The FDA ( Food and Drug Administration ) has approved Tykerb ( Lapatinib ), a new targeted anti-cancer treatment, to be used in combination with Capectabine ( Xeloda ), another cancer drug, for patients with advanced, metastatic breast cancer that is HER2 positive.
The combination treatment is indicated for women who have received prior therapy with other cancer drugs, including an anthracycline, a taxane, and Trastuzumab ( Herceptin ).
According to the American Cancer Society, about 180,000 new cases of breast cancer are diagnosed each year. Approximately 8,000 to 10,000 women die from metastatic HER2 positive breast cancer each year.
Tykerb is a kinase inhibitor working through multiple pathways to deprive tumor cells of signals needed to grow. Unlike, for example, Trastuzumab — a monoclonal antibody, which is a large protein molecule that targets the part of the HER2 protein on the outside of the cell — Tykerb is a small molecule that enters the cell and blocks the function of this and other proteins. Because of this difference in mechanism of action, Tykerb works in some HER2 positive breast cancers that have been treated with Trastuzumab and are no longer benefiting.
The approval of Tykerb was based on a randomized clinical trial in about 400 women with advanced or metastatic breast cancer that was also HER2 positive. In the trial, half the patients received Tykerb with Capecitabine and half received Capecitabine alone. Compared to patients receiving Capecitabine alone, the group of patients receiving Tykerb with Capecitabine had a statistically significant improvement in the time to tumor progression. In addition, the tumor response rate was higher in the group of patients receiving Tykerb with Capecitabine ( 24 percent vs. 14 percent ).
The most commonly reported Tykerb-related side effects included diarrhea, nausea, vomiting, rash and hand-foot syndrome which may include numbness, tingling, redness, swelling and discomfort of hands and feet.
Generally reversible decreases in heart function ( that can lead to shortness of breath ) have also been reported in a small percentage of patients.
Tykerb is available in tablets of 250 mg. An undivided dose of 1,250 mg should be taken orally once daily for 21 days and in combination with Capecitabine on days 1-14 of a 21 day cycle.
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