Real-World Utilization of Palbociclib as First-Line Treatment for Canadian HR+/HER2- Women with Metastatic Breast Cancer: Results from PALCAN Study.

Canadian real-world data (RWD) regarding palbociclib as a first-line therapy for patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC) is limited. The PALbociclib CANadian (PALCAN) study examined palbociclib utilization patterns as first-line treatment for HR+/HER2- MBC using Alberta health administrative data. The final PALCAN cohort included 472 female patients with a median age of 64 years and a median follow-up time of 22.8 months (IQR: 0.7-88.2). The median (95% CI) duration of treatment was 13.8 (12.7-15.1) months in the overall cohort (IQR: 5.6, 24.8 months), and the probability of treatment discontinuation within the first year was 45%. Aromatase inhibitors (AIs) and fulvestrant were the accompanying endocrine therapies (ETs) in 83% (N = 393) and 14% (N = 64) (15 with unknown accompanying therapy) of patients, respectively. The median duration of treatment for patients receiving an AI as an accompanying therapy was 15.1 (13.6-17.4) months and 7.9 months (5.8-12.6) for patients receiving fulvestrant, which may suggest endocrine resistance in the latter group. The PALCAN data provides insights into practice patterns and the effectiveness of palbociclib as a first-line therapy in female patients with HR+/HER2- breast cancer in the Canadian real-world setting.