Real-world dosing patterns of everolimus-based lines of therapy among post-menopausal women with hormone receptor-positive and human epidermal growth factor receptor-negative (HR+/HER2-) metastatic breast cancer (mBC).

Abstract

e12528 Background: This study sought to describe dosing patterns of post-menopausal women with HR+/HER2- mBC treated with everolimus during a second or later lines of therapy in the US. Methods: MarketScan Commercial and Medicare Supplemental administrative claims databases were used to select post-menopausal HR+/HER2- mBC females who initiated an everolimus-based line of therapy during 1/1/2013- 7/31/2016. The first secondary malignancy diagnosis was the index date. Patients had 6 months of continuous enrollment in their health plans pre- and post- index, and were followed until the earliest date of disenrollment, inpatient death, or end of study. A line of therapy ended at discontinuation (gap >60 days in all treatment) or switch to a new treatment. Dose modification during 2L, 3L, or 4L was defined by a change in daily dose of >2.5 mg compared to the prior prescription and treatment interruption was defined as a gap >60 days of everolimus followed by a restart of therapy during follow-up. Results: There were 645 mBC patients with everolimus-based line(s) of therapy eligible for analysis (mean age = 61.1 [SD 11.7], mean days to treatment initiation = 33.4 [SD 65.1]). Across all lines, the majority (72.5%-80.8%) of patients were on a combination regimen with endocrine therapy and <10% were on a combination regimen with chemotherapy. Among patients with valid dose data (96.2%), mean initial dose in mg was 8.6 (SD 2.6) in 2L, 8.3 (SD 2.8) in 3L and 9.1 (SD 5.9) in 4L, the majority (71.4%-79%) did not have a dose modification, and <5% had a treatment interruption (Table). Conclusions: Results from this analysis of real-world data suggest that 71%-79% of patients did not experience any modification to the initial dose during an everolimus-based 2L, 3L, or 4L of therapy and less than 4% experienced a treatment interruption. [Table: see text]