Real-world Treatment Patterns and Effectiveness of Palbociclib and AI Therapy

Real-world Treatment Patterns and Effectiveness of Palbociclib in Combination With an Aromatase Inhibitor as Initial Endocrine Based Therapy in Metastatic/Advanced Breast Cancer

A retrospective observational analysis of de-identified Flatiron Health Analytic Database to describe patient characteristics, treatment patterns and effectiveness of Palbociclib + AI as first-line therapy in HR+/HER2- metastatic breast cancer (MBC) in the US clinical practices.

Utilizing de-identified data derived from the Flatiron Health Analytic Database, the retrospective observational study is to describe patient characteristics, treatment patterns and effectiveness of Palbociclib + AI as first-line therapy in HR+/HER2-MBC in the US real-world clinical practice setting. Patients will be evaluated retrospectively from index therapy date to death, or last visit in the database, whichever comes first. Descriptive and multivariate statistical analyses will be performed.

Inclusion Criteria:

1. Female sex

2. At least 18 years old at MBC diagnosis

3. Diagnosis of MBC at any point in patient history

   1. ICD-9 (174.x, 175.x) or ICD-10 (C50.xx) diagnosis of BC
   2. Confirmation of metastatic disease
   3. At least 2 document clinical visits
   4. Evidence of stage IV or recurrent MBC with a metastatic diagnosis date on or after 2011, as confirmed by unstructured clinical documents

4. HR+/HER2-

   1. HR+: ER+ or PR+ test before or up to 60 days after MBC diagnosis
   2. HER2-: any HER2 negative test and the absence of a positive test (IHC positive 3+, FISH positive/amplified, Positive NOS) before or up to 60 days after MBC diagnosis

5. Palbociclib + AI or letrozole as first-line therapy for MBC during the period from February/2015 through August /31/2018 (or 3 months prior to study cut-off date) to allow for a possible minimum follow-up time of 90 days until the study cutoff date. AI was administered within (±) 28 days of Palbociclib index date.

Exclusion Criteria:

1. Evidence of prior treatment with other CDK4/6I (Ribociclib or Abemaciclib), AI (Letrozole, Exemestane, and Anastrazole), Tamoxifen, Raloxifene, Toremifene, or Fulvestrant for MBC
2. First structured activity greater than 90 days after MBC diagnostic date
3. Treatment with a CDK4/6 inhibitor as part of a clinical trial