Anti-cldn6 and Anti-cd3 multispecific antibodies and methods of use

HK40137767APending Publication Date: 2026-09-18BEONE MEDICINES I GMBH
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Patent Information

Application Number
HK62026125407
Authority / Receiving Office
HK · HK
Patent Type
Applications
Current Assignee / Owner
Priority Date
2023-03-06
Filing Date
2026-06-27
Publication Date
2026-09-18
Estimated Expiration
2044-03-04

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Abstract

The present disclosure provides for multi-specific antibodies and antigen-binding fragments thereof that bind to human CLDN6 and CD3, a pharmaceutical composition comprising said antibody or antigen-binding fragments thereof, and use of the multi-specific antibody or antigen-binding fragments thereof or the composition for treating a disease, such as cancer.
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Description

Abstract This disclosure provides multispecific antibodies that bind to human CLDN6 and CD3 and their antigen-binding fragments, pharmaceutical compositions comprising said antibodies or their antigen-binding fragments, and the use of said multispecific antibodies or their antigen-binding fragments or said compositions for treating diseases such as cancer.

Claims

CLAIMS1. A multi-specific antibody or antigen-binding fragment thereof, comprising a first antigen binding domain that specifically binds to human claudin 6 (CLDN6) and a second antigen binding domain that specifically binds to human cluster of differentiation 3 (CD3).

2. The multi-specific antibody or antigen-binding fragment of claim 1, wherein the first antigen binding domain does not bind to other claudin (CLDN) protein family members.

3. The multi-specific antibody or antigen-binding fragment of claim 2, wherein the first antigen binding domain does not bind to human claudin 9 (CLDN9).

4. The multi-specific antibody or antigen-binding fragment of claim 3, wherein the first antigen binding domain has high selectivity for human CLDN6 over human CLDN9.

5. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the first antigen binding domain that specifically binds to human CLDN6 comprises:(a) a heavy chain variable region that comprises (i) a heavy chain complementaritydetermining region (HCDR)1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 39, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3; and a light chain variable region that comprises: (iv) a light chain complementarity-determining region (LCDR)1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6;(b) a heavy chain variable region that comprises: (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 2, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3; and a light chain variable region that comprises :(iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6;(c) a heavy chain variable region that comprises: (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 23, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3; and a lightchain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; or(d) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 45, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3; and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6.

6. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the first antigen binding domain comprises:(a) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 43, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 44;(b) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO:7, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 8;(c) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 24, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 12;(d) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 41, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 42;(e) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 46, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 47; or(f) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 46, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 42.

7. The multi-specific antibody or antigen-binding fragment of claim 6, wherein one, two, three, four, five, six, seven, eight, nine, or ten amino acids of SEQ ID NOS: 7, 8, 12, 24, 41, 42, 43, 44, 46, or 47 have been inserted, deleted or substituted.

8. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the first antigen binding domain comprises:(a) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 44;(b) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 7, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 8;(c) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 24, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 12;(d) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 41, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 42;(e) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 46, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 47; or(f) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 46, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 42.

9. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the second antigen binding domain that specifically binds to human CD3 comprises:(a) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 75, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53;(b) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 49, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 50, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) aLCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53; or(c) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 50, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53.

10. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the second antigen binding domain comprises:(a) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 76, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 68;(b) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 54, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 55;(v) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 58, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 59;(d) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 62, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 63;(e) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 62, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 68; or(f) a heavy chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 72, and a light chain variable region having an amino acid sequence at least 90, 91, 92, 93, 94, 95, 96, 97, 98 or 99% identical to SEQ ID NO: 68.

11. The multi-specific antibody or antigen-binding fragment of claim 10, wherein one, two, three, four, five, six, seven, eight, nine, or ten amino acids of SEQ ID NOS: 54, 55, 58, 59, 62, 68, 72 or 76 have been inserted, deleted or substituted.

12. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the second antigen binding domain comprises:(a) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 76, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 68;(b) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 54, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 55;(c) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 58, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 59;(d) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 62, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 63;(e) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 62, and a light chain variable region having an amino acid sequence that comprises SEQ ID NO: 68; or(f) a heavy chain variable region having an amino acid sequence that comprises SEQ ID NO: 72, and a light chain variable region having an amino acid sequence hat comprises SEQ ID NO: 68.

13. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the second antigen binding domain comprises:(a) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 77;(b) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 66;(c) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 69; or(d) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 73.

14. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein:(a) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 2, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vii) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 49, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 50, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53;(b) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 2, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID N6O: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 50, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53; or(c) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 2, and (iii) a HCDR3having an amino acid sequence of SEQ ID NO: 3, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 75, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53.

15. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein:(a) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 23, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 49, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 50, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53;(b) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 23, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ IDNO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 50, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53; or(c) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 23, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 75 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53.

16. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein:(a) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 39, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acidsequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 49, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 50, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53;(b) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 39, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 50, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (f) a LCDR3 having an amino acid sequence of SEQ ID NO: 53; or(c) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 39, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, and (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 75, and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ IDNO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53.

17. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 39, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (f) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 75 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53.

18. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein:(a) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 45, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (ivd) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 49, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 50 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acidsequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53;(b) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 45, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 50 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53; or(c) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 45, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 75 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53.

19. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein:the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 45, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 48, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 71, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 75 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 51, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 52, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 53.

20. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises: a) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 2, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; b) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 23, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; c) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 39, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence ofSEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; or d) the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 45, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises: a) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 54, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 55; b) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 58, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 59; c) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 62, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 63; d) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 62, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68; e) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 72, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68; or f) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 76, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68.

21. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises:a) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 39, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; or and the second antigen binding domain that specifically binds to human CD3 comprises: b) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 54, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 55; c) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 58, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 59; d) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 62, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 63; e) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 62, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68; f) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 72, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68; or g) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 76, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68.

22. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises:(a) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 23, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a lightchain variable region that comprises: (ivd) a LCDR1 having an amino acid sequence of SEQ ID NO: 4, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; or(b) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 39, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; or(c) a heavy chain variable region that comprises (i) a HCDR1 having an amino acid sequence of SEQ ID NO: 1, (ii) a HCDR2 having an amino acid sequence of SEQ ID NO: 45, (iii) a HCDR3 having an amino acid sequence of SEQ ID NO: 3 and a light chain variable region that comprises: (iv) a LCDR1 having an amino acid sequence of SEQ ID NO: 40, (v) a LCDR2 having an amino acid sequence of SEQ ID NO: 5, and (vi) a LCDR3 having an amino acid sequence of SEQ ID NO: 6; and the second antigen binding domain that specifically binds to human CD3 comprises:(i) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 66;(ii) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 69;(iii) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 73; or(iv) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 77.

23. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises:(i) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 24, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 12;(ii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 41, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 42;(iii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44;(iv) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 46, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 47; or(v) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 46, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 42; and the second antigen binding domain that specifically binds to human CD3 comprises:(i) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 54, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 55;(ii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 58, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 59;(iii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 62, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 63;(iv) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 62, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68;(v) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 72, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68; or(vi) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 76, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68.

24. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises:(i) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 24, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 12;(ii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 41, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 42;(iii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44;(iv) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 46, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 47; or(v) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 46, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 42; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 72, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68.

25. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises:(i) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 24, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 12;(ii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 41, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 42;(iii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44;(iv) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 46, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 47; or(v) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 46, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 42; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 76, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68.

26. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44; and the second antigen binding domain that specifically binds to human CD3 comprises:(i) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 54, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 55;(ii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 58, and a light chain variable region (VL) that comprises SEQ ID NO: 59;(iii) a heavy chain variable region (VH) that comprises SEQ ID NO: 62, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 63;(iv) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 62, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68;(v) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 72, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68; or(vi) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 76, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68.

27. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 72, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68.

28. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44; and the second antigen binding domain that specifically binds to human CD3 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 76, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 68.

29. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises:(i) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 24, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 12;(ii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 41, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 42;(iii) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44;(iv) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 46, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 47; or(v) a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 46, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO:

42. and the second antigen binding domain that specifically binds to human CD3 comprises:(i) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 66;(ii) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 69;(iii) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 73; or(iv) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 77.

30. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44; and the second antigen binding domain that specifically binds to human CD3 comprises:(a) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 66;(b) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 69;(c) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 73; or(d) a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 77.

31. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44; and the second antigen binding domain that specifically binds to human CD3 comprises: a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 66.

32. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44; and the second antigen binding domain that specifically binds to human CD3 comprises: a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 69.

33. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44; and the second antigen binding domain that specifically binds to human CD3 comprises: a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 73.

34. The multi-specific antibody or antigen-binding fragment of claim 1, wherein: the first antigen binding domain that specifically binds to human CLDN6 comprises: a heavy chain variable region (VH) having an amino acid sequence that comprises SEQ ID NO: 43, and a light chain variable region (VL) having an amino acid sequence that comprises SEQ ID NO: 44; and the second antigen binding domain that specifically binds to human CD3 comprises: a single chain variable fragment (scFv) having an amino acid sequence that comprises SEQ ID NO: 77.

35. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, which is a monoclonal antibody, a chimeric antibody, a humanized antibody, a humanengineered antibody, a single chain antibody (scFv), a Fab fragment, a Fab’ fragment, or a F(ab’)2 fragment.

36. The multi-specific antibody or antigen-binding fragment of claim any one of the preceding claims, wherein the multi-specific antibody is a bispecific antibody.

37. The multi-specific antibody or antigen-binding fragment of claim 36, wherein the multispecific antibody is BG143P.

38. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the antibody or antigen-binding fragment thereof has antibody dependent cellular cytotoxicity (ADCC) or complement dependent cytotoxicity (CDC).

39. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the antibody or antigen-binding fragment thereof has reduced glycosylation or no glycosylation or is hypofucosylated.

40. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the antibody or antigen-binding fragment thereof comprises increased bisecting GlcNac structures.

41. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the Fc domain is an IgGl with reduced effector function.

42. The multi-specific antibody or antigen-binding fragment of any one of the preceding claims, wherein the Fc domain is an IgGl.

43. A pharmaceutical composition comprising the multi-specific antibody or antigen- binding fragment thereof, of any one of claims 1 to 42 further comprising a pharmaceutically acceptable carrier.

44. The pharmaceutical composition of claim 43, further comprising a histidine / histidine HC1, a trehalose dihydrate, and / or a polysorbate 20.

45. A method of treating cancer comprising administering to a patient in need an effective amount of the multi-specific antibody or antigen-binding fragment of claim 1 to 42.

46. The method of claim 45, wherein the cancer is a solid tumor.

47. The method of claim 45, wherein the cancer is selected from gastric cancer, colon cancer, pancreatic cancer, breast cancer, head and neck cancer, kidney cancer, liver cancer, lung cancer, small cell lung cancer, non-small cell lung cancer, ovarian cancer, skin cancer, mesothelioma, lymphoma, leukemia, myeloma, sarcoma, brain cancer, colorectal cancer, prostate cancer, cervical cancer, testicular cancer, endometrial cancer, bladder cancer, rhabdoid tumor and / or glioma.

48. The method of claim 45, wherein the multi-specific antibody or antigen-binding fragment is administered in combination with one or more additional therapeutic agent.

49. The method of claim 48, wherein the one or more therapeutic agent is selected from paclitaxel or a paclitaxel agent, docetaxel, carboplatin, topotecan, cisplatin, irinotecan, doxorubicin, lenalidomide or 5-azacytidine.

50. The method of claim 49, wherein the one or more therapeutic agent is a paclitaxel agent, lenalidomide or 5-azacytidine.

51. The method of claim 48, wherein at least one of the one or more therapeutic agent an anti- PD1 or anti-PDLl antibody.

52. The method of claim 51, wherein the anti-PDl antibody is Tislelizumab.

53. An isolated nucleic acid that encodes the multi-specific antibody or antigen-binding fragment of any one of claims 1 to 42.

54. A vector comprising the nucleic acid of claim 53.

55. A host cell comprising the nucleic acid of claim 53 or the vector of claim 54.

56. A process for producing a multi-specific antibody or antigen-binding fragment thereof comprising cultivating the host cell of claim 55 and recovering the antibody or antigen-binding fragment from the culture.

57. The multi-specific antibody or antigen-binding fragment of any one of claims 1 to 42, or the pharmaceutical composition of claim 43 or 44, for use in medicine or therapy.

58. The multi-specific antibody or antigen-binding fragment of any one of claims 1 to 42, or the pharmaceutical composition of claim 43 or 44, for use in a method for treating cancer.

59. Use of the multi-specific antibody or antigen-binding fragment of any one of claims 1 to 42 in the manufacture of a medicament for the treatment of cancer.