endoxifen + goserelin

**Endoxifen + goserelin** is a pharmaceutical combination consisting of two distinct drugs: **endoxifen**, a potent active metabolite of tamoxifen that acts as an estrogen receptor modulator, and **goserelin**, a gonadotropin-releasing hormone (GnRH) agonist which leads to suppression of ovarian estrogen production. Endoxifen exerts its antitumor effects primarily by binding to estrogen receptors (acting as an antagonist in breast tissue), thereby inhibiting estrogen-stimulated growth of hormone receptor-positive breast cancer cells. Goserelin acts at the pituitary gland to downregulate LH and FSH production, resulting in medical ovarian suppression and markedly reduced circulating estrogen levels. The combined therapy is designed for enhanced estrogen deprivation in hormone-sensitive breast cancer, particularly in premenopausal women. Clinical evidence suggests that while both agents are effective individually for endocrine-responsive breast cancer, combining them does not provide additional efficacy over monotherapy, and may even increase risk in certain high-risk patient populations. Endoxifen offers some advantages over standard tamoxifen, including higher potency and fewer estrogenic side effects.