Amass, Leslie

Abstract Background Tafamidis (meglumine 80 mg/free acid 61 mg) is approved to treat transthyretin amyloid cardiomyopathy (ATTR-CM). In the pivotal phase 3 study ATTR-ACT, tafamidis significantly reduced all-cause mortality (ACM) and cardiovascular-related hospitalisations in patients with ATTR-CM (1). Real-world data further extend and support the benefit of long-term tafamidis for improving survival in contemporary patients with ATTR-CM (2). Purpose To further compare survival in a contemporary, real-world, pooled, matched cohort of patients with ATTR-CM treated vs not treated with tafamidis, adjusted for potential prognosticators of treatment effect. Methods Data were pooled from 2 studies. One study included a contemporary cohort of patients with ATTR-CM who received early access to tafamidis in the ATTR-ACT long-term extension (LTE) study but did not participate in the parent study. The other study included a contemporary cohort of patients from the Transthyretin Amyloidosis Outcomes Survey (THAOS; NCT00628745) with predominantly cardiac or mixed phenotype ATTR-CM enrolled between 2019–2023 who received tafamidis throughout the study or never received tafamidis. THAOS was a longitudinal, observational, phase 4 study of patients with transthyretin amyloidosis and asymptomatic gene carriers. Treated patients were pooled from the 2 studies; all received the approved dose of tafamidis. Untreated patients were from THAOS. A propensity score matching procedure was used to match treated and not treated patients 1:1 on 3 significant variables identified from a multivariate logistic regression analysis: baseline age, New York Heart Association (NYHA) class and phenotype (cardiac, mixed); other variables considered were sex, estimated glomerular filtration rate (eGFR), follow-up time and modified body mass index (mBMI). Results In all, 566 patients (283 treated, 283 not treated) were included; 85 treated patients were from the LTE study and 198 were from THAOS. In treated and not treated patients, respectively, median age at enrolment was 78.0 and 78.7 years, and 89.0% and 83.4% were male (Table). The estimated adjusted survival probabilities for ACM for treated vs not treated patients were 78.0% vs 67.9% at 30 months and 70.2% vs 57.9% at 42 months (Figure). The hazard ratio (HR) for time to event for ACM was 0.62 (95% CI 0.41–0.92), favouring tafamidis. Conclusions This matched-cohort analysis showed better survival in a contemporary, real-world cohort of patients with ATTR-CM receiving the approved dose of tafamidis vs those not treated. These findings further extend results of ATTR-ACT to contemporary populations of patients with ATTR-CM treated clinically with tafamidis. These data show greater effectiveness of tafamidis for ATTR-CM in clinical practice than observed in earlier clinical trials, which may reflect earlier diagnosis and treatment in contemporary patients.

Abstract Introduction Transthyretin amyloidosis (ATTR amyloidosis) is a rare, life-threatening disorder caused by the deposition of amyloid fibrils composed of misfolded transthyretin (TTR). ATTR amyloidosis may arise from mutations in TTR or from aggregation of wild-type TTR (ATTRwt). ATTR amyloidosis with predominantly symptoms of cardiomyopathy (ATTR-CM) includes both hereditary and wild-type forms of the disease. Purpose To describe clinical history and disease presentation in a large population of patients with wild-type ATTR-CM from the Transthyretin Amyloidosis Outcomes Survey (THAOS). THAOS is an ongoing, global, longitudinal, observational survey of patients with ATTR amyloidosis, including both inherited and wild-type disease, and asymptomatic patients with TTR mutations. Methods Data from ATTRwt patients were extracted from THAOS (cut-off date: January 16, 2019) and demographic and clinical characteristics reported using descriptive statistics. Results There were 758 ATTRwt patients in THAOS (95% male). The majority of patients (69.3%) were in the United States, with the remainder in Italy (11.1%), Germany (7.3%), Spain (5.3%), and other countries (7.1%). Most patients (86.3%) were Caucasian, with 3.3% being of African Descent and 3.1% being of other races/ethnicities (7.4% missing data). The median (10–90th percentile) age at symptom onset was 69.7 (54.0–81.3) years and the median (10–90th percentile) time from symptom onset to diagnosis was 3.9 (0.1–17.8) years. Median (10–90th percentile) age at enrollment in THAOS was 76.4 (67.2–85.2) years. Nearly all subjects had either a cardiac (59.6%) or mixed cardiac and neurologic (36.5%) phenotype. At enrollment, 97.1% (577 of 594 patients assessed) had an abnormal ECG, with the prevalence of low voltage being 20.8% (115 of 552) and prevalence of left-ventricular hypertrophy being 2.1% (16 of 758). Atrial fibrillation was documented in 55% of patients (208 of 378). The mean (standard deviation [SD]) left-ventricular septum thickness was 17.5 (3.5) mm (n=505; 94.9% with thickness >12 mm) and mean (SD) left-ventricular ejection fraction (LVEF) was 48.3% (13.2) (n=511; 48.0% with LVEF <50.0%). Other signs and symptoms at enrollment were compatible with a sensory neuropathy in 54.2% of patients, autonomic neuropathy in 33.5% of patients, and motor neuropathy in 29.1% of patients. Gastrointestinal symptoms related to ATTR amyloidosis were present in 10.4% of patients. Conclusions Although patients with wild-type ATTR-CM tend to be older Caucasian men with a mostly cardiac disease phenotype, the clinical spectrum of ATTRwt is heterogeneous and differs from the classic phenotype. Our findings show that ATTRwt should not be considered an exclusively cardiac disease and there is a need for both cardiologic and neurologic assessment of these patients. Further study is needed to determine if the non-cardiac manifestations are due to amyloidosis or more common causes in this older population. Acknowledgement/Funding This study was sponsored by Pfizer.