P-VERIFY: Real-World Comparative Overall Survival and Progression-Free Survival of CDK4/6 Inhibitors Plus an Aromatase Inhibitor in Patients with HR+/HER2- Metastatic Breast Cancer in the USA-A Vodcast.

To date, there have been no head-to-head randomized controlled trial data comparing cyclin-dependent kinase 4/6 (CDK4/6) inhibitors in patients with HR+/HER2- metastatic breast cancer (mBC), and most prior real-world comparative effectiveness studies have been limited by short follow-up times and small patient sample sizes. In this vodcast, we provide an overview of two recent publications reporting overall survival (OS) and real-world progression-free survival (rwPFS) results from P-VERIFY, a retrospective comparative effectiveness study of CDK4/6 inhibitors plus an aromatase inhibitor (AI) among patients with HR+/HER2- mBC treated in routine clinical practice in the USA. P-VERIFY used the Flatiron Health Analytic Database to identify 9146 patients who initiated first-line (1L) treatment with palbociclib (n = 6831), ribociclib (n = 1279), or abemaciclib (n = 1036), plus an AI, between February 2015 and November 2023. In primary analyses, there were no significant differences in OS and rwPFS between treatment groups after stabilized inverse probability treatment weighting, with hazard ratios ranging from 0.95 to 0.98 across pairwise group comparisons (all P > 0.05). Findings remained generally consistent across sensitivity and subgroup analyses and in a subanalysis of patients who started treatment in 2017 or later, when all three CDK4/6 inhibitors were commercially available. Taken together, results from P-VERIFY, the largest real-world study to date evaluating CDK4/6 inhibitor comparative effectiveness, suggest that there are no significant differences in OS and rwPFS between 1L palbociclib, ribociclib, and abemaciclib, plus an AI, in patients with HR+/HER2- mBC in US routine clinical practice.