Praecis Pharmaceuticals Inc. and Amgen Inc. haven't disclosed the reasons for the non-approvable letter they received from the FDA last week for Plenaxis abarelix, an LHRH/GnRH antagonist in development to treat prostate cancer. While the FDA's thinking isn't known, the agency does have a stated preference for data demonstrating survival and clinical benefit in cancer trials, which may not yet be addressed by the Plenaxis data.

Hormone deprivation therapy, including the use of androgen (testosterone) blockers and the LHRH agonists Lupron leuprolide from Tap Pharmaceuticals Inc. (Lake Forest, Ill.) and Zoladex goserelin from AstraZeneca plc (AZN, London, U.K.), is used in patients with metastatic prostate cancer.