z-endoxifen

Z-endoxifen is the (Z) isomer of endoxifen, a nonsteroidal selective estrogen receptor modulator (SERM) and an active metabolite of tamoxifen. It acts primarily by antagonizing the estrogen receptor in breast tissue and also inhibits protein kinase C beta 1 (PKCβ1), which may contribute to its antitumor effects. Unlike tamoxifen, Z-endoxifen does not require metabolic activation by CYP2D6 and achieves higher plasma concentrations when administered directly. It is being developed as an oral therapy for estrogen receptor-positive (ER+) breast cancer—including cases resistant to prior endocrine therapies—and has shown activity in other solid tumors such as desmoid tumors. Additionally, it has been investigated for acute manic episodes in bipolar I disorder due to its PKC inhibition. Atossa Therapeutics is developing a proprietary oral formulation designed to bypass stomach acid and maximize bioavailability[1][3][4][5][6][7].

Brand names

Zonalta

Other names

(Z)-endoxifenendoxifen4-hydroxy-N-desmethyltamoxifendesmethylhydroxytamoxifen