Anti-CD73 antibodies and compositions

1. An anti-CD73 antibody or an antigen-binding portion thereof, wherein said antibody comprises the H-CDR1-3 and L-CDR1-3 amino acid sequences of:

a) SEQ ID NOs: 17-22, respectively;

b) SEQ ID NOs: 23-28, respectively;

c) SEQ ID NOs: 29-34, respectively; or

d) SEQ ID NOs: 35-40, respectively.

2. The anti-CD73 antibody or antigen-binding portion of claim 1 , wherein said antibody comprises a heavy chain variable domain amino acid sequence and a light chain variable domain amino acid sequence that are at least 90% identical to the amino acid sequences of:

a) SEQ ID NOs: 9 and 13, respectively;

b) SEQ ID NOs: 10 and 14, respectively;

c) SEQ ID NOs: 11 and 15, respectively; or

d) SEQ ID NOs: 12 and 16, respectively.

3. The anti-CD73 antibody or antigen-binding portion of claim 1 , wherein said antibody comprises a heavy chain variable domain and a light chain variable domain comprising the amino acid sequences of:

a) SEQ ID NOs: 9 and 13, respectively;

b) SEQ ID NOs: 10 and 14, respectively;

c) SEQ ID NOs: 11 and 15, respectively; or

d) SEQ ID NOs: 12 and 16, respectively.

4. The anti-CD73 antibody or antigen-binding portion of claim 1 , wherein the antibody or antigen-binding portion has at least one property selected from:

a) inhibits the activity of soluble CD73 in vitro;

b) inhibits the activity of CD73 on Calu-6 cells in vitro;

c) inhibits the activity of CD73 on H292 cells in vitro;

d) specifically binds to human and cynomolgus CD73 expressed on CHO-S cells;

e) binds to the ECD of human CD73 with a K D of 1 nM or less as measured by SPR;

f) binds to the ECD of cynomolgus CD73 with a K D of 0.7 nM or less as measured by SPR;

g) binds an epitope on the CD73 homodimer in a manner that gives rise to a 1:1 complex;

h) inhibits soluble CD73 activity more effectively than oleclumab in vitro;

i) inhibits CD73 activity on Calu-6, H292, and Cynom-K1 cells in vitro;

j) inhibits CD73 activity on Calu-6, NCI-H1775, KYSE-30, and Capan-2 cells in vitro;

k) restores proliferation of CD4 + T cells in vitro; and

l) does not reduce levels of CD73 in H292 cells in vitro by more than 25%.

5. The anti-CD73 antibody of claim 1 , wherein the antibody is an IgG 1 and wherein one or both of the amino acid residues at positions 234 and 235 are mutated from Leu to Ala, wherein the positions are numbered according to the Eu numbering scheme.

6. An anti-CD73 antibody that comprises:

a) a heavy chain (HC) comprising the amino acid sequences of SEQ ID NOs: 9 and 41 and a light chain (LC) comprising the amino acid sequences of SEQ ID NOs: 13 and 42;

b) an HC comprising the amino acid sequences of SEQ ID NOs: 10 and 41 and an LC comprising the amino acid sequences of SEQ ID NOs: 14 and 42;

c) an HC comprising the amino acid sequences of SEQ ID NOs: 11 and 41 and an LC comprising the amino acid sequences of SEQ ID NOs: 15 and 42; or

d) an HC comprising the amino acid sequences of SEQ ID NOs: 12 and 41 and an LC comprising the amino acid sequences of SEQ ID NOs: 16 and 42.

7. A pharmaceutical composition comprising the anti-CD73 antibody or antigen-binding portion of claim 1 and a pharmaceutically acceptable excipient.

8. The pharmaceutical composition of claim 7 , further comprising an immunostimulatory agent, a vaccine, a chemotherapeutic agent, an anti-neoplastic agent, an anti-angiogenic agent, a tyrosine kinase inhibitor, or a CD73 pathway inhibitor.

9. An isolated nucleic acid molecule comprising a nucleotide sequence that encodes the heavy chain, a nucleotide sequence that encodes the light chain, or both, of the anti-CD73 antibody or antigen-binding portion of claim 1 .

10. The isolated nucleic acid molecule of claim 9 , wherein said nucleic acid molecule comprises the nucleotide sequence of any one of SEQ ID NOs: 1-8.

11. A vector comprising the isolated nucleic acid molecule of claim 9 , wherein said vector further comprises an expression control sequence.

12. A host cell comprising a nucleotide sequence that encodes the heavy chain, and a nucleotide sequence that encodes the light chain, of the anti-CD73 antibody or antigen-binding portion of claim 1 .

13. A method for producing an anti-CD73 antibody or an antigen-binding portion thereof, comprising providing a host cell according to claim 12 , culturing said host cell under conditions suitable for expression of the antibody or portion, and isolating the resulting antibody or portion.

14. A bi-specific binding molecule comprising the antigen-binding portion of one or two distinct anti-CD73 antibodies according to claim 1 .

15. A method for:

a) decreasing CD73 activity;

b) increasing CD4 + T cell proliferation; and/or

c) stimulating the immune system,

in a patient in need thereof, comprising administering to said patient a therapeutically effective amount of the anti-CD73 antibody or antigen-binding portion of claim 1 .

16. A method for treating cancer in a patient, comprising administering to said patient a therapeutically effective amount of the anti-CD73 antibody or antigen-binding portion of claim 1 .

17. The method of claim 16 , wherein the cancer originates in a tissue selected from the group consisting of skin, lung, intestine, colon, ovary, brain, prostate, kidney, soft tissues, the hematopoietic system, head and neck, liver, bone, bladder, breast, stomach, uterus, cervix, and pancreas.

18. The method of claim 16 , wherein the cancer is melanoma, head and neck cancer, breast cancer, bladder cancer, non-small cell lung cancer, pancreatic cancer, ovarian cancer, renal cell carcinoma, prostate cancer, colorectal cancer, cholangiocarcinoma, thyroid cancer, or testicular cancer.

19. The method of claim 16 , further comprising administering to the patient an immunostimulatory agent, a vaccine, a chemotherapeutic agent, an anti-neoplastic agent, an anti-angiogenic agent, a tyrosine kinase inhibitor, a CD73 pathway inhibitor, or radiation therapy.

20. An anti-CD73 antibody that comprises a heavy chain (HC) comprising the amino acid sequences of SEQ ID NOs: 11 and 41 and a light chain (LC) comprising the amino acid sequences of SEQ ID NOs: 15 and 42.