ArticleDevelopment of Aromatase Inhibitors and Their Pharmacologic ProfileLønning, Per Eystein, M.D., Ph.D.; Geisler, Jürgen, M.D., Ph.D.; Bhatnager, Ajay, Ph.D.Author Information From the Haukeland Hospital, Section of Oncology, Department of Medicine, University of Bergen, Bergen, Norway (P.E.L. and J.G.), and Novartis Pharma AG, Basel, Switzerland (A.B.). Address correspondence and reprint requests to Dr. Per E. Lønning, Haukeland University Hospital, Section of Oncology, Department of Medicine, University of Bergen, Bergen, Norway 5021. American Journal of Clinical Oncology: August 2003 - Volume 26 - Issue 4 - p S3-S8 Buy Abstract Major advances have been recently made in the treatment of postmenopausal women with hormone-sensitive breast cancer. It is widely accepted that estrogen is associated with the progression of hormone-sensitive breast cancer. Whereas previous therapy was based on surgical ablation (ovariectomy, adrenalectomy, and hypophysectomy) or additive treatment (estrogens, androgens), more recently antiestrogens (in premenopausal as well as postmenopausal women), medical ovarian ablation, and aromatase inhibition have replaced these procedures. The current focus of clinical research efforts is to maximize efficacy with these agents and determine an effective treatment strategy for these patients. This article reviews the development of aromatase inhibitors and inactivators (AIs), with particular emphasis on the potent third-generation agents now available. Also provided is information on the relative potency and efficiency of estrogen synthesis inhibition with these agents. Results from in vitro and in vivo studies of AIs suggest that there is variability in efficacy among agents in this class, and the potential clinical implications of these variations are discussed. © 2003 Lippincott Williams & Wilkins, Inc.