SLITRK6 binder, its conjugates, and its method of use

Abstract

The present invention provides a SLITRK6 antibody, its antigen-binding portion, other binders and its SLITRK6 conjugate, as well as methods and uses of such antibody and conjugate for treating cancer and autoimmune diseases.

Description

Technology Field

[0001] Cross-reference

[0002] This patent application claims the benefit of U.S. provisional application No. 63 / 619,728 filed on January 10, 2024 and international application No. PCT / CN2024 / 086162 filed on April 4, 2024, the full text of each of which is incorporated herein by reference.

[0003] Technology field

[0004] The present disclosure generally relates to antibodies and antibody-drug conjugates, as well as methods of using antibodies and antibody-drug conjugates, in particular to methods related to such antibodies, antibody-drug conjugates, and SLITRK6-expressing diseases and disorders. Background Technology

[0005] The use of monoclonal antibodies (mAbs) in the form of antibody-drug conjugates (or ADCs) for the targeted delivery of cytotoxic agents to disease-associated cells, such as cancer cells and other cells, has received significant attention. Designing antibody-drug conjugates by attaching cytotoxic agents, immunomodulators, or other agents (collectively "drugs") to antibodies, typically via a linker, involves the consideration of various factors. These factors include the identity and location of chemical groups for drug attachment, the mechanism of drug release, the structural element(s) providing drug release (if present), and the structural modification of the released free drug (if present). If the drug is released into the extracellular environment, the released form of the drug must be able to reach its target. If the drug is to be released after internalization of the antibody-drug conjugate, the structural elements and mechanism of drug release must be consistent with the intracellular trafficking of the conjugate.

[0006] Another important factor in the design of antibody-drug conjugates is the amount of drug that can be delivered per targeting agent (i.e., the number of drugs attached to each targeting agent (e.g., antibody), referred to as the drug load or drug loading). Historically, it was assumed that higher drug loads were superior to lower drug loads (e.g., 8-loads versus 4-loads). The rationale was that higher-loaded conjugates would deliver more drugs (e.g., cytotoxic agents) to target cells. This rationale was supported by the observation that conjugates with higher drug loadings were more active against cell lines in vitro. However, subsequent studies revealed that this assumption was not confirmed in animal models. Conjugates with drug loads of 4 or 8 of a specific auristatin were observed to have similar activity in mouse models. For example, see the literature [Hamblett et al., Clinical Cancer Res. 10:7063-70 (2004)]. Hamblett et al. further reported that higher-loaded ADCs cleared more rapidly from circulation in animal models. This faster clearance suggested PK issues for higher-loaded strains compared to lower-loaded strains. See Hamblett et al. Additionally, higher-loaded conjugates had a lower maximum allowable dose (MTD) in mice, resulting in a narrower reported therapeutic index (ibid.). In contrast, ADCs with a drug loading of 2 at the engineered site within the monoclonal antibody have been reported to have equal or superior PK and therapeutic indices compared to certain 4-loaded ADCs. For example, see Junutula et al., Clinical Cancer Res. 16:4769 (2010). Therefore, the recent trend is to develop ADCs with low drug loadings.

[0007] Attractive targets for cancer therapy using ADCs are SLIT and NTRK-like protein 6 (SLITRK6). The SLITRK6 protein is involved in the strict control of developmental processes, such as neurite growth and coordination, cell differentiation, and hormone regulation. SLITRK6 has been found to be highly expressed in various cancers, such as BLCA, BRCA, HNSC, LUCA, and GBMLGG, while exhibiting limited expression in normal tissues. This difference in expression between cancer and normal tissues makes it a promising tumor-associated antigen (Mol Cell Neurosci 2003; 24:117-129. Gene 2003; 315:87-94. Uniprot). However, the pace of developing effective SLITRK6 antibodies and related conjugates has been slow, and clinical trials using SLITRK6 antibodies and SLITRK6 ADCs have achieved limited success to date.

[0008] Therefore, there is a need for SLITRK6 antibodies in general, and in particular for SLITRK6 ADCs that enable higher drug loadings while retaining other features of lower-loaded conjugates, such as favorable PK characteristics. Embodiments of the present invention address these and related needs.

[0009] The present invention provides a SLITRK6 conjugate, an antibody-drug conjugate (ADC), and a method of using said conjugate and ADC to treat diseases, e.g., cancer and autoimmune diseases, to a non-limiting extent.

[0010] In some embodiments, a binder is provided comprising a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 disposed in a heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 disposed in a light chain variable region framework region, and the VH and VL CDRs are each SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, and SEQ ID NO: 8; each SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, and SEQ ID NO: 16; Each has an amino acid sequence selected from the set of amino acid sequences presented in the group consisting of sequence identification number: 19, sequence identification number: 20, sequence identification number: 21, sequence identification number: 22, sequence identification number: 23 and sequence identification number: 24; each, sequence identification number: 27, sequence identification number: 28, sequence identification number: 29, sequence identification number: 30, sequence identification number: 31 and sequence identification number: 32; and each, sequence identification number: 35, sequence identification number: 36, sequence identification number: 37, sequence identification number: 38, sequence identification number: 39 and sequence identification number: 40.

[0011] In some embodiments, a binder (e.g., an antibody or its antigen-binding portion) comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided, wherein the VH and VL regions each have amino acid sequences presented in pairs of amino acid sequences selected from Sequence ID No. 1 and Sequence ID No. 2; Sequence ID No. 9 and Sequence ID No. 10; Sequence ID No. 17 and Sequence ID No. 18; Sequence ID No. 25 and Sequence ID No. 26; and Sequence ID No. 33 and Sequence ID No. 34.

[0012] In some embodiments, the binder (e.g., antibody or its antigen-binding portion) comprises a heavy chain constant region comprising the amino acid sequence of SEQ ID NO: 49, 51, or 52. In some embodiments, the binder (e.g., antibody or its antigen-binding portion) comprises a light chain constant region comprising the amino acid sequence of SEQ ID NO: 50. In some embodiments, the binder (e.g., antibody or its antigen-binding portion) comprises a heavy chain constant region comprising the amino acid sequence of SEQ ID NO: 49, 51, or 52 and a light chain constant region comprising the amino acid sequence of SEQ ID NO: 50.

[0013] In some embodiments, a binder (e.g., an antibody or its antigen-binding portion) comprising a heavy chain and a light chain comprising the amino acid sequences presented in SEQ ID NOs: 53 and 55, respectively, is provided. In some embodiments, a binder (e.g., an antibody or its antigen-binding portion) comprising a heavy chain and a light chain comprising the amino acid sequences presented in SEQ ID NOs: 54 and 55, respectively, is provided.

[0014] In some embodiments, a pharmaceutical composition comprising a binder of the present disclosure and a pharmaceutically acceptable carrier is provided herein.

[0015] In some embodiments, a nucleic acid encoding a binder of the present disclosure is provided herein.

[0016] In some embodiments, a vector comprising the nucleic acid of the present disclosure is provided herein.

[0017] In some embodiments, cell lines comprising the binder, vector, or nucleic acid of the present disclosure are provided herein.

[0018] In some embodiments, a conjugate comprising a binder, at least one linker attached to the binder; and at least one drug unit is provided herein, wherein each drug unit is attached to the linker, wherein the linker optionally comprises at least one polar group.

[0019] In some embodiments, for a conjugate of the present disclosure, the linker is derived from a linker compound or its stereoisomer or salt, and the linker compound comprises a linker unit; a stretcher group connected to the linker unit; an optional amino acid unit; and at least one polar group; wherein the stretcher group has an attachment site for a binder and an attachment site for an amino acid unit (if present) or a linker subunit; the amino acid unit (if present) has an attachment site for a stretcher group and an attachment site for a linker unit; and the linker unit has an attachment site for an amino acid unit (if present) or a stretcher group and at least one drug unit.

[0020] In some embodiments, in the case of the conjugate of the present disclosure, the linker compound is

[0021] (a) a linker unit having 1 to 4 attachment sites for a drug unit;

[0022] (b) an amino acid unit having 1 to 12 amino acid subunits; and

[0023] (c) comprising at least one polar group attached to an amino acid unit, wherein the polar group comprises a polymer unit, optionally a sugar unit, and optionally a carboxyl unit, wherein the polymer unit is of the following chemical formula:

[0024] ~R 0 -(R 3 -R 1 -[O-CH2-CH2] n0 -R 6 -([O-CH2-CH2] n0 -R 2 -R 3 -(NR 4 R 5 ) n1 ) n2 ) n3

[0025] (Ia)

[0026] or including its stereoisomer or salt, where:

[0027] R 0 is a functional group for attachment to the subunit of an amino acid unit;

[0028] Each R 1 and R 2 is independently bonded or C1-C6 alkylene;

[0029] Each R 3 They combine independently, C1-C 12 Alkylene, -C(O)-, -NR a -C1-C 12 Alkylene, -C1-C 12 Alkylene-NR a -, -C(O)-C1-C 12 Alkylene, -C1-C 12 Alkylene-C(O)-, -C1-C 12 Alkylene-NR a -C(O)-, -C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -NR a -C1-C 12 Alkylene-C(O)-, -C(O)-C1-C 12 Alkylene-NR a -, -NR a -C(O)-NR a -, -NR a -C(O)-, -NR a -C(O)-C1-C 12 Alkylene, -C(O)-NR a -C1-C 12 Alkylene, -heteroarylene, heteroaryl-C1-C 12 Alkylene, heteroaryl-C1-C 12 Alkylene-C(O)-, -NR a -C(O)-C1-C 12 Alkylene-C(O)-, -C(O)-NR a -C1-C 12 Alkylene-(CH(OH)) 1-8 -C1-C 12 Alkylene-, -O-CH2-CH2, -OC(O)-NRa -C1-C 12 Alkylene, -O-CH2-CH(OH)-C(O)-, -O-CH2-CH(OH)-C(O)-NR a -C1-C 12 Alkylene-, -CH(OH)-, -CH(OH)-C1-C 12 Alkylene-, C1-C 12 Alkylene-CH(OH)-, -CH(OH)-C(O)-, -CH(OH)-C(O)-NR a -C1-C 12 Alkylene-, -CH(OH)-C1-C 12 Alkylene-NR a -C(O)-C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -NR a -C(O)-C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -CH(OH)-NR a -C1-C 12 Alkylene-, -[C(O)-(CH2) 1-8 -NR a ] 1-8 -, triazolyl, -C1-C 12 Alkylene-triazolyl-, -N(polyhydroxyl group- and -C(O)NR 7 R 8 Selected from, where R 7 and R 8 One of them is H or C1-C 12 It is an alkylene and the other is C1-C 12 It is an alkylene, and each R a is independently H, C 1-6 Selected from alkyl, wherein any of the alkylene groups can be substituted with -SO3H;

[0030] Each R 4 and R 5is independently H, a polyhydroxyl group, a carboxyl-containing moiety, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0031] Each R 6 It is selected from the following:

[0032] (i) , here:

[0033] Each n 3 and n 4 is independently 0-1, and

[0034] Each R b is independently H or C 1-6 It is alkyl, and

[0035] Each R 9 is independently H, acetyl, -P(=O)(OH)2, or -(CH2) v -OS(=O)2(OH) and,

[0036] Each p is independently 0-6, and

[0037] m is 1-4, and

[0038] Each v is independently 1-6, and

[0039] n 2 is 1;

[0040] (ii) , here:

[0041] Each R a is independently H or C 1-6 It is alkyl, and

[0042] Each R b is independently H or C 1-6 It is alkyl, and

[0043] n6 is 1-10, and

[0044] Each p is independently 0-6, and

[0045] n 2 is 1;

[0046] (iii) , here:

[0047] Each R a is independently H or C 1-6 It is alkyl, and

[0048] Each R b is independently H or C 1-6 It is alkyl, and

[0049] Each R 9 is independently H, acetyl, -P(=O)(OH)2, or -(CH2) v -OS(=O)2(OH) and,

[0050] Each p is independently 0-6, and

[0051] q is 1-8, and

[0052] Each v is independently 1-6, and

[0053] n 2 is 1;

[0054] (iv) , here:

[0055] Each R a is independently H or C 1-6 It is alkyl, and

[0056] Each R b is independently H or C 1-6 It is alkyl, and

[0057] Each p is independently 0-6, and

[0058] n 2 is 1;

[0059] (v) -R 10 -[O-CH2-CH2] 1-8 -R 10 -, here:

[0060] Each R b is independently H or C 1-6 It is alkyl, and

[0061] Each R 10 is independently And,

[0062] Each p is independently 1-6, and

[0063] Each R 9 is independently H, acetyl, -P(=O)(OH)2, or -(CH2) v -OS(=O)2(OH) and,

[0064] q is 1-8 and;

[0065] n 2 is 1;

[0066] (vi) -N-(R 1 -XR 2 -)2, here:

[0067] Each X is independently -NR a -C(O)- or -C(O)NR a - and,

[0068] n 2 is 2 and;

[0069] The wavy line (~) is R 0 Indicates the attachment site of the amino acid unit for;

[0070] Each n 0 is independently 2-26 and;

[0071] Each n 1 is independently 1-6 and;

[0072] n 3 It is 1-6.

[0073] In some embodiments, in the case of the conjugate of the present disclosure, the linker compound is

[0074] (a) a linker unit having 1 to 4 attachment sites for a drug unit;

[0075] (b) an amino acid unit having 1 to 12 amino acid subunits; and

[0076] (c) comprising at least one polar group attached to an amino acid unit, wherein the polar group comprises a polymer unit, optionally a sugar unit, and optionally a carboxyl unit, wherein the polymer unit is of the following chemical formula:

[0077] ~R 0 -(R 3 -R 1 -[O-CH2-CH2] n0 -R 2 -(NR 4 R 5 ) n1 ) n3

[0078] (Ia')

[0079] or including its stereoisomer or salt, where:

[0080] R 0 is a functional group for attachment to the subunit of an amino acid unit;

[0081] Each R 1 and R 2 is independently bonded or C1-C6 alkylene;

[0082] Each R 3 It independently -N(polyhydroxyl group)-, triazolyl, -C1-C 12 Alkylene-triazolyl-,

[0083] And;

[0084] Each R 4 and R 5 is independently H, a polyhydroxyl group, a carboxyl-containing moiety, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0085] Each R a is independently H or C 1-6 It is alkyl;

[0086] ( ) is R 0 R regarding 3 Indicates the attachment site of,

[0087] wavy line ( ) is R 1 R regarding 3 Indicates the attachment site of;

[0088] Each p is 1-6 and;

[0089] Each n 0 is independently 2-8 and;

[0090] Each n 1 is independently 1-6 and;

[0091] n 3 It is 1-6.

[0092] In some embodiments, in the case of the conjugate of the present disclosure, the linker compound is

[0093] (a) a linker unit having 1 to 4 attachment sites for a drug unit;

[0094] (b) an amino acid unit having 1 to 12 amino acid subunits; and

[0095] (c) comprising at least one polar group attached to an amino acid unit, wherein the polar group comprises a polymer unit, optionally a sugar unit, and optionally a carboxyl unit, wherein the polymer unit is of the following chemical formula:

[0096] ~R 0 -(R 1 -[O-CH2-CH2] n0 -R 2 -R 3 -(NR 4 R 5 ) n1 ) n3

[0097] (Ia)

[0098] or including its stereoisomer or salt, where:

[0099] (i) R 0 is a functional group for attachment to the subunit of an amino acid unit;

[0100] Each R 1 and R 2 is independently bonded or C1-C6 alkylene;

[0101] R 3 is -C(O)- and;

[0102] R 4 is H and;

[0103] R 5 is independently a polyhydroxyl group, a carboxyl-containing moiety, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and

[0104] The wavy line (~) is R 0 Indicates the attachment site of the amino acid unit for;

[0105] n 0 is independently 2-26 and;

[0106] n 1 is 1-6 and;

[0107] n 3 is 1-6 or;

[0108] (ii) R 0 is -C(O)- and;

[0109] R 1 , R 2 and R 3 Each is a combination;

[0110] R 4 and R 5is each independently H, a polyhydroxyl group, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0111] The wavy line (~) is R 0 Indicates the attachment site of the amino acid unit for;

[0112] n 0 It is 6 and;

[0113] n 1 is 1-6 and;

[0114] n 3 is 1 or;

[0115] (iii) R 0 is a functional group for attachment to the subunit of an amino acid unit;

[0116] R 1 and R 2 Each is independently bonded to a C1-C6 alkylene;

[0117] R 3 -NR a -C(O)-C1-C 12 Alkylene-C(O)-, where the alkylene is substituted with -SO3H;

[0118] R a is H or C 1-6 It is alkyl;

[0119] R 4 and R 5is each independently H, a carboxyl-containing moiety, a polyhydroxyl group, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0120] The wavy line (~) is R 0 Indicates the attachment site of the amino acid unit for;

[0121] Each n 0 is independently 1-26 and;

[0122] n 1 is 1-6 and;

[0123] n 3 is 1-6 or; or

[0124] (iv) R 0 silver And;

[0125] Each R 1 is independently bonded or C1-C6 alkylene;

[0126] R 2 and R 3 Each is a combination;

[0127] R 4 and R 5 is each independently H, a polyhydroxyl group, a carboxyl-containing moiety, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0128] Each Ra is independently H or C 1-6 It is alkyl;

[0129] wavy line ( ) is R for the remainder of the polymer unit 0 Indicates the attachment site of;

[0130] The wavy line (~*) is R 0 Indicates the attachment site of the amino acid unit for;

[0131] n 0 is 1-8 and;

[0132] n 1 is 1-6 and;

[0133] n 3 It is 2.

[0134] In some embodiments, for the conjugate of the present disclosure, the linker compound comprises the following:

[0135] (a) A linker unit having 1 to 4 attachment sites to a drug unit, said linker unit having a moiety of the following chemical formula:

[0136] ,

[0137] or includes its stereoisomer or salt, where:

[0138] α- represents a direct or indirect attachment site to an amino acid unit;

[0139] δ- indicates an attachment site for at least one of the drug units or for a linker attached to at least one of the drug units;

[0140] R a is H or C 1-6 alkyl;

[0141] (b) an amino acid unit having 1 to 12 amino acid subunits; and

[0142] (c) at least one polar group attached to an amino acid unit, wherein the polar group comprises a polymer unit, optionally a sugar unit, and optionally a carboxyl unit.

[0143] In some embodiments, in the case of the conjugate of the present disclosure, the linker compound is

[0144] (a) a linker unit having 1 to 4 attachment sites for a drug unit;

[0145] (b) an amino acid unit having 1 to 12 amino acid subunits; and

[0146] (c) comprising at least one polar group attached to an amino acid unit, wherein the polar group comprises a polymer unit, optionally a sugar unit, and optionally a carboxyl unit, wherein the polymer unit comprises the following:

[0147] (i) Chemical formula or an optionally substituted polyamide comprising its stereoisomer, wherein each R a is independently H or C 1-6 It is alkyl, and each R b is independently H or C 1-6 It is alkyl, and n 0 is independently 2-26;

[0148] (ii) Chemical formula or a substituted polyether comprising its stereoisomer, wherein each R b is independently H or C 1-6 It is alkyl, and n 0 is independently 2-26; or

[0149] (iii) His combination.

[0150] In some embodiments, in the case of the conjugate of the present disclosure, the linker compound is

[0151] (a) A linker unit having 1 to 4 attachment sites to a drug unit and having one of the following structures (i) or (ii):

[0152] ;

[0153] (b) at least one polar group comprising each polymer unit, and

[0154] (c) comprising a stretcher group having an attachment site to a binder;

[0155] Here:

[0156] α- is an attachment site for an enzyme-cleavable group;

[0157] β- is an attachment site for at least one polar group;

[0158] δ- is H, an attachment site for at least one of the drug units or an attachment site for a linker attached to at least one of the drug units;

[0159] The polymer unit comprises a polyamide, a polyether, or a combination thereof, wherein the polyether comprises a hydroxyl group, a polyhydroxyl group, a sugar group, a carboxyl group, or a combination thereof;

[0160] Each R a is independently H or C1-C6 alkyl;

[0161] Each R b is independently an attachment site for at least one of a halo, C1-6 alkyl, or drug unit, or an attachment site for at least one of a polar group;

[0162] x is 0, 1, 2, 3, or 4;

[0163] y is 0, 1, 2, or 3, and;

[0164] R c is a bond, -C(O)-, -S(O)-, -SO2-, C1-6alkylene, C 1-6 It is alkynylene, triazolyl, or a combination thereof;

[0165] Y is bonded, -O-, -S-, -N(R a )-, -C(O)-, -S(O)-, -SO2-C1-C6alkylene, C1-C6alkenylene, C1-C6alkynylene, triazolyl or a combination thereof.

[0166] In some embodiments, a pharmaceutical composition comprising a conjugate of the present disclosure and a pharmaceutically acceptable carrier is provided herein.

[0167] In some embodiments, a method for treating SLITRK6+ cancer is provided herein, comprising administering a therapeutically effective amount of a binder, pharmaceutical composition, conjugate, or pharmaceutical composition of the present disclosure to a subject requiring treatment for SLITRK6+ cancer.

[0168] In some embodiments, the use of a conjugate or pharmaceutical composition of the present disclosure for treating SLITRK6+ cancer in a subject is provided herein.

[0169] Additional features will be presented in part in the description below, will become apparent to a person skilled in the art upon review of the following and the accompanying drawings, or may be learned through the manufacture or operation of the embodiments. Features of the present disclosure may be realized and achieved by the practice or use of various aspects of the methodologies, means, and combinations presented in the detailed embodiments discussed below. Brief explanation of the drawing

[0170] The present disclosure is further described in terms of exemplary embodiments. These exemplary embodiments are described in detail with reference to the drawings. It should be noted that the drawings are not to scale. These embodiments are non-limiting exemplary embodiments, wherein equivalent reference numerals denote similar structures across various sides of the drawings, where: Figure 1 is a graph illustrating an epitope binning method; Figure 2a is a graph illustrating the ELISA binding results of antibodies phA290, phA108, hu1H2-03, hu1H2-13, hu14G1-03 and sirtratumab against human SLITRK6; Figure 2b is a graph illustrating the ELISA binding results of antibodies phA290, phA108, hu1H2-03, hu1H2-13, hu14G1-03 and sirtratumab against synomolgus monkey SLITRK6; Figure 3 is a graph illustrating the copy number of SLITRK6 on different SLITRK6-expressing cell lines; Figure 4a is a graph illustrating the binding activity of an antibody against 293F-huSLITRK6-C9 cells; Figure 4b is a graph illustrating the binding activity of antibodies against 293F cells (negative cells); Fig. 5a is a graph illustrating the binding activity of antibodies against SLITRK6-expressing tumor cell lines SW780, RT4, RT112 / 84, CHP-212, and SCC-4; Figure 5b is a graph illustrating the binding activity of an antibody against the SLITRK6-expressing tumor cell line SW780; Figure 5c is a graph illustrating the binding activity of an antibody against the SLITRK6-expressing tumor cell line RT4; Fig. 5d is a graph illustrating the binding activity of the antibody against the SLITRK6-expressing tumor cell line RT112 / 84; Figure 5e is a graph illustrating the binding activity of an antibody against the SLITRK6-expressing tumor cell line CHP-212; Fig. 6a is a graph illustrating the binding activity of antibodies (phA290, phA108, hu1H2-03, hu1H2-13, hu14G1-03, and sirtratumab) and ADCs (phA290-LD038 (8), phA108-LD038 (8), hu1H2-03-LD038 (8), hu1H2-13-LD038 (8), hu14G1-03-LD038 (8), and sirtratumab-LD038 (8)) against SLITRK6-expressing cell line SW780; Fig. 6b is a graph illustrating the binding activity of antibodies (phA290, phA108, hu1H2-03, hu1H2-13, hu14G1-03, and sirtratumab) and ADCs (phA290-LD038 (8), phA108-LD038 (8), hu1H2-03-LD038 (8), hu1H2-13-LD038 (8), hu14G1-03-LD038 (8), and sirtratumab-LD038 (8)) against SLITRK6-expressing cell line RT4; FIG. 6c is a graph illustrating the binding activity of antibodies (phA290, phA108, hu1H2-03, hu1H2-13, hu14G1-03, and sirtratumab) and ADCs (phA290-LD038 (8), phA108-LD038 (8), hu1H2-03-LD038 (8), hu1H2-13-LD038 (8), hu14G1-03-LD038 (8), and sirtratumab-LD038 (8)) against the SLITRK6-expressing cell line 293F-huSLITRK6-C9; FIG. 6d is a graph illustrating the binding activity of antibodies (phA290, phA108, hu1H2-03, hu1H2-13, hu14G1-03, and sirtratumab) and ADCs (phA290-LD038 (8), phA108-LD038 (8), hu1H2-03-LD038 (8), hu1H2-13-LD038 (8), hu14G1-03-LD038 (8), and sirtratumab-LD038 (8)) against SLITRK6-expressing cell line CHP-212; FIG. 7a is a graph illustrating the internalization rates of antibodies (phA290, phA108, and sirtratumab) and ADCs (phA290-LD038 (8), phA108-LD038 (8), and sirtratumab-LD038 (8)) in 293F-SLITRK6-C9 cells; FIG. 7b is a graph illustrating the internalization rates of antibodies (hu1H2-03, hu1H2-13, and hu14G1-03) and ADCs (hu1H2-03-LD038 (8), hu1H2-13-LD038 (8) and hu14G1-03-LD038 (8)) in 293F-SLITRK6-C9 cells; FIG. 7c is a graph illustrating the internalization rates of antibodies (hu1H2-03, hu1H2-13, and hu14G1-03) and ADCs (hu1H2-03-LD038 (8), hu1H2-13-LD038 (8) and hu14G1-03-LD038 (8)) in RT4 cells; FIG. 7d is a graph illustrating the internalization rates of antibodies (hu1H2-03, hu1H2-13, and hu14G1-03) and ADCs (hu1H2-03-LD038 (8), hu1H2-13-LD038 (8) and hu14G1-03-LD038 (8)) in RT4 cells; Fig. 8a is a graph illustrating the cytotoxicity of an ADC containing the linker-drug LD038 against 293F-SLITRK6-C9 cells; Fig. 8b is a graph illustrating the cytotoxicity of an ADC with linker-drug LD038 against 293F cells (negative cells); Fig. 8c is a graph illustrating the cytotoxicity of an ADC containing the linker-drug LD038 against RT4 cells; Fig. 8d is a graph illustrating the cytotoxicity of an ADC containing the linker-drug LD038 against CHP-212 cells; FIG. 9a is a graph illustrating the in vivo efficacy of a single dose of SLITRK6-targeted ADC phA290-LALA-LD038 (8), AGS15E, b12-WT-LD038 against CHP-212; FIG. 9b is a graph illustrating the in vivo efficacy of single doses of SLITRK6-targeted ADCs phA108-WT-LD038 (8), hu14G1-03-WT-LD038 (8), hu1H2-03-WT-LD038 (8) and AGS15E against CHP-212; FIG. 9c is a graph illustrating the in vivo efficacy of multiple doses of SLITRK6-targeted ADCs phA108-WT-LD038 (8), hu14G1-03-WT-LD038 (8), hu1H2-03-WT-LD038 (8) and AGS15E against CHP-212; FIG. 9d is a graph illustrating the in vivo efficacy of single and multiple doses of SLITRK6-targeted ADCs phA108-WT-LD038 (8), hu14G1-03-WT-LD038 (8), hu1H2-03-WT-LD038 (8) and AGS15E against SW780; Figure 9e is a graph illustrating the in vivo efficacy of multiple doses of SLITRK6-targeted ADCs phA290-WT-LD038 (8), phA108-WT-LD038 (8), hu14G1-03-WT-LD038 (8), hu1H2-03-WT-LD038 (8), hu1H2-13-WT-LD038 (8), AGS15E and b12-WT-LD038 (8) against RT4. Fig. 10a is a graph illustrating the binding activity of antibodies (hu1H2-03 and sirtratumab) against SLITRK6-expressing tumor cell lines RT4 and their respective ADCs (hu1H2-03-LD038 and AGS15E); Fig. 10b is a graph illustrating the binding activity of antibodies (hu1H2-03 and sirtratumab) and their respective ADCs (hu1H2-03-LD038 and AGS15E) against SW780 cells; Fig. 10c is a graph illustrating the binding activity of antibodies (hu1H2-03 and sirtratumab) against RT112 / 84 cells and their respective ADCs (hu1H2-03-LD038 and AGS15E); Fig. 10d is a graph illustrating the binding activity of antibodies (hu1H2-03 and sirtratumab) against CHP-212 cells and their respective ADCs (hu1H2-03-LD038 and AGS15E); Fig. 10e is a graph illustrating the binding activity of antibodies (hu1H2-03 and sirtratumab) against KYSE-30 cells and their respective ADCs (hu1H2-03-LD038 and AGS15E); Fig. 10f is a graph illustrating the binding activity of antibodies (hu1H2-03 and sirtratumab) and their respective ADCs (hu1H2-03-LD038 and AGS15E) against KYSE-410 cells; Fig. 10g is a graph illustrating the binding activity of antibodies (hu1H2-03 and sirtratumab) against 293F-huSLITRK6 cells and their respective ADCs (hu1H2-03-LD038 and AGS15E); Figure 10h is a graph illustrating the binding activity of antibodies (hu1H2-03 and sirtratumab) against negative cells and their respective ADCs (hu1H2-03-LD038 and AGS15E). Fig. 11a is a graph illustrating the plasma PK of hu1H2-03-LD038 (8) or hu1H2-03 in rats (n=3 / group); Fig. 11b is a graph illustrating the plasma PK of hu1H2-03-LD038 (8) in monkeys (n=2); FIG. 12 is a graph illustrating the hydrophobic interaction chromatographs of hu1H2-03-LD038 (8), hu1H2-03-LD343 (8), AGS15E, and its parent mAb (hu1H2-03, sirtratumab); Fig. 13a is a graph illustrating the binding activity of antibodies (hu1H2-03 and sirtratumab) and their respective ADCs (hu1H2-03-LD343 and AGS15E) against SW780 cells; Fig. 13b is a graph illustrating the binding activity of antibodies (hu1H2-03 and sirtratumab) against RT4 cells and their respective ADCs (hu1H2-03-LD343 and AGS15E); Fig. 14a is a graph illustrating the internalization rates of antibodies (hu1H2-03 and sirtratumab) and their respective ADCs (hu1H2-03-LD038 and AGS15E) in SW780 cells; Fig. 14b is a graph illustrating the internalization rates of antibodies (hu1H2-03 and sirtratumab) and their respective ADCs (hu1H2-03-LD038 and AGS15E) in RT4 cells; Fig. 14c is a graph illustrating the internalization rates of antibodies (hu1H2-03 and sirtratumab) and their respective ADCs (hu1H2-03-LD343 and AGS15E) in RT4 cells; Fig. 15a is a graph illustrating the cytotoxicity of hu1H2-03-LD038 and AGS15E against 293F-SLITRK6 cells; Fig. 15b is a graph illustrating the cytotoxicity of hu1H2-03-LD038 and AGS15E against 293F cells; Fig. 15c is a graph illustrating the cytotoxicity of hu1H2-03-LD038 and AGS15E against SW780 cells; Fig. 15d is a graph illustrating the cytotoxicity of hu1H2-03-LD038 and AGS15E against RT4 cells; Figure 15e is a graph illustrating the cytotoxicity of hu1H2-03-LD038 and AGS15E against RT112 / 84 cells; Fig. 15f is a graph illustrating the cytotoxicity of hu1H2-03-LD038 and AGS15E against CHP-212 cells; Figure 15g is a graph illustrating the cytotoxicity of hu1H2-03-LD038 and AGS15E against KYSE-410 cells; Figure 15h is a graph illustrating the cytotoxicity of hu1H2-03-LD038 and AGS15E against KYSE-30 cells; Fig. 15i is a graph illustrating the cytotoxicity of hu1H2-03-LD343 and AGS15E against SW780 cells; Fig. 15j is a graph illustrating the cytotoxicity of hu1H2-03-LD343 and AGS15E against RT4 cells; Fig. 16a is a graph illustrating the in vivo efficacy of a single dose of the hu1H2-03-LD038 analog, hu1H2-03-LD038, and AGS15E on SW780 cells; Fig. 16b is a graph illustrating the in vivo efficacy of single doses of hu1H2-03-LALA-LD038 and AGS15E on RT4 cells; Fig. 16c is a graph illustrating the in vivo efficacy of single doses of hu1H2-03-WT-LD038 and AGS15E on CHP-212 cells; Fig. 16d is a graph illustrating the in vivo efficacy of single doses of hu1H2-03-LD038 and AGS15E on KYSE-410 cells; Figure 16e is a graph illustrating the in vivo efficacy of single doses of hu1H2-03-LD038 and AGS15E on KYSE-30 cells; Fig. 16f is a graph illustrating the in vivo efficacy of single doses of hu1H2-03-LD343 and AGS15E on SW780 cells; Fig. 16g is a graph illustrating the in vivo efficacy of single doses of hu1H2-03-LD343 and AGS15E on RT4 cells; Figure 17 is a graph illustrating the in vivo efficacy of single doses of hu1H2-03-LD038, hu1H2-03-LD343, and AGS15E against bladder cancer cells in a PDX model. Specific details for implementing the invention

[0171] The following description is provided to enable any person skilled in the art to manufacture and use the present disclosure, and is provided in relation to specific applications and requirements thereof. Various variations of the disclosed embodiments will be readily apparent to a person skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present disclosure. Accordingly, the present disclosure is not limited to the embodiments presented, but should be in accordance with the broadest scope consistent with the claims.

[0172] The terms used herein are merely for describing specific exemplary embodiments and are not intended to be limiting. The singular forms used herein may also be intended to include the plural forms unless the context otherwise clearly indicates. The terms “include,” “including,” “include,” and / or “included” will be further understood as specifying the presence of the mentioned features, integers, steps, operations, elements, and / or components when used herein, but not excluding the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0173] These and other features and characteristics of the present disclosure, as well as the functions of related elements of the working method and structure, the combination of parts, and the economics of manufacturing, may all become more apparent when considering the following description with reference to the accompanying drawings(s) which form part of this specification. However, it should be clearly understood that the drawings(s) are for illustrative and illustrative purposes only and are not intended to limit the scope of the present disclosure. The drawings are understood not to be in scale.

[0174] definition

[0175] For convenience, specific terms in the specification, embodiments, and claims are defined herein. Unless otherwise stated or implied by the context, the following terms and phrases have the meanings provided below. Definitions are provided to aid in describing specific embodiments and are not intended to limit the claimed invention, as the scope of the invention is limited only by the claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by a person skilled in the art to which the invention pertains.

[0176] Unless otherwise indicated, singular terms used herein are interpreted to mean "one," "at least one," or "one or more." Unless otherwise required by the context, singular terms used herein will include the plural, and plural terms will include the singular.

[0177] Unless the context clearly requires otherwise, throughout the description and claims, words such as “include,” “including,” etc., should be interpreted in an inclusive sense, as opposed to an exclusive or all-encompassing sense; that is, in the sense of “including but not limited thereto.”

[0178] The terms "degraded," "reduce," "reduced," "reduction," "reduce," and "inhibit" are all used herein to generally mean a reduction of a statistically significant amount compared to the reference.

[0179] The terms "increased," "increase," "promote," or "activate" are all used herein to generally mean an increase of a statistically significant amount compared to the reference.

[0180] As used herein, the terms “protein” and “polypeptide” are used interchangeably to refer to a series of amino acid residues connected to one another by peptide bonds between the alpha-amino and carboxyl groups of adjacent residues. The terms “protein” and “polypeptide” also refer to polymers of amino acids, including modified amino acids (e.g., phosphorylated, glycosylated, etc.) and amino acid analogs, regardless of their size or function. While “protein” and “polypeptide” are often used in relation to relatively large polypeptides, the term “peptide” is often used in relation to small polypeptides; however, the use of these terms overlaps in the relevant technical field. The terms “protein” and “polypeptide” are used interchangeably herein to refer to coded gene products and their fragments. Thus, exemplary polypeptides or proteins include gene products, naturally occurring proteins, homologs, orthologs, paralogs, fragments, and other equivalents, variants, fragments, and analogs thereof.

[0181] SLITRK6 (protein tyrosine kinase-like 7) is a member of the receptor protein tyrosine kinase family and is also known as colorectal carcinoma kinase 4 (CCK4). In humans, this protein is encoded by the SLITRK6 gene. SLITRK6 is overexpressed on the surface of many types of cancer, including but not limited to solid tumors. These solid tumors include, but are not limited to, breast cancer (BC), lung cancer (LC), esophageal cancer (EsC), gastric cancer (GC), bladder cancer (BLC), endometrial cancer (EC), ovarian cancer (OVC), and head and neck cancer (HNC), as well as hematological malignancies. Human SLITRK6 polypeptides include, but are not limited to, those having the amino acid sequence presented in UniProt identifier Q13308 and those having the amino acid sequence presented in Genbank, such as Genbank accession numbers NP_002812.2, NP_690619.1, NP_690620.1, NP_690621.1, NP_001257327.1, XP_011513067.1, XP_011513068.1, XP_047275113.1, XP_054212039.1, XP_054212040.1, and XP_054212041.1, which are incorporated herein by reference but are not limited thereto. Although it lacks detectable catalytic tyrosine kinase activity, SLITRK6 overexpression is closely associated with Wnt signaling and promotes cancer cell stem cell characteristics, survival, and tumor progression (e.g., literature [Atasaven et al., 2013; Cui et al., 2021; Gaertner, 2014; Chen et al., 2014; Jiang et al., 2020; Shin et al., 2013; Liu et al., 2017; Lin et al., 2012; Oezcelik et al., 2020; Xiang et al., 2022; Wang et al., 2014; Prebet et al., 2010; Jiang et al.[See , 2012; Damelin et al., 2017]). Although SLITRK6 expression in normal tissues is generally low, some levels of protein expression have been reported in the gastrointestinal tract, e.g., bladder, kidney, mammary gland, lung, ovary, uterus, and dendritic cells (Damelin et al., 2017). Therefore, SLITRK6 is a promising target for novel anticancer therapies.

[0182] As used herein, the term “epitope” refers to an amino acid typically bound by an immunoglobulin VH / VL pair, such as an antibody, its antigen-binding portion, and other binders described herein. An epitope may be formed on a polypeptide from adjacent amino acids or non-adjacent amino acids juxtaposed by tertiary folding of the protein. Epitopes formed from adjacent amino acids are typically retained upon exposure to denaturing solvents, whereas epitopes formed by tertiary folding are typically lost upon treatment with denaturing solvents. An epitope typically comprises at least three, more typically at least five, about nine, or about eight to ten amino acids in a unique spatial conformation. The epitope defines the minimum binding site for the antibody, its antigen-binding portion, and other binders, and thus represents the target of specificity for the antibody, its antigen-binding portion, or other immunoglobulin-based binders. In the case of a single-domain antibody, the epitope represents a unit of structure bound by a single variable domain.

[0183] As used herein, "specifically binds" means that the binder described herein (e.g., an antibody or its antigen-binding portion) binds to a target, e.g., human SLITRK6 10 -5 M (10,000 nM) or less, e.g., 10 -6 M, 10 -7 M, 10 -8 M, 10 -9 M, 10 -10 M, 10 -11 M, 10 -12It refers to the ability to bind to a target with a KD of M or less. Specific binding may be influenced, for example, by the affinity and binding strength of the antibody, antigen-binding portion, or other binder, and the concentration of the target polypeptide. A person skilled in the art may determine the appropriate conditions under which the antibody, antigen-binding portion, and other binder described herein selectively bind to SLITRK6 by using any suitable method, such as titrating the antibody or other binder in a suitable cell binding assay. A binder specifically bound to SLITRK6 is not replaced by a non-similar competitor. In certain embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder is referred to as specifically binding to SLITRK6 when it preferentially recognizes its target antigen, SLITRK6, in a complex mixture of proteins and / or macromolecules.

[0184] In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder as described herein is 10 to the SLITRK6 polypeptide -5 M (10,000 nM) or less, e.g., 10 -6 M, 10 -7 M, 10 -8 M, 10 -9 M, 10 -10 M, 10 -11 M, 10 -12 It specifically binds to M, or a dissociation constant (KD) less than that. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder as described herein binds to the SLITRK6 polypeptide by about 10 -5 M to 10 -6 It specifically binds to the dissociation constant (KD) of M. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder as described herein binds to the SLITRK6 polypeptide by about 10 -7 M to 10 -8It specifically binds to the dissociation constant (KD) of M. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder as described herein binds to the SLITRK6 polypeptide by about 10 -8 M to 10 -9 It specifically binds to the dissociation constant (KD) of M. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder as described herein binds to the SLITRK6 polypeptide by about 10 -9 M to 10 -10 It specifically binds to the dissociation constant (KD) of M. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder as described herein binds to the SLITRK6 polypeptide by about 10 -10 M to 10 -11 It specifically binds to the dissociation constant (KD) of M. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder as described herein binds to the SLITRK6 polypeptide by about 10 -11 M to 10 -12 It specifically binds to the dissociation constant (KD) of M. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder as described herein binds to the SLITRK6 polypeptide by about 10 -12 M to 10 -13 It specifically binds to the dissociation constant (KD) of M. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder as described herein binds to the SLITRK6 polypeptide 10 -9 It specifically binds with a dissociation constant (KD) less than M.

[0185] Unless otherwise indicated, the term "alkyl" as itself or as part of another term refers to a substituted or unsubstituted straight-chain or branched, saturated hydrocarbon having the indicated number of carbon atoms (e.g., "-C1-C5 alkyl", "-C1-C8 alkyl", or "-C1-C10" alkyl each refer to an alkyl group having 1 to 5, 1 to 8, or 1 to 10 carbon atoms, respectively). Examples include methyl (Me, -CH3), ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -CH(CH3)CH2CH3), 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 2-pentyl (-CH(CH3)CH2CH2CH3), 3-pentyl (--CH(CH2CH3)2), and 2-methyl-2-butyl (-C(CH3)2CH2CH3), 3-methyl-2-butyl (-CH(CH3)CH(CH3)2), 3-methyl-1-butyl (-CH2CH2CH(CH3)2), 2-methyl-1-butyl (-CH2CH(CH3)CH2CH3), 1-hexyl (-CH2CH2CH2CH2CH2CH3), 2-hexyl (-CH(CH3)CH2CH2CH2CH3), 3-hexyl (-CH(CH2CH3)(CH2CH2CH3)), 2-methyl-2-pentyl (-C(CH3)2CH2CH2CH3), 3-methyl-2-pentyl (-CH(CH3)CH(CH3)CH2CH3), 4-methyl-2-pentyl (-CH(CH3)CH2CH(CH3)2), 3-methyl-3-pentyl (-C(CH3)(CH2CH3)2), It includes 2-methyl-3-pentyl (-CH(CH2CH3)CH(CH3)2), 2,3-dimethyl-2-butyl (-C(CH3)2CH(CH3)2) and 3,3-dimethyl-2-butyl (-CH(CH3)C(CH3)3).

[0186] Unless otherwise indicated, “alkenyl” as itself or as part of another term refers to a C2-C8 substituted or unsubstituted straight-chain or branched hydrocarbon having at least one unsaturated site (i.e., a carbon-carbon, sp2 double bond). Examples include, but are not limited to, ethylene or vinyl (-CH=CH2), allyl (-CH2CH=CH2), cyclopentenyl (-C5H7) and 5-hexenyl (-CH2CH2CH2CH2CH=CH2).

[0187] Unless otherwise indicated, “alkynyl” as itself or as part of another term refers to a C2-C8 substituted or unsubstituted straight-chain or branched hydrocarbon having at least one unsaturated site (i.e., carbon-carbon, sp triple bond). Examples include, but are not limited to, acetylene and propargyl.

[0188] Unless otherwise indicated, “alkylene” refers to a saturated, branched, straight-chain, or hydrocarbon radical of 1 to 8 carbon atoms having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent alkane. Typical alkylene radicals include, but are not limited to, methylene (-CH2-), 1,2-ethyl (-CH2CH2-), 1,3-propyl (-CH2CH2CH2-), 1,4-butyl (-CH2CH2CH2CH2-), etc.

[0189] Unless otherwise indicated, “alkenylene” refers to an unsaturated, branched, or straight-chain hydrocarbon radical of 2 to 8 carbon atoms having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent alkene. Typical alkenylene radicals include, but are not limited to, 1,2-ethylene (-CH=CH-).

[0190] Unless otherwise indicated, “alkynylene” refers to an unsaturated, branched, straight-chain, or cyclic hydrocarbon radical of 2 to 8 carbon atoms having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent alkyne. Typical alkynylene radicals include, but are not limited to, acetylene, propargyl, and 4-pentynyl.

[0191] Unless otherwise indicated, the term “heteroalkyl,” as itself or in combination with another term, refers to a saturated, substituted or unsubstituted stable straight-chain or branched-chain hydrocarbon or a combination thereof having 1 to 10, preferably 1 to 3, heteroatoms selected from the group consisting of O, N, Si, and S, wherein the nitrogen and sulfur atoms may optionally be oxidized and the nitrogen heteroatom may optionally be quaternized. The heteroatom(s) O, N, and S may be located at any internal position of the heteroalkyl group (i.e., as part of the main chain) or at a position where the alkyl group is attached to the remainder of the molecule. The heteroatom Si may be located at any position of the heteroalkyl group, including a position where the alkyl group is attached to the remainder of the molecule. Examples of heteroalkyls include the following: -CH2CH2OCH3, -CH2CH2NHCH3, -CH2CH2N(CH3)CH3, -CH2SCH2CH3, CH2CH2S(O)CH3, -CH2CH2S(O)2CH3, and -Si(CH3)3. Up to two heteroatoms may be consecutive, for example, as in -CH2NHOCH3 and CH2OSi(CH3)3. In some embodiments, C1 to C4 heteroalkyls have 1 to 4 carbon atoms and 1 or 2 heteroatoms, and C1 to C3 heteroalkyls have 1 to 3 carbon atoms and 1 or 2 heteroatoms.

[0192] Unless otherwise indicated, the terms “heteroalkenyl” and “heteroalkynyl” as themselves or in combination with other terms refer to a substituted or unsubstituted stable straight-chain or branched-chain alkenyl or alkynyl having 1 to 10, preferably 1 to 3, heteroatoms selected from the group consisting of O, N, Si, and S, wherein the nitrogen and sulfur atoms may optionally be oxidized and the nitrogen heteroatom may optionally be quaternized. The heteroatom(s) O, N, and S may be located at any internal position of the heteroalkenyl or heteroalkynyl group (i.e., as part of the main chain) or at a position where the alkyl group is attached to the remainder of the molecule. The heteroatom Si may be located at any position of the heteroalkenyl or heteroalkynyl group, including a position where the alkyl group is attached to the remainder of the molecule.

[0193] Unless otherwise indicated, the term “heteroalkylene” as itself or as part of another substituent refers to a substituted or unsubstituted divalent group derived from a heteroalkyl (as discussed above), as exemplified by -CH2CH2SCH2CH2- and -CH2SCH2CH2NHCH2-. In some embodiments, C1 to C4 heteroalkylenes have 1 to 4 carbon atoms and 1 or 2 heteroatoms, and C1 to C3 heteroalkylenes have 1 to 3 carbon atoms and 1 or 2 heteroatoms. In the case of a heteroalkylene group, the heteroatom may also occupy either or both of the chain ends. Additionally, in the case of alkylene and heteroalkylene linkers, the orientation of the linker is not implied.

[0194] Unless otherwise indicated, the terms “heteroalkenylene” and “heteroalkynylene” as themselves or as part of another substituent refer to a substituted or unsubstituted divalent group derived from heteroalkenyl or heteroalkynyl (as discussed above). In some embodiments, C2 to C4 heteroalkenylene or heteroalkynylene has 1 to 4 carbon atoms. In the case of heteroalkenylene and heteroalkynylene groups, the heteroatom may also occupy either or both of the chain ends. Additionally, in the case of alkylene and heteroalkenylene and heteroalkynylene linkers, the orientation of the linker is not implied.

[0195] Unless otherwise indicated, “C3-C8 carbocycle” as itself or as part of another term refers to a substituted or unsubstituted 3-, 4-, 5-, 6-, 7-, or 8-membered monovalent, substituted or unsubstituted, saturated or unsaturated non-aromatic monocyclic or noncyclic carbocyclic ring derived by the removal of one hydrogen atom from a ring atom of the parent ring system. Representative -C3-C8 carbocycles include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclopentadienyl, cyclohexyl, cyclohexenyl, 1,3-cyclohexadienyl, 1,4-cyclohexadienyl, cycloheptyl, 1,3-cycloheptadienyl, 1,3,5-cycloheptatrienyl, cyclooctyl, and cyclooctadienyl.

[0196] Unless otherwise indicated, "C3-C8 carbocyclo" as itself or as part of another term refers to the above-defined substituted or unsubstituted C3-C8 carbocyclo group in which another of the hydrogen atoms of the carbocyclo group is replaced by a bond (i.e., divalent).

[0197] Unless otherwise indicated, “C3-C10 carbocycle” as itself or as part of another term refers to a substituted or unsubstituted 3-, 4-, 5-, 6-, 7-, 8-, 9- or 10-membered monovalent, substituted or unsubstituted, saturated or unsaturated non-aromatic monocyclic, noncyclic or tricyclic carbocyclic ring induced by the removal of one hydrogen atom from a ring atom of the parent ring system. Representative -C3-C10 carbocycles include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclopentadienyl, cyclohexyl, cyclohexenyl, 1,3-cyclohexadienyl, 1,4-cyclohexadienyl, cycloheptyl, 1,3-cycloheptadienyl, 1,3,5-cycloheptatrienyl, cyclooctyl, and cyclooctadienyl. The -C3-C10 carbocycle may further include fused cyclooctine carbocycles, such as fused cyclooctine compounds disclosed in International Publication No. WO2011 / 136645 (the disclosure thereof is incorporated herein by reference), such as BCN (bicyclo[6.1.0]nonine) and DBCO (dibenzocyclooctine).

[0198] Unless otherwise indicated, "C3-C8 heterocycle" as itself or as part of another term refers to a substituted or unsubstituted monovalent substituted or unsubstituted aromatic or non-aromatic monocyclic or noncyclic ring system having 3 to 8 carbon atoms (also referred to as ring atoms) and 1 to 4 heteroatom ring atoms independently selected from N, O, P, or S, induced by the removal of 1 hydrogen atom from the ring atoms of the parent ring system. One or more N, C, or S atoms in the heterocycle may be oxidized. The ring containing the heteroatoms may be aromatic or non-aromatic. Unless otherwise indicated, the heterocycle is attached to its pendant group at any heteroatom or carbon atom that forms a stable structure. Representative examples of C3-C8 heterocycles include, but are not limited to, pyrrolidinyl, azetidinyl, piperidinyl, morpholinyl, tetrahydrofuranil, tetrahydropyranil, benzofuranil, benzothiophene, indolyl, benzopyrazolyl, pyrrolyl, thiophenyl (thiophene), furanyl, thiazolyl, imidazolyl, pyrazolyl, pyrimidinyl, pyridinyl, pyrazinyl, pyridazolyl, isothiazolyl, and isoxazolyl. Unless otherwise indicated, the term "heterocarbocycle" is synonymous with the terms "heterocycle" or "heterocyclo" as described herein.

[0199] Unless otherwise indicated, "C3-C8 heterocyclo" as itself or as part of another term refers to the above-defined substituted or unsubstituted C3-C8 heterocyclo group in which one of the hydrogen atoms of the heterocyclo group is replaced by a bond (i.e., divalent).

[0200] Unless otherwise indicated, "aryl," as itself or as part of another term, refers to a 6- to 20-carbon (preferably 6- to 14-carbon) substituted or unsubstituted monovalent carbocyclic aromatic hydrocarbon radical derived by the removal of one hydrogen atom from a single carbon atom of a parent aromatic ring system. Some aryl groups are denoted as "Ar" in exemplary structures. Typical aryl groups include, but are not limited to, radicals derived from benzene, substituted benzene, naphthalene, anthracene, biphenyl, etc. An exemplary aryl group is a phenyl group.

[0201] Unless otherwise indicated, “arylene” as itself or as part of another term is an unsubstituted or substituted aryl group as defined above, in which one of the hydrogen atoms of the aryl group is replaced by a bond (i.e., divalent) and may be ortho, meta, or para oriented.

[0202] Unless otherwise indicated, “heteroaryl” and “heterocycle” refer to a ring system in which one or more ring atoms are heteroatoms, e.g., nitrogen, oxygen, and sulfur. A heterocycle radical comprises 1 to 20 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S. A heterocycle may be a monocycle having 3 to 7 rings (2 to 6 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S) or a bicycle having 7 to 10 rings (4 to 9 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S), e.g., a bicyclo[4,5], [5,5], [5,6], or [6,6] system.

[0203] Unless otherwise indicated, “heteroarylene” as itself or as part of another term is an unsubstituted or substituted heteroaryl group as defined above, in which one of the hydrogen atoms of the heteroaryl group is replaced by a bond (i.e., divalent).

[0204] Unless otherwise indicated, "carboxyl" refers to COOH or COO-M+, where M+ is a cation.

[0205] Unless otherwise indicated, "oxo" refers to (C=O).

[0206] Unless otherwise indicated, "substituted alkyl" and "substituted aryl" refer to alkyl and aryl groups, respectively, in which one or more hydrogen atoms are independently replaced by substituents. Typical substituents are -X and -R 10 , -O - , -OR 10 , -SR 10 , -S-, -NR 102 , -NR 103 , =NR 10 , -CX3, -CN, -OCN, -SCN, -N=C=O, -NCS, -NO, -NO2, =N2, -N3, -NR 10 C(=O)R 10 , -C(=O)R 10 , -C(=O)NR 102 , -SO3-, -SO3H, -S(=O)2R 10 , -OS(=O)2OR 10 , -S(=O)2NR 10 , -S(=O)R 10 , -OP(=O)(OR 10 )2, -P(=O)(OR 10 )2, -PO-3, -PO3H2, -AsO2H2, -C(=O)R 10 , -C(=O)X, -C(=S)R 10 , -CO2R 10 , -CO2-, -C(=S)OR 10 , C(=O)SR 10 , C(=S)SR 10 , C(=O)NR 102 , C(=S)NR 102 or C(=NR 10 )NR 102Includes, but not limited to, where each X is independently a halogen: -F, -Cl, -Br, or -I; and each R 10 is independently -H, -C1-C 20 Alkyl, -C6-C 20 Aryl, -C3-C 14 It is a heterocyclic, protecting group, or prodrug moiety. Typical substituents also include (=O). Alkylene, carbocyclic, carbocyclo, arylene, heteroalkyl, heteroalkylene, heterocyclic, and heterocyclo groups as described above may also be similarly substituted.

[0207] Unless otherwise indicated, “polyhydroxyl group” refers to an alkyl, alkylene, carbocycline, or carbocyclo group comprising the substitution of two or more or three or more hydrogen atoms on a carbon atom of a carbon chain with hydroxyl groups. In some embodiments, the polyhydroxyl group comprises at least three hydroxyl groups. In some embodiments, the polyhydroxyl group comprises a carbon atom containing only one hydroxyl group per carbon atom. The polyhydroxyl group may contain one or more carbon atoms not substituted with hydroxyl. Each polyhydroxyl group may have a carbon atom substituted with a hydroxyl group. Examples of polyhydroxyl groups include monosaccharides in linear (non-cyclic) or cyclic forms, such as C6 or C5 sugars, such as glucose, ribose, galactose, mannose, arabinose, 2-deoxyglucose, glyceraldehyde, erythrose, threose, xylose, lixose, allose, altrose, goulose, idos, talose, aldose, and ketoses; sugar acids, such as gluconic acid, aldonic acid, uronic acid, or ulosonic acid; and amino sugars, such as glucosamine, N-acetylglucosamine, galactosamine, and N-acetylgalactosamine. In some embodiments, polyhydroxyl groups include disaccharides and polysaccharides in linear or cyclic forms.

[0208] Unless otherwise indicated by the context, “optionally substituted” refers to an alkyl, alkenyl, alkynyl, alkylaryl, arylalkyl heterocycle, aryl, heteroaryl, alkylheteroaryl, heteroarylalkyl or other substituent, moiety, or group as defined or disclosed herein, wherein the hydrogen atom(s) of the substituent, moiety, or group are optionally replaced with a different moiety(s) or group(s), or wherein a cycloaliphatic carbon chain comprising one of the substituent, moiety, or group is interposed by replacing the carbon atom(s) of the chain with a different moiety(s) or group(s). In some aspects, the alkene functional group replaces two adjacent sp3 carbon atoms of the alkyl substituent, except that the radical carbon of the alkyl moiety is not replaced, so the optionally substituted alkyl is an unsaturated alkyl substituent.

[0209] Any substituent replacing a hydrogen(s) in any one of the above substituents, moiety, or group is independently selected from the group consisting of aryl, heteroaryl, hydroxyl, alkoxy, aryloxy, cyano, halogen, nitro, fluoroalkoxy, and amino groups comprising mono-, di-, and tri-substituted amino groups and their protected derivatives, or -X, -OR' , -SR' , -NH2, -N(R')(R"), -N(R")3, =NR, -CX3, -CN, -NO2, -NR'C(=O)H, -NR'C(=O)R, -NR'C(=O)R", -C(=O)R', -C(=O)NH2, -C(=O)N(R')R", -S(=O)2R", -S(=O)2NH2, -S(=O)2N(R')R", Selected from the group consisting of -S(=O)2NH2, -S(=O)2N(R')R", -S(=O)2OR', -S(=O)R", -OP(=O)(OR')(OR"), -OP(OH)3, -P(=O)(OR')(OR"), -PO3H2, -C(=O)R', -C(=S)R", -CO2R', -C(=S)OR", -C(=O)SR', -C(=S)SR', -C(=S)NH2, -C(=S)N(R')(R")2, -C(=NR')NH2, -C(=NR')N(R')R" and their salts, wherein each X is independently selected from the group consisting of halogens: -F, -Cl, -Br, and -I; wherein each R" is C1-C 20 Alkyl, C2-C 20 Alkenyl, C2-C 20 Alkynyl, C6-C 24 Aryl, C3-C 24 Heterocyclil (C5-C 24 Including heteroaryls), independently selected from the group consisting of protecting groups and prodrug moiety, or two of R" define a heterocyclyl together with the heteroatom to which they are attached; R' is hydrogen or R", where R" is C1-C 20 Alkyl, C6-C 24 Aryl, C3-C 24 Heterocyclil (C5-C24 It is selected from the group consisting of heteroaryls and protecting groups.

[0210] Typically, arbitrary substituents are -X, -OH, -OR", -SH, -SR", -NH2, -NH(R"), -NR'(R")2, -N(R")3, =NH, =NR", -CX3, -CN, -NO2, -NR'C(=O)H, NR'C(=O)R", -CO2H, -C(=O)H, -C(=O)R", -C(=O)NH2, -C(=O)NR'R", -S(=O)2R", -S(=O)2NH2, -S(=O)2N(R')R", -S(=O)2NH2, -S(=O)2N(R')(R"), -S(=O)2OR', -S(=O)R", -C(=S)R", -C(=S)NH2, -C(=S)N(R')R", -C(=NR')N(R")2 and its salts are selected from the group consisting of -C(=S)N(R')R", -C(=NR')N(R")2 and their salts, wherein each X is independently selected from the group consisting of -F and -Cl, and R" is typically selected from the group consisting of C1-C6 alkyl, C6-C10 aryl, C3-C10 heterocyclyl (including C5-C10 heteroaryl) and a protecting group; R' is independently selected from hydrogen, C1-C6 alkyl, C6-C10 aryl, C3-C10 heterocyclyl (including C5-C10 heteroaryl) and a protecting group independently selected from R". More typically, the substituent is selected from the group consisting of -X, -R", -OH, -OR", -NH2, -NH(R"), -N(R")2, -N(R")3, -CX3, -NO2, -NHC(=O)H, -NHC(=O)R", -C(=O)NH2, -C(=O)NHR", -C(=O)N(R")2, -CO2H, -CO2R", -C(=O)H, -C(=O)R", -C(=O)NH2, -C(=O)NH(R"), -C(=O)N(R")2, -C(=NR')NH2, -C(=NR')NH(R"), -C(=NR')N(R")2, protecting groups and their salts, wherein each X is -F and R" is independently a C1-C6 alkyl, C6-C10 aryl, Selected from the group consisting of C5-C10 heteroaryls and protecting groups; R' is selected from the group consisting of hydrogen, C1-C6 alkyls and protecting groups independently selected from R".

[0211] The compounds of the present invention or their pharmaceutically acceptable salts may contain one or more asymmetric centers and thus may produce enantiomers, diastereomers, and other stereoisomer forms defined as (R) or (S) in terms of absolute stereochemistry, or (D) or (L) in the case of amino acids. The present invention is intended to include all such possible isomers, as well as their racemic and optically pure forms. Optically active (+) and ( ), (R) and (S) or (D) and (L) isomers may be prepared using chiral synthetic monomers or chiral reagents, or may be decomposed using conventional techniques, e.g., chromatography and fractional crystallization. Conventional techniques for the preparation / isolation of individual enantiomers include chiral synthesis from suitable optically pure precursors, or decomposition of racemics (or racemics of salts or derivatives) using, e.g., chiral high-pressure liquid chromatography (HPLC). Where the compounds described herein contain olefinic double bonds or other geometrically asymmetric centers, the compounds are intended to include both E and Z geometric isomers unless otherwise specified. Likewise, all tautomeric forms are also intended to be included.

[0212] "Stereoisomer" refers to a compound having different three-dimensional structures composed of the same atoms bonded by the same bond but not interchangeable. The present invention considers various stereoisomers and mixtures thereof, and includes "enantiomers," which refer to two types of stereoisomers that are mirror images of each other and whose molecules cannot be superimposed. The present invention also includes "diastereoisomers," which refer to two or more stereoisomers of a compound that have different coordinations at one or more equivalent stereocenters and are not mirror images of each other.

[0213] Although the structures presented throughout the specification are depicted with specific stereocenters, the specification should be interpreted to include variations in these stereocenters. For example, the structure of exatecan may be presented with (S,S) coordination, but the (R,S) diastereomer of exatecan is also considered to be found in distinct embodiments of the conjugate as described herein.

[0214] Unless otherwise indicated, the term “drug unit” or “drug” refers to cytotoxic agents (e.g., chemotherapy agents or drugs), immunomodulators, nucleic acids (including siRNA), growth inhibitors, toxins (e.g., proteotoxins, enzymatically active toxins of bacterial, fungal, plant or animal origin, or fragments thereof), radioisotopes, PROTACs, and other compounds that are active against these cells when delivered to target cells.

[0215] Unless otherwise indicated, the term “polymer unit” refers to a polymer moiety composed of repeating subunits. Examples of polymer units include polyamides and polyethers. In some embodiments, the polymer unit is selected from optionally substituted polyamides, substituted polyethers, or combinations thereof. In additional embodiments, the polymer unit is selected from the following:

[0216] (i) Chemical formula or an optionally substituted polyamide comprising a stereoisomer thereof, wherein each Ra is independently H or C1-6 alkyl, each Rb is independently H or C1-6 alkyl, and n0 is independently 2-26;

[0217] (ii) Chemical formula or a substituted polyether comprising its stereoisomer, wherein each Rb is independently H or C1-6 alkyl and n0 is independently 2-26; or

[0218] (iii) His combination.

[0219] Unless otherwise indicated, the term "sugar unit" or "sugar group" refers to a carbohydrate group. Examples of sugar units include glycosides.

[0220] Unless otherwise indicated, the term “carboxyl unit” or “carboxyl group” refers to a group comprising a carbonyl group [-C(O)-], a carboxyl group [-CO2H], and / or a carboxylate group [-CO2M, where M refers to a cationic counterion].

[0221] Unless otherwise indicated, the term “stretcher group” refers to a linking moiety that links a SLITRK6 binder to an enzyme-cleavable group.

[0222] Unless otherwise indicated, the term "polyamide" refers to a polymer group composed of repeating subunits containing amide bonds.

[0223] Unless otherwise indicated, the term "polyether" refers to a polymer group composed of repeating subunits containing ether bonds.

[0224] Unless otherwise indicated, the term “enzyme-cleavable group” refers to a group that is cleavable by the action of a metabolic process or reaction in the intracellular or extracellular environment, such that the covalent attachment between a drug unit (e.g., cytotoxic agent) and a linker unit or part thereof is broken, so that a free drug unit or linker unit-drug metabolite is produced and dissociated from the remainder of the linker unit.

[0225] As used herein, the phrase “pharmaceutical acceptable salt” refers to a pharmaceutically acceptable organic or inorganic salt of a compound (e.g., a linker, a drug linker, or a conjugate). The compound typically contains at least one amino group, and thus an acid addition salt with this amino group may be formed. Exemplary salts include, but are not limited to, salts of sulfate, citrate, acetate, oxalate, chloride, bromide, iodide, nitrate, bisulfate, phosphate, acid phosphate, isonicotinate, lactate, salicylate, acid citrate, tartrate, oleate, tannate, pantothenate, bitartrate, ascorbate, succinate, linoleate, gentisinate, fumarate, gluconate, glucuronate, saccharate, formate, benzoate, glutamate, methanesulfonate, ethanesulfonate, benzenesulfonate, toluenesulfonate, and pamoate (i.e., 1,1'-methylene-bis-(2-hydroxy-3-naphthoate)). A pharmaceutically acceptable salt may involve the inclusion of another molecule, such as an acetate ion, a succinate ion, or another counterion. The counterion may be any organic or inorganic moiety that stabilizes the charge on the parent compound. Additionally, a pharmaceutically acceptable salt may have more than one charged atom within its structure. If multiple charged atoms are part of the pharmaceutically acceptable salt, it may have multiple counterions. Thus, a pharmaceutically acceptable salt may have one or more charged atoms and / or one or more counterions.

[0226] As used herein, the term "essentially formed" refers to such elements required for a given embodiment. The term allows for the presence of elements that do not substantially affect the basic and novel or functional feature(s) of the embodiment.

[0227] As used herein, the term "composed of" refers to a composition, method, and each of its respective components as described herein, excluding any elements not mentioned in the description of the embodiments.

[0228] Except as examples or otherwise indicated, all numbers expressing the amount of ingredients or reaction conditions used herein shall be understood to be modified by the term “about” in all cases. When the term “about” is used in relation to a percentage, it may mean + / - 1%.

[0229] The terms "statistically significant" or "significantly" refer to statistical significance and generally mean a difference of 2 standard deviations (2SD) above or below a reference value.

[0230] Other terms are defined herein within the description of various aspects of the invention.

[0231] Antibodies and binders

[0232] A SLITRK6-binding antibody (also referred to as a SLITRK6 antibody) and its antigen-binding portion and other binders that specifically bind to human SLITRK6 are provided herein. Additionally, a conjugate of a SLITRK6 antibody, its antigen-binding portion, and other binders (also referred to as a SLITRK6 conjugate) bound to a drug, such as a cytotoxic agent or an immunomodulator, is provided herein. In some embodiments, the SLITRK6 antibody, the antigen-binding portion, other binders, and / or the SLITRK6 conjugate specifically binds to SLITRK6+ cells in a subject to reduce their number. In some embodiments, the SLITRK6 antibody, the antigen-binding portion, other binders, and / or the SLITRK6 conjugate specifically binds to SLITRK6+ cancer cells in a subject to reduce their number. In some embodiments, the SLITRK6 antibody, the antigen-binding portion, other binders, and / or the SLITRK6 conjugate specifically binds to SLITRK6+ cells associated with a disease or condition, such as cancer or an autoimmune disease, in a subject to reduce their number. In some embodiments, a SLITRK6 antibody, an antigen-binding portion, other binders and / or a SLITRK6 conjugate specifically binds to SLITRK6+ cells associated with a disease or condition in a subject, e.g., a human or animal, and reduces their number.

[0233] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have amino acid sequences presented in amino acid sequence pairs selected from SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; SEQ ID NO: 25 and SEQ ID NO: 26; and SEQ ID NO: 33 and SEQ ID NO: 34. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have amino acid sequences presented in SEQ ID NO: 1 and SEQ ID NO: 2. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 9 and SEQ ID NO: 10. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 17 and SEQ ID NO: 18. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 25 and SEQ ID NO: 26. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have the amino acid sequences presented in sequence identification number: 33 and sequence identification number: 34.

[0234] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have amino acid sequences presented in pairs of amino acid sequences selected from SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; SEQ ID NO: 25 and SEQ ID NO: 26; and SEQ ID NO: 33 and SEQ ID NO: 34, respectively; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework regions, and wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have amino acid sequences presented in pairs of amino acid sequences selected from SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; SEQ ID NO: 25 and SEQ ID NO: 26; and SEQ ID NO: 33 and SEQ ID NO: 34, respectively; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework regions, and wherein the CDR of the heavy chain or light chain variable region is not modified. The phrase "here, the CDR of the heavy or light chain variable region is not modified" refers to the fact that the VH and VL CDRs do not have amino acid substitutions, deletions, or insertions.

[0235] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have an amino acid sequence having at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% similarity with a pair of amino acid sequences selected from SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; SEQ ID NO: 25 and SEQ ID NO: 26; and SEQ ID NO: 33 and SEQ ID NO: 34. The level of similarity is each for SEQ ID NO: 1 and SEQ ID NO: 2; each for SEQ ID NO: 9 and SEQ ID NO: 10; each for SEQ ID NO: 17 and SEQ ID NO: 18; It arises from amino acid substitutions, deletions, or insertions into the VH and VL sequences presented in Sequence Identification Numbers: 25 and 26, respectively, and Sequence Identification Numbers: 33 and 34, respectively.

[0236] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 1 and SEQ ID NO: 2; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 1 and SEQ ID NO: 2; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0237] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have an amino acid sequence that is at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% identical to the sequences presented in SEQ ID NO: 1 and SEQ ID NO: 2.

[0238] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 9 and SEQ ID NO: 10; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable region (VH) and a light chain variable region (VL), wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 9 and SEQ ID NO: 10; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0239] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have an amino acid sequence that is at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% identical to the sequences presented in SEQ ID NO: 9 and SEQ ID NO: 10.

[0240] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 17 and SEQ ID NO: 18; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 17 and SEQ ID NO: 18; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0241] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have an amino acid sequence that is at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% identical to the sequences presented in SEQ ID NO: 17 and SEQ ID NO: 18.

[0242] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 25 and SEQ ID NO: 26; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 25 and SEQ ID NO: 26; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0243] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have an amino acid sequence that is at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% identical to the sequences presented in SEQ ID NO: 25 and SEQ ID NO: 26.

[0244] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 33 and SEQ ID NO: 34; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 33 and SEQ ID NO: 34; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0245] In some embodiments, the SLITRK6 antibody or its antigen-binding portion comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have an amino acid sequence that is at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% identical to the sequences presented in SEQ ID NO: 33 and SEQ ID NO: 34.

[0246] In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have amino acid sequences presented in pairs of amino acid sequences selected from SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; SEQ ID NO: 25 and SEQ ID NO: 26; and SEQ ID NO: 33 and SEQ ID NO: 34; wherein the binder specifically binds to human SLITRK6. In some embodiments, the binder comprises a heavy chain variable (VH) region and a light chain variable (VL), wherein the VH and VL regions each have SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; Each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 25 and SEQ ID NO: 26; and each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 33 and SEQ ID NO: 34; wherein the binder specifically binds to human SLITRK6 with a binding affinity higher than or similar to that of the antibody sirtratumab (lower Kd). In some embodiments, a binder comprising a heavy chain variable region (VH) and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 1 and SEQ ID NO: 2; each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 9 and SEQ ID NO: 10; each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 17 and SEQ ID NO: 18; each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 25 and SEQ ID NO: 26; and each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 33 and SEQ ID NO: 34; Here, the heavy chain and light chain variable framework regions are optionally modified with 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, and the CDR of the heavy chain or light chain variable region is not modified.In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have amino acid sequences presented in pairs of amino acid sequences selected from SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; SEQ ID NO: 25 and SEQ ID NO: 26; and SEQ ID NO: 33 and SEQ ID NO: 34; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework regions, wherein the CDR of the heavy chain or light chain variable region is not modified. As described herein, the binder comprises a SLITRK6 antibody or its antigen-binding portion(s) and optionally may comprise another peptide or polypeptide covalently attached to the SLITRK6 antibody or its antigen-binding portion. In any of these embodiments, the binder specifically binds to human SLITRK6.

[0247] In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 1 and SEQ ID NO: 2; wherein the binder specifically binds to human SLITRK6. In some embodiments, the binder comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 1 and SEQ ID NO: 2; wherein the binder specifically binds to human SLITRK6 with a binding affinity (lower Kd) that is higher than or similar to that of the antibody sirtratumab. In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 1 and SEQ ID NO: 2; Herein, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 1 and SEQ ID NO: 2; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified.

[0248] In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 9 and SEQ ID NO: 10; wherein the binder specifically binds to human SLITRK6. In some embodiments, the binder comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 9 and SEQ ID NO: 10; wherein the binder specifically binds to SLITRK6 with a higher binding affinity (lower Kd) than that of the antibody sirtratumab. In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 9 and SEQ ID NO: 10; Herein, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 9 and SEQ ID NO: 10; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified.

[0249] In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 17 and SEQ ID NO: 18; wherein the binder specifically binds to human SLITRK6. In some embodiments, the binder comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 17 and SEQ ID NO: 18; wherein the binder specifically binds to SLITRK6 with a higher binding affinity (lower Kd) than that of the antibody sirtratumab. In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 17 and SEQ ID NO: 18; Herein, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 17 and SEQ ID NO: 18; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified.

[0250] In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 25 and SEQ ID NO: 26; wherein the binder specifically binds to human SLITRK6. In some embodiments, the binder comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 25 and SEQ ID NO: 26; wherein the binder specifically binds to SLITRK6 with a higher binding affinity (lower Kd) than that of the antibody sirtratumab. In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 25 and SEQ ID NO: 26; Herein, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 25 and SEQ ID NO: 26; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified.

[0251] In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 33 and SEQ ID NO: 34; wherein the binder specifically binds to human SLITRK6. In some embodiments, the binder comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 33 and SEQ ID NO: 34; wherein the binder specifically binds to SLITRK6 with a higher binding affinity (lower Kd) than that of the antibody sirtratumab. In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 33 and SEQ ID NO: 34; Herein, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 33 and SEQ ID NO: 34; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified.

[0252] In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have amino acid sequences presented in pairs of amino acid sequences selected from SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; SEQ ID NO: 25 and SEQ ID NO: 26; and SEQ ID NO: 33 and SEQ ID NO: 34; wherein the binder specifically binds to human SLITRK6. In some embodiments, the binder comprises a heavy chain variable (VH) region and a light chain variable (VL), wherein the VH and VL regions each have SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; Each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 25 and SEQ ID NO: 26; and each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 33 and SEQ ID NO: 34; wherein the binder specifically binds to human SLITRK6 with a binding affinity higher than or similar to that of the antibody sirtratumab (lower Kd). In some embodiments, a binder comprising a heavy chain variable region (VH) and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 1 and SEQ ID NO: 2; each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 9 and SEQ ID NO: 10; each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 17 and SEQ ID NO: 18; each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 25 and SEQ ID NO: 26; and each having the amino acid sequence presented in the amino acid sequence pair selected from SEQ ID NO: 33 and SEQ ID NO: 34; Here, the heavy chain and light chain variable framework regions are optionally modified with 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, and the CDR of the heavy chain or light chain variable region is not modified.In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have amino acid sequences presented in pairs of amino acid sequences selected from SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; SEQ ID NO: 25 and SEQ ID NO: 26; and SEQ ID NO: 33 and SEQ ID NO: 34; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework regions, wherein the CDR of the heavy chain or light chain variable region is not modified. As described herein, the binder comprises a SLITRK6 antibody or its antigen-binding portion(s) and optionally may comprise another peptide or polypeptide covalently attached to the SLITRK6 antibody or its antigen-binding portion. In any of these embodiments, the binder specifically binds to human SLITRK6.

[0253] In some embodiments, a binder (e.g., an antibody) comprising a heavy chain and a light chain is provided herein, wherein the heavy chain and the light chain each comprise the amino acid sequences presented in SEQ ID NOs: 53 and 55. In some embodiments, a binder (e.g., an antibody) comprising a heavy chain and a light chain is provided herein, wherein the heavy chain and the light chain each comprise the amino acid sequences presented in SEQ ID NOs: 54 and 55. In some embodiments, a binder (e.g., an antibody) comprising a heavy chain and a light chain is provided herein, wherein the heavy chain and the light chain each comprise the amino acid sequences presented in SEQ ID NOs: 53 and 55. In some embodiments, a binder (e.g., an antibody) comprising a heavy chain and a light chain is provided herein, wherein the heavy chain and the light chain each comprise an amino acid sequence that is at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% identical to the sequences presented in SEQ ID NOs: 53 and SEQ ID NOs: 55. In some embodiments, a binder (e.g., an antibody) comprising a heavy chain and a light chain is provided herein, wherein the heavy chain and the light chain each comprise an amino acid sequence that is at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% identical to the sequences presented in SEQ ID NO: 54 and SEQ ID NO: 55. In some embodiments, a binder (e.g., an antibody) comprising a heavy chain and a light chain is provided herein, wherein the amino acid sequences of the heavy chain and the light chain each differ from SEQ ID NO: 53 and 55 by up to 1-20, 1-10, 1-5, 1-3, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 amino acid residues.In some embodiments, a binder (e.g., an antibody) comprising a heavy chain and a light chain is provided herein, wherein the amino acid sequences of the heavy chain and the light chain differ from sequence identification numbers: 54 and 55 by up to 1-20, 1-10, 1-5, 1-3, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 amino acid residues.

[0254] In some embodiments, an antibody or antigen binding portion comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 disposed in a heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 disposed in a light chain variable region framework region, and the VH and VL CDRs are each sequence identification number: 3, sequence identification number: 4, sequence identification number: 5, sequence identification number: 6, sequence identification number: 7, and sequence identification number: 8; each sequence identification number: 11, sequence identification number: 12, sequence identification number: 13, sequence identification number: 14, sequence identification number: 15, and sequence identification number: 16; Each has an amino acid sequence presented in a set of amino acid sequences selected from sequence identification number: 19, sequence identification number: 20, sequence identification number: 21, sequence identification number: 22, sequence identification number: 23 and sequence identification number: 24; each has a set of amino acid sequences selected from sequence identification number: 27, sequence identification number: 28, sequence identification number: 29, sequence identification number: 30, sequence identification number: 31 and sequence identification number: 32; and each has a set of amino acid sequences selected from sequence identification number: 35, sequence identification number: 36, sequence identification number: 37, sequence identification number: 38, sequence identification number: 39 and sequence identification number: 40. In some embodiments, each VH and VL region includes a humanization framework region. In some embodiments, each VH and VL region includes a human framework region.

[0255] In some embodiments, an antibody or antigen binding portion comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 disposed in the heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 disposed in the light chain variable region framework region, and the VH and VL CDRs each have the amino acid sequences presented in SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, and SEQ ID NO: 8. In some embodiments, each VH and VL region comprises a humanization framework region. In some embodiments, each VH and VL region comprises a human framework region.

[0256] In some embodiments, an antibody or antigen binding portion comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 located in the heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 located in the light chain variable region framework region, and the VH and VL CDRs each have the amino acid sequences presented in SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, and SEQ ID NO: 16. In some embodiments, each VH and VL region comprises a humanization framework region. In some embodiments, each VH and VL region comprises a human framework region.

[0257] In some embodiments, an antibody or antigen binding portion comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 located in the heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 located in the light chain variable region framework region, and the VH and VL CDRs each have the amino acid sequences presented in SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, and SEQ ID NO: 24. In some embodiments, each VH and VL region comprises a humanization framework region. In some embodiments, each VH and VL region comprises a human framework region.

[0258] In some embodiments, an antibody or antigen binding portion comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 located in the heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 located in the light chain variable region framework region, and the VH and VL CDRs each have the amino acid sequences presented in SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, and SEQ ID NO: 32. In some embodiments, each VH and VL region comprises a humanization framework region. In some embodiments, each VH and VL region comprises a human framework region.

[0259] In some embodiments, an antibody or antigen binding portion comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 located in the heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 located in the light chain variable region framework region, and the VH and VL CDRs each have the amino acid sequences presented in SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, and SEQ ID NO: 40. In some embodiments, each VH and VL region comprises a humanization framework region. In some embodiments, each VH and VL region comprises a human framework region.

[0260] In some embodiments, a binder is provided comprising a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 disposed in a heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 disposed in a light chain variable region framework region, and the VH and VL CDRs are each sequence number: 3, sequence number: 4, sequence number: 5, sequence number: 6, sequence number: 7, and sequence number: 8; each sequence number: 11, sequence number: 12, sequence number: 13, sequence number: 14, sequence number: 15, and sequence number: 16; Each has an amino acid sequence presented in a set of amino acid sequences selected from sequence identification number: 19, sequence identification number: 20, sequence identification number: 21, sequence identification number: 22, sequence identification number: 23 and sequence identification number: 24; each has a set of amino acid sequences selected from sequence identification number: 27, sequence identification number: 28, sequence identification number: 29, sequence identification number: 30, sequence identification number: 31 and sequence identification number: 32; and each has a set of amino acid sequences selected from sequence identification number: 35, sequence identification number: 36, sequence identification number: 37, sequence identification number: 38, sequence identification number: 39 and sequence identification number: 40. In some embodiments, each VH and VL region includes a humanization framework region. In some embodiments, each VH and VL region includes a human framework region.

[0261] In some embodiments, a binder is provided comprising a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 disposed in a heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 disposed in a light chain variable region framework region, and the VH and VL CDRs each have the amino acid sequences presented in Sequence Identification No.: 3, Sequence Identification No.: 4, Sequence Identification No.: 5, Sequence Identification No.: 6, Sequence Identification No.: 7, and Sequence Identification No.: 8. In some embodiments, each VH and VL region comprises a humanization framework region. In some embodiments, each VH and VL region comprises a human framework region.

[0262] In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 disposed in a heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 disposed in a light chain variable region framework region, and the VH and VL CDRs each have the amino acid sequences presented in SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, and SEQ ID NO: 16. In some embodiments, each VH and VL region comprises a humanization framework region. In some embodiments, each VH and VL region comprises a human framework region.

[0263] In some embodiments, a binder is provided comprising a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 disposed in a heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 disposed in a light chain variable region framework region, and the VH and VL CDRs each have the amino acid sequences presented in SEQ ID NO: 19, SEQ ID NO: 20, SEQ ID NO: 21, SEQ ID NO: 22, SEQ ID NO: 23, and SEQ ID NO: 24. In some embodiments, each VH and VL region comprises a humanization framework region. In some embodiments, each VH and VL region comprises a human framework region.

[0264] In some embodiments, a binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 disposed in a heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 disposed in a light chain variable region framework region, and the VH and VL CDRs each have the amino acid sequences presented in SEQ ID NO: 27, SEQ ID NO: 28, SEQ ID NO: 29, SEQ ID NO: 30, SEQ ID NO: 31, and SEQ ID NO: 32. In some embodiments, each VH and VL region comprises a humanization framework region. In some embodiments, each VH and VL region comprises a human framework region.

[0265] In some embodiments, a binder is provided comprising a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 disposed in a heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 disposed in a light chain variable region framework region, and the VH and VL CDRs each have the amino acid sequences presented in SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 37, SEQ ID NO: 38, SEQ ID NO: 39, and SEQ ID NO: 40. In some embodiments, each VH and VL region comprises a humanization framework region. In some embodiments, each VH and VL region comprises a human framework region.

[0266] In some embodiments, the compositions and methods described herein relate to the reduction of SLITRK6+ cells in a subject by means of an in vivo SLITRK6 antibody, its antigen-binding portion, other binders, or its conjugate (e.g., SLITRK6+ cells in cancer or tumors, or a reduction in the number of SLITRK6+ cells associated with an autoimmune disease or disorder). In some embodiments, the compositions and methods described herein relate to treating SLITRK6+ cancer in a subject by administering a SLITRK6 antibody, its antigen-binding portion, other binders, or its conjugate. In some embodiments, the compositions and methods described herein relate to treating an autoimmune disorder in a subject by administering a SLITRK6 antibody, its antigen-binding portion, other binders, or its conjugate. In some embodiments, the compositions and methods described herein relate to treating a disease or disorder associated with SLITRK6+ cells in a subject by administering a SLITRK6 antibody, its antigen-binding portion, other binders, or its conjugate. In any of these embodiments, the method further comprises reducing the number of SLITRK6+ cells in a subject associated with a disease, condition or cancer.

[0267] As used herein, the term “antibody” refers to an immunoglobulin molecule and a molecule containing the immunologically active portion of the immunoglobulin molecule, namely antigen-binding site(s) that specifically bind to an antigen, e.g., human SLITRK6. The term generally refers to an antibody composed of two immunoglobulin heavy chain variable regions and two immunoglobulin light chain variable regions, and includes full-length antibodies (having heavy chain and light chain constant regions).

[0268] Each heavy chain consists of a variable region (abbreviated as VH) and an invariant region. The heavy chain invariant region may include three domains CH1, CH2, and CH3 and optionally a fourth domain CH4. Each light chain consists of a variable region (abbreviated as VL) and an invariant region. The light chain invariant region is a CL domain. The VH and VL regions may be further subdivided into a supervariable region interspersed with conserved regions referred to as complementarity-determining regions (CDRs) and framework regions (FRs). Thus, each VH and VL region consists of three CDRs and four FRs arranged in the following order from N-terminus to C-terminus: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4. Such a structure is widely known to those skilled in the art.

[0269] As used herein, the “antigen-binding portion” of the SLITRK6 antibody refers to a portion of the SLITRK6 antibody as described herein that has the VH and VL sequences of the SLITRK6 antibody or the CDR of the SLITRK6 antibody and specifically binds to SLITRK6. Examples of antigen-binding portions include Fab, Fab', F(ab')2, Fv, scFv, disulfide-linked Fv, single-domain antibodies (also referred to as VHH, VNAR, sdAb, or nanobodies), or diabodies (see, for example, the literature incorporated herein by reference [Huston et al., Proc. Natl. Acad. Sci. USA, 85, 5879-5883 (1988) and Bird et al., Science 242, 423-426 (1988)]). As used herein, the terms Fab, F(ab')2, and Fv refer to the following: (i) a Fab fragment, i.e., a monovalent fragment consisting of VL, VH, CL, and CH1 domains; (ii) a F(ab')2 fragment, i.e., a divalent fragment consisting of two Fab fragments connected to each other at a hinge region via a disulfide crosslink; and (iii) in each case, a Fv fragment consisting of the VL and VH domains of a SLITRK6 antibody. Although the two domains of the Fv fragment, namely VL and VH, are coded by distinct coding regions, they can be further connected to each other using a synthetic linker, for example, a poly-G4S amino acid sequence ('(G4S)n' disclosed as sequence identification number 56, where n = 1 to 5), thereby making it possible to produce them as a single protein chain (where the VL and VH regions are combined to form a monovalent molecule) (known as single-chain Fv or scFv). The term "antigen-binding portion" of an antibody is also intended to include such single-chain antibodies. Other forms of single-chain antibodies, such as "diabodies," are likewise included herein.Diabadi is a divalent bispecific antibody in which the VH and VL domains are expressed on a single polypeptide chain, but are forced to pair with complementary domains on different chains (VL and VH, respectively) and form two antigen-binding sites by using a linker connecting the VH and VL domains that is too short to allow the two domains to be combined on the same chain (see, e.g., Holliger, R, et al., (1993) Proc. Natl. Acad. Sci. USA 90:64446448; Poljak, R. J, et al., (1994) Structure 2:1121-1123).

[0270] A single-domain antibody is an antibody portion consisting of a single monomeric variable antibody domain. Single-domain antibodies can be derived from the variable domains of antibody heavy chains from camels (e.g., nanobodies or VHH portions). Additionally, the term single-domain antibody includes autonomous human heavy chain variable domains (aVH) or VNAR portions derived from sharks (e.g., see reference [Hasler et al., Mol. Immunol. 75:28-37, 2016]).

[0271] Techniques for producing single-domain antibodies (e.g., DAB or VHH) are known in the art, as disclosed, for example, in the literature [Cossins et al., (2006, Prot Express Purif 51:253-259) and Li et al., (Immunol. Lett. 188:89-95, 2017)]. Single-domain antibodies can be obtained from camels, alpacas, or llamas, for example, by standard immunization techniques. (See, for example, the literature [Muyldermans et al., TIBS 26:230-235, 2001; Yau et al., J Immunol Methods 281:161-75, 2003; and Maass et al., J Immunol Methods 324:13-25, 2007]). VHH can possess potent antigen-binding capabilities and interact with novel epitopes inaccessible to conventional VH-VL pairs (e.g., see [Muyldermans et al., 2001]). Alpaca serum IgG contains approximately 50% camel heavy-chain monoligated IgG antibodies (HCAbs) (e.g., see [Maass et al., 2007]). Alpaca can be immunized with antigens, and VHH that binds to and neutralizes target antigens can be isolated (e.g., see [Maass et al., 2007]). PCR primers for amplifying alpaca VHH coding sequences have been identified, and these can be used to construct an alpaca VHH phage display library, which can be utilized for the isolation of antibody fragments by standard biopanning techniques widely known in the field (e.g., see [Maass et al., 2007]).

[0272] In some embodiments, the SLITRK6 antibody or its antigen-binding portion is part of a bispecific or multispecific binder. Bispecific and multispecific antibodies include: scFv1-ScFv2, ScFv12-Fc-scFv22, IgG-scFv, DVD-Ig, Triomab / Quadromab, Two-in-One IgG, scFv2-Fc, TandAb, and scFv-HSA-scFv. In some embodiments, IgG-scFv is IgG(H)-scFv, scFv-(H)IgG, IgG(L)-scFv, svFc-(L)IgG, 2scFV-IgG, or IgG-2scFv. For example, see references [Brinkmann and Kontermann, MAbs 9(2):182-212 (2017); Wang et al., Antibodies, 2019, 8, 43; See Dong et al., 2011, MAbs 3:273-88; Natsume et al., J. Biochem. 140(3):359-368, 2006; Cheal et al., Mol. Cancer Ther. 13(7):1803-1812, 2014; and Bates and Power, Antibodies, 2019, 8, 28.

[0273] Deformation of the VH and VL regions

[0274] With respect to the VH and VL amino acid sequences, a person skilled in the art will recognize that individual substitutions, deletions, or additions (insertions) to amino acids of the nucleic acid or polypeptide encoding VH or VL are "conservatively modified variants" that alter a single amino acid or a small percentage of amino acids in the coded sequence, wherein the alteration results in a substitution of an amino acid to a chemically similar amino acid (conservative amino acid substitution), and the modified polypeptide retains the ability to specifically bind to SLITRK6.

[0275] In some embodiments, a conservedly modified variant of the SLITRK6 antibody or its antigen-binding portion may have alteration(s) in a framework region (i.e., other than the CDR), for example, a conservedly modified variant of the SLITRK6 antibody may have amino acid sequences of VH and VL CDRs (a set of amino acid sequences (i) each of SEQ ID: 3, SEQ ID: 4, SEQ ID: 5, SEQ ID: 6, SEQ ID: 7 and SEQ ID: 8; (ii) each of SEQ ID: 11, SEQ ID: 12, SEQ ID: 13, SEQ ID: 14, SEQ ID: 15 and SEQ ID: 16; (iii) each of SEQ ID: 19, SEQ ID: 20, SEQ ID: 21, SEQ ID: 22, SEQ ID: 23 and SEQ ID: 24; (iv) each Sequence identification number: 27, sequence identification number: 28, sequence identification number: 29, sequence identification number: 30, sequence identification number: 31 and sequence identification number: 32; and (v) presented as sequence identification number: 35, sequence identification number: 36, sequence identification number: 37, sequence identification number: 38, sequence identification number: 39 and sequence identification number: 40, respectively) having at least one conservative amino acid substitution in the framework region (FR). In some embodiments, the VH and VL amino acid sequences collectively have 8 or 6 or 4 or 2 or 1 or fewer conservative amino acid substitutions in the FR compared to the amino acid sequences of the unmodified VH and VL regions. In some embodiments, the VH and VL amino acid sequences have 8 to 1, 6 to 1, 4 to 1, or 2 to 1 conservative amino acid substitutions in FR compared to the amino acid sequences of the unmodified VH and VL regions. In a further aspect of any of these embodiments, a conservatively modified variant of a SLITRK6 antibody, its antigen-binding portion, or other binder exhibits specific binding to SLITRK6.

[0276] In the case of conservative amino acid substitutions, a given amino acid may be replaced by a residue having similar physicochemical characteristics, for example, one aliphatic residue may be substituted for another (e.g., Ile, Val, Leu, or Ala to each other) or one polar residue may be substituted for another (e.g., between Lys and Arg; between Glu and Asp; or between Gln and Asn). Other such conservative amino acid substitutions, for example, substitution of the entire region having similar hydrophobic characteristics, are widely known. Polypeptides containing conservative amino acid substitutions may be tested in any one of the assays described herein to determine whether the desired activity of the natural or reference polypeptide, e.g., antigen-binding activity and specificity, i.e., for SLITRK6, is maintained.

[0277] In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder may be further optimized, for example for therapy in humans, to reduce potential immunogenicity or optimize other functional properties while maintaining functional activity. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH and VL regions each have amino acid sequences presented in pairs of amino acid sequences selected from SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; SEQ ID NO: 25 and SEQ ID NO: 26; and SEQ ID NO: 33 and SEQ ID NO: 34; Herein, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a heavy chain variable (VH) region and a light chain variable (VL) region, and the VH and VL regions each have amino acid sequences presented in amino acid sequence pairs selected from SEQ ID NO: 1 and SEQ ID NO: 2; SEQ ID NO: 9 and SEQ ID NO: 10; SEQ ID NO: 17 and SEQ ID NO: 18; SEQ ID NO: 25 and SEQ ID NO: 26; and SEQ ID NO: 33 and SEQ ID NO: 34; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0278] In some embodiments, a SLITRK6 antibody or its antigen-binding portion or other binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 1 and SEQ ID NO: 2; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, a SLITRK6 antibody or its antigen-binding portion or other binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 1 and SEQ ID NO: 2; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0279] In some embodiments, a SLITRK6 antibody or its antigen-binding portion or other binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 9 and SEQ ID NO: 10; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, a SLITRK6 antibody or its antigen-binding portion or other binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 9 and SEQ ID NO: 10; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0280] In some embodiments, a SLITRK6 antibody or its antigen-binding portion or other binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 17 and SEQ ID NO: 18; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, a SLITRK6 antibody or its antigen-binding portion or other binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 17 and SEQ ID NO: 18; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0281] In some embodiments, a SLITRK6 antibody or its antigen-binding portion or other binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 25 and SEQ ID NO: 26; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, a SLITRK6 antibody or its antigen-binding portion or other binder comprising a heavy chain variable (VH) region and a light chain variable (VL) region is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 25 and SEQ ID NO: 26; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0282] In some embodiments, a SLITRK6 antibody or its antigen-binding portion or other binder comprising a heavy chain variable region (VH) and a light chain variable region (VL) is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 33 and SEQ ID NO: 34; wherein the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 conservative amino acid substitutions in the framework region, wherein the CDR of the heavy chain or light chain variable region is not modified. In some embodiments, a binder comprising a heavy chain variable region (VH) and a light chain variable region (VL) is provided herein, wherein the VH and VL regions each have the amino acid sequences presented in SEQ ID NO: 33 and SEQ ID NO: 34; Here, the heavy chain and light chain variable framework regions are optionally modified by 1 to 8, 1 to 6, 1 to 4, or 1 to 2 amino acid substitutions, deletions, or insertions in the framework region, and here the CDR of the heavy chain or light chain variable region is not modified.

[0283] In any of these embodiments, the functional activity of the SLITRK6-binding antibody or its antigen-binding portion or other binder comprises specific binding to SLITRK6. Additional functional activity comprises depletion of SLITRK6+ cells (e.g., cancer cells or autoimmune cells). Where dose dependence exists, it does not need to be identical to that of the reference antibody or its antigen-binding portion, but rather needs to be substantially similar to or superior to the dose-dependence at a given activity compared to the reference antibody or its antigen-binding portion as described herein (i.e., the candidate polypeptide will exhibit greater activity compared to the reference antibody).

[0284] For conservative substitution, amino acids can be grouped according to similarities in the characteristics of their side chains (AL Lehninger, in Biochemistry, second ed., pp. 73-75, Worth Publishers, New York (1975)): (1) non-polar: Ala (A), Val (V), Leu (L), Ile (I), Pro (P), Phe (F), Trp (W), Met (M); (2) uncharged polar: Gly (G), Ser (S), Thr (T), Cys (C), Tyr (Y), Asn (N), Gln (Q); (3) acidic: Asp (D), Glu (E); and (4) basic: Lys (K), Arg (R), His (H).

[0285] Alternatively, for conservative substitution, naturally occurring residues can be divided into groups based on common side chain characteristics: (1) hydrophobic: norleucine, Met, Ala, Val, Leu, Ile; (2) neutral hydrophilic: Cys, Ser, Thr, Asn, Gln; (3) acidic: Asp, Glu; (4) basic: His, Lys, Arg; (5) residues affecting chain orientation: Gly, Pro; and (6) aromatic: Trp, Tyr, Phe. Non-conservative substitution will involve exchanging a member of one of these classes or a member of another class.

[0286] Certain conservative substitutions include, for example, Ala to Gly or Ser; Arg to Lys; Asn to Gln or His; Asp to Glu; Cys to Ser; Gln to Asn; Glu to Asp; Gly to Ala or Pro; His to Asn or Gln; Ile to Leu or Val; Leu to Ile or Val; Lys to Arg, Gln or Glu; Met to Leu, Tyr, or Ile; Phe to Met, Leu, or Tyr; Ser to Thr; Thr to Ser; Trp to Tyr; Tyr to Trp; and / or Phe to Val, Ile, or Leu.

[0287] In some embodiments, a conservedly modified variant of the SLITRK6 antibody or its antigen-binding portion is preferably at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or more identical to the reference VH or VL sequence, wherein the VH and VL CDRs are not modified. The degree of homology (percentage identity) between the reference sequence and the modified sequence may be determined by comparing the two sequences using, for example, a freely available computer program (e.g., BLASTp or BLASTn with default settings) commonly used for this purpose on the World Wide Web.

[0288] In some embodiments, the VH and VL amino acid sequences collectively have 8, 6, 4, 2, or 1 or fewer conservative amino acid substitutions in the framework region compared to the amino acid sequences of the unmodified VH and VL regions. In some embodiments, the VH and VL amino acid sequences collectively have 8 to 1, or 6 to 1, or 4 to 1, or 2 to 1 conservative amino acid substitutions in the framework region compared to the amino acid sequences of the unmodified VH and VL regions. In some embodiments, the VH and VL amino acid sequences collectively have 8, 6, 4, 2, or 1 or fewer amino acid substitutions, deletions, or insertions in the framework region compared to the amino acid sequences of the unmodified VH and VL regions. In some embodiments, the VH and VL amino acid sequences have 8 to 1, 6 to 1, 4 to 1, or 2 to 1 conservative amino acid substitutions in the framework region compared to the amino acid sequences of the unmodified VH and VL regions. In some embodiments, the VH and VL amino acid sequences collectively have 8 or 6 or 4 or 2 or 1 or fewer amino acid substitutions, deletions, or insertions compared to the amino acid sequences of the unmodified VH and VL regions.

[0289] Modification of the natural (or referenced) amino acid sequence may be achieved by any of the numerous techniques known to those skilled in the art. Mutations may be introduced at specific loci, for example, by synthesizing an oligonucleotide containing a desired mutant sequence flanked at a restriction site that can be ligated to a fragment of the natural sequence. After ligation, the resulting reconstructed sequence codes for a variant having the desired amino acid insertion, substitution, or deletion. Alternatively, an oligonucleotide-designation-site-specific mutagenesis procedure may be used to provide a modified nucleotide sequence having specific codons altered according to the desired substitution, deletion, or insertion. Techniques for making such modifications are very well established, and, for example, in the literature [Walder et al., (Gene 42:133, 1986); Bauer et al., (Gene 37:73, 1985); Craik (BioTechniques, January 1985, 12-19); Smith et al., (Genetic Engineering: Principles and Methods, Plenum Press, 1981)]; and including those disclosed in U.S. Patent Nos. 4,518,584 and 4,737,462, the full text of which is incorporated herein by reference.

[0290] invariant region

[0291] In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder has a fully human constant region. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder has a humanized constant region. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder has a non-human constant region. The immunoglobulin constant region refers to a heavy chain or light chain constant region. The amino acid sequences of human heavy chain and light chain constant regions are known in the art. The constant region may be any suitable type selected from the classes of immunoglobulins, IgA, IgD, IgE, IgG, and IgM. Several classes of immunoglobulins may be further divided into isoforms, for example, IgG1, IgG2, IgG3, IgG4, or IgA1 and IgA2. The heavy chain constant region (Fc) corresponding to different classes of immunoglobulins can be α, δ, ε, γ, and μ, respectively. The light chain can be one of kappa (or κ) and lambda (or λ).

[0292] In some embodiments, the constant region may have an IgG1 isoform. In some embodiments, the constant region may have an IgG2 isoform. In some embodiments, the constant region may have an IgG3 isoform. In some embodiments, the constant region may have an IgG4 isoform. In some embodiments, the Fc domain may have a hybrid isoform comprising constant regions from two or more isoforms. In some embodiments, the immunoglobulin constant region may be an IgG1 or IgG4 constant region. In some embodiments, the SLITRK6 antibody heavy chain is of the IgG1 isoform and has the amino acid sequence presented in SEQ ID NO: 49. In some embodiments, the SLITRK6 antibody heavy chain is of the IgG1 isoform and has the amino acid sequence presented in SEQ ID NO: 51. In some embodiments, the SLITRK6 antibody heavy chain is of the IgG1 isoform and has the amino acid sequence presented in SEQ ID NO: 52. In some embodiments, the SLITRK6 antibody light chain is of the kappa isoform and has the amino acid sequence presented in sequence identification number: 50.

[0293] Additionally, the SLITRK6 antibody or its antigen-binding portion or other binders may be part of a larger binder formed by the covalent or non-covalent association of the antibody or antigen-binding portion with one or more other proteins or peptides. For example, the use of a streptavidin core region to produce tetrameric scFv molecules (Kipriyanov, SM, et al., (1995), Human Antibodies and Hybridomas 6:93-101) and the use of cysteine ​​residues, marker peptides, and C-terminal polyhistidinyl peptides, e.g., hexahistidinyl tags, to produce divalent and biotinylated scFv molecules (Kipriyanov, SM, et al., (1994) Mol. Immunol. 31:10471058) are related to such binders.

[0294] The Fc region may have lysine at its C-terminus. The origin of this lysine is a naturally occurring sequence found in humans from which these Fc regions originated. During cell culture production of recombinant antibodies, this terminal lysine is cleaved by proteolysis by endogenous carboxypeptidase(s), which may produce an invariant region having the same sequence but lacking the C-terminal lysine. For the purpose of antibody production, the DNA encoding this terminal lysine may be omitted from the sequence so that the antibody is produced without lysine. Antibodies produced from nucleic acid sequences that code for or do not code for terminal lysine are substantially identical in sequence and function, for example, when using antibodies produced in a CHO-based production system, because the degree of processing of terminal lysine is typically high (Dick, LW et al., Biotechnol. Bioeng. 2008;100: 1132-1143). Accordingly, it is understood that a protein, such as an antibody, according to the present invention can be produced in a state that codes for or has terminal lysine, or not codes for or has terminal lysine. Furthermore, it is understood according to the present invention that a sequence having terminal lysine, such as an invariant region sequence having terminal lysine, can be understood as a corresponding sequence without terminal lysine, and a sequence without terminal lysine can also be understood as a corresponding sequence having terminal lysine.

[0295] Fc domain variation to change effector function

[0296] In some embodiments, the Fc region or Fc domain of the SLITRK6 antibody or its antigen-binding portion or other binder is substantially unbound to at least one Fc receptor selected from FcyRI (CD64), FcyRIIA (CD32a), FcyRIIB (CD32b), FcyRIIIA (CD16a), and FcyRIIIB (CD16b). In some embodiments, the Fc region or domain indicates that it is substantially unbound to any of the Fc receptors selected from FcyRI (CD64), FcyRIIA (CD32a), FcyRIIB (CD32b), FcyRIIIA (CD16a), and FcyRIIIB (CD16b). As used herein, “substantially unbound” refers to weak binding or no binding to the selected Fc gamma receptor or receptors. In some embodiments, “substantially unbound” refers to a reduction of at least 1,000-fold in binding affinity to the Fc gamma receptor (i.e., an increase in Kd). In some embodiments, the Fc domain or region is an Fc null. As used herein, "Fc null" refers to an Fc region or Fc domain that exhibits weak binding or no binding to any Fc gamma receptor. In some embodiments, the Fc null domain or region exhibits at least a 1,000-fold decrease in binding affinity to the Fc gamma receptor (i.e., an increase in Kd).

[0297] In some embodiments, the Fc domain has reduced effector functional activity or is substantially devoid of effector functional activity. As used herein, “effector functional activity” refers to antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and / or complement-dependent cytotoxicity (CDC). In some embodiments, the Fc domain exhibits reduced ADCC, ADCP, or CDC activity compared to the wild-type Fc domain. In some embodiments, the Fc domain exhibits a reduction in ADCC, ADCP, and CDC compared to the wild-type Fc domain. In some embodiments, the Fc domain is substantially devoid of effector function (i.e., the ability to stimulate or influence ADCC, ADCP, or CDC). As used herein, “substantially devoid of effector function” refers to a reduction of at least 1,000-fold in effector functional activity compared to the wild-type or reference Fc domain.

[0298] In some embodiments, the Fc domain has reduced or no ADCC activity. As used herein, reduced or no ADCC activity refers to a reduction of at least 10, at least 20, at least 30, at least 50, at least 100, or at least 500 times the ADCC activity of the Fc domain.

[0299] In some embodiments, the Fc domain has reduced or no CDC activity. As used herein, reduced or no CDC activity refers to a reduction of at least 10, at least 20, at least 30, at least 50, at least 100, or at least 500 times the CDC activity of the Fc domain.

[0300] Decrease / depletion of ADCC and / or CDC activity can be confirmed by performing in vitro and / or in vivo cytotoxicity assays. For example, Fc receptor (FcR) binding assays can be performed to ensure that the antibody lacks binding to the Fc-gamma receptor (and thus likely lacks ADCC activity). NK cells, which are the primary cells mediating ADCC, express only Fc-gamma RIII, whereas monocytes express Fc-gamma RII, Fc-gamma RII, and Fc-gamma RIII. FcR expression in hematopoietic cells is summarized in Table 3 on page 464 of the literature [Ravetch and Kinet, Annu. Rev. Immunol. 9:457-492 (1991)]. Non-limiting examples of in vitro assays for evaluating the ADCC activity of a molecule of interest are described in U.S. Patent No. 5,500,362 (e.g., see [Hellstrom, I. et al., Proc. Nat'l Acad. Sci. USA 83:7059-7063 (1986)]) and [Hellstrom, I et al., Proc. Nat'l Acad. Sci. USA 82:1499-1502 (1985)]; and U.S. Patent No. 5,821,337 (see [Bruggemann, M. et al., J. Exp. Med. 166:1351-1361 (1987)]). Alternatively, non-radioactive assay methods may be used (see, e.g., ACTI™ non-radioactive cytotoxicity assay for flow cytometry (CellTechnology, Inc., Mountain View, California); and Cytotox 96™ non-radioactive cytotoxicity assay (Promega, Madison, Wisconsin). Effector cells useful for these assays include peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cells. Alternatively or additionally, the ADCC activity of the molecule of interest may be determined in vivo, e.g., in the literature [Clynes et al., Proc. Nat'l Acad. Sci.It can be evaluated in animal models as disclosed in USA 95:652-656 (1998).

[0301] A C1q binding assay can also be performed to determine whether an antibody or an Fc domain or region is unable to bind to C1q and thus possesses a lack of or reduced CDC activity. For example, refer to the C1q and C3c binding ELISAs in WO 2006 / 029879 and WO 2005 / 100402. To evaluate complement activation, a CDC assay may be performed (for example, refer to the literature [Gazzano-Santoro et al., J. Immunol. Methods 202:163 (1996); Cragg, MS et al., Blood 101:1045-1052 (2003); and Cragg, MS and MJ Glennie, Blood 103:2738-2743 (2004)]).

[0302] In some embodiments, the Fc domain has reduced or no ADCP activity. As used herein, reduced or no ADCP activity refers to a reduction of at least 10, at least 20, at least 30, at least 50, at least 100, or at least 500 times the ADCP activity of the Fc domain.

[0303] ADCP binding assays may also be performed to determine whether the antibody or the Fc domain or region lacks ADCP activity or has reduced ADCP activity. For example, refer to US20190079077 and US20190048078 and the references disclosed therein.

[0304] A SLITRK6 antibody having reduced effector functional activity, or its antigen-binding portion or other binder having one or more substitutions of Fc region residues, such as 238, 265, 269, 270, 297, 327, and 329 according to the EU numbering of the kavat, for example (see, e.g., U.S. Patent No. 6,737,056). Such Fc mutants include Fc mutants having substitutions at two or more of amino acid positions 265, 269, 270, 297, and 327, including so-called "DANA" Fc mutants having substitutions to alanine at residues 265 and 297 according to the EU numbering of the kavat (see U.S. Patent No. 7,332,581). Certain antibody variants having reduced binding to FcR are also known. (See, for example, U.S. Patent No. 6,737,056; WO 2004 / 056312, and the literature [Shields et al., J. Biol. Chem. 9(2): 6591-6604 (2001)].) A SLITRK6 antibody having reduced binding to FcR, or its antigen-binding portion or other binder containing such amino acid modifications, may be prepared.

[0305] In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises an Fc domain or region having one or more amino acid substitutions that reduce Fc-gamma-R binding, e.g., substitutions at positions 234 and 235 (EU numbering of residues) of the Fc region. In some embodiments, the substitutions are L234A and L235A (LALA) according to the EU numbering of the kavat. In some embodiments, the Fc domain comprises D265A and / or P329G according to the EU numbering of the kavat in the Fc region derived from the human IgG1 Fc region. In some embodiments, the substitutions are L234A, L235A, and P329G (LALA-PG) according to the EU numbering of the kavat in the Fc region derived from the human IgG1 Fc region. (See, e.g., WO 2012 / 130831). In some embodiments, the substitutions are L234A, L235A, and D265A (LALA-DA) according to the EU numbering of the kavat in the Fc region derived from the human IgG1 Fc region. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a human IgG1 Fc region comprising the L234A mutation and the L235A mutation (LALA), wherein the amino acid positions are numbered according to the EU numbering. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a heavy chain constant region comprising the sequence presented in SEQ ID NO: 51. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a heavy chain constant region comprising the sequence presented in SEQ ID NO: 51 and a light chain constant region comprising the sequence presented in SEQ ID NO: 50. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a heavy chain invariant region comprising the sequence presented in SEQ ID No. 52.In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a heavy chain constant region comprising the sequence presented in SEQ ID NO: 52 and a light chain constant region comprising the sequence presented in SEQ ID NO: 50. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a heavy chain comprising the sequence presented in SEQ ID NO: 53. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a heavy chain comprising the sequence presented in SEQ ID NO: 53 and a light chain comprising the sequence presented in SEQ ID NO: 55. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a heavy chain comprising the sequence presented in SEQ ID NO: 54. In some embodiments, the SLITRK6 antibody or its antigen-binding portion or other binder comprises a heavy chain comprising the sequence presented in SEQ ID NO: 54 and a light chain comprising the sequence presented in SEQ ID NO: 55.

[0306] In some embodiments, as described in, for example, U.S. Patent No. 6,194,551, WO 99 / 51642 and the literature [Idusogie et al., J. Immunol. 164: 4178-4184 (2000)], changes causing altered (i.e., reduced) C1q binding and / or complement-dependent cytotoxicity (CDC) are made in the Fc region.

[0307] Method for manufacturing antibodies, antigen-binding portions, and other binding agents

[0308] In various embodiments, the SLITRK6 antibody, its antigen-binding portion, and other binders can be produced in human, murine, or other animal-derived cell lines. Recombinant DNA expression can be used to produce the SLITRK6 antibody, its antigen-binding portion, and other binders. This enables the production of the SLITRK6 antibody, as well as SLITRK6 antigen-binding portions and other binders (including fusion proteins) of a given spectrum, in selected host species. The production of the SLITRK6 antibody, its antigen-binding portion, and other binders in bacteria, yeast, transgenic animals, and eggs is also an alternative to cell-based production systems. A major advantage of transgenic animals is the potential high yield from renewable sources.

[0309] In some embodiments, a SLITRK6 VH polypeptide having the amino acid sequences presented in SEQ ID NOs: 1, 9, 17, 25, and 33 is encoded by a nucleic acid. In some embodiments, a SLITRK6 VL polypeptide having the amino acid sequences presented in SEQ ID NOs: 2, 10, 18, 26, and 34 is encoded by a nucleic acid. In some embodiments, the nucleic acid codes for a SLITRK6 VH polypeptide having the amino acid sequences presented in SEQ ID NOs: 1, 9, 17, 25, and 33. In some embodiments, the nucleic acid codes for a SLITRK6 VL polypeptide having the amino acid sequences presented in SEQ ID NOs: 2, 10, 18, 26, and 34. In some embodiments, the nucleic acid codes for a SLITRK6 VH polypeptide having the amino acid sequence presented in SEQ ID NO: 1. In some embodiments, the nucleic acid codes for a SLITRK6 VH polypeptide having the amino acid sequence presented in SEQ ID NO: 9. In some embodiments, the nucleic acid codes for a SLITRK6 VH polypeptide having the amino acid sequence presented in SEQ ID NO: 17. In some embodiments, the nucleic acid codes for a SLITRK6 VH polypeptide having the amino acid sequence presented in SEQ ID NO: 25. In some embodiments, the nucleic acid codes for a SLITRK6 VH polypeptide having the amino acid sequence presented in SEQ ID NO: 33. In some embodiments, the nucleic acid codes for a SLITRK6 VH polypeptide having the amino acid sequence presented in SEQ ID NO: 2. In some embodiments, the nucleic acid codes for a SLITRK6 VH polypeptide having the amino acid sequence presented in SEQ ID NO: 10. In some embodiments, the nucleic acid codes for a SLITRK6 VH polypeptide having the amino acid sequence presented in SEQ ID NO: 18. In some embodiments, the nucleic acid codes for the SLITRK6 VH polypeptide having the amino acid sequence presented in sequence identification number: 26.In some embodiments, the nucleic acid codes for the SLITRK6 VH polypeptide having the amino acid sequence presented in sequence identification number: 34.

[0310] In some embodiments, the nucleic acid codes for VH and VL polypeptides having the amino acid sequences presented in SEQ ID NOs: 1 and 2. In some embodiments, the nucleic acid codes for VH and VL polypeptides having the amino acid sequences presented in SEQ ID NOs: 9 and 10. In some embodiments, the nucleic acid codes for VH and VL polypeptides having the amino acid sequences presented in SEQ ID NOs: 17 and 18. In some embodiments, the nucleic acid codes for VH and VL polypeptides having the amino acid sequences presented in SEQ ID NOs: 25 and 26. In some embodiments, the nucleic acid codes for VH and VL polypeptides having the amino acid sequences presented in SEQ ID NOs: 33 and 34.

[0311] In some embodiments, the nucleic acid codes for a heavy chain polypeptide having the amino acid sequence presented in SEQ ID NO: 53. In some embodiments, the nucleic acid codes for a heavy chain polypeptide having the amino acid sequence presented in SEQ ID NO: 54. In some embodiments, the nucleic acid codes for a light chain polypeptide having the amino acid sequence presented in SEQ ID NO: 55. In some embodiments, the nucleic acid codes for heavy and light chain polypeptides having the amino acid sequences presented in SEQ ID NO: 53 and 55. In some embodiments, the nucleic acid codes for heavy and light chain polypeptides having the amino acid sequences presented in SEQ ID NO: 54 and 55.

[0312] As used herein, the terms “nucleic acid,” “nucleic acid sequence,” “polynucleotide sequence,” or “nucleotide” refer to polymer molecules incorporating units of ribonucleic acid, deoxyribonucleic acid, or analogs thereof. The nucleic acid may be single-stranded or double-stranded. Single-stranded nucleic acid may be a single strand of denatured double-stranded DNA. In some embodiments, the nucleic acid may be cDNA, for example, nucleic acid lacking introns.

[0313] Nucleic acid molecules encoding the amino acid sequence of a SLITRK6 antibody, its antigen-binding portion, as well as other binders, can be prepared by various methods known in the art. These methods include, but are not limited to, the preparation of synthetic nucleotide sequences encoding the SLITRK6 antibody, the antigen-binding portion, or other binders. Additionally, nucleotide sequences encoding the SLITRK6 antibody or the antigen-binding portion, as well as other binders, can be prepared using oligonucleotide-mediated (or site-targeted) mutagenesis, PCR-mediated mutagenesis, and cassette mutagenesis. At least the nucleic acid sequence encoding the SLITRK6 antibody, its antigen-binding portion, the binder, or its polypeptide as described herein may be recombined into vector DNA according to conventional techniques, e.g., smooth-end or staggered-end terminals for ligation, restriction enzyme digestion to provide appropriate terminals, charging to agglutinated ends where appropriate, alkaline phosphatase treatment to avoid undesirable ligation, and ligation using an appropriate ligase or other techniques known in the relevant art. Techniques for such operations, e.g., [Maniatis et al., Molecular Cloning, Lab. It is disclosed in [Manual (Cold Spring Harbor Lab. Press, NY, 1982 and 1989) and Ausubel et al., Current Protocols in Molecular Biology (John Wiley & Sons), 1987-1993)] and can be used to construct nucleic acid sequences and vectors encoding a SLITRK6 antibody or its antigen-binding portion or its VH or VL polypeptide or other binding agent.

[0314] Nucleic acid molecules, such as DNA, are referred to as being "capable of expressing" polypeptides when they contain a nucleotide sequence containing information for transcription and translation regulation, and this sequence is "operably linked" to a nucleotide sequence encoding a polypeptide. An operable link is a link in which the regulatory DNA sequence and the DNA sequence to be expressed (e.g., a SLITRK6 antibody or its antigen-binding portion or other binder) are linked in such a manner that they allow for the gene expression of polypeptide(s) or antigen-binding portions in recoverable amounts. The precise nature of the regulatory region required for gene expression may vary from organism to organism, as is widely known in similar fields. For example, see the literature [Sambrook et al., 1989; Ausubel et al., 1987–1993].

[0315] Accordingly, the expression of the SLITRK6 antibody or its antigen-binding portion described herein may occur in prokaryotic or eukaryotic cells. Suitable hosts include bacterial or eukaryotic hosts, such as in vivo or in situ yeast, insect, fungal, algal, and mammalian cells, or host cells of mammalian, insect, algal, or yeast origin. Mammalian cells or tissues may be of human, primate, hamster, rabbit, rodent, bovine, pig, sheep, horse, goat, dog, or cat origin, but any other mammalian cells may be used. Additionally, in vivo synthesis of a ubiquitin-transmembrane polypeptide fusion protein may be achieved, for example, by the use of a yeast ubiquitin hydrolase system. The fusion protein thus produced may be processed in vivo or purified and processed in vitro to enable the synthesis of the SLITRK6 antibody or its antigen-binding portion or other binders as described herein having the specified amino-terminal sequence. In addition, problems associated with the retention of start codon-derived methionine residues in direct yeast (or bacterial) expression can be avoided (see, for example, the literature [Sabin et al., 7 Bio / Technol. 705 (1989); Miller et al., 7 Bio / Technol. 698 (1989)]). Recombinant SLITRK6 antibodies, their antigen-binding portions, or other binders can be obtained using any series of yeast gene expression systems containing promoters and termination factors from actively expressed genes encoding glycolytic enzymes produced in large quantities when yeast is grown in a glucose-rich medium. Known glycolytic genes can also provide highly efficient transcriptional control signals. For example, promoter and termination factor signals of phosphoglycerate kinase genes can be utilized.

[0316] The production of SLITRK6 antibodies, their antigen-binding portions, or other binding agents in insects can be achieved, for example, by infecting an insect host with a baculovirus engineered to express a polypeptide by a method known to a person skilled in the art. See the literature [Ausubel et al., 1987-1993].

[0317] In some embodiments, the introduced nucleic acid sequence(s) (coding for a SLITRK6 antibody or its antigen-binding portion or other binder or its polypeptide) are incorporated into a plasmid or viral vector capable of autonomous replication in a recipient host cell. Any wide variety of vectors may be used for this purpose and are known and available to those skilled in the art. For example, refer to the literature [Ausubel et al., 1987-1993]. Important factors in selecting a particular plasmid or viral vector include the ease of recognizing and selecting recipient cells containing the vector from recipient cells not containing the vector; the number of copies of the vector desired in a particular host; and whether it is desirable to be able to "shuttle" the vector between host cells of different species.

[0318] Exemplary prokaryotic vectors known in the art include those capable of replicating in plasmids, e.g., E. coli. Other gene expression elements useful for the expression of DNA encoding a SLITRK6 antibody or its antigen-binding portion or other binders include (a) viral transcription promoters and their enhancer elements, e.g., SV40 early promoter (Okayama et al., 3 Mol. Cell. Biol. 280 (1983)), Rous sarcoma virus LTR (Gorman et al., 79 PNAS 6777 (1982)) and Molony murine leukemia virus LTR (Grosschedl et al., 41 Cell 885 (1985)); (b) splice regions and polyadenylation sites, e.g., derived from the late SV40 region (Okayarea et al., 1983) and (c) polyadenylation sites such as those in SV40 (Okayama et al., 1983), but not limited thereto. Immunoglobulin-coding DNA genes can be expressed using the SV40 early promoter and its enhancer, mouse immunoglobulin H chain promoter enhancer, SV40 late region mRNA splicing, rabbit S-globin interposition sequence, immunoglobulin and rabbit S-globin polyadenylation sites, and SV40 polyadenylation elements as expression elements, as described in the literature [Liu et al., below, and Weidle et al., 51 Gene 21 (1987)].

[0319] In the case of immunoglobulins encoding nucleotide sequences, the transcription promoter may be, for example, human cytomegalovirus, and the promoter enhancer may be cytomegalovirus and mouse / human immunoglobulin.

[0320] In some embodiments, for the expression of a DNA coding region in rodent cells, the transcription promoter may be a viral LTR sequence, and the transcription promoter enhancer may be either or both of a mouse immunoglobulin heavy chain enhancer and a viral LTR enhancer, and there are polyadenylation and transcription termination regions. In other embodiments, a DNA sequence coding for another protein is combined with the aforementioned expression elements to achieve protein expression in mammalian cells.

[0321] Each coding region or gene fusion is assembled in an expression vector or inserted therein. Subsequently, recipient cells capable of expressing SLITRK6 variable region(s) or its antigen-binding portion or other binders are transfected alone with a SLITRK6 antibody or antibody polypeptide or a nucleotide encoding its antigen-binding portion or other binders, or co-transfected with polynucleotide(s) encoding VH and VL chain coding regions or other binders. Transfected recipient cells are cultured under conditions allowing expression of the incorporated coding regions, and the expressed antibody chain or intact antibody or antigen-binding portion or other binders are recovered from the culture.

[0322] In some embodiments, nucleic acids containing a coding region encoding a SLITRK6 antibody or its antigen-binding portion or other binder are assembled in separate expression vectors, which are then used to co-transfect recipient host cells. Each vector may contain one or more selection genes. For example, in some embodiments, two selection genes are used: a first selection gene designed for selection in bacterial systems and a second selection gene designed for selection in eukaryotic systems, each vector having a set of coding regions. This strategy first generates a vector in bacterial systems that directs the production of a nucleotide sequence and allows for its amplification. The DNA vector thus produced and amplified in a bacterial host is subsequently used to co-transfect eukaryotic cells and to enable the selection of co-transfected cells possessing the desired transfected nucleic acid (e.g., containing the heavy and light chains of the SLITRK6 antibody). Non-limiting examples of selection genes for use in bacterial systems are genes conferring resistance to ampicillin and genes conferring resistance to chloramphenicol. Selected genes for use in eukaryotic transfectors include the xanthine guanine phosphoribosyl transferase gene (designated as gpt) and the phosphotransferase gene from Tn5 (designated as neo). Alternatively, fused nucleotide sequences encoding VH and VL chains can be assembled on the same expression vector.

[0323] For the transfection of an expression vector and the production of the SLITRK6 antibody or its antigen-binding portion or other binders, the recipient cell line may be a Chinese hamster ovary cell line (e.g., DG44) or myeloma cells. Myeloma cells can synthesize, assemble, and secrete immunoglobulin encoded by the transfected immunoglobulin gene and possess a mechanism for the glycosylation of immunoglobulin. For example, in some embodiments, the recipient cell is a recombinant Ig-producing myeloma cell SP2 / 0. SP2 / 0 cells produce only the immunoglobulin encoded by the transfected gene. Myeloma cells may be grown in a culture or within the peritoneal cavity of a mouse, whereby the secreted immunoglobulin may be obtained from ascites fluid.

[0324] An expression vector encoding the SLITRK6 antibody or its antigen-binding portion or other binding agent may be introduced into a suitable host cell by any various suitable means, including biochemical means such as transformation, transfection, protoplast fusion, calcium phosphate precipitation, and application using a polyvalent cation, e.g., diethylaminoethyl (DEAE) dextran, and mechanical means such as electroporation, direct microinjection, and microprojectile impact, as known to those skilled in the art [Johnston et al., 240 Science 1538 (1988)].

[0325] Yeast offers specific advantages over bacteria in the production of immunoglobulin heavy and light chains. Yeast performs post-translational peptide modifications, including glycosylation. There are numerous recombinant DNA strategies utilizing strong promoter sequences and high-copy number plasmids that can be used for the production of target proteins in yeast. Yeast recognizes the leader sequence of a cloned mammalian gene product and secretes a polypeptide (i.e., a pre-polypeptide) containing the leader sequence. For example, see [Hitzman et al., 11th Intl. Conf. Yeast, Genetics & Molec. Biol. (Montpelier, France, 1982)].

[0326] Yeast gene expression systems can be commercially evaluated for the levels of production, secretion, and stability of antibodies, and assembled SLITRK6 antibodies and their antigen-binding portions and other binders. Various yeast gene expression systems may be utilized, including promoters and termination factors from actively expressed genes encoding glycolytic enzymes produced in large quantities when yeast is grown in glucose-rich media. Known glycolytic genes can also provide highly efficient transcriptional control signals. For example, promoter and termination factor signals of phosphoglycerate kinase (PGK) genes may be utilized. Another example is the translation elongation factor 1 alpha promoter, e.g., from Chinese hamster cells. A number of approaches may be taken to evaluate the optimal expression plasmid for the expression of immunoglobulins in yeast. Refer to the literature [II DNA Cloning 45, (Glover, ed., IRL Press, 1985)] and, for example, US Publication No. US 2006 / 0270045 A1.

[0327] Bacterial strains may also be used as hosts for the production of antibody molecules or their antigen-binding portions or other binders as described herein. E. coli K12 strains, e. coli W3110, Bacillus species, Enterobacteria, e. Salmonella typhimurium or Serratia marcescens, and various Pseudomonas species may be used. Plasmid vectors containing replicons and control sequences derived from species compatible with the host cell are used in association with these bacterial hosts. The vectors contain replication sites as well as specific genes capable of providing phenotypic selection in the transformed cells. A number of approaches can be taken to evaluate expression plasmids for the production of SLITRK6 antibodies, their antigen-binding moiety, and other binders in bacteria (see literature [Glover, 1985; Ausubel, 1987, 1993; Sambrook, 1989; Colligan, 1992-1996]).

[0328] Host mammalian cells can be grown in vitro or in vivo. Mammalian cells provide post-translational modifications to immunoglobulin molecules, including the removal of leader peptides, folding and assembly of VH and VL chains, glycosylation of antibody molecules, and secretion of functional antibodies and / or their antigen-binding portions or other binders.

[0329] Mammalian cells that may be useful as hosts for the production of antibody proteins include, in addition to the lymphoid cells of the above description, cells of fibroblastic origin, such as Vero or CHO-K1 cells. Exemplary eukaryotic cells that may be used to express immunoglobulin polypeptides include, but are not limited to, COS cells, such as COS 7 cells; 293 cells, such as 293-6E cells; CHO cells, such as CHO--S and DG44 cells; PERC6™ cells (Crucell); and NSO cells. In some embodiments, a particular eukaryotic host cell is selected based on its ability to make desired post-translational modifications to the heavy chain and / or light chain. For example, in some embodiments, CHO cells produce polypeptides having a higher level of sialylation than the same polypeptide produced in 293 cells.

[0330] In some embodiments, one or more SLITRK6 antibodies or their antigen-binding portions or other binders may be produced in vivo in animals engineered into or transfected with one or more nucleic acid molecules encoding a polypeptide according to any suitable method.

[0331] In some embodiments, the antibody or its antigen-binding portion is produced in a cell-free system. Non-limiting exemplary cell-free systems are described, for example, in the literature [Sitaraman et al., Methods Mol. Biol. 498: 229-44 (2009); Spirin, Trends Biotechnol. 22: 538-45 (2004); and Endo et al., Biotechnol. Adv. 21: 695-713 (2003)].

[0332] Many vector systems are available for the expression of VH and VL chains in mammalian cells (see reference [Glover, 1985]). Various approaches can be followed to obtain intact antibodies. As discussed above, it is possible to achieve a complete tetrameric H2L2 antibody or its antigen-binding portion through the intracellular association and linkage of VH and VL chains by co-expressing VH and VL chains and any arbitrarily associated constant regions in the same cells. Co-expression can occur by using the same or different plasmids in the same host. Nucleic acids encoding VH and VL chains or their antigen-binding portions can be placed within the same plasmid and subsequently transfected into cells to directly select cells expressing both chains. Alternatively, cells can first be transfected with a plasmid encoding one chain, e.g., the VL chain, and then the resulting cell line can be transfected with a VH chain plasmid containing a second selection marker. Cell lines that produce an antibody, its antigen-binding portion, through any one route can be transfected with a plasmid encoding an additional copy of a peptide, VH, VL, or VH plus VL chain along with an additional selection marker to produce cell lines having enhanced characteristics, such as higher production of the assembled SLITRK6 antibody or its antigen-binding portion or other binders, or enhanced stability of the transfected cell lines.

[0333] Additionally, based on the large-scale culture of microbial or animal cells, plants have emerged as a convenient, safe, and economical alternative expression system for the production of recombinant antibodies. SLITRK6-binding antibodies, their antigen-binding portions, or other binders may be expressed in plant cell cultures or in conventionally grown plants. Expression in plants may be whole, limited to subcellular chloroplasts, or limited to seeds (endosperm). See, for example, U.S. Patent Publication No. 2003 / 0167531; U.S. Patent No. 6,080,560; U.S. Patent No. 6,512,162; and WO 0129242. Several plant-derived antibodies have reached advanced stages of development, including clinical trials (see, for example, Biolex, NC).

[0334] In the case of a non-defective antibody, the variable region (VH and VL regions) of the SLITRK6 antibody is typically linked to the immunoglobulin constant region (Fc) or at least one part of the domain, typically that of human immunoglobulin. The human constant region DNA sequence can be isolated from various human cells, e.g., immortalized B-cells, according to a widely known procedure (WO 87 / 02671). The SLITRK6 binding antibody may contain both light chain and heavy chain constant regions. The heavy chain constant region may include CH1, hinge, CH2, CH3, and optionally CH4 regions. In some embodiments, the CH2 domain may be deleted or omitted.

[0335] The technology described for the production of single-strand antibodies (e.g., U.S. Patent No. 4,946,778; see also [Bird, Science 242:423-42 (1988); Huston et al., Proc. Natl. Acad. Sci. USA 85:5879-5883 (1988); and Ward et al., Nature 334:544-54 (1989)]; the full text of which is incorporated herein by reference) can be adapted to produce single-strand antibodies that specifically bind to SLITRK6. Single-strand antibodies are formed by generating a single-strand polypeptide by linking the heavy chain and light chain variable regions of the Fv region through amino acid crosslinking. Techniques for assembling functional Fv parts in the coli can also be used (see, for example, the literature [Skerra et al., Science 242:1038-1041 (1988)]; the full text of which is incorporated herein by reference).

[0336] In some embodiments, the antigen-binding portion or other binder comprises one or more scFvs. The scFv may be a fusion protein of the variable regions of the heavy chain (VH) and light chain (VL) of an antibody, for example, linked to a short linker peptide of 10 to about 25 amino acids. The linker is typically glycine-rich for flexibility as well as serine or threonine-rich for solubility, and may link the N-terminus of the VH to the C-terminus of the VL or vice versa. Despite the removal of the constant region and the introduction of the linker, such a protein retains the specificity of the original antibody. scFv antibodies are described, for example, in the literature [Houston, JS, Methods in Enzymol. 203 (1991) 46-96]. Methods for preparing scFv molecules and designing suitable peptide linkers are, for example, U.S. Patent No. 4,704,692; U.S. Patent No. 4,946,778; It is described in the literature [Raag and Whitlow, FASEB 9:73-80 (1995) and Bird and Walker, TIBTECH, 9: 132-137 (1991)]. scFv-Fc is described in the literature [Sokolowska-Wedzina et al., Mol. Cancer Res. 15(8):1040-1050, 2017].

[0337] In some embodiments, the antigen-binding portion or other binder is a single-domain antibody, which is an antibody portion consisting of a single monomeric variable antibody domain. The single-domain antibody may be derived from the variable domain of an antibody heavy chain from camels (e.g., a nanobody or VHH portion). Additionally, the single-domain antibody may be an autonomous human heavy chain variable domain (aVH) or VNAR portion derived from sharks (e.g., see reference [Hasler et al., Mol. Immunol. 75:28-37, 2016]).

[0338] Techniques for producing single-domain antibodies (DABs or VHHs) are known in the art, for example, as disclosed in the literature [Cossins et al., (2006, Prot Express Purif 51:253-259) and Li et al., (Immunol. Lett. 188:89-95, 2017)]. Single-domain antibodies can be obtained from camels, alpacas, or llamas, for example, by standard immunization techniques. (See, for example, the literature [Muyldermans et al., TIBS 26:230-235, 2001; Yau et al., J Immunol Methods 281:161-75, 2003; and Maass et al., J Immunol Methods 324:13-25, 2007]). VHH can possess potent antigen-binding capabilities and interact with epitopes inaccessible to conventional VH-VL pairs (e.g., see [Muyldermans et al., 2001]). Alpaca serum IgG contains approximately 50% camel heavy-chain monoligated IgG antibodies (HCAbs) (e.g., see [Maass et al., 2007]). Alpaca can be immunized with antigens, and VHH that binds to and neutralizes target antigens can be isolated (e.g., see [Maass et al., 2007]). PCR primers for amplifying alpaca VHH coding sequences have been identified, and these can be used to construct an alpaca VHH phage display library, which can be used for the isolation of antibody fragments by standard biopanning techniques widely known in the field (e.g., see [Maass et al., 2007]).

[0339] Techniques for producing multispecific antibodies include, but are not limited to, the recombinant co-expression of two immunoglobulin heavy-light chain pairs having different specificities (e.g., see [Milstein and Cuello, Nature 305: 537 (1983)], WO 93 / 08829, and [Traunecker et al., EMBO J. 10: 3655 (1991)]) and “knob-in-hole” manipulation (e.g., U.S. Patent No. 5,731,168; see [Carter (2001), J Immunol Methods 248, 7-15]). Multispecific antibodies also include the manipulation of electrostatic steering effects to produce antibody Fc-heteromer molecules (e.g., see WO 2009 / 089004A1); Crosslinking of two or more antibodies or their antigen-binding portions (e.g., see U.S. Patent No. 4,676,980 and the literature [Brennan et al., Science, 229: 81 (1985)]); use of leucine zippers to produce bispecific antibodies (e.g., see the literature [Kostelny et al., J. Immunol., 148(5):1547-1553 (1992)]); use of "diabadi" technology to produce bispecific antibody portions (e.g., see the literature [Hollinger et al., Proc. Natl. Acad. Sci. USA, 90:6444-6448 (1993)]); and use of single-stranded Fv (scFv) dimers (e.g., see the literature [Gruber et al., J. Immunol., 152:5368 (1994)]); and can be produced by the preparation of a triple-specific antibody as described in the literature [Tutt et al., J. Immunol. 147: 60 (1991)], for example.

[0340] Engineered antibodies having three or more functional antigen-binding sites, including "octopus antibodies," may also be the binders (see, for example, US 2006 / 0025576A1).

[0341] In this application, binders (e.g., antibodies or antigen-binding portions) also include "dual-acting FAbs" or "DAFs" comprising antigen-binding sites that bind to two different antigens (see, e.g., US 2008 / 0069820 and reference [Bostrom et al., 2009, Science 323:1610-14]). "Crosmab" antibodies are also included herein (see, e.g., WO 2009 / 080251, WO 2009 / 080252, WO2009 / 080253, WO2009 / 080254, and WO2013 / 026833).

[0342] In some embodiments, the binder comprises different antigen-binding sites fused to one or the other of the two subunits of the Fc domain; thus, the two subunits of the Fc domain may be contained in two unequal polypeptide chains. Recombinant co-expression and subsequent dimerization of these polypeptides lead to several possible combinations of the two polypeptides. Therefore, to improve the yield and purity of bispecific molecules in recombinant production, it would be advantageous to introduce a modification into the Fc domain of the binder that promotes the association of the desired polypeptide.

[0343] Generally, this method involves replacing one or more amino acid residues with charged amino acid residues at the interface of two Fc domains so that homomerization is electrostatically unfavorable but heteromerization is electrostatically favorable.

[0344] In some embodiments, the binder is a "bispecific T cell binder" or BiTE (see, e.g., WO2004 / 106381, WO2005 / 061547, WO2007 / 042261, and WO2008 / 119567). This approach utilizes two antibody variable domains arranged on a single polypeptide. For example, a single polypeptide chain may contain two single-chain Fv (scFv) portions, each having a variable heavy chain (VH) and variable light chain (VL) domains separated by a polypeptide linker of sufficient length to allow intramolecular association between the two domains. This single polypeptide further contains a polypeptide spacer sequence between the two scFvs. Each scFv recognizes a different epitope, and these epitopes may be specific to different proteins so that both proteins are bound by the BiTE.

[0345] Since the bispecific T cell binder is a single polypeptide, it can be expressed using any prokaryotic or eukaryotic cell expression system known in the art, e.g., CHO cell lines. However, specific purification techniques (e.g., see EP1691833) may be required to separate the monomeric bispecific T cell binder from other multimeric species that may have biological activities other than the intended activity of the monomer. In one exemplary purification scheme, a solution containing the secreted polypeptide is first subjected to metal affinity chromatography and the polypeptide is eluted with an imidazole concentration gradient. This eluent is further purified using anion exchange chromatography and the polypeptide is eluted with a sodium chloride concentration gradient. Finally, this eluent is subjected to size exclusion chromatography to separate the monomer from the multimeric species. In some embodiments, the binder, which is a bispecific antibody, consists of a single polypeptide chain comprising two single-stranded FV portions (scFV) fused together by a peptide linker.

[0346] In some embodiments, the binder is multispecific, e.g., IgG-scFV. IgG-scFV formats include IgG(H)-scFV, scFv-(H)IgG, IgG(L)-scFV, svFc-(L)IgG, 2scFV-IgG, and IgG-2scFv. These and other bispecific antibody formats and methods for their preparation are described, for example, in the literature [Brinkmann and Kontermann, MAbs 9(2):182-212 (2017); Wang et al., Antibodies, 2019, 8, 43; Dong et al., 2011, MAbs 3:273-88; Natsume et al., J. Biochem. 140(3):359-368, 2006; Cheal et al., Mol. Cancer Ther. 13(7):1803-1812, 2014; and is described in Bates and Power, Antibodies, 2019, 8, 28.

[0347] IgG-like dual-variable domain antibody (DVD-Ig) is described in the literature [Wu et al., 2007, Nat Biotechnol 25:1290-97; Hasler et al., Mol. Immunol. 75:28-37, 2016] and WO 08 / 024188 and WO 07 / 024715. Triomab is described in the literature [Chelius et al., MAbs 2(3):309-319, 2010]. 2-phosphorus-1-IgG is described in the literature [Kontermann et al., Drug Discovery Today 20(7):838-847, 2015]. Tanden antibody or TandenAb is described in the same literature [Kontermann et al.]. The ScFv-HSA-scFv antibody is also described in the same literature [Kontermann et al.].

[0348] Intactless (e.g., whole) antibody, its dimer, individual light and heavy chains, or its antigen-binding portion and other binders may be recovered and purified by known techniques, e.g., immunosorbent or immunoaffinity chromatography, chromatographic methods such as HPLC (High Performance Liquid Chromatography), ammonium sulfate precipitation, gel electrophoresis, or any combination thereof. Generally, refer to the literature [Scopes, Protein Purification (Springer-Verlag, NY, 1982)]. It is advantageous to have a substantially pure SLITRK6-binding antibody or its antigen-binding portion or other binders with at least about 90% to 95% homogeneity, and particularly for pharmaceutical applications, it is advantageous to have 98% to 99% or greater homogeneity. Once purified partially or homogeneously as desired, the intactless SLITRK6 antibody or its antigen-binding portion or other binders may subsequently be used therapeutically or to develop and perform assay procedures, immunofluorescence staining, etc. Generally, refer to the literature [Vols. I & II Immunol. Meth. (Lefkovits & Pernis, eds., Acad. Press, NY, 1979 and 1981)].

[0349] Antibody-drug conjugate

[0350] In some embodiments, the SLITRK6 antibody, antigen-binding portion, or other binder as described herein is part of the SLITRK6 antibody-drug conjugate (also referred to as the SLITRK6 conjugate or SLITRK6 ADC). In some embodiments, the SLITRK6 antibody, antigen-binding portion, or other binder is attached to at least one linker, and at least one drug is attached to each linker. As used herein with respect to the conjugate, the term “drug” refers to cytotoxic agents (e.g., chemotherapy agents or drugs), immunomodulators, nucleic acids (including siRNA), growth inhibitors, toxins (e.g., proteotoxins, enzymatically active toxins of bacterial, fungal, plant or animal origin, or fragments thereof), radioisotopes, PROTACs, and other compounds that are active against target cells when delivered to such cells.

[0351] cytotoxic agents

[0352] In some embodiments, the SLITRK6 conjugate comprises at least one drug (or referred to as a “drug unit”) that is a cytotoxic agent. “Cytotoxic agent” refers to an agent having a cytotoxic effect on cells. “Cytotoxic effect” refers to the depletion, elimination, and / or death of target cell(s). Cytotoxic agents include, for example, tubulin disruptors, topoisomerase inhibitors, DNA small groove binders, and DNA alkylating agents.

[0353] Tubulin destroyers include, for example, auristatin, dolastatin, tuburisin, colchicine, vinca alkaloids, taxanes, cryptopicin, meitansinoids, hemiastellin, as well as other tubulin destroyers. Auristatin is a derivative of the natural product dolastatin. Exemplary auristatins include MMAE (N-methylvaline-valine-dolisoleuine-dolaproin-norephedrine), MMAF (N-methylvaline-valine-dolisoleuine-dolaproin-phenylalanine), and AFP (see WO2004 / 010957 and WO2007 / 008603). Other auristatin-like compounds are disclosed, for example, in published U.S. applications No. US2021 / 0008099, US2017 / 0121282, US2013 / 0309192 and US2013 / 0157960. Dolastatins include, for example, dolastatin 10 and dolastatin 15 (see, for example, literature [Pettit et al., J. Am. Chem. Soc., 1987, 109, 6883-6885; Pettit et al., Anti-Cancer Drug Des., 1998, 13, 243-277]; and published U.S. application US2001 / 0018422). Additional dolastatin derivatives considered for use herein are disclosed in U.S. Patent 9,345,785 incorporated herein by reference. In some embodiments, the tubulin destroyer is MMAE.

[0354] Tubericin includes, but is not limited to, tubericin D, tubericin M, tubephenylalanine, and tubetyrosine. WO2017 / 096311 and WO / 2016-040684 describe tubericin analogs including tubericin M.

[0355] Colchicine includes, but is not limited to, colchicine and CA-4.

[0356] Vinca alkaloids include, but are not limited to, vinblastine (VBL), vinorelbine (VRL), vincristine (VCR), and vindesin (VOS).

[0357] Taxanes include, but are not limited to, paclitaxel and docetaxel.

[0358] Cryptopicin includes, but is not limited to, cryptopicin-1 and cryptopicin-52.

[0359] Meitansinoids include, but are not limited to, meitansin, meitansinol, meitansin analogs of DM1, DM3, and DM4, and ansamatosin-2. Exemplary meitansinoid drug moiety is C-19-dechloro (U.S. Patent No. 4,256,746) (prepared by reduction of ansamatosin P2 with lithium aluminum hydride); C-20-hydroxy (or C-20-demethyl) + / -C-19-dechloro (U.S. Patent Nos. 4,361,650 and 4,307,016) (prepared by demethylation using Streptomyces or Actinomyces or dechlorination using LAH); and includes having modified aromatic rings such as C-20-demethoxy, C-20-acyloxy (--OCOR), + / -dechloro (U.S. Patent No. 4,294,757) (prepared by acylation using acyl chloride) and having modifications at other positions.

[0360] Meitansinoid drug moiety also includes C-9-SH (U.S. Patent No. 4,424,219) (prepared by the reaction of meitansinol with H2S or P2S5); C-14-alkoxymethyl (demethoxy / CH2OR) (U.S. Patent No. 4,331,598); C-14-hydroxymethyl or acyloxymethyl (CH2OH or CH2OAc) (U.S. Patent No. 4,450,254) (prepared from Nocardia); C-15-hydroxy / acyloxy (U.S. Patent No. 4,364,866) (prepared by the conversion of meitansinol by Streptomyces); C-15-methoxy (U.S. Patent Nos. 4,313,946 and 4,315,929) (isolated from Treuia nudiflora); Includes modifications such as C-18-N-demethyl (U.S. Patent Nos. 4,362,663 and 4,322,348) (prepared by demethylation of metancinol by Streptomyces); and 4,5-deoxy (U.S. Patent No. 4,371,533) (prepared by reduction of titanium trichloride / LAH of metancinol).

[0361] Hemiasterin includes, but is not limited to, hemiasterin and HTl-286.

[0362] Other tubulin destroyers include tacalonolide A, tacalonolide B, tacalonolide AF, tacalonolide AJ, tacalonolide Al-epoxide, discodermolid, epotillon A, epotillon B, and raulimalide.

[0363] In some embodiments, the cytotoxic agent may be a topoisomerase inhibitor, such as camptothecin. Exemplary camptothecins include, for example, camptothecin, irinotecan (also referred to as CPT-11), belotecan, (7-(2-(N-isopropylamino)ethyl)camptothecin), topotecan, 10-hydroxy-CPT, SN-38, exatecan, and exatecan analog DXd (see US20150297748). Other camptothecins are disclosed in WO1996 / 021666, WO00 / 08033, US2016 / 0229862, and WO2020 / 156189.

[0364] In some embodiments, the cytotoxic agent is duocarmycin, including synthetic analogs, KW-2189 and CBI-TMI.

[0365] Immunomodulators

[0366] In some embodiments, the drug is an immunomodulator. The immunomodulator may be, for example, a TLR7 and / or TLR8 agonist, a STING agonist, a RIG-I agonist, or another immunomodulator.

[0367] In some embodiments, the drug is an immunomodulator, such as a TLR7 and / or TLR8 agonist. In some embodiments, the TLR7 agonist is selected from imidazoquinoline, imidazoquinoline amine, thiazquinoline, aminoquinoline, aminoquinazolin, pyrido[3,2-d]pyrimidine-2,4-diamine, pyrimidine-2,4-diamine, 2-aminoimidazole, 1-alkyl-1H-benzimidazole-2-amine, tetrahydropyridopyrimidine, heteroarothiazide-2,2-dioxide, benzonaftyridine, guanosine analogs, adenosine analogs, thymidine homopolymers, ssRNA, CpG-A, polyG10 and polyG3. In some embodiments, the TLR7 agonist is selected from imidazoquinoline, imidazoquinoline amine, thiazquinoline, aminoquinoline, aminoquinazolin, pyrido[3,2-d]pyrimidine-2,4-diamine, pyrimidine-2,4-diamine, 2-aminoimidazole, 1-alkyl-1H-benzimidazole-2-amine, tetrahydropyridopyrimidine, heteroarothiazide-2,2-dioxide, or benzonaphthalidine. In some embodiments, the TLR7 agonist is a non-naturally occurring compound. Examples of TLR7 modulators include GS-9620, GSK-2245035, imiquimod, resiquimod, DSR-6434, DSP-3025, IMO-4200, MCT-465, MEDI-9197, 3M-051, SB-9922, 3M-052, Limtop, TMX-30X, TMX-202, RG-7863, RG-7795, and US20160168164 (Janssen), US 20150299194 (Roche), US20110098248 (Gilead Sciences), US20100143301 (Gilead Sciences), and US20090047249 (Gilead Sciences). Includes the disclosed compound.

[0368] In some embodiments, the TLR8 agonist is selected from benzazepine, imidazoquinoline, thiazoloquinoline, aminoquinoline, aminoquinazolin, pyrido[3,2-d]pyrimidine-2,4-diamine, pyrimidine-2,4-diamine, 2-aminoimidazole, 1-alkyl-1H-benzimidazole-2-amine, tetrahydropyridopyrimidine, or ssRNA. In some embodiments, the TLR8 agonist is selected from benzazepine, imidazoquinoline, thiazoloquinoline, aminoquinoline, aminoquinazolin, pyrido[3,2-d]pyrimidine-2,4-diamine, pyrimidine-2,4-diamine, 2-aminoimidazole, 1-alkyl-1H-benzimidazole-2-amine, and tetrahydropyridopyrimidine. In some embodiments, TLR8 agonists are non-naturally occurring compounds. Examples of TLR8 agonists include motolimod, resiquimod, 3M-051, 3M-052, MCT-465, IMO-4200, VTX-763, and VTX-1463.

[0369] In some embodiments, the TLR8 agonist may be any of the compounds described in WO2018 / 170179, WO2020 / 056198 and WO2020056194.

[0370] Other TLR7 and TLR8 agonists are, for example, WO2016142250, WO2017046112, WO2007024612, WO2011022508, WO2011022509, WO2012045090, WO2012097173, WO2012097177, WO2017079283, US20160008374, US20160194350, US20160289229, US Patent No. 6043238, US20180086755 (Gilead), WO2017216054 (Roche), WO2017190669 (Shanghai De Novo Pharmatech), WO2017202704 (Roche), WO2017202703 (Roche), WO20170071944 (Gilead), US20140045849 (Janssen), US20140073642 (Janssen), WO2014056953 (Janssen), WO2014076221 (Janssen), WO2014128189 (Janssen), US20140350031 (Janssen), WO2014023813 (Janssen), US20080234251 (Array Biopharma), US20080306050 (Array Biopharma), US20100029585 (Ventirx Pharma), US20110092485 (Ventirx Pharma), It is disclosed in US20110118235 (Ventirx Pharma), US20120082658 (Ventirx Pharma), US20120219615 (Ventirx Pharma), US20140066432 (Ventirx Pharma), US20140088085 (Ventirx Pharma), US20140275167 (Novira Therapeutics), and US20130251673 (Novira Therapeutics), WO2018198091 (Novartis AG), and US20170131421 (Novartis AG).

[0371] In some embodiments, the immunomodulator is a STING agonist. Examples of STING agonists include those disclosed in, for example, WO2020059895, WO2015077354, WO2020227159, WO2020075790, WO2018200812, and WO2020074004.

[0372] In some embodiments, the immunomodulator is a RIG-I agonist. Examples of RIG-I agonists include KIN1148, SB-9200, KIN700, KIN600, KIN500, KIN100, KIN101, KIN400, and KIN2000.

[0373] toxin

[0374] In some embodiments, the drug is an enzymatically active toxin or a fragment thereof, comprising, but not limited to, diphtheria A chain, an unbound active fragment of diphtheria toxin, an exotoxin A chain (derived from Pseudomonas aeruginosa), lysine A chain, abrin A chain, modesin A chain, alpha-sarsine, Aleurites fordii protein, diantin protein, Phytolaca americana protein (PAPI, PAPII, and PAP-S), momordica charantia inhibitor, cursin, crotin, sapaonaria officinalis inhibitor, gelonin, mitogelin, restrictocin, phenomycin, enomycin, and trichothecen.

[0375] radioactive isotopes

[0376] In some embodiments, the drug is a radioactive atom. Various radioisotopes are available for the production of radioconjugates. Examples include I131, I125, Y90, Re186, Re188, Sm153, Bi213, P32, Pb212, and radioisotopes of lutetium (e.g., Lu177).

[0377] PROTAC

[0378] In some embodiments, the drug is a proteolytic targeting chimera (PROTAC). PROTACs are described, for example, in published U.S. applications Nos. 20210015942, 20210015929, 20200392131, 20200216507, US20200199247 and US20190175612; the disclosures thereof are incorporated herein by reference.

[0379] Linker

[0380] A SLITRK6 conjugate typically comprises at least one linker, and each linker has at least one drug attached thereto. Typically, the conjugate comprises a linker between a SLITRK6 antibody (or its antigen-binding portion or other binder) and a drug (in some cases, referred to as a "drug unit"). In various embodiments, the linker is a protease-cleavable linker, an acid-cleavable linker, a disulfide linker, a disulfide-containing linker, or a disulfide-containing linker having a dimethyl group adjacent to a disulfide bond (e.g., SPDB linker) (e.g., see references [Jain et al., Pharm. Res. 32:3526-3540 (2015); Chari et al., Cancer Res. 52:127-131 (1992)]; U.S. Patent No. 5,208,020), a self-stabilizing linker (e.g., see WO2018 / 031690 and WO2015 / 095755 and [Jain et al., Pharm. Res. 32:3526-3540 (2015)]), a non-cleavable linker (e.g., WO2007 / 008603 It may be a photo-unstable linker (see reference), and / or a hydrophilic linker (e.g., see W02015 / 123679).

[0381] In some embodiments, the linker is a cleavable linker that is cleavable under intracellular conditions, such that cleavage of the linker causes the antibody (or its antigen-binding portion or other binder) and / or the drug from the linker to be released in an intracellular environment. For example, in some embodiments, the linker is cleavable by a cleavage agent present in an intracellular environment (e.g., within a lysosome or endosome or caveola). The linker may be a peptidyl linker that is cleavable by an intracellular peptidase or protease enzyme, including but not limited to lysosome or endosome proteases (see, for example, WO2004 / 010957, US20150297748, US2008 / 0166363, US20120328564 and US20200347075). Typically, the peptidyl linker is at least one amino acid length or at least two amino acids length. Intracellular cleavage agents may include cathepsin B and D and plasmin, all of which are known to hydrolyze dipeptide drug derivatives to cause the release of active drugs within target cells (see, e.g., Dubowchik and Walker, 1999, Pharm. Therapeutics 83:67-123). The most typical are peptidyl linkers cleavable by enzymes present in target antigen-expressing cells. For example, peptidyl linkers cleavable by cathepsin-B, a thiol-dependent protease highly expressed in cancerous tissues, may be used (e.g., Phe-Leu or Gly-Phe-Leu-Gly linkers). Other such linkers are described, for example, in U.S. Patent No. 6,214,345.In a specific embodiment, the peptidyl linker cleavable by intracellular protease is a Val-Cit linker or a Phe-Lys linker (e.g., see U.S. Patent No. 6,214,345 describing the synthesis of doxorubicin having a val-cit linker) or a Gly-Gly-Phe-Gly (Sequence Identification No.: 57) linker (e.g., see US2015 / 0297748). One advantage of using intracellular proteolytic release of a drug is that the drug is typically attenuated when conjugated, and the serum stability of the conjugate is typically high. Also refer to U.S. Patent No. 9,345,785.

[0382] As used herein, the terms "intracellularly cleaved" and "intracellularly cleaved" refer to intracellular metabolic processes or reactions for an antibody-drug conjugate in which the covalent attachment between a drug (e.g., a cytotoxic agent) and an antibody, e.g., the linker, is disrupted, causing the free drug or other metabolites of the conjugate to dissociate from the antibody within the cell. Thus, the cleaved moiety of the conjugate is an intracellular metabolite.

[0383] In some embodiments, the cleavable linker is pH-sensitive, that is, sensitive to hydrolysis at a specific pH value. Typically, the pH-sensitive linker is hydrolyzable under acidic conditions. For example, acid-unstable linkers that are hydrolyzable in lysosomes (e.g., hydrazone, semicarbazone, thiosemicarbazone, cis-aconitic acid amide, orthoester, acetal, ketal, etc.) may be used. (See, for example, U.S. Patent Nos. 5,122,368; 5,824,805; and 5,622,929; and literature [Dubowchik and Walker, 1999, Pharm. Therapeutics 83:67-123; Neville et al., 1989, Biol. Chem. 264:14653-14661].) These linkers are relatively stable under neutral pH conditions, e.g., conditions in blood, but are unstable at pH 5.5 or below 5.0, which is the approximate pH of lysosomes. In certain embodiments, the hydrolyzable linker is a thioether linker (e.g., a thioether attached to a drug via an acylhydrazone linkage (e.g., see U.S. Patent No. 5,622,929)).

[0384] In some embodiments, the linker is cleavable under reducing conditions (e.g., disulfide linker). For example, various disulfide linkers are known, including SATA (N-succinimidyl-5-acetylthioacetate), SPDP (N-succinimidyl-3-(2-pyridyldithio)propionate), SPDB (N-succinimidyl-3-(2-pyridyldithio)butyrate), and SMPT (N-succinimidyl-oxycarbonyl-alpha-methyl-alpha-(2-pyridyl-dithio)toluene), and those that can be formed using SPDB and SMPT (see, e.g., Thorpe et al., 1987, Cancer Res. 47:5924-5931; Wawrzynczak et al., In Immunoconjugates: Antibody Conjugates in Radioimagery and Therapy of Cancer (CW Vogel ed., Oxford U. Press, 1987)). Also, U.S. Patent No. Refer to 4,880,935.

[0385] In some embodiments, the linker is a malonate linker (Johnson et al., 1995, Anticancer Res. 15:1387-93), a maleimidobenzoyl linker (Lau et al., 1995, Bioorg-Med-Chem. 3(10):1299-1304), or a 3'-N-amide analog (Lau et al., 1995, Bioorg-Med-Chem. 3(10):1305-12). In some embodiments, the linker, e.g., the maleimidocaproyl linker, is not cleavable, and the drug is released by antibody degradation (see U.S. Publication No. 2005 / 0238649).

[0386] In some embodiments, the linker is not substantially susceptible to the extracellular environment. As used herein with respect to the linker, “substantially not susceptible to the extracellular environment” means that when the antibody-drug conjugate (ADC) is present in the extracellular environment (e.g., plasma), about 20% or less, typically about 15% or less, more typically about 10% or less, and more typically about 5% or less, about 3% or less, or about 1% or less of the linker is cleaved in a sample of the ADC. Whether the linker is not substantially susceptible to the extracellular environment can be determined, for example, by incubating both (a) the ADC (“ADC sample”) and (b) equimolar amounts of unconjugated antibody or drug (“control sample”) with plasma independently for a predetermined period (e.g., 2, 4, 8, 16, or 24 hours) and then comparing the amount of unconjugated antibody or drug present in the ADC sample, as measured, for example by high-performance liquid chromatography, with that present in the control sample.

[0387] In some embodiments, the linker promotes cell internalization. In some embodiments, the linker promotes cell internalization when conjugated to a drug, e.g., a cytotoxic agent (i.e., in the context of the linker-drug moiety of the ADC as described herein). In another embodiment, the linker promotes cell internalization when conjugated to both the drug and the SLITRK6 antibody (i.e., in the context of the ADC as described herein).

[0388] Various linkers that can be used with the compositions and methods of the present invention are described in WO 2004010957. In some embodiments, the protease-cleavable linker comprises a thiol-reactive spacer and a dipeptide. In some embodiments, the protease-cleavable linker consists of a thiol-reactive maleimidocaproyl spacer, a valine-citrulline dipeptide, and a p-amino-benzyloxycarbonyl spacer.

[0389] In some embodiments, the acid-cleavable linker is a hydrazine linker or a quaternary ammonium linker (see WO2017 / 096311 and WO2016 / 040684).

[0390] In some embodiments, the linker is a self-stabilizing linker comprising a maleimide group as described in U.S. Patent 9,504,756.

[0391] In some embodiments, the linker is a hydrophilic linker, e.g., the hydrophilic peptide of W02015 / 123679 and the sugar alcohol polymer-based linker disclosed in WO2013 / 012961 and WO2019 / 213046 (the full text of each of these is incorporated by reference).

[0392] In some embodiments, the binder disclosed herein may be connected to a linker such as that disclosed in WO2023280227, the full text of which is incorporated by reference.

[0393] In another embodiment, the conjugate of the SLITRK6 antibody (or antigen-binding portion or other binder) and the drug is formed with various difunctional protein coupling agents, such as N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP), succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC), iminothiolane (IT), difunctional derivatives of imidoesters (e.g., dimethyl adipimidate HCl), active esters (e.g., disuccinimidyl suberate), aldehydes (e.g., glutaraldehyde), bis-azido compounds (e.g., bis(p-azidobenzoyl)hexanediamine), bis-diazonium derivatives (e.g., bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (e.g., toluene 2,6-diisocyanate), and bis-active It can be prepared using a fluorine compound (e.g., 1,5-difluoro-2,4-dinitrobenzene). Chelating agents for the conjugation of radionucleotide(s) to an antibody, its antigen-binding portion, or other binding agent are described, for example, in WO94 / 11026.

[0394] Conjugates of SLITRK6 antibodies (or antigen-binding portions or other binders) include, but are not limited to, conjugates prepared using commercially available crosslinking agent reagents (e.g., from Pierce Biotechnology, Inc., Rockford, Illinois, USA), such as BMPS, EMCS, GMBS, HBVS, LC-SMCC, MBS, MPBH, SBAP, SIA, SIAB, SMCC, SMPB, SMPH, sulfo-EMCS, sulfo-GMBS, sulfo-KMUS, sulfo-MBS, sulfo-SIAB, sulfo-SMCC, and sulfo-SMPB, and SVSB (succinimidyl-(4-vinylsulfone)benzoate).

[0395] In some embodiments, the linker may be attached to the end of the amino acid sequence of the antibody, antigen-binding portion, or other binder, or to a side chain modification of the antibody, antigen-binding portion, or other binder, such as a side chain of lysine, serine, threonine, cysteine, tyrosine, aspartic acid, non-natural amino acid residue, glutamine, or glutamic acid residue. Attachment between the antibody, antigen-binding portion, or other binder and the linker or drug may be achieved through any of a number of bonds, for example, but not limited to amide bonds, ester bonds, ether bonds, carbon-nitrogen bonds, carbon-carbon single, double, or triple bonds, disulfide bonds, or thioether bonds. Functional groups capable of forming such bonds include, for example, amino groups, carboxyl groups, aldehyde groups, azide groups, alkynes and alkenes, carbonyl functional groups attached to leaving groups such as ketones, carbonates, cyanos, and succinimidyl, and hydroxyl groups.

[0396] In some embodiments, the linker is attached to an antibody, antigen-binding portion, or other binder at an interchain disulfide. In some embodiments, the linker is connected to an antibody, antigen-binding portion, or other binder at a hinged cysteine ​​residue. In some embodiments, the linker is attached to an antibody, antigen-binding portion, or other binder at a engineered cysteine ​​residue. In some embodiments, the linker is connected to an antibody, antigen-binding portion, or other binder at a lysine residue. In some embodiments, the linker is connected to an antibody, antigen-binding portion, or other binder at a engineered glutamine residue. In some embodiments, the linker is connected to an antibody, antigen-binding portion, or other binder at a non-natural amino acid engineered into the heavy chain.

[0397] In some embodiments, the linker is attached to the antibody, antigen-binding portion, or other binder via a sulfhydryl group. In some embodiments, the linker is attached to the antibody, antigen-binding portion, or other binder via a primary amine. In some embodiments, the linker is attached via a connection created between non-natural amino acids on the antibody, antigen-binding portion, or other binder by reacting the oxime bond formed by modifying the ketone group with an alkoxyamine on the drug.

[0398] In some embodiments, the linker is attached to an antibody, an antigen-binding portion, or other binder via a sorbase A linker. The sorbase A linker may be generated by a sorbase A enzyme that regenerates a natural amide bond by fusing an LPXTG recognition motif (SEQ ID No. 58) to an N-terminal GGG motif.

[0399] In some embodiments, the conjugate of the present disclosure comprises a SLITRK6 antibody, its antigen-binding portion, and one of other binders, at least one linker attached to the binder; at least one drug unit, wherein each drug unit is attached to the linker, wherein the linker optionally comprises at least one polar group.

[0400] In some embodiments, in the conjugate of the present disclosure, the linker is derived from a linker compound or its stereoisomer or salt, and the linker compound comprises a linker unit; a stretcher group connected to the linker unit, optionally an amino acid unit; and at least one polar group; wherein the stretcher group has an attachment site to a binder and an attachment site to an amino acid unit (if present) or a linker subunit; the amino acid unit (if present) has an attachment site to a stretcher group and an attachment site to a linker unit; and the linker unit has an attachment site to an amino acid unit (if present) or a stretcher group and at least one drug unit.

[0401] Some of the components and variations of the linker (and linker compound) are exemplified and demonstrated by the “linker embodiments” provided herein.

[0402] Enumerated modes of implementation

[0403] The linkers (and linker compounds) of the present disclosure are further illustrated by the following embodiments, which should not be construed as limiting.

[0404] Embodiment 1. A linker compound or its stereoisomer or salt comprising the following:

[0405] (a) a linker unit having 1 to 4 attachment sites for a drug unit;

[0406] (b) an amino acid unit having 1 to 12 amino acid subunits; and

[0407] (c) at least one polar group attached to an amino acid unit, wherein the polar group comprises a polymer unit, optionally a sugar unit, and optionally a carboxyl unit, wherein the polymer unit is of the following chemical formula:

[0408] ~R 0 -(R 3 -R 1 -[O-CH2-CH2] n0 -R 6 -([O-CH2-CH2]n0 -R 2 -R 3 -(NR 4 R 5 ) n1 ) n2 ) n3

[0409] (Ia)

[0410] or including its stereoisomer or salt, where:

[0411] R 0 is a functional group for attachment to the subunit of an amino acid unit;

[0412] Each R 1 and R 2 is independently bonded or C1-C6 alkylene;

[0413] Each R 3 They combine independently, C1-C 12 Alkylene, -C(O)-, -NR a -C1-C 12 Alkylene, -C1-C 12 Alkylene-NR a -, -C(O)-C1-C 12 Alkylene, -C1-C 12 Alkylene-C(O)-, -C1-C 12 Alkylene-NR a -C(O)-, -C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -NR a -C1-C 12 Alkylene-C(O)-, -C(O)-C1-C 12 Alkylene-NR a -, -NR a -C(O)-NR a -, -NR a -C(O)-, -NR a -C(O)-C1-C 12 Alkylene, -C(O)-NR a -C1-C 12 Alkylene, -heteroarylene, heteroaryl-C1-C 12 Alkylene, heteroaryl-C1-C 12Alkylene-C(O)-, -NR a -C(O)-C1-C 12 Alkylene-C(O)-, -C(O)-NR a -C1-C 12 Alkylene-(CH(OH)) 1-8 -C1-C 12 Alkylene-, -O-CH2-CH2, -OC(O)-NR a -C1-C 12 Alkylene, -O-CH2-CH(OH)-C(O)-, -O-CH2-CH(OH)-C(O)-NR a -C1-C 12 Alkylene-, -CH(OH)-, -CH(OH)-C1-C 12 Alkylene-, C1-C 12 Alkylene-CH(OH)-, -CH(OH)-C(O)-, -CH(OH)-C(O)-NR a -C1-C 12 Alkylene-, -CH(OH)-C1-C 12 Alkylene-NR a -C(O)-C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -NR a -C(O)-C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -CH(OH)-NR a -C1-C 12 Alkylene-, -[C(O)-(CH2) 1-8 -NR a ] 1-8 -, triazolyl, -C1-C 12 Alkylene-triazolyl-, -N(polyhydroxyl group- and -C(O)NR 7 R 8 Selected from, where R 7 and R 8 One of them is H or C1-C 12 It is an alkylene and the other is C1-C 12 It is an alkylene, and each R a is independently H, C 1-6Selected from alkyl, wherein any of the alkylene groups can be substituted with -SO3H;

[0414] Each R 4 and R 5 is independently H, a polyhydroxyl group, a carboxyl-containing moiety, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0415] Each R 6 It is selected from the following:

[0416] (i) , here:

[0417] Each n 3 and n 4 is independently 0-1, and

[0418] Each R b is independently H or C 1-6 It is alkyl, and

[0419] Each R 9 is independently H, acetyl, -P(=O)(OH)2, or -(CH2) v -OS(=O)2(OH) and,

[0420] Each p is independently 0-6, and

[0421] m is 1-4, and

[0422] Each v is independently 1-6, and

[0423] n 2 is 1;

[0424] (ii) , here:

[0425] Each R a is independently H or C 1-6It is alkyl, and

[0426] Each R b is independently H or C 1-6 It is alkyl, and

[0427] n 6 is 1-10, and

[0428] Each p is independently 0-6, and

[0429] n 2 is 1;

[0430] (iii) , here:

[0431] Each R a is independently H or C 1-6 It is alkyl, and

[0432] Each R b is independently H or C 1-6 It is alkyl, and

[0433] Each R 9 is independently H, acetyl, -P(=O)(OH)2, or -(CH2) v -OS(=O)2(OH) and,

[0434] Each p is independently 0-6, and

[0435] q is 1-8, and

[0436] Each v is independently 1-6, and

[0437] n 2 is 1;

[0438] (iv) , here:

[0439] Each R a is independently H or C 1-6 It is alkyl, and

[0440] Each R b is independently H or C 1-6 It is alkyl, and

[0441] Each p is independently 0-6, and

[0442] n 2 is 1;

[0443] (v) -R 10 -[O-CH2-CH2] 1-8 -R 10 -, here:

[0444] Each R b is independently H or C 1-6 It is alkyl, and

[0445] Each R 10 is independently And,

[0446] Each p is independently 1-6, and

[0447] Each R 9 is independently H, acetyl, -P(=O)(OH)2, or -(CH2) v -OS(=O)2(OH) and,

[0448] q is 1-8 and;

[0449] n 2 is 1;

[0450] (vi) -N-(R 1 -XR 2 -)2, here:

[0451] Each X is independently -NR a -C(O)- or -C(O)NR a - and,

[0452] n 2 is 2 and;

[0453] The wavy line (~) is R 0 Indicates the attachment site of the amino acid unit for;

[0454] Each n 0 is independently 2-26 and;

[0455] Each n 1 is independently 1-6 and;

[0456] n 3 It is 1-6.

[0457] Embodiment 2. A linker compound or its stereoisomer or salt comprising the following:

[0458] (a) a linker unit having 1 to 4 attachment sites for a drug unit;

[0459] (b) an amino acid unit having 1 to 12 amino acid subunits; and

[0460] (c) at least one polar group attached to an amino acid unit, wherein the polar group comprises a polymer unit, optionally a sugar unit, and optionally a carboxyl unit, wherein the polymer unit is of the following chemical formula:

[0461] ~R 0 -(R 3 -R 1 -[O-CH2-CH2] n0 -R 2 -(NR 4 R 5 ) n1 ) n3

[0462] (Ia')

[0463] or including its stereoisomer or salt, where:

[0464] R 0 is a functional group for attachment to the subunit of an amino acid unit;

[0465] Each R 1 and R 2 is independently bonded or C1-C6 alkylene;

[0466] Each R 3 It independently -N(polyhydroxyl group)-, triazolyl, -C1-C 12 Alkylene-triazolyl-,

[0467] And;

[0468] Each R 4 and R 5is independently H, a polyhydroxyl group, a carboxyl-containing moiety, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0469] Each R a is independently H or C 1-6 It is alkyl;

[0470] ( ) is R 0 R regarding 3 Indicates the attachment site of,

[0471] wavy line ( ) is R 1 R regarding 3 Indicates the attachment site of;

[0472] Each p is 1-6 and;

[0473] Each n 0 is independently 2-8 and;

[0474] Each n 1 is independently 1-6 and;

[0475] n 3 It is 1-6.

[0476] Embodiment 3. A linker compound or its stereoisomer or salt comprising the following:

[0477] (a) a linker unit having 1 to 4 attachment sites for a drug unit;

[0478] (b) an amino acid unit having 1 to 12 amino acid subunits; and

[0479] (c) at least one polar group attached to an amino acid unit, wherein the polar group comprises a polymer unit, optionally a sugar unit, and optionally a carboxyl unit, wherein the polymer unit is of the following chemical formula:

[0480] ~R 0 -(R 1 -[O-CH2-CH2] n0 -R 2 -R 3 -(NR 4 R 5 ) n1 ) n3

[0481] (Ia)

[0482] or including its stereoisomer or salt, where:

[0483] (i) R 0 is a functional group for attachment to the subunit of an amino acid unit;

[0484] Each R 1 and R 2 is independently bonded or C1-C6 alkylene;

[0485] R 3 is -C(O)- and;

[0486] R 4 is H and;

[0487] R 5 is independently a polyhydroxyl group, a carboxyl-containing moiety, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and

[0488] The wavy line (~) is R 0 Indicates the attachment site of the amino acid unit for;

[0489] n 0 is independently 2-26 and;

[0490] n1 is 1-6 and;

[0491] n 3 is 1-6 or;

[0492] (ii) R 0 is -C(O)- and;

[0493] R 1 , R 2 and R 3 Each is a combination;

[0494] R 4 and R 5 is each independently H, a polyhydroxyl group, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0495] The wavy line (~) is R 0 Indicates the attachment site of the amino acid unit for;

[0496] n 0 It is 6 and;

[0497] n 1 is 1-6 and;

[0498] n 3 is 1 or;

[0499] (iii) R 0 is a functional group for attachment to the subunit of an amino acid unit;

[0500] R 1 and R 2 Each is independently bonded to a C1-C6 alkylene;

[0501] R 3 -NR a -C(O)-C1-C 12 Alkylene-C(O)-, where the alkylene is substituted with -SO3H;

[0502] R a is H or C 1-6 It is alkyl;

[0503] R 4 and R 5 is each independently H, a carboxyl-containing moiety, a polyhydroxyl group, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0504] The wavy line (~) is R 0 Indicates the attachment site of the amino acid unit for;

[0505] Each n 0 is independently 1-26 and;

[0506] n 1 is 1-6 and;

[0507] n 3 is 1-6 or; or

[0508] (iv) R 0 silver And;

[0509] Each R 1 is independently bonded or C1-C6 alkylene;

[0510] R 2 and R 3 Each is a combination;

[0511] R 4 and R 5is each independently H, a polyhydroxyl group, a carboxyl-containing moiety, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0512] Each R a is independently H or C 1-6 It is alkyl;

[0513] wavy line ( ) is R for the remainder of the polymer unit 0 Indicates the attachment site of;

[0514] The wavy line (~*) is R 0 Indicates the attachment site of the amino acid unit for;

[0515] n 0 is 1-8 and;

[0516] n 1 is 1-6 and;

[0517] n 3 It is 2.

[0518] Embodiment 4. A linker compound or its stereoisomer or salt comprising the following:

[0519] (a) A linker unit having 1 to 4 attachment sites to a drug unit, said linker unit having a moiety of the following chemical formula:

[0520] ,

[0521] or includes its stereoisomer or salt, where:

[0522] α- represents a direct or indirect attachment site to an amino acid unit;

[0523] δ- indicates an attachment site for at least one of the drug units or for a linker attached to at least one of the drug units;

[0524] R a is H or C 1-6 alkyl;

[0525] (b) an amino acid unit having 1 to 12 amino acid subunits; and

[0526] (c) at least one polar group attached to an amino acid unit, wherein the polar group comprises a polymer unit, optionally a sugar unit, and optionally a carboxyl unit.

[0527] Embodiment 5. A linker compound or its stereoisomer or salt comprising the following:

[0528] (a) a linker unit having 1 to 4 attachment sites for a drug unit;

[0529] (b) an amino acid unit having 1 to 12 amino acid subunits; and

[0530] (c) at least one polar group attached to an amino acid unit, wherein the polar group comprises a polymer unit, optionally a sugar unit, and optionally a carboxyl unit, wherein the polymer unit comprises the following:

[0531] (i) Chemical formula or an optionally substituted polyamide comprising its stereoisomer, wherein each R a is independently H or C 1-6 It is alkyl, and each R b is independently H or C 1-6 It is alkyl, and n 0 is independently 2-26;

[0532] (ii) Chemical formula or a substituted polyether comprising its stereoisomer, wherein each R b is independently H or C 1-6 It is alkyl, and n 0is independently 2-26; or

[0533] (iii) His combination.

[0534] Embodiment 6. In Embodiment 4 or 5, at least one polar group attached to an amino acid unit has the following chemical formula:

[0535] ~R 0 -(R 3 -R 1 -[O-CH2-CH2] n0 -R 6 -([O-CH2-CH2] n0 -R 2 -R 3 -(NR 4 R 5 ) n1 ) n2 ) n3

[0536] (Ia)

[0537] ~R 0 -(R 3 -R 1 -[O-CH2-CH(OH)-CH2] n0 -R 6 -[O-CH2-CH(OH)-CH2] n0 -R 2 -R 3 -(NR 4 R 5 ) n1 ) n3

[0538] (Ib)

[0539] or

[0540]

[0541] or including its stereoisomer or salt, where:

[0542] R 0 is a functional group for attachment to the subunit of an amino acid unit;

[0543] Each R 1 and R 2 is independently bonded or C1-C6 alkylene;

[0544] Each R3 They combine independently, C1-C 12 Alkylene, -C(O)-, -NR a -C1-C 12 Alkylene, -C1-C 12 Alkylene-NR a -, -C(O)-C1-C 12 Alkylene, -C1-C 12 Alkylene-C(O)-, -C1-C 12 Alkylene-NR a -C(O)-, -C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -NR a -C1-C 12 Alkylene-C(O)-, -C(O)-C1-C 12 Alkylene-NR a -, -NR a -C(O)-NR a -, -NR a -C(O)-, -NR a -C(O)-C1-C 12 Alkylene, -C(O)-NR a -C1-C 12 Alkylene, -heteroarylene, heteroaryl-C1-C 12 Alkylene, heteroaryl-C1-C 12 Alkylene-C(O)-, -NR a -C(O)-C1-C 12 Alkylene-C(O)-, -C(O)-NR a -C1-C 12 Alkylene-(CH(OH)) 1-8 -C1-C 12 Alkylene-, -O-CH2-CH2, -OC(O)-NR a -C1-C 12 Alkylene, -O-CH2-CH(OH)-C(O)-, -O-CH2-CH(OH)-C(O)-NR a -C1-C 12 Alkylene-, -CH(OH)-, -CH(OH)-C1-C 12 Alkylene-, C1-C 12 Alkylene-CH(OH)-, -CH(OH)-C(O)-, -CH(OH)-C(O)-NR a-C1-C 12 Alkylene-, -CH(OH)-C1-C 12 Alkylene-NR a -C(O)-C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -NR a -C(O)-C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -CH(OH)-NR a -C1-C 12 Alkylene-, -[C(O)-(CH2) 1-8 -NR a ] 1-8 -, triazolyl, -C1-C 12 Alkylene-triazolyl-, and -C(O)NR 7 R 8 Selected from, where R 7 and R 8 One of them is H or C1-C 12 It is an alkylene and the other is C1-C 12 It is an alkylene, and each R a is independently H, C 1-6 Selected from alkyl, wherein any of the alkylene groups can be substituted with -SO3H;

[0545] Each R 4 and R 5 is independently H, a polyhydroxyl group, a carboxyl-containing moiety, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl-ether group, a substituted polyhydroxyl-ether group, or a chelating agent, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, and R 4 and R 5 At least one of them is not H;

[0546] Each R 6 is a linker compound that is independently bonded or selected from the following:

[0547] (i) , here:

[0548] Each n 3 and n 4 is independently 0-1, and

[0549] Each R b is independently H or C 1-6 It is alkyl, and

[0550] Each R 9 is independently H, acetyl, -P(=O)(OH)2, or -(CH2) v -OS(=O)2(OH) and,

[0551] Each p is independently 0-6, and

[0552] m is 1-4, and

[0553] Each v is independently 1-6, and

[0554] n 2 is 1;

[0555] (ii) , here:

[0556] Each R a is independently H or C 1-6 It is alkyl, and

[0557] Each R b is independently H or C 1-6 It is alkyl, and

[0558] n 6 is 1-10, and

[0559] Each p is independently 0-6, and

[0560] n 2 is 1;

[0561] (iii) , here:

[0562] Each R a is independently H or C 1-6 It is alkyl, and

[0563] Each R b is independently H or C 1-6It is alkyl, and

[0564] Each R 9 is independently H, acetyl, -P(=O)(OH)2, or -(CH2) v -OS(=O)2(OH) and,

[0565] Each p is independently 0-6, and

[0566] q is 1-8, and

[0567] Each v is independently 1-6, and

[0568] n 2 is 1;

[0569] (iv) , here:

[0570] Each R a is independently H or C 1-6 It is alkyl, and

[0571] Each R b is independently H or C 1-6 It is alkyl, and

[0572] Each p is independently 0-6, and

[0573] n 2 is 1;

[0574] (v) -R 10 -[O-CH2-CH2] 1-8 -R 10 -, here:

[0575] Each R b is independently H or C 1-6 It is alkyl, and

[0576] Each R 10 is independently And,

[0577] Each p is independently 1-6, and

[0578] q is 1 to 8;

[0579] (vi) -N-(R 1 -XR 2 -[O-CH2-CH2] n0 -R 2-R 3 -(NR 4 R 5 ) n1 )2, here:

[0580] Each X is independently -NR a -C(O)- or -C(O)NR a - and,

[0581] n 2 is 2 and;

[0582] The wavy line (~) is R 0 Indicates the attachment site of the amino acid unit for;

[0583] Each n 0 is independently 2-26 and;

[0584] n 1 is 0-6, and n 1 If this is 0, R 3 -OH or -C(O)OR b and, here R b is independently H or C 1-6 It is alkyl;

[0585] n 3 It is 1-6.

[0586] Embodiment 7. In any one of Embodiments 1 and 4-6, each R 3 This combines independently, -C(O)-, -NR a -C(O)-C1-C 12 Alkylene-C(O)-, -C(O)-NR a -C1-C 12 Alkylene-(CH(OH)) 1-8 -C1-C 12 Alkylene-, -O-CH2-CH(OH)-C(O)-, -O-CH2-CH(OH)-C(O)-NR a - C1-C 12 Alkylene-, -CH(OH)-, -CH(OH)-C1-C 12 Alkylene-, C1-C 12 Alkylene-CH(OH)-, -CH(OH)-C(O)-, -CH(OH)-C(O)-NR a -C1-C 12Alkylene-, -CH(OH)-C1-C 12 Alkylene-NR a -C(O)-C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -NR a -C(O)-C1-C 12 Alkylene-C(O)-NR a -C1-C 12 Alkylene-, -CH(OH)-NR a -C1-C 12 Alkylene-, -[C(O)-(CH2) 1-8 -NR a ] 1-8 -, triazolyl, and -C1-C 12 Selected from alkylene-triazolyl-, -N(polyhydroxyl group)-, and each R a H, C independently 1-6 A linker compound selected from alkyl; wherein any of the alkylene groups can be substituted with -SO3H.

[0587] Embodiment 8. In any one of embodiments 1-3 and 5-7, the linker unit is a moiety selected from the following:

[0588]

[0589] or includes its stereoisomer or salt, where:

[0590] α- represents a direct or indirect attachment site to an amino acid unit;

[0591] δ- represents an attachment site for at least one of the drug units or an attachment site for a linker attached to at least one of the drug units;

[0592] R a is H or C 1-6 Alkyl linker compound.

[0593] Embodiment 9. A linker compound or its stereoisomer or salt comprising the following:

[0594] (a) A linker unit having 1 to 4 attachment sites to a drug unit and having one of the following structures (i) or (ii):

[0595] ;

[0596] (b) at least one polar group comprising a polymer unit, optionally a sugar unit, optionally a carboxyl unit, and a combination thereof; and

[0597] (c) A stretcher device having an optional attachment site for a SLITRK6 binder;

[0598] Here:

[0599] α- is an attachment site for an enzyme-cleavable group;

[0600] β- is an attachment site for at least one polar group;

[0601] δ- is H, an attachment site for at least one of the drug units or an attachment site for a linker attached to at least one of the drug units;

[0602] The polymer unit comprises a polyamide, a polyether, or a combination thereof, wherein the polyether comprises a hydroxyl group, a polyhydroxyl group, a sugar group, a carboxyl group, or a combination thereof;

[0603] Each R a is independently H or C1-C6 alkyl;

[0604] Each R b is independently an attachment site for at least one of a halo, C1-6 alkyl, or drug unit, or an attachment site for at least one of a polar group;

[0605] x is 0, 1, 2, 3, or 4;

[0606] y is 0, 1, 2, or 3, and;

[0607] R c is a bond, -C(O)-, -S(O)-, -SO2-, C1-6alkylene, C 1-6It is alkynylene, triazolyl, or a combination thereof;

[0608] Y is bonded, -O-, -S-, -N(R a )-, -C(O)-, -S(O)-, -SO2-C1-C6alkylene, C1-C6alkenylene, C1-C6alkynylene, triazolyl, a group containing triazolyl or a combination thereof.

[0609] Embodiment 10. In Embodiment 9, the linker unit comprises one of the following structures (ia), (ii-a), or (iii-a):

[0610]

[0611] A linker compound having its stereoisomer or salt.

[0612] Embodiment 11. In Embodiment 9 or 10, the linker unit is one of the following structures (ib), (ic), (id), (ie) or (if):

[0613]

[0614] A linker compound having its stereoisomer or salt.

[0615] Embodiment 12. In Embodiment 9, the linker unit has the following structure (ii-b) or (iii-b):

[0616]

[0617] A linker compound having its stereoisomer or salt.

[0618] Embodiment 13. In any one of Embodiments 9-12, the polar group has the following chemical formula:

[0619] L3-N(CH2- (CH(XR)) k - X1(X2))2(X)

[0620] or comprising at least one sugar unit having its stereoisomer or salt, where:

[0621] Each X is independently selected from NH and O;

[0622] Each R is independently selected from hydrogen, acetyl, monosaccharides, disaccharides, and polysaccharides;

[0623] Each X1 is independently selected from CH2 and C(O);

[0624] Each X2 is independently selected from H, OH, and OR;

[0625] k is 1 to 10 and;

[0626] L3 is a linker compound that is the attachment point for the remainder of the polar groups.

[0627] Embodiment 14. In Embodiment 13, at least one unit is one of the following structures (XII) or (XIII):

[0628]

[0629] or having its stereoisomer or salt, where:

[0630] Each R is independently selected from hydrogen, monosaccharides, disaccharides, and polysaccharides;

[0631] m is 1 to 8;

[0632] n is a linker compound of 0 to 4.

[0633] Embodiment 15. A linker compound in which, in any one of Embodiments 1-14, the polar group has a chemical formula selected from the following:

[0634] (a) ~R 20 -R 21 -[O-CH2-CH2] n20 -R 22 -NR 24 R 25 (XX)

[0635] or his stereoisomer salt, where:

[0636] R 20 It is site β or site Rb or an attachment group to an enzyme-cleavable group;

[0637] R 21 and R 22 Each is independently bonded to a C1-C3 alkylene;

[0638] R 24 and R 25 Each is independently H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; optionally substituted C3-C 10 Carbocycle; optionally substituted C1-C3 alkylene C3-C 10 Carbocycle; optionally substituted heteroaryl; optionally substituted carbocycle; substituted -C1-C8 alkyl; substituted -C(O)-C1-C8 alkyl; chelating agent; and R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 ; or together -NR 24 R 25 Selected from those forming a C3-C8 heterocycle;

[0639] n20 is 2 to 26; or

[0640] (b) ~R 20 -R 21 -[O-CH2-CH2] n20 -R 22 -NR 24 R 25 (XXI)

[0641] or his stereoisomer or salt, where:

[0642] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0643] R 21 and R 22 Each is independently bonded to a C1-C3 alkylene;

[0644] R 24 and R 25One of them is H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; optionally substituted C3-C 10 Carbocycle; optionally substituted C1-C3 alkylene C3-C 10 Carbocycle; optionally substituted heteroaryl; optionally substituted carbocycle; substituted -C1-C8 alkyl; substituted -C(O)-C1-C8 alkyl; chelating agent; and R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 Selected from; R 24 and R 25 The other one is optionally a polyethylene glycol having 1 to 24 ethylene glycol subunits;

[0645] n20 is 2 to 26; or

[0646] (c) ~R 20 -[-R 26 -[R 29 -[O-CH2-CH2-] n20 R 29 ] n21 -R 27 -NR 24 R 25 ] n27 (XXII)

[0647] or his stereoisomer or salt, where:

[0648] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0649] R 26 and R 27 Each combines arbitrarily and independently, C1-C 12 Alkylene, -NH-C1-C 12 Alkylene, -C1-C 12 Alkylene-NH-, -C1-C 12 Alkylene-N(CH3)-, -C(O)-C1-C 12 Alkylene, -C1-C 12Alkylene-C(O)-, -NH-C1-C 12 Alkylene-C(O)- and -C(O)-C1-C 12 Selected from alkylene-NH-;

[0650] R 24 and R 25 One of them is H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; optionally substituted C3-C 10 Carbocycle; optionally substituted C1-C3 alkylene C3-C 10 Carbocycle; optionally substituted heteroaryl; optionally substituted carbocycle; substituted -C1-C8 alkyl; substituted -C(O)-C1-C8 alkyl; chelating agent; R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 Selected from; R 24 and R 25 The other one is H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; optionally substituted C3-C 10 Carbocycle; optionally substituted C1-C3 alkylene C3-C 10 Carbocycle; optionally substituted heteroaryl; optionally substituted carbocycle; substituted -C1-C8 alkyl; substituted -C(O)-C1-C8 alkyl; chelating agent; and R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 ; and optionally polyethylene glycol having 1 to 24 ethylene glycol subunits; or together with -NR 24 R 25 Selected from those forming a C3-C8 heterocycle;

[0651] Each R 29is optionally and independently selected from -C(O)-, -NH-, -C(O)-C1-C6alkylene-, -NH-C1-C6alkylene-, -C1-C6alkylene-NH-, -C1-C6alkylene-C(O)-, -NH(CO)-C1-C6alkylene-, -N(CH3)-(CO)-C1-C6alkylene-, -NH(CO)NH-, and triazole;

[0652] n20 is 2 to 26;

[0653] n21 is 1 to 4;

[0654] n27 is 1 to 4, or

[0655] (d) ~R 20 -R 21 -[-C(R α )HC(O)-N(R N )-] n20 -R 22 -NR 24 R 25 (XXIII)

[0656] or his stereoisomer or salt, where:

[0657] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0658] R 21 Silver bond, C1-C3 alkylene, -C1-C3 alkylene-[O-CH2-CH2-] n20 , -[CH2-CH2-O] n20 -C1-C3alkylene- or -C1-C3alkylene-[O-CH2-CH2-] n20 -C(O)- and;

[0659] R 22 is C1-C3 alkylene, -C1-C3 alkylene-[O-CH2-CH2-] n20 , -[CH2-CH2-O] n20 -C1-C3alkylene- or -C1-C3alkylene-[O-CH2-CH2-] n20 -C(O)- and;

[0660] Each R αis independently H or -R 22 -NR 24 R 25 And;

[0661] Each R N is independently H, C1-C6 alkyl or -R 22 -NR 24 R 25 And;

[0662] R 24 and R 25 Each is independently H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; optionally substituted C3-C 10 Carbocycle; optionally substituted C1-C3 alkylene C3-C 10 Carbocycle; optionally substituted heteroaryl; optionally substituted carbocycle; substituted -C1-C8 alkyl; substituted -C(O)-C1-C8 alkyl; chelating agent; and R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 ; or together -NR 24 R 25 Selected from those forming a C3-C8 heterocycle;

[0663] Each n20 is independently 2 to 26, or

[0664] (e) ~R 20 -R 21 -[-C(R α )HC(O)-N(R N )-] n20 -R 22 -CO2R 26 (XXIV)

[0665] or his stereoisomer or salt, where:

[0666] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0667] R 21 and R 22Each is independently bonded to C1-C3 alkylene, or -C1-C3 alkylene[O-CH2-CH2-] n20 And;

[0668] Each R α is independently H or -R 22 -NR 24 R 25 And;

[0669] Each R N is independently H, C1-C6 alkyl or -R 22 -NR 24 R 25 And;

[0670] R 24 and R 25 Each is independently H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; optionally substituted C3-C 10 Carbocycle; optionally substituted C1-C3 alkylene C3-C 10 Carbocycle; optionally substituted heteroaryl; optionally substituted carbocycle; substituted -C1-C8 alkyl; substituted -C(O)-C1-C8 alkyl; chelating agent; and R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 ; or together -NR 24 R 25 Selected from those forming a C3-C8 heterocycle;

[0671] R 26 is H or C1-C4 alkyl;

[0672] Each n20 is independently 2 to 26, and

[0673] However, at least one R α or R N -R 22 -NR 24 R 25 Im; or

[0674] (f) ~R 20 -R 21 -[C(R α)HC(O)-N(R N )-] n20 -R 22 -N-(R 23 -NR 24 R 25 )2 (XXV)

[0675] or his stereoisomer or salt, where:

[0676] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0677] R 21 and R 22 Each is independently bonded to C1-C3 alkylene, or -C1-C3 alkylene-[O-CH2-CH2-] n20 And;

[0678] Each R α is independently H or -R 22 -NR 24 R 25 And;

[0679] Each R N is independently H or C1-C6 alkyl;

[0680] Each R 23 is independently a C1-C6 alkylene;

[0681] R 24 and R 25 Each is independently H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; optionally substituted C3-C 10 Carbocycle; optionally substituted C1-C3 alkylene C3-C 10 Carbocycle; optionally substituted heteroaryl; optionally substituted carbocycle; substituted -C1-C8 alkyl; substituted -C(O)-C1-C8 alkyl; chelating agent; and R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 ; or together -NR 24 R 25Selected from those forming a C3-C8 heterocycle;

[0682] Each n20 is independently 2 to 26.

[0683] Embodiment 16. In Embodiment 15, R 24 and R 25 Each is independently selected from H and polyhydroxyl groups, except R 24 and R 25 is a linker compound in which both are not H.

[0684] Embodiment 17. A linker compound in Embodiment 15 or 16, wherein the polyhydroxyl group is a linear monosaccharide optionally selected from C6 or C5 sugars, sugar acids, and amino sugars.

[0685] Embodiment 18. In Embodiment 17,

[0686] A C6 or C5 sugar is selected from glucose, ribose, galactose, mannose, arabinose, 2-deoxyglucose, glyceraldehyde, erythrose, threose, xylose, lixose, allose, altrose, goulose, idos, talose, aldose, and ketose;

[0687] The sugar acid is selected from gluconic acid, aldonic acid, uronic acid, and ulosonic acid; or

[0688] A linker compound in which the amino sugar is selected from glucosamine, N-acetylglucosamine, galactosamine, and N-acetylgalactosamine.

[0689] Embodiment 19. In any one of Embodiments 15 to 18, the polar group is selected from the following, or its stereoisomers or salts:

[0690]

[0691]

[0692]

[0693]

[0694]

[0695]

[0696]

[0697]

[0698]

[0699] Here, each R is independently H or alkyl; and each R 39 is independently selected from H, linear monosaccharides, and optionally polyethylene glycols having 1 to 24 ethylene glycol subunits; each n is independently 1 to 12; and the wavy line is site β or site R b Or a linker compound that is attached to an enzyme-cleavable group.

[0700] Embodiment 20. In Embodiment 15 or 16, R 24 and R 25 A linker compound in which one is a linear monosaccharide and the other is a cyclic monosaccharide.

[0701] Embodiment 21. In Embodiment 20, -(NR 24 R 25 ) is selected from the following, or its stereoisomers or salts:

[0702]

[0703] Here, R 11 It is a linker compound that is a cyclic monosaccharide.

[0704] Embodiment 22. In Embodiment 20, the polar group is selected from the following, or its stereoisomers or salts:

[0705]

[0706] Here, R 41 is a cyclic monosaccharide; the wavy line is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[0707] Embodiment 23. In Embodiment 15, R 24 and R 25 A linker compound that is a polyhydroxyl independently selected from cyclic monosaccharides, disaccharides, and polysaccharides.

[0708] Embodiment 24. In Embodiment 23, -(NR 24 R 25 ) is selected from the following, or its stereoisomers or salts:

[0709]

[0710] Here, each R 12 is selected from H and monosaccharides, disaccharides, or polysaccharides; R 5 is a linker compound selected from cyclic monosaccharides, disaccharides, or polysaccharides.

[0711] Embodiment 25. In Embodiment 23, the polar group is selected from the following, or its stereoisomers or salts:

[0712]

[0713] Here, each R 45 is selected from H and monosaccharides, disaccharides, or polysaccharides; R 46 is selected from cyclic monosaccharides, disaccharides, or polysaccharides; and the wavy line is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[0714] Embodiment 26. In Embodiment 15, R 24 and R 25 A linker compound in which is independently selected from a linear monosaccharide and a substituted linear monosaccharide, wherein the substituted linear monosaccharide is substituted with a monosaccharide, a disaccharide, or a polysaccharide.

[0715] Embodiment 27. In Embodiment 26, -(NR 24 R 25 ) is selected from the following, or its stereoisomers or salts:

[0716]

[0717] Here, R 13 is a linear monosaccharide; and each R 14 is a linker compound selected from monosaccharides, disaccharides, and polysaccharides.

[0718] Embodiment 28. In Embodiment 26, the polar group is selected from the following, or its stereoisomers or salts:

[0719]

[0720] Here, R 47 is a linear monosaccharide; and each R 49 is selected from monosaccharides, disaccharides, and polysaccharides; and the wavy line is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[0721] Embodiment 29. In Embodiment 15, R 24 and R 25 A linker compound in which is independently selected from a linear monosaccharide and a substituted monosaccharide, wherein the substituted linear monosaccharide is substituted with one or more substituents selected from carboxyl, ester, and amide, and optionally further substituted with a monosaccharide, disaccharide, or polysaccharide.

[0722] Embodiment 30. In Embodiment 29, -(NR 24 R 25 ) is selected from the following, or its stereoisomers or salts:

[0723]

[0724] Here, each R 15is independently selected from linear monosaccharides and substituted linear monosaccharides; and each R 16 A linker compound independently selected from hydroxyl, carboxyl, ester, and amide.

[0725] Embodiment 31. In Embodiment 29, the polar group is selected from the following, or its stereoisomers or salts:

[0726]

[0727] Here, each R 42 is independently selected from linear monosaccharides and substituted linear monosaccharides; and each R 43 is independently selected from hydroxyl, carboxyl, ester, and amide; the wavy line is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[0728] Embodiment 32. In Embodiment 15, R 24 and R 25 One of them is a -C(O)-polyhydroxyl group or a substituted -C(O)-polyhydroxyl group, and R 24 and R 25 A linker compound in which the other is an H, -C(O)-polyhydroxyl group, a substituted -C(O)-polyhydroxyl group, a polyhydroxyl group, or a substituted polyhydroxyl group; wherein the substituted -C(O)-polyhydroxyl group and the polyhydroxyl group are substituted with a monosaccharide, disaccharide, polysaccharide, carboxyl, ester, or amide.

[0729] Embodiment 33. In Embodiment 32, -(NR 24 R 25 A linker compound selected from the following, or its stereoisomers or salts:

[0730] .

[0731] Embodiment 34. In Embodiment 32, the polar group is selected from the following, or its stereoisomers or salts:

[0732]

[0733] Here, the wavy line is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[0734] Embodiment 35. In Embodiment 15, -(NR 24 R 25 ) is selected from the following, or its stereoisomers or salts:

[0735]

[0736] Here, R 18 A linker compound selected from -C1-C6 alkyls substituted with OH, CH2OH, COOH, or hydroxyl or carboxyl.

[0737] Embodiment 36. In Embodiment 15, R 24 and R 25 is independently H or a substituted -C1-C8 alkyl, and only R 24 and R 25 A linker compound in which neither is H; the substituted -C1-C8 alkyl group is substituted with a hydroxyl and / or carboxyl group.

[0738] Embodiment 37. In Embodiment 36, the polar group is selected from the following, or its stereoisomers or salts:

[0739]

[0740]

[0741] Here, R 48 is selected from H, OH, CH2OH, COOH, or -C1-C6 alkyls substituted with hydroxyl or carboxyl; the wavy line is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[0742] Embodiment 38. In Embodiment 15, -(NR 24 R 25 A linker compound selected from the following, or its stereoisomers or salts:

[0743] .

[0744] Embodiment 39. In Embodiment 15, R 24 and R 25 One of them is H or a substituted -C(O)-C1-C8 alkyl, and R 24 and R 25 A linker compound in which the other one is a substituted -C(O)-C1-C8 alkyl or a substituted -C1-C8 alkyl, wherein the substituted -C(O)-C1-C8 alkyl and the substituted -C1-C8 alkyl are substituted with hydroxyl and / or carboxyl.

[0745] Embodiment 40. In Embodiment 39, the polar group is selected from the following, or its stereoisomers or salts:

[0746]

[0747]

[0748] Here, the wavy line is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[0749] Embodiment 41. In Embodiment 15, R 24 and R 25 α is independently selected from H and a chelating agent, wherein the chelating agent is an alkylene, arylene, carbocyclo, heteroarylene, or heterocarboscyclo-NR 24 R 25 It is arbitrarily attached to the nitrogen of; however, R 24 and R 25 A linker compound in which neither is H.

[0750] Embodiment 42. A linker compound according to Embodiment 41, wherein the chelating agent is selected from ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), benzyl-DTPA, 1,4,7,10-tetraazcyclododecane-N,N',N",N"-tetraacetic acid (DOTA), benzyl-DOTA, 1,4,7-triazcyclononan-N,N',N"-triacetic acid (NOTA), benzyl-NOTA, 1,4,8,11-tetraazcyclotetradecane-1,4,8,11-tetraacetic acid (TETA), and N,N'-dialkyl-substituted piperazine.

[0751] Embodiment 43. In Embodiment 42, the polar group is selected from the following, or its stereoisomers or salts:

[0752]

[0753] Here, the wavy line is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[0754] Embodiment 44. In Embodiment 15, R 24 and R 25 A linker compound in which is independently selected from H, a polyhydroxyl-ether group, and a substituted polyhydroxyl-ether group.

[0755] Embodiment 45. In Embodiment 15, -(NR 24 R 25 A linker compound selected from the following, or its stereoisomers or salts:

[0756] .

[0757] Embodiment 46. A linker compound in any one of Embodiments 13-32, wherein each monosaccharide is independently selected from a C5 or C6 sugar selected from glucose, ribose, galactose, mannose, arabinose, 2-deoxyglucose, glyceraldehyde, erythrose, threose, xylose, lixose, allose, altrose, goulose, idostalose, aldose, and ketose; a sugar acid selected from gluconic acid, aldonic acid, uronic acid, and ulosonic acid; or an amino sugar selected from glucosamine, N-acetylglucosamine, galactosamine, and N-acetylgalactosamine.

[0758] Embodiment 47. A linker compound in any one of Embodiments 1 to 9, wherein the attachment site β is formed from a functional group of a polar precursor compound, said functional group is selected from halo, aldehyde, carboxyl, amino, alkynyl, azido, hydroxyl, carbonyl, carbamate, thiol, urea, thiocarbamate, thiourea, sulfonamide, acylsulfonamide, alkyl sulfonate, triazole, azadibenzocyclooctine, hydrazine, carbonylalkylheteroaryl, and their protected forms.

[0759] Embodiment 48. A linker compound in any one of Embodiments 1 to 14, wherein the polar group has a chemical formula selected from the following:

[0760] (a) ~R 20 -R 21 -[O-CH2-CH2] n20 -R 22 -R 30 (XXX)

[0761] or his stereoisomer or salt, where:

[0762] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0763] R 21 and R 22Each is independently bonded or a C1-C3 alkylene group;

[0764] R 30 is an arbitrarily substituted C3-C 10 Carbocycle; thiourea; optionally substituted thiourea; urea; optionally substituted urea; sulfamide; alkyl sulfamide; acyl sulfamide, optionally substituted alkyl sulfamide; optionally substituted acyl sulfamide; sulfonamide; optionally substituted sulfonamide; guanidine including alkyl and aryl guanidines; phosphoramide; or selected from optionally substituted phosphoramide; or R 30 azido, alkynyl, substituted alkynyl, -NH-C(O)-alkynyl, -NH-C(O)-alkynyl-R 65 ; Cyclooctine; selected from -NH-cyclooctine, -NH-C(O)-cyclooctine, or -NH-(cyclooctine)2; where R 65 is selected from optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocycle, optionally substituted aryl, optionally substituted heterocarbocycle, or optionally substituted heteroaryl;

[0765] n20 is 2 to 26;

[0766] (b) ~R 20 -R 21 -[O-CH2-CH2] n20 -R 22 -NH-C(O)-R 31 (XXXI)

[0767] or his stereoisomer or salt, where:

[0768] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0769] R 21 and R 22 Each is independently bonded or a C1-C3 alkylene group;

[0770] R 31is a branched polyethylene glycol chain, each branch has 1 to 26 ethylene glycol subunits, and each branch has R at its end 35 having;

[0771] R 35 is Azido, Alkynyl, Alkynyl-R 65 , cyclooctine or cyclooctine-R 65 and, here R 65 is selected from optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocycle, optionally substituted aryl, optionally substituted heterocarbocycle, or optionally substituted heteroaryl;

[0772] n20 is 2 to 26;

[0773] (c) ~R 20 -R 21 -[O-CH2-CH2] n20 -R 22 -C(O)NH-R 31 (XXXII)

[0774] or his stereoisomer or salt, where:

[0775] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0776] R 21 and R 22 Each is independently bonded or a C1-C3 alkylene group;

[0777] R 31 is a branched polyethylene glycol chain, each branch independently has 1 to 26 ethylene glycol subunits, and each branch has R at its end 35 having;

[0778] R 35 is Azido, Alkynyl, Alkynyl-R 65 , cyclooctine or cyclooctine-R 65 and, here R 65is selected from optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocycle, optionally substituted aryl, optionally substituted heterocarbocycle, and optionally substituted heteroaryl;

[0779] n20 is 2 to 26;

[0780] (d) ~R 20 -R 21 -[O-CH2-CH2] n20 -R 22 -C(O)NR 31 -R 22 -NR 24 R 25 (XXXIII)

[0781] or his stereoisomer or salt, where:

[0782] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0783] R 31 is H or R 22 -NR 24 R 25 And;

[0784] R 21 and R 22 Each is independently bonded or a C1-C3 alkylene group;

[0785] R 24 and R 25 Each is independently selected from H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group, provided that R 24 and R 25 Neither is H;

[0786] n20 is 2 to 26;

[0787] (e) ~R 20 -R 21 -[O-CH2-CH2] n20 -R 22 -N(R 33 -R 31)2(XXXIV)

[0788] or his stereoisomer or salt, where:

[0789] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0790] R 21 and R 22 Each is independently bonded or a C1-C3 alkylene group;

[0791] R 31 is a branched polyethylene glycol chain, each branch has 1 to 26 ethylene glycol subunits, and each branch has R at its end 35 having;

[0792] R 33 is C1-C3alkylene, C1-C3alkylene-C(O), -C(O)-C1-C3alkylene or -C(O)-C1-C3alkylene-C(O);

[0793] R 35 is Azido, Alkynyl, Alkynyl-R 65 , cyclooctine or cyclooctine-R 65 and, here R 65 is selected from optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocycle, optionally substituted aryl, optionally substituted heterocarbocycle, or optionally substituted heteroaryl;

[0794] n20 is 2 to 26;

[0795] (f) ~R 20 -(R 21 -[CH2-CH(OR 34 )-CH2-O] n20 -R 36 ) n25 (XXXV)

[0796] or his stereoisomer or salt, where:

[0797] R 20 It is site β or site Rb or an attachment group to an enzyme-cleavable group;

[0798] Each R 21 is independently bonded, -O- or C1-C3 alkylene group;

[0799] Each R 34 is independently H, -[CH2-CH(OH)-CH2-O] n20 -R 36 , -C(O)-NR 24 R 25 or -C(O)N(R N )-C1-C6alkylene-NR 24 R 25 And;

[0800] R N is H or C1-C4 alkyl;

[0801] R 24 and R 25 Each is independently selected from H; a polyhydroxyl group; or a substituted polyhydroxyl group, provided that R 24 and R 25 Both are not H;

[0802] Each R 36 is independently H, C1-C6alkylene-C(OH)H-NR 44 R 45 , C1-C6alkylene-C(OH)H-C1-C6alkylene-NR 44 R 45 , -C(O)-NR 24 R 25 , -C(O)N(R N )-C1-C6alkylene-NR 24 R 25 , C1-C6alkylene-C(O)NR 24 R 25 or C1-C6 alkylene-CO2R 37 And;

[0803] Each R 37 is independently H or C1-C6 alkyl;

[0804] R 44 and R 45Each is independently selected from H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; and R 44 and R 45 Both are not H;

[0805] Each n20 is independently 1 to 26;

[0806] n25 is 1 or 2;

[0807] (g) ~R 20 -R 21 -[[CH2-CH2-O] n20 -R 22 -[CH2-[CH(OH)] n23 -CH2-O] n21 ] n22 -R 23 -NR 24 -R 25 (XXXVI)

[0808] or his stereoisomer or salt, where:

[0809] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0810] R 21 , R 22 and R 23 Each is independently bonded to a C1-C3 alkylene group;

[0811] R 24 and R 25 Each is independently selected from H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group, provided that R 24 and R 25 Neither is H;

[0812] Each n20 is independently 0 to 26, and each n21 is independently 0 to 26, provided that at least one of n20 or n21 is 2 to 26;

[0813] n22 is 1 to 5;

[0814] Each n23 is independently 1 or 2;

[0815] (h) ~R 20 -(R 21 -[O-CH2-CH2] n20 -R 22 -N(R N )-CO2-[CH2-CH(OR 34 )-CH2-O] n21 -R 36 ) n25

[0816] (XXXVII)

[0817] or his stereoisomer or salt, where:

[0818] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0819] R 21 and R 22 Each is independently bonded or a C1-C3 alkylene group;

[0820] R N is H or C1-C4 alkyl;

[0821] R 24 and R 25 Each is independently selected from H; a polyhydroxyl group; or a substituted polyhydroxyl group, provided that R 24 and R 25 Both are not H;

[0822] Each R 34 is independently H, -[CH2-CH(OH)-CH2-O] n20 -R 36 or -C(O)N(R N )-C1-C6alkylene-NR 24 R 25 And;

[0823] Each R 36 is independently H, C1-C6alkylene-C(OH)H-NR 44 R45 , C1-C6alkylene-C(OH)H-C1-C6alkylene-NR 44 R 45 , -C(O)N(R N )-C1-C6alkylene-NR 24 R 25 , C1-C6alkylene-C(O)NR 24 R 25 or C1-C6 alkylene-CO2R 37 And;

[0824] Each R 37 is independently H or C1-C6 alkyl;

[0825] R 44 and R 45 Each is independently selected from H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; and R 44 and R 45 Both are not H;

[0826] n20 is 2 to 26;

[0827] n21 is 1 to 26;

[0828] n25 is 1 or 2;

[0829] (i) ~R 20 -(R 21 -[N(R N )-C(O)-[O-CH2-CH(OH)-CH2] n20 ] n21 -R 22 -NR 24 R 25 ) n25

[0830] (XXXVIII)

[0831] or his stereoisomer or salt, where:

[0832] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0833] R 21 and R 22Each is independently bonded or a C1-C3 alkylene group;

[0834] R N is H or C1-C4 alkyl;

[0835] R 24 and R 25 Each is independently selected from H; a polyhydroxyl group; or a substituted polyhydroxyl group, provided that R 24 and R 25 Neither is H;

[0836] n20 is 2 to 26;

[0837] n21 is 1 to 4;

[0838] n25 is 1, 2, or 3;

[0839] (j) ~R 20 -(R 21 -[C(R α )HC(O)-N(R N )] n20 -R 22 -[CH2-CH2-O] n20 -NR 24 R 25 ) n25

[0840] (XXXIX)

[0841] or his stereoisomer or salt, where:

[0842] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0843] R 21 and R 22 are independently bonded, C1-C3 alkylene, -C1-C3 alkylene-[O-CH2-CH2-] n20 , -[CH2-CH2-O] n20 -C1-C3alkylene- or -C1-C3alkylene-[O-CH2-CH2-] n20 -C(O)- and;

[0844] Each R α is independently H or -R22 -NR 24 R 25 And;

[0845] Each R N is independently H, C1-C6 alkyl or -R 22 -NR 24 R 25 And;

[0846] R 24 and R 25 Each is independently H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; optionally substituted C3-C 10 Carbocycle; optionally substituted C1-C3 alkylene C3-C 10 Carbocycle; optionally substituted heteroaryl; optionally substituted carbocycle; substituted -C1-C8 alkyl; substituted -C(O)-C1-C8 alkyl; chelating agent; R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 ; or together -NR 24 R 25 Selected from those forming a C3-C8 heterocycle, provided that R 24 and R 25 Neither is H;

[0847] Each n20 is independently 0 to 26, provided that at least one n20 is 2 to 26;

[0848] n25 is 1 or 2; or

[0849] (k)

[0850]

[0851] or his stereoisomer or salt, where:

[0852] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0853] R 21 , R 22 and R23 Each is independently bonded, C1-C3 alkylene, -C1-C3 alkylene-[O-CH2-CH2-] n20 , -[CH2-CH2-O] n20 -C1-C3alkylene- or -C1-C3alkylene-[O-CH2-CH2-] n20 -C(O)- and;

[0854] Each R α is independently H or -R 22 -NR 24 R 25 And;

[0855] Each R N is independently H, C1-C6 alkyl or -R 22 -NR 24 R 25 And;

[0856] R 24 and R 25 Each is independently H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; optionally substituted C3-C 10 Carbocycle; optionally substituted C1-C3 alkylene C3-C 10 Carbocycle; optionally substituted heteroaryl; optionally substituted carbocycle; substituted -C1-C8 alkyl; substituted -C(O)-C1-C8 alkyl; chelating agent; R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 ; or together -NR 24 R 25 Selected from those forming a C3-C8 heterocycle, provided that R 24 and R 25 Neither is H;

[0857] R 26 is H or C1-C6 alkyl;

[0858] Each n20 is independently 0 to 26, provided that at least one n20 is 2 to 26;

[0859] Each n21 is independently 0 to 26, provided that at least one n21 is 2 to 26.

[0860] Embodiment 49. In any one of Embodiments 1 to 14, the polar group has a chemical formula selected from the following, or a stereoisomer thereof, or a salt:

[0861] ~R 20 -R 21 -[O-CH2-CH2] n20 -R 22 -NH-C(O)-R 31 (XXXI),

[0862] ~R 20 -R 21 -[O-CH2-CH2] n20 -R 22 -C(O)NH-R 31 (XXXII), and

[0863] ~R 20 -R 21 -[O-CH2-CH2] n20 -R 22 -N-(R 33 -R 31 )2(XXXIII);

[0864] Here:

[0865] R 20 It is site β or site R b or an attachment group to an enzyme-cleavable group;

[0866] R 21 and R 22 Each is independently bonded or a C1-C3 alkylene group;

[0867] R 31 is a branched polyethylene glycol chain, each branch has 1 to 26 ethylene glycol subunits, and each branch has R at its end 35 having;

[0868] R 33 is C1-C3alkylene, -C1-C3alkylene-C(O), -C(O)-C1-C3alkylene or -C(O)-C1-C3alkylene-C(O);

[0869] R 35 is Azido, Alkynyl, Alkynyl-R 65 , cyclooctine or cyclooctine-R 65 and, here R 65 is selected from optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocycle, optionally substituted aryl, optionally substituted heterocarbocycle, or optionally substituted heteroaryl; and the wavy (~) line is R 20 Indicates the attachment site for; n20 is a linker compound of 2 to 26.

[0870] Embodiment 50. In Embodiment 48 or 49, the polar group is formed from a precursor group selected from the following:

[0871]

[0872] Here, R 65 is selected from optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocycle, optionally substituted aryl, optionally substituted heterocarbocycle, or optionally substituted heteroaryl; and the wavy line is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[0873] Embodiment 51. In Embodiment 48 or 49, part □ part R b or a linker compound in which attachment to an enzyme-cleavable group is formed from a functional group of a precursor compound of a polar group, said functional group being selected from halo, aldehyde, carboxyl, amino, alkynyl, azido, hydroxyl, carbonyl, carbamate, thiol, urea, thiocarbamate, thiourea, sulfonamide, acylsulfonamide, alkyl sulfonate, triazole, azadibenzocyclooctine, hydrazine, carbonylalkylheteroaryl, and their protected forms.

[0874] Embodiment 52. In any one of Embodiments 1-14, the polar group has the following chemical formula:

[0875] ~R 20 -(R 43 -R 41 -[O-CH2-CH2] n40 -R 42 -R 43 -(NR 44 R 45 ) n41 ) n42 (XL)

[0876] or having its stereoisomer or salt, where:

[0877] R 20 Silver area □, area R b or an attachment group to an enzyme-cleavable group;

[0878] R 41 and R 42 Each is independently bonded to a C1-C6 alkylene;

[0879] Each R 43 are independently bonded, or C1-C 12 Alkylene, -NH-C1-C 12 Alkylene, -C1-C 12 Alkylene-NH-, -C(O)-C1-C 12 Alkylene, -C1-C 12 Alkylene-C(O)-, -NH-C1-C 12 Alkylene-C(O)-, -C(O)-C1-C 12 Alkylene-NH-, -NH-C(O)-NH-, -NH-C(O)-, -NH-C(O)-C1-C 12 Alkylene, -C(O)-NH-C1-C 12 Alkylene, -heteroarylene, heteroaryl-C1-C 12 Alkylene, heteroaryl-C1-C 12 Alkylene-C(O)-, or -C(O)NR 46 R 47 Selected from, where R 46 and R 47 One of them is H or C1-C 12It is an alkylene and the other is C1-C 12 It is an alkylene;

[0880] R 44 and R 45 Each is independently H, a polyhydroxyl group, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, or a substituted -C(O)-polyhydroxyl group, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates; n40 is 2 to 26;

[0881] n41 is 1 to 6;

[0882] n42 is a linker compound with 1 to 6.

[0883] Embodiment 53. In any one of Embodiments 1-14, the polar group has the following chemical formula:

[0884] ~R 20 -(R 41 -[O-CH2-CH2] n40 -R 42 -R 43 -(NR 44 R 45 ) n41 ) n42 (XLI)

[0885] or having its stereoisomer or salt, where:

[0886] R 20 Silver area □, area R b or an attachment group to an enzyme-cleavable group;

[0887] R 41 and R 42 Each is independently bonded to a C1-C6 alkylene;

[0888] R 43 It is a bond, or C1-C 12 Alkylene, -NH-C1-C 12 Alkylene, -C1-C 12 Alkylene-NH-, -C(O)-C1-C 12 Alkylene, -C1-C 12 Alkylene-C(O)-, -NH-C1-C12 Alkylene-C(O)-, -C(O)-C1-C 12 Alkylene-NH-, -NH-C(O)-NH-, -NH-C(O)-, -NH-C(O)-C1-C 12 Alkylene, C(O)-NH-C1-C 12 Alkylene, -heteroarylene, heteroaryl-C1-C 12 Alkylene, heteroaryl-C1-C 12 Alkylene-C(O)-, or -C(O)NR 46 R 47 Selected from, where R 46 and R 47 One of them is H or C1-C 12 It is an alkylene and the other is C1-C 12 It is an alkylene;

[0889] R 44 and R 45 Each is independently H, a polyhydroxyl group, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, or a substituted -C(O)-polyhydroxyl group, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates; n40 is 1 to 26;

[0890] n41 is 1 to 6;

[0891] n42 is a linker compound with 1 to 6.

[0892] Embodiment 54. In any one of Embodiments 1-14, the polar group has the following chemical formula:

[0893] ~R 20 -(R 41 -[O-CH2-CH2] n40 -R 42 -R 43 -(NR 44 R 45 ) n41 ) n42 (XLII)

[0894] or having its stereoisomer or salt, where:

[0895] R 20Silver area □, area R b or an attachment group to an enzyme-cleavable group;

[0896] R 41 and R 42 Each is independently bonded to a C1-C3 alkylene;

[0897] R 43 It is a bond, or C1-C6 alkylene, -NH-C1-C 12 Alkylene, -C1-C6alkylene-NH-, -C(O)-C1-C6alkylene, -C1-C6alkylene-C(O)-, -NH-C1-C6alkylene-C(O)-, -C(O)-C1-C6alkylene-NH-, -NH-C(O)-NH-, -NH-C(O)-, -NH-C(O)-C1-C6alkylene, -C(O)-NH-C1-C 12 Alkylene, -heteroarylene, heteroaryl-C1-C6alkylene, heteroaryl-C1-C6alkylene-C(O)-, or -C(O)NR 46 R 47 Selected from, where R 46 and R 47 One is H or C1-C6 alkylene and the other is C1-C 12 It is an alkylene;

[0898] R 44 and R 45 Each is independently H, a polyhydroxyl group, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, or a substituted -C(O)-polyhydroxyl group, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates; n40 is 1 to 16;

[0899] n41 is 1 to 4;

[0900] n42 is a linker compound with 1 to 4.

[0901] Embodiment 55. In any one of embodiments 15, 48, 49, and 52-54, R 20A linker compound formed from a functional group of a precursor compound of this polar group, wherein the functional group is selected from halo, aldehyde, carboxyl, amino, alkynyl, azido, hydroxyl, carbonyl, carbamate, thiol, urea, thiocarbamate, thiourea, sulfonamide, acylsulfonamide, alkyl sulfonate, triazole, azadibenzocyclooctine, hydrazine, carbonylalkylheteroaryl, or its protected form.

[0902] Embodiment 56. In any one of embodiments 15, 48, 19, and 52-54, R 20 One of the following structures:

[0903]

[0904]

[0905] or includes its stereoisomer, wherein R is H, C1-C6 alkyl or polyhydroxyl group, and n is 0 to 12, and ( ) is site β or site R b or indicates attachment to an enzyme-cleavable group, ( A linker compound in which ) represents the attachment site for the remaining portion of the polar group.

[0906] Embodiment 57. In any one of embodiments 15, 48, 19, and 52-54, R 20 One of the following structures:

[0907]

[0908]

[0909] or having its stereoisomer, where n = 0 to 12, and ( ) is site β or site R b or indicates attachment to an enzyme-cleavable group, ( A compound in which ) represents the attachment site for the remaining part of the polar group.

[0910] Embodiment 58. In any one of Embodiments 52-57, R 43 -(NR 44 R 45 ) n41 One of the following structures:

[0911]

[0912] or having its stereoisomer, where R = H, C1-C6 alkyl, polyhydroxyl group, or substituted polyhydroxyl group; ( ) is R for the remainder of the polar group 43 A linker compound that indicates the attachment site.

[0913] Embodiment 59. In any one of embodiments 52-57, R 43 -(NR 44 R 45 ) n41 One of the following structures:

[0914]

[0915] or having his stereoisomer, here ( ) is R for the remainder of the polar group 43 A linker compound that indicates the attachment site.

[0916] Embodiment 60. In any one of Embodiments 52-59, -NR 44 R 45 One of the following structures:

[0917]

[0918]

[0919] or having his stereoisomer, here ( ) is -NR for the remainder of the polar group 44 R 45 A linker compound that indicates the attachment site.

[0920] Embodiment 61. In any one of Embodiments 1-60, the polarity giga has one of the following structures before attachment to the linker unit:

[0921]

[0922]

[0923]

[0924]

[0925]

[0926]

[0927]

[0928]

[0929]

[0930]

[0931]

[0932]

[0933]

[0934]

[0935]

[0936]

[0937]

[0938]

[0939]

[0940]

[0941]

[0942]

[0943]

[0944]

[0945]

[0946] Here:

[0947] (*) indicates site β or site R b or indicates attachment to an enzyme-cleavable group;

[0948] Each R is independently H or C1-C6 alkyl;

[0949] R' is H, C1-C6 alkyl, -N(R 24 )(R 25 ) or -CO2H and;

[0950] Each n is independently 1 to 12;

[0951] X is O, NR, or -CH2- and;

[0952] V is a bond or C1-C6 alkyl;

[0953] R 24 and R 25 One of them is H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; substituted -C(O)-C1-C8 alkyl; chelating agent; and R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 Selected from; R 24 and R 25 The other one is H; polyhydroxyl group; substituted polyhydroxyl group; -C(O)-polyhydroxyl group; substituted -C(O)-polyhydroxyl group; substituted -C(O)-C1-C8 alkyl; chelating agent; R 28 -C(O)-R, the sugar unit of this chemical formula (XII) or (XIII). 28 ; and optionally selected from polyethylene glycol having 1 to 24 ethylene glycol subunits, wherein R 24 and R 25 is a linker compound in which both are not H.

[0954] Embodiment 62. A linker compound in which, in any one of Embodiments 1-14, the polar group has a chemical formula selected from the following:

[0955] (a) ~R 40 -(R 43 -R 41 -[O-CH2-CH2] n40 -R 46 -[O-CH2-CH2] n40 -R 42 -R 43 -(NR 44 R 45 ) n41 ) n42

[0956] (XLIII)

[0957] or his stereoisomer or salt, where:

[0958] R 40 silver part R b or an attachment group to an enzyme-cleavable group;

[0959] R 41 and R 42 Each is independently bonded to a C1-C6 alkylene;

[0960] Each R 43 They combine independently, C1-C 12 Alkylene, -OC1-C 12 Alkylene, -C(=O)-, -NH-C1-C 12 Alkylene, -C1-C 12 Alkylene-NH-, -C(O)-C1-C 12 Alkylene, -C1-C 12 Alkylene-C(O)-, -NH-C1-C 12 Alkylene-C(O)-, -C(O)-C1-C 12 Alkylene-NH-, -NH-C(O)-NH-, -NH-C(O)-, -NH-C(O)-C1-C 12 Alkylene, -C(O)-NH-C1-C 12 Alkylene, C1-C 12 Alkylene-NH-C(O)-, -heteroarylene, heteroaryl-C1-C 12 Alkylene, heteroaryl-C1-C12 Alkylene-C(O)-, or -C(O)NR 46 R 47 Selected from, where R 46 and R 47 One of them is H or C1-C 12 It is an alkylene and the other is C1-C 12 It is an alkylene;

[0961] R 44 and R 45 is each independently H, a polyhydroxyl group, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, or a substituted -C(O)-polyhydroxyl group, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, provided that R 44 and R 45 Both are not H;

[0962] Each R 46 is independently -NR 50 -, -NR 50 -C1-C6alkylene-NR 50 -, -NR 50 -C(O)-NR 50 -S(O)2-NR 50 - or -NR 50 Selected from -C(O)-C1-6alkylene-;

[0963] Each R 50 is independently selected from H, C1-C6 alkyl, or polyhydroxyl groups;

[0964] Each n40 is independently 2 to 26;

[0965] n41 is 1 to 6;

[0966] n42 is 1 to 6;

[0967] (b) ~R 40 -(R 51 -[O-CH2-CH2] n43 -R 52 -X1-R 55 -X2-R 53 -[O-CH2-CH2] n43 -R54 -[X3-R 56 ] n44 -R 57 ) n45

[0968] (XLIV)

[0969] or his stereoisomer or salt, where:

[0970] R 40 silver part R b or an attachment group to an enzyme-cleavable group;

[0971] R 51 , R 52 , R 53 and R 54 Each is independently bonded to a C1-C6 alkylene;

[0972] X1, X2, and X3 are each independently -NR N -C(O)- or -C(O)-NR N - and;

[0973] Each R N represents an H, C1-C6 alkyl, or polyhydroxyl group independently;

[0974] R 55 and R 56 Each independently represents a divalent polyhydroxyl group;

[0975] R 57 is H, OH, or C1-C6 alkyl;

[0976] Each n43 is independently 0 to 26, provided that at least one n43 is 1 to 26;

[0977] n44 is 0 to 10;

[0978] n45 is 1 or 2; or

[0979] (c) ~R 40 -R 51 -[O-CH2-CH2] n43 -R 52 -N-(R 53 -X1-R 54 -[O-CH2-CH2] n43-(NR 44 R 45 ))2

[0980] (XLV)

[0981] or his stereoisomer or salt, where:

[0982] R 40 silver part R b or an attachment group to an enzyme-cleavable group;

[0983] R 51 , R 53 and R 54 Each is independently bonded or optionally substituted C1-C6 alkylene;

[0984] R 52 is a bond, C1-C6 alkylene, -C(O)- or -OC(O)- and;

[0985] Each X1 is independently -NR N -C(O)- or -C(O)-NR N - and;

[0986] Each R N represents an H, C1-C6 alkyl, or polyhydroxyl group independently;

[0987] R 44 and R 45 is each independently H, a polyhydroxyl group, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, or a substituted -C(O)-polyhydroxyl group, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, provided that R 44 and R 45 Both are not H;

[0988] Each n43 is independently 2 to 26.

[0989] Embodiment 63. In Embodiment 52, the polar group has one of the following structures before attachment to the enzyme-cleavable group and / or linker unit:

[0990]

[0991]

[0992] Here:

[0993] (*) is part R b or representing an attachment site for an enzyme-cleavable group;

[0994] Each R is independently H, alkyl, or polyhydroxyl group;

[0995] R 44 and R 45 is each independently H, a polyhydroxyl group, a substituted polyhydroxyl group, a -C(O)-polyhydroxyl group, or a substituted -C(O)-polyhydroxyl group, wherein the optional substituent is selected from sulfates, phosphates, alkyl sulfates, and alkyl phosphates, provided that R 44 and R 45 Both are not H;

[0996] Each n is a linker compound in which n is independently 1 to 12.

[0997] Embodiment 64. In any one of Embodiments 1-14, the polar group is a chemical formula selected from the following:

[0998]

[0999] or having its stereoisomer or salt, where:

[1000] Each Y is independently R 76 or And;

[1001] Each R 76 It independently consists of H, acetyl, -P(=O)(OH)2, or -(CH2) v -OS(=O)2(OH) and;

[1002] Each R a and R b is independently H, or R a and R b They form an iodine group together with the carbon to which they are attached;

[1003] Each q is independently 2-26 and;

[1004] Each m is independently 1 to 4;

[1005] Each n is independently 1 to 4;

[1006] Each v is independently 1 to 6;

[1007] Each * is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[1008] Embodiment 65. In any one of Embodiments 1-14, the polar group is a chemical formula selected from the following:

[1009]

[1010] or having its stereoisomer or salt, where:

[1011] Each R 76 It independently consists of H, acetyl, -P(=O)(OH)2, or -(CH2) v S(=O)2(OH) and;

[1012] Each q is independently 2-26 and;

[1013] Each m is independently 1 to 4;

[1014] Each n is independently 1 to 4;

[1015] Each v is independently 1 to 6;

[1016] Each * is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[1017] Embodiment 66. In any one of Embodiments 1-14, the polar group is a chemical formula selected from the following:

[1018] ;

[1019] or having its stereoisomer or salt, where:

[1020] Each q is independently 2-26 and;

[1021] Each m is independently 1 to 4;

[1022] Each n is independently 1 to 4;

[1023] Each * is R b Or a linker compound that is an attachment site for an enzyme-cleavable group.

[1024] Embodiment 67. In Embodiment 66, Y is R 76 In linker compound.

[1025] Embodiment 68. In Embodiment 66, Y In linker compound.

[1026] Embodiment 69. In Embodiment 66, each R a and R b A linker compound in which is independently H.

[1027] Embodiment 70. In Embodiment 66, R a and R b A linker compound that forms an oxo group together with the carbon to which they are attached.

[1028] Embodiment 71. A linker compound in which q is 10-20, in any one of Embodiments 64-66.

[1029] Embodiment 72. A linker compound in which q is 12, in any one of Embodiments 64-66.

[1030] Embodiment 73. In any one of Embodiments 1-72, one of the following structures before the polar group attaches to the amino acid unit:

[1031]

[1032]

[1033]

[1034] ;

[1035] or having its stereoisomer, where R a is H or C 1-6 A linker compound that is alkyl and n is 1-20.

[1036] Embodiment 74. In any one of Embodiments 1-73, one of the following structures before the polar group attaches to the amino acid unit:

[1037]

[1038]

[1039]

[1040]

[1041]

[1042] ,

[1043] or having its stereoisomer, where R a is H or C 1-6 A linker compound that is alkyl and n is 1-20.

[1044] Embodiment 75. In any one of Embodiments 1-74, one of the following structures before the polar group attaches to the amino acid unit:

[1045]

[1046]

[1047]

[1048]

[1049]

[1050] ,

[1051] or having its stereoisomer, where R a is H or C 1-6 A linker compound that is alkyl and n is 1-20.

[1052] Embodiment 76. In any one of Embodiments 1-75, the polar group is selected from the following, or its stereoisomers or salts:

[1053]

[1054]

[1055]

[1056]

[1057]

[1058]

[1059]

[1060]

[1061]

[1062]

[1063]

[1064]

[1065]

[1066]

[1067]

[1068]

[1069]

[1070]

[1071]

[1072]

[1073]

[1074]

[1075]

[1076]

[1077]

[1078]

[1079]

[1080]

[1081]

[1082] Here, each Z is attached from *, which is individually selected from the following:

[1083] ;

[1084] Here, each is site β or site R b Or a linker compound that is attached to an enzyme-cleavable group.

[1085] Embodiment 77. In any one of Embodiments 1 to 75, the polar group is as follows:

[1086]

[1087]

[1088]

[1089]

[1090]

[1091] ,

[1092] or is selected from its stereoisomers, wherein each is a linker compound that represents the attachment site of an amino acid unit.

[1093] Embodiment 78. In any one of Embodiments 1 to 77, the polar group has the following chemical formula:

[1094]

[1095] A linker compound comprising at least one carboxyl unit having its stereoisomer or salt:

[1096] Here

[1097] (a)

[1098] L 70 is selected from C1-C8alkylene, C1-C8alkylene-C(O)-, -C(O)-C1-C8alkylene-, and -C(O)-C1-C8alkylene-C(O)-, and * is R b , an enzyme-cleavable group, or an attachment site for the remainder of the polar group;

[1099] R 70 is ~NR 71 (R 72 -R 73 ) and, here R 71 H, C1-C 12 Alkyl, substituted C1-C 12 Selected from alkyl, or polyethylene glycol (optionally having 1 to 12 ethylene glycol subunits), and R 72 is a bond or is selected from optionally substituted C1-C3 alkylene, optionally substituted ether, optionally substituted thioether, optionally substituted ketone, optionally substituted amide, polyethylene glycol (optionally having 1 to 12 ethylene glycol subunits), optionally substituted carbocycle, optionally substituted aryl, or optionally substituted heteroaryl, and R 73 ... is a carboxyl or polycarboxyl, wherein the polycarboxyl comprises 1 to 10, or 1 to 6, or 1 to 4 carboxyl groups, wherein the carboxyl groups are interconnected by alkyl, alkylene, substituted alkyl, substituted alkylene, heteroalkyl, heteroalkylene, amino and / or amide; or

[1100] (b)

[1101] L 70is selected from C1-C8alkylene, C1-C8alkylene-C(O)-, -C(O)-C1-C8alkylene-, and -C(O)-C1-C8alkylene-C(O)-, and * is R b , an enzyme-cleavable group, or an attachment site for the remainder of the polar group;

[1102] R 70 is ~NR 71 (R 75 - (R 73 )2) and, here R 71 H, C1-C 12 Alkyl, substituted C1-C 12 Selected from alkyl, or polyethylene glycol (optionally having 1 to 12 ethylene glycol subunits), and R 75 is a branched optionally substituted C1-C3 alkylene, optionally substituted ether, optionally substituted thioether, optionally substituted ketone, optionally substituted amide, polyethylene glycol (optionally having 1 to 12 ethylene glycol subunits), optionally substituted carbocycle, optionally substituted aryl, or optionally substituted heteroaryl, and each R 73 is independently a carboxyl or polycarboxyl, wherein the polycarboxyl comprises 1 to 10, or 1 to 6, or 1 to 4 carboxyl groups, wherein the carboxyl groups are interconnected by alkyl, alkylene, substituted alkyl, substituted alkylene, heteroalkyl, heteroalkylene, amino and / or amide; or

[1103] (c)

[1104] L 70 is selected from C1-C8alkylene, C1-C8alkylene-C(O)-, -C(O)-C1-C8alkylene-, and -C(O)-C1-C8alkylene-C(O)-, and * is R b , an enzyme-cleavable group, or an attachment site for the remainder of the polar group;

[1105] R 70 is ~N(R 74 -R73 )(R 72 - R 73 ) and, here R 72 and R 74 Each is independently selected from optionally substituted C1-C3 alkylenes, optionally substituted ethers, optionally substituted thioethers, optionally substituted ketones, optionally substituted amides, polyethylene glycol (optionally having 1 to 12 ethylene glycol subunits), optionally substituted carbocycles, optionally substituted aryls, or optionally substituted heteroaryls, and each R 73 is independently a carboxyl or polycarboxyl, wherein the polycarboxyl comprises 1 to 10, or 1 to 6, or 1 to 4 carboxyl groups, wherein the carboxyl groups are interconnected by alkyl, alkylene, substituted alkyl, substituted alkylene, heteroalkyl, heteroalkylene, amino and / or amide.

[1106] Embodiment 79. A linker compound in any one of Embodiments 1 to 78, wherein the polar group comprises a polymer unit and a sugar unit.

[1107] Embodiment 80. A linker compound in any one of Embodiments 1 to 78, wherein the polar group comprises at least two polymer units.

[1108] Embodiment 81. A linker compound in any one of Embodiments 1 to 78, wherein the polar group comprises a polymer unit and a carboxyl unit.

[1109] Embodiment 82. A linker compound comprising at least two polar groups in any one of Embodiments 1 to 78.

[1110] Embodiment 83. A linker compound in any one of Embodiments 1 to 78, wherein the polar group comprises a polymer unit, a sugar unit, and a carboxyl unit.

[1111] Embodiment 84. A linker compound in any one of Embodiments 1 to 78, wherein the polar group comprises at least two polymer units, at least one sugar unit, and at least one carboxyl unit.

[1112] Embodiment 85. A linker compound in any one of Embodiments 9 to 78, wherein the enzyme-cleavable group comprises at least two amino acids.

[1113] Embodiment 86. A linker compound comprising at least one polar group attached to an enzyme-cleavable group in any one of Embodiments 9 to 85.

[1114] Embodiment 87. In any one of Embodiments 1-86, having one of the following structures:

[1115]

[1116]

[1117]

[1118]

[1119] ,

[1120] Here

[1121] R c is a bond or C1-6 alkylene;

[1122] The wavy line on the amino group indicates the attachment site to the stretcher group, or indicates H prior to attachment to the stretcher group;

[1123] β- is an attachment site for at least one polar group;

[1124] A linker compound in which the benzylic H on the benzylic OH is optionally replaced by bonding to at least one of the drug units or to a linker attached to at least one of the drug units.

[1125] Embodiment 88. In any one of Embodiments 1-86, one of the following structures:

[1126]

[1127]

[1128]

[1129] A linker compound comprising or its stereoisomers, wherein the polar group is attached to an amino acid subunit of an amino acid unit, and the hydroxyl of the para-aminobenzyl group or the H of the amino group or the H of the hydroxyl of the glycine residue of the GGFG peptide is optionally replaced by a bond to at least one of the drug units or to a linker attached to at least one of the drug units, and the wavy line on the amino group indicates a stretcher group or an attachment site to the amino acid unit or indicates H prior to attachment.

[1130] Embodiment 89. Any one of Embodiments 1-88, comprising a chemical formula selected from the following:

[1131]

[1132] Here, square brackets represent amino acid units, each aa is an arbitrary subunit of the amino acid unit, L2 is a linker unit, and each wavy line (~) represents an attachment site for a stretcher group; aa1(POLY) is a polymer unit attached to the amino acid subunit of the amino acid unit, SU is a sugar unit attached to the subunit or linker unit of the amino acid unit, CU is a carboxyl unit attached to the subunit or linker unit of the amino acid unit; double wavy ( The line indicates an attachment site for at least one of the drug units, wherein aa and aa1 are linker compounds independently selected from alpha, beta, and gamma amino acids and their derivatives.

[1133] Embodiment 90. Any one of Embodiments 1-88, comprising a chemical formula selected from the following:

[1134]

[1135] Here, square brackets represent amino acid units, each aa is an amino acid subunit of the amino acid unit, L2 is a linker subunit attached to the side chain of aa, and the wavy line (~) indicates the attachment site for the stretcher group; aa1(POLY) is a polymer unit attached to aa, SU is a sugar unit attached to aa, CU is a carboxyl unit attached to aa, and double wavy ( The line indicates an attachment site for at least one of the drug units; where aa and aa1 are linker compounds independently selected from alpha, beta, and gamma amino acids and their derivatives.

[1136] Embodiment 91. Any one of Embodiments 1-88, comprising a chemical formula selected from the following:

[1137]

[1138] Here, square brackets represent amino acid units, aa is an arbitrary subunit of the amino acid unit, L2 is a linker unit, and the wavy line (~) represents an attachment site for a stretcher group; each aa1(POLY) and aa2(POLY) is a polymer unit attached to aa or another polymer unit; each SU is a sugar unit attached to aa or another sugar unit, each CU is a carboxyl unit attached to aa or another carboxyl unit, and double wavy ( The line indicates an attachment site for at least one of the drug units; where aa, aa1, and aa2 are linker compounds independently selected from alpha, beta, and gamma amino acids and their derivatives.

[1139] Embodiment 92. Any one of Embodiments 1-88, comprising a chemical formula selected from the following:

[1140]

[1141] Here, square brackets represent amino acid units, aa is an amino acid subunit of the amino acid unit, L2 is a linker unit attached to the side chain of aa, and each wavy line (~) indicates an attachment site for a stretcher group; each aa1(POLY) and aa2(POLY) is a polymer unit attached to aa, each SU is a sugar unit attached to aa; each CU is a carboxyl unit attached to aa; double wavy ( The line indicates an attachment site for at least one of the drug units; wherein each of aa, aa1, and aa2 is a linker compound independently selected from alpha, beta, and gamma amino acids and their derivatives.

[1142] Embodiment 93. A linker compound in any one of Embodiments 1-92, wherein the linker unit is a cleavable linker unit.

[1143] Embodiment 94. A linker compound in which, in any one of Embodiments 1-92, the enzyme-cleavable group comprises a peptide cleavable by an intracellular protease.

[1144] Embodiment 95. A linker compound of Embodiment 94 in which the intracellular protease is cathepsin B.

[1145] Embodiment 96. The linker compound of Embodiment 94, wherein the enzyme-cleavable group comprises a cleavable peptide including a valine-citrulline peptide, a valine-alanine peptide, a valine-lysine peptide, a phenylalanine-lysine peptide, or a glycine-glycine-phenylalanine-glycine peptide.

[1146] Embodiment 97. A linker compound in which, in any one of Embodiments 94-96, a cleavable peptide is attached to a para-aminobenzyl alcohol self-sacrificial group (PABA).

[1147] Embodiment 98. In any one of Embodiments 1-14, comprising one of the following structures:

[1148]

[1149]

[1150]

[1151]

[1152]

[1153]

[1154]

[1155]

[1156]

[1157]

[1158]

[1159] ,

[1160] Here

[1161] R c is a bond or C1-6 alkylene;

[1162] The wavy line on the amino group indicates the attachment site to the stretcher group, or indicates H prior to attachment to the stretcher group;

[1163] β- is the attachment site for the POLY unit;

[1164] A linker compound in which the H on the benzylic OH is optionally replaced by bonding to at least one of the drug units or to an attachment site to at least one of the drug units.

[1165] Embodiment 99. In any one of Embodiments 1-14, having one of the following structures:

[1166]

[1167]

[1168]

[1169]

[1170]

[1171]

[1172]

[1173]

[1174]

[1175]

[1176]

[1177]

[1178]

[1179]

[1180]

[1181]

[1182]

[1183]

[1184]

[1185]

[1186]

[1187]

[1188] ,

[1189] A linker compound wherein the wavy line on the amino group indicates an attachment site to the stretcher group; or H indicates an attachment site to the stretcher group, and the H on the benzylic OH is optionally replaced by a bond to at least one of the drug units or to a linker attached to at least one of the drug units.

[1190] Embodiment 100. In any one of Embodiments 1 to 14, comprising one of the following structures:

[1191]

[1192]

[1193]

[1194]

[1195]

[1196]

[1197]

[1198]

[1199] ,

[1200] Here, wavy lines on the oxygen group or *-amino group represents an attachment site for at least one of the drug units or for a linker attached to at least one of the drug units; and a wavy line on the amino group A linker compound that represents an attachment site for a stretcher group or an amino acid unit, or represents H prior to attachment.

[1201] Embodiment 101. A linker compound in any one of Embodiments 1 to 100, wherein the enzyme-cleavable group is connected to the stretch group by a non-peptide linker.

[1202] Embodiment 102. In Embodiment 101, a C1-C in which a non-peptide linker is optionally substituted.10 Alkylene, optionally substituted C2-C 10 Alkenylene, arbitrarily substituted C2-C 10 A linker compound selected from alkynylene or optionally substituted polyethylene glycol.

[1203] Embodiment 103. A linker compound comprising a stretcher group attached to an enzyme-cleavable group in any one of Embodiments 1-102.

[1204] Embodiment 104. In Embodiment 103, the stretcher is selected from the following:

[1205] ,

[1206] Here, R 17 -C1-C 10 Alkylene-, -C1-C 10 Heteroalkylene-, -C3-C8carbocyclo-, -O-(C1-C8alkylene)-, -(CH2-O-CH2) b -C1-C8alkylene- (where b is 1 to 26), -C1-C8alkylene-(CH2-O-CH2) b - (where b is 1 to 26), -C1-C8alkylene-(CH2-O-CH2) b -C1-C8alkylene- (where b is 1 to 26), -arylene-, -C1-C 10 Alkylene-arylene-, -arylene-C1-C 10 Alkylene-, -C1-C 10 Alkylene-(C3-C8 carbocyclo)-, -(C3-C8 carbocyclo)-C1-C 10 Alkylene-, -C3-C8 heterocyclo-, -C1-C 10 Alkylene-(C3-C8 heterocyclo)-, -(C3-C8 heterocyclo)-C1-C 10 Alkylene-, -C1-C 10 Alkylene-C(=O)-, -C1-C 10 Alkylene-C(O)NH-C1-C8alkylene-[O-CH2-CH2] n -C(O)- (where n is 1 to 26), C1-C 10Heteroalkylene-C(=O)-, -C1-C8alkylene-(CH2-O-CH2) b -C(=O)- (where b is 1 to 26), -(CH2-O-CH2) b -C1-C8alkylene-C(=O)- (where b is 1 to 26), -C1-C8alkylene-(CH2-O-CH2) b -C1-C8alkylene-C(=O)- (where b is 1 to 26), -C3-C8carbocyclo-C(=O)-, -O-(C1-C8alkyl)-C(=O)-, -arylene-C(=O)-, -C1-C 10 Alkylene-arylene-C(=O)-, -arylene-C1-C 10 Alkylene-C(=O)-, -C1-C 10 Alkylene-(C3-C8 carbocyclo)-C(=O)-, -(C3-C8 carbocyclo)-C1-C 10 Alkylene-C(=O)-, -C3-C8 heterocyclo-C(=O)-, -C1-C 10 Alkylene-(C3-C8 heterocyclo)-C(=O)-, -(C3-C8 heterocyclo)-C1-C 10 Alkylene-C(=O)-, -C1-C 10 Alkylene-NH-, -C1-C 10 Heteroalkylene-NH-, -C1-C8alkylene-(CH2-O-CH2) b -NH- (where b is 1 to 26), -(CH2-O-CH2) b -C1-C8alkylene-NH- (where b is 1 to 26), -C1-C8alkylene-(CH2-O-CH2) b -C1-C8alkylene-NH- (where b is 1 to 26), -C1-C8alkylene-(C(=O))-NH-(CH2-O-CH2) b -C(=O)- (where b is 1 to 26), -C1-C8alkylene-(C(=O))-NH-(CH2-O-CH2) b -C1-C8alkylene-C(=O)- (where b is 1 to 26), -C1-C8alkylene-NH-(C(=O))-(CH2-O-CH2) b-NH- (where b is 1 to 26), -C1-C8alkylene-NH-(C(=O))-(CH2-O-CH2) b -C1-C8alkylene-NH- (where b is 1 to 26), -C3-C8carbocyclo-NH-, -O-(C1-C8alkyl)-NH-, -arylene-NH-, -C1-C 10 Alkylene-arylene-NH-, -arylene-C1-C 10 Alkylene-NH-, -C1-C 10 Alkylene-(C3-C8 carbocyclo)-NH-, -(C3-C8 carbocyclo)-C1-C 10 Alkylene-NH-, -C3-C8 heterocyclo-NH-, -C1-C 10 Alkylene-(C3-C8 heterocyclo)-NH-, -(C3-C8 heterocyclo)-C1-C 10 Alkylene-NH-, -C1-C 10 Alkylene-S-, C1-C 10 Heteroalkylene-S-, -C3-C8carbocyclo-S-, -O-(C1-C8alkyl)-S-, -arylene-S-, -C1-C 10 Alkylene-arylene-S-, -arylene-C1-C 10 Alkylene-S-, -C1-C 10 Alkylene-(C3-C8 carbocyclo)-S-, -(C3-C8 carbocyclo)-C1-C 10 Alkylene-S-, -C3-C8 heterocyclo-S-, -C1-C 10 Alkylene-(C3-C8 heterocyclo)-S-, or -(C3-C8 heterocyclo)-C1-C 10 Alkylene-S- or; or

[1207] Here, the stretcher group is the malaiimido (C1-C 10 Alkylene-C(O)-, maleimido(CH2OCH2) p2 (C1-C 10 Alkylene)C(O)-, maleimido(C1-C 10 Alkylene) (CH2OCH2) p2 C(O)-, or its ring-opening form, wherein p2 is 1 to 26;

[1208] Here, * is the attachment to the SLITRK6 binder, and the wavy line is the attachment to the enzyme-cleavable group, a linker compound.

[1209] Embodiment 105. In Embodiment 104, the stretcher machine is as follows:

[1210]

[1211] or selected from its stereoisomers, where each R a is independently H or C 1-6 It is alkyl, and each n is independently 0-12, and wavy A linker compound in which the attachment site of the stretcher group to the amino acid unit is located on a maleimide, primary amine, or alkyne functional group, and the attachment site to the targeting unit is located on the maleimide, primary amine, or alkyne functional group.

[1212] Embodiment 106. In Embodiment 104, the stretcher is selected from the following:

[1213]

[1214] Here, the wavy line A linker compound in which the attachment site of the stretcher group to the enzyme-cleavable group is located on a maleimide, primary amine, or alkyne functional group, and the attachment site to the SLITRK6 binder is located on the maleimide, primary amine, or alkyne functional group.

[1215] Embodiment 107. In any one of Embodiments 1-9, having one of the following structures:

[1216]

[1217]

[1218]

[1219]

[1220]

[1221]

[1222]

[1223]

[1224]

[1225]

[1226]

[1227]

[1228]

[1229]

[1230]

[1231]

[1232]

[1233]

[1234]

[1235]

[1236]

[1237]

[1238] A linker compound in which the H on the benzylic OH is optionally replaced by a bond to at least one drug unit or to a linker attached to at least one drug unit.

[1239] Embodiment 108. In any one of Embodiments 1-9, one of the following structures:

[1240]

[1241]

[1242]

[1243]

[1244]

[1245]

[1246]

[1247]

[1248] or having its stereoisomer, where the wavy line A linker compound that represents an attachment site for at least one of the drug units or for a linker attached to at least one of the drug units.

[1249] Embodiment 109. A drug-linker compound comprising any one of the linker compounds of Embodiments 1-108, attached to at least one drug unit or attached to a linker attached to at least one drug unit.

[1250] Embodiment 110. A drug-linker compound according to Embodiment 109, wherein the drug unit is selected from cytotoxic agents, immunomodulators, nucleic acids, growth inhibitors, PROTACs, toxins, radioisotopes, and chelating ligands.

[1251] Embodiment 111. In Embodiment 111, a drug-linker compound in which the drug unit is a cytotoxic agent.

[1252] Embodiment 112. A drug-linker compound according to Embodiment 111, wherein the cytotoxic agent is selected from the group consisting of auristatin, meitansinoid, camptothecin, duocarmycin, and caliceamicin.

[1253] Embodiment 113. A drug-linker compound according to Embodiment 111, wherein the cytotoxic agent is auristatin.

[1254] Embodiment 114. A drug-linker compound according to Embodiment 113, wherein the cytotoxic agent is MMAE or MMAF.

[1255] Embodiment 115. A drug-linker compound in which the cytotoxic agent of Embodiment 111 is camptothecin.

[1256] Embodiment 116. A drug-linker compound according to Embodiment 115, wherein the cytotoxic agent is exatecan, or SN-38, or DxD.

[1257] Embodiment 117. A drug-linker compound according to Embodiment 116, wherein the cytotoxic agent is RS-exatecan or SS-exatecan.

[1258] Embodiment 118. A drug-linker compound according to Embodiment 111, wherein the cytotoxic agent is caliceamycin.

[1259] Embodiment 119. A drug-linker compound according to Embodiment 111, wherein the cytotoxic agent is a metansinoid.

[1260] Embodiment 120. A drug-linker compound in which the metansinoid of Embodiment 119 is metansin, metansinol, or ansamatosin-2.

[1261] Embodiment 121. The drug-linker in Embodiment 112, wherein the cytotoxic agent is MMAE, MMAF, exatecan, RS-exatecan, SS-exatecan, SN-38, DxD, metansin, metansinol, or ansamatosin-2.

[1262] Embodiment 122. A drug-linker compound according to Embodiment 112, wherein the cytotoxic agent is MMAE.

[1263] Embodiment 123. A drug-linker compound according to Embodiment 112, wherein the cytotoxic agent is exatecan.

[1264] Embodiment 124. A drug-linker compound in which the drug unit of Embodiment 110 is an immunomodulator.

[1265] Embodiment 125. A drug-linker compound according to Embodiment 124, wherein the immunomodulator is selected from TRL7 agonists, TLR8 agonists, STING agonists, or RIG-I agonists.

[1266] Embodiment 126. A drug-linker compound in which the immunomodulator of Embodiment 125 is a TLR7 agonist.

[1267] Embodiment 127. The drug-linker compound of Embodiment 126, wherein the TLR7 agonist is imidazoquinoline, imidazoquinoline amine, thiazquinoline, aminoquinoline, aminoquinazolin, pyrido[3,2-d]pyrimidine-2,4-diamine, pyrimidine-2,4-diamine, 2-aminoimidazole, 1-alkyl-1H-benzimidazole-2-amine, tetrahydropyridopyrimidine, heteroarothiazide-2,2-dioxide, benzonaphthalidine, guanosine analog, adenosine analog, thymidine homopolymer, ssRNA, CpG-A, polyG10, or polyG3.

[1268] Embodiment 128. A drug-linker compound in which the immunomodulator of Embodiment 126 is a TLR8 agonist.

[1269] Embodiment 129. A drug-linker compound according to Embodiment 128, wherein the TLR8 agonist is selected from imidazoquinoline, thiazoloquinoline, aminoquinoline, aminoquinazolin, pyrido[3,2-d]pyrimidine-2,4-diamine, pyrimidine-2,4-diamine, 2-aminoimidazole, 1-alkyl-1H-benzimidazole-2-amine, tetrahydropyridopyrimidine, or ssRNA.

[1270] Embodiment 130. A drug-linker compound in which the immunomodulator of Embodiment 125 is a STING agonist.

[1271] Embodiment 131. A drug-linker compound in which the immunomodulator of Embodiment 125 is a RIG-I agonist.

[1272] Embodiment 132. A drug-linker compound according to Embodiment 131, wherein the RIG-I agonist is selected from KIN1148, SB-9200, KIN700, KIN600, KIN500, KIN100, KIN101, KIN400 and KIN2000.

[1273] Embodiment 133. A drug-linker compound according to Embodiment 110, wherein the drug unit is a chelating ligand.

[1274] Embodiment 134. A drug-linker compound according to Embodiment 133, wherein the chelating ligand is selected from platinum (Pt), ruthenium (Ru), rhodium (Rh), gold (Au), silver (Ag), copper (Cu), molybdenum (Mo), titanium (Ti), or iridium (Ir); and radioisotopes, e.g., yttrium-88, yttrium-90, technetium-99, copper-67, rhenium-188, rhenium-186, gallium-66, gallium-67, indium-111, indium-114, indium-115, lutetium-177, strontium-89, samarium-153, and lead-212.

[1275] Embodiment 135. In Embodiment 109, a drug-linker compound having one of the following structures:

[1276]

[1277]

[1278]

[1279]

[1280]

[1281]

[1282]

[1283]

[1284]

[1285]

[1286]

[1287]

[1288]

[1289]

[1290]

[1291]

[1292]

[1293]

[1294]

[1295]

[1296]

[1297]

[1298]

[1299]

[1300] .

[1301] Embodiment 136. In Embodiment 109, one of the following structures:

[1302]

[1303]

[1304]

[1305]

[1306]

[1307]

[1308]

[1309]

[1310] ,

[1311] or a drug-linker compound having its stereoisomer.

[1312] Embodiment 137. A conjugate comprising a drug-linker compound of any one of Embodiments 109-136, wherein the drug-linker compound is attached to a binder (e.g., SLITRK6 binder).

[1313] Embodiment 138. In Embodiment 137, the average drug loading of the conjugate (p로드 A composite in which ) is about 1 to about 8, about 2, about 4, about 6, about 8, about 10, about 12, about 14, about 16, about 3 to about 5, about 6 to about 8, or about 8 to about 16.

[1314] Embodiment 139. In any one of Embodiments 137-138, the following:

[1315]

[1316]

[1317]

[1318]

[1319]

[1320]

[1321]

[1322]

[1323]

[1324]

[1325]

[1326]

[1327]

[1328]

[1329]

[1330]

[1331]

[1332]

[1333]

[1334]

[1335]

[1336]

[1337]

[1338] ,

[1339] or is selected from its stereoisomers, where Ab is a SLITRK6 binder and n is p 로드 Human conjugate.

[1340] Embodiment 140. In any one of Embodiments 137-138, the following:

[1341]

[1342]

[1343]

[1344]

[1345]

[1346]

[1347]

[1348]

[1349] ,

[1350] or is selected from its stereoisomers, where Ab is a SLITRK6 binder and n is p 로드 Human conjugate.

[1351] Embodiment 141. In any one of Embodiments 137-138, the following:

[1352] LD110 assembly

[1353]

[1354] LD163 assembly

[1355]

[1356] LD038 assembly

[1357]

[1358] LD343 assembly

[1359]

[1360] or is selected from its stereoisomers, where Ab is a SLITRK6 binder and n is p 로드 Human conjugate.

[1361] Embodiment 142. Any one of Embodiments 137-141, wherein Ab is a SLITRK6 binder (e.g., an antibody that binds to SLITRK6 or its antigen-binding portion) comprising a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, a...

Claims

Claim 1 A binder for binding to SLIT and NTRK-like protein 6 (SLITRK6), comprising a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises complementarity determining regions HCDR1, HCDR2, and HCDR3 located in the heavy chain variable region framework region, and the VL region comprises LCDR1, LCDR2, and LCDR3 located in the light chain variable region framework region, and the VH and VL CDRs comprise amino acid sequences selected from the set of amino acid sequences presented in the group consisting of: (i) each of sequence identification number: 19, sequence identification number: 20, sequence identification number: 21, sequence identification number: 22, sequence identification number: 23, and sequence identification number: 24; (ii) each of sequence identification number: 11, sequence identification number: 12, sequence identification number: 13, sequence identification number: 14, sequence identification number: 15, and sequence identification number: 16;(iii) each sequence identification number: 3, sequence identification number: 4, sequence identification number: 5, sequence identification number: 6, sequence identification number: 7 and sequence identification number: 8;(iv) each sequence identification number: 27, sequence identification number: 28, sequence identification number: 29, sequence identification number: 30, sequence identification number: 31 and sequence identification number: 32; and (v) each sequence identification number: 35, sequence identification number: 36, sequence identification number: 37, sequence identification number: 38, sequence identification number: 39 and sequence identification number:

40. Claim 2 A binder according to claim 1, wherein the VH and VL regions comprise amino acid sequences selected from amino acid sequence pairs presented in the group consisting of: (i) each of sequence identification number: 17 and sequence identification number: 18; (ii) each of sequence identification number: 9 and sequence identification number: 10; (iii) each of sequence identification number: 1 and sequence identification number: 2; (iv) each of sequence identification number: 25 and sequence identification number: 26; and (v) each of sequence identification number: 33 and sequence identification number:

34. Claim 3 In claim 1, the VH and VL regions comprise amino acid sequences selected from amino acid sequence pairs presented in the group consisting of: (i) each of sequence identification number: 1 and sequence identification number: 2; (ii) each of sequence identification number: 9 and sequence identification number: 10; (iii) each of sequence identification number: 17 and sequence identification number: 18; (iv) each of sequence identification number: 25 and sequence identification number: 26; and (v) each of sequence identification number: 33 and sequence identification number: 34; wherein the heavy chain and light chain framework regions are optionally modified by 1 to 8 amino acid substitutions, deletions, or insertions in the framework regions. Claim 4 A binder according to any one of claims 1 to 3, wherein HCDR1, HCDR2, and HCDR3 and LCDR1, LCDR2, and LCDR3 each comprise the amino acid sequences presented in sequence identification number: 19, sequence identification number: 20, sequence identification number: 21, sequence identification number: 22, sequence identification number: 23, and sequence identification number:

24. Claim 5 A binder according to any one of claims 1 to 4, wherein the VH and VL regions each comprise the amino acid sequences of sequence identification numbers: 17 and 18. Claim 6 A binder in which the framework area is a human framework area, as in paragraph 1 or 4. Claim 7 A binder that is an antibody or its antigen-binding portion in any one of paragraphs 1 to 6. Claim 8 A binder according to any one of claims 1 to 7, wherein the binder is a monoclonal antibody, Fab, Fab', F(ab'), Fv, disulfide-linked Fc, scFv, single-domain antibody, diabody, bispecific antibody, or multispecific antibody. Claim 9 A binder according to any one of claims 1 to 8, wherein the heavy chain variable region further comprises a heavy chain invariant region. Claim 10 In paragraph 9, a binder in which the heavy chain constant region is an IgG isoform. Claim 11 In Clause 10, a binder in which the heavy chain constant region is the IgG1 constant region. Claim 12 In Clause 10, a binder in which the heavy chain constant region is an IgG4 constant region. Claim 13 A binder according to claim 10, wherein the heavy chain constant comprises the amino acid sequence presented in sequence identification number: 49, 51, or 52. Claim 14 A binder according to any one of claims 1 to 13, wherein the light chain variable region additionally includes a light chain invariant region. Claim 15 In paragraph 14, a binder in which the light chain constant region is of the kappa isotype. Claim 16 A binder according to claim 15, wherein the light chain constant region has the amino acid sequence presented in sequence identification number:

50. Claim 17 A binder according to any one of claims 9 to 13, wherein the heavy chain constant region further comprises an amino acid modification that reduces the binding affinity for at least human FcγRIII. Claim 18 A binder comprising a heavy chain and a light chain, each comprising the amino acid sequences presented in sequence identification numbers 53 and 55, in any one of claims 1 to 17. Claim 19 A binder comprising a heavy chain and a light chain, each comprising the amino acid sequences presented in sequence identification numbers 54 and 55, in any one of claims 1 to 17. Claim 20 A single specific binder in any one of claims 1 to 19. Claim 21 A divalent binder in any one of paragraphs 1 to 20. Claim 22 A double-specific binder in any one of claims 1 to 19. Claim 23 A nucleic acid encoding a binder of any one of paragraphs 1 to 22. Claim 24 A vector containing the nucleic acid of paragraph 23. Claim 25 A cell line comprising the vector of claim 24 or the nucleic acid of claim 23. Claim 26 A conjugate comprising: a binder according to any one of claims 1 to 22; at least one linker attached to the binder; and at least one drug unit, wherein each drug unit is attached to the linker, and wherein the linker optionally comprises at least one polar group. Claim 27 A conjugate according to claim 26, wherein the linker is derived from a linker compound or its stereoisomer or salt, and the linker compound comprises: a linker unit; a stretcher group connected to the linker unit, optionally an amino acid unit; and at least one polar group; wherein the stretcher group has an attachment site for a binder and an attachment site for an amino acid unit (if present) or a linker subunit; the amino acid unit (if present) has an attachment site for a stretcher group and an attachment site for a linker unit; and the linker unit has an attachment site for an amino acid unit (if present) or a stretcher group and at least one drug unit. Claim 28 A conjugate according to claim 26 or 27, wherein the drug unit is selected from cytotoxic agents, immunomodulators, nucleic acids, growth inhibitors, PROTACs, toxins, radioisotopes, and chelating ligands. Claim 29 In any one of paragraphs 26 to 28, the average drug loading of the conjugate (p 로드 A composite in which ) is about 1 to about 8, about 2, about 4, about 6, about 8, about 10, about 12, about 14, about 16, about 3 to about 5, about 6 to about 8, or about 8 to about 16. Claim 30 In paragraph 29, the average p of the conjugate 로드 A junction of approximately 8 people. Claim 31 In any one of paragraphs 26 through 30, selected from the following: Here, Ab is the binder, and n is p 로드 Human conjugate. Claim 32 In Clause 26, having the following structure: LD110 assembly ,LD163 conjugate, ,LD038 conjugate, , or LD343 conjugate Here, Ab is the binder, and n is p 로드 and, here p 로드 A composite that is about 1 to about 8, about 2, about 4, about 6, about 8, about 10, about 12, about 14, about 16, about 3 to about 5, about 6 to about 8, or about 8 to about 16. Claim 33 As a composite comprising the following structure: Here, Ab is an antibody or its antigen-binding portion that binds to SLIT and NTRK-like protein 6 (SLITRK6), wherein the antibody comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises the VHCDR1, VHCDR2, and VHCDR3 sequences presented in Sequence Identification Nos. 19, 20, and 21, respectively, and the VL region comprises the VLCDR1, VLCDR2, and VLCDR3 sequences presented in Sequence Identification Nos. 22, 23, and 24, respectively, where n is p 로드 and, here p 로드 A composite that is about 1 to about 8, about 2, about 4, about 6, about 8, about 10, about 12, about 14, about 16, about 3 to about 5, about 6 to about 8, or about 8 to about 16. Claim 34 As a composite comprising the following structure: Here, Ab is an antibody or its antigen-binding portion that binds to SLIT and NTRK-like protein 6 (SLITRK6), wherein the antibody comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises the VHCDR1, VHCDR2, and VHCDR3 sequences presented in Sequence Identification Nos. 19, 20, and 21, respectively, and the VL region comprises the VLCDR1, VLCDR2, and VLCDR3 sequences presented in Sequence Identification Nos. 22, 23, and 24, respectively, where n is p 로드 and, here p 로드 A composite that is about 1 to about 8, about 2, about 4, about 6, about 8, about 10, about 12, about 14, about 16, about 3 to about 5, about 6 to about 8, or about 8 to about 16. Claim 35 As a composite comprising the following structure: Here, Ab is an antibody or its antigen-binding portion that binds to SLIT and NTRK-like protein 6 (SLITRK6), wherein the antibody comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises the VHCDR1, VHCDR2, and VHCDR3 sequences presented in Sequence Identification Nos. 19, 20, and 21, respectively, and the VL region comprises the VLCDR1, VLCDR2, and VLCDR3 sequences presented in Sequence Identification Nos. 22, 23, and 24, respectively, where n is p 로드 and, here p 로드 A composite that is about 1 to about 8, about 2, about 4, about 6, about 8, about 10, about 12, about 14, about 16, about 3 to about 5, about 6 to about 8, or about 8 to about 16. Claim 36 As a composite comprising the following structure: Here, Ab is an antibody or its antigen-binding portion that binds to SLIT and NTRK-like protein 6 (SLITRK6), wherein the antibody comprises a heavy chain variable (VH) region and a light chain variable (VL) region, wherein the VH region comprises the VHCDR1, VHCDR2, and VHCDR3 sequences presented in Sequence Identification Nos. 19, 20, and 21, respectively, and the VL region comprises the VLCDR1, VLCDR2, and VLCDR3 sequences presented in Sequence Identification Nos. 22, 23, and 24, respectively, where n is p 로드 and, here p 로드 A composite that is about 1 to about 8, about 2, about 4, about 6, about 8, about 10, about 12, about 14, about 16, about 3 to about 5, about 6 to about 8, or about 8 to about 16. Claim 37 A conjugate according to any one of claims 33 to 36, wherein the VH and VL regions each comprise the amino acid sequences presented in sequence identification numbers 17 and 18. Claim 38 A conjugate according to any one of claims 33 to 37, wherein the antibody comprises a heavy chain and a light chain each comprising the amino acid sequences of sequence identification numbers: 53 and 55. Claim 39 A conjugate according to any one of claims 33 to 37, wherein the antibody comprises a heavy chain and a light chain each comprising the amino acid sequences of sequence identification numbers: 54 and 55. Claim 40 A pharmaceutical composition comprising a binder according to any one of claims 1 to 22 or a conjugate according to any one of claims 26 to 39 and a pharmaceutically acceptable carrier. Claim 41 A method for treating cancer, preferably SLITRK6+ cancer, comprising administering a therapeutically effective amount of the binder of any one of claims 1 to 22, the conjugate of any one of claims 26 to 39, or the pharmaceutical composition of claim 40 to a subject requiring treatment for cancer, preferably SLITRK6+ cancer. Claim 42 A binder, conjugate, or pharmaceutical composition for use as a medicine in any one of paragraphs 1 to 22 and 26 to 40. Claim 43 A binder, conjugate, or pharmaceutical composition according to any one of claims 1 to 22 and claims 26 to 40, intended for use in the treatment of cancer in a subject, preferably wherein the cancer is SLITRK6+ cancer. Claim 44 Use of a binder of any one of claims 1 to 22, a conjugate of any one of claims 26 to 39, or a pharmaceutical composition of claim 40 for the manufacture of a medicine. Claim 45 A use of a binder of any one of claims 1 to 22, a conjugate of any one of claims 26 to 39, or a pharmaceutical composition of claim 40 for the manufacture of a medicine for the treatment of cancer in a subject, preferably the use in which the cancer is SLITRK6+ cancer. Claim 46 A method, binder, conjugate, or pharmaceutical composition, or use according to any one of claims 41, 43, and 45, wherein the SLITRK6+ cancer is a solid tumor or a hematological malignancy. Claim 47 A method, binder, conjugate, or pharmaceutical composition, or use according to any one of claims 41, 43, and 45, wherein the SLITRK6+ cancer is selected from breast cancer (BC), lung cancer (LC), ovarian cancer (OVCA), esophageal cancer (EsC), gastric cancer (GC), bladder cancer (BLC), endometrial cancer (EC), head and neck cancer (HNC), cervical cancer, pharyngeal cancer, gastric cancer, multiple myeloma, uterine cancer, colon cancer, hepatocellular carcinoma, and colorectal cancer. Claim 48 A method for treating an autoimmune disease, comprising administering a therapeutically effective amount of a binder of any one of claims 1 to 22, a conjugate of any one of claims 26 to 39, or a pharmaceutical composition of claim 40 to a subject requiring treatment for an autoimmune disease. Claim 49 A binder, conjugate, or pharmaceutical composition for use in the treatment of an autoimmune disease in a subject, in any one of claims 1 to 22 and 26 to 40. Claim 50 Use of a binder of any one of claims 1 to 22, a conjugate of any one of claims 26 to 39, or a pharmaceutical composition of claim 40 for the manufacture of a medicine for the treatment of an autoimmune disease in a subject. Claim 51 A method, binder, conjugate, or pharmaceutical composition, or use according to any one of claims 48 to 50, wherein the autoimmune disease is rheumatoid arthritis, multiple sclerosis, or systemic lupus erythematosus. Claim 52 A method for producing a binder that binds to SLITRK6, comprising the steps of culturing the cell line of claim 25 and isolating the binder from the cell. Claim 53 An anti-idiotype antibody that binds to a binder of any one of claims 1 to 22.

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