Table 3.

Combination strategies for prostate cancer

Combination	Rationale	Clinical trials
Radiation + vaccine or checkpoint inhibitor	Cells death => antigen release. Increased inflammation and secretion of immunomodulatory cytokines.	Radium-223 + sipuleucel-T Radium-223 + pembrolizumab Radium-223 + atezolizumab
Chemotherapy + vaccine or checkpoint inhibitor	Reduced tumor burden. Increased Fas expression. Antigen cascade.	Docetaxel + PROSTVAC Docetaxel + DCVAC/PCa Docetaxel + pembrolizumab
Hormone therapy (antiandrogens) + cancer vaccine or checkpoint inhibitor	Reduced tumor burden. Increased production of naive T cells and CD4+ effector T cells. Increased PD-L1 expression (enzalutamide).	Enzalutamide + PROSTVAC Enzalutamide + pembrolizumab
Checkpoint inhibitor + cancer vaccine or another checkpoint inhibitor	Activation of different T-cell population. Increased inflammation.	Listeria-based vaccine + pembrolizumab
PARP inhibitor + checkpoint inhibitor	DNA damage => antigen release. Increased inflammation.	Olaparib + pembrolizumab Olaparib + durvalumab