FDA grants AstraZeneca patent extension for Arimidex

WASHINGTON AstraZeneca said the Food and Drug Administration has granted it another six months of patent protection for its breast cancer drug Arimidex.

The patent extension through June 2010 was granted under pediatric exclusivity rules because the company conducted trials to investigate the drug’s potential for pediatric conditions with symptoms due to increased estrogen production. The company received the extension even though the drug did not pan out for these conditions, and the company will not be seeking a new licensed indication for them.

Arimidex (anastrozole) has been approved for use for three different medical conditions. In 1995, it was approved for the treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy. The drug was later approved, according to the FDA, for use in the "first-line treatment of postmenopausal women with hormone receptor positive or hormone receptor unknown locally advanced or metastatic breast cancer," and the "adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer" (in 2000 and 2002, respectively).

In the U.S., Arimidex sales reached $507 million for the first nine months of 2007. Arimidex has a market-leading 38.3 percent share of total prescriptions for hormonal treatments for breast cancer. Sales for the nine months were up 15 percent, with total prescriptions 6 percent higher than last year.