The FDA has expanded the approved use of trastuzumab (Herceptin, Genen-tech), a biological cancer drug. In combination with other cancer drugs, tras-tuzumab is indicated for patients with HER2-positive breast cancer after surgery.
Herceptin is a targeted therapy against the HER2 protein on cancer cells. An excessive amount of HER2 protein causes cancer cells to grow more rapidly, and standard chemotherapy may be less effective. Approximately 25% of women with breast cancer have tumors that produce excessive HER2 protein.
In 1998, the drug was approved for the treatment of metastatic breast cancer. The new approval expands its use to women with cancer only in the breast or lymph nodes that has been surgically removed.
Studies conducted by the National Cancer Institute were ended early because of the positive results. Women who received trastuzumab combined with chemotherapy had fewer relapses for up to three years after surgery. The estimated three-year disease-free rates were 87% in patients receiving tras-tuzumab and chemotherapy and 75% in those patients receiving chemotherapy alone.
The most serious side effect was heart failure. Patients must be screened for heart function before and during therapy.