Generic Versions of Anastrozole Now Available in US

Zosia Chustecka

June 30, 2010

June 30, 2010 ( UPDATED July 2, 2010 ) — Generic versions of the aromatase inhibitor anastrozole have been approved in the United States, now that the branded product, Arimidex (AstraZeneca), has come off patent.

Arimidex had annual sales of $917 million in the United States, according to IMS data.

The US Food and Drug Administration (FDA) approved 11 generic versions of anastrozole on June 28 from the following companies: Accord Healthcare Inc, Dr. Reddy's Laboratories Ltd, Natco Pharma Ltd, Roxane Laboratories Inc, Sandoz Inc, Stason Pharmaceuticals Inc, Synthon Pharmaceuticals Inc, TEVA Pharmaceuticals USA, Three Rivers Pharmaceuticals LLC, Watson Laboratories Inc, and Zydus Pharmaceuticals USA Inc.

Aromatase inhibitors are used in the treatment of hormone-receptive breast cancer after surgery to reduce the risk for recurrence. They are usually prescribed for a period of 5 years.

Having generic versions of the drugs available will reduce the cost of therapy.

Aromatase inhibitors (before going off patent) cost around $2300 per year, according to a study published online June 28 in the Journal of Clinical Oncology (by Hershman et al). The alternative therapy in these patients is tamoxifen, which is available generically and costs around $1200 per year.

This is the first time that generic versions of an aromatase inhibitors have been made available in the United States. There had been an FDA approval in December 2008 of a generic version of letrozole, from Mylan Pharmaceuticals, but subsequent litigation by the manufacturer (Novartis) established that the patent protection in the United States for the branded product Femara will not expire until 2011, so there is no generic product currently available.


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