Real-World Effectiveness of Palbociclib in Combination With an Aromatase Inhibitor

Real-World Treatment Effectiveness of Palbociclib in Combination With an Aromatase Inhibitor as 1st Line Therapy in Metastatic Breast Cancer

A retrospective study of de-identified (to preserve patient privacy) patient information from the Flatiron Health Analytic Database to compare effectiveness (i.e., overall survival) of first line palbociclib + aromatase inhibitor (AI) versus AI alone treatment in postmenopausal women or men with hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) metastatic breast cancer (MBC) in the United States clinical practices.

Inclusion Criteria:

• Confirmed HR+/HER2- status after MBC diagnosis.
• Received palbociclib + AI or AI as first-line therapy

Exclusion Criteria:

• Evidence of prior treatment with other CDK4/6I, AI, tamoxifen, raloxifene, toremifene, or Fulvestrant for MBC
• First structured activity greater than 90 days after MBC diagnostic date
• Treatment with a CDK4/6 inhibitor as part of a clinical trial