FibroGen, Inc. announced that clinical data from the dose escalation portion of the Phase 1b/2 study of FG-3246 in combination with enzalutamide in patients with metastatic castration resistant prostate cancer have been selected for a poster presentation at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting taking place May 31-June 4, 2024 in Chicago, Illinois. FG-3246 (also known as FOR46) is a potential first-in-class fully human antibody-drug conjugate (ADC), exclusively in-licensed from Fortis Therapeutics, and is being developed by FibroGen for metastatic castration-resistant prostate cancer and other tumor types. FG-3246 binds to a tumor-specific epitope of CD46, a cell receptor target, that induces internalization upon antibody binding, is present at high levels in prostate cancer and other tumor types, and demonstrates limited expression in most normal tissues.

FG-3246 is comprised of an anti-CD46 antibody, YS5, linked to the anti-mitotic agent, MMAE, which is a clinically and commercially validated ADC payload. FG-3246 has demonstrated anti-tumor activity in both preclinical and clinical studies. FG-3246 is currently in an ongoing investigator-initiated Phase 1b/2 study being conducted at UCSF to evaluate it in combination with enzalutamide with initial data expected in mid-2024, and a biomarker trial using a PET biomarker for CD46 using the same antibody backbone.

The company anticipates the initiation of a Phase 2 monotherapy dose optimization study of FG-3246 in metastatic castration-resistant prostate cancer in 2H 2024. FG-3246 is an investigational drug and not approved for marketing by any regulatory authority.