Multicenter Phase II Trial of Neoadjuvant Therapy With Trastuzumab, Docetaxel, and Carboplatin for Human Epidermal Growth Factor Receptor-2–Overexpressing Stage II or III Breast Cancer: Results of the GETN(A)-1 Trial

Abstract

Purpose Trastuzumab plus chemotherapy has become the standard of care for human epidermal growth factor receptor-2 (HER-2) –positive breast cancer. Trastuzumab-based preoperative systemic therapy (PST; neoadjuvant therapy) also appears promising, warranting further investigation. Patients and Methods Patients with HER-2-positive, stage II/III, noninflammatory, operable breast cancer requiring a mastectomy (but who wanted to conserve the breast) received trastuzumab 4 mg/kg (day 1), followed by 2 mg/kg weekly, plus docetaxel 75 mg/m2 every 3 weeks, and carboplatin (area under curve, 6) for six cycles before surgery. The primary end point was pathologic complete response (pCR) rate, determined from surgical specimens. Results Seventy patients were enrolled. Most patients had clinical T2/T3 tumors (100%) or clinical N1/2 nodes (53%). Sixty-seven patients (96%) completed six cycles of therapy, one patient withdrew due to progressive disease, and two patients withdrew for toxicity. A complete or partial objective clinical response occurred in 95% of patients (85% and 10%, respectively). Surgery was breast conservative in 45 (64%) of 70 patients. In an intent-to-treat analysis, tumor and nodal pCR were seen in 27 (39%) of 70 patients. Centralized retrospective analysis of HER-2 status demonstrated a 43% pCR rate in the 24 of 56 confirmed HER-2-overexpressing (3+) and/or fluorescence in situ hybridization–positive tumors. Treatment was generally well tolerated. Grade 3/4 neutropenia and febrile neutropenia were uncommon (2%). Two patients withdrew prematurely due to a transient, asymptomatic decrease in left ventricular ejection fraction. No symptomatic cardiac dysfunction occurred. Conclusion PST with trastuzumab plus docetaxel and carboplatin achieved promising efficacy, with a good pCR rate and favorable tolerability in stage II or III HER-2-positive breast cancer.