엑스메스탄

개요Exemestane was launched in US and other countries for the treatment of estrogendependent tumors and postmenopausal breast cancer. It is a novel steroidal compound structurally related to the natural substrate for the biosynthesis of estrogen, androstanedione, and can be synthesized by methylidenation of androsta-1, 4-dien- 17beta-ol-3-one in 6 position then oxidation of the alcohol function. Exemestane is an irreversible inactivator of the aromatase enzyme system, so inducing in vivo a dose-related sustained suppression of serum estrogen and minimal endocrine activity. It is the first steroidal representative of the third-generation of orally active aromatase inhibitors with a highly potent and selective mechanism of action, displaying good tolerability and safety profile. In rats with DMBA-induced mammary tumors, 10 to 100 mglkg of exemestan administered po twice-daily for 4 weeks resulted in 76 to 88% regression. In women failing anti-estrogen therapy with tamoxifen, this agent has demonstrated high activity in locally advanced or metastatic disease. In addition, it may also have potential for breast cancer prevention.

용도Labeled Exemestane, intended for use as an internal standard for the quantification of Exemestane by GC- or LC-mass spectrometry.

일반 설명Exemestane, 6-methylenandrosta-1,4-diene-3,17-dione (Aromasin), is the first steroid-basedaromatase inhibitor approved for the treatment of breastcancer in the United States. It is a mechanism-based inactivatorthat irreversibly inhibits the enzyme. Plasma estrogenlevels are reduced by 85% to 95% within 2 to 3 days, and effectslast 4 to 5 days. Exemestane does not inhibit any of themajor cytochromes P450 and has essentially no interactionwith steroid receptors, with only a very weak affinity for theAR. The 17β-hydroxyexemestane reduction product, however,has much higher affinity for the AR than the parent(still several fold less than DHT, 0.28% for parent vs. 30%for metabolite). The clinical significance of the affinity islikely minimal because of the low levels of the metaboliteproduced.