[Efficacy and Safety of Pertuzumab for HER2-Positive Metastatic Breast Cancer].

The CLEOPATRA trial showed a significant improvement in the progression-free survival (PFS) and overall survival of patients with HER2-positive first-line metastatic breast cancer (MBC) who were treated with pertuzumab (PER), trastuzumab (TRA), and docetaxel (DTX), compared to those treated with placebo, TRA, and DTX. PER was approved in 2013 for treating HER2-positive MBC in Japan. Herein, we present the retrospective review of data from 10 HER2-positive MBC patients who received PER in our hospital between September 2013 and August 2014.T he median age was 52 years (range, 45-66 years), and 7 patients were positive for ER.Six patients had not received any previous chemotherapy for their metastatic disease, while the others had received comparatively heavy pretreatment doses of chemotherapy.Our patients received the PER, TRA, and DTX regimen, although 2 patients were treated without DTX. Four patients experienced a partial response, 6 patients experienced stable disease (SD), and 3 patients experienced SD for ≥6 months. The response rate was 40%, and the clinical benefit rate was 70%.The median PFS was 7.3 months (range, 2.5-11.5 months). Grade 3 neutropenia and allergic reactions were observed in 1 and 2 patients, respectively; no Grade 4 adverse events were observed, and thus, the regimen was well tolerated. Further clinical research seems to be warranted for developing new treatment strategies involving PER for HER2-positive MBC.