Phase II Study of Paclitaxel Given Once per Week Along With Trastuzumab and Pertuzumab in Patients With Human Epidermal Growth Factor Receptor 2–Positive Metastatic Breast Cancer

Purpose The CLEOPATRA (Clinical Evaluation of Trastuzumab and Pertuzumab) study demonstrated superior progression-free survival (PFS) and overall survival when pertuzumab was added to trastuzumab and docetaxel. Paclitaxel given once per week is effective and less toxic than docetaxel. We performed a phase II study to evaluate the efficacy and safety of pertuzumab and trastuzumab with paclitaxel given once per week. Patients and Methods Patients with metastatic human epidermal growth factor receptor 2–positive breast cancer with zero to one prior therapy were enrolled. Treatment consisted of paclitaxel 80 mg/m2 once per week plus trastuzumab (8 mg/kg loading dose → 6 mg/kg) once every 3 weeks plus pertuzumab (840 mg loading dose → 420 mg) once every 3 weeks, all given intravenously. The primary end point was 6-month PFS assessed by Kaplan-Meier methods. Results From January 2011 to December 2013, we enrolled 69 patients: 51 (74%) and 18 (26%) treated in first- and second-line metastatic settings, respectiv...