Baseline Characteristics and Secondary Medication Adherence Patterns Among Patients Receiving Tafamidis Prescriptions: A Retrospective Analysis Using a National Specialty Pharmacy Dispensing Database

Abstract

Introduction: Transthyretin amyloid cardiomyopathy (ATTR-CM) is a serious, underrecognized condition, which leads to heart failure and early mortality if left untreated. Until recently, heart transplantation was the only treatment for ATTR-CM. Regulatory approval of tafamidis transformed treatment for patients. In the phase 3 Transthyretin Amyloidosis Cardiomyopathy Clinical Trial (ATTR-ACT), which established the safety and efficacy of tafamidis, medication adherence was high with 97.2% of patients taking ≥80% of scheduled doses. Evidence of real-world adherence to cardiology drugs demonstrates low adherence and suboptimal outcomes; however, real-world adherence to tafamidis has not been investigated. The main objective of this study was to describe adherence patterns of patients filling tafamidis in the Symphony Health database. Methods: This retrospective analysis of the Symphony Health Solutions claims database used secondary adherence measures, including modified medication possession ratio (MPRm), days between fills adherence rate, and compliance rate, to assess adherence patterns of 2020 patients filling tafamidis free acid 61-mg capsules or tafamidis meglumine 4x20-mg capsules from June 1, 2019 to August 31, 2020. Results: Patients receiving a tafamidis formulation had characteristics consistent with the expected patient population; 71.6% were aged 75–84 years, 83.2% were male, and the highest proportion resided in the Northeast region (30.5%) of the United States. Adherence for tafamidis was high, as 75% to 100% of the patients across subgroups met or exceeded the commonly defined adherence threshold of 80%. Median number of refills ordered and received was six refills per patient. Most patients received refills with no gap (n=1633) or a gap <30 days (n=1267/1317 patients). Adherence was high across follow-up time, sex, and age subgroups. Adherence varied by geographic region, with the Northeast being significantly higher than the Midwest (mean MPRm 94.41% vs 88.21%, p=0.0007). Conclusion: These results provide evidence that real-world adherence to tafamidis in patients with ATTR-CM is high.