Mechanism of Action
The growth of some cancers of the breast is stimulated or maintained by estrogens. Treatment of breast cancer thought to be hormonally responsive (i.e., estrogen and/or progesterone receptor positive or receptor unknown) has included a variety of efforts to decrease estrogen levels (ovariectomy, adrenalectomy, hypophysectomy) or inhibit estrogen effects (antiestrogens and progestational agents). These interventions lead to decreased tumor mass or delayed progression of tumor growth in some women. In postmenopausal women, estrogens are mainly derived from the action of the aromatase enzyme, which converts adrenal androgens (primarily androstenedione and testosterone) to estrone and estradiol. The suppression of estrogen biosynthesis in peripheral tissues and in the cancer tissue itself can therefore be achieved by specifically inhibiting the aromatase enzyme. Letrozole is a nonsteroidal competitive inhibitor of the aromatase enzyme system; it inhibits the conversion of androgens to estrogens. In adult nontumor- and tumor-bearing female animals, letrozole is as effective as ovariectomy in reducing uterine weight, elevating serum LH, and causing the regression of estrogen-dependent tumors. In contrast to ovariectomy, treatment with letrozole does not lead to an increase in serum FSH. Letrozole selectively inhibits gonadal steroidogenesis but has no significant effect on adrenal mineralocorticoid or glucocorticoid synthesis. Letrozole inhibits the aromatase enzyme by competitively binding to the heme of the cytochrome P450 subunit of the enzyme, resulting in a reduction of estrogen biosynthesis in all tissues. Treatment of women with letrozole significantly lowers serum estrone, estradiol and estrone sulfate and has not been shown to significantly affect adrenal corticosteroid synthesis, aldosterone synthesis, or synthesis of thyroid hormones.
Dr. Reddy's Expertise
Headquartered in Hyderabad, India, Dr. Reddy's Laboratories is one of the leading Active Pharmaceutical Ingredients (API) suppliers globally. Dr. Reddy's API business is a preferred partner to pharma companies across the US, Europe, Brazil, Latin America, Japan, China, Korea, Middle East and other emerging markets.
Dr. Reddy's API business thrives on the deep technical strengths established over the last 30+ years in the development and manufacture of complex APIs such as steroids, peptides, complex long chain molecules and highly potent APIs (HPAPIs / oncology drugs). This expertise is complemented by our prowess in intellectual property and regulatory affairs which helps us consistently meet and exceed regulatory standards. Dr. Reddy's Letrozole API is the outcome of the extensive expertise in R&D, IP, and Regulatory.
A key component in helping our customers be first to market is a responsive supply chain. We achieve this by making sure that all our facilities are operating efficiently and to the latest standards of quality, safety, and productivity. A strong interconnect between business and factories allows for a quick reaction to dynamic market changes, so that we can avert shortages and meet sudden surges in demand.
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All product information, including that with regard to active pharmaceutical ingredients (API), the indication, and possible mechanism(s) of action, is based on publicly available product label.