Overall survival associated with CDK4/6 inhibitors in patients with HR+/HER2– metastatic breast cancer in the United States: A SEER-Medicare population-based study
Menée à partir de données des registres américains des cancers et de la base Medicare portant sur 603 patientes atteintes d'un cancer du sein HR+ HER2- de stade métastatique (âge : supérieur ou égal à 65 ans), cette étude de cohorte rétrospective évalue l'efficacité, du point de vue de la survie globale, de l'ajout d'inhibiteurs de CDK4/6 à une thérapie endocrinienne
Background: Evidence on overall survival (OS) with cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors is generally limited to data from clinical trials or a few observational studies with limited generalizability to Medicare population. The aim of this study was to determine OS benefits associated with CDK4/6 inhibitors in older Medicare patients with hormone receptor (HR)–positive and human epidermal growth factor receptor-2 overexpressing (HER2–) metastatic breast cancer (MBC). Methods: In a retrospective cohort design, female patients aged ≥65 years with diagnosis of HR+/HER2– MBC from 2015 to 2017 who initiated first-line systemic therapy within 12 months of MBC diagnosis were selected from the Survey Epidemiology and End Results-Medicare database. The effect of treatment type (endocrine therapy [ET]+CDK4/6 inhibitor vs. ET alone) on OS was analyzed using Kaplan–Meier methods and multivariable Cox regression models. Adjusted hazard ratio (aHR) and 95% CIs were estimated. Results: A total of 630 eligible patients were identified (169 patients treated with ET+CDK4/6 inhibitor and 461 patients treated with ET alone). In the Kaplan–Meier analysis, OS rate at 3 years after first-line treatment initiation was 73.0% for ET+CDK4/6 inhibitor versus 49.1% for ET alone (log-rank p < .0001). In Cox regression analysis, first-line ET+CDK4/6 inhibitor therapy was associated with 41% lower rate of mortality versus ET alone (aHR, 0.590; 95% CI, 0.423–0.823). Conclusions: The findings of this real-world study demonstrate significant OS benefit associated with ET+CDK4/6 inhibitor therapy over ET alone in an older Medicare population of patients with HR+/HER2– MBC, largely consistent with the evidence from clinical trials.