RLA-5331

RLA-5331 is a research-stage ferrous iron-activatable drug conjugate (FeADC) designed for the treatment of metastatic castration-resistant prostate cancer (mCRPC). It consists of an antiandrogen payload linked to a trigger that is selectively cleaved by labile ferrous iron (Fe2+), which is found at elevated levels in the mCRPC tumor microenvironment. This mechanism allows for the targeted release of the antiandrogen within the tumor, potentially reducing systemic side effects and central nervous system (CNS) toxicities typically associated with second-generation androgen signaling inhibitors. Preclinical studies have shown that RLA-5331 is stable in vivo, effectively downregulates androgen-responsive genes like KLK-2 and KLK-3, and exhibits potent antiproliferative activity against various prostate cancer cell lines.