Lapatinib lands leading role in trastuzumab-resistant breast cancer

Combining lapatinib [Tykerb] with capecitabine [Xeloda] significantly delays the time to disease progression in women with trastuzumab [Herceptin]-resistant breast cancer, according to late-breaking data presented at the 42^nd annual meeting of the American Society of Clinical Oncology (ASCO) [Atlanta, Georgia, US; June 2006]. An interim analysis of a pivotal phase III study showed significant benefits for the novel combination in women with advanced or metastatic HER2 positive breast cancer whose disease had progressed despite treatment with trastuzumab; lapatinib plus capecitabine nearly doubled the time to disease progression, compared with capecitabine alone. Notably, no patients treated with lapatinib developed symptoms of congestive heart failure; declines in left ventricular ejection fraction were infrequent, asymptomatic, and reversible. Results of this study were so compelling that researchers terminated the trial early. Furthermore, data from this trial, and a second phase II study of lapatinib in HER2 metastatic breast cancer, demonstrated that in contrast to trastuzumab, lapatinib can penetrate the CNS, indicating that the novel compound may be effective for the treatment of brain metastases in such patients.