ROCKVILLE, MarylandTykerb (lapatinib, GlaxoSmithKline) has received US Food and Drug Administration approval in combination with Xeloda (capecitabine, Roche) for the treatment of locally advanced or metastatic breast cancer in patients whose tumors over-express the HER2 receptor and who have previously received other cancer drugs, including an anthracycline, a taxane, and trastuzumab (Herceptin). Tykerb is the first targeted, once-a-day oral treatment authorized for this indication.
FDA approved the drug after a priority review of a randomized, phase III trial, which demonstrated that patients treated with Tykerb and Xeloda had a significant improvement in time to progression (TTP) and a higher response rate than patients who received Xeloda alone.
"Tykerb is a significant breakthrough for women with advanced HER-positive breast cancer," said Paolo Paoletti, MD, senior vice president of the company's Oncology Medicine Development Center. The approval reflects more than 16 years of research by the company, including more than 60 clinical trials and investigator-initiated collaborative research studies. "We are dedicated to the further study and development of Tykerb in a variety of settings, including adjuvant breast cancer as well as in other solid tumor types," Dr. Paoletti said.
Tykerb, a new molecular entity, enters the cell and uses discrete, multiple pathways to target the tyrosine kinase components of the EGRF and HER2 receptors on cells (see Figure). Over-expression of the receptors is associated with cell proliferation and other processes related to tumor progression, invasion, and metastases, and often indicates a poor prognosis and reduced overall survival.
The international, multicenter pivotal trial submitted by GlaxoSmithKline enrolled 399 HER2-positive, previously treated women with locally advanced or metastatic breast cancer. The combination drug group (n = 198) received five 250 mg Tykerb tablets at one time on each day of a 21-day cycle, as well as Xeloda 1,000 mg/m2 bid on days 1 through 14 of each cycle. The Xeloda-only arm (n = 201) received a dose of 1,250 mg/m2 bid for the first 2 weeks of the 3-week cycle.
At the recommendation of the trial's Independent Data Monitoring Committee, GlaxoSmithKline halted enrollment early in 2006 after a preplanned interim analysis of 321 patients showed the combined treatment group had a superior TTP, compared with the Xeloda-only arm. This statistically significant result exceeded the primary endpoint.