Real-World Treatment Patterns and Clinical Effectiveness of Palbociclib Plus an Aromatase Inhibitor as First-Line Therapy in Advanced/Metastatic Breast Cancer: Analysis from the US Syapse Learning Health Network

• Published in: Current oncology (Toronto) Vol. 29; no. 2; pp. 1047 - 1061
• Main Authors: Law, Jeanna Wallenta, Mitra, Debanjali, Kaplan, Henry G, Alfred, Tamuno, Brufsky, Adam M, Emir, Birol, McCracken, Haley, Liu, Xianchen, Broome, Ronda G, Zhang, Chenan, DiCristo, Caroline, Chen, Connie
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 12-02-2022; MDPI AG
• Subjects: Antineoplastic Combined Chemotherapy Protocols; aromatase inhibitor; Aromatase Inhibitors - therapeutic use; Breast Neoplasms - pathology; Female; HR+/HER2; Humans; metastatic breast cancer; palbociclib; Piperazines; Pyridines; real-world data; Receptors, Estrogen - metabolism; Retrospective Studies; Treatment Outcome; real-world data; palbociclib; HR+/HER2; metastatic breast cancer; aromatase inhibitor
• DOI: 10.3390/curroncol29020089
• EISSN: 1718-7729
• ISSN: 1718-7729; 1198-0052

This retrospective single-arm study assessed real-world treatment patterns and clinical outcomes in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced/metastatic breast cancer (A/MBC) who received palbociclib plus an aromatase inhibitor as first-line therapy in US community health systems. Using electronic health records from the Syapse Learning Health Network, 242 patients were identified as having received first-line palbociclib plus an aromatase inhibitor between 3 February 2015, and 31 July 2019 (data cutoff 1 February 2020) resulting in a minimum potential 6-month follow-up period. In total, 56.6% of patients had de novo A/MBC at initial breast cancer diagnosis, 50.8% had bone-only disease, and 32.2% had visceral disease. Median follow-up was 22.4 months. Disease progression (26.4%) and intolerance/toxicity (14.9%) were the main reasons for treatment discontinuation. The median (95% CI) real-world progression-free survival was 31.7 (27.9-not estimable (NE)) months and 2-year estimated overall survival (OS) rate was 78.0%. In total, 25.6% of patients died; however, OS data are limited by the small population size and insufficient follow-up time. These real-world effectiveness outcomes complement findings from other real-world studies and randomized controlled trials and support palbociclib plus an aromatase inhibitor as first-line therapy for HR+/HER2- A/MBC.