Fusion protein containing TGF-β receptor and medicinal uses thereof

1. A fusion protein having the general formula (I):

Ab-L-TGF-βRII ECD  (I)

wherein:

TGF-βRII ECD represents an N-terminal truncated form of the extracellular domain of TGF-βRII having a deletion of 14-26 contiguous amino acids at the N-terminus of the extracellular domain of TGF-βRIL wherein the extracellular domain of TGF-βRII comprises the amino acid sequence of SEQ ID NO: 13;

Ab represents an anti-PD-L1 antibody or antigen-binding fragment thereof, comprising:

HCDR1 of SEQ ID NO: 1;

HCDR2 of SEQ ID NO: 2;

HCDR3 of SEQ ID NO: 3;

LCDR1 of SEQ ID NO: 4;

LCDR2 of SEQ ID NO: 5; and

LCDR3 of SEQ ID NO: 6; and

L represents a linker.

2. The fusion protein according to claim 1 , wherein the N-terminal truncated form of the extracellular domain of TGF-βRII comprises a deletion of 14-21 contiguous amino acids at the N-terminus of the extracellular domain of TGF-βRII.

3. The fusion protein according to claim 1 , wherein the anti-PD-L1 antibody or antigen-binding fragment thereof is selected from the group consisting of a full length antibody, a chimeric antibody, Fab', Fab, F(ab') 2 , Fv, scFv, a bi-specific antibody, and a tri-specific antibody or mixture thereof.

4. The fusion protein according to claim 1 , wherein the anti-PD-L1 antibody or antigen-binding fragment thereof is a chimeric antibody or a functional fragment thereof, .

5. The fusion protein according to claim 4 , wherein the anti-PD-L1 antibody or antigen-binding fragment thereof is thea humanized antibody comprising a heavy chain variable region having the amino acid sequence of SEQ ID NO: 7.

6. The fusion protein according to claim 4 , wherein the anti-PD-L1 antibody or antigen-binding fragment thereof is thea humanized antibody comprising a heavy chain having the amino acid sequence of SEQ ID NO: 11.

7. The fusion protein according to claim 4 , wherein the anti-PD-L1 antibody or antigen-binding fragment thereof is mea humanized antibody comprising a light chain variable region having the amino acid sequence of SEQ ID NO: 8 or SEQ ID NO: 10.

8. The fusion protein according to claim 4 , wherein the anti-PD-L1 antibody or antigen-binding fragment thereof is mea humanized antibody comprising a light chain having the amino acid sequence of SEQ ID NO: 12.

9. The fusion protein according to claim 1 , wherein the linker has the amino acid sequence of (G 4 S)xG, wherein x is an integer of 3-6.

10. The fusion protein according to claim 1 , wherein the N-terminal truncated form of the extracellular domain of TGF-βRII consists of an amino acid sequence selected from the group consisting of SEQ ID NO: 14 and SEQ ID NO: 15, and Ab represents the anti-PD-L1 antibody having the heavy chain sequence of SEQ ID NO: 11 and the light chain sequence of SEQ ID NO:12.

11. The fusion protein according to claim 1 , wherein the N-terminal truncated form of the extracellular domain of TGF-βRII consists of an amino acid sequence selected from the group consisting of SEQ ID NO: 14, SEQ ID NO: 15, and SEQ ID NO: 16.

12. The fusion protein according to claim 11 , wherein the anti-PD-L1 antibody or antigen-binding fragment thereof comprises a heavy chain variable region having the amino acid sequence of SEQ ID NO:9, and a light chain variable region having the amino acid sequence of SEQ ID NO: 8 or SEQ ID NO: 10.

13. The fusion protein according to claim 11 , wherein the N-terminal truncated form of the extracellular domain of TGF-βRII is fused to the carboxy terminus of the heavy chain of the anti-PD-L1 antibody via the linker.

14. A pharmaceutical composition, comprising a therapeutically effective amount of the fusion protein claim 1 , and one or more pharmaceutically acceptable carrier(s), diluent(s) or excipient(s).

15. A method for treating a PD-L1-mediated tumor, comprising administering to a patient in need thereof a therapeutically effective amount of the fusion protein of claim 1 .

16. The method according to claim 15 , wherein the PD-L1-mediated tumor is selected from the group consisting of colorectal, breast, ovary, pancreas, stomach, prostate, kidney, cervix, thyroid, endometrium, uterus, bladder, neuroendocrine, head and neck, liver, nasopharynx, testis, small cell lung cancer, non-small cell lung cancer, dermatofibrosarcoma protuberans, Neck Cell carcinoma, glioblastoma, glioma, sarcoma, and mesothelioma.