Background: Pertuzumab was FDA-approved in 6/2012 for use in first-line in combination with trastuzumab (H) and docetaxel for patients (pts) with HER2-positive mBC. This retrospective study investigated the clinical characteristics, treatment patterns, safety, and outcomes for pts with HER2-positive mBC who received a P-containing regimen in first-line in US community oncology practices.

Methods: This study utilized iKnowMed electronic health records, Claims Data Warehouse, and Social Security Death Index. Pts with HER2-positive mBC, who received a P-containing regimen between 6/2012 and 6/2014 and were followed through 12/2014, had ≥2 visits within the McKesson Specialty Health/US Oncology Network, and were not on clinical trials during the study period, were eligible.

Results: Of the 322 pts who received a P-containing regimen in the first-line setting, 25% were ≥65 years of age, 63% were post-menopausal, 61% had hormone receptor-positive mBC, 84% had a performance status of 0 or 1, and 76% had a Charlson Comorbidities Index of 0. Twenty-one percent of pts had 1 site of metastasis noted, 32% had 2 sites, and 47% had 3 or more sites. Pts with de novo mBC made up 40% of this cohort. Of the pts with recurrent mBC, over 60% received H in the early-stage BC setting. In the first-line mBC setting, 93% of the 322 pts received H+P+taxane, and 7% received H+P with other chemotherapy agent(s). Common adverse events reported included: fatigue (49%), diarrhea (44%), nausea (33%), peripheral neuropathy (33%), neutropenia (24%), and rash (22%). Further analyses including outcomes of these 322 pts will be presented.

Conclusions: First-line P was given in combination with H and chemotherapy agent(s) (93% taxane). No new safety signals were observed. More details on the clinical characteristics, specific treatment patterns, and safety will be presented, along with the progression-free survival of these pts receiving first-line P-containing therapy in a real-world setting.

Citation Format: Robert N, Goertz H-P, Asmar L, Tseng W-Y, Jiao X, Portera C, Yoo B, Patt D, Antao V. Pertuzumab (P) use in first-line HER2-positive metastatic breast cancer (mBC) in US community oncology practices: Treatment patterns and outcomes. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-13.