GlaxoSmithKline has suffered a setback with the news that Tykerb has failed a late-stage study investigating whether adjuvant treatment with the drug will improve disease-free survival in women with early-stage HER2 positive breast cancer.

Results have been presented at the San Antonio Breast Cancer Symposium from TEACH, a Phase III trial designed to evaluate the effects of Tykerb/Tyverb (lapatinib) monotherapy when given to women who were diagnosed with HER2 positive breast cancer, had received treatment, but not Roche's rival drug Herceptin (trastuzumab), and remained disease free. The primary objective of the study, which involved over 3,000 women, was to compare DFS between women receiving lapatinib and those receiving placebo.  

After a median follow-up of four years, DFS events occurred in 13% of patients in the lapatinib arm and 17% on placebo. Rafael Amado, head of oncology at GSK, said that "although we are disappointed that the improvement in DFS with lapatinib monotherapy in TEACH did not reach statistical significance", combination therapy with Tykerb "remains an important treatment option for patients with metastatic Her2+ breast cancer whose disease has progressed on treatment with trastuzumab-based regimens”.

He added that "we look forward to the results from ongoing clinical trials with lapatinib in different combinations and lines of therapy, including the adjuvant setting". Tykerb was first approved for use in combination therapy in the metastatic setting in 2007 and is currently available in 107 countries; nine-month sales were up 3% to £172 million.