Lapatinib - Member of a New Generation of ErbB-Targeting Drugs.

SUMMARY: Women with advanced or metastatic ErbB2 (HER2)-positive breast cancer have limited therapeutic options once their disease has progressed on trastuzumab-based standard initial chemotherapy regimens. Therefore, there has been a clear need for alternative treatments in this advanced setting. The small molecule lapatinib is a dual receptor tyrosine kinase inhibitor of both ErbBl and ErbB2. In the pivotal phase III trial, lapatinib combined with capecitabine has demonstrated superior efficacy over capecitabine alone in this group of patients, with a median time to tumor progression of 8.4 months in the combination therapy group versus 4.4 months in the monotherapy arm. This improvement was achieved without an increase in serious toxic effects or symptomatic cardiac events. In addition, with the advent of Lapatinib, the empirically adopted practice of continuing trastuzumab beyond progression has to be seen in a different light. This is especially true since an exploratory analysis has suggested that the earlier use of the combination lapatinib plus capecitabine is associated with a benefit in time to progression and overall survival.