HDP-103

HDP-103 is an investigational antibody–drug conjugate from Heidelberg Pharma that applies the company’s Amanitin-based ATAC technology to target prostate-specific membrane antigen (PSMA) for the treatment of metastatic castration-resistant prostate cancer (mCRPC). It consists of a PSMA-directed monoclonal antibody site‑specifically conjugated to the amatoxin payload Amanitin, which inhibits RNA polymerase II, leading to transcriptional arrest and apoptosis, including in otherwise dormant tumor cells.[2][3][7] Preclinical in vitro and in vivo studies have demonstrated potent antitumor activity, a promising therapeutic window, and favorable pharmacokinetics, with particular sensitivity in 17p‑deleted prostate cancer cells where Amanitin susceptibility is enhanced.[2][7] HDP-103 has completed GMP manufacturing and extensive toxicology testing, is in late preclinical development with a planned regulatory trial application, and is partnered for regional development in Asia (excluding Japan) through a licensing agreement with Huadong.[2][5][9]