A prospective study of adherence to lenalidomide for multiple myeloma using Medication Event Monitoring System (MEMS) caps

PurposeIn patients with multiple myeloma, characterizing adherence to orally administered therapies, such as lenalidomide, is critical given their frequent use and potential for poorer outcomes associated with nonadherence. However, little data exist using prospective measures of adherence in this population. Our study piloted use of Medication Event Monitoring System (MEMS) caps and the patient-reported Brief Adherence Rating Scale (BARS) for 3 months in older adults with multiple myeloma. MethodsWe enrolled 13 patients with multiple myeloma receiving lenalidomide. Baseline characteristics were summarized; mean adherence to lenalidomide was reported with 95% confidence intervals. ResultsThe median follow-up was 84 days. Of the 12 participants evaluable, median adherence, as assessed by the MEMS cap data, was 98%. Only 5 had 100% adherence. Deviations from intended use included missed prescribed doses made up during scheduled off week, additional days off between cycles, or taking fewer than anticipated days off. None of these events evident in MEMS data were self-disclosed. The mean difference in adherence estimated between the BARS and MEMS caps was 2%. ConclusionIn this small sample, the observed adherence was higher than reported in retrospective studies using Medication Possession Ratio as a proxy for adherence. The BARS can be easily integrated into clinical encounters but has potential for reporting bias. MEMS caps can help characterize patterns of nonadherence, though there are limitations to their utility and the data can require thorough manual review to reconcile suspected occurrences of nonadherence. Studies should use more than 1 complementary measure of adherence. Clinicaltrials.gov ID: NCT03779555, Registered 12/19/2018