Antitumor immune checkpoint regulator antagonists

1. An antitumor antagonist comprising:

a first targeting domain that specifically binds to PD-1 or LAG-3;

a second targeting domain comprising an scFv that specifically binds to TIGIT, wherein the scFv comprises an immunoglobulin heavy chain variable region (HCVR) linked to an immunoglobulin light chain variable region (LCVR) via a peptide linker comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 189-191; and

an immunoglobulin scaffold having an amino terminus and a carboxyl terminus,

wherein the first targeting domain is linked to the amino terminus of the immunoglobulin scaffold, wherein the second targeting domain is linked to the carboxyl terminus of immunoglobulin scaffold,

wherein the first targeting domain is selected from the group consisting of

(1) a PD-1 targeting domain comprising an HCVR comprising an HCDR1 having an amino acid sequence of SEQ ID NO:79, an HCDR2 having an amino acid sequence of SEQ ID NO:80, and an HCDR3 having an amino acid sequence of SEQ ID NO:81, and an LCVR comprising an LCDR1 having an amino acid sequence of SEQ ID NO:93, an LCDR2 having an amino acid sequence of SEQ ID NO:94, and an LCDR3 having an amino acid sequence of SEQ ID NO:95, and

(2) an LAG-3 targeting domain comprising an HCDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOS:163, 166, and 169, an HCDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOS:164, 167, and 170, an HCDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOS:165, 168, and 171, and an LCVR comprising an LCDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOS:172, 175, and 177, an LCDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOS:173 and 178, and an LCDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOS:174, 176 and 179, and

wherein the scFv in the second targeting domain comprises an HCDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOS:1, 6, 11, 15, 17, 20 and 23, an HCDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOS:2, 4, 7, 9, 12, 13, 16, 18, 21 and 24, an HCDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOS:3, 5, 8, 10, 14, 19, 22 and 25, an LCDR1 having an amino acid sequence selected from the group consisting of SEQ ID NOS:26, 29, 31, 33, 35, 39, 42 and 45, an LCDR2 having an amino acid sequence selected from the group consisting of SEQ ID NOS: 27, 30, 36, 37, 40, 43 and 46, and an LCDR3 having an amino acid sequence selected from the group consisting of SEQ ID NOS:28, 32, 34, 38, 41, 44 and 47.

2. The antitumor antagonist of claim 1 , wherein the HCVR of the scFv has at least 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOS:48, 50, 52, 54, 56, 58, 60, 62, 64, and 66; and

wherein the LCVR of the scFv has at least 90% identity comprising an amino acid sequence selected from the group consisting of SEQ ID NOS:49, 51, 53, 55, 57, 59, 61, 63, 65, and 67.

3. The antitumor antagonist of claim 1 , wherein the HCVR of the scFv has at least 90% identity to the amino acid sequence of SEQ ID NO:66; and

wherein the LCVR of the scFv has at least 90% identity to the amino acid sequence of SEQ ID NO:67.

4. The antitumor antagonist of claim 3 , wherein the HCVR of the scFv comprises the amino acid sequence of SEQ ID NO:66; and

wherein the LCVR of the scFv comprises the amino acid sequence of SEQ ID NO:67.

5. The antitumor antagonist of claim 1 , wherein the first targeting domain comprises:

an immunoglobulin HCVR comprising the amino acid sequence of SEQ ID NO:106; and

an immunoglobulin LCVR comprising the amino acid sequence of SEQ ID NO:107.

6. The antitumor antagonist of claim 1 , comprising:

an immunoglobulin heavy chain having the amino acid sequence of SEQ ID NO:160 or SEQ ID NO:162; and

an immunoglobulin light chain having the amino acid sequence of SEQ ID NO:161.

7. The antitumor antagonist of claim 1 , wherein the first targeting domain comprises:

an immunoglobulin HCVR having at least 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOS:180, 182, 184, and 186; and

an immunoglobulin LCVR having at least 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOS:181, 183, 185, and 187.

8. The antitumor antagonist of claim 1 , wherein the first targeting domain comprises:

an immunoglobulin HCVR having the amino acid sequence of SEQ ID NO:180; and

an immunoglobulin LCVR having the amino acid sequence of SEQ ID NO:181.

9. The antitumor antagonist of claim 1 , wherein the first targeting domain comprises:

an immunoglobulin heavy chain comprising the amino acid sequence of SEQ ID NO:192 or SEQ ID NO:193; and

an immunoglobulin light chain comprising the amino sequence of SEQ ID NO:194.

10. An antibody or antigen-binding portion thereof, comprising:

(1) an immunoglobulin HCVR comprising three HCDRs: HCDR1, HCDR2 and HCDR3,

wherein the HCDR1 comprises an amino acid sequence selected from the group consisting of SEQ ID NOS:163, 166, and 169,

wherein the HCDR2 comprises an amino acid sequence selected from the group consisting of SEQ ID NOS:164, 167, and 170,

wherein the HCDR3 comprises an amino acid sequence selected from the group consisting of SEQ ID NOS:165, 168, and 171; and

(2) an immunoglobulin LCVR comprising three LCDRs: LCDR1, LCDR2 and LCDR3,

wherein the LCDR1 comprises an amino acid sequence selected from the group consisting of SEQ ID NOS:172, 175, and 177,

wherein the LCDR2 comprises an amino acid sequence selected from the group consisting of SEQ ID NOS:173 and 178, and

wherein the LCDR3 comprises an amino acid sequence selected from the group consisting of SEQ ID NOS:174, 176 and 179, and

wherein the antibody, or the antigen-binding portion thereof, binds specifically to human LAG-3.

11. The antibody or an antigen-binding portion thereof of claim 10 , comprising:

an immunoglobulin HCVR having at least 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOS:180, 182, 184, and 186; and/or

an immunoglobulin LCVR having at least 90% identity to an amino acid sequence selected from the group consisting of SEQ ID NOS:181, 183, 185, and 187.

12. The antibody or an antigen-binding portion thereof of claim 10 , comprising:

an immunoglobulin HCVR comprising the amino acid sequence of SEQ ID NO:180; and/or

an immunoglobulin LCVR comprising the amino acid sequence of SEQ ID NO:181.

13. A method of treating a cell proliferative disorder in a subject, comprising:

administering to a subject in need thereof an effective amount of the antitumor antagonist of claim 1 .

14. A method of treating a cell proliferative disorder in a subject, comprising:

administering to a subject in need thereof an effective amount of the antibody of claim 10 .