Tafamidis in Patients with ATTR-CM

In a 2018 paper, the phase 3 ATTR-ACT investigators demonstrated treatment with tafamidis led to reductions in all-cause mortality and cardiovascular-related hospitalizations, and directionally positive echocardiographic findings in patients with transthyretin amyloid cardiomyopathy (ATTR-CM), compared with placebo.¹ Although these data are undoubtedly positive, the relationships between these clinical benefits and observed differences in cardiac remodeling between treatment-naïve and tafamidis-treated patients had not yet been well-defined. A study using a prospective heart failure registry at the Medical University of Vienna aimed to determine the impact of tafamidis treatment on cardiac amyloid deposition and relevant biomarkers in patients with ATTR-CM.

Patients diagnosed with ATTR-CM between May 2015 and June 2020 were screened for eligibility. Patients were excluded if they had the presence of a TTR mutation or were unable to undergo baseline cardiac magnetic resonance (CMR) imaging and follow-up with late gadolinium enhancement (LGE) and T1 mapping.

Of the 125 patients with ATTR-CM screened for eligibility, 69 patients with wild-type ATTR-CM were considered eligible for the study, which included 3 cohorts: treatment-naïve control cohort (n = 19), tafamidis 20-mg cohort^a (n = 15), and tafamidis 61-mg cohort (n = 35). CMR was performed at baseline and at a median follow-up of 9, 11, and 12 months for the tafamidis 61-mg group, tafamidis 20-mg group, and control group, respectively.

Significant beneficial effects were seen for the tafamidis 61-mg patients in left ventricular mass index (LVMI; P = .036), extracellular volume (ECV; P = .030), LGE pattern (P = .015), and left ventricular ejection fraction (LVEF; P = .035) compared with treatment-naïve patients who experienced increases in LVMI and ECV, LGE-pattern progression, and LVEF decline. The tafamidis 61-mg cohort also saw significant benefits in New York Heart Association functional class (P = .004), 6-minute walk distance (6MWD; P = .005), and serum N-terminal pro B-type natriuretic peptide levels (NT-proBNP; P = .002) compared with the control group. In contrast, CMR findings in the tafamidis 20-mg cohort and the control cohort did not significantly differ. However, clinical comparison of these 2 cohorts favored the tafamidis 20-mg cohort in serum NT-proBNP levels (P = .003) and 6MWD (P = .023). When comparing CMR parameters with cardiac biomarkers longitudinally, a significant positive correlation between ECV and serum NT-proBNP levels was discovered for the entire study population (P = .034).

These results provide evidence that treatment of patients with ATTR-CM with tafamidis 61 mg daily delays cardiac changes compared with treatment-naïve patients. Despite these positive findings, further research should be conducted with longer study durations to gain a better sense of the long-term impact of tafamidis on cardiac structure and function changes.^a The dosing for the tafamidis 20-mg cohort was based on the approval in transthyretin-mediated amyloid polyneuropathy.

Reference

1. Maurer MS, Schwartz JH, Gundapaneni B, et al. Tafamidis treatment for patients with transthyretin amyloid cardiomyopathy. N Engl J Med. 2018;379(11):1007-1016.

Source

Rettl R, Mann C, Duca F, et al. Tafamidis treatment delays structural and functional changes of the left ventricle in patients with transthyretin amyloid cardiomyopathy. Eur Heart J Cardiovasc Imaging. 2022;23(6):767-780.