Breast cancer patients who have not responded well to standard treat-ment now have a new drug to fight their disease.
The Food and Drug Administration on Wednesday approved the marketing of Taxotere, a powerful chemotherapy for breast cancer patients whose disease has progressed despite treatment with doxorubicin, currently the standard first-line chemotherapy.Taxotere is in the same class of drugs as Taxol. Both act by disrupting the internal structure of forming cancer cells and are based on extracts from the yew tree. However, researchers said clinical trials have shown Taxotere is more active against breast cancers that resist other treatments.
"These are chemical first cousins, but they are really very different," said Dr. Howard Burris, a specialist with the Cancer Therapy and Research Center in San Antonio, where both Taxotere and Taxol are being tested.
He said the center's studies found that breast cancer responded to Taxol in about 29 percent of patients and to Taxotere in more than a 50 percent. The FDA said Taxotere shrank tumors in 42 percent of patients tested for an average of six months.
Taxotere will be distributed by Rhone-Poulenc Rorer of Collegeville, Pa. Taxol, marketed by Bristol-Myers Squibb, was approved for ovarian cancer in 1992 and for breast cancer in 1994.
Both Taxotere and Taxol cause serious side effects. Rhone-Poulenc Rorer reported to the FDA in October that in worldwide use, side effects killed 23 patients out of 1,070 treated.
Burris said both drugs cause hair loss and a decrease in white blood cells, the body's primary disease-fighting cells. He said the white blood cell loss is much steeper, however, with Taxotere.
Also, liver function can be affected seriously by Taxotere. An FDA advisory panel recommended in October that the drug not be used on patients with elevated liver enzymes.
The FDA approved Taxotere on an accelerated basis, a system that gives patients early access to drugs that show in clinical trials some important benefits, such as shrinking tumors.
Other considerations, such as survival time and quality of life, will be evaluated in clinical trials now under way. If post-marketing studies fail to verify the benefits seen in the early clinical trials, the FDA can withdraw the drug.
Taxotere is given intravenously, on an outpatient basis, every three weeks.