RW Treatment Patterns and Outcomes in Postmenopausal HR+/HER2- mBC Patients Treated With Palbociclib Plus Letrozole as Initial Endocrine Therapy at Community Oncology Practices in the U.S.

Real-World Treatment Patterns and Outcomes in Postmenopausal, Hormone-Receptor Positive, Human Epidermal Growth Factor Receptor 2 Negative, Metastatic Breast Cancer Patients Treated With Palbociclib Plus an Letrozole as Initial Endocrine Therapy at Community Oncology Practices in the U.S.

This is a retrospective, observational study that will document treatment patterns and clinical outcomes of postmenopausal patients diagnosed with HR+/HER2- mBC who received Palbociclib plus Letrozole as initial endocrine-based therapy in US community oncology network settings.

Inclusion Criteria:

• Patients must meet all of the following inclusion criteria to be eligible for inclusion in the study:

  1. Diagnosed with locoregional recurrent or metastatic female breast cancer.

  2. Pathologically confirmed HR-positive/HER2-negative diagnosis.

  3. Received treatment with palbociclib in combination with letrozole as initial endocrine-based therapy for advanced/metastatic breast cancer:

     1. Initiated treatment with palbociclib at least 3 months following the provider's first use of palbociclib following its FDA approval.
     2. At least 1 month of follow-up (at least one visit with the provider) after initiation of palbociclib.

  4. Postmenopausal (or receiving surgical or medical treatment to induce menopause) at the time of initiation of palbociclib.

  5. ≥18 year old at initiation of palbociclib.

     Exclusion Criteria:

• No exclusion criteria will be imposed for the selection of patients.