Letoval

Letrozole is a selective, nonsteroidal aromatase inhibitor that blocks the conversion of androgens to estrogens by competitively binding to the aromatase enzyme, thereby profoundly suppressing circulating estrogen levels in postmenopausal women.[1][2] Developed and marketed as Femara by Novartis, it is administered orally in 2.5 mg tablets and serves as a cornerstone endocrine therapy for hormone receptor-positive breast cancer, where estrogen fuels tumor growth.[3][4]