CHI domain.

49. The trivalent or tetravalent T cell engaging molecule according to claim 48, wherein (i) the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 141 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 141 is threonine;(ii) the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 185 is threonine;(iii) the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 119 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 119 is lysine and the charged amino acid at position 128 is threonine;(iv) the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 128 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 128 is threonine;(v) the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 145 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 145 is threonine;(vi) the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is serine; the charged amino acid at position 134 is arginine and the charged amino acid at position 183 is threonine; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is aspartic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is glutamic acid; the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is serine; or the charged amino acid at position 134 is lysine and the charged amino acid at position 183 is threonine;(vii) the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is serine; the charged amino acid at position 136 is arginine and the charged amino acid at position 185 is threonine; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is aspartic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is glutamic acid; the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is serine; or the charged amino acid at position 136 is lysine and the charged amino acid at position 185 is threonine;(viii) the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is serine; the charged amino acid at position 178 is arginine and the charged amino acid at position 173 is threonine; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is aspartic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is glutamic acid; the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is serine; or the charged amino acid at position 178 is lysine and the charged amino acid at position 173 is threonine; and / or(ix) the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is serine; the charged amino acid at position 117 is arginine and the charged amino acid at position 187 is threonine; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is aspartic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is glutamic acid; the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is serine; or the charged amino acid at position 117 is lysine and the charged amino acid at position 187 is threonine.

50. The trivalent or tetravalent T cell engaging molecule according to any one of claims 47 to 49, wherein the light chain constant domain of one or more of each of (a) the first antigen binding arm or the second antigen binding arm, and (b) the first T cell binding arm are kappa light chain constant domains (CLK) and wherein the charge pair is a kappa charge pair comprising a positively charged amino acid residue selected from arginine, lysine or histidine, and a negatively charged amino acid residue selected from aspartic acid, glutamic acid, serine or threonine, wherein the numbering is according to the EU index and wherein the kappa charge pair is located at position 133 in the CLK and position 183 in the CHI.

51. The trivalent or tetraval ent T cell engaging molecule according to claim 50, wherein the charged amino acid at position 133 is glutamic acid and the charged amino acid at position 183 is lysine; or the charged amino acid at position 133 is lysine and the charge amino acid at position 183 is glutamic acid.

52. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 51 wherein the light chain constant domain of one of (a), (b), and (d) is a CLX and wherein the charge pair is a lambda charge pair and the light chain constant domain of a second and a third of (a), (b), and (d) is a CLX or a CLK and wherein the charge pair is a lambda or a kappa charge pair and the second of (a), (b), and (d) comprises a charged amino acid in the CHI domain of a same charge as a charged amino acid in the CHI domain of the third of (a), (b), and (d).

53. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 51, wherein the light chain constant domain of one of (a), (b), and (d) is a CLX and wherein the charge pair is a lambda charge pair and the light chain constant domain of a second and a third of (a), (b), and (d) is a CLK and wherein the charge pair is a kappa charge pair and the second of (a), (b), and (d) comprises a charged amino acid in the CHI domain of a same charge as a charged amino acid in the CHI domain of the third of (a), (b), and (d).

54. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 53, wherein the CHI domain of (a) and / or (b) of the trivalent T cell engaging molecule or the CHI domain of (a), (b), and / or (d) of the tetravalent T cell engaging molecule is capable of forming a disulfide link to the light chain constant domain of (a) and / or (b) of the trivalent T cell engaging molecule or the light chain of (a), (b), and / or (d) of the tetravalent T cell engaging molecule through an engineered disulfide link.

55. The trivalent T cell engaging molecule according to any one of claims 38 to 54, wherein the CHI domain of (b) is capable of forming a disulfide link to the light chain constant domain through an engineered disulfide link and the CHI domain of (a) is linked to the light chain constant domain through a native disulfide link.

56. The tetravalent T cell engaging molecule according to any one of claims 38 to 54, wherein the CHI domain of (b) and (d) are capable of forming a disulfide link to the light chain constant domain of (b) and (d) through an engineered disulfide link and the CHI domain of (a) is linked to the light chain constant domain of (a) through a native disulfide link.

57. The trivalent or tetravalent T cell engaging molecule according to any one of claims 38 to 56, wherein CHI domain of the first T cell binding arm comprises(i) a substitution of a native cysteine to a non-cysteine amino acid,(ii) a substitution of a native non-cysteine amino acid to a cysteine; and the light chain constant domain of the second T cell binding arm comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid,(ii) a substitution of a native non-cysteine amino acid to a cysteine; wherein the substituted cysteine of the CHI domain of the first T cell binding arm and the substituted cysteine of the light chain constant domain of the first T cell binding arm can form a disulfide bond.

58. The trivalent or tetravalent T cell engaging molecule according to claim 57, wherein the CHI domain comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 220,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 126; and the light chain constant domain comprises:(i) a substitution of a native cysteine to a non-cysteine amino acid at position 212,(ii) a substitution of a native non-cysteine amino acid to a cysteine at position 122,wherein the cysteine at position 126 of the CHI domain and the cysteine at position 122 of the light chain constant domain can form a disulfide bond; wherein the numbering is according to the EU index.

59. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 58, wherein the light chains of the first and second antigen binding arms comprise a native cysteine and the CHI domain of the first and second antigen binding arms comprise a native cysteine, wherein the native cysteine of the CHI domain of the first antigen binding arm and the native cysteine of the light chain constant domain of the first antigen binding arm can form a disulfide bond and the native cysteine of the CHI of the second antigen binding arm and the native cysteine of the light chain constant domain of the second antigen binding arm can form a disulfide bond.

60. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 59, wherein the VH of the first and / or second antigen binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 7, 15, 23, 95, 97, 99, 106, 114, 133, 141, and 149.

61. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 59 wherein the heavy chain of the first and / or second antigen binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NO: 67 and 93.

62. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 60, wherein the VL of the first and / or second antigen binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 8, 16, 24, 107, 115, 134, 142, and 150.

63. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 61, wherein the light chain constant domain of the first and / or second antigen binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 63.

64. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 62, wherein the VL of the first T cell binding arm comprises a VL-CDR1 set forth in SEQ ID NO: 27 or 31; a VL-CDR2 set forth in SEQ ID NO: 28 or 32; a VL-CDR3 set forth in SEQ ID NO: 29 or 33; and the VH of the first T cell binding arm comprises a VH-CDR1 set forth in SEQ ID NO: 36, 40, or 44; a VH-CDR2 set forth in SEQ ID NO: 37, 41 or 45; and a VH- CDR3 set forth in SEQ ID NO: 38, 42, or 46.

65. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 63, wherein the VL of the first T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 30 or 34.

66. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 64, wherein the VH of the first T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NOs: 39, 43, and 47.

67. The tetravalent T cell engaging molecule according to any one of claims 38 to 65, wherein the VH of the second T cell binding arm comprises a VH-CDR1 set forth in SEQ ID NO: 84; a VH-CDR2 set forth in SEQ ID NO: 85; and a VH-CDR3 set forth in SEQ ID NO: 86.

68. The tetravalent T cell engaging molecule according to any one of claims 38 to 66, wherein the VH of the second T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, atleast about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 56 or 83.

69. A tetravalent T cell engaging molecule comprising the trivalent T cell engaging molecule according to claim 38, further comprising (d) a second T cell binding arm.

70. The tetravalent T cell engaging molecule according to claim 69, wherein the second T cell binding arm comprises a VL comprising a VL-CDR1 set forth in SEQ ID NO: 51; a VL- CDR2 set forth in SEQ ID NO: 52; and a VL-CDR3 set forth in SEQ ID NO: 53, and a VH comprising a VH-CDR1 set forth in SEQ ID NO: 48; a VH-CDR2 set forth in SEQ ID NO: 49; and a VH-CDR3 set forth in SEQ ID NO: 50.

71. The tetravalent T cell engaging molecule according to claim 70, wherein the VL of the second T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 54, and wherein the VH of the second T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 56.

72. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 70, wherein the first and the second antigen binding arm bind an epitope on an extracellular loop of STEAP2.

73. The trivalent or tetraval ent T cell engaging molecule according to any one of claims 38 to 71, wherein the heavy chain comprising the heavy chain constant region of the second antigen binding arm and the first T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence set forth in SEQ ID NO: 81.

74. The tetravalent T cell engaging molecule according to any one of claims 38 to 67, 71 and 72, wherein the heavy chain comprising the heavy chain constant region of the first antigen binding arm and the second T cell binding arm comprises an amino acid sequence having at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% sequence identity to an amino acid sequence selected from SEQ ID NO: 87.

75. The trivalent T cell engaging molecule according to any one of claims 38 to 65, 71, and 72, wherein the trivalent T cell engaging molecule comprises SEQ ID NOs: 25, 35, 81, 25, and 93.

76. The tetravalent T cell engaging molecule according to any one of claims 39 to 67, 71, and 73, wherein the tetravalent T cell engaging molecule comprises SEQ ID NOs: 25, 35, 81, 25, and 87, or wherein the tetravalent T cell engaging molecule comprises SEQ ID NOs: 151, 152, 153, 154, and 152.

77. One or more nucleic acid(s) encoding the T cell engaging molecule of any one of claims 1- 76.

78. A vector comprising the nucleic acid(s) of claim 77.

79. An isolated host cell comprising the nucleic acid(s) of claim 77, or the vector of claim 78.

80. A pharmaceutical composition comprising the T cell engaging molecule according to any one of claims 1 to 76 and a pharmaceutically acceptable carrier.

81. A method of treating a disease in a patient in need thereof, the method comprising administering to the patient an effective amount of the T cell engaging molecule according to any one of claims 1 to 76, or the pharmaceutical composition according to claim 80.

82. The method of claim 81, wherein the disease is cancer or prostate cancer.

83. The T cell engaging molecule according to any one of claims 1 to 76, or pharmaceutical composition according to claim 80, for use as a medicament.

84. The T cell engaging molecule according to any one of claims 1 to 76, or pharmaceutical composition according to claim 80, for use in the treatment of cancer.

85. Use of the T cell engaging molecule according to any one of claims 1 to 76, or pharmaceutical composition according to claim 80, for the manufacture of a medicament for the treatment of cancer.

Images