FP4643

FP4643 is a small molecule inhibitor of 17-beta-hydroxysteroid dehydrogenase type 1 (17β-HSD-1), an enzyme responsible for the conversion of the weak estrogen estrone (E1) into the potent estrogen 17-beta-estradiol (E2). Developed by Forendo Pharma (now part of Organon), FP4643 is designed to treat estrogen-dependent conditions by reducing local estradiol levels without affecting systemic estrogen concentrations. In preclinical models of endometrial cancer, FP4643 has demonstrated the ability to significantly inhibit tumor growth and reduce metastatic spread, suggesting its potential as a novel endocrine therapy for gynecological malignancies.