Efficacy of Lapatinib Plus Capecitabine After TDM-1 in HER2-Positive Metastatic Breast Cancer Patients.

Different targeted therapy options exist for treating HER2-positive metastatic breast cancer patients. This study evaluated the efficacy and tolerability of the lapatinib plus capecitabine combination after TDM-1 in HER2-positive metastatic breast cancer patients. We retrospectively evaluated the HER2-positive metastatic breast cancer patients' data. The patients who progressed after trastuzumab-based chemotherapy and TDM-1 were included in the study. We used the Kaplan-Meier for survival analysis. Eighteen patients were involved in the study. The average age was 48 (range 31-65). De novo metastatic patient's number was 5 (27.8%). The most common metastatic sites were liver (50%), lung (44.4%), and brain (44.4%), respectively. All patients were previously treated with trastuzumab + chemotherapy and TDM-1. Also, seven (38.9%) patients received hormonotherapy and twelve (66.7%) patients received palliative radiotherapy. The complete response ratio was 5.6%, partial response 11.8%, and stable response 29.4%. Median progression-free survival was found as 5.5 (95% CI, 3.2-7.7) months. The hematological and non-hematological toxicity ratio was 41.2% and 52.9%, respectively. Grade 3-4 toxicity (diarrhea, anemia, and mucositis) was observed in four (22.2%) patients. The median OS duration was 8.2 months (95% CI, 4.3-12.0). Treatment options are limited in heavily pretreated HER2-positive breast cancer patients. Despite a small number of patients, this study showed that the lapatinib plus capecitabine combination was effective and well-tolerated in heavily pretreated HER2-positive breast cancer patients after TDM-1.