This summary table contains detailed information about research studies. Summary tables offer an informative look at the science behind many breast cancer guidelines and recommendations. However, they should be viewed with some caution. In order to read and interpret research tables successfully, it is important to understand some key concepts. Learn how to read a research table.
Introduction: The drug lapatinib (Tykerb) is a tyrosine-kinase inhibitor. This class of drugs targets enzymes important for cell functions (called tyrosine-kinase enzymes). Lapatinib is used to treat HER2/neu-positive metastatic breast cancer in women who have already had chemotherapy and trastuzumab (Herceptin).
Lapatinib combined with chemotherapy, hormone therapy or trastuzumab may increase progression-free survival (the length of time before the metastatic breast cancer spreads).
Side effects of lapatinib include diarrhea, nausea, vomiting, rash and fatigue. In rare cases, it has been linked to lung problems .
Learn more about lapatinib.
Study selection criteria: Phase III clinical trials with 100 or more participants with HER2/neu-positive metastatic breast cancer. For phase III clinical trials of chemotherapy, all participants had past treatment with chemotherapy and trastuzumab for metastatic breast cancer. For phase III clinical trials of hormone therapy, past treatment varied.
Study Population(number of participants)
Overall Response Rate—Percent who Responded to Treatment(95% CI)
Overall Survival at One Year
Phase III Clinical Trials-Chemotherapy
Guan et al. 
Chemotherapy alone (paclitaxel)
Geyer et al. 
Lapatinib with chemotherapy (capecitabine)
Chemotherapy alone (capecitabine)
Phase III Clinical Trials-Hormone Therapy
Schwartzberg et al. 
219 women with no prior treatment for metastatic breast cancer
Lapatinib with letrozole
Johnston et al. 
Phase III Clinical Trials-Trastuzumab
Blackwell et al. [6-7]
Lapatinib with trastuzumab
* Estimated overall survival at 15 months.
† Statistically significant difference between the two treatment groups.
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