Health impact of tafamidis in transthyretin amyloid cardiomyopathy patients: an analysis from the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) and the open-label long-term extension studies

Abstract

Aim

The Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) showed that tafamidis reduced all-cause mortality and cardiovascular-related hospitalizations in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). This study aimed to estimate the impact of tafamidis on survival and quality-adjusted life-years (QALYs).

Methods and results

A multi-state, cohort, Markov model was developed to simulate the disease course of ATTR-CM throughout a lifetime. For survival extrapolation, survival curves were fitted by treatment arm and New York Heart Association (NYHA) Class I/II (68% of patients) and NYHA Class III (32% of patients) cohorts using the individual patient-level data from both the ATTR-ACT and the corresponding long-term extension study. Univariate and multivariate sensitivity analyses were conducted. The predicted mean survival for the total population (NYHA Class I/II + III) was 6.73 years for tafamidis and 2.85 years for the standard of care (SoC), resulting in an incremental mean survival of 3.88 years [95% confidence interval (CI) 1.32–5.66]. Of the 6.73 life-years, patients on tafamidis spend, on average, 4.82 years in NYHA Class I/II, while patients on SoC spend an average of 1.60 life-years in these classes. The combination of longer survival in lower NYHA classes produced a QALY gain of 5.39 for tafamidis and 2.11 for SoC, resulting in 3.29 incremental QALYs (95% CI 1.21–4.74) in favour of tafamidis.

Conclusion

Based on the disease simulation model results, tafamidis is expected to more than double the life expectancy and QALYs of ATTR-CM patients compared to SoC. Longer-term follow-up data from the ATTR-ACT extension study will further inform these findings.

Clinical trials.gov identifier

NCT01994889 (date of registration: 26 November 2013).