Anti-c-Met antibody and anti-c-Met antibody-cytotoxic drug conjugate and pharmaceutical use thereof

1. An antibody or antigen-binding fragment thereof that specifically binds to c-Met, comprising an antibody heavy chain variable region comprising an HCDR1 of SEQ ID NO: 6, an HCDR2 of SEQ ID NO: 7 and an HCDR3 of SEQ ID NO: 8;

and

an antibody light chain variable region comprising an LCDR1 of SEQ ID NO: 9 or SEQ ID NO:12, an LCDR2 of SEQ ID NO: 10 and an LCDR3 of SEQ ID NO: 11.

2. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 1 , wherein the antibody or the antigen-binding fragment thereof is a murine antibody or a fragment thereof.

3. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 2 , wherein the heavy chain variable region of the murine antibody comprises SEQ ID NO: 4 and the light chain variable region of the murine antibody comprises SEQ ID NO: 5.

4. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 1 , wherein the antibody or the antigen-binding fragment thereof is a chimeric antibody or a humanized antibody, or a fragment thereof.

5. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 4 being a humanized antibody, wherein the humanized antibody heavy chain variable region comprises heavy chain framework regions having FR1, FR2, FR3 and FR4 of the human germline heavy chain IGHV 3-33*01.

6. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 5 , wherein the humanized antibody comprises a heavy chain variable region having an amino acid sequence selected from the group consisting of SEQ ID NOs: 13, 14 and 15.

7. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 4 being a humanized antibody, wherein the humanized antibody light chain variable region comprises light chain framework regions having FR1, FR2, FR3 and FR4 of the human germline light chain IGKV085 or IGKV4-1*01.

8. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 7 , wherein the humanized antibody comprises a light chain variable region having an amino acid sequence selected from the group consisting of SEQ ID NOs: 16, 17 and 18.

9. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 1 , comprising a combination of a heavy chain variable region amino acid sequence and a light chain variable region amino acid sequence selected from any one of (a) to (c):

(a) Heavy chain variable region sequence of SEQ ID NO: 13, and light chain variable region sequence of SEQ ID NO: 16;

(b) Heavy chain variable region sequence of SEQ ID NO: 14, and light chain variable region sequence of SEQ ID NO: 17; and

(c) Heavy chain variable region sequence of SEQ ID NO: 15, and light chain variable region sequence of SEQ ID NO: 18.

10. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 4 being a humanized antibody, wherein the heavy chain constant region of the humanized antibody comprises a constant region derived from human IgG1, or a variant thereof, human IgG2, or a variant thereof, human IgG3, or a variant thereof, or human IgG4, or a variant thereof.

11. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 10 , comprising a full length heavy chain sequence selected from the group consisting of SEQ ID NOs: 23, 24 and 25.

12. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 4 being a humanized antibody, wherein the light chain constant region of the humanized antibody comprises a constant region selected from the group consisting of human κ and human λ, or a variant thereof.

13. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 12 , comprising a full-length light chain sequence selected from the group consisting of SEQ ID NOs: 26, 27 and 28.

14. The antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according claim 4 being a humanized antibody, wherein the humanized antibody comprises a combination of a full-length light chain sequence and a full-length heavy chain selected from the group consisting of:

Ab-9, comprising a heavy chain amino acid sequence of SEQ ID NO: 23 and a light chain amino acid sequence of SEQ ID NO: 26;

Ab-10, comprising a heavy chain amino acid sequence of SEQ ID NO: 24 and a light chain amino acid sequence of SEQ ID NO: 27; and

Ab-11, comprising a heavy chain amino acid sequence of SEQ ID NO: 25 and a light chain amino acid sequence of SEQ ID NO: 28.

15. A nucleic acid molecule encoding the antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 1 .

16. An expression vector comprising the nucleic acid molecule according to claim 15 .

17. A host cell transformed with the expression vector according to claim 16 .

18. A pharmaceutical composition comprising the antibody or the antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 1 , and one or more pharmaceutically acceptable excipients, diluents or carriers.

19. An antibody-cytotoxic drug conjugate of formula (I) or a pharmaceutically acceptable salt or solvate thereof:

Ab −[( L 2 ) t−L 1 −D )] y   (I)

wherein:

D is a drug unit;

L 1 and L 2 are linker units;

t is 0 or 1;

y is 1-8; and

Ab is the antibody or antigen-binding fragment thereof that specifically binds to c-Met receptor according to claim 1 .

20. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 19 , wherein -L 2 -comprises formula (-L 2 -):

wherein:

X 1 is selected from the group consisting of hydrogen, halogen, hydroxyl, cyano, alkyl, alkoxy and cycloalkyl;

X 2 is selected from the group consisting of alkyl, cycloalkyl and heterocyclyl;

m is 0, 1, 2, 3, 4 or 5; and

S is a sulfur atom.

21. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 19 , wherein the drug unit D is a cytotoxic agent selected from the group consisting of toxins, chemotherapeutic agents, antibiotics, radioisotopes and nucleolytic enzymes.

22. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 19 , wherein D is formula (D):

or a tautomer, mesomer, racemate, enantiomer, or diastereomer thereof, or mixtures thereof, or a pharmaceutically acceptable salt thereof;

wherein:

R 1 -R 7 are each selected from the group consisting of hydrogen, halogen, hydroxyl, cyano, alkyl, alkoxy and cycloalkyl;

R 8 -R 11 are each optionally selected from the group consisting of hydrogen, halogen, alkenyl, alkyl, alkoxy and cycloalkyl;

or any two of R 8 -R 11 form a cycloalkyl, and the rest are each selected from the group consisting of hydrogen, alkyl and cycloalkyl;

R 12 -R 13 are each selected from the group consisting of hydrogen, alkyl and halogen;

R 14 is selected from the group consisting of aryl and heteroaryl, wherein the aryl or heteroaryl is optionally further substituted by a substituent group selected from the group consisting of hydrogen, halogen, hydroxy, alkyl, alkoxy and cycloalkyl;

R 15 is selected from the group consisting of halogen, alkenyl, alkyl, cycloalkyl and COOR 17 ;

R 16 is selected from the group consisting of hydrogen, halogen, hydroxy, cyano, alkyl, alkoxy and cycloalkyl; and

R 17 is selected from the group consisting of hydrogen, alkyl and alkoxy.

23. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 22 , wherein L 2 comprises a linker selected from the group consisting of valine-citrulline, 6-maleimido-caproyl, P-aminobenzyloxycarbonyl and 6-maleimido-caproyl-P-aminobenzyloxycarbonyl.

24. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 19 , wherein D is a maytansinoid alkaloid.

25. The antibody-cytotoxic drug conjugate or the pharmaceutically acceptable salt or solvate thereof according to claim 24 , wherein L 2 is selected from the group consisting of N-succinimidyl 4-(2-pyridylthio) valerate (SPP), N-succinimidyl 4-(N-maleimidomethyl)-cyclohexane-1-Carboxylic acid ester (SMCC), and N-succinimidyl (4-iodo-acetyl) aminobenzoate (SIAB).

26. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 19 , wherein D is a camptothecin alkaloid.

27. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 26 , wherein L 2 is a linker selected from the group consisting of valine-citrulline, 6-maleimido-caproyl, P-aminobenzyloxycarbonyl or 6-maleimido-caproyl-P-aminobenzyloxycarbonyl.

28. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 19 , which is a conjugated drug of formula (II) or a pharmaceutically acceptable salt or solvate thereof:

wherein:

R 2 -R 7 are each selected from the group consisting of hydrogen, halogen, hydroxyl, cyano, alkyl, alkoxy and cycloalkyl;

R 8 -R 11 are each optionally selected from the group consisting of hydrogen, halogen, alkenyl, alkyl, alkoxy and cycloalkyl;

or any two of R 8 -R 11 form a cycloalkyl, and the rest are each selected from the group consisting of hydrogen, alkyl and cycloalkyl;

R 12 -R 13 are each selected from the group consisting of hydrogen, alkyl and halogen;

R 14 is selected from the group consisting of aryl and heteroaryl, wherein the aryl or heteroaryl is optionally further substituted by a substituent group selected from the group consisting of hydrogen, halogen, hydroxy, alkyl, alkoxy and cycloalkyl;

R 15 is selected from the group consisting of halogen, alkenyl, alkyl, cycloalkyl and COOR 17 ;

R 16 is selected from the group consisting of hydrogen, halogen, hydroxy, cyano, alkyl, alkoxy and cycloalkyl; and

R 17 is selected from the group consisting of hydrogen, alkyl and alkoxy.

29. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 19 , which is a conjugated drug of formula (III) or a pharmaceutically acceptable salt or solvate thereof:

wherein:

R 2 -R 7 are each selected from the group consisting of hydrogen, halogen, hydroxyl, cyano, alkyl, alkoxy and cycloalkyl;

R 8 -R 11 are each optionally selected from the group consisting of hydrogen, halogen, alkenyl, alkyl, alkoxy and cycloalkyl;

or any two of R 8 -R 11 form a cycloalkyl, and the rest are each selected from the group consisting of hydrogen, alkyl and cycloalkyl;

R 12 -R 13 are each selected from the group consisting of hydrogen, alkyl and halogen;

R 14 is selected from the group consisting of aryl and heteroaryl, wherein the aryl or heteroaryl is optionally further substituted by a substituent group selected from the group consisting of hydrogen, halogen, hydroxy, alkyl, alkoxy and cycloalkyl;

R 15 is selected from the group consisting of halogen, alkenyl, alkyl, cycloalkyl and COOR 17 ;

R 16 is selected from the group consisting of hydrogen, halogen, hydroxy, cyano, alkyl, alkoxy and cycloalkyl;

R 17 is selected from the group consisting of hydrogen, alkyl and alkoxy; and

n is 3, 4, 5 or 6.

30. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 19 , which is a conjugated drug of formula (IV) or a pharmaceutically acceptable salt or solvate thereof:

wherein:

R 2 -R 7 are each selected from the group consisting of hydrogen, halogen, hydroxyl, cyano, alkyl, alkoxy and cycloalkyl;

R 8 -R 11 are each optionally selected from the group consisting of hydrogen, halogen, alkenyl, alkyl, alkoxy and cycloalkyl;

or any two of R 8 -R 11 form a cycloalkyl, and the rest are each selected from the group consisting of hydrogen, alkyl and cycloalkyl;

R 12 -R 13 are each selected from the group consisting of hydrogen, alkyl and halogen;

R 14 is selected from the group consisting of aryl and heteroaryl, wherein the aryl or heteroaryl is optionally further substituted by a substituent group selected from the group consisting of hydrogen, halogen, hydroxy, alkyl, alkoxy and cycloalkyl;

R 15 is selected from the group consisting of halogen, alkenyl, alkyl, cycloalkyl and COOR 17 ;

R 16 is selected from the group consisting of hydrogen, halogen, hydroxy, cyano, alkyl, alkoxy and cycloalkyl;

R 17 is selected from the group consisting of hydrogen, alkyl and alkoxy;

n is 3, 4, 5 or 6;

X 1 is selected from the group consisting of hydrogen, halogen, hydroxyl, cyano, alkyl, alkoxy and cycloalkyl;

X 2 is selected from the group consisting of alkyl, cycloalkyl and heterocyclyl; and

m is 0, 1, 2, 3, 4 or 5.

31. The antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 19 , which is a conjugated drug of formula (V) or a pharmaceutically acceptable salt or solvate thereof:

wherein:

n is 3, 4, 5 or 6;

X 1 is selected from the group consisting of hydrogen, halogen, hydroxyl, cyano, alkyl, alkoxy and cycloalkyl;

X 2 is selected from the group consisting of alkyl, cycloalkyl and heterocyclyl; and

m is 0, 1, 2, 3, 4 or 5.

32. An antibody-cytotoxic drug conjugate selected from the group consisting of:

or a pharmaceutically acceptable salt or solvate thereof, wherein

y is 1-8;

Ab-9 is a humanized antibody comprising a heavy chain amino acid sequence of SEQ ID NO: 23 and a light chain amino acid sequence of SEQ ID NO: 26;

Ab-10 is a humanized antibody comprising a heavy chain amino acid sequence of SEQ ID NO: 24 and a light chain amino acid sequence of SEQ ID NO: 27; and

Ab-11 is a humanized antibody comprising a heavy chain amino acid sequence of SEQ ID NO: 25 and a light chain amino acid sequence of SEQ ID NO: 28.

33. A process of preparing the conjugated drug of formula (V) or the pharmaceutically acceptable salt or solvate thereof according to claim 31 , comprising:

wherein a compound of the general formula (Ab-L2) is reacted with a compound of the general formula (L1-D) in an organic solvent to obtain a compound of the general formula (V);

wherein

x is 0-5.

34. A pharmaceutical composition comprising the antibody-cytotoxic drug conjugate of formula (I) or the pharmaceutically acceptable salt or solvate thereof according to claim 19 , and one or more pharmaceutically acceptable excipients, diluents or carriers.

35. A method of treating a c-Met-mediated disease or condition, the method comprising administering to a subject in need thereof a pharmaceutical composition according to claim 18 , wherein the c-Met-mediated disease or condition is a cancer selected from the group consisting of gastric cancer, pancreatic cancer, lung cancer, intestinal cancer, kidney cancer, and melanoma.

36. A method of treating a c-Met-mediated disease or condition, the method comprising administering to a subject in need thereof a pharmaceutical composition according to claim 34 , wherein the c-Met-mediated disease or condition is a cancer selected from the group consisting of gastric cancer, pancreatic cancer, lung cancer, intestinal cancer, kidney cancer, and melanoma.