Endoxifen, an Estrogen Receptor Targeted Therapy: from Bench to Bedside

Endocrinology. 2021 Sep 4:bqab191. doi: 10.1210/endocr/bqab191. Online ahead of print.ABSTRACTThe selective estrogen receptor modulator (SERM), tamoxifen, is the only endocrine agent with approvals for both the prevention and treatment of premenopausal and postmenopausal estrogen-receptor positive (ER+) breast cancer as well as for the treatment of male breast cancer. Endoxifen, a secondary metabolite resulting from CYP2D6-dependent biotransformation of the primary tamoxifen metabolite, N-desmethyltamoxifen (NDT), is a more potent antiestrogen than either NDT or the parent drug, tamoxifen. However, endoxifen's antitumor effects may be related to additional molecular mechanisms of action, apart from its effects on ER. In phase I/II clinical studies, the efficacy of Z-endoxifen, the active isomer of endoxifen, was evaluated in patients with endocrine-refractory metastatic breast cancer as well as in patients with gynecologic, desmoid and hormone-receptor positive solid tumors, and demonstrated substantial oral bioavailability and promising antitumor activity. Apart from its potent anticancer effects, Z-endoxifen, appears to result in similar or even greater bone agonistic effects while resulting in little or no endometrial proliferative effects compared to tamoxifen. In this review we summarize the preclinical and clinical studies evaluating endoxifen in the context of breast and other solid tumors, the potential benefits of endoxifen in bone, as well as its emerging role as an...
Source: Endocrinology - Category: Endocrinology Authors: Source Type: research