Tykerb, Avastin suffer disappointing data at SABCS

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GlaxoSmithKline ($GSK) has suffered a setback in its bid to broaden use of Tykerb to fight early breast cancer. The drug failed to reach its goal in a study testing it as an adjuvant treatment for HER2-positive breast cancer. It's not the first time Tykerb has flubbed an adjuvant study, either, Deutsche Bank analysts point out. They also predict "substantial use" of the drug in that setting "is very unlikely."

The company said Tykerb patients in the TEACH trial had a slightly improved rate of progression-free survival, the difference when compared with placebo wasn't statistically significant. "Although we are disappointed," GSK SVP Rafael Amado said, "[Tykerb] remains an important treatment option for patients with metastasis HER2-positive breast cancer." Amado added that other Tykerb trials, including adjuvant research, are ongoing.

There's one consolation, however: GSK isn't alone in reporting not-so-great data at the San Antonio Breast Cancer Symposium. A study of Avastin in HER2-positive breast cancer patients delivered just 3.2 months of additional progression-free survival and no overall survival benefit, The New York Times reports.

The numbers on Avastin's ability to stave off tumor growth in HER2 patients resemble those in two other studies presented to the FDA. Those trials involved patients whose cancers didn't test positive for HER2. That data was used by the agency as evidence in revoking Avastin's breast cancer approval.

Roche's Genentech unit tells the NYT it won't be asking the FDA to approve Avastin as a treatment specifically for HER2-positive breast cancer. "Our bottom line is we do not believe that the difference in P.F.S. is of a sufficient magnitude that it is likely to gain regulatory approval,'' Genentech's Sandra Horning told the paper.

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