Key Points
• Conclusion/Relevance: “The adoption of CDK4/6i + AI as a first-line treatment for HR-positive, HER2-negative MBC in Alberta is justified based on our favourable PFS and early OS outcomes.”
• In the current retrospective, population-based, cohort study, Canadian researchers assessed the cases of 316 patients with HR-positive, HER2-negative metastatic breast cancer (MBC) who received a CDK4/6 inhibitor in combination with an aromatase inhibitor (AI) as first-line treatment in the metastatic setting.
• Following a median follow-up of 28.1 months, the median PFS was 37.9 months. Although the median overall survival (OS) was not reached, the 30-month OS was 74% and the 36-month OS was 68%.
• “Several factors may have positively influenced PFS in our cohort,” the authors noted. “A large proportion of our patients had a single metastatic site …. Our population may have been subjected to less frequent clinical/imaging assessments for progression in comparison with trial protocols or real-world studies from jurisdictions with privately administered care, and classification of progression was not based strictly on RECIST but rather overall physician evaluation. Finally, our duration of follow-up was relatively long.”
• According to the authors, the strengths of this real-world study include its utilization of population-level data, its novel investigation of delayed CDK4/6i start as a variable in the survival analyses, and its incorporation of subsequent therapy information.
• The current study had certain limitations. For instance, the population-level data were likely incomplete. Furthermore, the researchers did not have access to a concurrent cohort of patients treated with AI monotherapy.