Neoadjuvant chemotherapy with trastuzumab, docetaxel, and carboplatin administered every 3 weeks for Japanese women with HER2-positive primary breast cancer: efficacy and safety.

Background: This phase II neoadjuvant study evaluated the efficacy and safety of a triweekly regimen of docetaxel and carboplatin in combination with trastuzumab (TCbH) in Japanese women with human epidermal growth factor receptor type2 (HER2)-positive primary breast cancer.

Methods: Patients with HER2-positive, stage I-III invasive breast cancer received six courses of trastuzumab (8 mg/kg loading dose, then 6 mg/kg, day 1), docetaxel (75 mg/m, day 1), and carboplatin (area under the curve: 6, day 1) every 3 weeks. The primary endpoint was pathological complete response (pCR) of both breast and axillary lymph node disease.

Results: Fifty patients were enrolled in this study. Median age was 58 (range 32-75) years. All patients underwent definitive surgery. Thirty-three (66%) patients completed the chemotherapy course, while the treatment was delayed or discontinued in the other 17 (34%) patients because of adverse events (AEs). The pCR rate was 52%; the overall response rate was 66%. Grade 3/4 AEs due to nonhematological toxicity were anorexia (4%), diarrhea (2%), and rash (2%), and those due to hematological toxicity were neutropenia (36%), anemia (12%), and thrombocytopenia (2%).

Conclusion: Although the triweekly six-course regimen of TCbH achieved a high pCR rate, hematological AEs frequently occurred during the latter part of the chemotherapy course. One-third of patients experienced delayed or discontinued chemotherapy. Clinical registration number: http://www.umin.org.au UMIN000013513.