Phase II study of S-1 in combination with trastuzumab for HER2-positive metastatic breast cancer.

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  • 1 July 2014
    • journal article
Abstract
We undertook a prospective phase II study to evaluate the efficacy of S-1 plus trastuzumab combination regimen for human epidermal-growth factor receptor-2 (HER2)-positive metastatic breast cancer (MBC). HER2-positive MBC patients received oral administration of S-1 (80 mg/m2/day, days 1 to 28, every 6 weeks) and intravenous weekly trastuzumab (2 mg/kg), according to the results of a prior Phase I trial of our group. A total of 28 patients were enrolled and received a median of 3.5 (range 1-10) cycles of treatment. Overall response rate and clinical benefit rate were 53.6% and 75.0%, respectively. Progression-free survival was 30 weeks. With regard to grade 3 and 4 adverse effects, leucopenia, neutropenia, increase in serum alanine aminotransferase, and diarrhea were observed. Combination of S-1 and trastuzumab was tolerable and had excellent efficacy with good response and disease control in this trial.