Real-World Patterns of Everolimus Use in Patients with Metastatic Breast Cancer

Background: There is limited literature on patterns of everolimus use and subsequent hospitalizations and emergency room (ER) visits in real-world clinical practice. In this study, we describe patterns of everolimus use and hospitalizations and ER visits in a large cohort of patients with breast cancer (BC). Materials and Methods: Patients with BC treated with everolimus were identified in the MarketScan database from 2009 to 2016. The pattern of everolimus use and frequency of associated ER visits and hospitalizations during treatment (between the first claim and 30 days after the last claim for everolimus) were identified. Descriptive statistics and regression models were used. Results: A total of 3,556 everolimus users were identified (median age of 60 years; median days of use, 112). The initial prescribed dose was 10 mg in 74.8% of the patients. Compared with the initial dose, 23.5% of patients had a dose change. Forty-six percent of patients were hospitalized or had an ER visit during the treatment with everolimus. Age greater than 71, higher comorbidity score, treatment year prior to 2012, and lower initial dose were found to be significantly associated with ER visit/hospitalization in the regression models. Conclusions: A significant proportion of patients receiving everolimus had an ER visit or hospitalization during the use of everolimus. These results provide data regarding risks and benefits of treatment with everolimus. These results will be helpful in identifying patients at higher risk of hospitalizations or ER visits and facilitate evidence-based decision making to avoid serious complications. Implications for Practice: Everolimus, a mammalian target of rapamycin inhibitor, is approved in combination with exemestane in patients with hormone receptor–positive tumors previously treated with anastrozole or letrozole. As new drugs become available, it is crucial to understand the adverse events and potential complications associated with the use of such drugs in the general population, outside of the controlled clinical trial setting. This study describes the patterns of everolimus use and adverse events, including hospitalization and emergency room visits, in a large cohort of patients with metastatic breast cancer in routine practice.