Table 1.
Inclusion criteria for MONARCH 1 and real-world chemotherapy cohort
| Key features | MONARCH 1 | Real-world cohorta |
|---|---|---|
| Indication | MBC | MBC |
| HR status | Positive | Positive |
| HER2 status | Negative | Negative |
| Prior endocrine therapy in adjuvant and/or metastatic setting | Yes | Not requireda but prior ET in metastatic disease explored in sensitivity analyses |
| Number of prior chemotherapy regimens in metastatic setting | 1 or 2 | 1 or 2 |
| ECOG PS | 0 or 1 | 0 or 1 |
| Prior taxane containing regimen in adjuvant or metastatic setting | Yes | Not requiredb |
| Prior CDK4 & 6 therapy | Not permitted | Not permitted |
| CNS metastases | Not permitted | Not permitted |
CDK Cyclin-dependent kinase, CNS central nervous system, ECOG PS eastern cooperative oncology group performance status, EHR electronic health record, ET endocrine therapy, HER2 human epidermal growth factor receptor 2, HR hormone receptor, MBC metastatic breast cancer
aAnalyses were conducted both requiring and not requiring (primary analysis) prior endocrine therapy in the metastatic setting
bPrior taxane use was ‘not required’ in the real-world chemotherapy cohort because the Flatiron Health EHR database has incomplete data in the adjuvant setting