As expected, the FDA has given its approval to Tykerb, GlaxoSmithKline's therapy for metastatic breast cancer in combination with Xeloda. Glaxo is betting that the oral formulation for Tykerb will beat out a competing injectable, helping it build sales among the 10,500 women in the U.S. and Europe who could benefit from the therapy. Tykerb is also in trials for metastatic brain cancer. One study indicated that Tykerb with Xeloda delayed tumor growth by more than eight months, twice as long as Xeloda alone, though a later trial reduced that advantage to seven months compared to five months. Advocacy groups say they're still waiting for survival data on the drug, which will be a better indicator of its real value to patients. It's not unusual for regulators to base a decision on a cancer therapy on progression data alone, though, as researchers gather survival data.