The treatment landscape for women with HR+/HER2- advanced and metastatic breast cancer (A/MBC) is changing as new agents are being combined with more established treatments to achieve greater efficacy in combating resistant and unresponsive disease. The present study is designed to describe patient characteristics, treatment patterns, and clinical outcomes in a cohort of women with HR+/HER2- A/MBC treated with palbociclib plus aromatase inhibitor (P+AI) or palbociclib plus fulvestrant (P+FV) in the US community oncology setting.


Retrospective medical record data from adult women diagnosed with HR+/HER2- A/MBC who initiated P+AI or P+FV for treatment of A/MBC on or after February 3, 2015 were collected from the Vector Oncology Data Warehouse, a network comprised of 10 community oncology practices across the US. Descriptive analyses were performed on patient characteristics, treatment patterns, and clinical outcomes. Time to event outcomes (progression-free rate (PFR) and survival rate (SR)) at 12 (PFR-12, SR-12) and 24 (PFR-24, SR-24) months for the P+AI combination as first line endocrine therapy and 12 and 18 months for the P+FV combination as treatment following prior endocrine based therapy in either the adjuvant or metastatic setting.


Among 304 patients who received palbociclib combination therapy, 281 (92.4%) received it per labeled indication. Of the 281 on-label users, the focus of reporting here, 233 (82.9%) received P+AI as their initial endocrine therapy after A/MBC diagnosis; 48 (17.1%) received P+FV after prior endocrine therapy for breast cancer. Patient mean age (SD) was 63.1 (11.4) and 68.2 (10.2) years for patients receiving P+AI and P+FV, respectively. Patients were predominantly white (74.2% for P+AI and 77.1% for P+FV patients).The initial dosing for palbociclib was 125mg/day in 85.4% (n=199) of P+AI and 79.2% (n=38) of P+FV patients. Among patients who received P+AI, PFR-12 was 69.8% and PFR-24 was 46.8% with median follow up time of 10.8 months and 36.8% of progression events. The SR-12 was 89.8% and SR-24 was 71.4%. For patients who received P+FV, PFR-12 was 43.5% and PFR-18 was 39.9% with a median follow up time of 7.6 months and 50.0% of progression events. The SR-12 was 76.3% and SR-18 was 65.0%.


This study provides real-world assessment of treatment patterns and clinical outcomes of patients with HR+/ HER2- A/MBC who received palbociclib in combination with an AI or a FV in US community oncology settings. These findings demonstrate the benefit of palbociclib combination therapy in a diverse real world population.

Sponsor: Pfizer, Inc.

Citation Format: Trocio J, Lin J, Fisher MD, Hu N, Davis C, McRoy L, Walker MS, Iyer S. Real-world treatment patterns and clinical outcomes with palbociclib combination therapy received in US community oncology practices [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-29.