Breast Cancer Drug Takes Big Step Toward First Place
FDA Advisers Back Femara as Drug Treatment of Choice
By Ori Twersky
Reviewed by Dr. Gary D. Vogin
Dec. 13, 2000 (Washington) -- Patients with advanced breast cancer may receive a different drug if the FDA follows the advice of its advisory committee. The panel of expert advisers voted Wednesday to endorse the approval of Femara as a therapy of first choice. The FDA isn't obligated to follow the advice of its expert panel, but the agency usually does so.
Femara, made by Novartis Pharmaceuticals Corporation, is in a class of drugs called aromatase inhibitors. Aromatase is a protein that converts male-type hormones into the common female hormone estrogen.
Why is this important? An estimated 70% of women with advanced breast cancer have what doctors call estrogen-dependent tumors. This means estrogen acts as fuel for the tumors. So if estrogen can be blocked, the hope is that the tumors may stop growing.
Most of the estrogen in young women is made in the ovaries. In postmenopausal women, however, most of the estrogen comes from the conversion of male-type hormones -- collectively known as androgens -- into estrogen. The conversion is carried out by aromatase, which is blocked by drugs like Femara.
The current standard drug for breast cancer is tamoxifen. Tamoxifen blocks the effects of estrogen in a different way. Overall, Femara was well tolerated, with similar side effects as tamoxifen. The most common of these is a tendency toward forming blood clots. In the study, Femara had fewer of these problems than tamoxifen.
In 1997, Femara was approved as a treatment to be used if tamoxifen failed. But if the panel's recommendations are followed, Femara could take the lead as the preferred first treatment.
The panel's recommendation was based upon a pivotal study of more than 900 women. That study demonstrated that Femara was more effective than tamoxifen in preventing the progression of advanced breast cancer in postmenopausal women. It took almost 10 months for the tumors to begin to grow again with Femara, as compared with about six months for those on tamoxifen. And overall, more patients responded to Femara as opposed to tamoxifen.
All told, this is good evidence that this drug performs as well -- if not better -- than tamoxifen.
If the FDA should follow its panel's recommendation, then Femara will become the second aromatase inhibitor to be approved as a first-line therapy after Arimidex, made by AstraZeneca.
Bolstering the FDA reviewer's position was a presentation by Harold Harvey, MD, who is a professor of medicine at Penn State College of Medicine in Hershey, Pa. He remarked that breast cancer that has spread cannot be cured, and therefore, a more important consideration should be quality of life.
The panel unanimously agreed. "I think this trial is adequate," says panel member George Sledge, MD, on behalf of the other committee members. Sledge is professor of medicine at Indiana University School of Medicine in Indianapolis. "[Femara] is a pleasure to use," he says.