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Wednesday 12th October, 2005

The FDA has approved Pfizer's Aromasin for adjuvant treatment of early breast cancer in postmenopausal women.


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Gene affects tamoxifen's benefit for breast cancer

Pfizer Inc has received approval from the U.S. Food and Drug Administration (FDA) to market Aromasin? (exemestane tablets) for adjuvant treatment of postmenopausal women with estrogen-receptor positive early breast cancer following two-to-three years of tamoxifen for a completion of five consecutive years of adjuvant hormonal therapy.

The approval was based on the Intergroup Exemestane Study (IES) which showed that patients who switched to Aromasin after two-to-three years of tamoxifen, for a combined total of five years of therapy, had 31 percent more protection from cancer recurrence than those who remained on five years of tamoxifen therapy.

This landmark study, published in the New England Journal of Medicine, established the superiority of switching to Aromasin rather than remaining on tamoxifen. Following its publication, the American Society of Clinical Oncologists and the National Comprehensive Cancer Network updated their guidelines to support the use of a new switch regimen using Aromasin adjuvant treatment.

"Pfizer is pleased to announce this treatment advance," said Dr. Joseph Feczko, Pfizer's chief medical officer. "This new indication for Aromasin provides women with a new treatment regimen that can significantly improve their chances of remaining breast cancer-free."

The IES trial involved over 4,700 postmenopausal women with estrogen-receptor positive breast cancer who were followed for an average of 35 months. Patients receiving Aromasin experienced a significant reduction in the risk for recurrence of the disease, compared to those continuing on tamoxifen. This reduction includes fewer local and distant tumors as well as new cancers in the other breast.

"This new approval for Aromasin clearly provides physicians and patients a more effective way of protecting against cancer recurrence compared to the current treatment practice of five years of tamoxifen therapy," said Dr. Stephen Jones, medical director at U.S. Oncology Research in Houston, Texas.

The most common side effects for Aromasin, which were mild-to-moderate, include hot flashes (21.2%), fatigue (16.1%) and arthalgia/ bone pain (14.6%).

Aromasin should not be administered to pre-menopausal women and women who are pregnant. Dose modifications should be considered for patients taking concomitant CYP3A4 inducers.

Breast cancer is one of the most common cancers occurring in women and the second leading cause of death from cancer in women, after lung cancer. Adjuvant therapy is treatment given following surgical removal of a primary tumor (the first tumor that occurs before it spreads to other parts of the body).

Last month, Pfizer received approval for adjuvant treatment in the European Union. Aromasin was approved in the United States late in 1999 for the treatment of advanced breast cancer in postmenopausal women whose tumors have stopped responding to tamoxifen. It also is approved for use in Europe, Japan, and South America. Currently, Aromasin is available in more than 50 countries around the globe.

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