Real-World Data on First-Line Treatment of Hormone Receptor-Positive, HER2-Negative, Metastatic Breast Cancer in Brazil (BRAVE Study)

Introduction Endocrine therapy (ET) plus CDK4/6 inhibitors has become the standard first-line therapy for hormone receptor-positive/HER2-negative metastatic breast cancer (MBC). Utilizing real-world data, we aimed to characterize treatment patterns, assess the impact of health insurance type, and evaluate outcomes among Brazilian MBC patients with this subtype treated in the first-line setting. Patients and Methods This is an observational retrospective study assessing female patients aged ≥18 years diagnosed with HR+/HER2- MBC between January/2018 and December/2020 at 13 sites in Brazil. The primary objective was to describe the treatment patterns within both the public and private healthcare systems. Secondary outcomes were progression-free survival (PFS) and overall survival (OS). Results In total, 307 patients were included. The most frequent treatment was ET alone (42.4%), followed by chemotherapy (31.6%), and ET plus CDK4/6 inhibitors (25.1%). The greatest difference in access to treatment was observed in the use of ET plus CDK4/6 inhibitors between the private (48.3%) and public healthcare systems (2.6%), (p<0.0001). Of the 84 patients that received CDK4/6 inhibitors, ribociclib was the most used (56.0%). With a median follow-up of 32.2 months (95% CI: 29.4-34.4), the median PFS was 24.2 months (95% CI: 18.6-30.4) in the public and 23.80 months (95% CI: 18.3-34.2) in the private healthcare system (p=0.9294). The median OS was 52.7 months (95% CI: 49.4-NR) in the overall population. Conclusion ET remains the most used first-line treatment in Brazil. However, access to therapies varies significantly between public and private healthcare sectors. This disparity highlights inequality in access to treatment. MICROABSTRACT In this observational retrospective study, we investigated the treatment patterns and outcomes, impact of health insurance type, and outcomes of female patients with hormone receptor-positive/HER2-negative metastatic breast cancer treated in a first-line setting in Brazil. Real-world data from 307 patients revealed that CT was used in a third of patients, more frequently in the public health system, and there was a significant difference in CDK4/6 inhibitor access between healthcare systems impacting patients' outcomes.