A Study of Real-World Outcomes of Ribociclib in First-Line Treatment for Metastatic HR+/HER2- Breast Cancer

Inclusion criteria:

* Had 1 or more paid pharmacy claims for ribociclib with the first claim for the CDK4/6i observed between 26 February 2018 and 31 December 2022 (i.e., during the index period)

  * With the index CDK4/6i used in combination with an endocrine-based therapy, that is an aromatase inhibitor (i.e., letrozole, anastrozole, or exemestane), or fulvestrant, as 1L treatment for mBC
  * With the endocrine therapy (ET) initiated within 60 days of the first paid pharmacy claim of the index CDK4/6i; ET may have been initiated no earlier than 60 days prior to the index date (expected window for insurance approval of the CDK4/6i as 1L treatment for mBC in a real-world setting)
* Adult who was 18 years of age or older as of the index date
* Had 2 or more medical service claims with a code for breast cancer (BC) separated by 30 days or more, and 1 or more claims with a code for BC prior to the index date
* Had 2 or more medical service claims with a code for a secondary neoplasm separated by 30 days or more, with the first code for a secondary neoplasm occurring not earlier than 30 days from the first diagnosis for BC, and 1 or more claims with a code for a secondary neoplasm prior to the index date
* Had continuous health plan enrollment for 12 months or more prior to and 1 month or more after the index date

Exclusion criteria:

* Patients who did not meet the inclusion criteria
* Had a diagnosis for other primary cancers (other than BC) before the first diagnosis for secondary neoplasm
* Had prior treatments for BC (i.e., chemotherapy, targeted therapy, ET \[except ≤60 days prior to index date\], or immunotherapy) during the 12-month washout period (relapsed/progressed ≤12 months prior to index date)
* Had prior surgical procedure for BC during the 12-month washout period (relapsed/progressed ≤12 months prior to index date)
* Had evidence of participation in a clinical trial prior to or at the index date (International Classification of Disease, 10th Edition, Clinical Modification \[ICD-10-CM\]: Z00.6)