REGN15505 + REGN4336

REGN15505 + REGN4336 is a combination immunotherapy being developed by Regeneron Pharmaceuticals for the treatment of metastatic castration-resistant prostate cancer (mCRPC) and clear cell renal cell carcinoma (ccRCC). This combination therapy utilizes two distinct bispecific antibodies to optimize T-cell responses against tumor cells. REGN15505 is a bispecific antibody targeting Prostate-Specific Membrane Antigen (PSMA) and 4-1BB (CD137), designed to provide localized costimulation to T cells within the tumor microenvironment. REGN4336 is a bispecific antibody targeting PSMA and CD3, which acts as a T-cell engager by bridging T cells to PSMA-expressing cancer cells to induce direct cytotoxicity. By combining these two agents, the treatment aims to provide both the primary activation signal (via CD3) and a potent costimulatory signal (via 4-1BB) specifically at the site of PSMA-expressing tumors, potentially overcoming the immunosuppressive environment of advanced prostate and renal cancers.