Tafamidis treatment for transthyretin amyloid cardiomyopathy: results from an open-label, early-access, long-term study extension in an all-comers population

Abstract Background In the pivotal Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT NCT01994889), tafamidis significantly reduced mortality and cardiovascular hospitalization in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). Given the high clinical unmet need and the favorable benefit-to-risk profile of tafamidis, there was a justification to provide patients with an option for early access to treatment as part of the ATTR-ACT long-term extension study (LTE; NCT02791230). Purpose To assess long-term safety in an all-comers population receiving early access to tafamidis. Methods Following protocol amendment (20 July 2018), patients with ATTR-CM, not previously enrolled in ATTR-ACT, and without commercial access to tafamidis, were enrolled in the LTE early-access study arm in 13 countries. Patients received open-label, once-daily tafamidis free acid 61 mg for up to 60 months, until they gained product access by prescription or study discontinuation by the sponsor. All-cause and cardiovascular (CV)-related mortality, CV-related hospitalization, and treatment-emergent adverse events (TEAEs) were assessed. Results Of 1481 patients enrolled in the early-access cohort, 1476 received at least one dose of tafamidis and were included in the analysis. Mean (SD) age at enrollment was 76.5 (7.8) years old, 37.5% were ≥80 years old, and 88.8% were male. Most patients (85.6%) had wild-type ATTR-CM, and 14.9%, 52.9%, 30.8%, and 1.3% were in New York Heart Association (NYHA) Class I, II, III, and IV, respectively. Over a mean (SD) follow-up period of 17.7 (13.8) months, all-cause and CV-related mortality rates were 23.4% and 13.8%, respectively (Table). Mean frequency of CV-related hospitalization per year was 0.28 (0.60). Serious TEAEs and TEAEs leading to discontinuation of the study were observed in 0.6% of patients (both); no new safety signals were identified. Conclusions Findings from the early-access cohort of the ATTR-ACT LTE highlight the safety of tafamidis treatment in an all-comers ATTR-CM patient population.