Effect of tafamidis treatment on echocardiographic measures of heart structure and function in Chinese patients with transthyretin amyloid cardiomyopathy

Abstract Background A multicenter, open-label, post-approval commitment study previously demonstrated the safety and efficacy of tafamidis in Chinese patients with transthyretin amyloid cardiomyopathy (ATTR-CM). This post hoc analysis evaluated patients’ structural and functional echocardiographic changes during treatment. Methods Data were analyzed from 53 Chinese patients with ATTR-CM and an end-diastolic interventricular septal (IVS) wall thickness > 12 mm. Results At baseline, patients’ mean (standard deviation [SD]) age was 60 (12) years, 89% were male, and 94% had variant ATTR-CM. The majority (81%) had New York Heart Association class II symptoms (class I: 6%; class III: 13%). Patients’ mean (SD) baseline left ventricular (LV) ejection fraction was 53% (10.9), stroke volume was 46 (17.9) mL, LV global longitudinal strain (GLS) was −14% (3.0), IVS wall thickness was 17 (3.5) mm, and posterior wall thickness (PWT) was 15 (3.4) mm. Patients received open-label tafamidis free acid 61 mg for 12 months with echocardiographic assessments at baseline, month 6, and month 12. After 6 and 12 months of treatment there were no clinically relevant mean changes from baseline in cardiac structure or function measures. Overall, 85% of patients had < 5% decrease in LV ejection fraction, 83% had < 5 mL decrease in stroke volume, 83% had < 1% increase in GLS, 80% had < 2-mm increase in IVS wall thickness, and 85% had < 2-mm increase in PWT from baseline to month 12. Conclusion Stability in echocardiographic measures of cardiac structure and function was observed over 12 months of tafamidis treatment in Chinese patients, predominantly with variant ATTR-CM. ClinicalTrials.gov, NCT04814186, Registered 10 March 2021, https://clinicaltrials.gov/study/NCT04814186