Interleukin-13 receptor subunit alpha-2 binding agents and uses thereof

Abstract

The present disclosure provides IL13Rα2 binding agents (e.g, antibodies, including monospecific and multispecific antibodies such as bispecific antibodies) and uses thereof.

Description

INTERLEUKIN-13 RECEPTOR SUBUNIT ALPHA-2 BINDING AGENTS AND USES THEREOFCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 514,790, filed July 20, 2023, the disclosure of which is incorporated by reference herein in its entirety.SEQUENCE LISTING

[0002] This application contains an electronic Sequence Listing which has been submitted in XML file format with this application, the entire content of which is incorporated by reference herein in its entirety. The Sequence Listing XML file submitted with this application is entitled “14529-144-228_SEQ_LISTING.xml”, was created on July 15, 2024, and is 110,551 bytes in size.1. FIELD

[0003] The present disclosure relates generally to binding agents, such as antibodies (including fragments thereof) that bind to Interleukin- 13 receptor a2 (IL13Ra2) including human IL13Ra2, and methods of use thereof.2. BACKGROUND

[0004] Interleukin- 13 receptor subunit alpha-2 (IL-13Ra2 or IL13Ra2), also known as CD213A2 (cluster of differentiation 213 A2), is a membrane bound protein that in humans is encoded by the IL13Ra2 gene. IL-13Ra2 is a high-affinity membrane receptor for the antiinflammatory cytokine interleukin 13 (IL- 13). IL-13Ra2 has been found to be over-expressed in a variety of cancers, including but not limited to malignant melanomas, malignant gliomas, pancreatic, ovarian, breast, liver, head and neck, and renal cancers.3. SUMMARY

[0005] The present disclosure provides IL13Ra2 binding agents, including human IL13Ra2 binding agents. Such agents include antibodies that bind to IL13Ra2 (or a complex comprising IL13Ra2 and IL13, referred to herein as an IL13Ra2:IL13 complex), for example, monospecific or multispecific (e.g., bispecific) antibodies that bind to IL13Ra2 (or an IL13Ra2:IL13 complex). Such binding agents, in some embodiments, bind to the same epitope of IL13Ra2 (or an IL13Ra2:IL13 complex) (e.g., human IL13Ra2) as an antibody comprising the CDRs described herein (e.g., Tables 1-3). Such binding agents, in some embodiments, bind to the same epitope of IL13Ra2 (or an IL13Ra2:IL13 complex) (e.g.,human IL13Ra2) as an antibody comprising a heavy chain variable region and a light chain variable region described herein (e.g., Tables 1-3).

[0006] The present disclosure also provides nucleic acids encoding an IL13Ra2 binding agent provided herein (e.g., an antibody or fragment thereof, such as an antigen-binding fragment), vectors comprising one or more of such nucleic acids, and cells comprising the nucleic acid, the vector, or both (such as cells expressing the binding agent).

[0007] The present disclosure also provides compositions comprising an IL13Ra2 binding agent. Such compositions, in some embodiments, include antibodies that bind to IL13Ra2 (or an IL13Ra2:IL13 complex), for example, monospecific or multispecific (e.g., bispecific) antibodies that bind to IL13Ra2 (or an IL13Ra2:IL13 complex). Such compositions, in some embodiments, include antibodies that bind to essentially the same epitope of IL13Ra2 (or an IL13Ra2:IL13 complex) (e.g., human IL13Ra2) as an antibody comprising the CDRs described herein (e.g., Tables 1-3). Such compositions, in some embodiments, include antibodies that bind to essentially the same epitope of IL13Ra2 (or an IL13Ra2:IL13 complex) (e.g., human IL13Ra2) as an antibody comprising a heavy chain variable region and a light chain variable region described herein (e.g., Tables 1-3).

[0008] In some embodiments, the binding agent binds to IL13Ra2. Additionally or alternatively, the binding agent binds to a complex comprising IL13Ra2 and IL13 (referred to herein as an IL13Ra2:IL13 complex). Additionally or alternatively, the binding agent does not bind to IL13Ral. In some embodiments, the binding agent binds to a complex comprising IL13Ra2 and IL13 but lacking IL13Ral. In some embodiments, the binding agent does not block the binding between IL13 and IL13Ra2 (e.g., human IL13Ra2 and / or cyno IL13Ra2).

[0009] The present disclosure also provides compositions comprising the nucleic acids encoding an IL13Ra2 binding agent provided herein (e.g., an antibody or fragment thereof, such as an antigen-binding fragment), vectors comprising one or more nucleic acids, or cells comprising the nucleic acid, the vector, or both (such as cells expressing the binding agent).

[0010] The present disclosure further provides various uses of the present binding agents and compositions, including, for example, methods for identifying a cell expressing IL13Ra2, methods for reducing (including but not limited to abolishing) viability or proliferation of an IL13Ra2-expressing cell, and methods for killing an IL13Ra2-expressing cell. In further embodiments, the IL13Ra2-expressing cell is a cancer cell. In further embodiments, the cancer cell is a melanoma cell, lung cancer (including non-small cell lung cancer) cell, or colorectal cancer cell. Other aspects provided herein include methods for treating a disease or disorder in a subject with an IL13Ra2 binding agent or a composition provided herein. Suchcompositions include antibodies that bind to IL13Ra2 (or an IL13Ra2:IL13 complex), for example, monospecific or multispecific (e.g., bispecific) antibodies that bind to IL13Ra2 (or an IL13Ra2:IL13 complex) (e.g., human IL13Ra2). In some embodiments, the disease or disorder is cancer. In some embodiments, the cancer is melanoma, lung cancer (including non-small cell lung cancer), or colorectal cancer. In some embodiments, the cancer treated in accordance with the methods described herein expresses (including overexpresses) IL13Ra2.4. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIGs. 1A-1E provide exemplary monovalent Kd results of A22 (FIG. 1A), A33 (FIG. IB), A52 (FIG. 1C), benchmark antibody 1 (FIG. ID), and benchmark antibody 2 (FIG. IE), as further illustrated in Example 2.

[0012] FIGs. 2A-2E provide exemplary SEC results of A22 (FIG. 2A), A33 (FIG. 2B), A52 (FIG. 2C), benchmark antibody 1 (FIG. 2D), and benchmark antibody 2 (FIG. 2E), as further illustrated in Example 4.

[0013] FIGs. 3A-3E provide exemplary SCX results of A22 (FIG. 3A), A33 (FIG. 3B), A52 (FIG. 3C), benchmark antibody 1 (FIG. 3D), and benchmark antibody 2 (FIG. 3E), as further illustrated in Example 4.

[0014] FIGs. 4A-4E provide exemplary SMAC results of A22 (FIG. 4A), A33 (FIG. 4B), A52 (FIG. 4C), benchmark antibody 1 (FIG. 4D), and benchmark antibody 2 (FIG. 4E), as further illustrated in Example 4.

[0015] FIGs. 5A-5E provide exemplary HIC results of A22 (FIG. 5A), A33 (FIG. 5B), A52 (FIG. 5C), benchmark antibody 1 (FIG. 5D), and benchmark antibody 2 (FIG. 5E), as further illustrated in Example 4.

[0016] FIGs. 6A-6E provide exemplary binding results of A22 (FIG. 6A), A33 (FIG. 6B), A52 (FIG. 6C), benchmark antibody 1 (FIG. 6D), and benchmark antibody 2 (FIG. 6E), to IL13Ra2 endogenously expressed on A375 cells, as further illustrated in Example 5.

[0017] FIGs. 7A-7E provide exemplary binding results of A22 (FIG. 7A), A33 (FIG. 7B), A52 (FIG. 7C), benchmark antibody 1 (FIG. 7D), and benchmark antibody 2 (FIG. 7E), to human IL13Ra2 expressed on HEK cells, as further illustrated in Example 5.

[0018] FIGs. 8A-8E provide exemplary binding results of A22 (FIG. 8A), A33 (FIG. 8B), A52 (FIG. 8C), benchmark antibody 1 (FIG. 8D), and benchmark antibody 2 (FIG. 8E), to cyno IL13Ra2 expressed on HEK cells, as further illustrated in Example 5.

[0019] FIGs. 9A-9E provide exemplary binding results of A22 (FIG. 9A), A33 (FIG. 9B), A52 (FIG. 9C), benchmark antibody 1 (FIG. 9D), and benchmark antibody 2 (FIG. 9E), toIL13Ra2 endogenously expressed on A375 cells pretreated with human IL13, as further illustrated in Example 5.

[0020] FIGs. 10A-10E provide exemplary binding results of A22 (FIG. 10A), A33 (FIG. 10B), A52 (FIG. 10C), benchmark antibody 1 (FIG. 10D), and benchmark antibody 2 (FIG. 10E), to human IL13Ra2 expressed on HEK cells pretreated with human IL13, as further illustrated in Example 5.

[0021] FIGs. 11A-11E provide exemplary ADC piggy-back assay results of A22 (FIG.11 A), A33 (FIG. 11B), A52 (FIG. 11C), benchmark antibody 1 (FIG. 11D), and benchmark antibody 2 (FIG. HE), in A375 cells endogenously expressing IL13Ra2, as further illustrated in Example 6.

[0022] FIGs. 12A-12E provide exemplary ADC piggy-back assay results of A22 (FIG. 12A), A33 (FIG. 12B), A52 (FIG. 12C), benchmark antibody 1 (FIG. 12D), and benchmark antibody 2 (FIG. 12E), in A375 cells endogenously expressing IL13Ra2 and pretreated with human IL 13, as further illustrated in Example 6.

[0023] FIGs. 13A-13E provide exemplary ADC piggy-back assay results of A22 (FIG. 13A), A33 (FIG. 13B), A52 (FIG. 13C), benchmark antibody 1 (FIG. 13D), and benchmark antibody 2 (FIG. 13E), in HEK cells expressing cyno IL13Ra2, as further illustrated in Example 6.

[0024] FIGs. 14A-14E provide exemplary binding results of A22 (FIG. 14A), A33 (FIG. 14B), A52 (FIG. 14C), benchmark antibody 1 (FIG. 14D), and benchmark antibody 2 (FIG. 14E), to human IL13Ral expressed on HEK cells, as further illustrated in Example 5.

[0025] FIGs. 15A-15E provide exemplary ADC piggy-back assay results of A22 (FIG. 15A), A33 (FIG. 15B), A52 (FIG. 15C), benchmark antibody 1 (FIG. 15D), and benchmark antibody 2 (FIG. 15E), in HEK cells expressing human IL13Ral, as further illustrated in Example 6.

[0026] FIGs. 16A-16E provide exemplary SDS-PAGE results of A22 (FIG. 16A), A33 (FIG. 16B), A52 (FIG. 16C), benchmark antibody 1 (FIG. 16D), and benchmark antibody 2 (FIG. 16E), as further illustrated in Example 4.

[0027] FIGs. 17A-17B illustrate analysis results comparing the ECsos between to free IL13Ra2 on A375 cells vs. to IL13Ra2: lL-13 on A375 cells. FIG. 17A plots all ECsos in the y axis, while FIG. 17B plots the ECsos of IL13Ra2 along the y axis and the ECsos of IL13Ra2: lL-13 along the x axis.

[0028] FIG. 18 illustrates analysis results comparing the ECsos between to free human IL13Ra2 on A375 vs. to free cyno IL13Ra2 on cyno IL13Ra2 over-expressing cells.

[0029] FIGs. 19A-19B compares the BmaxS of indicated groups. FIG. 19A illustrates analysis results comparing the BmaxS between to free IL13Ra2 on A375 vs. IL-13 bound IL13Ra2 on A375. FIG. 19B illustrates analysis results comparing the BmaxS between to free human IL13Ra2 on A375 vs. to free cyno IL13Ra2 on cyno IL13Ra2 over-expressing cells.

[0030] FIGs. 20A-20B illustrates analysis results comparing the cytotoxicity ICsos between to free IL13Ra2 on A375 cells vs. to IL13Ra2: lL-13 on A375 cells. FIG. 20A plots all ICsos in the y axis, while FIG. 20B plots the ICsos of IL13Ra2 along the y axis and the ICsos of IL13Ra2: lL-13 along the x axis.

[0031] FIGs. 21A-21B compares cell binding vs. cytotoxicity capability. FIG. 21A illustrates analysis results between the cell binding ECsos vs. the cytotoxicity ICsos, both of which are to the free IL13Ra2 on A375 cells. FIG. 21B illustrates analysis results between the cell binding ECsos vs. the cytotoxicity ICsos, both of which are to the IL 13 bound IL13Ra2 on A375 cells.

[0032] FIGs. 22A-22B illustrate analysis results comparing the ICsos between to free human IL13Ra2 on A375 vs. to free cyno IL13Ra2 on cyno IL13Ra2 over-expressing cells (FIG. 22A), and between the cell binding ECsos vs. the cytotoxicity ICsos, both of which are to free cyno IL13Ra2 on cyno IL13Ra2 over-expressing cells (FIG. 22B).

[0033] FIGs. 23A-23B illustrate analysis results between A375 cell binding ECsos vs. Kd affinity of binding to free human IL13Ra2. FIG. 23A plots both ECsos and Kd in the y axis, while FIG. 23B plots the Kd along the y axis and the ECsos along the x axis.

[0034] FIGs. 24A-24B illustrate analysis results between ECsos of binding to IL13-treated A375 cells vs. Kd affinity of binding to human IL13Ra2:IL13 complex. FIG. 24A plots both ECsos and Kd in the y axis, while FIG. 24B plots the Kd along the y axis and the ECsos along the x axis.

[0035] FIGs. 25A-25B illustrate analysis results between ECsos of binding to cyno IL13Ra2 over-expressed on HEK cells vs. Kd affinity of binding to free cyno IL13Ra2. FIG. 25A plots both ECsos and Kd in the y axis, while FIG. 25B plots the Kd along the y axis and the ECsos along the x axis.5. DETAILED DESCRIPTION

[0036] The present disclosure is based, at least in part, on novel IL13Ra2 binding agents and their properties. Such agents include antibodies (e.g., monospecific or multispecific, including bispecific) that bind to IL13Ra2 (or an IL13Ra2:IL13 complex), including antibodies that bind to human IL13Ra2 (or an IL13Ra2:IL13 complex). In certain aspects, such binding agents are useful in compositions and in methods identifying a cell expressingIL13Ra2, for reducing (including but not limited to abolishing) viability or proliferation of an IL13Ra2-expressing cell, or for killing an IL13Ra2-expressing cell (for example, a cancer cell). In addition, IL13Ra2 binding agents described herein, such as IL13Ra2 binding antibodies (e.g, monospecific or multispecific antibodies, including bispecific antibodies), are useful for the killing and / or removal of tumor cells, inhibiting tumor invasion and metastasis. In further embodiments, the tumor cells express (including overexpress) IL13Ra2. IL13Ra2 binding agents described herein, such as IL13Ra2 binding antibodies (e.g, monospecific or multispecific antibodies, including bispecific antibodies), are useful in compositions and in methods for treating a disease or disorder such as cancer.

[0037] As it would be understood, the section or subsection headings as used herein is for organizational purposes only and are not to be construed as limiting and / or separating the subject matter described.5.1. Definitions

[0038] Techniques and procedures described or referenced herein include those that are generally well understood and / or commonly employed using conventional methodology by those skilled in the art, such as, for example, the widely utilized methodologies described in Sambrook et cd.. Molecular Cloning: A Laboratory Manual (3d ed. 2001); Current Protocols in Molecular Biology (Ausubel et al. eds., 2003); Therapeutic Monoclonal Antibodies: From Bench to Clinic (An ed. 2009); Monoclonal Antibodies: Methods and Protocols (Albitar ed. 2010); and Antibody Engineering Vols 1 and 2 (Kontermann and Diibel eds., 2d ed. 2010). Unless otherwise defined herein, technical and scientific terms used in the present description have the meanings that are commonly understood by those of ordinary skill in the art. For purposes of interpreting this specification, the following description of terms will apply and whenever appropriate, terms used in the singular will also include the plural and vice versa. In the event that any description of a term set forth conflicts with any document incorporated herein by reference, the description of the term set forth below shall control.

[0039] The term “IL13Ra2” refers to a polypeptide (“polypeptide” and “protein” are used interchangeably herein) or any native IL13Ra2 from any vertebrate source, including mammals such as primates (e.g., humans, cynomolgus monkey (cyno)), dogs, and rodents (e.g., mice and rats), unless otherwise indicated.

[0040] An exemplary amino acid sequence of human IL13Ra2 is provided below: MAFVCLAIGCLYTFLISTTFGCTSSSDTEIKVNPPQDFEIVDPGYLGYLYLQWQPPLSL DHFKECTVEYELKYRNIGSETWKTIITKNLHYKDGFDLNKGIEAKIHTLLPWQCTNGSEVQSSWAETTYWISPQGIPETKVQDMDCVYYNWQYLLCSWKPGIGVLLDTNYNLFY WYEGLDHALQCVDYIKADGQNIGCRFPYLEASDYKDFYICVNGSSENKPIRSSYFTF QLQNIVKPLPPVYLTFTRESSCEIKLKWSIPLGPIPARCFDYEIEIREDDTTLVTATVEN ETYTLKTTNETRQLCFVVRSKVNIYCSDDGIWSEWSDKQCWEGEDLSKKTLLRFWL PFGFILILVIFVTGLLLRKPNTYPKMIPEFFCDT (SEQ ID NO:83, UniProt: Q14627). In some embodiments, an exemplary amino acid sequence of human IL13Ra2 is amino acid (aa) 27 to aa 380 of SEQ ID NO: 83. In some embodiments, the extracellular domain (ECD) of human IL13Ra2 is aa 1 to aa 343 of SEQ ID NO:83. In some embodiments, the ECD of human IL13Ra2 is aa 27 to aa 343 of SEQ ID NO:83.

[0041] An exemplary amino acid sequence of cynomolgus monkey (cyno) IL13Ra2 (which is identical to a rhesus macaque IL13Ra2) is provided below:MDF VYL AIRCLCTFLISTTFGYTS S SDTEIKVNPPQDFEIVDPGYLGYLYLQWQPPLSL DNFKECTVEYELKYRNIGSETWTTIITKNLHYKDGFDLNKGIEAKIHTLLPWQCTNGS EVQSSWAEATYWISPQGIPETKVQDMDCVYYNWQYLLCSWKPGIGVLLDTNYNLF YWYEGLDRALQCVDYIKVDGQNIGCRFPYLESSDYKDFYICVNGSSETKPIRSSYFTF QLQNIVKPLPPVCLTCTQESLYEIKLKWSIPLGPIPARCFVYEIEIREDDTTLVTTTVEN ETYTLKITNETRQLCFVVRSKVNIYCSDDGIWSEWSDKQCWEVEELLKKTLLLFLLPF GFILILVIFVTGLLLCKRDSYPKMNFSVIDEDFPYQETWY (SEQ ID NO:84, UniProt: F6Z890). In some embodiments, an exemplary amino acid sequence of cyno / rhesus IL13Ra2 is aa 26 to aa 388 of SEQ ID NO:84. In some embodiments, the extracellular domain (ECD) of cyno / rhesus IL13Ra2 is aa 1 to aa 340 of SEQ ID NO:84. In some embodiments, the ECD of cyno / rhesus IL13Ra2 is aa 26 to aa 340 of SEQ ID NO:84.

[0042] An exemplary amino acid sequence of mouse IL13Ra2 is provided below: MAFVHIRCLCFILLCTITGYSLEIKVNPPQDFEILDPGLLGYLYLQWKPPVVIEKFKGC TLEYELKYRNVDSDSWKTIITRNLIYKDGFDLNKGIEGKIRTHLSEHCTNGSEVQSPW IEASYGISDEGSLETKIQDMKCIYYNWQYLVCSWKPGKTVYSDTNYTMFFWYEGLD HALQCADYLQHDEKNVGCKLSNLDSSDYKDFFICVNGSSKLEPIRSSYTVFQLQNIV KPLPPEFLHISVENSIDIRMKWSTPGGPIPPRCYTYEIVIREDDISWESATDKNDMKLK RRANESEDLCFFVRCKVNIYCADDGIWSEWSEEECWEGYTGPDSKIIFIVPVCLFFIFL LLLLCLIVEKEEPEPTLSLHVDLNKEVCAYEDTLC (SEQ ID NO:85, UniProt: 088786). In some embodiments, an exemplary amino acid sequence of mouse IL13Ra2 is aa 21 to aa 383 of SEQ ID NO:85. In some embodiments, an exemplary amino acid sequence of mouse IL13Ra2 is aa 22 to aa 383 of SEQ ID NO:85. In some embodiments, the ECD of mouse IL13Ra2 is aa 1 to aa 334 of SEQ ID NO:85. In some embodiments, the ECD of mouseIL13Ra2 is aa 21 to aa 334 of SEQ ID NO:85. In some embodiments, the ECD of mouse IL13Ra2 is aa 22 to aa 334 of SEQ ID NO:85. In some embodiments, the ECD of mouse IL13Ra2 is aa 1 to aa 344 of SEQ ID NO:85. In some embodiments, the ECD of mouse IL13Ra2 is aa 21 to aa 344 of SEQ ID NO:85. In some embodiments, the ECD of mouse IL13Ra2 is aa 22 to aa 344 of SEQ ID NO:85.

[0043] An exemplary amino acid sequence of rat IL13Ra2 is provided below: MALMAVNTRCLCLFLLCTITGHSLEIKVNPPQDFEILDPGLLGYLYLQWKPPVVMDN FKECKLEYELKYRNVDSDSWKTIITRNLIYKDGFDLNKGIEGKIRTHLSEHCTNGSEV QSPWTEASYGIADEGSLGTKIQDMKCIYYNWQYLVCSWKPGKTVHSDTNYTMFFW YEGLDHALQCADYLQDNEKNVGCKLSNLDSSDYKDFFIRVNGSSKLEPIRSSYMVFQ LQNIVKPLPPEFLHISVENSIDIRMKWSTPGGPIPPSCYTYEIVVREDDISWESATDKND MKLKRRANESEDLCFFVRCKINIYCADDGIWSEWSEEECWEGYTGPDSKIVFIVPVC LFFIFLLLLLCLIVEKEDPEPTLSLHVDLNKEMYAYEETLC (SEQ ID NO:86, UniProt: Q8VHK6). In some embodiments, an exemplary amino acid sequence of rat IL13Ra2 is aa 24 to aa 385 of SEQ ID NO:86. In some embodiments, the ECD of rat IL13Ra2 is aa 1 to aa 336 of SEQ ID NO:86. In some embodiments, the ECD of rat IL13Ra2 is aa 24 to aa 336 of SEQ ID NO:86.

[0044] IL13Ra2 is a single-pass type I transmembrane protein comprising three fibronectin type III (FNIII)-like domains (101, 97, and 94 aa), a single transmembrane (TM) domain (20 aa), and a short cytoplasmic domain (17 aa). There is one natural variant W111R. Four N- linked glycosylation sites are predicted, including: N115, N215, N290, and N299. IL13Ra2 is primarily tumor-restricted with protein expression in normal spermatocytes. It is also upregulated in malignant melanomas, malignant gliomas, pancreatic, ovarian, breast, liver, head and neck, and renal cancers. Its soluble form is detected in human and mouse serum / plasma (ng / mL), but conflicting reports are found on detection in human. Its soluble form is produced in mice by alternative splicing and MMP-8 cleavage, while in humans only by MMP-8 cleavage. IL13Ra2 is a high affinity (fM) Th2 cytokine receptor for IL-13, has been thought to be a decoy receptor, inhibits IL- 13 signaling, regulates serum and tissues levels of IL-13, and can mediate biological effects such as tumor proliferation, cell survival, cell adhesion and metastasis. The classic pathway for IL- 13 activation is JAK / STAT via binding heterodimer of IL-13Ral and IL-4Ra (Type II complex), not IL-13Ra2. In other words, IL-13Ra2 binds IL-13 with extremely high affinity (< 10'15M), although it does not bind IL-4. It can act as a negative regulator of IL-4, but not IL- 13 induced signaling through the Type II IL-4R, but unclear how.

[0045] In some embodiments, the term IL13Ra2 as used herein refers to an IL13Ra2 epitope. In further embodiments, the term IL13Ra2 as used herein refers to an epitope of the ECD of IL13Ra2. In some embodiments, the term IL13Ra2 as used herein refers to a complex comprising IL13Ra2 and IL13. In further embodiments, the term IL13Ra2 as used herein refers to a complex comprising the ECD of IL13Ra2 and IL13. In yet further embodiments, the term IL13Ra2 as used herein refers to an epitope of a complex comprising the ECD of IL13Ra2 and IL13.

[0046] IL-13Ral belongs to the same family as IL-13Ra2, but shares a low sequence identity (20%). An exemplary amino acid sequence of human IL13Ral is provided below: MEWPARLCGLWALLLCAGGGGGGGGAAPTETQPPVTNLSVSVENLCTVIWTWNPP EGASSNCSLWYFSHFGDKQDKKIAPETRRSIEVPLNERICLQVGSQCSTNESEKPSILV EKCISPPEGDPESAVTELQCIWHNLSYMKCSWLPGRNTSPDTNYTLYYWHRSLEKIH QCENIFREGQYFGCSFDLTKVKDSSFEQHSVQIMVKDNAGKIKPSFNIVPLTSRVKPD PPHIKNLSFHNDDLYVQWENPQNFISRCLFYEVEVNNSQTETHNVFYVQEAKCENPE FERNVENTSCFMVPGVLPDTLNTVRIRVKTNKLCYEDDKLWSNWSQEMSIGKKRNS TLYITMLLIVPVIVAGAIIVLLLYLKRLKIIIFPPIPDPGKIFKEMFGDQNDDTLHWKKY DIYEKQTKEETDSVVLIENLKKASQ (SEQ ID NO:87, UniProt: P78552). In some embodiments, an exemplary amino acid sequence of human IL13Ral is aa 22 to aa 427 of SEQ ID NO:87. In some embodiments, an exemplary amino acid sequence of the ECD of human IL13Ral is aa 1 to aa 343 of SEQ ID NO:87. In some embodiments, an exemplary amino acid sequence of the ECD of human IL13Ral is aa 22 to aa 343 of SEQ ID NO:87. In some embodiments, the term IL13Ral as used herein refers to an IL13Ral epitope. In yet further embodiments, the term IL13Ral as used herein refers to the ECD of IL13Ral. In yet further embodiments, the term IL13Ral as used herein refers to an epitope of the ECD of IL13Ral.

[0047] An exemplary amino acid sequence of human IL 13 is provided below: MHPLLNPLLLALGLMALLLTTVIALTCLGGFASPGPVPPSTALRELIEELVNITQNQK APLCNGSMVWSINLTAGMYCAALESLINVSGCSAIEKTQRMLSGFCPHKVSAGQFSS LHVRDTKIEVAQFVKDLLLHLKKLFREGRFN (SEQ ID NO:88, UniProt: P35225). In some embodiments, an exemplary amino acid sequence of human IL13 is aa 25 to aa 146 of SEQ ID NO:88. In some embodiments, an exemplary amino acid sequence of human IL13 is provided below: MALLLTTVIALTCLGGFASPGPVPPSTALRELIEELVNITQNQKAPLCNGSMVWSINLTAGMYCAALESLINVSGCSAIEKTQRMLSGFCPHKVSAGQFSSLHVRDTKIEVAQFV KDLLLHLKKLFREGRFN (SEQ ID NO:89, GenBank: AAK53823.1).

[0048] An exemplary amino acid sequence of cyno IL 13 is provided below: MALLLTMVIALTCLGGFASPSPVPPSTALKELIEELVNITQNQKAPLCNGSMVWSINL T AGVYC AALESLINVSGC S AIEKTQRMLNGFCPHKVS AGQF S SLRVRDTKIEVAQF V KDLLVHLKKLFREGQFN (SEQ ID NO:90, GenBank: BG75889.1).

[0049] As used herein, the term “binding agent” or a grammatical equivalent thereof refers to a molecule (e.g., antibody) with one or more antigen-binding sites that binds an antigen. In some embodiments, an IL13Ra2 binding agent as described herein is an antibody (including an antibody fragment, such as an antigen-binding fragment or an epitope-binding fragment) or other peptide-based molecule as well as a conjugate of an antibody, antibody fragment, or peptide-based molecule (e.g., an antibody-drug conjugate) that binds to IL13Ra2, such as human IL13Ra2.

[0050] The terms “antibody,” “immunoglobulin,” and “Ig” are used interchangeably herein, and are used in the broadest sense and specifically cover, for example polyclonal antibodies, monoclonal antibodies (including agonist, antagonist, neutralizing antibodies, full-length monoclonal antibodies), antibody compositions with polyepitopic or monoepitopic specificity, recombinantly produced antibodies, single domain (e.g., VHH) antibodies, monospecific antibodies, multispecific antibodies (including bispecific antibodies), synthetic antibodies, chimeric antibodies, humanized antibodies, or human versions of antibodies having full-length heavy and / or light chains. VHH as used herein refers to a domain antibody derived from a variable region of a heavy chain only antibody. Exemplary single domain antibodies include, but are not limited to, antibodies naturally devoid of light chains such as those from Camelidae species (e.g., llama), single domain antibodies derived from conventional 4-chain antibodies, engineered antibodies and single domain scaffolds other than those derived from antibodies. Single domain antibodies may be derived from any species including, but not limited to mouse, human, camel, llama, goat, rabbit, and bovine. VHH can also be derived from other species besides Camelidae that may produce heavy chain antibodies naturally devoid of light chain. Antibodies also include antibody fragments (and / or polypeptides that comprise antibody fragments) that retain IL13Ra2 binding characteristics. Non-limiting examples of antibody fragments include antigen-binding regions and / or effector regions of the antibody, e.g., Fab, Fab’, F(ab’)2, Fv, scFv, (scFv)2, single chain antibody molecule, dual variable domain antibody, single variable domain, linear antibody, V region, a multispecific antibody formed from antibody fragments, F(ab)2, Fd, Fc,diabody, di-diabody, disulfide-linked Fvs (dsFv), single-domain antibody (e.g., nanobody) or other fragments (e.g., fragments consisting of the variable regions of the heavy and light chains that are non-covalently coupled). In general terms, a variable (V) region domain may be any suitable arrangement of immunoglobulin heavy (VH) and / or light (VL) variable domains. For example, antibodies also include tetrameric antibodies comprising two heavy chain and two light chain molecules, an antibody light chain monomer, and an antibody heavy chain monomer. Thus, for example, the V region domain may be dimeric and contain VHH-VHH, VH-VH, VH-VL, or VL-VL dimers that bind IL13Ra2. If desired, the VH and VL may be covalently coupled either directly or through a linker to form a single chain Fv (scFv). For ease of reference, scFv proteins are referred to herein as included in the category “antibody fragments.” Another form of an antibody fragment is a peptide comprising one or more complementarity determining regions (CDRs) of an antibody. CDRs (also termed “minimal recognition units” or “hypervariable regions”) can be obtained by constructing polynucleotides that encode one or more CDRs of interest. Such polynucleotides are prepared, for example, by using the polymerase chain reaction to synthesize the variable region using mRNA of antibody-producing cells as a template (see, for example, Larrick et al., Methods: A Companion to Methods in Enzymology, 2: 106 (1991); Courtenay-Luck, “Genetic Manipulation of Monoclonal Antibodies,” in Monoclonal Antibodies Production, Engineering and Clinical Application, Ritter et al. (eds.), page 166, Cambridge University Press (1995); and Ward et al, “Genetic Manipulation and Expression of Antibodies,” in Monoclonal Antibodies: Principles and Applications, Birch et al., (eds.), page 137, Wiley- Liss, Inc. (1995)). Antibody fragments may be incorporated, for example, into single domain antibodies, maxibodies, minibodies, intrabodies, diabodies, triabodies, tetrabodies, variable domains of new antigen receptors (v-NAR), and bis-single chain Fv regions (see, e.g., Hollinger and Hudson, Nature Biotechnology, 23(9): 1126-1136, 2005). In some embodiments, antibodies comprising a VH and / or VL further contain a light chain and / or a heavy chain constant region, such as one or more constant regions, including one or more IgGl, IgG2, IgG3 and / or IgG4 constant regions. In some embodiments, antibodies can include epitope-binding fragments of any of the above. The antibodies described herein can be of any class (e.g., IgG, IgE, IgM, IgD, and IgA) or any subclass (e.g., IgGl, IgG2, IgG3, IgG4, IgAl, and IgA2) of immunoglobulin molecule.

[0051] The term “monospecific” when used in reference to a binding agent (e.g. , an antibody) as used herein denotes a binding agent that has one or more binding sites each of which binds to the same epitope of the same antigen.

[0052] The term “multispecific” when used in reference to a binding agent (e.g., an antibody) means that the binding agent is able to specifically bind to at least two distinct epitopes, for example two binding sites each formed by a pair of an antibody heavy chain variable domain (VH) and an antibody light chain variable domain (VL) or each formed by a pair of VHH domains binding to different antigens or to different epitopes on the same antigen. Such a bispecific binding agent (e.g., an antibody) may have a 1+1 format (comprising one binding site for a first antigen or epitope and one binding site for a second antigen or epitope). Other bispecific binding agent (e.g., an antibody) formats may be 2+1 or 1+2 formats (comprising two binding sites for a first antigen or epitope and one binding site for a second antigen or epitope) or 2+2 format (comprising two binding sites for a first antigen or epitope and two binding sites for a second antigen or epitope). When a bispecific binding agent (e.g., an antibody) comprises two antigen-binding sites, each may bind to a different epitope. Such a bispecific binding agent (e.g., an antibody) may bind to two different epitopes on the same antigen (e.g., epitopes on IL13Ra2).

[0053] The terms “identical” or percent “identity” in the context of two or more nucleic acids or polypeptides, refer to two or more sequences or subsequences that are the same or have a specified percentage of nucleotides or amino acid residues that are the same, when compared and aligned (introducing gaps, if necessary) for maximum correspondence, not considering any conservative amino acid substitutions as part of the sequence identity. The percent identity can be measured using sequence comparison software or algorithms or by visual inspection. Various algorithms and software that can be used to obtain alignments of amino acid or nucleotide sequences are well-known in the art. These include, but are not limited to, BLAST, ALIGN, Megalign, BestFit, GCG Wisconsin Package, and variants thereof. In some embodiments, two nucleic acids or polypeptides are substantially identical, meaning they have at least 70%, at least 75%, at least 80%, at least 85%, or at least 90%, and in some embodiments at least 95%, 96%, 97%, 98%, or 99% nucleotide or amino acid residue identity, when compared and aligned for maximum correspondence, as measured using a sequence comparison algorithm or by visual inspection. In some embodiments, identity exists over a region of the amino acid sequences that is at least about 10 residues, at least about 20 residues, at least about 40-60 residues, at least about 60-80 residues in length or any integral value there between. In some embodiments, identity exists over a longer region than 60-80 residues, such as at least about 80-100 residues, and in some embodiments the sequences are substantially identical over the full length of the sequences being compared, such as the coding region of a target protein or an antibody. In someembodiments, identity exists over a region of the nucleotide sequences that is at least about 10 bases, at least about 20 bases, at least about 40-60 bases, at least about 60-80 bases in length or any integral value there between. In some embodiments, identity exists over a longer region than 60-80 bases, such as at least about 80-1000 bases or more, and in some embodiments the sequences are substantially identical over the full-length of the sequences being compared, such as a nucleotide sequence encoding a protein of interest.

[0054] A “conservative amino acid substitution” is one in which one amino acid residue is replaced with another amino acid residue having a side chain with similar chemical characteristics. Families of amino acid residues having similar side chains have been generally defined in the art, including basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). For example, substitution of a phenylalanine for a tyrosine is a conservative substitution. Generally, conservative substitutions in the sequences of the polypeptides, soluble proteins, and / or antibodies of the disclosure do not abrogate the binding of the polypeptide, soluble protein, or antibody containing the amino acid sequence, to the target binding site. Methods of identifying amino acid conservative substitutions which do not eliminate binding are well-known in the art.

[0055] The term “polypeptide” refers to polymers of amino acids of any length. The polymer can be linear or branched, it can comprise modified amino acids, and it can include (e.g., be interrupted by) non-amino acids. The terms also encompass an amino acid polymer that has been modified naturally or by intervention; for example, disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation or modification, such as linkage to or conjugation with (directly or indirectly) a moiety such as a labeling component or a drug (e.g., toxin). Also included within the definition are, for example, polypeptides containing one or more analogs of an amino acid (including, for example, unnatural amino acids), as well as other modifications known in the art. It is understood that, because the polypeptides of this disclosure can be based upon antibodies or other members of the immunoglobulin superfamily, in some embodiments, the polypeptides can occur as single chains or dimers of single chains.

[0056] As used herein, an “antigen” is a moiety or molecule that contains an epitope to which a binding agent (e.g., an antibody) can bind. As such, an antigen can be bound by anantibody. In some embodiments, the antigen, to which a binding agent (e.g., an antibody) described herein binds, is IL13Ra2 (e.g., human IL13Ra2), or a fragment thereof, including a fragment that comprises one or more domains of IL13Ra2.

[0057] As used herein, an “epitope” is a term in the art and refers to a localized region of an antigen to which an antibody can bind. An epitope can be a linear epitope or a conformational, non-linear, or discontinuous, epitope. In the case of a polypeptide antigen, for example, an epitope can be contiguous amino acids of the polypeptide (a “linear” epitope) or an epitope can comprise amino acids from two or more non-contiguous regions of the polypeptide (a “conformational,” “non-linear” or “discontinuous” epitope), e.g., human IL13Ra2. It will be appreciated by one of skill in the art that, in general, a linear epitope may or may not be dependent on secondary, tertiary, or quaternary structure. For example, in some embodiments, an antibody binds to a group of amino acids regardless of whether they are folded in a natural three-dimensional protein structure. In other embodiments, an antibody requires amino acid residues making up the epitope to exhibit a particular conformation (e.g., bend, twist, turn or fold) in order to recognize and bind the epitope.

[0058] An antibody binds “an epitope” or “essentially the same epitope” or “the same epitope” as a reference antibody, when the two antibodies recognize identical, overlapping or adjacent epitopes in a three-dimensional space. The most widely used and rapid methods for determining whether two antibodies bind to identical, overlapping or adjacent epitopes in a three-dimensional space are competition assays, which can be configured in a number of different formats, for example, using either labeled antigen or labeled antibody. In some assays, the antigen is immobilized on a 96-well plate, or expressed on a cell surface, and the ability of unlabeled antibodies to block the binding of labeled antibodies is measured using radioactive, fluorescent or enzyme labels.

[0059] “Epitope binning” is the process of grouping antibodies based on the epitopes they recognize. More particularly, epitope binning comprises methods and systems for discriminating the epitope recognition properties of different antibodies, using competition assays combined with computational processes for clustering antibodies based on their epitope recognition properties and identifying antibodies having distinct binding specificities.

[0060] As used herein, the terms “specifically binds,” “specifically recognizes,” “immunospecifically binds,” “selectively binds,” “immunospecifically recognizes” and “immunospecific” are analogous terms in the context of antibodies and refer to molecules that bind to an antigen (e.g., epitope) as such binding is understood by one skilled in the art. In some embodiments, “specifically binds” means, for instance that a polypeptide ormolecule interacts more frequently, more rapidly, with greater duration, with greater affinity, or with some combination of the above to the epitope, protein, or target molecule than with alternative substances, including related and unrelated proteins. For example, a molecule that specifically binds to an antigen may bind to other peptides or polypeptides, generally with lower affinity as determined by, e.g., immunoassays, BIACORE™, KinExA 3000 instrument (Sapidyne Instruments, Boise, ID), the OctetQK384 system (ForteBio, Menlo Park, CA), or other assays known in the art. In some embodiments, an antibody or antigen-binding domain binds to or specifically binds to an antigen when it binds to the antigen with higher affinity than to any cross-reactive antigen as determined using experimental techniques, such as radioimmunoassays (RIAs) and enzyme linked immunosorbent assays (ELISAs). Typically a specific or selective reaction will be at least twice background signal or noise and may be more than 10 times background. See, e.g., Fundamental Immunology 332-36 (Paul ed., 2d ed. 1989) for a discussion regarding binding specificity. In some embodiments, the extent of binding of an antibody or antigen-binding domain to a “non-targef ’ protein is less than about 10% of the binding of the antibody or antigen-binding domain to its particular target antigen, for example, as determined by fluorescence activated cell sorting (FACS) analysis or RIAs. In some embodiments, molecules that specifically bind to an antigen bind to the antigen with a Ka that is at least 2 logs, 2.5 logs, 3 logs, 4 logs or greater than the Ka when the molecules bind to another antigen. In some embodiments, molecules that specifically bind to an antigen do not cross react with other proteins. In another specific embodiment, molecules that specifically bind to an antigen do not cross react with other non-IL13Ra2 proteins. In some embodiments “specifically binds” means, for instance, that a polypeptide or molecule binds a protein or target with a KD of about 0. ImM or less, but more usually less than about 1 pM. In some embodiments, “specifically binds” means that a polypeptide or molecule binds a target with a KD of at least about 0.1 pM or less, at least about 0.01 pM or less, or at least about InM or less. Because of the sequence identity between homologous proteins in different species, specific binding can include a polypeptide or molecule that recognizes a protein or target in more than one species. Likewise, because of homology within certain regions of polypeptide sequences of different proteins, specific binding can include a polypeptide or molecule that recognizes more than one protein or target. It is understood that, in some embodiments, a polypeptide or molecule that specifically binds a first target may or may not specifically bind a second target. As such, “specific binding” does not necessarily require (although it can include) exclusive binding, e.g., binding to a single target. Thus, a polypeptide or molecule can, in some embodiments, specifically bind more than one target. In some embodiments,multiple targets can be bound by the same antigen-binding site on the polypeptide or molecule. For example, an antibody can, in certain instances, comprise two identical antigenbinding sites, each of which specifically binds the same epitope on two or more proteins. In certain alternative embodiments, an antibody can be bispecific and comprise at least two antigen-binding sites with differing specificities. Generally, but not necessarily, reference to “binding” means “specific binding”.

[0061] “Binding affinity” generally refers to the strength of the sum total of noncovalent interactions between a single binding site of a molecule (e.g., a binding agent such as an antibody) and its binding partner (e.g., an antigen such as IL13Ra2). Unless indicated otherwise, as used herein, “binding affinity” refers to intrinsic binding affinity which reflects a 1 : 1 interaction between members of a binding pair (e.g., antibody and antigen). The affinity of a binding molecule X for its binding partner Y can generally be represented by the dissociation constant (KD). Affinity can be measured by common methods known in the art, including those described herein. Low-affinity antibodies generally bind antigen slowly and tend to dissociate readily, whereas high-affinity antibodies generally bind antigen faster and tend to remain bound longer. A variety of methods of measuring binding affinity are known in the art, any of which can be used for purposes of the present disclosure. In one embodiment, the “KD” or “KD value” may be measured by biolayer interferometry (BLI) using, for example, the OctetQK384 system (ForteBio, Menlo Park, CA). Alternatively, the KD may also be measured in a radiolabeled antigen-binding assay (RIA), for example, performed with the Fab version of an antibody of interest and its antigen (Chen, et al., (1999) J. Mol Biol 293:865-881) or using surface plasmon resonance (SPR) assays by BIACORE™, using, for example, a BIACORE™-2000 or a BIACORE™-3000 (BIACORE™, Inc., Piscataway, NJ). An “on-rate” or “rate of association” or “association rate” or “kon,” as well as an “off-rate” or “rate of dissociation” or “dissociation rate” or “kOff,” can also be determined with the same SPR or BLI techniques described above using, for example, the OctetQK384 system (ForteBio, Menlo Park, CA) or a BIACORE™-2000 or a BIACORE™- 3000 (BIACORE™, Inc., Piscataway, NJ), respectively.

[0062] The term “compete” or any grammatical variation thereof when used in the context of IL13Ra2 binding agents (e.g., antibodies) means binding agents that compete for the same epitope or binding site on a target, which includes competition between such binding agents as determined by an assay in which the binding agent under study prevents or inhibits the specific binding of a reference molecule (e.g., a reference ligand, or reference antigenbinding protein, such as a reference antibody) to a common antigen (e.g., IL13Ra2).Numerous types of competitive binding assays can be used to determine if a test binding agent competes with a reference molecule for binding to IL13Ra2 (e.g., human IL13Ra2). Examples of assays that can be employed include solid phase direct or indirect radioimmunoassay (RIA); solid phase direct or indirect enzyme immunoassay (EIA), sandwich competition assay (see, e.g., Stahli et al., (1983) Methods in Enzymology 9:242- 253); solid phase direct biotin-avidin EIA (see, e.g., Kirkland et al., (1986) J. Immunol. 137:3614-3619 or Cheung, et al, (1990) Virology 176:546-552); solid phase direct labeled assay; solid phase direct labeled sandwich assay (see, e.g., Harlow and Lane, (1988) Antibodies, A Laboratory Manual, Cold Spring Harbor Press); solid phase direct label RIA using 1-125 label (see, e.g., Morel et al., (1988) Molec. Immunol. 25:7-15); and direct labeled RIA (Moldenhauer et al., (1990) Scand. J. Immunol. 32:77-82). Typically, such an assay involves the use of a purified antigen (e.g., IL13Ra2, such as human IL13Ra2) bound to a solid surface or cells bearing either of an unlabeled test antigen-binding protein (e.g., test IL13Ra2 antibody) or a labeled reference antigen-binding protein (e.g., reference IL13Ra2 antibody). Competitive inhibition may be measured by determining the amount of label bound to the solid surface or cells in the presence of the test antigen-binding protein. Usually, the test antigen-binding protein is present in excess. Antibodies identified by competition assay (competing antibodies) include antibodies binding to the same epitope as the reference antibody and / or antibodies binding to an adjacent epitope sufficiently proximal to the epitope bound by the reference for antibodies steric hindrance to occur (e.g., similar epitope or overlapping epitope). Usually, when a competing antibody is present in excess, it will inhibit specific binding of a reference antibody to a common antigen by at least 20%, for example, at least 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or 75%. In some instance, binding is inhibited by at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or more.

[0063] As used herein, the term “constant region” or “constant domain” is a well-known antibody term of art and refers to an antibody portion, for example, a carboxyl terminal portion of a light and / or heavy chain which is not directly involved in binding of an antibody to an antigen but which can exhibit various effector functions, such as interaction with an Fc receptor. The term includes the portion of an immunoglobulin molecule having a generally more conserved amino acid sequence relative to an immunoglobulin variable domain.

[0064] Antibody “effector functions” refer to those biological activities attributable to the Fc region (e.g., a native sequence Fc region or amino acid sequence variant Fc region) of an antibody, and vary with the antibody isotype. Examples of antibody effector functionsinclude: Clq binding and complement dependent cytotoxicity; Fc receptor binding; antibodydependent cell-mediated cytotoxicity (ADCC); phagocytosis; down regulation of cell surface receptors (e.g., B cell receptor); and B cell activation.

[0065] The term “Fc region” herein is used to define a C-terminal region of an immunoglobulin heavy chain, including, for example, native sequence Fc regions, recombinant Fc regions, and variant Fc regions. Although the boundaries of the Fc region of an immunoglobulin heavy chain might vary, the human IgG heavy chain Fc region is often defined to stretch from an amino acid residue at position Cys226 (according to the EU numbering system), or from Pro230 (according to the EU numbering system), to the carboxyl-terminus thereof. The C-terminal lysine (residue 447 according to the EU numbering system) of the Fc region may be removed, for example, during production or purification of the antibody, or by recombinantly engineering the nucleic acid encoding a heavy chain of the antibody. An exemplary Fc region sequence is provided below (CH2 domain = bold text; CH3 domain = underline text):CPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVD GVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIE KTISKAKGOPREPQVYTLPPSREEMTKNOVSLTCLVKGFYPSDIAVEWESNGOPENN YKTTPPVLDSDGSFFLYSKLTVDKSRWOOGNVFSCSVMHEALHNHYTQKSLSLSPG K (SEP ID NO:91)

[0066] A “functional Fc region” possesses an “effector function” of a native sequence Fc region. Exemplary “effector functions” include Clq binding; complement dependent cytotoxicity (CDC); Fc receptor binding; antibody-dependent cell-mediated cytotoxicity (ADCC); phagocytosis (such as antibody-dependent cellular phagocytosis, z.e., ADCP); down regulation of cell surface receptors (e.g., B cell receptor; BCR), etc. Such effector functions generally require the Fc region to be combined with a binding region or binding domain (e.g., an antibody variable region or domain) and can be assessed using various assays as disclosed.

[0067] A “native sequence Fc region” comprises an amino acid sequence identical to the amino acid sequence of an Fc region found in nature, and not manipulated, modified, and / or changed (e.g., isolated, purified, selected, including or combining with other sequences such as variable region sequences) by a human. Native sequence human Fc regions include a native sequence human IgGl Fc region (non- A and A allotypes); native sequence human IgG2 Fc region; native sequence human IgG3 Fc region; and native sequence human IgG4 Fc region as well as naturally occurring variants thereof.

[0068] A “variant Fc region” comprises an amino acid sequence which differs from that of a native sequence Fc region by virtue of at least one amino acid modification (e.g., substituting, addition, or deletion), preferably one or more amino acid substitution(s). In some embodiments, the variant Fc region has at least one amino acid substitution compared to a native sequence Fc region or to the Fc region of a parent polypeptide, for example, from about one to about ten amino acid substitutions, and preferably from about one to about five amino acid substitutions in a native sequence Fc region or in the Fc region of the parent polypeptide. The variant Fc region described herein can possess at least about 80% homology with a native sequence Fc region and / or with an Fc region of a parent polypeptide, or at least about 90% homology therewith, for example, at least about 95% homology therewith. The variant Fc region herein described herein may have a loss of an effector function (e.g., silent Fc). An exemplary variant Fc region (“silent Fc”) sequence is provided below (CH2 domain = bold text with amino acid changes underlined; CH3 domain = underline text):CPPCPAPEAAGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVD GVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALKAPIE KTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENN YKTTPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPG K (SEQ ID NO: 92).

[0069] As used herein, the term “heavy chain” when used in reference to an antibody refers to a polypeptide chain of about 50-70 kDa, wherein the amino-terminal portion includes a variable region of about 120 to 130 or more amino acids, and a carboxy -terminal portion includes one or more constant regions. The “heavy chain” can refer to any distinct types, e.g., for example, alpha (a), delta (5), epsilon (a), gamma (y) and mu (p), based on the amino acid sequence of the constant domain, which give rise to IgA, IgD, IgE, IgG and IgM classes of antibodies, respectively, including subclasses of IgG, e.g., IgGl, IgG2, IgG3 and IgG4.

[0070] As used herein, the term “light chain” when used in reference to an antibody can refer to a polypeptide chain of about 25 kDa, wherein the amino-terminal portion includes a variable region of about 100 to about 110 or more amino acids, and a carboxy -terminal portion includes a constant region. The approximate length of a light chain is 211 to 217 amino acids. There are two distinct types, e.g., kappa (K) or lambda (X) based on the amino acid sequence of the constant domains. Light chain amino acid sequences are well known in the art.

[0071] The terms “antigen-binding fragment,” “antigen-binding domain,” “antigen-binding region,” and similar terms refer to that portion of an antibody, which comprises the amino acid residues that interact with an antigen and confer on the binding fragment, domain, or region its specificity and affinity for the antigen (e.g., the CDRs). “Antigen-binding fragment” as used herein includes “antibody fragment,” which comprises a portion of an antibody including one or more CDRs, such as the antigen-binding or variable region of the antibody.

[0072] Antibodies described herein include, but are not limited to, synthetic antibodies, monoclonal antibodies, recombinantly produced antibodies, multispecific antibodies (e.g., bispecific antibodies), human antibodies, humanized antibodies, chimeric antibodies, intrabodies, single-chain Fvs (scFv) (e.g., including monospecific, bispecific, etc.), camelized antibodies, Fab fragments, F(ab’) fragments, disulfide-linked Fvs (sdFv), anti -idiotypic (anti- id) antibodies, and epitope-binding fragments of any of the above.

[0073] In some embodiments, antibodies described herein include immunoglobulin molecules and immunologically active portions of immunoglobulin molecules, including molecules that contain one or more antigen-binding sites that bind to an IL13Ra2 antigen.

[0074] Antibodies can be of any type (e.g., IgG, IgE, IgM, IgD, IgA or IgY), any class (e.g., IgGl, IgG2, IgG3, IgG4, IgAl or IgA2), or any subclass (e.g., IgG2a or IgG2b) of immunoglobulin molecule. In some embodiments, antibodies described herein are IgG antibodies (e.g., human IgG), or a class (e.g., human IgGl, IgG2, IgG3 or IgG4) or a subclass thereof.

[0075] In some embodiments, an antibody is a 4-chain antibody unit comprising two heavy (H) chain / light (L) chain pairs. In further embodiments, the amino acid sequences of the H chains are identical and the amino acid sequences of the L chains are identical. In other embodiments, the amino acid sequences of the H chains are different from each other. Additionally or alternatively, the amino acid sequences of the L chains are different from each other. For example, an antibody comprises a first H / L chain pair and a second H / L chain pair, wherein the first H / L chain pair binds to an IL13Ra2 antigen and the second H / L chain pair binds to another IL13Ra2 antigen or a non-IL13Ra2 antigen. In some embodiments, an antibody is a 2-chain antibody unit comprising a VHH-VHH pair. In further embodiments, the amino acid sequences of the VHH are identical. In other embodiments, the amino acid sequence of the VHH are different from each other. For example, an antibody comprises a first VHH and a second VHH, wherein the first VHH binds to an IL13Ra2 antigen and the second VHH binds to another IL13Ra2 antigen or a non-IL13Ra2 antigen. Insome embodiments, the H and / or L chains comprise constant regions, for example, human constant regions. In some embodiments, the L chain constant region of such antibodies is a kappa or lambda light chain constant region, for example, a human kappa or lambda light chain constant region. In some embodiments, the H chain constant region of such antibodies comprises a gamma heavy chain constant region, for example, a human gamma heavy chain constant region. In some embodiments, such antibodies comprise IgG constant regions, for example, human IgG constant regions (e.g., IgGl, IgG2, IgG3, and / or IgG4 constant regions).

[0076] An antibody or fragment thereof may preferentially bind to IL13Ra2 (or an IL13Ra2:IL13 complex), such as human IL13Ra2, meaning that the antibody or fragment thereof binds IL13Ra2 with greater affinity than it binds to a control protein (e.g., unrelated control proteins such as hen egg white lysozyme) and / or binds human IL13Ra2 with greater affinity than it binds to an unrelated control protein. For example, the antibody or fragment thereof may specifically recognize and bind IL13Ra2 or a portion thereof. “Specific binding” means that the antibody or fragment thereof binds to IL13Ra2 with an affinity that is at least 5, 10, 15, 20, 25, 50, 100, 250, 500, 1000, or 10,000 times greater than the affinity for an unrelated control protein (e.g., hen egg white lysozyme). In some embodiments, the antibody or fragment thereof may bind IL13Ra2 substantially exclusively (e.g, is able to distinguish IL13Ra2 from other known polypeptides, for example, by virtue of measurable differences in binding affinity). In some embodiments, an IL13Ra2 binding agent (e.g, an antibody) may react with IL13Ra2 sequences other than human IL13Ra2 sequences (e.g., cynomolgus monkey IL13Ra2 sequences). In other embodiments, an IL13Ra2 binding agent (e.g., an antibody) does not react with non-human (such as cynomolgus monkey).

[0077] The term “variable region” or “variable domain” refers to a portion of the light or heavy chains of an antibody that is generally located at the amino-terminal of the light or heavy chain, has a length of about 120 to 130 amino acids in the heavy chain and about 100 to 110 amino acids in the light chain, and is used in the binding and specificity of each particular antibody for its particular antigen. The variable region of the heavy chain may be referred to as “VH.” The variable region of the light chain may be referred to as “VL.” The term “variable” refers to the fact that certain segments of the variable regions differ extensively in sequence among antibodies. The V region mediates antigen binding and defines specificity of a particular antibody for its particular antigen. However, the variability is not evenly distributed across the 110-amino acid span of the variable regions. Instead, the V regions consist of less variable (e.g., relatively invariant) stretches called framework regions (FRs) of about 15-30 amino acids separated by shorter regions of greater variability(e.g., extreme variability) called “hypervariable regions” or alternatively called “complementarity determining regions (CDRs).” The variable regions of heavy and light chains each comprise four frameworks (FR1, FR2, FR3 and FR4), largely adopting a P sheet configuration, connected by three hypervariable regions, which form loops connecting, and in some cases forming part of, the P sheet structure. The hypervariable regions in each chain are held together in close proximity by the frameworks and, with the hypervariable regions from the other chain, contribute to the formation of the antigen-binding site of antibodies (see, e.g., Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, MD, (1991)). The constant regions are not involved directly in binding an antibody to an antigen, but exhibit various effector functions, such as participation of the antibody in antibody dependent cellular cytotoxicity (ADCC) and complement dependent cytotoxicity (CDC). The variable regions differ extensively in sequence between different antibodies. The variability in sequence is concentrated in the CDRs while the less variable portions in the variable region are referred to as framework regions (FR). The CDRs of the light and heavy chains are primarily responsible for the interaction of the antibody with its antigen. In specific embodiments, the variable region is a human variable region.

[0078] The term “hypervariable region,” “HVR,” “HV,” “complementarity determining region,” or “CDR” when used herein refers to the regions of an antibody variable region that are hypervariable in sequence and / or form structurally defined loops. Generally, antibodies comprise six hypervariable regions: three in the VH (Hl or VH CDR1, H2 or VH CDR2, and H3 or VH CDR3), and three in the VL (LI or VL CDR1, L2 or VL CDR2, and L3 or VL CDR3). A number of hypervariable region delineations are in use and are encompassed herein. The Kabat CDRs are based on sequence variability and are the most commonly used (see, e.g., Kabat et al. , Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, MD. (1991)). Chothia refers instead to the location of the structural loops (see, e.g., Chothia and Lesk, J. Mol. Biol. 196:901-917 (1987)). The end of the Chothia CDR-H1 loop when numbered using the Kabat numbering convention varies between H32 and H34 depending on the length of the loop (this is because the Kabat numbering scheme places the insertions at H35A and H35B; if neither 35 A nor 35B is present, the loop ends at 32; if only 35A is present, the loop ends at 33; if both 35A and 35B are present, the loop ends at 34). The AbM hypervariable regions represent a compromise between the Kabat CDRs and Chothia structural loops, and are used by Oxford Molecular’s AbM antibody modeling software (see, e.g., Martin, in Antibody Engineering,Vol. 2, Chapter 3, Springer Verlag). The “contact” hypervariable regions are based on an analysis of the available complex crystal structures. The residues from each of these hypervariable regions or CDRs are noted below.

[0079] A universal numbering system has been developed and widely adopted, ImMunoGeneTics (IMGT®) Information System (Lefranc el al.. Dev. Comp. Immunol. 27(l):55-77 (2003)). IMGT is an integrated information system specializing in immunoglobulins (IG), T cell receptors (TR) and major histocompatibility complex (MHC) of human and other vertebrates. Herein, the CDRs are referred to in terms of both the amino acid sequence and the location within the light or heavy chain. As the “location” of the CDRs within the structure of the immunoglobulin variable domain is conserved between species and present in structures called loops, by using numbering systems that align variable domain sequences according to structural features, CDR and framework residues and are readily identified. This information can be used in grafting and replacement of CDR residues from immunoglobulins of one species into an acceptor framework from, typically, a human antibody. An additional numbering system (AHon) has been developed by Honegger and Pliickthun, J. Mol. Biol. 309: 657-670 (2001). Correspondence between the numbering system, including, for example, the Kabat numbering and the IMGT unique numbering system, is well known to one skilled in the art (see, e.g., Kabat, supra, Chothia and Lesk, supra, Martin, supra, Lefranc et al., supra) and is also illustrated below. Various systems known in the art or described herein represent different ways of delineating CDRs, and when they are used to define the same antibody, they are often considered equivalent. An Exemplary system, shown herein, combines Kabat and Chothia. The residues from each of these hypervariable regions or CDRs are exemplified in the table below.Exemplary CDRs According to Various Numbering Systems

[0080] Hypervariable regions may comprise “extended hypervariable regions” as follows: 24-36 or 24-34 (LI), 46-56 or 50-56 (L2) and 89-97 or 89-96 (L3) in the VL and 26-35 or 26- 35A (Hl), 50-65 or 49-65 (H2) and 93-102, 94-102, or 95-102 (H3) in the VH. As usedherein, the terms “hypervariable region,” “HVR,” “HV,” “complementarity determining region,” or “CDR” are used interchangeably.

[0081] “Polynucleotide” or “nucleic acid,” as used interchangeably herein, refers to polymers of nucleotides of any length and includes DNA and RNA. The nucleotides can be deoxyribonucleotides, ribonucleotides, modified nucleotides or bases, and / or their analogs, or any substrate that can be incorporated into a polymer by DNA or RNA polymerase or by a synthetic reaction. A polynucleotide may comprise modified nucleotides, such as methylated nucleotides and their analogs. A cell that produces a binding molecule of the present disclosure may include a parent hybridoma cell, as well as bacterial and eukaryotic host cells into which nucleic acids encoding the antibodies have been introduced. Unless specified otherwise, the left-hand end of any single-stranded polynucleotide sequence disclosed herein is the 5’ end; the left-hand direction of double-stranded polynucleotide sequences is referred to as the 5’ direction. The direction of 5’ to 3’ addition of nascent RNA transcripts is referred to as the transcription direction; sequence regions on the DNA strand having the same sequence as the RNA transcript that are 5’ to the 5’ end of the RNA transcript are referred to as “upstream sequences”; sequence regions on the DNA strand having the same sequence as the RNA transcript that are 3 ’ to the 3 ’ end of the RNA transcript are referred to as “downstream sequences.”

[0082] The term “vector” refers to a substance that is used to carry or include a nucleic acid sequence, including for example, in order to introduce a nucleic acid sequence into a host cell. Vectors applicable for use include, for example, expression vectors, plasmids, phage vectors, viral vectors, episomes and artificial chromosomes, which can include selection sequences or markers operable for stable integration into a host cell’s chromosome. Additionally, the vectors can include one or more selectable marker genes and appropriate expression control sequences. Selectable marker genes that can be included, for example, provide resistance to antibiotics or toxins, complement auxotrophic deficiencies, or supply critical nutrients not in the culture media. Expression control sequences can include constitutive and / or inducible promoters, transcription enhancers, transcription terminators, and the like which are well known in the art. When two or more nucleic acid molecules are to be co-expressed (e.g., both an antibody heavy and light chain or an antibody VH and VL) both nucleic acid molecules can be inserted, for example, into a single expression vector or in separate expression vectors. For single vector expression, the encoding nucleic acids can be operationally linked to one common expression control sequence or linked to different expression control sequences, such as one inducible promoter and one constitutive promoter.The introduction of nucleic acid molecules into a host cell can be confirmed using methods well known in the art. Such methods include, for example, nucleic acid analysis such as Northern blots or polymerase chain reaction (PCR) amplification of mRNA, or immunoblotting for expression of gene products, or other suitable analytical methods to test the expression of an introduced nucleic acid sequence or its corresponding gene product. It is understood by those skilled in the art that the nucleic acid molecules are expressed in a sufficient amount to produce a desired product (e.g., an IL13Ra2 binding agent as described herein), and it is further understood that expression levels can be optimized to obtain sufficient expression using methods well known in the art.

[0083] The term “pharmaceutically acceptable” as used herein means being approved by a regulatory agency of the federal or a state government, or listed in the U.S. Pharmacopeia, European Pharmacopeia or other generally recognized Pharmacopeia for use in animals, and more particularly in humans.

[0084] “Excipient” means a pharmaceutically-acceptable material, composition, or vehicle, such as a liquid or solid filler, diluent, solvent, or encapsulating material. Excipients include, for example, encapsulating materials or additives such as absorption accelerators, antioxidants, binders, buffers, carriers, coating agents, coloring agents, diluents, disintegrating agents, emulsifiers, extenders, fillers, flavoring agents, humectants, lubricants, perfumes, preservatives, propellants, releasing agents, sterilizing agents, sweeteners, solubilizers, wetting agents and mixtures thereof. The term “excipient” can also refer to a diluent, adjuvant (e.g., Freunds’ adjuvant (complete or incomplete)) or vehicle. In some embodiments, excipients are pharmaceutically acceptable excipients. Examples of pharmaceutically acceptable excipients include buffers, such as phosphate, citrate, and other organic acids; antioxidants, including ascorbic acid; low molecular weight (e.g., fewer than about 10 amino acid residues) polypeptide; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers, such as polyvinylpyrrolidone; amino acids, such as glycine, glutamine, asparagine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates, including glucose, mannose, or dextrins; chelating agents, such as EDTA; sugar alcohols, such as mannitol or sorbitol; salt-forming counterions, such as sodium; and / or nonionic surfactants, such as TWEEN™, polyethylene glycol (PEG), and PLURONICS™. Other examples of pharmaceutically acceptable excipients are described in Remington and Gennaro, Remington’s Pharmaceutical Sciences (18th ed. 1990). In one embodiment, each component is “pharmaceutically acceptable” in the sense of being compatible with the other ingredients of a pharmaceutical formulation, and suitable for use in contact with the tissue ororgan of humans and animals without excessive toxicity, irritation, allergic response, immunogenicity, or other problems or complications, commensurate with a reasonable benefit / risk ratio. See, e.g., Lippincott Williams & Wilkins: Philadelphia, PA, 2005; Handbook of Pharmaceutical Excipients, 6th ed.; Rowe et al., Eds.; The Pharmaceutical Press and the American Pharmaceutical Association: 2009; Handbook of Pharmaceutical Additives, 3rd ed.; Ash and Ash Eds.; Gower Publishing Company: 2007; Pharmaceutical Preformulation and Formulation, 2nd ed.; Gibson Ed.; CRC Press LLC: Boca Raton, FL, 2009. In some embodiments, pharmaceutically acceptable excipients are nontoxic to the cell or mammal being exposed thereto at the dosages and concentrations employed. In some embodiments, a pharmaceutically acceptable excipient is an aqueous pH buffered solution.In some embodiments, excipients are sterile liquids, such as water and oils, including those of petroleum, animal, vegetable, or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil, and the like. Water is an exemplary excipient when a composition (e.g., a pharmaceutical composition) is administered intravenously. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid excipients, particularly for injectable solutions. An excipient can also include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol, and the like. The composition, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. Compositions can take the form of solutions, suspensions, emulsion, tablets, pills, capsules, powders, sustained-release formulations, and the like. Oral compositions, including formulations, can include standard excipients such as pharmaceutical grades of mannitol, lactose, starch, magnesium stearate, sodium saccharine, cellulose, magnesium carbonate, etc. Compositions, including pharmaceutical compounds, may contain a prophylactically or therapeutically effective amount of an IL13Ra2 binding agent (e.g., an antibody), for example, in isolated or purified form, together with a suitable amount of excipient so as to provide the form for proper administration to the subject (e.g., patient). The formulation should suit the mode of administration.

[0085] An “effective amount” is generally an amount sufficient to reduce the severity and / or frequency of symptoms, eliminate the symptoms and / or underlying cause, prevent or delay the occurrence of symptoms and / or their underlying cause, and / or improve or remediate the damage that results from or is associated with a disease, disorder, or condition. In some embodiments, the effective amount is a therapeutically effective amount or a prophylactically effective amount.

[0086] The term “therapeutically effective amount” as used herein refers to the amount of an agent (e.g., an antibody described herein or any other agent described herein) that is sufficient to reduce and / or ameliorate the severity and / or duration of a given disease, disorder or condition, and / or a symptom related thereto. A therapeutically effective amount of an agent, including a therapeutic agent, can be an amount necessary for (i) reduction, delay or amelioration of the advancement or progression of a given disease, disorder, or condition, (ii) reduction, delay or amelioration of the recurrence, development or onset of a given disease, disorder or conditions, and / or (iii) to improve or enhance the prophylactic or therapeutic effect of another therapy (e.g., a therapy other than the administration of an agent described herein). A “therapeutically effective amount” of a substance / molecule / agent of the present disclosure (e.g., an IL13Ra2 antibody) may vary according to factors such as the disease state, age, sex, and weight of the individual, and the ability of the substance / molecule / agent, to elicit a desired response in the individual. A therapeutically effective amount encompasses an amount in which any toxic or detrimental effects of the substance / molecule / agent are outweighed by the therapeutically beneficial effects. In certain embodiments, the term “therapeutically effective amount” refers to an amount of an agent effective to “treat” a disease, disorder, or condition, in a subject or mammal.

[0087] The term “treating” or any grammatical variation thereof refers to reducing and / or ameliorating the severity and / or duration of a given disease, disorder or condition, and / or a symptom related thereto, such as (i) reduction, delay or amelioration of the advancement or progression of a given disease, disorder, or condition, (ii) reduction, delay or amelioration of the recurrence, development or onset of a given disease, disorder or conditions, and / or (iii) to improve or enhance the prophylactic or therapeutic effect of another therapy (e.g., a therapy other than the administration of an agent described herein).

[0088] A “prophylactically effective amount” is an amount of a pharmaceutical composition that, when administered to a subject, will have the intended prophylactic effect, e.g., preventing or delaying the onset (or reoccurrence) of a disease, disorder or condition, or reducing the likelihood of the onset (or reoccurrence) of a disease, disorder, or condition or associated symptom(s).

[0089] The full therapeutic or prophylactic effect does not necessarily occur by administration of one dose, and may occur only after administration of a series of doses. Thus, a therapeutically or prophylactically effective amount may be administered in one or more administrations.

[0090] The terms “about” and “approximately” mean within 20%, within 15%, within 10%, within 9%, within 8%, within 7%, within 6%, within 5%, within 4%, within 3%, within 2%, within 1%, or less variation of a given value or range.

[0091] As used herein, comparative terms as used herein, such as reduce, decrease, increase, or any grammatical variation thereof, can refer to certain variation from the reference. In some embodiments, such variation can refer to about 10%, or about 20%, or about 30%, or about 40%, or about 50%, or about 60%, or about 70%, or about 80%, or about 90%, or about 1 fold, or about 2 fold, or about 3 fold, or about 4 fold, or about 5 fold, or about 10 fold, or about 20 fold, or about 30 fold, or about 40 fold, or about 100 fold or higher than the reference. In some embodiments, such variation can refer to about 1%, or about 2%, or about 3%, or about 4%, or about 5%, or about 6%, or about 7%, or about 8%, or about 9%, or about 10%, or about 20%, or about 30%, or about 40%, or about 50%, or about 60%, or about 70%, or about 80%, or about 90%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99% of the reference.

[0092] As used in the present disclosure and claims, the singular forms “a”, “an” and “the” include plural forms unless the context clearly dictates otherwise.

[0093] In some embodiments, the terms “first,” “second,” “third,” “fourth” and similar in a component name are used to distinguish and identify more than one component sharing certain identity in their names. For example, “first antibody” and “second antibody” are used to distinguish two antibodies.

[0094] It is understood that wherever embodiments are described herein with the term “comprising” otherwise analogous embodiments described in terms of “consisting of’ and / or “consisting essentially of’ are also provided. It is also understood that wherever embodiments are described herein with the phrase “consisting essentially of’ otherwise analogous embodiments described in terms of “consisting of’ are also provided.

[0095] The term “between” as used in a phrase as such “between A and B” or “between A- B” refers to a range including both A and B.

[0096] The term “and / or” as used in a phrase such as “A and / or B” herein is intended to include both A and B; A or B; A (alone); and B (alone). Likewise, the term “and / or” as used in a phrase such as “A, B, and / or C” is intended to encompass each of the following embodiments: A, B, and C; A, B, or C; A or C; A or B; B or C; A and C; A and B; B and C; A (alone); B (alone); and C (alone).

[0097] The term “optional” or “optionally” means that the subsequently described circumstance may or may not occur, so that the description includes instances wherein the circumstance occurs, and the instances wherein the circumstance does not occur.5.2. IL13Ra2 Binding Agents

[0098] In some embodiments, the present disclosure provides IL13Ra2 binding agents that can be used herein as therapeutic agents for treatment of cancer. Examples of cancers include, but are not limited to: melanoma, lung cancer (including non-small cell lung cancer, NSCLC), colorectal cancer, malignant gliomas, pancreatic cancer, ovarian cancer, breast cancer, liver cancer, head and neck cancer, and renal cancer. Such agents include antibodies (e.g., monospecific or multispecific, including bispecific) that bind to IL13Ra2 (or an IL13Ra2:IL13 complex). Exemplary antibodies include polyclonal, monoclonal, humanized, human, bispecific, and heteroconjugate antibodies, as well as variants thereof having increased or decreased affinity or other properties.

[0099] In some embodiments, described herein are IL13Ra2 binding agents (e.g., antibodies) that bind to IL13Ra2, including an IL13Ra2 polypeptide, an IL13Ra2 polypeptide fragment, an IL13Ra2 peptide, an IL13Ra2:IL13 complex, or an IL13Ra2 epitope. In some embodiments, the IL13Ra2 binding agents are human or humanized antibodies (e.g., comprising human constant regions) that bind IL13Ra2, including an IL13Ra2 polypeptide, an IL13Ra2 polypeptide fragment, an IL13Ra2 peptide or an IL13Ra2 epitope. In some embodiments, an IL13Ra2 binding agent (e.g., an antibody), such as a human IL13Ra2 binding agent, can bind to IL13Ra2 expressed on the surface of a mammalian (e.g., human) cell, including an IL13Ra2 expressing cancer cell. In some embodiments, an IL13Ra2 binding agent (e.g., an antibody), such as a human IL13Ra2 binding agent, can bind to IL13Ra2 expressed on the surface of a mammalian (e.g., human) cell, including an IL13Ra2 overexpressing cancer cell. In some embodiments, an IL13Ra2 binding agent (e.g, an antibody) binds an IL13Ra2 extracellular epitope exposed on a cell such as a cancer cell. In some embodiments, an IL13Ra2 binding agent (e.g, an antibody) binds to a complex comprising IL13Ra2 and IL13. In some embodiments, an IL13Ra2 binding agent (e.g., an antibody) binds to a complex comprising the extracellular domain (ECD) of IL13Ra2 and IL13. In yet further embodiments, an IL13Ra2 binding agent (e.g., an antibody) binds to an epitope of a complex comprising the ECD of IL13Ra2 and IL 13. In some embodiments, described herein is an IL13Ra2 binding agent (e.g., an antibody) that binds to IL13Ra2, such as human IL13Ra2 or a portion thereof. In some embodiments, IL13Ra2 is a human IL13Ra2. In some embodiments, an IL13Ra2 binding agent is a humanIL13Ra2 binding agent (e.g., an antibody that binds to human IL13Ra2). In some embodiments, IL13Ra2 binding agents (e.g., antibodies) bind to both human and cyno IL13Ra2. In other embodiments, IL13Ra2 binding agents (e.g., antibodies) bind to human IL13Ra2 but not to cyno IL13Ra2.

[0100] In some embodiments, the IL13Ra2 binding agent (e.g., an antibody) provided herein binds to IL13Ra2 (e.g., human IL13Ra2 and / or cyno IL13Ra2) with a dissociation constant (KD) of < 1 pM, < 100 nM, < 10 nM, < 1 nM, < 0.1 nM, < 0.01 nM, or < 0.001 nM (e.g. 10'8M or less, e.g. from 10'8M to 10'13M, e.g., from 10'9M to 10'13M). A variety of methods of measuring binding affinity are known in the art, any of which can be used for purposes of the present disclosure, including by RIA, for example, performed with the Fab version of an antibody of interest and its antigen (Chen et al., 1999, J. Mol Biol 293:865-81); by biolayer interferometry (BLI) or surface plasmon resonance (SPR) assays by OCTET®, using, for example, an OCTET®Red96 system, or by BIACORE®, using, for example, a BIACORE®TM-2000 or a BIACORE®TM-3000. An “on-rate” or “rate of association” or “association rate” or “kon” may also be determined with the same biolayer interferometry (BLI) or surface plasmon resonance (SPR) techniques described above using, for example, the OCTET®Red96, the BIACORE®TM-2000, the BIACORE®TM-3000 system, the BIACORE®TM-8K, or the BIACORE®TM-8K+ system.

[0101] In some embodiments, the IL13Ra2 binding agent (e.g., an antibody) provided herein does not bind to IL13Ral (e.g., human IL13Ral and / or cyno IL13Ral). In some embodiments, the IL13Ra2 binding agent (e.g., an antibody) provided herein does not bind to human IL13Ral. In some embodiments, the IL13Ra2 binding agent (e.g., an antibody) provided herein does not bind to human IL13Ral or cyno IL13Ral. In other embodiments, the IL13Ra2 binding agent (e.g., an antibody) provided herein binds to IL13Ra2 (e.g., human IL13Ra2) with higher affinity than to IL13Ral (e.g., human IL13Ral). In some embodiments, the binding affinity of the IL13Ra2 binding agent (e.g., an antibody) provided herein to IL13Ra2 (e.g., human IL13Ra2) is at least 2 fold of that to IL13Ral (e.g., human IL13Ral). In some embodiments, the binding affinity of the IL13Ra2 binding agent (e.g., an antibody) provided herein to IL13Ra2 (e.g., human IL13Ra2) is at least 5 fold of that to IL13Ral (e.g., human IL13Ral). In some embodiments, the binding affinity of the IL13Ra2 binding agent (e.g., an antibody) provided herein to IL13Ra2 (e.g., human IL13Ra2) is at least 10 fold of that to IL13Ral (e.g., human IL13Ral). In some embodiments, the binding affinity of the IL13Ra2 binding agent (e.g., an antibody) provided herein to IL13Ra2 (e.g., human IL13Ra2) is at least 100 fold of that to IL13Ral (e.g., human IL13Ral). In someembodiments, the binding affinity of the IL13Ra2 binding agent (e.g., an antibody) provided herein to IL13Ra2 (e.g., human IL13Ra2) is at least 1000 fold of that to IL13Ral (e.g., human IL13Ral).

[0102] Additionally or alternatively, the IL13Ra2 binding agent (e.g., an antibody) provided herein does not block the binding between IL 13 and IL13Ra2 (e.g., human IL13Ra2 and / or cyno IL13Ra2).

[0103] In some embodiments, the IL13Ra2 binding agents (e.g., antibodies) described herein comprise a VH region, VL region, VH CDR1, VH CDR2, VH CDR3, VL CDR1, VL CDR2, and / or VL CDR3 of any one of the antibodies described herein, such as an amino acid sequence of a VH region, VL region, VH CDR1, VH CDR2, VH CDR3, VL CDR1, VL CDR2, and / or VL CDR3 depicted in Tables 1-3. Accordingly, in some embodiments, an IL13Ra2 binding agent (e.g., an antibody) described herein comprises any one, any two, and / or all three heavy chain CDRs and / or any one, any two, and / or all three light chain CDRs from: (a) the antibody designated A22; (b) the antibody designated A33; and (c) the antibody designated A52, as shown in Tables 1-3. In some embodiments, an IL13Ra2 binding agent (e.g., an antibody) described herein comprises any one, any two, and / or all three heavy chain CDRs and any one, any two, and / or all three light chain CDRs from: (a) the antibody designated A22; (b) the antibody designated A33; and (c) the antibody designated A52, as shown in Tables 1-3.

[0104] In some embodiments, an IL13Ra2 binding agent (e.g., an antibody) comprises a VH region, which comprises a VH CDR1, a VH CDR2, and / or a VH CDR3, and / or a VL region, which comprises a VL CDR1, a VL CDR2, and / or a VL CDR3, of any one of the binding agents described herein (see, e.g., any one of Tables 1-3). Accordingly, in some embodiments, an IL13Ra2 binding agent (e.g., an antibody) described herein comprises any one, any two, and / or all three heavy chain CDRs and / or any one, any two, and / or all three light chain CDRs from Table 1. In some embodiments, an IL13Ra2 binding agent (e.g., an antibody) described herein comprises any one, any two, and / or all three heavy chain CDRs and / or any one, any two, and / or all three light chain CDRs from Table 2. In some embodiments, an IL13Ra2 binding agent (e.g., an antibody) described herein comprises any one, any two, and / or all three heavy chain CDRs and / or any one, any two, and / or all three light chain CDRs from Table 3.

[0105] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises (i) a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:25, SEQ ID NO:48, or SEQ ID NO:73and / or (ii) a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:26, SEQ ID NO:49, or SEQ ID NO:74.

[0106] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH CDR1, a VH CDR2, and / or a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:25 and / or a VL CDR1, a VL CDR2, and / or a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:26. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:25 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:26. CDR sequences can be determined according to well-known numbering systems or a combination thereof. In some embodiments, the CDRs are according to IMGT numbering. In some embodiments, the CDRs are according to Kabat numbering. In some embodiments, the CDRs are according to AbM numbering. In other embodiments, the CDRs are according to Chothia numbering. In other embodiments, the CDRs are according to Contact numbering. In some embodiments, the CDR sequences are determined according to a combination of any two or more of the above-mentioned numbering systems, for example, a combination of Kabat and Chothia. Various exemplary CDR numbering systems are described and illustrated above in Section 5.1.

[0107] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises (a) a VH region comprising a VH CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 1, 2, 3, 4, and 5; a VH CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 6, 7, 8, 9, and 10; and a VH CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 11, 12, 13, and 14; and / or (b) a VL region comprising a VL CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 15, 16, 17, and 18; a VL CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 19, 20, and 21; and a VL CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 22, 23, and 24.

[0108] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 1, a VH CDR2 comprising the amino acid sequence of SEQ ID NO: 6, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 15, a VLCDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22.

[0109] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:2, a VH CDR2 comprising the amino acid sequence of SEQ ID NO: 7, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 12; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 16, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22.

[0110] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:3, a VH CDR2 comprising the amino acid sequence of SEQ ID NO: 6, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 15, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22.

[0111] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NON, a VH CDR2 comprising the amino acid sequence of SEQ ID NO: 8, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 13; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 17, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:23.

[0112] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:5, a VH CDR2 comprising the amino acid sequence of SEQ ID NOV, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 14; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 18, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:21, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:24.

[0113] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 1, a VH CDR2 comprising the amino acid sequence of SEQ ID NO: 10, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and a VLregion comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 15, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22.

[0114] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH CDR1, a VH CDR2, and / or a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:48 and / or a VL CDR1, a VL CDR2, and / or a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:49. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:48 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:49. CDR sequences can be determined according to well-known numbering systems or a combination thereof. In some embodiments, the CDRs are according to IMGT numbering. In some embodiments, the CDRs are according to Kabat numbering. In some embodiments, the CDRs are according to AbM numbering. In other embodiments, the CDRs are according to Chothia numbering. In other embodiments, the CDRs are according to Contact numbering. In some embodiments, the CDR sequences are determined according to a combination of any two or more of the above-mentioned numbering systems, for example, a combination of Kabat and Chothia.

[0115] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises (a) a VH region comprising a VH CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 27, 28, 29, 30, and 31; a VH CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 32, 33, 34, 35, and 36; and a VH CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 37, 38, 39, and 40; and / or (b) a VL region comprising a VL CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 41, 42, 43, and 44; a VL CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 19, 20, and 21; and a VL CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 45, 46, and 47.

[0116] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:27, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:32, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:37; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:41, a VLCDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45.

[0117] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:28, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:33, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:38; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:42, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45.

[0118] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:29, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:32, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:37; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:41, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45.

[0119] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 30, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:34, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:39; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:43, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:46.

[0120] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 31, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:35, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:40; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:44, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:21, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:47.

[0121] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:27, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:36, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:37; and a VLregion comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:41, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45.

[0122] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH CDR1, a VH CDR2, and / or a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:73 and / or a VL CDR1, a VL CDR2, and / or a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:74. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:73 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:74. CDR sequences can be determined according to well-known numbering systems or a combination thereof. In some embodiments, the CDRs are according to IMGT numbering. In some embodiments, the CDRs are according to Kabat numbering. In some embodiments, the CDRs are according to AbM numbering. In other embodiments, the CDRs are according to Chothia numbering. In other embodiments, the CDRs are according to Contact numbering. In some embodiments, the CDR sequences are determined according to a combination of any two or more of the above-mentioned numbering systems, for example, a combination of Kabat and Chothia.

[0123] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises (a) a VH region comprising a VH CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 50, 51, 52, 53, and 54; a VH CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 55, 56, 57, 58, and 59; and a VH CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 60, 61, 62, and 63; and / or (b) a VL region comprising a VL CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 64, 65, 66, and 67; a VL CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 68, 20, and 69; and a VL CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 70, 71, and 72.

[0124] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:50, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:55, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:60; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:64, a VLCDR2 comprising the amino acid sequence of SEQ ID NO:68, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70.

[0125] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:51, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:56, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:61; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:65, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70.

[0126] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 52, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:55, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:60; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:64, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:68, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70.

[0127] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:53, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:57, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:62; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:66, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:71.

[0128] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 54, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:58, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:63; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:67, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:69, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:72.

[0129] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:50, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:59, and a VH CDR3 comprising the amino acid sequence of SEQ ID NO:60; and a VLregion comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:64, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:68, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70.

[0130] In some embodiments, the antibody further comprises one or more framework regions of SEQ ID NOs:25, 26, 48, 49, 73, and / or 74. In some embodiments, the antibody or fragment thereof further comprises a framework 1 (FR1), a framework 2 (FR2), a framework 3 (FR3) and / or a framework 4 (FR4) sequence as set forth in any one of SEQ ID NOs: 25, 26, 48, 49, 73, and 74. In some embodiments, the antibody provided herein is a humanized antibody. Framework regions described herein are determined based upon the boundaries of the CDR numbering system. In other words, if the CDRs are determined by, e.g., Kabat, IMGT, or Chothia, then the framework regions are the amino acid residues surrounding the CDRs in the variable region in the format, from the N-terminus to C-terminus: FR1-CDR1- FR2-CDR2-FR3-CDR3-FR4. For example, FR1 is defined as the amino acid residues N- terminal to the CDR1 amino acid residues as defined by, e.g., the Kabat numbering system, the IMGT numbering system, or the Chothia numbering system, FR2 is defined as the amino acid residues between CDR1 and CDR2 amino acid residues as defined by, e.g., the Kabat numbering system, the IMGT numbering system, or the Chothia numbering system, FR3 is defined as the amino acid residues between CDR2 and CDR3 amino acid residues as defined by, e.g., the Kabat numbering system, the IMGT numbering system, or the Chothia numbering system, and FR4 is defined as the amino acid residues C-terminal to the CDR3 amino acid residues as defined by, e.g., the Kabat numbering system, the IMGT numbering system, or the Chothia numbering system.

[0131] In some embodiments, IL13Ra2 binding agents (e.g., antibodies such as monospecific or bispecific antibodies), including human IL13Ra2 binding agents, described herein comprise a VH region or VH domain. Additionally or alternatively, in some embodiments, IL13Ra2 binding agents (e.g., antibodies such as monospecific or bispecific antibodies), including human IL13Ra2 binding agents, described herein comprise a VL region or VL domain. In some embodiments, IL13Ra2 binding agents (e.g., antibodies such as monospecific or bispecific antibodies), including human IL13Ra2 binding agents, described herein have a combination of (i) a VH domain or VH region; and (ii) a VL domain or VL region.

[0132] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH comprising the amino acid sequence of SEQ ID NO:25. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VLcomprising the amino acid sequence of SEQ ID NO:26. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH comprising the amino acid sequence of SEQ ID NO:25 and a VL comprising the amino acid sequence of SEQ ID NO:26.

[0133] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH comprising the amino acid sequence of SEQ ID NO:48. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VL comprising the amino acid sequence of SEQ ID NO:49. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH comprising the amino acid sequence of SEQ ID NO:48 and a VL comprising the amino acid sequence of SEQ ID NO:49.

[0134] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH comprising the amino acid sequence of SEQ ID NO:73. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VL comprising the amino acid sequence of SEQ ID NO:74. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) comprises a VH comprising the amino acid sequence of SEQ ID NO:73 and a VL comprising the amino acid sequence of SEQ ID NO:74.

[0135] In certain embodiments, the IL13Ra2 binding agent (e.g., an antibody of a fragment thereof) provided herein comprises amino acid sequences with certain percent identity (such as at least about 80%, or at least about 81%, or at least about 82%, or at least about 83%, or at least about 84%, or at least about 85%, or at least about 86%, or at least about 87%, or at least about 88%, or at least about 89%, or as at least about 90%, or at least about 91%, or at least about 92%, or at least about 93%, or at least about 94%, or at least about 95%, or at least about 96%, or at least about 97%, or at least about 98%, or at least about 99%, or higher) relative to any antibody or fragment thereof provided herein, for example, a CDR, VH or VL in Tables 1-3, or any full-length antibody chain as disclosed herein. In some embodiments, the IL13Ra2 binding agent (e.g, an antibody of a fragment thereof) provided herein comprises CDRs of any antibody or fragment thereof provided herein, for example in Tables 1-3. In further embodiments, the IL13Ra2 binding agent provided herein comprises amino acid sequences with certain percent identity (such as at least about 80%, or at least about 81%, or at least about 82%, or at least about 83%, or at least about 84%, or at least about 85%, or at least about 86%, or at least about 87%, or at least about 88%, or at least about 89%, or as at least about 90%, or at least about 91%, or at least about 92%, or at least about93%, or at least about 94%, or at least about 95%, or at least about 96%, or at least about 97%, or at least about 98%, or at least about 99%, or higher) relative to any antibody or fragment thereof provided herein, for example, a VH or VL in Tables 1-3, or any full-length antibody chain as disclosed herein.

[0136] The determination of percent identity between two sequences (e.g., amino acid sequences or nucleic acid sequences) can be accomplished using a mathematical algorithm. A non-limiting example of a mathematical algorithm utilized for the comparison of two sequences is the algorithm of Karlin and Altschul, Proc. Natl. Acad. Sci. U.S.A. 87:2264 2268 (1990), modified as in Karlin and Altschul, Proc. Natl. Acad. Sci. U.S.A. 90:5873 5877 (1993). Such an algorithm is incorporated into the NBLAST and XBLAST programs of Altschul et al., J. Mol. Biol. 215:403 (1990). BLAST nucleotide searches can be performed with the NBLAST nucleotide program parameters set, e.g., for score=100, word length=12 to obtain nucleotide sequences homologous to a nucleic acid molecule described herein. BLAST protein searches can be performed with the XBLAST program parameters set, e.g., to score 50, word length=3 to obtain amino acid sequences homologous to a protein molecule described herein. To obtain gapped alignments for comparison purposes, Gapped BLAST can be utilized as described in Altschul etal., Nucleic Acids Res. 25:3389 3402 (1997). In some embodiments, the percent identity between two sequences is calculated by dividing the number of residue(s) varied (excluding or including conservative amino acid substitution(s) or degenerate nucleotide substitution(s)) between the two sequences in the alignment with the residue number of any one of the following: (i) full length of the shorter sequence, (ii) full length of the longer sequence, (iii) mean length of the two sequences, (iv) total length of the non-gap portion of the alignment, (v) length of the alignment excluding overhangs, or (vi) length of the alignment including overhangs. Overhangs as used herein with respect to a sequence alignment refer to either or both ends of the alignment where residues of one sequence are considered as aligning to no residues (e.g., gap) in the other sequence.Alternatively, PSI BLAST can be used to perform an iterated search which detects distant relationships between molecules (Id.). When utilizing BLAST, Gapped BLAST, and PSI Blast programs, the default parameters of the respective programs (e.g., of XBLAST and NBLAST) can be used (see, e.g., National Center for Biotechnology Information (NCBI) on the worldwide web, ncbi.nlm.nih.gov). Another non-limiting example of a mathematical algorithm utilized for the comparison of sequences is the algorithm of Myers and Miller, CAB IOS 4: 11-17 (1998). Such an algorithm is incorporated in the ALIGN program (version 2.0) which is part of the GCG sequence alignment software package. When utilizing theALIGN program for comparing amino acid sequences, a PAM120 weight residue table, a gap length penalty of 12, and a gap penalty of 4 can be used. The percent identity between two sequences can be determined using techniques similar to those described above, with or without allowing gaps. In calculating percent identity, typically only exact matches are counted.

[0137] In some embodiments, the binding agent (e.g., an antibody) provided herein contains substitutions (e.g., conservative substitutions), insertions, or deletions relative to the reference sequence, but the binding agent comprising that sequence retains the ability to bind to IL13Ra2. In some embodiments, a total of 1 to 10 amino acids have been substituted, inserted and / or deleted in a reference amino acid sequence. In some embodiments, substitutions, insertions, or deletions occur in regions outside the CDRs (e.g., in the FRs and / or constant regions).

[0138] In some embodiments, the position of one or more CDRs along the VH (e.g., CDR1, CDR2, or CDR3) and / or VL (e.g, CDR1, CDR2, or CDR3) region of an IL13Ra2 binding agent (e.g, an antibody), including a human IL13Ra2 binding agent, described herein may vary by one, two, three, four, five, or six amino acid positions so long as binding to IL13Ra2 (e.g., human IL13Ra2) is maintained (e.g., substantially maintained, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%). For example, in some embodiments, the position defining a CDR of any of Table 1, 2, or 3 may vary by shifting the N-terminal and / or C-terminal boundary of the CDR by one, two, three, four, five, or six amino acids, relative to the current CDR position, so long as binding to IL13Ra2 (e.g., human IL13Ra2) is maintained (e.g., substantially maintained, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%). Additionally or alternatively, in some embodiments, the length of one or more CDRs along the VH (e.g., CDR1, CDR2, or CDR3) and / or VL (e.g., CDR1, CDR2, or CDR3) region of an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, described herein may vary (e.g., be shorter or longer) by one, two, three, four, five, or more amino acids, so long as binding to IL13Ra2 (e.g., human IL13Ra2) is maintained (e.g., substantially maintained, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%). For example, in some embodiments, a VH and / or VL CDR1, CDR2, and / or CDR3 described herein may be one, two, three, four, five or more amino acids shorter than one or more of the CDRs described by SEQ ID NOS: 1-24, 27-47, or 50-72, so long as binding to IL13Ra2 (e.g., human IL13Ra2) is maintained (e.g., substantially maintained, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%).In other embodiments, a VH and / or VL CDR1, CDR2, and / or CDR3 described herein may be one, two, three, four, five or more amino acids longer than one or more of the CDRs described by SEQ ID NOS: 1-24, 27-47, or 50-72, so long as binding to IL13Ra2 (e.g., human IL13Ra2) is maintained (e.g., substantially maintained, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%). In some embodiments, the amino terminus of a VH and / or VL CDR1, CDR2, and / or CDR3 described herein may be extended or shortened by one, two, three, four, five or more amino acids compared to one or more of the CDRs described by SEQ ID NOS: 1-24, 27-47, or 50-72, so long as binding to IL13Ra2 (e.g., human IL13Ra2) is maintained (e.g., substantially maintained, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%).Additionally or alternatively, in some embodiments, the carboxy terminus of a VH and / or VL CDR1, CDR2, and / or CDR3 described herein may be extended or shortened by one, two, three, four, five or more amino acids compared to one or more of the CDRs described by SEQ ID NOS: 1-24, 27-47, or 50-72, so long as binding to IL13Ra2 (e.g., human IL13Ra2) is maintained (e.g., substantially maintained, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%). Any method known in the art can be used to ascertain whether binding to IL13Ra2 (e.g., human IL13Ra2) is maintained, for example, the binding assays and conditions described in the “Examples” section described herein.

[0139] In other embodiments, the IL13Ra2 binding agents (e.g., antibodies), including human IL13Ra2 binding agents, presented herein that bind to IL13Ra2, further comprise conservative sequence modifications. With respect to polypeptides that are IL13Ra2 binding agents (e.g., antibodies), such as human IL13Ra2 binding agents, conservative sequence modifications include conservative amino acid substitutions that include ones in which the amino acid residue is replaced with an amino acid residue having a similar side chain.Families of amino acid residues having similar side chains have been defined in the art. Thus, in some embodiments, a predicted nonessential amino acid residue in an IL13Ra2 is replaced with another amino acid residue from the same side chain family. Methods of identifying amino acid conservative substitutions which do not eliminate antigen binding and nucleotides encoding thereof are well-known in the art (see, e.g., Brummell et al., Biochem. 32: 1 ISO- 1187 (1993); Kobayashi et al. Protein Eng. 12(10):879-884 (1999); and Burks et al. Proc. Natl. Acad. Sci. USA 94:412-417 (1997)). In some embodiments, the conservative sequence modifications described herein modify the amino acid sequences of the IL13Ra2 binding agents (e.g., antibodies), including human IL13Ra2 binding agents, by 50%, or 55%, or 60%, or 65%, or 70%, or 75%, or 80%, or 85%, or 90%, or 95%, or 98%, or 99%. In someembodiments, the amino acid sequence modifications refer to at most 1, 2, 3, 4, 5, or 6 amino acid substitutions to the CDRs, such as those described in any one of Tables 1-3. Thus, for example, each such CDR may contain up to 5 conservative amino acid substitutions, for example up to (not more than) 4 conservative amino acid substitutions, for example up to (not more than) 3 conservative amino acid substitutions, for example up to (not more than) 2 conservative amino acid substitutions, or no more than 1 conservative amino acid substitution. In some embodiments, an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, contains one or more, including six, CDRs having at least 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to the CDRs of A22, A33, or A52 (see, e.g., Tables 1, 2, or 3).

[0140] In some embodiments, an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, contains a VH and a VL comprising CDRs identical to those of A22, A33, or A52 (see, e.g., Tables 1, 2, or 3). In some embodiments, the amino acid sequence modifications do not include any modification within an SDR. In some embodiments, the amino acid sequence modifications do not include any modification within a CDR (such as CDR1, CDR2, CDR3, or any combination thereof). Additionally or alternatively, the amino acid sequence modifications are in the framework, constant region, and / or fragment crystallizable region (Fc).

[0141] In some embodiments, the antibody or fragment provided herein comprises a VH domain having at least 75%, at least 80%, at least 85%, 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%, or at least 99% sequence identity to the amino acid sequence of SEQ ID NO:25, and / or a VL domain having at least 75%, at least 80%, at least 85%, 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%, or at least 99% sequence identity to the amino acid sequence of SEQ ID NO:26, and the binding of the antibody or fragment thereof to IL13Ra2 (e.g., human IL13Ra2) is maintained (e.g., substantially maintained, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%).

[0142] In some embodiments, the antibody or fragment provided herein comprises a VH domain having at least 75%, at least 80%, at least 85%, 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%, or at least 99% sequence identity to the amino acid sequence of SEQ ID NO:48, and / or a VL domain having at least 75%, at least 80%, at least 85%, 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%, or atleast 99% sequence identity to the amino acid sequence of SEQ ID NO:49, and the binding of the antibody or fragment thereof to IL13Ra2 (e.g., human IL13Ra2) is maintained (e.g., substantially maintained, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%).

[0143] In some embodiments, the antibody or fragment provided herein comprises a VH domain having at least 75%, at least 80%, at least 85%, 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%, or at least 99% sequence identity to the amino acid sequence of SEQ ID NO:73, and / or a VL domain having at least 75%, at least 80%, at least 85%, 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%, or at least 99% sequence identity to the amino acid sequence of SEQ ID NO:74, and the binding of the antibody or fragment thereof to IL13Ra2 (e.g., human IL13Ra2) is maintained (e.g., substantially maintained, for example, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%).

[0144] In some embodiments, functional epitopes can be mapped, e.g., by combinatorial alanine scanning, to identify amino acids in the IL13Ra2 protein that are necessary for interaction with IL13Ra2 binding agents (such as antibodies) provided herein. In some embodiments, conformational and crystal structure of IL13Ra2 binding agents (such as antibodies) bound to IL13Ra2 may be employed to identify the epitopes. In some embodiments, the present disclosure provides an antibody that specifically binds to the same epitope as any of the IL13Ra2 binding agents (such as antibodies or fragments thereof) provided herein.

[0145] For example, in some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) binds to the same epitope as an anti-IL13Ra2 antibody comprising a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:25 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:26. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) binds to the same epitope as an anti-IL13Ra2 antibody comprising a VH comprising the amino acid sequence of SEQ ID NO:25, and a VL comprising the amino acid sequence of SEQ ID NO:26.

[0146] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) binds to the same epitope as an anti-IL13Ra2 antibody comprising a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:48 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising theamino acid sequence of SEQ ID NO:49. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) binds to the same epitope as an anti-IL13Ra2 antibody comprising a VH comprising the amino acid sequence of SEQ ID NO:48, and a VL comprising the amino acid sequence of SEQ ID NO:49.

[0147] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) binds to the same epitope as an anti-IL13Ra2 antibody comprising a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:73 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:74. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) binds to the same epitope as an anti-IL13Ra2 antibody comprising a VH comprising the amino acid sequence of SEQ ID NO:73, and a VL comprising the amino acid sequence of SEQ ID NO:74.

[0148] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) specifically binds to IL13Ra2 competitively with any one of the anti-IL13Ra2 antibodies or fragments thereof described herein.

[0149] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) specifically binds to IL13Ra2 competitively with an anti-IL13Ra2 antibody comprising a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:25 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:26. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) specifically binds to IL13Ra2 competitively with an anti-IL13Ra2 antibody comprising a VH comprising the amino acid sequence of SEQ ID NO:25, and a VL comprising the amino acid sequence of SEQ ID NO:26.

[0150] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) specifically binds to IL13Ra2 competitively with an anti-IL13Ra2 antibody comprising a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:48 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:49. In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) specifically binds to IL13Ra2 competitively with an anti-IL13Ra2 antibody comprising a VH comprising the amino acid sequence of SEQ ID NO:48, and a VL comprising the amino acid sequence of SEQ ID NO:49.

[0151] In some embodiments, the IL13Ra2 binding agent provided herein (e.g., an antibody) specifically binds to IL13Ra2 competitively with an anti-IL13Ra2 antibody comprising a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:73 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:74. In some embodiments, the IL13Ra2 binding agent provided herein e.g., an antibody) specifically binds to IL13Ra2 competitively with an anti-IL13Ra2 antibody comprising a VH comprising the amino acid sequence of SEQ ID NO:73, and a VL comprising the amino acid sequence of SEQ ID NO:74.

[0152] In some embodiments, the IL13Ra2 binding agent comprises six CDRs of the antibody designated A22. In yet further embodiments, the IL13Ra2 binding agent comprises six CDRs as listed in one column of Table 1. In some embodiments, the IL13Ra2 binding agent comprises three CDRs of the heavy chain variable region as set forth in SEQ ID NO: 25 and three CDRs of the light chain variable regions as set forth in SEQ ID NO: 26. In some embodiments, the IL13Ra2 binding agent comprises the heavy chain variable region as set forth in SEQ ID NO: 25 and the light chain variable regions as set forth in SEQ ID NO: 26.

[0153] In some embodiments, the IL13Ra2 binding agent comprises six CDRs of the antibody designated A33. In yet further embodiments, the IL13Ra2 binding agent comprises six CDRs as listed in one column of Table 2. In some embodiments, the IL13Ra2 binding agent comprises three CDRs of the heavy chain variable region as set forth in SEQ ID NO: 48 and three CDRs of the light chain variable regions as set forth in SEQ ID NO: 49. In some embodiments, the IL13Ra2 binding agent comprises the heavy chain variable region as set forth in SEQ ID NO: 48 and the light chain variable regions as set forth in SEQ ID NO: 49.

[0154] In some embodiments, the IL13Ra2 binding agent comprises six CDRs of the antibody designated A52. In yet further embodiments, the IL13Ra2 binding agent comprises six CDRs as listed in one column of Table 3. In some embodiments, the IL13Ra2 binding agent comprises three CDRs of the heavy chain variable region as set forth in SEQ ID NO: 73 and three CDRs of the light chain variable regions as set forth in SEQ ID NO:74. In some embodiments, the IL13Ra2 binding agent comprises the heavy chain variable region as set forth in SEQ ID NO: 73 and the light chain variable regions as set forth in SEQ ID NO: 74.

[0155] In some embodiments, the binding agents are superior developability based on a known assay in the art, for example, various chromatographic methods, including size exclusion chromatography (SEC), hydrophobic interaction chromatography (HIC), and standup monolayer adsorption chromatography (SMAC). In some embodiments, the bindingagents are superior developability based on measurement of monomer percentage, solubility, and / or antibody aggregation or precipitation.

[0156] In some embodiments, IL13Ra2 binding agents (e.g., antibodies such as monospecific or bispecific antibodies), including human IL13Ra2 binding agents, described herein comprise a heavy chain having a combination of (i) a VH described herein, such as in any one of Tables 1-3; and (ii) one or more heavy chain constant domains (e.g., CHI, Hinge, CH2, and CH3). An exemplary IgG heavy chain comprises any VH sequence as described herein and the following CHI, Hinge, CH2, and CH3 amino acid sequence:ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVL QSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEPKSCDKTHTCPPCPAP ELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAK TKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPR EPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSD GSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEQ ID NO:77)

[0157] In further embodiments, the carboxyl terminus (C terminus) of the VH is conjugated directly or indirectly to the amino terminus (N terminus) of the one or more heavy chain constant domains.

[0158] In some embodiments, IL13Ra2 binding agents (e.g., antibodies such as monospecific or bispecific antibodies), including human IL13Ra2 binding agents, described herein comprise a light chain having a combination of (i) a VL domain described herein, such as in any one of Tables 1-3; and (ii) a light chain constant domain (CL). An exemplary light chain (e.g., for pairing with an IgG heavy chain) comprises any VL sequence described herein and the following CL amino acid sequence:RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVT EQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO:78)

[0159] In further embodiments, the C terminus of the VL is conjugated directly or indirectly to the N terminus of the CL.

[0160] In some embodiments, IL13Ra2 binding agents (e.g., antibodies such as monospecific or bispecific antibodies), including human IL13Ra2 binding agents, described herein comprise (a) a heavy chain having a combination of (i) a VH described herein, such as in any one of Tables 1-3, and (ii) one or more heavy chain constant domains (e.g., CHI, Hinge, CH2, and CH3); and (b) a light chain having a combination of (i) a VL described herein, such as in any one of Tables 1-3, and (ii) a light chain constant domain in an IgGformat (CL or CL1). An exemplary IL13Ra2 binding agent e.g., an antibody) comprises an IgG heavy chain comprising any VH sequence as described herein and the amino acid sequence of SEQ ID NO:77, and a light chain comprising any VL sequence as described herein and the amino acid sequence of SEQ ID NO:78.

[0161] In some embodiments, IL13Ra2 binding agents (e.g., antibodies such as monospecific or bispecific antibodies), including human IL13Ra2 binding agents, described herein comprise: (a) a heavy chain having the amino acid sequence of SEQ ID NO:75, and (b) a light chain having the amino acid sequence of SEQ ID NO:76. In some embodiments, IL13Ra2 binding agents (e.g., antibodies such as monospecific or bispecific antibodies), including human IL13Ra2 binding agents, described herein comprise: (a) a heavy chain having the amino acid sequence of SEQ ID NO:79, and (b) a light chain having the amino acid sequence of SEQ ID NO:80. In some embodiments, IL13Ra2 binding agents (e.g., antibodies such as monospecific or bispecific antibodies), including human IL13Ra2 binding agents, described herein comprise: (a) a heavy chain having the amino acid sequence of SEQ ID NO:81, and (b) a light chain having the amino acid sequence of SEQ ID NO:82.

[0162] In some embodiments, provided herein is an IL13Ra2 binding protein comprising any one of the anti-IL13Ra2 antibodies described herein. In some embodiments, the IL13Ra2 binding protein is an antibody comprising two heavy chains and two light chains. In some embodiments, the IL13Ra2 binding protein is an antibody comprising two heavy chains comprising a same VH region and two light chains comprising a same VL region.

[0163] In some embodiments, the IL13Ra2 binding protein is a monoclonal antibody, including a mouse, chimeric, humanized or human antibody. In some embodiments, the anti- IL13Ra2 antibody is an antibody fragment, e.g., an scFv. In some embodiments, the IL13Ra2 binding protein is a fusion protein comprising the anti-IL13Ra2 antibody provided herein. In other embodiments, the IL13Ra2 binding protein is a multispecific antibody comprising the anti-IL13Ra2 antibody or fragment thereof provided herein.Other exemplary IL13Ra2 binding molecules are described in more detail in the following sections. In some embodiments, the anti-IL13Ra2 antibody or antigen-binding protein according to any of the above embodiments may incorporate any of the features, singly or in combination, as described in Sections 5.2.1 to 5.2.4 below.Table 1: Antibody Clone A22Table 2: Antibody Clone A33Table 3: Antibody Clone A525.2.1. Antibody Fragments

[0164] Even though the term “antibody” is sometimes used in a phrase of “antibody or fragment thereof’ herein, it should be understood the term “antibody” as used herein also includes various antibody fragments, such as an antigen-binding fragment or epitope-binding fragment. Thus, when the term “antibody” is used alone without being followed by “fragment thereof’ or similar terms, it should be understood the term “antibody” includes an antibody fragment, such as an antigen-binding fragment or epitope-binding fragment. Antibodies provided herein include, but are not limited to, immunoglobulin molecules and immunologically active portions of immunoglobulin molecules.

[0165] Variants and derivatives of antibodies include antibody functional fragments that retain the ability to bind to an antigen. Antibody fragments include but are not limited to those described in Section 5.1 above. Exemplary functional fragments include Fab fragments (e.g., an antibody fragment that contains the antigen-binding domain and comprises a light chain and part of a heavy chain bridged by a disulfide bond); Fab’ (e.g., an antibody fragment containing a single antigen-binding domain comprising an Fab and an additional portion of the heavy chain through the hinge region); F(ab’)2 (e.g., two Fab’ molecules joined by interchain disulfide bonds in the hinge regions of the heavy chains; the Fab’ molecules may be directed toward the same or different epitopes); a bispecific Fab (e.g., a Fab molecule having two antigen-binding domains, each of which may be directed to a different epitope); a single chain comprising a variable region, also known as, scFv (e.g., the variable, antigenbinding determinative region of a single light and heavy chain of an antibody linked together by a chain of, e.g., 10-25 amino acids); a disulfide-linked Fv, or dsFv (e.g., the variable, antigen-binding determinative region of a single light and heavy chain of an antibody linked together by a disulfide bond); a bispecific scFv (e.g., an scFv or a dsFv molecule having two antigen-binding domains, each of which may be directed to a different epitope); a diabody (e.g., a dimerized scFv formed when the VH domain of a first scFv assembles with the VL domain of a second scFv and the VL domain of the first scFv assembles with the VH domain of the second scFv; the two antigen-binding regions of the diabody may be directed towards the same or different epitopes); a triabody (e.g., a trimerized scFv, formed in a manner similar to a diabody, but in which three antigen-binding domains are created in a single complex; the three antigen-binding domains may be directed towards the same or different epitopes); and a tetrabody (e.g., a tetramerized scFv, formed in a manner similar to a diabody, but in which four antigen-binding domains are created in a single complex; the four antigenbinding domains may be directed towards the same or different epitopes).

[0166] Various techniques have been developed for the production of antibody fragments. Traditionally, these fragments were derived via proteolytic digestion of intact antibodies (see, e.g., Morimoto et al., 1992, J. Biochem. Biophys. Methods 24: 107-17; and Brennan et al.. 1985, Science 229:81-83). However, these fragments can now be produced directly by recombinant host cells. For example, Fab, Fv, and scFv antibody fragments can all be expressed in and secreted from E. coli, yeast or insect cells, thus allowing the facile production of large amounts of these fragments. Antibody fragments can be isolated from the antibody phage libraries discussed above. Alternatively, Fab’-SH fragments can be directly recovered from E. coli and chemically coupled to form F(ab’)2 fragments (Carter et al., 1992, Bio / Technology 10:163-67). According to another approach, F(ab’)2 fragments can be isolated directly from recombinant host cell culture. Fab and F(ab’)2 fragments with increased in vivo half-life comprising salvage receptor binding epitope residues are described in, for example, U.S. Pat. No. 5,869,046. Other techniques for the production of antibody fragments will be apparent to the skilled practitioner. In certain embodiments, an antibody is a single chain Fv fragment (scFv) (see, e.g., WO 93 / 16185; U.S. Pat. Nos. 5,571,894 and 5,587,458). Fv and scFv have intact combining sites that are devoid of constant regions; thus, they may be suitable for reduced nonspecific binding during in vivo use. scFv fusion proteins may be constructed to yield fusion of an effector protein at either the amino or the carboxy terminus of an scFv (See, e.g., Borrebaeck ed., supra). The antibody fragment may also be a “linear antibody,” for example, as described in the references cited above. Such linear antibodies may be monospecific or multi-specific, such as bispecific.5.2.2. Humanized Antibodies

[0167] The present disclosure provides humanized antibodies that bind IL13Ra2, including human IL13Ra2. Humanized antibodies of the present disclosure may comprise one or more CDRs from a VH and / or VL disclosed herein, such as those as shown in Tables 1-3. Various methods for humanizing non-human antibodies are known in the art. For example, a humanized antibody can have one or more amino acid residues introduced into it from a source that is non-human. These non-human amino acid residues are often referred to as “import” residues, which are typically taken from an “import” variable domain. Humanized antibodies that bind IL13Ra2 may be produced using techniques known to those skilled in the art (Zhang et al., Molecular Immunology, 42(12): 1445-1451, 2005; Hwang et al., Methods, 36(1): 35-42, 2005; Dall’Acqua et al., Methods, 36(1): 43-60, 2005; Clark, Immunology Today, 21(8): 397-402, 2000, and U.S. Pat. Nos. 6,180,370; 6,054,927; 5,869,619; 5,861,155; 5,712,120; and 4,816,567).

[0168] In some cases, the humanized antibodies are constructed by CDR grafting, in which the amino acid sequences of the six CDRs of a VH and a VL of the parent non-human antibody (e.g., rodent) are grafted onto a human antibody framework. For example, Padlan et al. (FASEB J. 9: 133-139, 1995) determined that only about one third of the residues in the CDRs actually contact the antigen, and termed these the “specificity determining residues,” or SDRs. In the technique of SDR grafting, only the SDR residues are grafted onto the human antibody framework (see, e.g., Kashmiri et al.. Methods 36: 25-34, 2005).

[0169] The choice of human variable domains, both light and heavy, to be used in making the humanized antibodies can be important to reduce antigenicity. For example, according to the so-called “best-fit” method, the sequence of the variable domain of a non-human (e.g., rodent) antibody is screened against the entire library of known human variable-domain sequences. The human sequence which is closest to that of the rodent may be selected as the human framework for the humanized antibody (Sims et al. (1993) J. Immunol. 151 :2296; Chothia e / a / . (1987) J. Mol. Biol. 196:901). Another method uses a particular framework derived from the consensus sequence of all human antibodies of a particular subgroup of light or heavy chains. The same framework may be used for several different humanized antibodies (Carter et al. (1992) roc. Natl. Acad. Sci. USA, 89:4285; Presta e / o / . (1993) J. Immunol., 151 :2623). In some cases, the framework is derived from the consensus sequences of the most abundant human subclasses, VL6 subgroup I (VL6I) and VH subgroup III (VHIII). In another method, human germline genes are used at the source of the framework regions.

[0170] In an alternative paradigm based on comparison of CDRs, called Superhumanization, framework homology is irrelevant. The method consists of comparison of the non-human sequence with the functional human germline gene repertoire. Those genes encoding the same or closely related canonical structures to the murine sequences are then selected. Next, within the genes sharing the canonical structures with the non-human antibody, those with highest homology within the CDRs are chosen as framework donors. Finally, the non-human CDRs are grafted onto these frameworks (see, e.g., Tan et al, J. Immunol. 169: 1119-1125, 2002).

[0171] It is further generally desirable that antibodies be humanized with retention of their affinity for the antigen and other favorable biological properties. To achieve this goal, according to one method, humanized antibodies are prepared by a process of analysis of the parental sequences and various conceptual humanized products using three-dimensional models of the parental and humanized sequences. Three-dimensional immunoglobulinmodels are commonly available and are familiar to those skilled in the art. Computer programs are available which illustrate and display probable three-dimensional conformational structures of selected candidate immunoglobulin sequences. These include, for example, WAM (Whitelegg and Rees, Protein Eng. 13: 819-824, 2000), Modeller (Sali and Blundell, J. Mol. Biol. 234: 779-815, 1993), and Swiss PDB Viewer (Guex and Peitsch, Electrophoresis 18: 2714-2713, 1997). Inspection of these displays permits analysis of the likely role of the residues in the functioning of the candidate immunoglobulin sequence, e.g., the analysis of residues that influence the ability of the candidate immunoglobulin to bind its antigen. In this way, framework residues can be selected and combined from the recipient and import sequences so that the desired antibody characteristic, such as increased affinity for the target antigen(s), is achieved. In general, the hypervariable region residues are directly and most substantially involved in influencing antigen binding.

[0172] Another method for antibody humanization is based on a metric of antibody humanness termed Human String Content (HSC). This method compares the mouse sequence with the repertoire of human germline genes and the differences are scored as HSC. The target sequence is then humanized by maximizing its HSC rather than using a global identity measure to generate multiple diverse humanized variants. See, e.g., Lazar et al., Mol. Immunol. 44: 1986-1998, 2007.

[0173] In addition to the methods described above, empirical methods may be used to generate and select humanized antibodies. These methods include those that are based upon the generation of large libraries of humanized variants and selection of the best clones using enrichment technologies or high throughput screening techniques. Antibody variants may be isolated from phage, ribosome and yeast display libraries as well as by bacterial colony screening (see, e.g., Hoogenboom, Nat. Biotechnol. 23: 1105-1116, 2005; Dufner et al., Trends Biotechnol. 24: 523-529, 2006; Feldhaus et al, Nat. BiotechnoL 21 : 163-70, 2003; Schlapschy et al., Protein Eng. Des. SeL 17: 847-60, 2004).

[0174] In the framework library approach, a collection of residue variants are introduced at specific positions in the framework followed by selection of the library to select the framework that best supports the grafted CDR. The residues to be substituted may include some or all of the “Vernier” residues identified as potentially contributing to CDR structure (see, e.g., Foote and Winter, J. Mol. Biol. 224: 487-499, 1992), or from the more limited set of target residues identified by Baca et al. (J. Biol. Chem. 272: 10678-10684, 1997).

[0175] In framework shuffling, whole frameworks are combined with the non-human CDRs instead of creating combinatorial libraries of selected residue variants (see, e.g.,Dall’ Acqua et al., Methods 36: 43-60, 2005). The libraries may be screened for binding in a two-step selection process, first humanizing VL, followed by VH. Alternatively, a one-step framework shuffling process may be used. Such a process has been shown to be more efficient than the two-step screening, as the resulting antibodies exhibited improved biochemical and physico-chemical properties including enhanced expression, increased affinity and thermal stability (see, e.g., Damschroder et al., Mol. Immunol. 44: 3049-60, 2007).

[0176] The “humaneering” method is based on experimental identification of essential minimum specificity determinants (MSDs) and is based on sequential replacement of nonhuman fragments into libraries of human frameworks and assessment of binding. It begins with regions of the CDR3 of non-human VH and VL chains and progressively replaces other regions of the non-human antibody into the human frameworks, including the CDR1 and CDR2 of both VH and VL. This methodology typically results in epitope retention and identification of antibodies from multiple sub-classes with distinct human V-segment CDRs. Humaneering allows for isolation of antibodies that are 91-96 % homologous to human germline gene antibodies. See, e.g., Alfenito, Cambridge Healthtech Institute’s Third Annual PEGS, The Protein Engineering Summit, 2007.

[0177] The "human engineering" method involves altering a non-human antibody or antibody fragment, such as a mouse or chimeric antibody or antibody fragment, by making specific changes to the amino acid sequence of the antibody so as to produce a modified antibody with reduced immunogenicity in a human that nonetheless retains the desirable binding properties of the original non-human antibodies. Generally, the technique involves classifying amino acid residues of a non-human (e.g., mouse) antibody as “low risk”, “moderate risk”, or “high risk” residues. The classification is performed using a global risk / reward calculation that evaluates the predicted benefits of making a particular substitution (e.g., for immunogenicity in humans) against the risk that the substitution will affect the resulting antibody’s folding and / or are substituted with human residues. The particular human amino acid residue to be substituted at a given position (e.g., low or moderate risk) of a non-human (e.g., mouse) antibody sequence can be selected by aligning an amino acid sequence from the non-human antibody’s variable regions with the corresponding region of a specific or consensus human antibody sequence. The amino acid residues at low or moderate risk positions in the non-human sequence can be substituted for the corresponding residues in the human antibody sequence according to the alignment. Techniques for making human engineered proteins are described in greater detail inStudnicka et aL, Protein Engineering, 7: 805-814 (1994), U.S. Pat. Nos. 5,766,886, 5,770,196, 5,821,123, and 5,869,619, and WO 93 / 11794.5.2.3. Antibody Variants

[0178] Modifications of the antibodies that bind to IL13Ra2 described herein are contemplated. For example, it may be desirable to optimize the binding affinity and / or other biological properties of the antibody, including but not limited to specificity, thermostability, expression level, effector functions, glycosylation, reduced immunogenicity, or solubility. Thus, it is contemplated that variants of the antibodies that bind to IL13Ra2 described herein can be prepared and are included in the present disclosure. In some embodiments, antibody variants are antibodies with amino acid sequence variations as compared with the original antibody, for example, substitution, deletion, or insertion of one or more amino acid(s), as described above. For example, variations may be a substitution, deletion, or insertion of one or more codons encoding the antibody or polypeptide that results in a change in the amino acid sequence (e.g., a conservative substitution) as compared with the original antibody or polypeptide. Sites of interest for substitutional mutagenesis include the CDRs, FRs and / or constant regions. For example, antibody variants can be prepared by introducing appropriate nucleotide changes into the encoding DNA, and / or by synthesis of the desired antibody or polypeptide. Those skilled in the art who appreciate that amino acid changes may alter post- translational processes of the antibody.Chemical Modifications

[0179] Other exemplary modifications include chemical modifications, for example, by the covalent attachment of any type of molecule to the antibody. Antibody derivatives may include antibodies that have been chemically modified, for example, by glycosylation, acetylation, pegylation, phosphorylation, amidation, derivatization by known protecting / blocking groups, proteolytic cleavage, linkage to a cellular ligand or other protein, or conjugation to one or more immunoglobulin domains (e.g., Fc or a portion of an Fc). Any of numerous chemical modifications may be carried out by known techniques, including, but not limited to, specific chemical cleavage, acetylation, formulation, metabolic synthesis of tunicamycin, etc. Additionally, the antibody may contain one or more non-classical amino acids.

[0180] In some embodiments, an antibody provided herein is altered to increase or decrease the extent to which the antibody is glycosylated. Addition or deletion of glycosylation sites toan antibody may be conveniently accomplished by altering the amino acid sequence such that one or more glycosylation sites is created or removed.

[0181] When the antibody provided herein is fused to an Fc region, the carbohydrate attached thereto may be altered. Native antibodies produced by mammalian cells typically comprise a branched, biantennary oligosaccharide that is generally attached by an N-linkage to Asn297 of the CH2 domain of the Fc region. See, e.g., Wright et al. TIBTECH 15:26-32 (1997). The oligosaccharide may include various carbohydrates, e.g., mannose, N-acetyl glucosamine (GlcNAc), galactose, and sialic acid, as well as a fucose attached to a GlcNAc in the “stem” of the biantennary oligosaccharide structure. In some embodiments, modifications of the oligosaccharide in the binding molecules provided herein may be made in order to create variants with certain improved properties.

[0182] In other embodiments, when the antibody provided herein is fused to an Fc region, antibody variants provided herein may have a carbohydrate structure that lacks fucose attached (directly or indirectly) to said Fc region. For example, the amount of fucose in such antibody may be from 1% to 80%, from 1% to 65%, from 5% to 65%, or from 20% to 40%. The amount of fucose is determined by calculating the average amount of fucose within the sugar chain at Asn297, relative to the sum of all glycostructures attached to Asn297 (e.g., complex, hybrid and high mannose structures) as measured by MALDI-TOF mass spectrometry, as described in WO 2008 / 077546, for example. Asn297 refers to the asparagine residue located at about position 297 in the Fc region (EU numbering of Fc region residues); however, Asn297 may also be located about ± 3 amino acids upstream or downstream of position 297, i.e., between positions 294 and 300, due to minor sequence variations in antibodies. Such fucosylation variants may have improved ADCC function. See, e.g., U.S. Pat. Publ. Nos. 2003 / 0157108 and 2004 / 0093621. Examples of publications related to “defucosylated” or “fucose-deficient” antibody variants include: U.S. Pat. Publ. No. 2003 / 0157108; WO 2000 / 61739; WO 2001 / 29246; U.S. Pat. Publ. No. 2003 / 0115614; U.S. Pat. Publ. No. 2002 / 0164328; U.S. Pat. Publ. No. 2004 / 0093621; U.S. Pat. Publ. No.2004 / 0132140; U.S. Pat. Publ. No. 2004 / 0110704; U.S. Pat. Publ. No. 2004 / 0110282; U.S. Pat. Publ. No. 2004 / 0109865; WO 2003 / 085119; WO 2003 / 084570; WO 2005 / 035586; WO 2005 / 035778; W02005 / 053742; W02002 / 031140; Okazaki et al. J. Mol. Biol. 336: 1239- 1249 (2004); Yamane-Ohnuki et al. Biotech. Bioeng. 87: 614 (2004). Examples of cell lines capable of producing defucosylated antibodies include Lecl3 CHO cells deficient in protein fucosylation (Ripka et al. Arch. Biochem. Biophys. 249:533-545 (1986); U.S. Pat. Publ. No. 2003 / 0157108; and WO 2004 / 056312, and knockout cell lines, such as alpha-1,6-fucosyltransferase gene, FUT8, knockout CHO cells (see, e.g., Yamane-Ohnuki et al. Biotech. Bioeng. 87: 614 (2004); Kanda, Y. et al., Biotechnol. Bioeng., 94(4):680-688 (2006); and W02003 / 085107).

[0183] The binding molecules comprising an antibody provided herein are further provided with bisected oligosaccharides, e.g., in which a biantennary oligosaccharide attached to the Fc region is bisected by GlcNAc. Such variants may have reduced fucosylation and / or improved ADCC function. Examples of such variants are described, e.g., in WO 2003 / 011878 (Jean-Mairet etal.y, U.S. Pat. No. 6,602,684 (Umana et al.y, and U.S. Pat. Publ. No. 2005 / 0123546 (Umana et al.y Variants with at least one galactose residue in the oligosaccharide attached to the Fc region are also provided. Such variants may have improved CDC function. Such variants are described, e.g., in WO 1997 / 30087; WO 1998 / 58964; and WO 1999 / 22764.

[0184] In molecules that comprise the present antibody and an Fc region, one or more amino acid modifications may be introduced into the Fc region, thereby generating an Fc region variant. The Fc region variant may comprise a human Fc region sequence (e.g., a human IgGl, IgG2, IgG3 or IgG4 Fc region) comprising an amino acid modification (e.g., a substitution) at one or more amino acid positions.

[0185] In some embodiments, the present application contemplates variants that possess some but not all effector functions, which make it a desirable candidate for applications in which the half-life of the binding molecule in vivo is important yet certain effector functions (such as complement and ADCC) are unnecessary or deleterious. In vitro and / or in vivo cytotoxicity assays can be conducted to confirm the reduction / depletion of CDC and / or ADCC activities. For example, Fc receptor (FcR) binding assays can be conducted to ensure that the binding molecule lacks FcyR binding (hence likely lacking ADCC activity), but retains FcRn binding ability. Non-limiting examples of in vitro assays to assess ADCC activity of a molecule of interest are described in U.S. Pat. No. 5,500,362 (see, e.g., 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); U.S. Pat. No. 5,821,337 (see Bruggemann, M. et al., J. Exp. Med. 166: 1351-1361 (1987)). Alternatively, non-radioactive assay methods may be employed (see, for example, ACTI™ non-radioactive cytotoxicity assay for flow cytometry (CellTechnology, Inc. Mountain View, CA; and CYTOTOX 96® non-radioactive cytotoxicity assay (Promega, Madison, WI). Useful effector cells for such assays include peripheral blood mononuclear cells (PBMC) and Natural Killer (NK) cells. Alternatively, oradditionally, ADCC activity of the molecule of interest may be assessed in vivo, e.g., in an animal model such as that disclosed in Clynes et al. Proc. Nat ’I Acad. Sci. USA 95:652-656 (1998). Clq binding assays may also be carried out to confirm that the antibody is unable to bind Clq and hence lacks CDC activity. See, e.g., Clq and C3c binding ELISA in WO 2006 / 029879 and WO 2005 / 100402. To assess complement activation, a CDC assay may be performed (see, for example, Gazzano- Santoro et al., J. Immunol. Methods 202: 163 (1996); Cragg, M.S. et al., Blood 101 : 1045-1052 (2003); and Cragg, M.S. and M.J. Glennie, Blood 103:2738-2743 (2004)). FcRn binding and in vivo clearance / half-life determinations can also be performed using methods known in the art (see, e.g., Petkova, S.B. et al, Int’l. Immunol. 18(12): 1759-1769 (2006)).

[0186] Binding molecules with reduced effector function include those with substitution of one or more of Fc region residues 238, 265, 269, 270, 297, 327 and 329 (U.S. Pat. No. 6,737,056). Such Fc mutants include Fc mutants with substitutions at two or more of amino acid positions 265, 269, 270, 297 and 327, including the so-called “DANA” Fc mutant with substitution of residues 265 and 297 to alanine (US Patent No. 7,332,581).

[0187] Certain variants with improved or diminished binding to FcRs are described. (See, e.g., U.S. Pat. No. 6,737,056; WO 2004 / 056312, and Shields et al., J. Biol. Chem. 9(2): 6591- 6604 (2001).)

[0188] In some embodiments, a variant comprises an Fc region with one or more amino acid substitutions which improve ADCC, e.g., substitutions at positions 298, 333, and / or 334 of the Fc region (EU numbering of residues). In some embodiments, alterations are made in the Fc region that result in altered (e.g., either improved or diminished) Clq binding and / or Complement Dependent Cytotoxicity (CDC), e.g., as described in U.S. Pat. No. 6,194,551, WO 99 / 51642, and Idusogie et al. J. Immunol. 164: 4178-4184 (2000).

[0189] Binding molecules with increased half-lives and improved binding to the neonatal Fc receptor (FcRn), which is responsible for the transfer of maternal IgGs to the fetus (Guyer et al., J. Immunol. 117:587 (1976) and Kim et al., J. Immunol. 24:249 (1994)), are described in US2005 / 0014934A1 (Hinton et al.). Those molecules comprise an Fc region with one or more substitutions therein which improve binding of the Fc region to FcRn. Such Fc variants include those with substitutions at one or more of Fc region residues: 238, 256, 265, 272, 286, 303, 305, 307, 311, 312, 317, 340, 356, 360, 362, 376, 378, 380, 382, 413, 424 or 434, e.g., substitution of Fc region residue 434 (US Patent No. 7,371,826). See also Duncan & Winter, Nature 322:738-40 (1988); U.S. Pat. No. 5,648,260; U.S. Pat. No. 5,624,821; and WO 94 / 29351 concerning other examples of Fc region variants.

[0190] In some embodiments, it may be desirable to create cysteine engineered antibodies, in which one or more residues of an antibody are substituted with cysteine residues. In some embodiments, the substituted residues occur at accessible sites of the antibody. By substituting those residues with cysteine, reactive thiol groups are thereby positioned at accessible sites of the antibody and may be used to conjugate the antibody to other moieties, such as drug moieties or linker-drug moieties, to create an immunoconjugate, as described further herein.

[0191] Other known covalent modifications of antibodies are included within the scope of the present disclosure. Covalent modifications include reacting targeted amino acid residues of an antibody with an organic derivatizing agent that is capable of reacting with selected side chains or the N- or C- terminal residues of the antibody. Other modifications include deamidation of glutaminyl and asparaginyl residues to the corresponding glutamyl and aspartyl residues, respectively, hydroxylation of proline and lysine, phosphorylation of hydroxyl groups of seryl or threonyl residues, methylation of the a-amino groups of lysine, arginine, and histidine side chains (see, e.g., Creighton, Proteins: Structure and Molecular Properties 79-86 (1983)), acetylation of the N-terminal amine, and amidation of any C- terminal carboxyl group.

[0192] The antibody that binds to IL13Ra2 of the present disclosure may also be modified to form chimeric molecules comprising the antibody that binds to IL13Ra2 fused or conjugated to another, heterologous polypeptide or amino acid sequence or a small molecule compound, for example, an immune activator (such as a cytokine), an epitope tag (see, e.g., Terpe, Appl. Microbiol. Biotechnol. 60:523-33 (2003)) or the Fc region of an IgG molecule (see, e.g., Aruffo, Antibody Fusion Proteins 221-42 (Chamow and Ashkenazi eds., 1999)).

[0193] Also provided herein are fusion proteins comprising the antibody that binds to IL13Ra2 of the disclosure and a heterologous polypeptide. In some embodiments, the heterologous polypeptide to which the antibody is genetically fused or chemically conjugated is useful for targeting the antibody to cells having cell surface-expressed IL13Ra2.Genetically fused or chemically conjugated antibodies are described in more detail in sections below.In vitro Affinity Maturation

[0194] In some embodiments, antibody variants having an improved property such as affinity, stability, or expression level as compared to a parent antibody may be prepared by in vitro affinity maturation. Like the natural prototype, in vitro affinity maturation is based onthe principles of mutation and selection. Libraries of antibodies are displayed on the surface of an organism (e.g., phage, bacteria, yeast, or mammalian cell) or in association (e.g., covalently or non-covalently) with their encoding mRNA or DNA. Affinity selection of the displayed antibodies allows isolation of organisms or complexes carrying the genetic information encoding the antibodies. Two or three rounds of mutation and selection using display methods such as phage display usually results in antibody fragments with affinities in the low nanomolar range. Affinity matured antibodies can have nanomolar or even picomolar affinities for the target antigen.

[0195] Phage display is a widespread method for display and selection of antibodies. The antibodies are displayed on the surface of Fd or M13 bacteriophages as fusions to the bacteriophage coat protein. Selection involves exposure to antigen to allow phage-displayed antibodies to bind their targets, a process referred to as “panning.” Phage bound to antigen are recovered and used to infect bacteria to produce phage for further rounds of selection. For review, see, for example, Hoogenboom, Methods. Mol. Biol. 178: 1-37 (2002); and Bradbury and Marks, J. Immunol. Methods 290:29-49 (2004).

[0196] In a yeast display system (see, e.g., Boder etal., Nat. Biotech. 15:553-57 (1997); and Chao et al., Nat. Protocols 1 :755-68 (2006)), the antibody may be fused to the adhesion subunit of the yeast agglutinin protein Aga2p, which attaches to the yeast cell wall through disulfide bonds to Agalp. Display of a protein via Aga2p projects the protein away from the cell surface, minimizing potential interactions with other molecules on the yeast cell wall. Magnetic separation and flow cytometry are used to screen the library to select for antibodies with improved affinity or stability. Binding to a soluble antigen of interest is determined by labeling yeast with biotinylated antigen and a secondary reagent such as streptavidin conjugated to a fluorophore. Variations in surface expression of the antibody can be measured through immunofluorescence labeling of either the hemagglutinin or c-Myc epitope tag flanking the single-chain antibody (e.g., scFv). Expression has been shown to correlate with the stability of the displayed protein, and thus antibodies can be selected for improved stability as well as affinity (see, e.g., Shusta et al., J. Mol. Biol. 292:949-56 (1999)). An additional advantage of yeast display is that displayed proteins are folded in the endoplasmic reticulum of the eukaryotic yeast cells, taking advantage of endoplasmic reticulum chaperones and quality-control machinery. Once maturation is complete, antibody affinity can be conveniently “titrated” while displayed on the surface of the yeast, eliminating the need for expression and purification of each clone. A theoretical limitation of yeast surface display is the potentially smaller functional library size than that of other display methods;however, a recent approach uses the yeast cells’ mating system to create combinatorial diversity estimated to be 1014in size (see, e.g., U.S. Pat. Publ. No. 2003 / 0186374; and Blaise et al., Gene 342:211-18 (2004)).

[0197] In ribosome display, antibody-ribosome-mRNA (ARM) complexes are generated for selection in a cell-free system. The DNA library coding for a particular library of antibodies is genetically fused to a spacer sequence lacking a stop codon. This spacer sequence, when translated, is still attached to the peptidyl tRNA and occupies the ribosomal tunnel, and thus allows the protein of interest to protrude out of the ribosome and fold. The resulting complex of mRNA, ribosome, and protein can bind to surface-bound ligand, allowing simultaneous isolation of the antibody and its encoding mRNA through affinity capture with the ligand. The ribosome-bound mRNA is then reverse transcribed back into cDNA, which can then undergo mutagenesis and be used in the next round of selection (see, e.g., Fukuda et al., Nucleic Acids Res. 34:el27 (2006)). In mRNA display, a covalent bond between antibody and mRNA is established using puromycin as an adaptor molecule (Wilson et al., Proc. Natl. Acad. Sci. USA 98:3750-55 (2001)).

[0198] As these methods are performed entirely in vitro, they provide two main advantages over other selection technologies. First, the diversity of the library is not limited by the transformation efficiency of bacterial cells, but only by the number of ribosomes and different mRNA molecules present in the test tube. Second, random mutations can be introduced easily after each selection round, for example, by non-proofreading polymerases, as no library must be transformed after any diversification step. In some embodiments, mammalian display systems may be used.

[0199] Diversity may also be introduced into the CDRs of the antibody libraries in a targeted manner or via random introduction. The former approach includes sequentially targeting all the CDRs of an antibody via a high or low level of mutagenesis or targeting isolated hot spots of somatic hypermutations (see, e.g., Ho et al, J. Biol. Chem. 280:607-17 (2005)) or residues suspected of affecting affinity on experimental basis or structural reasons. Diversity may also be introduced by replacement of regions that are naturally diverse via DNA shuffling or similar techniques (see, e.g., Lu et al., J. Biol. Chem. 278:43496-507 (2003); U.S. Pat. Nos. 5,565,332 and 6,989,250). Alternative techniques target hypervariable loops extending into framework-region residues (see, e.g., Bond et al, J. Mol. Biol. 348:699- 709 (2005)) employ loop deletions and insertions in CDRs or use hybridization-based diversification (see, e.g., U.S. Pat. Publ. No. 2004 / 0005709). Additional methods of generating diversity in CDRs are disclosed, for example, in U.S. Pat. No. 7,985,840. Furthermethods that can be used to generate antibody libraries and / or antibody affinity maturation are disclosed, e.g., in U.S. Pat. Nos. 8,685,897 and 8,603,930, and U.S. Publ. Nos. 2014 / 0170705, 2014 / 0094392, 2012 / 0028301, 2011 / 0183855, and 2009 / 0075378, each of which is incorporated herein by reference.

[0200] Screening of the libraries can be accomplished by various techniques known in the art. For example, antibodies can be immobilized onto solid supports, columns, pins, or cellulose / poly (vinylidene fluoride) membranes / other filters, expressed on host cells affixed to adsorption plates or used in cell sorting, or conjugated to biotin for capture with streptavidin-coated beads or used in any other method for panning display libraries.

[0201] For reviews of in vitro affinity maturation methods, see, e.g., Hoogenboom, Nature Biotechnology 23: 1105-16 (2005); Quiroz and Sinclair, Revista Ingeneria Biomedia 4:39-51 (2010); and references therein.

[0202] An antibody internalization assay may be used to determine receptor-mediated endocytosis when binding to an antibody. In some embodiments, the efficacy of certain antibody-based therapeutics depends on antibody internalization process. In some embodiments, an antibody internalization assay examines the rate and extent of antibody internalization in order to evaluate the antibody’s ability of delivering treatments to sites or cells of interest. A non-limiting exemplary assay is briefly described below. Target cells of interest are seeded at an appropriate seeding density (e.g., in a 96-well U-bottom plate), and a tested antibody is labelled with a signal reporting reagent, for example, fluorescent compounds, Horseradish peroxidase (HRP) reagent, radiolabeled compounds, or biotin. Then the tested antibody and the target cells are incubated at an appropriate molar ratio. Following the incubation, unbound antibodies are removed by wash. The cells can be left on ice or incubated at 37°C for a period of time to facilitate internalization. The cells may then be incubated for a period of time in the presence of a stop reagent to inhibit internalization. Subsequently, the cells are washed and incubated with the signal developing reagent. The final signal can be studied using plate reader or imaging instrument and an analytical software. For example, mean fluorescence intensity (MFI) of the cells can be measured using a flow cytometer, and MFI reduction can represent antibody internalization, antibody dissociation or a combination of both. Cell imaging can be scanned and acquired to analyze the signal intensity, size and shape. Alternatively, the cells are lysed, releasing internalized antibody. This antibody is then captured in a microtiter well plate coated with specific antigen against which the antibody was raised. Bound antibody in the well is detected using an alkaline phosphatase or HRP-conjugated secondary antibody and a chromogenic substrate.Alternative detectable labels for the antibody and means for detecting internalized labeled antibody will be obvious to those skilled in the art upon this disclosure. Any methods known in the art to determine antibody internalization can be used in the present disclosure.5.2.4. Other Binding Agents Comprising the Antibodies

[0203] In some embodiments, the antibody or fragment thereof provided herein is a part of a larger binding agent. Non-limiting exemplary binding agents comprising the antibody or fragment provided herein are described below.

[0204] The present disclosure provides IL13Ra2 binding agents (e.g., antibodies) with a masking moiety and / or cleavable moiety in which one or more of the IL13Ra2 binding domains of the IL13Ra2 binding agent (e.g., antibody) are masked (e.g., via a masking moiety) and / or activatable (e.g., via a cleavable moiety). Technologies for masking of an IL13Ra2 binding agent (e.g., an antibody) are well known in the art, including SAFEbody masking technology (see, e.g., U.S. Pat. Publ. No. 2019 / 0241886) and Probody masking technology (see, e.g., U.S. Pat. Publ. No. 2015 / 0079088). Such technologies can be used to generate an IL13Ra2 binding agent (e.g., an antibody) that is masked and / or activatable. Such masked and / or activatable IL13Ra2 binding agents (e.g., antibodies) are also useful for the preparation of conjugates, including immunoconjugates, antibody-drug conjugates (ADCs), masked ADCs and activatable ADCs (AADCs), comprising any one of the IL13Ra2 binding agents (e.g., antibodies), such as human IL13Ra2 binding agents, of the present disclosure, including those directly or indirectly linked another agent such as a drug and / or an immune activator (such as a cytokine). For example, IL13Ra2 binding agents (e.g., antibodies), such as human IL13Ra2 binding agents, of the present disclosure may be covalently bound by a synthetic linker to one or more agents such as drugs and / or immune activators (such as cytokines).

[0205] If desired, an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, is linked or conjugated (directly or indirectly) to a moiety with effector function, such as cytotoxic activity (e.g., a chemotherapeutic moiety or a radioisotope), immune recruitment or modulating activity. Moieties that are linked or conjugated (directly or indirectly) include drugs that are cytotoxic (e.g., toxins such as aurostatins) or non-cytotoxic, e.g., signal transduction modulators such as kinases or masking moieties that mask one or more binding domains of an IL13Ra2 binding agent (e.g., antibody), or cleavable moieties that allow for activating an IL13Ra2 binding agent by cleaving off a cleavable moiety to unmask one or more binding domains of an IL13Ra2 binding agent (e.g., antibody) in the tumor microenvironment in the form of maskedconjugates. Moieties that promote immune recruitment can include other antigen-binding agents, such as viral proteins that bind selectively to cells of the innate and / or adaptive immune system. Alternatively or in addition, an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, is optionally linked or conjugated (directly or indirectly) to a moiety that facilitates isolation from a mixture (e.g., a tag) or a moiety with reporter activity (e.g., a detection label or reporter protein). It will be appreciated that the features of an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, described herein extend also to a polypeptide comprising an IL13Ra2 binding agent fragment.

[0206] In some embodiments, IL13Ra2 binding agents (e.g., antibodies), including IL13Ra2 binding agents, described herein which bind to human IL13Ra2, may be linked or conjugated (directly or indirectly) to a polypeptide, which can result in the generation of an activatable antibody. In some embodiments, an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, is linked or conjugated (directly or indirectly) to an additional agent. In some embodiments, the additional agent is a drug, resulting in an ADC or an AADC when the antibody of the ADC comprises a masking moiety and a cleavable moiety.

[0207] In some embodiments, IL13Ra2 binding agents (e.g., antibodies), including human IL13Ra2 binding agents, described herein are conjugated or recombinantly linked (directly or indirectly) to a therapeutic agent (e.g., a cytotoxic agent or a cytokine) or to a diagnostic or detectable agent. The conjugated or recombinantly linked antibodies, including masked or activatable conjugates, can be useful, for example, for treating or preventing a disease, disorder or condition such as an IL 13Ra2 -mediated disease, disorder or condition. The conjugated or recombinantly linked IL13Ra2 binding agents (e.g., antibodies), including masked or activatable conjugates, can be useful, for example, for monitoring or prognosing the onset, development, progression, and / or severity of an IL13Ra2-mediated disease, disorder or condition.

[0208] Such diagnosis and detection can be accomplished, for example, by coupling an IL13Ra2 binding agent (e.g., an antibody) to detectable substances including, for example: enzymes, including, but not limited to, horseradish peroxidase, alkaline phosphatase, betagalactosidase, or acetylcholinesterase; prosthetic groups, including, but not limited to, streptavidin / biotin or avidin / biotin; fluorescent materials, including, but not limited to, umbelliferone, fluorescein, fluorescein isothiocynate, rhodamine, dichlorotriazinylamine fluorescein, dansyl chloride, or phycoerythrin; luminescent materials, including, but notlimited to, luminol; bioluminescent materials, including, but not limited to, luciferase, luciferin, or aequorin; chemiluminescent material, including, but not limited to, an acridinium based compound or a HALOTAG; radioactive materials, including, but not limited to, iodine (131I,125I,123I, and121I), carbon (14C), sulfur (35S), tritium (3H), indium (115In,113In,112In, andH 1In), technetium (99Tc), thallium (201Ti), gallium (68Ga and67Ga), palladium (103Pd), molybdenum (99Mo), xenon (133Xe), fluorine (18F),153Sm,177Lu,159Gd,149Pm,140La,175Yb,166HO,90Y,47SC,186Re,188Re,142Pr,105Rh,97Ru,68Ge,57Co,65Zn,85Sr,32P,153Gd,169Yb,51Cr,54Mn,75Se,113Sn, or117Sn; positron emitting metals using various positron emission tomographies; and non-radioactive paramagnetic metal ions.

[0209] Also described herein are IL13Ra2 binding agents (e.g., antibodies) that are recombinantly linked or conjugated (covalent or non-covalent conjugations, directly or indirectly) to a heterologous protein or polypeptide or fragment thereof, for example, to a polypeptide (e.g., of about 10, about 20, about 30, about 40, about 50, about 60, about 70, about 80, about 90, or about 100 amino acids) to generate fusion proteins, as well as uses thereof. In particular, described herein are fusion proteins comprising an antigen-binding fragment of an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, described herein (e.g., comprising CDR1, CDR2, and / or CDR3 of VH and / or VL) and a heterologous protein, polypeptide, or peptide. In some embodiments, the heterologous protein, polypeptide, or peptide that an IL13Ra2 binding agent (e.g., an antibody) is linked to is useful for targeting the IL13Ra2 binding agent to a particular cell (e.g., an IL13Ra2-expressing cell, including an cancer cell). Other non-limiting heterologous protein, polypeptide, or peptide that an IL13Ra2 binding agent (e.g., an antibody) is linked to can be useful as an internalization signal or engaging a tumor cell with an immune cell.

[0210] Moreover, IL13Ra2 binding agents (e.g., antibodies), including human IL13Ra2 binding agents, described herein can be linked (directly or indirectly) to marker or “tag” sequences, such as a peptide, to facilitate purification. In some embodiments, the marker or tag amino acid sequence is a hexa-histidine peptide, such as the tag provided in a pQE vector (see, e.g., QIAGEN, Inc.), among others, many of which are commercially available. For example, as described in Gentz et al., 1989, Proc. Natl. Acad. Sci. USA 86:821-24, hexahistidine provides for convenient purification of a fusion protein. Other peptide tags useful for purification include, but are not limited to, the hemagglutinin (“HA”) tag, which corresponds to an epitope derived from the influenza hemagglutinin protein (Wilson et al., 1984, Cell 37:767-78), and the “FLAG” tag.

[0211] Methods for linking or conjugating (directly or indirectly) moieties (including polypeptides) to antibodies are well known in the art, any one of which can be used to make an antibody-drug conjugate or fusion protein described herein.

[0212] In some embodiments, an IL13Ra2 binding agent (e.g., an antibody) described herein is a fusion protein. The term “fusion protein” as used herein refers to a polypeptide that comprises an amino acid sequence of a binding agent (e.g., an antibody) and an amino acid sequence of a heterologous polypeptide or protein (e.g., a polypeptide or protein not normally a part of the antibody). In certain embodiments, the fusion protein retains the biological activity of an IL13Ra2 binding agent. In certain embodiments, the fusion protein comprises an IL13Ra2 antibody VH region, VL region, VH CDR (one, two or three VH CDRs), and / or VL CDR (one, two or three VL CDRs), wherein the fusion protein binds to an IL13Ra2 epitope, an IL13Ra2 fragment and / or an IL13Ra2 polypeptide. In some embodiments, a fusion protein comprises a VH or heavy chain of an IL13Ra2 antibody, a VL or light chain of an IL13Ra2 antibody, separated by a linker, such as a cleavable linker.

[0213] Fusion proteins may be generated, for example, through the techniques of geneshuffling, motif-shuffling, exon-shuffling, and / or codon-shuffling (collectively referred to as “DNA shuffling”). DNA shuffling may be employed to alter the activities of IL13Ra2 binding agents (e.g., antibodies), including human IL13Ra2 binding agents, as described herein, including, for example, IL13Ra2 binding agents with higher affinities and lower dissociation rates (see, e.g., U.S. Pat. Nos. 5,605,793; 5,811,238; 5,830,721; 5,834,252; and 5,837,458; Patten el al., 1997, Curr. Opinion Biotechnol. 8:724-33; Harayama, 1998, Trends Biotechnol. 16(2):76-82; Hansson etal., 1999, J. Mol. Biol. 287:265-76; and Lorenzo and Blasco, 1998, Biotechniques 24(2):308- 13). In some embodiments, IL13Ra2 binding agents, including human IL13Ra2 binding agents, may be altered by being subjected to random mutagenesis by error-prone PCR, random nucleotide insertion, or other methods prior to recombination. A polynucleotide encoding an IL13Ra2 binding agent described herein may be recombined with one or more components, motifs, sections, parts, domains, fragments, etc. of one or more heterologous molecules.

[0214] IL13Ra2 binding agents (e.g, antibodies), including human IL13Ra2 binding agents, described herein may also be attached to solid supports, which are useful for immunoassays or purification of the target antigen. Such solid supports include, but are not limited to, glass, cellulose, polyacrylamide, nylon, polystyrene, polyvinyl chloride, or polypropylene.

[0215] IL13Ra2 binding agents (e.g., antibodies), including human IL13Ra2 binding agents, described herein can also be linked or conjugated (directly or indirectly) to a second antibody to form an antibody heteroconjugate.

[0216] The linker may be a “cleavable moiety” facilitating release of the linked or conjugated agent in a cell, but non-cleavable linkers are also contemplated herein. Linkers for use in conjugates (e.g., ADCs or AADCs) of the present disclosure include, without limitation, acid labile linkers, disulfide-containing linkers, peptidase-sensitive linkers, photolabile linkers, dimethyl linkers, thioether linkers, or hydrophilic linkers designed to evade multidrug transporter-mediated resistance.

[0217] Conjugates of an antibody and agent, including wherein the agent is a drug for the preparation of ADC or an AADC, may be made using a variety of bifunctional protein coupling agents.

[0218] The present disclosure further contemplates conjugates of antibodies and agents, including wherein the agent is a drug for the preparation of ADC or AADC, may be prepared using any suitable methods as disclosed in the art (see, e.g., Bioconjugate Techniques (Hermanson ed., 2d ed. 2008)).

[0219] Conventional conjugation strategies for antibodies and agents, including wherein the agent is a drug for the preparation of ADC or AADC, have been based on random conjugation chemistries involving the 8-amino group of Lys residues or the thiol group of Cys residues, which results in heterogeneous conjugates. Recently developed techniques allow site-specific conjugation to antibodies, resulting in homogeneous loading and avoiding conjugate subpopulations with altered antigen-binding or pharmacokinetics. These include engineering of “thiomabs” comprising cysteine substitutions at positions on the heavy and light chains that provide reactive thiol groups and do not disrupt immunoglobulin folding and assembly or alter antigen binding (see, e.g., Junutula et al., 2008, J. Immunol. Meth. 332: 41- 52; and Junutula et al., 2008, Nature Biotechnol. 26:925-32). In another method, selenocysteine is co-translationally inserted into an antibody sequence by recoding the stop codon UGA from termination to selenocysteine insertion, allowing site specific covalent conjugation at the nucleophilic selenol group of selenocysteine in the presence of the other natural amino acids (see, e.g., Hofer et al., 2008, Proc. Natl. Acad. Sci. USA 105: 12451-56; and Hofer et al., 2009, Biochemistry 48(50): 12047-57).

[0220] In some embodiments, an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, described herein is conjugated to an agent, for example, an immune activator or a cytotoxic agent. In some embodiments, an IL13Ra2 binding agent(e.g., an antibody), including a human IL13Ra2 binding agent, disclosed herein can be optionally conjugated with one or more cytotoxic agent(s) disclosed herein or known in the art in order to generate an ADC or AADC. In some embodiments, the cytotoxic agent is a chemotherapeutic. In some embodiments, the cytotoxic agent is an enzymatically active toxin of bacterial, fungal, plant, or animal origin, or fragments thereof. In some embodiments, the cytotoxic agent is a radioisotope to produce a radioconjugate or a radioconjugated agent. Conjugates of a polypeptide or molecule and one or more small molecule toxins. Conjugates of a polypeptide or molecule and cytotoxic agent are made using a variety of bifunctional protein-coupling agents .

[0221] In other embodiments, an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, described herein is conjugated to a drug such as a signal transduction modulator, a pro-apoptotic agent, a mitotic inhibitor, an anti-tumor antibiotic, an immunomodulating agent, a nucleic acid for gene therapy, an alkylating agent, an anti- angiogenic agent, an anti-metabolite, a boron-containing agent, a chemoprotective agent, a hormone agent, an anti-hormone agent, a corticosteroid, a photoactive therapeutic agent, an oligonucleotide, a radionuclide agent, a radiosensitizer, a topoisomerase inhibitor, such as camptothecin or an analog thereof, and a tyrosine kinase inhibitor.

[0222] IL13Ra2 binding agents (e.g., antibodies), including human IL13Ra2 binding agents, described herein may be monospecific, bispecific, trispecific or of greater multispecificity. Such agents may include monospecific or multispecific antibodies. Multispecific antibodies, such as bispecific antibodies, are monoclonal antibodies that have binding specificities for at least two different targets (e.g., antigens) or two different epitopes on the same target (e.g., a bispecific antibody directed to IL13Ra2 with a first binding domain for a first epitope of an IL13Ra2, and a second binding domain for a second epitope of IL13Ra2). In some embodiments, the monospecific and multispecific (e.g., bispecific) antibodies can be constructed based on the sequences of the antibodies described herein, e.g., the CDR sequences listed in Tables 1-3. In some embodiments, the multispecific antibodies described herein are bispecific antibodies. In some embodiments, bispecific antibodies are mouse, chimeric, human or humanized antibodies.

[0223] In some embodiments, one of the binding specificities of the multispecific antibody is for IL13Ra2 and the other is for any other target (e.g., antigen). In some embodiments, a multispecific (e.g., bispecific) antibody can comprise more than one target (e.g., antigen) binding domain, in which different binding domains are specific for different targets (e.g., a first binding domain that binds to IL13Ra2 and a second binding domain that binds anothertarget (e.g., antigen). In some embodiments, the second target is an immune checkpoint regulator (e.g., a negative checkpoint regulator). In some embodiments, the second target is expressed on an immune cell. In some embodiments, the second target is expressed on a tumor or cancer cell.

[0224] In some embodiments, multispecific (e.g., bispecific) antibody molecules can bind than one (e.g., two or more) epitopes on the same target (e.g., antigen).

[0225] Methods for making multispecific antibodies are known in the art, such as, by coexpression of two immunoglobulin heavy chain-light chain pairs, where the two heavy chains have different specificities (see, e.g., Milstein and Cuello, 1983, Nature 305:537-40). For further details of generating multispecific antibodies (e.g., bispecific antibodies), see, for example, Bispecific Antibodies (Kontermann ed., 2011).

[0226] Exemplary structures of multispecific antibodies are known in the art and are further described in Weidle et al., 2013, Cancer Genomics & Proteomics 10: 1-18; Brinkman et al., 2017, MABS, 9:2, 182-212; Godar et al., 2018, Expert Opinion on Therapeutic Patents, 28:3, 251-276; and Spiess et al., 2015, Mol. Immunol. 67 95-106.

[0227] For example, bispecific antibody molecules can be classified into different structural groups: (i) bispecific immunoglobulin G (BsIgG); (ii) IgG appended with an additional antigen-binding moiety; (iii) bispecific antibody fragments; (iv) bispecific fusion proteins; and (v) bispecific antibody conjugates. As a non-limiting example, BsIgG formats can include crossMab, DAF (two-in-one), DAF (four-in-one), DutaMab, DT-IgG, knobs-in-holes common LC, knobs-in-holes assembly, charge pair, Fab-arm exchange, SEEDbody, triomab, LUZ-Y, Fcab, Kk-body, and / or orthogonal Fab.

[0228] In some embodiments, BsIgG comprises heavy chains that are engineered for heterodimerization. For example, heavy chains can be engineered for heterodimerization using a “knobs-into-holes” strategy, a SEED platform, a common heavy chain (e.g., in KZ- bodies), and use of heterodimeric Fc regions. Strategies are known in the art to avoid heavy chain pairing of homodimers in BsIgG, including knobs-into-holes, duobody, azymetric, charge pair, HA-TF, SEEDbody, and differential protein A affinity.

[0229] Another bispecific antibody format is IgG appended with an additional antigenbinding moiety. For example, monospecific IgG can be engineered to have bispecificity by appending an additional antigen-binding unit onto the monospecific IgG, e.g., at the N- or C- terminus of either the heavy or light chain. Exemplary additional antigen-binding units include single domain antibodies (e.g., variable heavy chain or variable light chain), engineered protein scaffolds, and paired antibody variable domains (e.g., single chainvariable fragments or variable fragments). Non-limiting examples of appended IgG formats include dual variable domain IgG (DVD-Ig), IgG(H)-scFv, scFv-(H)IgG, IgG(L)-scFv, scFv- (L)IgG, IgG(L,H)-Fv, IgG(H)-V, V(H)-IgG, IgG(L)-V, V(L)-IgG, KIH IgG-scFab, 2scFv- IgG, IgG-2scFv, scFv4-Ig, zybody, and DVI-IgG (four- in-one). See Spiess et al. Mol. Immunol. 67(2015):95-106. In some embodiments, an exemplary antibody format is a B- Body format for monospecific or multispecific (e.g., bispecific antibodies) as described in e.g. WO 2018 / 075692 and U.S. Pat. Publ. No. 2018 / 0118811.

[0230] Bispecific (Bs) antibody (BsAb) fragments are a format of bispecific antibody molecules that lack some or all of the antibody constant domains. For example, some BsAb lack an Fc region. In embodiments, bispecific antibody fragments include heavy and light chain regions that are connected by a peptide linker that permits efficient expression of the BsAb in a single host cell. Non-limiting examples of bispecific antibody fragments include, but are not limited to, nanobody, nanobody- HAS, BiTE, Diabody, DART, TandAb, scDiabody, scDiabody-CH3, Diabody-CH3, triple body, miniantibody, minibody, TriBi minibody, scFv-CH3 KIH, Fab-scFv, scFv-CH-CL-scFv, F(ab’)2, F(ab’)2-scFv2, scFv-KIH, Fab-scFv-Fc, tetravalent HC Ab, scDiabody-Fc, Diabody-Fc, tandem scFv-Fc, and intrabody.

[0231] Bispecific fusion proteins include antibody fragments linked to other proteins. For example, bispecific fusion proteins can be linked to other proteins to add additional specificity and / or functionality. In some embodiments, the dock-and-lock (DNL) method can be used to generate bispecific antibody molecules with higher valency. For example, bispecific antibody fusions to albumin binding proteins or human serum albumin can be extend the serum half-life of antibody fragments. In embodiments, chemical conjugation, e.g., chemical conjugation of antibodies and / or antibody fragments, can be used to create BsAb molecules. An exemplary bispecific antibody conjugate includes the CovX-body format, in which a low molecular weight drug is conjugated site-specifically to a single reactive lysine in each Fab arm or an antibody or fragment thereof. In some embodiments, the conjugation improves the serum half-life.

[0232] Methods of production of multispecific antibodies, including bispecific antibodies, are known in the art. For example, multispecific antibodies, including bispecific antibodies, can be produced by separate expression of the component antibodies in different host cells and subsequent purification / assembly or by expression of the component antibodies in a single host cell. Purification of multispecific (e.g., bispecific) antibody molecules can be performed by various methods known in the art, including affinity chromatography.

[0233] In some embodiments, IL13Ra2 binding agents (e.g., antibodies), including human IL13Ra2 binding agents, disclosed herein can be provided in any antibody format disclosed herein or known in the art. As a non-limiting example, in some embodiments, the IL13Ra2 binding agents (e.g., antibodies), including human IL13Ra2 binding agents, can be selected from Fabs-in-tandem-lg (FIT-lg); DVD-lg; hybrid hybridoma (quadroma or tetradoma); anticalin platform (Pieris); diabodies; single chain diabodies; tandem single chain Fv fragments; TandAbs, Trispecific Abs (Affimed); Darts dual affinity retargeting (Macrogenics); Bispecific Xmabs (Xencor); Bispecific T cell engagers (Bites; Amgen; 55kDa); Triplebodies; Tribody = Fab-scFv Fusion Protein multifunctional recombinant antibody derivates (CreativeBiolabs); Duobody platform (Genmab); dock and lock platform; knobs-into-holes (KIH) platform; Humanized bispecific IgG antibody (REGN1979) (Regeneron); Mab2 bispecific antibodies (F-Star); DVD-lg = dual variable domain immunoglobulin (Abbott); kappa-lambda bodies; TBTI = tetravalent bispecific tandem Ig; and CrossMab (Roche).

[0234] In some embodiments, a multispecific (e.g., bispecific) antibody disclosed herein comprises an IL13Ra2 binding domain and one or more additional binding domains that bind to one or more targets that are not IL13Ra2. In some embodiments, a multispecific (e.g., bispecific) antibody disclosed herein comprises an IL13Ra2 binding domain that comprises the VH and / or VL amino acid sequences as disclosed herein, such as those of Table 1, Table 2, or Table 3.

[0235] In some embodiments, described herein is a multispecific (e.g., bispecific) antibody comprising a binding domain which binds to IL13Ra2 that comprises VH and VL CDRs disclosed herein, such as those as set forth in Table 1, Table 2, or Table 3.

[0236] In some embodiments, the IL13Ra2 binding agent is a bispecific antibody comprising a first binding domain and a second binding domain. In yet further embodiments, the first binding domain comprises six CDRs of the antibody designated A22. In some embodiments, the first binding domain comprises six CDRs as listed in one column of Table 1. In some embodiments, the first binding domain comprises three CDRs of the heavy chain variable region as set forth in SEQ ID NO: 25 and three CDRs of the light chain variable regions as set forth in SEQ ID NO: 26. In some embodiments, the first binding domain comprises the heavy chain variable region as set forth in SEQ ID NO: 25 and the light chain variable regions as set forth in SEQ ID NO: 26. In some embodiments, the second binding domain binds to a different epitope of the first complex, and does not bind to the secondcomplex. In other preferred embodiments, the second binding domain does not bind to the first complex or the second complex.

[0237] In some embodiments, the IL13Ra2 binding agent is a bispecific antibody comprising a first binding domain and a second binding domain. In yet further embodiments, the first binding domain comprises six CDRs of the antibody designated A33. In some embodiments, the first binding domain comprises six CDRs as listed in one column of Table2. In some embodiments, the first binding domain comprises three CDRs of the heavy chain variable region as set forth in SEQ ID NO: 48 and three CDRs of the light chain variable regions as set forth in SEQ ID NO: 49. In some embodiments, the first binding domain comprises the heavy chain variable region as set forth in SEQ ID NO: 48 and the light chain variable regions as set forth in SEQ ID NO: 49. In some embodiments, the second binding domain binds to a different epitope of the first complex, and does not bind to the second complex. In other preferred embodiments, the second binding domain does not bind to the first complex or the second complex.

[0238] In some embodiments, the IL13Ra2 binding agent is a bispecific antibody comprising a first binding domain and a second binding domain. In yet further embodiments, the first binding domain comprises six CDRs of the antibody designated A52. In some embodiments, the first binding domain comprises six CDRs as listed in one column of Table3. In some embodiments, the first binding domain comprises three CDRs of the heavy chain variable region as set forth in SEQ ID NO: 73 and three CDRs of the light chain variable regions as set forth in SEQ ID NO: 74. In some embodiments, the first binding domain comprises the heavy chain variable region as set forth in SEQ ID NO: 73 and the light chain variable regions as set forth in SEQ ID NO: 74. In some embodiments, the second binding domain binds to a different epitope of the first complex, and does not bind to the second complex. In other preferred embodiments, the second binding domain does not bind to the first complex or the second complex.

[0239] In another aspect, the antibody or antigen-binding fragment thereof provided herein can be part of an engineered cell surface receptor such as a chimeric antigen receptor (CAR). Typically, a CAR comprises an extracellular domain, a transmembrane domain, and an intracellular signaling domain.

[0240] In some embodiments, provided herein is a CAR comprising an extracellular domain that comprises one or more antibody or fragment thereof provided herein. In some embodiments, the extracellular domain of a CAR provided herein comprises VH and VL CDRs disclosed herein, such as those as set forth in Table 1, Table 2, or Table 3.

[0241] The CARs of the present disclosure comprise a transmembrane domain that can be directly or indirectly fused to the extracellular antigen-binding domain. The transmembrane domain may be derived either from a natural or from a synthetic source. As used herein, a “transmembrane domain” refers to any protein structure that is thermodynamically stable in a cell membrane, preferably a eukaryotic cell membrane. Transmembrane domains compatible for use in the CARs described herein may be obtained from a naturally occurring protein. Alternatively, it can be a synthetic, non-naturally occurring protein segment, e.g., a hydrophobic protein segment that is thermodynamically stable in a cell membrane. Transmembrane domains are classified based on the three dimensional structure of the transmembrane domain. For example, transmembrane domains may form an alpha helix, a complex of more than one alpha helix, a beta-barrel, or any other stable structure capable of spanning the phospholipid bilayer of a cell.

[0242] The CARs of the present disclosure comprise an intracellular signaling domain. The intracellular signaling domain is responsible for activation of at least one of the normal effector functions of the immune effector cell expressing the CARs. The term “effector function” refers to a specialized function of a cell. Effector function of a T cell, for example, may be cytolytic activity or helper activity including the secretion of cytokines. Thus the term “cytoplasmic signaling domain” refers to the portion of a protein which transduces the effector function signal and directs the cell to perform a specialized function. While usually the entire cytoplasmic signaling domain can be employed, in many cases it is not necessary to use the entire chain. To the extent that a truncated portion of the cytoplasmic signaling domain is used, such truncated portion may be used in place of the intact chain as long as it transduces the effector function signal. The term cytoplasmic signaling domain is thus meant to include any truncated portion of the cytoplasmic signaling domain sufficient to transduce the effector function signal.

[0243] In some embodiments, the intracellular signaling domain comprises a primary intracellular signaling domain of an immune effector cell. In some embodiments, the CAR comprises an intracellular signaling domain consisting essentially of a primary intracellular signaling domain of an immune effector cell. “Primary intracellular signaling domain” refers to cytoplasmic signaling sequence that acts in a stimulatory manner to induce immune effector functions.

[0244] Many immune effector cells require co-stimulation, in addition to stimulation of an antigen-specific signal, to promote cell proliferation, differentiation and survival, as well as to activate effector functions of the cell. In some embodiments, the CAR comprises at leastone co-stimulatory signaling domain. The term “co-stimulatory signaling domain,” as used herein, refers to at least a portion of a protein that mediates signal transduction within a cell to induce an immune response such as an effector function.

[0245] The CARs of the present disclosure may comprise a hinge domain that is located between the extracellular antigen-binding domain and the transmembrane domain. A hinge domain is an amino acid segment that is generally found between two domains of a protein and may allow for flexibility of the protein and movement of one or both of the domains relative to one another. Any amino acid sequence that provides such flexibility and movement of the extracellular antigen-binding domain relative to the transmembrane domain of the effector molecule can be used.

[0246] The CARs of the present disclosure may comprise a signal peptide (also known as a signal sequence) at the N-terminus of the polypeptide. In general, signal peptides are peptide sequences that target a polypeptide to the desired site in a cell.

[0247] Other engineered transmembrane receptors comprising the antibody or fragment provided herein are also included in the present disclosure.5.3. Nucleic Acids, Vectors and Cells

[0248] Additionally provided are a nucleic acid encoding an IL13Ra2 binding agent (e.g., antibody or antibody fragment) or a fusion polypeptide as disclosed herein, a nucleic acid complementary thereto; a vector comprising a nucleic acid as disclosed herein; and a cell comprising any one or more of: an IL13Ra2 binding agent as disclosed herein, a nucleic acid as disclosed herein, or a vector as disclosed herein. In some embodiments, the cell expresses the IL13Ra2 binding agent. In some embodiments, the cell replicates the nucleic acid or the vector. In some embodiments, provided are the materials for generating IL13Ra2 binding agents, e.g., human IL13Ra2 binding agents, and fragments thereof. For example, an isolated cell may produce an IL13Ra2 binding agent (e.g., antibody or antibody fragment). In this regard, a cell (e.g., an isolated cell) may produce an antibody or fragment thereof comprising a VH and a VL as disclosed herein. In some embodiments, polynucleotides described herein may comprise one or more nucleic acid sequences encoding an IL13Ra2 binding agent (e.g., antibody or antibody fragment). In some embodiments, the polynucleotide is an isolated and / or recombinant polynucleotide. In various aspects, the isolated polynucleotide comprises a nucleotide sequence that encodes a VH and / or a VL, wherein the VH and the VL comprise complementarity determining regions (CDRs) identical to CDRs as disclosed herein.

[0249] As used herein, the term “complementary” refers to specific binding between polynucleotides based on the sequences of the polynucleotides. As used herein, a firstpolynucleotide and a second polynucleotide are complementary if they bind to each other in a hybridization assay under stringent conditions, e.g., if they produce a given or detectable level of signal in a hybridization assay. Portions of polynucleotides are complementary to each other if they follow conventional base-pairing rules, e.g., A pairs with T (or U) and G pairs with C, although small regions (e.g., fewer than about 3 bases) of mismatch, insertion, or deleted sequence may be present. The term “stringent assay conditions” refers to conditions that are compatible to produce binding pairs of nucleic acids, e.g, probes and target mRNAs, of sufficient complementarity to provide for the desired level of specificity in the assay while being generally incompatible to the formation of binding pairs between binding members of insufficient complementarity to provide for the desired specificity. The term “stringent assay conditions” generally refers to the combination of hybridization and wash conditions.

[0250] In some embodiments, one or more vectors (e.g, expression vectors) may comprise one or more polynucleotides for expression of the one or more polynucleotides in a suitable host cell. Such vectors are useful, for example, for amplifying the polynucleotides in host cells to create useful quantities thereof, and for expressing binding agents, such as antibodies or antibody fragments, using recombinant techniques.

[0251] In some embodiments, one or more vectors are expression vectors wherein one or more polynucleotides are operatively linked to one or more polynucleotides comprising expression control sequences. Autonomously replicating recombinant expression constructs such as plasmid and viral DNA vectors incorporating one or more polynucleotides encoding antibody sequences that bind IL13Ra2 are specifically contemplated. Expression control DNA sequences include promoters, enhancers, and operators, and are generally selected based on the expression systems in which the expression construct is to be utilized. Promoter and enhancer sequences are generally selected for the ability to increase gene expression, while operator sequences are generally selected for the ability to regulate gene expression. Expression constructs may also include sequences encoding one or more selectable markers that permit identification of host cells bearing the construct. Expression constructs may also include sequences that facilitate, and preferably promote, homologous recombination in a host cell. In some embodiments, expression constructs of the can also include sequences necessary for replication in a host cell.

[0252] Exemplary expression control sequences include promoter / enhancer sequences, e.g., cytomegalovirus promoter / enhancer (Lehner et al., J. Clin. Microbiol., 29: 2494-2502, 1991; Boshart et al., Cell, 41 : 521-530, 1985); Rous sarcoma virus promoter (Davis et al., Hum.Gene Ther., 4: 151, 1993); Tie promoter (Korhonen et al., Blood, 86(5): 1828-1835, 1995); simian virus 40 promoter; DRA (downregulated in adenoma; Alrefai et al., Am. J. Physiol. Gastrointest. Liver Physiol., 293: G923-G934, 2007); MCT1 (monocarboxylate transporter 1; Cuff etal., Am. J. Physiol. Gastrointet. Liver Physiol., G977-G979. 2005); and Mathl (mouse atonal homolog 1; Shroyer et aL, Gastroenterology, 132: 2477-2478, 2007), for expression in mammalian cells, the promoter being operatively linked upstream (e.g., 5’) of a polypeptide coding sequence. In another variation, the promoter is an epithelial-specific promoter or endothelial-specific promoter. Polynucleotides may also optionally include a suitable polyadenylation sequence (e.g., the SV40 or human growth hormone gene polyadenylation sequence) operably linked downstream (e.g., 3’) of the polypeptide coding sequence.

[0253] If desired, the one or more polynucleotides also optionally comprise nucleotide sequences encoding secretory signal peptides fused in frame with the polypeptide sequences. The secretory signal peptides direct secretion of the antibody polypeptides by the cells that express the one or more polynucleotides, and are cleaved by the cell from the secreted polypeptides. The one or more polynucleotides may further optionally comprise sequences whose only intended function is to facilitate large scale production of the vector. One can manufacture and administer polynucleotides for gene therapy using procedures that have been described in the literature for a variety of transgenes. See, e.g., Isner et al., Circulation, 91 : 2687-2692, 1995; and Isner et al. , Human Gene Therapy, 7: 989-1011, 1996.

[0254] In some embodiments, polynucleotides may further comprise additional sequences to facilitate uptake by host cells and expression of the antibody or fragment thereof (and / or any other peptide). In some embodiments, a “naked” transgene encoding an antibody or fragment thereof described herein (e.g., a transgene without a viral, liposomal, or other vector to facilitate transfection) is employed.

[0255] The polynucleotides of the disclosure can be in the form of RNA or in the form of DNA. DNA includes cDNA, genomic DNA, and synthetic DNA; and can be double-stranded or single-stranded, and if single stranded can be the coding strand or non-coding (anti-sense) strand. In some embodiments, the polynucleotide is in the form of cDNA. In some embodiments, the polynucleotide is a synthetic polynucleotide.

[0256] The present disclosure further relates to variants of the polynucleotides described herein, wherein the variant encodes, for example, fragments, analogs, and / or derivatives of the binding molecules of the disclosure. In certain embodiments, the present disclosure provides a polynucleotide comprising a polynucleotide having a nucleotide sequence at leastabout 75% identical, at least about 80% identical, at least about 85% identical, at least about 90% identical, at least about 95% identical, and in some embodiments, at least about 96%, 97%, 98% or 99% identical to a polynucleotide encoding the binding molecule of the disclosure. As used herein, the phrase “a polynucleotide having a nucleotide sequence at least, for example, 95% “identical” to a reference nucleotide sequence is intended to mean that the nucleotide sequence of the polynucleotide is identical to the reference sequence except that the polynucleotide sequence can include up to five point mutations per each 100 nucleotides of the reference nucleotide sequence. In other words, to obtain a polynucleotide having a nucleotide sequence at least 95% identical to a reference nucleotide sequence, up to 5% of the nucleotides in the reference sequence can be deleted or substituted with another nucleotide, or a number of nucleotides up to 5% of the total nucleotides in the reference sequence can be inserted into the reference sequence. These mutations of the reference sequence can occur at the 5' or 3' terminal positions of the reference nucleotide sequence or anywhere between those terminal positions, interspersed either individually among nucleotides in the reference sequence or in one or more contiguous groups within the reference sequence.

[0257] The polynucleotide variants can contain alterations in the coding regions, noncoding regions, or both. In some embodiments, a polynucleotide variant contains alterations which produce silent substitutions, additions, or deletions, but does not alter the properties or activities of the encoded polypeptide. In some embodiments, a polynucleotide variant comprises silent substitutions that results in no change to the amino acid sequence of the polypeptide (due to the degeneracy of the genetic code). Polynucleotide variants can be produced for a variety of reasons, for example, to optimize codon expression for a particular host (z.e., change codons in the human mRNA to those preferred by a bacterial host such as E. colt). In some embodiments, a polynucleotide variant comprises at least one silent mutation in a non-coding or a coding region of the sequence.

[0258] In some embodiments, a polynucleotide variant is produced to modulate or alter expression (or expression levels) of the encoded polypeptide. In some embodiments, a polynucleotide variant is produced to increase expression of the encoded polypeptide. In some embodiments, a polynucleotide variant is produced to decrease expression of the encoded polypeptide. In some embodiments, a polynucleotide variant has increased expression of the encoded polypeptide as compared to a parental polynucleotide sequence. In some embodiments, a polynucleotide variant has decreased expression of the encoded polypeptide as compared to a parental polynucleotide sequence.

[0259] Any suitable vectors may be used to introduce one or more polynucleotides that encode an antibody or fragment thereof into the host. Exemplary vectors that have been described include replication deficient retroviral vectors, including but not limited to lentivirus vectors (Kim et aL, J. Virol., 72(1): 811-816, 1998; Kingsman & Johnson, Scrip Magazine, October, 1998, pp. 43-46); parvoviral vectors, such as adeno-associated viral (AAV) vectors (U.S. Pat. Nos. 5,474,9351; 5,139,941; 5,622,856; 5,658,776; 5,773,289; 5,789,390; 5,834,441; 5,863,541; 5,851,521; 5,252,479; Gnatenko etal., J. Invest. Med., 45: 87-98, 1997); adenoviral (AV) vectors (U.S. Pat. Nos. 5,792,453; 5,824,544; 5,707,618; 5,693,509; 5,670,488; 5,585,362; Quantin et al., Proc. Natl. Acad. Sci. USA, 89: 2581-2584, 1992; Stratford Perricaudet et al., J. Clin. Invest., 90: 626-630, 1992; and Rosenfeld et al., Cell, 68: 143-155, 1992); an adenoviral adeno-associated viral chimeric (U.S. Pat. No. 5,856,152) or a vaccinia viral or a herpesviral vector (U.S. Pat. Nos. 5,879,934; 5,849,571; 5,830,727; 5,661,033; 5,328,688); Lipofectin mediated gene transfer (BRL); liposomal vectors (U.S. Pat. No. 5,631,237); and combinations thereof. Any of these expression vectors can be prepared using standard recombinant DNA techniques described in, e.g., Sambrook et al. , Molecular Cloning, a Laboratory Manual, 2d edition, Cold Spring Harbor Press, Cold Spring Harbor, N.Y. (1989), and Ausubel et al., Current Protocols in Molecular Biology, Greene Publishing Associates and John Wiley & Sons, New York, N.Y. (1994). Optionally, viral vectors are rendered replication-deficient by, e.g., deleting or disrupting select genes required for viral replication.

[0260] Other non-viral delivery mechanisms contemplated include calcium phosphate precipitation (Graham and Van Der Eb, Virology, 52: 456-467, 1973; Chen and Okayama, Mol. Cell Biol., 7: 2745-2752, 1987; Rippe et al, Mol. Cell Biol., 10: 689-695, 1990) DEAE- dextran (Gopal, Mol. Cell Biol., 5: 1188-1190, 1985), electroporation (Tur-Kaspa et al., Mol. Cell Biol., 6: 716-718, 1986; Potter et al., Proc. Nat. Acad. Sci. USA, 81 : 7161-7165, 1984), direct microinjection (Harland and Weintraub, J. Cell Biol., 101 : 1094-1099, 1985), DNA- loaded liposomes (Nicolau and Sene, Biochim. Biophys. Acta, 721 : 185-190, 1982; Fraley et al., Proc. Natl. Acad. Sci. USA, 76: 3348-3352, 1979; Feigner, Sci Am., 276(6): 102-6, 1997; Feigner, Hum Gene Ther., 7(15): 1791-3, 1996), cell sonication (Fechheimer et al., Proc. Natl. Acad. Sci. USA, 84: 8463-8467, 1987), gene bombardment using high velocity microprojectiles (Yang et al., Proc. Natl. Acad. Sci USA, 87: 9568-9572, 1990), and receptor- mediated transfection (Wu and Wu, J. Biol. Chem., 262: 4429-4432, 1987; Wu and Wu, Biochemistry, 27: 887-892, 1988; Wu and Wu, Adv. Drug Delivery Rev., 12: 159-167, 1993).

[0261] A vector (or the antibody or fragment thereof or a nucleic acid as discussed herein) may be entrapped in a liposome. See, e.g., Ghosh and Bachhawat, In: Liver diseases, targeted diagnosis and therapy using specific receptors and ligands, Wu G, Wu C ed., New York: Marcel Dekker, pp. 87-104 (1991); Radler et al., Science, 275(5301): 810-814, (1997). Also contemplated are various commercial approaches involving “lipofection” technology. In some embodiments, the liposome may be complexed with a hemagglutinating virus (HVJ). This has been shown to facilitate fusion with the cell membrane and promote cell entry of liposome-encapsulated DNA (Kaneda et al., Science, 243: 375-378, 1989). In some embodiments, the liposome is complexed or employed in conjunction with nuclear nonhistone chromosomal proteins (HMG-1) (Kato et al., J. Biol. Chem., 266: 3361-3364, 1991). In some embodiments, the liposome is complexed or employed in conjunction with both HVJ and HMG-1. Such expression constructs have been successfully employed in transfer and expression of nucleic acid in vitro and in vivo. In some embodiments, an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, is included in the liposome to target the liposome to cells (such as a cancer cell) expressing IL13Ra2 on their surface.

[0262] A cell may comprise one or more polynucleotides or one or more vectors, e.g., the cell is transformed or transfected with one or more polynucleotides encoding an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, or the one or more vectors comprising the one or more polynucleotides. In some embodiments, cells express an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, containing one or more, including six CDRs having at least 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% identity to the CDRs of A22, A33, and / or A52 (see, e.g, Tables 1, 2, and / or 3). In some embodiments, the cell expresses an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, containing the VH and the VL comprising CDRs identical to those of A22, A33, and / or A52 (see, e.g., Tables 1, 2, and / or 3). The cells may be prokaryotic cells, such as Escherichia coli (see, e.g., Pluckthun et al., Methods Enzymol., 178: 497-515, 1989), or eukaryotic cells, such as an animal cell (e.g., a myeloma cell, Chinese Hamster Ovary (CHO) cell, or hybridoma cell), yeast (e.g., Saccharomyces cerevisiae), an insect cell, or a plant cell (e.g., a tobacco, corn, soybean, or rice cell). Use of mammalian host cells may provide for translational modifications (e.g., glycosylation, truncation, lipidation, and phosphorylation) that may be desirable to confer optimal biological activity on recombinant expression products. Similarly, polypeptides (e.g., IL13Ra2 binding agents (e.g., antibodies), including human IL13Ra2 binding agents)may be glycosylated or non-glycosylated and / or have been covalently modified to include one or more water soluble polymer attachments such as polyethylene glycol, polyoxyethylene glycol, or polypropylene glycol.

[0263] Methods for introducing DNA or RNA into host cells are well known and include transformation, transfection, electroporation, nuclear injection, or fusion with carriers such as liposomes, micelles, ghost cells, and protoplasts. Such host cells are useful for amplifying polynucleotides and also for expressing polypeptides encoded by the polynucleotides. In this regard, a process for the production of an IL13Ra2 binding agent (e.g., an antibody) may comprise culturing a host cell and isolating the IL13Ra2 binding agent. Transferring a naked DNA expression construct into cells can be accomplished using particle bombardment, which depends on the ability to accelerate DNA coated microprojectiles to a high velocity allowing them to pierce cell membranes and enter cells without killing them (Klein et aL, Nature, 327: 70-73, 1987). Several devices for accelerating small particles have been developed. One such device relies on a high voltage discharge to generate an electrical current, which in turn provides the motive force (Yang et al., Proc. Natl. Acad. Set USA, 87: 9568-9572, 1990). The microprojectiles used have consisted of biologically inert substances such as tungsten or gold beads. A host cell may be isolated and / or purified. A host cell also may be a cell transformed in vivo to cause transient or permanent expression of the polypeptide in vivo. A host cell may also be an isolated cell transformed ex vivo and introduced post-transformation, e.g., to produce the polypeptide in vivo for therapeutic purposes. The definition of host cell explicitly excludes a transgenic human being.5.4. Methods of Making

[0264] Antibodies that bind IL13Ra2 may be obtained by any suitable method, such as (but not limited to) immunization with whole cells comprising IL13Ra2 and collection of antibodies, recombinant techniques, or screening libraries of antibodies or antibody fragments using IL13Ra2 extracellular domain epitopes. Monoclonal antibodies may be generated using a variety of known techniques (see, for example, Coligan et al. (eds.), Current Protocols in Immunology, 1 :2.5.12.6.7 (John Wiley & Sons 1991); Monoclonal Antibodies, Hybridomas: A New Dimension in Biological Analyses, Plenum Press, Kennett, McKearn, and Bechtol (eds.) (1980); Antibodies: A Laboratory Manual, Harlow and Lane (eds.), Cold Spring Harbor Laboratory Press (1988); and Picksley et al., “Production of monoclonal antibodies against proteins expressed in E. colip in DNA Cloning 2: Expression Systems, 2nd Edition, Glover et al. (eds.), page 93 (Oxford University Press 1995)). One exemplary technique for generating monoclonal antibodies comprises immunizing an animal with ahuman IL13Ra2 antigen and generating a hybridoma from spleen cells taken from the animal. A hybridoma may produce a monoclonal antibody or antibody fragment that binds IL13Ra2.

[0265] In a further embodiment, monoclonal antibodies or antibody fragments can be isolated from antibody phage libraries generated using the techniques described in, for example, Antibody Phage Display: Methods and Protocols, P.M. O’Brien and R. Aitken, eds, Humana Press, Totawa N.J., 2002. In principle, synthetic antibody clones are selected by screening phage libraries containing phage that display various fragments of antibody variable region (Fv) fused to phage coat protein. Such phage libraries are screened for against the desired antigen. Clones expressing Fv fragments capable of binding to the desired antigen are adsorbed to the antigen and thus separated from the non-binding clones in the library. The binding clones are then eluted from the antigen, and can be further enriched by additional cycles of antigen adsorption / elution.

[0266] Variable domains can be displayed functionally on phage, either as single-chain Fv (scFv) fragments, in which VH and VL are covalently linked through a short, flexible peptide, or as Fab fragments, in which they are each fused to a constant domain and interact non-covalently, as described, for example, in Winter et al., Ann. Rev. Immunol, 12: 433-455 (1994).

[0267] Repertoires of VH and VL genes can be separately cloned by polymerase chain reaction (PCR) and recombined randomly in phage libraries, which can then be searched for antigen-binding clones as described in Winter et al., supra. Libraries from immunized sources provide high-affinity antibodies to the immunogen without the requirement of constructing hybridomas. Alternatively, the naive repertoire can be cloned to provide a single source of human antibodies to a wide range of non-self and also self antigens without any immunization as described by Griffiths et al., EMBO J, 12: 725-734 (1993). Finally, naive libraries can also be made synthetically by cloning the unrearranged V-gene segments from stem cells, and using PCR primers containing random sequence to encode the highly variable CDR3 regions and to accomplish rearrangement in vitro as described, for example, by Hoogenboom and Winter, J. Mol. Biol., 227: 381-388 (1992).

[0268] Screening of the libraries can be accomplished by various techniques known in the art. For example, IL13Ra2 (e.g., an IL13Ra2 polypeptide, fragment or epitope) can be used to coat the wells of adsorption plates, expressed on host cells affixed to adsorption plates or used in cell sorting, or conjugated to biotin for capture with streptavidin-coated beads, or used in any other method for panning display libraries. The selection of antibodies with slowdissociation kinetics (e.g., good binding affinities) can be promoted by use of long washes and monovalent phage display as described in Bass etal., Proteins, 8: 309-314 (1990) and in WO 92 / 09690, and a low coating density of antigen as described in Marks et al., BiotechnoL, 10: 779-783 (1992).

[0269] IL13Ra2 binding agents (e.g., antibodies) can be obtained by designing a suitable antigen screening procedure to select for the phage clone of interest followed by construction of a full length IL13Ra2 binding agent (e.g., an antibody) clone using VH and / or VL sequences (e.g., the Fv sequences), or various CDR sequences from VH and VL sequences, from the phage clone of interest and suitable constant region (e.g., Fc) sequences described in Kabat et al., Sequences of Proteins of Immunological Interest, Fifth Edition, NIH Publication 91-3242, Bethesda MD (1991), vols. 1-3.

[0270] Likewise, human antibodies that bind IL13Ra2 may be generated by any of a number of techniques including, but not limited to, Epstein Barr Virus (EBV) transformation of human peripheral blood cells (e.g., containing B lymphocytes), in vitro immunization of human B cells, fusion of spleen cells from immunized transgenic mice carrying inserted human immunoglobulin genes, isolation from human immunoglobulin V region phage libraries, or other procedures as known in the art and based on the disclosure herein.Methods for obtaining human antibodies from transgenic animals are further described, for example, in Bruggemann et al., Curr. Opin. BiotechnoL, 8: 455 58, 1997; Jakobovits et al, Ann. N. Y. Acad. ScL, 764: 525 35, 1995; Green et al., Nature Genet., 7: 13-21, 1994;Lonberg et al., Nature, 368: 856-859, 1994; Taylor et al., Int. Immun. 6: 579-591, 1994; and U.S. Pat. No. 5,877,397.

[0271] For example, human antibodies that bind IL13Ra2 may be obtained from transgenic animals that have been engineered to produce specific human antibodies in response to antigenic challenge. For example, WO 98 / 24893 discloses transgenic animals having a human Ig locus, wherein the animals do not produce functional endogenous immunoglobulins due to the inactivation of endogenous heavy and light chain loci. Transgenic non-primate mammalian hosts capable of mounting an immune response to an immunogen, wherein the antibodies have primate constant and / or variable regions, and wherein the endogenous immunoglobulin encoding loci are substituted or inactivated, also have been described. WO 96 / 30498 discloses the use of the Cre / Lox system to modify the immunoglobulin locus in a mammal, such as to replace all or a portion of the constant or variable region to form a modified antibody molecule. WO 94 / 02602 discloses non-human mammalian hosts having inactivated endogenous Ig loci and functional human Ig loci. U.S. Pat. No. 5,939,598discloses methods of making transgenic mice in which the mice lack endogenous heavy chains and express an exogenous immunoglobulin locus comprising one or more xenogeneic constant regions. Using a transgenic animal, such as a transgenic animal described herein, an immune response can be produced to a selected antigenic molecule, and antibody producing cells can be removed from the animal and used to produce hybridomas that secrete human- derived monoclonal antibodies. Immunization protocols, adjuvants, and the like are known in the art, and are used in immunization of, for example, a transgenic mouse as described in WO 96 / 33735. The monoclonal antibodies can be tested for the ability to inhibit or neutralize the biological activity or physiological effect of the corresponding protein.

[0272] In some embodiments, an IL13Ra2 binding agent described herein comprises a nonantibody protein scaffold. Non-limiting examples of such a non-antibody protein scaffold include a fibronectin scaffold, an anticalin, an adnectin, an affibody, a DARPin, a fynomer, an affitin, an affilin, an avimer, a cysteine-rich knottin peptide, or an engineered Kunitz-type inhibitor. Methods for generating such non-antibody protein scaffolds are well known in the art, any one of which can be used to generate an IL13Ra2 binding agent comprising a nonantibody protein scaffold (see, e.g., Simeon and Chen, Protein Cell, 9(1):3- 14 (2018); Yang et al., Annu Rev Anal Chem (Palo Alto Calif). 10(l):293-320 (2017)).

[0273] A variety of methods for producing antibodies from polynucleotides are generally well-known. For example, basic molecular biology procedures are described by Maniatis et al. , Molecular Cloning, A Laboratory Manual, 2nd ed., Cold Spring Harbor Laboratory, New York, 1989 (see also Maniatis et al., 3rd ed., Cold Spring Harbor Laboratory, New York, 2001). Additionally, numerous publications describe techniques suitable for the preparation of antibodies by manipulation of DNA, creation of expression vectors, and transformation and culture of appropriate cells (see, e.g., Mountain and Adair, Chapter 1 in Biotechnology and Genetic Engineering Reviews, Tombs ed., Intercept, Andover, UK, 1992); and Current Protocols in Molecular Biology, Ausubel ed., Wiley Interscience, New York, 1999).

[0274] An IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, is produced using any suitable method, e.g., isolated from an immunized animal, recombinantly or synthetically generated, or genetically-engineered, including as described above. Antibody fragments derived from an antibody are obtained by, e.g., proteolytic hydrolysis of an antibody. For example, papain or pepsin digestion of whole antibodies yields a 5S fragment termed F(ab’)2 or two monovalent Fab fragments and an Fc fragment, respectively. F(ab)2 can be further cleaved using a thiol reducing agent to produce 3.5S Fab monovalent fragments. Methods of generating antibody fragments are further described in,for example, Edelman et aL, Methods in Enzymology, 1 : 422 Academic Press (1967); Nisonoff et al., Arch. Biochem. Biophys., 89: 230-244, 1960; Porter, Biochem. J., 73: 119- 127, 1959; U.S. Pat. No. 4,331,647; and by Andrews, S.M. and Titus, J. A. in Current Protocols in Immunology (Coligan et al., eds), John Wiley & Sons, New York (2003), pages 2.8.1 2.8.10 and 2.10A.1 2.10A.5.

[0275] An IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, can be genetically engineered. For example, an IL13Ra2 binding agent (e.g., an antibody), including a human IL13Ra2 binding agent, comprises, for example, a variable region domain generated by recombinant DNA engineering techniques. In this regard, a variable region is optionally modified by insertions, deletions, or changes in the amino acid sequence of the antibody to produce an antibody of interest, including as described above. Polynucleotides encoding CDRs of interest are prepared, for example, by using polymerase chain reaction to synthesize variable regions using mRNA of antibody producing cells as a template (see, for example, Courtenay Luck, “Genetic Manipulation of Monoclonal Antibodies,” in Monoclonal Antibodies: Production, Engineering and Clinical Application, Ritter et al. (eds.), page 166 (Cambridge University Press 1995); Ward et al, “Genetic Manipulation and Expression of Antibodies,” in Monoclonal Antibodies: Principles and Applications, Birch et al., (eds.), page 137 (Wiley Liss, Inc. 1995); and Larrick et al, Methods: A Companion to Methods in Enzymology, 2: 106-110, 1991). Current antibody manipulation techniques allow construction of engineered variable region domains containing at least one CDR and, optionally, one or more framework amino acids from a first antibody and the remainder of the variable region domain from a second antibody. Such techniques are used, e.g., to humanize an antibody or to improve its affinity for a binding target.Exemplary methods for generating humanized antibodies are described in sections above too.5.5. Pharmaceutical Compositions

[0276] In one aspect, the present disclosure further provides a composition, such as a pharmaceutical composition, comprising at least one of the following: a binding agent provided herein (e.g., one antibody or antigen-binding fragment thereof of the present disclosure), a nucleic acid provided herein, a vector provided herein, or a cell provided herein. In some embodiments, a pharmaceutical composition comprises a therapeutically effective amount of an IL13Ra2 binding agent provided herein (e.g., an antibody or antigenbinding fragment thereof provided herein) and a pharmaceutically acceptable excipient. In some embodiments, a pharmaceutical composition comprises a therapeutically effective amount of a nucleic acid provided herein (such as a nucleic acid encoding an antibody orantigen-binding fragment thereof provided herein) and a pharmaceutically acceptable excipient. In some embodiments, a pharmaceutical composition comprises a therapeutically effective amount of a vector provided herein (such as a vector comprising a nucleic acid as disclosed herein and expressing an IL13Ra2 binding agent as disclosed herein) and a pharmaceutically acceptable excipient. In some embodiments, a pharmaceutical composition comprises a therapeutically effective amount of a cell provided herein (such as a cell comprising a nucleic acid encoding an antibody or antigen-binding fragment thereof provided herein and / or expressing an antibody or antigen-binding fragment thereof provided herein) and a pharmaceutically acceptable excipient.

[0277] In some embodiments, pharmaceutical compositions provided herein are prepared for storage by mixing the binding agents, nucleic acids, vectors, or cells provided herein having the desired degree of purity with optional physiologically acceptable excipients (see, e.g., Remington, Remington’s Pharmaceutical Sciences (18th ed. 1980)) in the form of aqueous solutions or lyophilized or other dried forms.

[0278] The binding agents, nucleic acids, vectors, or cells of the present disclosure may be formulated in any suitable form for delivery to a target cell / tissue, e.g., as microcapsules or macroemulsions (Remington, supra, Park et al., 2005, Molecules 10: 146-61; Malik et al., 2007, Curr. Drug. Deliv. 4: 141-51), as sustained release formulations (Putney and Burke, 1998, Nature Biotechnol. 16: 153-57), or in liposomes (Maclean et al., 1997, Int. J. Oncol. 11 :325-32; Kontermann, 2006, Curr. Opin. Mol. Ther. 8:39-45).

[0279] The binding agents, nucleic acids, vectors, or cells provided herein can also be entrapped in microcapsule prepared, for example, by coacervation techniques or by interfacial polymerization, for example, hydroxymethylcellulose or gelatin-microcapsule and poly-(methylmethacylate) microcapsule, respectively, in colloidal drug delivery systems (for example, liposomes, albumin microspheres, microemulsions, nano-particles, and nanocapsules) or in macroemulsions. Such techniques are disclosed, for example, in Remington, supra.

[0280] Various compositions and delivery systems are known and can be used with the binding agents, nucleic acids, vectors or cells as described herein, including, but not limited to, encapsulation in liposomes, microparticles, microcapsules, recombinant cells capable of expressing the antibody or antigen-binding fragment thereof, receptor-mediated endocytosis (see, e.g., Wu and Wu, 1987, J. Biol. Chem. 262:4429-32), construction of a nucleic acid as part of a retroviral or other vector, etc. In another embodiment, a composition can be provided as a controlled release or sustained release system. In one embodiment, a pumpmay be used to achieve controlled or sustained release (see, e.g., Langer, supra, Sefton, 1987, Crit. Ref. Biomed. Eng. 14:201-40; Buchwald et al., 1980, Surgery 88:507-16; and Saudek et al., 1989, N. Engl. J. Med. 321 :569-74). In another embodiment, polymeric materials can be used to achieve controlled or sustained release of a prophylactic or therapeutic agent (e.g., an antibody or antigen-binding fragment thereof as described herein) or a composition provided herein (see, e.g., Medical Applications of Controlled Release (Langer and Wise eds., 1974); Controlled Drug Bioavailability, Drug Product Design and Performance (Smolen and Ball eds., 1984); Ranger and Peppas, 1983, J. Macromol. Sci. Rev. Macromol. Chem. 23:61-126; Levy et al., 1985, Science 228: 190-92; During et al., 1989, Ann. Neurol. 25:351-56; Howard et al., 1989, J. Neurosurg. 71 : 105-12; U.S. Pat. Nos. 5,679,377; 5,916,597; 5,912,015; 5,989,463; and 5,128,326; WO 99 / 15154 and WO 99 / 20253). Examples of polymers used in sustained release formulations include, but are not limited to, poly(2-hydroxy ethyl methacrylate), poly(methyl methacrylate), poly(acrylic acid), poly(ethylene-co-vinyl acetate), poly(methacrylic acid), polyglycolides (PLG), polyanhydrides, poly(N-vinyl pyrrolidone), poly(vinyl alcohol), polyacrylamide, polyethylene glycol), polylactides (PLA), poly(lactide- co-glycolides) (PLGA), and poly orthoesters. In one embodiment, the polymer used in a sustained release formulation is inert, free of leachable impurities, stable on storage, sterile, and biodegradable.

[0281] In yet another embodiment, a controlled or sustained release system can be placed in proximity of a particular target tissue, for example, the nasal passages or lungs, thus requiring only a fraction of the systemic dose (see, e.g., Goodson, Medical Applications of Controlled Release Vol. 2, 115-38 (1984)). Controlled release systems are discussed, for example, by Langer, 1990, Science 249: 1527-33. Any technique known to one of skill in the art can be used to produce sustained release formulations comprising one or more antibody or antigen-binding fragment thereof as described herein (see, e.g., U.S. Pat. No. 4,526,938, WO 91 / 05548 and WO 96 / 20698, Ning et al., 1996, Radiotherapy & Oncology 39: 179-89; Song et al., 1995, PDA J. of Pharma. Sci. & Tech. 50:372-97; Cleek et al., 1997, Pro. IntT. Symp. Control. Rel. Bioact. Mater. 24:853-54; and Lam et al., 1997, Proc. IntT. Symp. Control Rel. Bioact. Mater. 24:759-60).5.6. Methods of Uses

[0282] In another aspect, provided herein are methods for using the binding agent or the composition provided herein. In a further aspect, provided herein are binding agents or compositions as disclosed herein for use as a medicament. In yet a further aspect, provided herein are binding agents or compositions as disclosed herein for use in the treatment of adisease or condition, such as those disclosed herein. In one aspect, provided herein are binding agents or compositions as disclosed herein for use in a method as disclosed herein.

[0283] In some embodiments, the binding agents bind to IL13Ra2. In some embodiments, the binding agents bind to an IL13Ra2 epitope. Additionally or alternatively, the binding agents bind to a complex comprising IL13Ra2 and IL 13. In further embodiments, the binding agents bind to a complex comprising the extracellular domains of IL13Ra2 and IL13. In yet further embodiments, the binding agents bind to an epitope of a complex comprising the ECD of IL13Ra2 and IL13. In various embodiments, the IL13Ra2 is a human IL13Ra2. In further embodiments, the IL13Ra2 also refers to a cyno IL13Ra2. In other embodiments, the binding agents do not bind to cyno IL13Ra2 or a complex comprising a cyno IL13Ra2. In other embodiments, the binding agents do not bind to IL13Ral.

[0284] In some embodiments, provided herein is a method of identifying a cell expressing IL13Ra2 (include a cell overexpressing IL13Ra2). In some embodiments, provided herein is a method for reducing (including but not limited to abolishing) viability or proliferation of an IL13Ra2-expressing cell (include an IL13Ra2-overexpressing cell). In some embodiments, , provided herein is a method of killing an IL13Ra2-expressing cell (include an IL13Ra2- overexpressing cell). In further embodiments, the IL13Ra2-expressing cell is a cancer cell. Exemplary cancer cell type include but not limited to: melanoma cell, lung cancer (including non-small cell lung cancer) cell, colorectal cancer cell, malignant gliomas cell, pancreatic cancer cell, ovarian cancer cell, breast cancer cell, liver cancer cell, head and neck cancer cell, and renal cancer cell.

[0285] In some embodiments, a method as disclosed herein is an in vitro method or an ex vivo method. In other embodiments, a method as disclosed herein is an in vivo method. In some embodiments, a use as disclosed herein is an in vitro use or an ex vivo use. In other embodiments, a use as disclosed herein is an in vivo use. In some embodiments, an in vivo method or an in vivo use as disclosed herein comprises administering a binding agent as disclosed herein to a subject having a cell expressing IL13Ra2, such as a tumor cell expressing IL13Ra2.Therapeutic Uses and Methods of Treatment

[0286] In some embodiments, IL13Ra2 binding agents (e.g., antibodies) described herein are useful in compositions and in methods of treating a disease or disorder. Thus, in some embodiments, provided herein is a method for treating a disease or disorder in a subject comprising administering the binding agent or the pharmaceutical composition provided herein to the subject. In other embodiments, provided herein is a use of the binding agent orpharmaceutical composition provided herein for treating a disease or disorder in a subject. In other embodiments, provided herein is a binding agent or pharmaceutical composition provided herein for use in the manufacture of a medicament for the treatment of a disease or disorder.

[0287] In some embodiments, the treatment provided herein includes alleviating one or more symptoms associated with a disease or disorder (e.g., a cancer or a tumor).

[0288] Thus, in some embodiments, provided herein is a method for alleviating one or more symptoms associated with a cancer or a tumor in a subject comprising administering to the subject an IL13Ra2 binding agent (e.g., an antibody) described herein or a pharmaceutical composition described herein. In some embodiments, provided herein is an IL13Ra2 binding agent (e.g., an antibody) described herein or a pharmaceutical composition described herein for use in alleviating one or more symptoms associated with a cancer or a tumor in a subject. In some embodiments, provided herein is use of an IL13Ra2 binding agent (e.g., an antibody) described herein or a pharmaceutical composition described herein in the manufacture of a medicament for alleviating one or more symptoms associated with a cancer or a tumor in a subject.

[0289] In some embodiments, the treatment provided herein includes decreasing tumor size in a subject with a tumor. Thus, in some embodiments, described herein is a method for decreasing tumor size in a subject with a tumor comprising administering to the subject an IL13Ra2 binding agent (e.g., an antibody) described herein or a pharmaceutical composition described herein. In some embodiments, provided herein is an IL13Ra2 binding agent (e.g., an antibody) described herein or a pharmaceutical composition described herein for use in decreasing tumor size in a subject with a tumor. In some embodiments, provided herein is use of an IL13Ra2 binding agent (e.g., an antibody) described herein or a pharmaceutical composition described herein in the manufacture of a medicament for decreasing tumor size in a subject with a tumor.

[0290] In some embodiments, described herein is a method for enhancing tumor cell removal in a subject with a tumor comprising administering to the subject IL13Ra2 binding agent (e.g, an antibody) described herein or a pharmaceutical composition described herein. In some embodiments, provided herein is an IL13Ra2 binding agent (e.g, an antibody) described herein or a pharmaceutical composition described herein for use in enhancing tumor cell removal in a subject with a tumor. In some embodiments, provided herein is use of an IL13Ra2 binding agent (e.g., an antibody) described herein or a pharmaceuticalcomposition described herein in the manufacture of a medicament for enhancing tumor cell removal in a subject with a tumor.

[0291] “Enhancing” tumor cell removal includes, yet does not require a 100% enhancement of removal. Any enhancement in the rate of removal is contemplated. Similarly, “modulating” tumor growth refers to reducing the size of the tumor, slowing tumor growth, or inhibiting an increase in the size of an existing tumor. Complete abolition of a tumor is included but not required; any decrease in tumor size or slowing of tumor growth constitutes a beneficial biological effect in a subject. In this regard, tumor cell removal may be enhanced by, for example, at least about 5%, at least about 10% or at least about 20% compared to levels of removal observed in the absence of the method (e.g., in a biologically-matched control subject or specimen that is not exposed to the agent of the method). The effect is detected by, for example, a reduction in tumor size, a decrease or maintenance of the levels of tumor markers, or reduction or maintenance of a tumor cell population. In some embodiments, removal of tumor cells is enhanced by, for example, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or more (about 100%) compared to the removal of tumor cells in the absence of an IL13Ra2 binding agent (e.g., an antibody) or a pharmaceutical composition of the method.

[0292] A method of modulating (e.g. , inhibiting, reducing, preventing) tumor growth in a subject also is provided. For example, the method comprises administering to the subject a composition comprising an IL13Ra2 binding agent (e.g., an antibody) or another composition as disclosed herein in an amount effective to modulate tumor growth in the subject.

[0293] In some embodiments, the disease or disorder is a cancer or a tumor. In further embodiments, the cancer or tumor expresses IL13Ra2. In further embodiments, the cancer or tumor overexpresses IL13Ra2. In some embodiments, the subject is a human subject.

[0294] As used herein, “tumor” refers to any neoplastic cell growth or proliferation, whether malignant or benign, and to all pre-cancerous and cancerous cells and tissues. The terms “cancer” and “cancerous” refer to or describe the physiological condition in mammals that is typically characterized by unregulated cell growth. Examples of cancers include, but are not limited to: melanoma, lung cancer (including non-small cell lung cancer), colorectal cancer (CRC), malignant gliomas, pancreatic cancer, ovarian cancer, breast cancer, liver cancer, head and neck cancer, and renal cancer.

[0295] In some embodiments, the tumor is a solid tumor. In some embodiments, the tumor or cancer is not a solid tumor. In further embodiments, the cancer is a leukemia cancer. Insome embodiments, the tumor or cancer is a relapsed tumor or cancer. In some embodiments, the tumor or cancer is a metastatic tumor or cancer. In some embodiments, the tumor ro cancer is a primary tumor or cancer. In some embodiments, the tumor or cancer reaches a remission, but can relapse. In some embodiments, the tumor or cancer is unresectable. Additionally or alternatively, the tumor or cancer is resistant to a chemotherapy or other anticancer therapy. In further embodiments, the cancer or tumor expresses IL13Ra2. In further embodiments, the cancer or tumor overexpresses IL13Ra2.

[0296] Additionally, IL13Ra2 binding agents (e.g., antibodies) may be used to alleviate or reduce side effects associated with cancer such as, for example, bone deterioration, vertebral collapse, and paralysis. In one aspect, the subject suffers from or is at risk of suffering from bone metastases and an IL13Ra2 binding agent (e.g., an antibody) is administered in an amount to reduce deterioration of surrounding bone. Accordingly, in some aspects, an IL13Ra2 binding agent prevents bone deterioration due to bone metastases, wherein tumor cell proliferation is or is not reduced. In some aspects, an IL13Ra2 binding agent (e.g., an antibody) both prevents bone deterioration due to bone metastases and reduces tumor cell proliferation. In general, the effect on tumor cell proliferation (e.g., inhibition of proliferation or no effect on proliferation) depends on the microenvironment of a particular metastasis. For example, proliferation of metastases located in microenvironments with substantial amounts of type 1 collagen may be inhibited. In contrast, proliferation of metastases located in microenvironments lacking substantial amounts of type 1 collagen may not be inhibited, yet bone deterioration in the vicinity of the metastasis is reduced or prevented.

[0297] Also provided is a method of treating a disease or disorder (e.g., a cancer) by administering an IL13Ra2 binding agent (e.g., an antibody) such as a human IL13Ra2 binding agent, or a pharmaceutical composition as disclosed herein, to a subject in need thereof, alone or in combination with another agent.

[0298] The subject of a method described herein can be administered one or more additional therapeutic agents in combination with an IL13Ra2 binding agent (e.g, an antibody) described herein or fragment thereof or a pharmaceutical composition described herein. An additional agent can be an agent that targets a tumor or a cancer cell. An additional agent can also be an agent that targets an immune cell (e.g, an NK cell or a T cell). In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by about 10% - 90% or about 2- 100 folds. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 10%. Insome embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 20%. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 30%. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 40%. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 50%. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 60%. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 70%. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 80%. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 90%. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 2 fold. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 5 fold. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 10 fold. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by at least 20 fold. In some embodiments, the IL13Ra2 binding agent or pharmaceutical composition provided herein increases a therapeutic effect of the additional agent by more than 50 fold.

[0299] A particular administration regimen of an IL13Ra2 binding agent (e.g., an antibody) or pharmaceutical composition as disclosed herein for a particular subject will depend, in part, upon the agent used, the amount of agent administered, the route of administration, and the cause and extent of any side effects. The amount of agent (e.g., an antibody) administered to a subject (e.g., a mammal, such as a human) should be sufficient to effect the desired response over a reasonable time frame. According, in some embodiments, the amount of an IL13Ra2 binding agent (e.g., an antibody) or pharmaceutical composition described herein administered to a subject is an effective amount.

[0300] Suitable routes of administering an IL13Ra2 binding agent (e.g., an antibody), such as a human IL13Ra2 binding agent (e.g., an antibody) or a compositions described herein, are well known in the art, such as intravenous injection (such as intravenous infusion), intratumoral injection, or injection adjacent to a tumor or cancer. Although more than one route can be used to administer an agent e.g., an antibody), a particular route can provide a more immediate and more effective reaction than another route.Gene and Cellular Therapies

[0301] In some embodiments, the composition for use according to the present disclosure comprises one or more nucleic acids encoding an IL13Ra2 binding agent provided herein (e.g., an antibody or fragment thereof) or complementary nucleic acids thereto. In a specific embodiment, the nucleic acids are administered to a subject for use in a method provided herein, for example, to prevent, manage, treat and / or ameliorate a disease or disorder (e.g., a cancer, for example a cancer expressing IL13Ra2) by way of gene therapy. Such therapy encompasses that performed by the administration to a subject of an expressed or expressible nucleic acid. In an embodiment, the nucleic acids produce their encoded antibody, and the antibody mediates a prophylactic or therapeutic effect.

[0302] Any of the methods for recombinant gene expression (or gene therapy) available in the art can be used.

[0303] For general review of the methods of gene therapy, see Goldspiel et al., 1993, Clinical Pharmacy 12:488-505; Wu and Wu, 1991, Biotherapy 3:87-95; Tolstoshev, 1993, Ann. Rev. Pharmacol. Toxicol. 32:573-596; Mulligan, 1993, Science 260:926-932; and Morgan and Anderson, 1993, Ann. Rev. Biochem. 62: 191-217; May, 1993, TIBTECH 11(5): 155-215. Methods commonly known in the art of recombinant DNA technology which can be used are described in Ausubel et al. (eds.), Current Protocols in Molecular Biology, John Wiley & Sons, NY (1993); and Kriegler, Gene Transfer and Expression, A Laboratory Manual, Stockton Press, NY (1990).

[0304] In a specific embodiment, a composition comprises nucleic acids encoding an antibody or a fusion protein provided herein, the nucleic acids being part of an expression vector that expresses the antibody or fusion proteins or heavy or light chains thereof in a suitable host. In particular, such nucleic acids have promoters, such as heterologous promoters, operably linked to the coding region, the promoter being inducible or constitutive, and, optionally, tissue-specific and / or tumor / cancer-specific. In another particular embodiment, nucleic acid molecules are used in which the antibody sequences and any other desired sequences are flanked by regions that promote homologous recombination at adesired site in the genome, thus providing for intrachromosomal expression of the antibody or fusion protein encoding nucleic acids (Koller and Smithies, 1989, Proc. Natl. Acad. Sci. USA 86:8932-8935; Zijlstra et al., 1989, Nature 342:435-438).

[0305] Delivery of the nucleic acids into a subject can be either direct, in which case the subject is directly exposed to the nucleic acid or nucleic acid-carrying vectors, or indirect, in which case, cells are first transformed with the nucleic acids in vitro, then transplanted into the subject. These two approaches are known, respectively, as in vivo or ex vivo gene therapy.

[0306] In a specific embodiment, the nucleic acid sequences are directly administered in vivo, where the sequences are expressed to produce the encoded product. This can be accomplished by any of numerous methods known in the art, e.g., by constructing them as part of an appropriate nucleic acid expression vector and administering the vector so that the sequences become intracellular, e.g., by infection using defective or attenuated retroviral or other viral vectors (see U.S. Pat. No. 4,980,286), or by direct injection of naked DNA, or by use of microparticle bombardment (e.g., a gene gun; Biolistic, Dupont), or coating with lipids or cell surface receptors or transfecting agents, encapsulation in liposomes, microparticles, or microcapsules, or by administering them in linkage to a peptide which is known to enter the nucleus, by administering it in linkage to a ligand subject to receptor-mediated endocytosis (see, e.g., Wu and Wu, 1987, J. Biol. Chem. 262:4429-4432) (which can be used to target cell types specifically expressing the receptors), etc. In another embodiment, nucleic acid-ligand complexes can be formed in which the ligand comprises a fusogenic viral peptide to disrupt endosomes, allowing the nucleic acid to avoid lysosomal degradation. In yet another embodiment, the nucleic acid can be targeted in vivo for cell specific uptake and expression, by targeting a specific receptor (see, e.g., WO 92 / 06180; WO 92 / 22635; WO 92 / 20316; WO 93 / 14188, WO 93 / 20221). Alternatively, the nucleic acid can be introduced intracellularly and incorporated within host cell DNA for expression, by homologous recombination (Koller and Smithies, 1989, Proc. Natl. Acad. Sci. USA 86:8932-8935; and Zijlstra et al., 1989, Nature 342:435-438).

[0307] In a specific embodiment, viral vectors that contains nucleic acid sequences encoding an antibody are used. For example, a retroviral vector can be used (see Miller et al., 1993, Meth. Enzymol. 217:581-599). These retroviral vectors contain the components necessary for the correct packaging of the viral genome and integration into the host cell DNA. The nucleic acid sequences encoding the antibody to be used in gene therapy can be cloned into one or more vectors, which facilitates delivery of the gene into a subject. More detail about retroviral vectors can be found in Boesen et al., 1994, Biotherapy 6:291-302,which describes the use of a retroviral vector to deliver the MDR1 gene to hematopoietic stem cells in order to make the stem cells more resistant to chemotherapy. Other references illustrating the use of retroviral vectors in gene therapy are: Clowes et al., 1994, J. Clin. Invest. 93:644-651; Klein et al., 1994, Blood 83: 1467-1473; Salmons and Gunzberg, 1993, Human Gene Therapy 4: 129-141; and Grossman and Wilson, 1993, Curr. Opin. in Genetics and Devel. 3: 110-114.

[0308] Adenoviruses are other viral vectors that can be used in the recombinant production of antibodies. Adenoviruses are especially attractive vehicles for delivering genes to respiratory epithelia. Adenoviruses naturally infect respiratory epithelia where they cause a mild disease. Other targets for adenovirus-based delivery systems are liver, the central nervous system, endothelial cells, and muscle. Adenoviruses have the advantage of being capable of infecting non-dividing cells. Kozarsky and Wilson, 1993, Current Opinion in Genetics and Development 3:499-503 present a review of adenovirus-based gene therapy. Bout et al., 1994, Human Gene Therapy 5:3-10 demonstrated the use of adenovirus vectors to transfer genes to the respiratory epithelia of rhesus monkeys. Other instances of the use of adenoviruses in gene therapy can be found in Rosenfeld et al., 1991, Science 252:431-434; Rosenfeld et al., 1992, Cell 68: 143-155; Mastrangeli et al., 1993, J. Clin. Invest. 91 :225-234; PCT Publication W094 / 12649; and Wang et al., 1995, Gene Therapy 2:775-783. In a specific embodiment, adenovirus vectors are used.

[0309] Adeno-associated virus (AAV) can also be utilized (Walsh et al., 1993, Proc. Soc. Exp. Biol. Med. 204:289-300; and U.S. Pat. No. 5,436,146). In a specific embodiment, AAV vectors are used to express an anti-IL13Ra2 antibody as provided herein. In certain embodiments, the AAV comprises a nucleic acid encoding a VH domain. In other embodiments, the AAV comprises a nucleic acid encoding a VL domain. In certain embodiments, the AAV comprises a nucleic acid encoding a VH domain and a VL domain.In some embodiments of the methods provided herein, a subject is administered an AAV comprising a nucleic acid encoding a VH domain and an AAV comprising a nucleic acid encoding a VL domain. In other embodiments, a subject is administered an AAV comprising a nucleic acid encoding a VH domain and a VL domain. In certain embodiments, the VH and VL domains are over-expressed.

[0310] In some embodiments, oncolytic viruses may be used in the recombinant production of antibodies provided herein. An oncolytic virus may preferentially infect and kill cancer cells. As the infected cancer cells are destroyed by oncolysis, they may release new infectious virus particles or virions to help destroy the remaining tumor. In a specific embodiment, anoncolytic virus is a virus that when injected into a tumor results in tumor regression. In another specific embodiment, an oncolytic virus is a virus that selectively replicates in and kills cancer cells, and spreads within the tumor. In another specific embodiment, an oncolytic virus is a virus that selectively replicates in and kills cancer cells, and spreads within the tumor without causing any significant damage to normal tissue. In some embodiments, an in vitro or ex vivo assay known to one skilled in the art is used to determine the selectively of a virus to replicate in cancer cells versus non-cancerous cells (e.g., healthy cells). In one embodiment, a virus selectively replicates in cancer cells if a statistically significant increase in the number of virus particles is detected in cancer cells in an in vitro assay or ex vivo assay relative to the number of virus particles detected in non-cancerous cells (e.g., healthy cells) in the same assay after incubation with the virus. In another embodiment, a virus selectively kills cancer cells if a statistically significant amount of the cancer cells are killed in an in vitro or ex vivo assay relative to the amount of non-cancerous cells (e.g., healthy cells) killed in the same assay. In one embodiment, an oncolytic virus naturally preferentially replicates in cancer cells and is non-pathogenic in humans. An oncolytic virus may be non-pathogenic in humans due to elevated sensitivity to innate antiviral signal or dependence on oncogenic signaling pathways. In some embodiments, an oncolytic virus is a parovirus (e.g., an autonomous parvovirus), a myxoma virus, an avian paramyxovirus (e.g., Newcastle disease virus), a reovirus, or Seneca valley virus. In one embodiment, an oncolytic virus is wild-type parvovirus Hl (ParvOryx). In another embodiment, an oncolytic virus is Vesicular stomatitis virus. In another embodiment, an oncolytic virus is an avian paramyxovirus. In some embodiments, an oncolytic virus is a genetically engineered influenza virus, measles virus, poliovirus, vaccinia virus, poxvirus, picornavirus, alphavirus, retrovirus, rhabdovirus, reovirus, adenovirus, herpes simplex virus, or vesicular stomatitis virus. In some embodiments, such viruses are attenuated.

[0311] Another approach to gene and cell therapy involves transferring a gene to cells in tissue culture by such methods as electroporation, lipofection, calcium phosphate mediated transfection, or viral infection. Usually, the method of transfer includes the transfer of a selectable marker to the cells. The cells are then placed under selection to isolate those cells that have taken up and are expressing the transferred gene. Those cells are then delivered to a subject.

[0312] In this embodiment, the nucleic acid is introduced into a cell prior to administration in vivo of the resulting recombinant cell. Such introduction can be carried out by any method known in the art, including but not limited to transfection, electroporation, microinjection,infection with a viral or bacteriophage vector containing the nucleic acid sequences, cell fusion, chromosome-mediated gene transfer, microcellmediated gene transfer, spheroplast fusion, etc. Numerous techniques are known in the art for the introduction of foreign genes into cells (see, e.g., Loeffler and Behr, 1993, Meth. Enzymol. 217:599-618; Cohen etal., 1993, Meth. Enzymol. 217:618-644; Clin. Pharma. Ther. 29:69-92 (1985)) and can be used in accordance with the methods provided herein, provided that the necessary developmental and physiological functions of the recipient cells are not disrupted. The technique should provide for the stable transfer of the nucleic acid to the cell, so that the nucleic acid is expressible by the cell, such as heritable and expressible by its cell progeny.

[0313] The resulting recombinant cells can be delivered to a subject by various methods known in the art. Recombinant blood cells (e.g, hematopoietic stem or progenitor cells) can be administered intravenously. The amount of cells envisioned for use depends on the desired effect, patient state, etc., and can be determined by one skilled in the art.

[0314] Cells into which a nucleic acid can be introduced for purposes of gene and / or cell therapy encompass any desired, available cell type, and include but are not limited to epithelial cells, endothelial cells, keratinocytes, fibroblasts, muscle cells, hepatocytes; blood cells such as T lymphocytes, B lymphocytes, monocytes, macrophages, neutrophils, eosinophils, megakaryocytes, granulocytes; various stem or progenitor cells, in particular hematopoietic stem or progenitor cells, e.g, as obtained from bone marrow, umbilical cord blood, peripheral blood, fetal liver, etc.

[0315] In a specific embodiment, the cell used for gene and / or cell therapy is autologous to the subject. In other embodiments, the cell used for cell and / or gene therapy is allogeneic to the subject.

[0316] In an embodiment in which recombinant cells are used in gene and / or cell therapy, nucleic acid sequences encoding an antibody are introduced into the cells such that they are expressible by the cells or their progeny, and the recombinant cells are then administered in vivo for therapeutic effect. In a specific embodiment, stem or progenitor cells are used. Any stem and / or progenitor cells which can be isolated and maintained in vitro can potentially be used in accordance with this embodiment of the methods provided herein (see e.g., WO 94 / 08598; Stemple and Anderson, 1992, Cell 7 1 :973-985; Rheinwald, 1980, Meth. Cell Bio. 21A:229; and Pittelkow and Scott, 1986, Mayo Clinic Proc. 61 :771).

[0317] In a specific embodiment, the nucleic acid to be introduced for purposes of gene and / or cell therapy comprises an inducible promoter operably linked to the coding region,such that expression of the nucleic acid is controllable by controlling the presence or absence of the appropriate inducer of transcription.Diagnostic Uses and Methods of Detection

[0318] Labeled binding molecules such as labeled antibodies and derivatives and analogs thereof, which immunospecifically bind to an antigen can be used for diagnostic purposes to detect, diagnose, or monitor a disease.

[0319] Antibodies provided herein can be used to assay an antigen level in a biological sample using classical immunohistological methods as described herein or as known to those of skill in the art (e.g., see Jalkanen etal., 1985, J. Cell. Biol. 101 :976-985; and Jalkanen et al., 1987, J. Cell. Biol. 105:3087-3096). Other antibody-based methods useful for detecting protein gene expression include immunoassays, such as the enzyme linked immunosorbent assay (ELISA) and the radioimmunoassay (RIA). Suitable antibody assay labels are known in the art and include enzyme labels, such as, glucose oxidase; radioisotopes, such as iodine (125I,121I), carbon (14C), sulfur (35S), tritium (3H), indium (121In), and technetium ("Tc); luminescent labels, such as luminol; and fluorescent labels, such as fluorescein and rhodamine, and biotin.

[0320] It will be understood in the art that the size of the subject and the imaging system used will determine the quantity of imaging moiety needed to produce diagnostic images. In the case of a radioisotope moiety, for a human subject, the quantity of radioactivity injected will normally range from about 5 to 20 millicuries of "Tc. The labeled antibody will then accumulate at the location of cells which contain the specific protein. In vivo tumor imaging is described in S.W. Burchiel et al, “Immunopharmacokinetics of Radiolabeled Antibodies and Their Fragments.” (Chapter 13 in Tumor Imaging: The Radiochemical Detection of Cancer, S.W. Burchiel and B.A. Rhodes, eds., Masson Publishing Inc. (1982)).

[0321] Depending on several variables, including the type of label used and the mode of administration, the time interval following the administration for permitting the labeled antibody to concentrate at sites in the subject and for unbound labeled antibody to be cleared to background level is 6 to 48 hours or 6 to 24 hours or 6 to 12 hours. In another embodiment the time interval following administration is 5 to 20 days or 5 to 10 days.

[0322] Presence of the labeled molecule can be detected in the subject using methods known in the art for in vivo scanning. These methods depend upon the type of label used. Skilled artisans will be able to determine the appropriate method for detecting a particular label. Methods and devices that may be used in the diagnostic methods provided hereininclude, but are not limited to, computed tomography (CT), whole body scan such as position emission tomography (PET), magnetic resonance imaging (MRI), and sonography.

[0323] In a specific embodiment, the molecule is labeled with a radioisotope and is detected in the patient using a radiation responsive surgical instrument (Thurston et cd., U.S. Pat. No. 5,441,050). In another embodiment, the molecule is labeled with a fluorescent compound and is detected in the patient using a fluorescence responsive scanning instrument. In another embodiment, the molecule is labeled with a positron emitting metal and is detected in the patient using positron emission-tomography. In yet another embodiment, the molecule is labeled with a paramagnetic label and is detected in a patient using magnetic resonance imaging (MRI).5.7. Kits

[0324] Also provided herein are kits comprising an IL13Ra2 binding agent (e.g., an anti- IL13Ra2 antibody) provided herein, or a composition (e.g., a pharmaceutical composition) provided herein, packaged into suitable packaging material. A kit optionally includes a label or packaging insert including a description of the components or instructions for use in vitro, in vivo, or ex vivo, of the components therein.

[0325] The term “packaging material” refers to a physical structure housing the components of the kit. The packaging material can maintain the components sterilely, and can be made of material commonly used for such purposes (e.g., paper, corrugated fiber, glass, plastic, foil, ampoules, vials, tubes, etc.).

[0326] Kits provided herein can include labels or inserts. Labels or inserts include “printed matter,” e.g., paper or cardboard, separate or affixed to a component, a kit or packing material (e.g, a box), or attached to, for example, an ampoule, tube, or vial containing a kit component. Labels or inserts can additionally include a computer readable medium, such as a disk (e.g, hard disk, card, memory disk), optical disk such as CD- or DVD-ROM / RAM, DVD, MP3, magnetic tape, or an electrical storage media such as RAM and ROM or hybrids of these such as magnetic / optical storage media, FLASH media, or memory type cards. Labels or inserts can include information identifying manufacturer information, lot numbers, manufacturer location, and date.

[0327] Kits provided herein can additionally include other components. Each component of the kit can be enclosed within an individual container, and all of the various containers can be within a single package. Kits can also be designed for cold storage. A kit can further be designed to contain antibodies provided herein, or cells that contain nucleic acids encodingthe antibodies provided herein. The cells in the kit can be maintained under appropriate storage conditions until ready to use.

[0328] Also provided herein are panels of antibodies that immunospecifically bind to an IL13Ra2 antigen. In specific embodiments, provided herein are panels of antibodies having different association rate constants, different dissociation rate constants, different affinities for IL13Ra2 antigen, and / or different specificities for an IL13Ra2 antigen. In certain embodiments, provided herein are panels of about 10, preferably about 25, about 50, about 75, about 100, about 125, about 150, about 175, about 200, about 250, about 300, about 350, about 400, about 450, about 500, about 550, about 600, about 650, about 700, about 750, about 800, about 850, about 900, about 950, or about 1000 antibodies or more. Panels of antibodies can be used, for example, in 96 well or 384 well plates, such as for assays such as ELISAs.

[0329] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, suitable methods and materials are described herein.

[0330] As used herein, numerical values are often presented in a range format throughout this document. The use of a range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention unless the context clearly indicates otherwise. Accordingly, the use of a range expressly includes all possible subranges, all individual numerical values within that range, and all numerical values or numerical ranges including integers within such ranges and fractions of the values or the integers within ranges unless the context clearly indicates otherwise. This construction applies regardless of the breadth of the range and in all contexts throughout this patent document. Thus, for example, reference to a range of 90-100% includes 91-99%, 92-98%, 93-95%, 91-98%, 91-97%, 91-96%, 91-95%, 91-94%, 91-93%, and so forth. Reference to a range of 90-100% also includes 91%, 92%, 93%, 94%, 95%, 95%, 97%, etc., as well as 91.1%, 91.2%, 91.3%, 91.4%, 91.5%, etc., 92.1%, 92.2%, 92.3%, 92.4%, 92.5%, etc., and so forth.

[0331] In addition, reference to a range of 1-3, 3-5, 5-10, 10-20, 20-30, 30-40, 40-50, 50- 60, 60-70, 70-80, 80-90, 90-100, 100-110, 110-120, 120-130, 130-140, 140-150, 150-160, 160-170, 170-180, 180-190, 190-200, 200-225, 225-250 includes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc. In a further example, reference to a range of 25-250, 250-500, 500-1,000, 1,000-2,500, 2,500-5,000, 5,000-25,000, 25,000-50,000 includes any numerical value or range within or encompassing such values, e.g., 25, 26, 27, 28, 29. ..250, 251, 252, 253, 254. ..500, 501, 502, 503, 504..., etc.

[0332] As also used herein a series of ranges are disclosed throughout this document. The use of a series of ranges includes combinations of the upper and lower ranges to provide another range. This construction applies regardless of the breadth of the range and in all contexts throughout this patent document. Thus, for example, reference to a series of ranges such as 5-10, 10-20, 20-30, 30-40, 40-50, 50-75, 75-100, 100-150, includes ranges such as 5- 20, 5-30, 5-40, 5-50, 5-75, 5-100, 5-150, and 10-30, 10-40, 10-50, 10-75, 10-100, 10-150, and 20-40, 20-50, 20-75, 20-100, 20-150, and so forth.

[0333] It is understood that modifications which do not substantially affect the activity of the various embodiments described herein are also provided within the definition of the subject matter described herein. Accordingly, the following examples are intended to illustrate but not limit the present disclosure.6. EMBODIMENTS

[0334] The present disclosure encompasses the following non-limiting embodiments:

[0335] 1. An antibody or fragment thereof that binds to IL13Ra2, wherein the antibody or fragment thereof comprises any one or more of (i)-(iii):(i) a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:25 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:26; or(ii) a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:48 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:49; or(iii) a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:73 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:74.

[0336] 2. The antibody or fragment thereof of embodiment 1, wherein the antibody or fragment thereof comprises(a) a VH region comprising:(1) a VH CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 1, 2, 3, 4, and 5;(2) a VH CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 6, 7, 8, 9, and 10; and(3) a VH CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 11, 12, 13, and 14; and(b) a VL region comprising:(1) a VL CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 15, 16, 17, and 18;(2) a VL CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 19, 20, and 21; and(3) a VL CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 22, 23, and 24.

[0337] 3. The antibody or fragment thereof of embodiment 1, wherein the antibody or fragment thereof comprises any one or more of (i)-(vi):(i) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 1, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:6, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 15, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22;(ii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:2, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:7, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 12; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 16, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22;(iii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:3, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:6, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 15, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22;(iv) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NON, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:8, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 13; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 17, a VL CDR2 comprising theamino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:23;(v) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:5, a VH CDR2 comprising the amino acid sequence of SEQ ID NOV, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 14; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 18, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:21, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:24; or(vi) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 1, a VH CDR2 comprising the amino acid sequence of SEQ ID NO: 10, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 15, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22.

[0338] 4. The antibody or fragment thereof of embodiment 1, wherein the antibody or fragment thereof comprises(a) a VH region comprising:(1) a VH CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 27, 28, 29, 30, and 31;(2) a VH CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 32, 33, 34, 35, and 36; and(3) a VH CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 37, 38, 39, and 40; and(b) a VL region comprising:(1) a VL CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 41, 42, 43, and 44;(2) a VL CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 19, 20, and 21; and(3) a VL CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 45, 46, and 47.

[0339] 5. The antibody or fragment thereof of embodiment 1, wherein the antibody or fragment thereof comprises any one or more of (i)-(vi):(i) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:27, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:32, a VH CDR3comprising the amino acid sequence of SEQ ID NO:37; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:41, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45;(ii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:28, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:33, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:38; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:42, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45;(iii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:29, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:32, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:37; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:41, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45;(iv) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:30, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:34, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:39; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:43, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:46;(v) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:31, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:35, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:40; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:44, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:21, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:47; or(vi) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:27, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:36, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:37; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:41, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45.

[0340] 6. The antibody or fragment thereof of embodiment 1, wherein the antibody or fragment thereof comprises(a) a VH region comprising:(1) a VH CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 50, 51, 52, 53, and 54;(2) a VH CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 55, 56, 57, 58, and 59; and(3) a VH CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 60, 61, 62, and 63; and(b) a VL region comprising:(1) a VL CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 64, 65, 66, and 67;(2) a VL CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 68, 20, and 69; and(3) a VL CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 70, 71, and 72.

[0341] 7 The antibody or fragment thereof of embodiment 1, wherein the antibody or fragment thereof comprises any one or more of (i)-(vi):(i) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:50, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:55, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:60; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:64, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:68, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70;(ii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:51, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:56, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:61; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:65, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70;(iii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:52, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:55, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:60; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:64, a VL CDR2 comprising theamino acid sequence of SEQ ID NO:68, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70;(iv) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:53, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:57, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:62; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:66, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:71;(v) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:54, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:58, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:63; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:67, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:69, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO: 72; or(vi) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:50, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:59, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:60; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:64, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:68, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70.

[0342] 8. The antibody or fragment thereof of any one of embodiments 1 to 7, wherein the antibody or fragment thereof further comprises a framework 1 (FR1), a framework 2 (FR2), a framework 3 (FR3) and / or a framework 4 (FR4) sequence.

[0343] 9. The antibody or fragment thereof of any one of embodiments 1 to 8, wherein the antibody or fragment thereof further comprises human framework sequences, optionally a framework 1 (FR1), a framework 2 (FR2), a framework 3 (FR3) and / or a framework 4 (FR4) sequence as set forth in any one of SEQ ID NOs: 25, 26, 48, 49, 73, and 74.

[0344] 10. The antibody or fragment thereof of any one of embodiments 1 to 9, wherein the antibody or fragment thereof comprises:(i) a VH comprising the amino acid sequence of SEQ ID NO:25 and a VL comprising the amino acid sequence of SEQ ID NO:26; or(ii) a VH comprising the amino acid sequence of SEQ ID NO:48 and a VL comprising the amino acid sequence of SEQ ID NO:49; or(iii) a VH comprising the amino acid sequence of SEQ ID NO:73 and a VL comprising the amino acid sequence of SEQ ID NO:74.

[0345] 11. The antibody or fragment thereof of any one of embodiments 1 to 10, wherein the antibody or fragment thereof comprises:(i) a heavy chain comprising the amino acid sequence of SEQ ID NO:75 and a light chain comprising the amino acid sequence of SEQ ID NO:76; or(ii) a heavy chain comprising the amino acid sequence of SEQ ID NO:79 and a light chain comprising the amino acid sequence of SEQ ID NO:80; or(iii) a heavy chain comprising the amino acid sequence of SEQ ID NO:81 and a light chain comprising the amino acid sequence of SEQ ID NO:82.

[0346] 12. The antibody or fragment thereof of any one of embodiments 1-11, wherein the antibody is a monoclonal antibody.

[0347] 13. The antibody or fragment thereof of any one of embodiments 1-12, wherein the antibody is a humanized, human or chimeric antibody.

[0348] 14. The antibody or fragment thereof of any one of embodiments 1-13, which is any one of a Fab, Fab’, F(ab’)2, Fv, scFv, (scFv)2, single chain antibody molecule, dual variable region antibody, single variable region antibody, linear antibody, V region, or a multispecific antibody formed from antibody fragments.

[0349] 15. The antibody or fragment thereof of any one of embodiments 1-14, which is conjugated or recombinantly fused to a diagnostic agent, detectable agent or therapeutic agent.

[0350] 16. The antibody or fragment thereof of embodiment 15, wherein the therapeutic agent is a chemotherapeutic agent, cytotoxin, or drug.

[0351] 17. The antibody or fragment thereof of any one of embodiments 1-16, wherein the antibody is a multispecific antibody.

[0352] 18. The antibody or fragment of embodiment 17, wherein the multispecific antibody is a bispecific antibody.

[0353] 19. A binding agent that binds to essentially the same epitope as an antibody or fragment thereof of any one of embodiments 1-18.

[0354] 20. The binding agent of embodiment 19, which is an antibody or fragment thereof.

[0355] 21. The binding agent of embodiment 20, wherein the antibody is a multispecific antibody.I l l

[0356] 22. A binding agent that competes for binding to human IL13Ra2 with an antibody or fragment thereof of any one of embodiments 1-18.

[0357] 23. The binding agent of embodiment 22, wherein the binding agent is an antibody or fragment thereof.

[0358] 24. The binding agent of embodiment 23, wherein the antibody is a multispecific antibody.

[0359] 25. A polynucleotide encoding the antibody or fragment thereof of any one of embodiments 1-14 and 17-18 or the binding agent of any one of embodiments 19-24.

[0360] 26. One or more vectors comprising one or more polynucleotides of embodiment 25 or a complementary polynucleotide.

[0361] 27. A cell comprising any one or more of the antibody or fragment thereof of any one of embodiments 1-18, the binding agent of any one of embodiments 19-24, the polynucleotide of embodiment 25, or the one or more vectors of embodiment 26.

[0362] 28. A pharmaceutical composition that comprises a pharmaceutically acceptable excipient and any one or more of: the antibody or fragment thereof of any one of embodiments 1-18, the binding agent of any one of embodiments 19-24, the polynucleotide of embodiment 25, the one or more vectors of embodiment 26, or the cell of embodiment 27.

[0363] 29. A method of identifying an IL13Ra2-expressing cell, comprising contacting the cell with the antibody or fragment thereof of any one of embodiments 1-18 or the binding agent of any one of embodiments 19-24 or the pharmaceutical composition of embodiment 28.

[0364] 30. A method of reducing viability or proliferation of an IL13Ra2-expressing cell, comprising contacting the cell with the antibody or fragment thereof of any one of embodiments 1-18 or the binding agent of any one of embodiments 19-24 or the pharmaceutical composition of embodiment 28.

[0365] 31. A method of killing an IL13Ra2-expressing cell, comprising contacting the cell with the antibody or fragment thereof of any one of embodiments 1-18 or the binding agent of any one of embodiments 19-24 or the pharmaceutical composition of embodiment 28.

[0366] 32. The method of any one of embodiments 29-31, wherein the IL13Ra2- expressing cell is a cancer cell.

[0367] 33. The method of embodiment 32, wherein the cancer cell overexpresses IL13Ra2.

[0368] 34. The method of embodiment 32, wherein the cancer cell is a melanoma cell, lung cancer cell, or colorectal cancer cell.

[0369] 35. A method for treating a disease or disorder in a subject comprising administering to the subject the antibody or fragment thereof of any one of embodiments 1-18 or the binding agent of any one of embodiments 19-24, or the pharmaceutical composition of embodiment 28.

[0370] 36. The method of embodiment 35, wherein the disease or disorder is a cancer.

[0371] 37. The method of embodiment 36, wherein the cancer expresses IL13Ra2.

[0372] 38. The method of embodiment 36, wherein the cancer overexpresses IL13Ra2.

[0373] 39. The method of embodiment 36, wherein the cancer is melanoma, lung cancer, or colorectal cancer.

[0374] 40. The method of any one of embodiments 35 to 39, wherein the subject is a human subject.7. EXAMPLES

[0375] Example 1. Antibody Generation

[0376] To obtain binders for human IL13Ra2, antibody discovery was conducted by phage display and by immunization.

[0377] A. Phage Display

[0378] To obtain binders for human IL13Ra2, antibody discovery was conducted by phage display of human Fab libraries and was carried out using standard protocols. The full-length human IL13Ra2 and IL13Ra2:IL13 complex were purchased (e.g., Biotinylated Human IL- 13 (aa 21-132 with C-term His-Avi tag) at Aero IL3-H82E5, Biotinylated Human IL13Ral ECD (aa 1-343 with C-term His tag) at SinoBiological 10943-H08H-B, Biotinylated Human IL-13Ra2 ECD (aa 27-343 with C-term His-Avi tag) at Aero IL2-H82E6, and Human IL 13 (aa 1-132) at SinoBiological 10369-HNAC) or produced internally (e.g., Biotinylated Cyno IL13Ra2 ECD (aa 27-343 with C-term cleavable FcKnob-Avi tag & FcHole dummy, monovalent), Biotinylated Mouse IL13Ra2 ECD (aa 21-344 with C-term cleavable HislO- Avi tag), and Biotinylated Rat IL13Ra2 ECD (aa 24-336 with C-term cleavable HislO-Avi tag)).

[0379] Phage clones were screened for the ability to bind to biotinylated full-length human IL13Ra2, IL13Ra2:IL13 complex, or both. Briefly, Fab-formatted phage libraries were constructed using expression vectors capable of replication and expression in phage (also referred to as a phagemid). Both the heavy chain and the light chain were encoded in the same expression vector, where the heavy chain was fused to a truncated variant of the phagecoat protein pill. The light chain and heavy chain-pill fusion were expressed as separate polypeptides and assembled in the bacterial periplasm, where the redox potential enables disulfide bond formation, to form the antigen binding domain (Fab) of the candidate antibody.

[0380] The library was created using sequences derived from a specific human heavy chain variable domain and a specific human light chain variable domain (Vk-1). Light chain variable domains within the screened library were generated with diversity introduced into the VL CDR3 (L3), where the light chain VL CDR1 (LI) and CDR2 (L2) remained the human germline sequence. For the screened library, all three CDRs of the VH domain were diversified to match the positional amino acid frequency by CDR length found in the human antibody repertoire. The phage display heavy chain (SEQ ID NO:93) and light chain (SEQ ID NO:94) scaffolds used in the library are listed below, where an “X” represents CDR amino acids that were varied to create the library, and bold italic represents the CDR sequences that were constant.

[0381] The sequence for SEQ ID NO:93 was EVQLVESGGGLVQPGGSLRLSCAASGFTFSXXXXXWVRQAPGKGLEWVAXXXXXX XXXXXXXXXXXRFTISADTSKNTAYLQMNSLRAEDTAVYYCARXXXXXXXXXXX XXXWGQGTLVTVSSASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNS GALTSGVHTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKVEP KSC.

[0382] The sequence for SEQ ID NO: 94 wasDIQMTQSPSSLSASVGDRVTITC^ / l.S’O.S’ESAA EdWYQQKPGKAPKLLIY.SAXS’LES’GV PSRFSGSRSGTDFTLTISSLQPEDFATYYCXXXXXXXXXFGQGTKVEIKRTVAAPSVF IFPPSDSQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTY SLS STLTLSKADYEKHKVYACEVTHQGLS SPVTKSFNRGEC .

[0383] Diversity was created through mutagenesis using degenerate DNA oligonucleotide primers to introduce diversity into VL CDR3 and VH CDR1 (Hl), CDR2 (H2), and CDR3 (H3) to mimic the diversity found in the natural antibody repertoire, as described in more detail in Kunkel, TA (PNAS January 1, 1985. 82 (2) 488-492), herein incorporated by reference in its entirety. Briefly, uracil-incorporated single-stranded circular DNA was prepared from isolated phage using standard procedures, and Kunkel mutagenesis was carried out to introduce diversity to the four CDRs. Chemically-synthesized DNA was then electroporated into TGI cells, followed by recovery. Recovered cells were sub-cultured and infected with M13K07 helper phage to produce the phage library.

[0384] Phage panning was performed using standard procedures. Briefly, the first round of phage panning was performed with target immobilized on streptavidin magnetic beads which were subjected to approximately IxlO12phages from the prepared library in a volume of 1 mL in PBST-2% BSA. After a one-hour incubation, the bead-bound phage were separated from the supernatant using a magnetic stand. Beads were washed three times to remove non- specifically bound phage and were then added to ER2738 cells (5 mL) at ODeoo of approximately 0.6. After 20 minutes incubation at room temperature, infected cells were subcultured in 25 mL 2xYT + Ampicillin and M13K07 helper phage (final concentration of approximately lxlOlopfu / ml) and allowed to grow overnight at 37 °C with vigorous shaking. The next day, phage were prepared using standard procedures by PEG precipitation. Preclearance of phage specific to SAV-coated beads was performed prior to panning. The second round of panning was performed using the KingFisher magnetic bead handler with 50 or 100 nM bead-immobilized antigen (IL13Ra2, or IL13Ra2:IL13 complex) using standard procedures (100 nM antigen for round 3, 50 nM antigen for round 4). In total, 3-4 rounds of phage panning were performed to enrich in phage displaying Fabs specific for the antigen. Antigen-specific enrichment was confirmed using polyclonal ELISA and individual clones were isolated and further verified by performing monoclonal phage ELISA. DNA sequencing was used to determine the sequence of the CDRs of isolated Fab clones containing a candidate antibody.

[0385] The genes encoding heavy chain and light chain variable domains of the candidate antibodies were cloned separately into mammalian expression vectors for expression as full- length IgGs in mammalian cells.

[0386] For the full-length IgGs, the heavy chain constant regions (e.g., CHI = regular text; Hinge = italicized text; CH2 = bold text; and CH3 = underline text) included the following amino acid sequence: ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGVHTFPAVL QSSGLYSLSSVVTVPSSSLGTQTYICNVNHI<PSNTI<VDI<I<VEPI<SC / JA 7 / 7C 7JAP ELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHN AKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKA KGOPREPQVYTLPPSRDELTKNOVSLTCLVKGFYPSDIAVEWESNGOPENNYKTTPP VLDSDGSFFLYSKLTVDKSRWOOGNVFSCSVMHEALHNHYTQKSLSLSPGK (SEP ID NO:95).

[0387] For the full-length IgGs, the light chain constant region (e.g., CL) included the following amino acid sequence:RTVAAPSVFIFPPSDSQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVT EQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO:96).

[0388] The IgG antibodies were purified from culture supernatant using Protein A resin.

[0389] Using this method, a total of 19 IL13Ra2 binders were identified.

[0390] B. Immunization

[0391] To obtain binders for the human IL13Ra2 antigen (full-length human IL13Ra2 or IL13Ra2:IL13 complex), antibody discovery was conducted by immunization. Alloy mice were immunized with length human IL13Ra2 or IL13Ra2:IL13 complex.

[0392] The antigen was kept frozen at -80°C until needed for immunization. Prior to immunization, a 10 mL pre-bleed was taken and stored for determining titer from later bleeds. For immunizations, an aliquot was thawed on ice, and diluted with Complete Freund's Adjuvant (CFA). Alloy mice were primed with the antigen and boosted twice every 14 days with the same antigen and Incomplete Freund’s Adjuvant (IF A).

[0393] In one embodiment, a test bleed was t...

Claims

WHAT IS CLAIMED IS:

1. An antibody or fragment thereof that binds to IL13Ra2, wherein the antibody or fragment thereof comprises any one or more of (i)-(iii):(i) a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:25 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:26; or(ii) a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:48 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:49; or(iii) a VH CDR1, a VH CDR2, and a VH CDR3 as set forth in a VH comprising the amino acid sequence of SEQ ID NO:73 and a VL CDR1, a VL CDR2, and a VL CDR3 as set forth in a VL comprising the amino acid sequence of SEQ ID NO:74.

2. The antibody or fragment thereof of claim 1, wherein the antibody or fragment thereof comprises(a) a VH region comprising:(1) a VH CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 1, 2, 3, 4, and 5;(2) a VH CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 6, 7, 8, 9, and 10; and(3) a VH CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 11, 12, 13, and 14; and(b) a VL region comprising:(1) a VL CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 15, 16, 17, and 18;(2) a VL CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 19, 20, and 21; and(3) a VL CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 22, 23, and 24.

3. The antibody or fragment thereof of claim 1, wherein the antibody or fragment thereof comprises any one or more of (i)-(vi):(i) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 1, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:6, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 15, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22;(ii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:2, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:7, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 12; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 16, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22;(iii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:3, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:6, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 15, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22;(iv) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NON, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:8, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 13; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 17, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:23;(v) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:5, a VH CDR2 comprising the amino acid sequence of SEQ ID NOV, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 14; and a VL region comprising aVL CDR1 comprising the amino acid sequence of SEQ ID NO: 18, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:21, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:24; or(vi) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO: 1, a VH CDR2 comprising the amino acid sequence of SEQ ID NO: 10, a VH CDR3 comprising the amino acid sequence of SEQ ID NO: 11; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO: 15, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:22.

4. The antibody or fragment thereof of claim 1, wherein the antibody or fragment thereof comprises(a) a VH region comprising:(1) a VH CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 27, 28, 29, 30, and 31;(2) a VH CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 32, 33, 34, 35, and 36; and(3) a VH CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 37, 38, 39, and 40; and(b) a VL region comprising:(1) a VL CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 41, 42, 43, and 44;(2) a VL CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 19, 20, and 21; and(3) a VL CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 45, 46, and 47.

5. The antibody or fragment thereof of claim 1, wherein the antibody or fragment thereof comprises any one or more of (i)-(vi):(i) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:27, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:32, a VHCDR3 comprising the amino acid sequence of SEQ ID NO:37; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:41, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45;(ii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:28, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:33, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:38; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:42, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45;(iii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:29, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:32, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:37; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:41, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45;(iv) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:30, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:34, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:39; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:43, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:46;(v) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:31, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:35, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:40; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:44, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:21, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:47; or(vi) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:27, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:36, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:37; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:41, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 19, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:45.

6. The antibody or fragment thereof of claim 1, wherein the antibody or fragment thereof comprises(a) a VH region comprising:(1) a VH CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 50, 51, 52, 53, and 54;(2) a VH CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 55, 56, 57, 58, and 59; and(3) a VH CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 60, 61, 62, and 63; and(b) a VL region comprising:(1) a VL CDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 64, 65, 66, and 67;(2) a VL CDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 68, 20, and 69; and(3) a VL CDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOs: 70, 71, and 72.

7. The antibody or fragment thereof of claim 1, wherein the antibody or fragment thereof comprises any one or more of (i)-(vi):(i) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:50, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:55, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:60; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:64, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 68, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70;(ii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:51, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:56, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:61; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:65, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70;(iii) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:52, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:55, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:60; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:64, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 68, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70;(iv) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:53, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:57, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:62; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:66, a VL CDR2 comprising the amino acid sequence of SEQ ID NO:20, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:71;(v) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:54, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:58, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:63; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:67, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 69, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO: 72; or(vi) a VH region comprising a VH CDR1 comprising the amino acid sequence of SEQ ID NO:50, a VH CDR2 comprising the amino acid sequence of SEQ ID NO:59, a VH CDR3 comprising the amino acid sequence of SEQ ID NO:60; and a VL region comprising a VL CDR1 comprising the amino acid sequence of SEQ ID NO:64, a VL CDR2 comprising the amino acid sequence of SEQ ID NO: 68, and a VL CDR3 comprising the amino acid sequence of SEQ ID NO:70.

8. The antibody or fragment thereof of any one of claims 1 to 7, wherein the antibody or fragment thereof further comprises a framework 1 (FR1), a framework 2 (FR2), a framework 3 (FR3) and / or a framework 4 (FR4) sequence.

9. The antibody or fragment thereof of any one of claims 1 to 8, wherein the antibody or fragment thereof further comprises human framework sequences, optionally a framework 1 (FR1), a framework 2 (FR2), a framework 3 (FR3) and / or a framework 4 (FR4) sequence as set forth in any one of SEQ ID NOs: 25, 26, 48, 49, 73, and 74.

10. The antibody or fragment thereof of any one of claims 1 to 9, wherein the antibody or fragment thereof comprises:(i) a VH comprising the amino acid sequence of SEQ ID NO:25 and a VL comprising the amino acid sequence of SEQ ID NO:26; or(ii) a VH comprising the amino acid sequence of SEQ ID NO:48 and a VL comprising the amino acid sequence of SEQ ID NO:49; or(iii) a VH comprising the amino acid sequence of SEQ ID NO:73 and a VL comprising the amino acid sequence of SEQ ID NO:74.

11. The antibody or fragment thereof of any one of claims 1 to 10, wherein the antibody or fragment thereof comprises:(i) a heavy chain comprising the amino acid sequence of SEQ ID NO:75 and a light chain comprising the amino acid sequence of SEQ ID NO:76; or(ii) a heavy chain comprising the amino acid sequence of SEQ ID NO:79 and a light chain comprising the amino acid sequence of SEQ ID NO:80; or(iii) a heavy chain comprising the amino acid sequence of SEQ ID NO:81 and a light chain comprising the amino acid sequence of SEQ ID NO:82.

12. The antibody or fragment thereof of any one of claims 1-11, wherein the antibody is a monoclonal antibody.

13. The antibody or fragment thereof of any one of claims 1-12, wherein the antibody is a humanized, human or chimeric antibody.

14. The antibody or fragment thereof of any one of claims 1-13, which is any one of a Fab, Fab’, F(ab’)2, Fv, scFv, (scFv)2, single chain antibody molecule, dual variable region antibody, single variable region antibody, linear antibody, V region, or a multispecific antibody formed from antibody fragments.

15. The antibody or fragment thereof of any one of claims 1-14, which is conjugated or recombinantly fused to a diagnostic agent, detectable agent or therapeutic agent.

16. The antibody or fragment thereof of claim 15, wherein the therapeutic agent is a chemotherapeutic agent, cytotoxin, or drug.

17. The antibody or fragment thereof of any one of claims 1-16, wherein the antibody is a multispecific antibody.

18. The antibody or fragment of claim 17, wherein the multispecific antibody is a bispecific antibody.

19. A binding agent that binds to essentially the same epitope as an antibody or fragment thereof of any one of claims 1-18.

20. The binding agent of claim 19, which is an antibody or fragment thereof.

21. The binding agent of claim 20, wherein the antibody is a multispecific antibody.

22. A binding agent that competes for binding to human IL13Ra2 with an antibody or fragment thereof of any one of claims 1-18.

23. The binding agent of claim 22, wherein the binding agent is an antibody or fragment thereof.

24. The binding agent of claim 23, wherein the antibody is a multispecific antibody.

25. A polynucleotide encoding the antibody or fragment thereof of any one of claims 1-14 and 17-18 or the binding agent of any one of claims 19-24.

26. One or more vectors comprising one or more polynucleotides of claim 25 or a complementary polynucleotide.

27. A cell comprising any one or more of the antibody or fragment thereof of any one of claims 1-18, the binding agent of any one of claims 19-24, the polynucleotide of claim 25, or the one or more vectors of claim 26.

28. A pharmaceutical composition that comprises a pharmaceutically acceptable excipient and any one or more of: the antibody or fragment thereof of any one of claims 1-18, the binding agent of any one of claims 19-24, the polynucleotide of claim 25, the one or more vectors of claim 26, or the cell of claim 27.

29. A method of identifying an IL13Ra2-expressing cell, comprising contacting the cell with the antibody or fragment thereof of any one of claims 1-18 or the binding agent of any one of claims 19-24 or the pharmaceutical composition of claim 28.

30. A method of reducing viability or proliferation of an IL13Ra2-expressing cell, comprising contacting the cell with the antibody or fragment thereof of any one of claims 1- 18 or the binding agent of any one of claims 19-24 or the pharmaceutical composition of claim 28.

31. A method of killing an IL13Ra2-expressing cell, comprising contacting the cell with the antibody or fragment thereof of any one of claims 1-18 or the binding agent of any one of claims 19-24 or the pharmaceutical composition of claim 28.

32. The method of any one of claims 29-31, wherein the IL13Ra2-expressing cell is a cancer cell.

33. The method of claim 32, wherein the cancer cell overexpresses IL13Ra2.

34. The method of claim 32, wherein the cancer cell is a melanoma cell.

35. A method for treating a disease or disorder in a subject comprising administering to the subject the antibody or fragment thereof of any one of claims 1-18 or the binding agent of any one of claims 19-24, or the pharmaceutical composition of claim 28.

36. The method of claim 35, wherein the disease or disorder is a cancer.

37. The method of claim 36, wherein the cancer expresses IL13Ra2.

38. The method of claim 36, wherein the cancer overexpresses IL13Ra2.

39. The method of claim 36, wherein the cancer is melanoma.

40. The method of any one of claims 35 to 39, wherein the subject is a human subject.

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