Method for reducing side effects of immune checkpoint control agent

1. A method for reducing one or more potentially lethal, anaphylactic side effects of an immune checkpoint regulator, said method comprising:

administering to a cancer patient in need of reducing one or more potentially lethal, anaphylactic side effects of the immune checkpoint regulator, in combination with the immune checkpoint regulator, an effective amount of an anti-CD4 antibody or antigen-binding fragment to deplete CD4-positive immune cells, said antibody or fragment being selected from:

1) an anti-CD4 antibody having an ADCC activity higher than the ADCC activity of the known anti-CD4 antibodies 6G5 and CE9.1 and/or a CDC activity that is higher than the CDC activity of the known anti-CD4 antibody OKT4, or

2) an anti-CD4 antibody or antigen-binding fragment thereof which antibody or fragment comprises a cytotoxic component bound thereto,

wherein said 1) anti-CD4 antibody and said 2) anti-CD4 antibody or antigen-binding fragment thereof is a human-type chimeric antibody, humanized antibody, or human antibody against human CD4;

wherein said immune checkpoint regulator is at least one antagonist against an inhibitory immune checkpoint molecule selected from PD-L1, CTLA-4, BTLA, LAG-3, TIM-3, and PD-1;

wherein said cancer is selected from cancers other than melanoma;

wherein in said method, first administration of the anti-CD4 antibody or the antigen-binding fragment is not carried out before first administration of the immune checkpoint regulator, and is carried out before second administration of the immune checkpoint regulator; and

wherein the effective amount of the anti-CD4 antibody or antigen-binding fragment is sufficient to reduce one or more potentially lethal, anaphylactic side effects of the immune checkpoint regulator.

2. The method according to claim 1 , wherein said inhibitory immune checkpoint molecule is at least one selected from the group consisting of CTLA-4, PD-L1, BTLA, LAG-3 and TIM-3.

3. The method according to claim 1 , wherein said immune checkpoint regulator is an antibody against an inhibitory immune checkpoint molecule.

4. The method according to claim 3 , wherein said antibody against an inhibitory immune checkpoint molecule is at least one selected from an anti-PD-L1 antibody, and antagonistic anti-CTLA-4 antibody.

5. The method according to claim 3 , wherein said antibody against an inhibitory immune checkpoint molecule is at least one selected from an antagonistic anti-BTLA antibody, antagonistic anti-LAG-3 antibody, and an antagonistic anti-TIM-3 antibody.

6. The method according to claim 1 , which comprises administering an effective amount of an anti-CD4 antibody having an ADCC activity higher than the ADCC activity of the known anti-CD4 antibodies 6G5 and CE9.1 and/or a CDC activity that is higher than the CDC activity of the known anti-CD4 antibody OKT4.

7. A method for cancer therapy by combination therapy with depletion of CD4-positive immune cells and one or more immune checkpoint regulators, said method comprising:

administering in combination with said one or more immune checkpoint regulators to a cancer patient in need thereof an effective amount of an anti-CD4 antibody or antigen-binding fragment to deplete CD4-positive immune cells, said antibody or fragment being selected from:

1) an anti-CD4 antibody having an ADCC activity higher than the ADCC activity of the known anti-CD4 antibodies 6G5 and CE9.1 and/or a CDC activity that is higher than CDC activity of the known anti-CD4 antibody OKT4, or

2) an anti-CD4 antibody or antigen-binding fragment thereof which antibody or fragment comprises a cytotoxic component bound thereto,

wherein said 1) anti-CD4 antibody and said 2) anti-CD4 antibody or antigen binding fragment thereof are a human-type chimeric antibody, humanized antibody, or human antibody against human CD4;

wherein said immune checkpoint regulator is at least one antagonist against inhibitory immune checkpoint molecule selected from PD-L1, CTLA-4, BTLA, LAG-3, TIM-3, and PD-1;

wherein said cancer is selected from cancers other than melanoma;

wherein in said combination therapy, first administration of the anti-CD4 antibody or the antigen-binding fragment is not carried out before first administration of the immune checkpoint regulator, and is carried out before second administration of the immune checkpoint regulator; and

wherein the effective amount of the anti-CD4 antibody or antigen-binding fragment is sufficient to reduce a potentially lethal, anaphylactic side effect of the one or more immune checkpoint regulators, thereby improving survival rate of the cancer patient.

8. The method according to claim 7 , which comprises administering an effective amount of 1) an anti-CD4 antibody having an ADCC activity higher than the ADCC activity of the known anti-CD4 antibodies 6G5 and CE9.1 and/or a CDC activity that is higher than the CDC activity of the known anti-CD4 antibody OKT4.

9. The method according to claim 7 , wherein said antibody 1) is an anti-CD4 antibody which contains no core fucoses in sugar chains present in its Fc region.

10. The method according to claim 1 , wherein said antibody 1) is an anti-human CD4 humanized antibody IT1208.

11. The method according to claim 7 , wherein said antibody 1) is an anti-human CD4 humanized antibody IT1208.

12. The method according to claim 7 , wherein said inhibitory immune checkpoint molecule is at least one selected from the group consisting of PD-L1, CTLA-4, BTLA, LAG-3 and TIM-3.

13. The method according to claim 12 , wherein said inhibitory immune checkpoint molecule is selected from PD-L1, CTLA-4, LAG-3, and PD-1.

14. The method according to claim 1 , wherein the cancer is selected from renal cancer, breast cancer, lung cancer, and gastric cancer.

15. The method according to claim 7 , wherein the cancer is selected from renal cancer, breast cancer, lung cancer, and gastric cancer.