Analysis of real-world treatment adherence in a cohort of 2,395 patients with metastatic renal cell carcinoma (mRCC).

Abstract

517 Background: Given recent European data highlighting the importance of real-world dose intensity(Cancer Med 2014; 3(6): 1517-26.), we sought to investigate real-world adherence in patients with mRCC from a US perspective. Methods: In this retrospective cohort study, patients with newly diagnosed mRCC were selected from the MarketScan Commercial and Medicare Supplemental administrative claims databases based on an index event from 1/1/2006 to 3/31/2014. First line (1L) therapy was defined as first prescription record post-index for any approved mRCC therapy; change in line of therapy was defined as a therapy switch. Adherence was measured using the medication possession ratio (MPR) during each and all lines. MPR was defined as total days of supply during the treatment period divided by total treatment period until the start of last treatment. Nonadherence was defined as an MPR <80%. Results: A total of 2,395 mRCC patients were identified as initiating 1L therapy. Across all treatments the mean MPR was 0.77 ± 0.20, which increased over time from 0.73 in 2006 to 0.81 in 2013. More than 50% of patients were nonadherent. During 1L, patients treated with sunitinib had significantly lower mean MPR compared with most other treatments (table). Adherence was higher during 2L (0.85 ± 0.18) vs 1L (0.80 ± 0.19). A larger proportion of patients who initiated therapy with temsirolimus were adherent compared with those who initiated with sunitinib (62% vs 38%). Additional analyses are being conducted to address adherence with alternative dosing schedules. Conclusions: Over half of treated mRCC patients were found to be nonadherent to therapy. Adherence was significantly better with IV administered temsirolimus relative to the reference oral therapy, sunitinib. Real-world analysis of treatment adherence provides information for clinicians in monitoring and optimizing targeted therapy. [Table: see text]