HER2-Positive Metastatic Breast Cancer Patients Receiving Pertuzumab in a Community Oncology Practice Setting: Treatment Patterns and Outcomes.

BACKGROUND: Pertuzumab (Perjeta®), a HER2/neu receptor antagonist, was approved by the US Food and Drug Administration in June 2012 for use in the first-line setting for patients with HER2-positive metastatic breast cancer (mBC). OBJECTIVE: This retrospective study investigated the clinical and demographic characteristics, treatment patterns, safety, and clinical outcomes for patients with HER2-positive mBC who received pertuzumab in the first-line setting in US community oncology practices. METHODS: Patients with HER2-positive mBC, who initiated pertuzumab within 60 days of mBC diagnosis between June 2012 and June 2014, followed through December 2014, had ≥2 visits within the McKesson Specialty Health/US Oncology Network, and were not on clinical trials during the study period, were eligible. This study utilized iKnowMed electronic health records, Claims Data Warehouse, and Social Security Death Index. Progression-free survival (PFS) was assessed by Kaplan-Meier methods. RESULTS: A total of 266 patients met the selection criteria. A vast majority of the patients (249/266, 93.6%) received a trastuzumab + pertuzumab + taxane (H + P + T) regimen. The number of patients with prior adjuvant/neoadjuvant therapy was higher than the CLEOPATRA trial, but age (median 57 years) and percentage of visceral disease (74.8%) were similar. The most common adverse events were fatigue (50.8%), diarrhea (44.7%), nausea (35.3%), peripheral neuropathy (33.5%), neutropenia (24.9%), and rash (24.4%). The median PFS was 16.9 months (95% CI 14.2-19.7). CONCLUSIONS: In this retrospective study of patients with HER2-positive mBC receiving pertuzumab in the first-line setting, most patients were treated with H + P + T. The safety and PFS of H + P + T were consistent with those observed in the pivotal trial.