Multicenter phase 3 trial of adding metronomic capecitabine to aromatase inhibitor as initial therapy for HR-positive, HER2-negative metastatic breast cancer

The phase 3 MECCA trial, at 12 centers in China, evaluated addition of metronomic capecitabine to aromatase inhibitor (AI) as initial therapy for women with HR-positive, HER2-negative metastatic breast cancer (HR+ HER2- mBC). The full analysis set consisted of 126 patients in the metronomic capecitabine plus AI group and 128 patients in the AI-alone group. At median 50.7 months follow-up, 257 PFS events had occurred. The median PFS was 20.9 months in the combination group versus 11.9 months in the AI-alone group (HR 0.58; 95% CI 0.43-0.76) and the median OS was not reached versus 45.1 months (0.58; 0.37-0.93). The most common adverse events were palmar-plantar erythrodysesthesia and peripheral neuropathy; grade 3 events occurred in 15.1% of patients receiving the combination treatment. The authors conclude that addition of metronomic capecitabine to first-line AI resulted in significant improvement in PFS and OS among women with HR+ HER2- mBC.