Exemestane Case Study

By Jeff McGilvra, Ph.D.

Big Pharma’s patent cliff coupled with a push by legislators around the world to control healthcare costs have helped contribute to a booming generic pharmaceuticals industry. As blockbuster drugs such as LIPOITOR®, Lexapro®, and Plavix® come of patent, generic drug makers are rushing to develop generic equivalents, and using contract manufacturing organizations to manufacture the active pharmaceutical ingredients (APIs). While many APIs requiring straightforward synthesis have been outsourced to lowcost locations, APIs requiring complex chemistries and regulatory approval procedures have been more efficiently manufactured in the United States and Europe. These APIs, which include vitamin D analogs, prostaglandins, and steroids, often require completion of substantial development work prior to establishing industrially viable manufacturing processes. An efficient preparation of one such API, exemestane, was developed by scientists at Cedarburg Hauser Pharmaceuticals. The development program ultimately culminated in a process patent as well as the submission of a Drug Master File to the FDA.

Exemestane Overview
Exemestane, chemically identified as 6-methylideneandrosta-1,4-diene-3,17-dione, is the generic equivalent to Pfizer’s AROMASIN®. Clinically, exemestane is approved for use as a steroidal aromatase inhibitor for the treatment of estrogen-dependent breast cancer in post-menopausal women. Additional clinical results published by Gross et al. in 2011 suggest that exemestane may also find use as a breast cancer preventive medication in post-menopausal women, though this use has yet to receive FDA approval.