The combination of GlaxoSmithKline (NYSE:GSK) breast cancer drug Tykerb with a drug from rival Roche (OTC: RHHBY) works better compared to using either drug as a standalone therapy, according to a new study.

The findings could boost the treatment options for patients and the marketing potential for Tykerb, which falls well short of the Roche drug Herceptin in terms of global sales.

Just last September, GSK halted part of a phase 3 trial studying Tykerb after an independent committee concluded that Tykerb administered alone was unlikely to work better than Herceptin. But British pharma giant GSK, which maintains its U.S. headquarters in Research Triangle Park, opted to continue studying Tykerb, also called lapatinib, in some combination with Herceptin, known also as trastuzumab.

Dr. Jose Baselga, chief of oncology at Massachusetts General Hospital Cancer Center, led the study. Results of the GSK-funded study are published in the January 17 issue of The Lancet. Researchers said that the two drugs inhibit growth of human epidermal receptor 2, or HER2, a protein that promotes cancer cell growth. The Tykerb-Herceptin study enrolled 455 patients in 23 countries.

The patient group given a combination of Tykerb and Herceptin showed a 51.3 response rate.

By comparison, the group given Herceptin alone showed a 29.5 percent response rate; Tykerb alone produced a 24.7 percent response rate.

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