Effect of long-term tafamidis treatment on health-related quality of life in patients with transthyretin amyloid cardiomyopathy

AIMS

To evaluate the effect of long-term tafamidis treatment on health-related quality of life (HRQoL) in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) enrolled in the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) and long-term extension (LTE) study.

METHODS AND RESULTS

We examined change from baseline in Kansas City Cardiomyopathy Questionnaire overall summary (KCCQ-OS) and clinical summary (KCCQ-CS) scores in patients who received tafamidis meglumine 80 mg for 30 months in ATTR-ACT and tafamidis (meglumine 80 mg or bioequivalent free acid 61 mg) for 30 months in the LTE study, and in patients who received placebo for 30 months in ATTR-ACT and tafamidis for 30 months in the LTE study. In ATTR-ACT, 176 and 177 patients were randomized to tafamidis 80 mg and placebo, respectively. Patients who continuously received tafamidis had a 6- to 7-point reduction in least squares (LS) mean (standard error) KCCQ-OS and KCCQ-CS scores at month 30 (-6.25 [1.53] and -7.48 [1.39]), with little or no further decline over the next 30 months (-5.92 [1.77] and -9.21 [1.88] at month 60). Patients who received placebo in ATTR-ACT had a 20-point reduction in LS mean KCCQ-OS and KCCQ-CS scores at month 30 (-19.60 [1.94] and -19.90 [2.01]), but the decline slowed after initiating tafamidis (-24.70 [3.04] and -25.30 [3.36] at month 60).

CONCLUSION

Tafamidis reduced HRQoL decline in patients with ATTR-CM. Patients continuously treated with tafamidis for 60 months demonstrated stabilized HRQoL. In patients who initially received placebo in ATTR-ACT, tafamidis reduced the decline in HRQoL during the LTE study.

Effect of Tafamidis on Cardiac Function in Patients With Transthyretin Amyloid Cardiomyopathy: A Post Hoc Analysis of the ATTR-ACT Randomized Clinical Trial

Importance

Tafamidis has been shown to improve survival in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) compared with placebo. However, its effect on cardiac function has not been fully characterized.

Objective

To examine the effect of tafamidis on cardiac function in patients with ATTR-CM.

Design, Setting, and Participants

This was an exploratory, post hoc analysis of the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), a multicenter, international, double-blind, placebo-controlled phase 3 randomized clinical trial conducted from December 2013 to February 2018. The ATTR-ACT included 48 sites in 13 counties and enrolled patients aged 18 to 90 years with ATTR-CM. Data were analyzed from July 2018 to September 2023.

Intervention

Patients were randomized to tafamidis meglumine, 80 mg or 20 mg, or placebo for 30 months.

Main Outcomes and Measures

Patients were categorized based on left ventricular (LV) ejection fraction at enrollment as having heart failure with preserved ejection fraction (≥50%), mildly reduced ejection fraction (41% to 49%), or reduced ejection fraction (≤40%). Changes from baseline to month 30 in LV ejection fraction, LV stroke volume, LV global longitudinal strain, and the ratio of early mitral inflow velocity to septal and lateral early diastolic mitral annular velocity (E/e') were compared in patients receiving tafamidis, 80 mg, vs placebo.

Results

A total of 441 patients were randomized in ATTR-ACT, and 436 patients had available echocardiographic data. Of 436 included patients, 393 (90.1%) were male, and the mean (SD) age was 74 (7) years. A total of 220 (50.5%), 119 (27.3%), and 97 (22.2%) had heart failure with preserved, mildly reduced, and reduced LV ejection fraction, respectively. Over 30 months, there was less pronounced worsening in 4 of the echocardiographic measures in patients receiving tafamidis, 80 mg (n = 176), vs placebo (n = 177) (least squares mean difference: LV stroke volume, 7.02 mL; 95% CI, 2.55-11.49; P = .002; LV global longitudinal strain, -1.02%; 95% CI, -1.73 to -0.31; P = .005; septal E/e', -3.11; 95% CI, -5.50 to -0.72; P = .01; lateral E/e', -2.35; 95% CI, -4.01 to -0.69; P = .006).

Conclusions and Relevance

Compared with placebo, tafamidis, 80 mg, attenuated the decline of LV systolic and diastolic function over 30 months in patients with ATTR-CM. Approximately half of patients had mildly reduced or reduced LV ejection fraction at enrollment, suggesting that ATTR-CM should be considered as a possible diagnosis in patients with heart failure regardless of underlying LV ejection fraction.

Trial Registration

ClinicalTrials.gov Identifier: NCT01994889.

Tafamidis Efficacy Among Octogenarian Patients in the Phase 3 ATTR-ACT and Ongoing Long-Term Extension Study

BACKGROUND

Tafamidis was approved to treat patients with transthyretin amyloid cardiomyopathy (ATTR-CM) on the basis of findings from the phase 3 Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT).

OBJECTIVES

This study was a post hoc analysis exploring tafamidis efficacy in octogenarian patients.

METHODS

Analysis of patients aged <80 and ≥80 years in ATTR-ACT and its ongoing open-label long-term extension (LTE) study, where all patients receive tafamidis.

RESULTS

After 30 months in ATTR-ACT, least squares (LS) mean change from baseline in 6-minute walk test (6MWT) distance, N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration, and Kansas City Cardiomyopathy Questionnaire Overall Summary (KCCQ-OS) score were smaller (all P < 0.05) in patients aged ≥80 years treated with tafamidis (n = 51) vs placebo (n = 37). At the LTE study interim analysis, patients aged ≥80 years treated continuously with tafamidis had a smaller decline in KCCQ-OS score (P < 0.05) and trended toward longer median survival (45 vs 27 months; all-cause mortality HR: 0.6828 [95% CI: 0.4048-1.1517]; P = 0.1526) than those initially treated with placebo in ATTR-ACT. Similar efficacy was observed in patients aged <80 years in ATTR-ACT, including smaller LS mean change from baseline in 6MWT distance, NT-proBNP concentration, and KCCQ-OS score, and lower rate of cardiovascular-related hospitalizations with tafamidis (n = 125) vs placebo (n = 140). In the LTE study, patients aged <80 years treated continuously with tafamidis had a longer median survival (80 vs 41 months; HR = 0.4513 [95% CI: 0.3176-0.6413]; P < 0.0001) and a smaller decline in KCCQ-OS score than those initially treated with placebo.

CONCLUSIONS

The findings demonstrate tafamidis efficacy for patients with ATTR-CM both in those aged <80 and those aged ≥80 years. (Tafamidis in Transthyretin Cardiomyopathy Clinical Trial [ATTR-ACT]; NCT01994889/Long-term Safety of Tafamidis in Subjects With Transthyretin Cardiomyopathy; NCT02791230).

Improved long-term survival with tafamidis treatment in patients with transthyretin amyloid cardiomyopathy and severe heart failure symptoms

AIM

The value of disease-modifying therapies (such as tafamidis) in patients with transthyretin amyloid cardiomyopathy (ATTR-CM) and severe heart failure symptoms has been debated. This study assessed long-term all-cause survival in patients with New York Heart Association (NYHA) class III symptoms in the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) long-term extension (LTE) study.

METHODS AND RESULTS

At the baseline of ATTR-ACT, 55/176 (31.3%) patients receiving tafamidis 80 mg and 63/177 (35.6%) receiving placebo had NYHA class III symptoms. After 30 months of treatment, patients could join an ongoing LTE study to receive open-label tafamidis. In an interim analysis of the LTE study (August 2021), all-cause mortality was lower among patients with NYHA class III symptoms who received continuous tafamidis in ATTR-ACT and the LTE study (hazard ratio 0.64; 95% confidence interval 0.41-0.99; median follow-up: 60 months), as compared with those who received placebo in ATTR-ACT and tafamidis in the LTE study (median follow-up: 56 months). Similar findings were observed in patients with NYHA class I/II symptoms at baseline (0.50; 0.35-0.73; tafamidis 80 mg n = 121; placebo n = 114; median follow-up of 61 and 60 months, respectively).

CONCLUSION

We observed reduced all-cause mortality with continuous tafamidis treatment compared with delayed tafamidis treatment (placebo then tafamidis) in patients with NYHA class III symptoms at baseline over a median follow-up of ∼5 years. These findings demonstrate the value of tafamidis treatment in patients with ATTR-CM and severe heart failure symptoms, and emphasize the importance of early treatment.

CLINICAL TRIAL REGISTRATIONS

ClinicalTrials.gov NCT01994889 and NCT02791230.

Long-term survival in people with transthyretin amyloid cardiomyopathy who took tafamidis: A Plain Language Summary

WHAT IS THIS PLAIN LANGUAGE SUMMARY ABOUT?

This summary presents the results from an ongoing, long-term extension study that followed an earlier study called ATTR-ACT. People who took part in this extension study and ATTR-ACT have a type of heart disease known as transthyretin amyloid cardiomyopathy (ATTR-CM for short), which causes heart failure and death. In ATTR-ACT, people took either a medicine called tafamidis or a placebo (a pill that looks like the study drug but does not contain any active ingredients) for up to 2½ years. So far, in the long-term extension study, people have continued taking tafamidis, or switched from taking a placebo to tafamidis, for another 2½ years. Researchers looked at how many people died in ATTR-ACT and the extension study. The long-term extension study is expected to end in 2027, so these are interim (not final) results.

WHAT DID RESEARCHERS FIND OUT?

In the extension study of ATTR-ACT, the risk of dying was lower in people who took tafamidis continuously throughout ATTR-ACT and the extension study than in people who took placebo in ATTR-ACT and switched to tafamidis in the extension study.

WHAT DO THE RESULTS MEAN?

Taking tafamidis increases how long people with ATTR-CM live. People with ATTR-CM who take tafamidis early and continuously are more likely to live longer than those who do not. These results highlight the importance of early detection and treatment in people with ATTR-CM. Clinical Trial Registration: NCT01994889 (ClinicalTrials.gov) Clinical Trial Registration: NCT02791230 (ClinicalTrials.gov).

Atrial fibrillation as a prognostic factor for all-cause mortality in patients with transthyretin amyloid cardiomyopathy

Introduction

Atrial fibrillation (afib) and flutter (aflutter) are among the most common manifestations of transthyretin amyloid cardiomyopathy (ATTR-CM) [1–3]. Studies have suggested that afib does not influence mortality [3–6]. Tafamidis was approved for the treatment of ATTR-CM based on the landmark, placebo-controlled, Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), where all-cause mortality was a primary efficacy outcome [7].

Purpose

Evaluate whether afib/aflutter was prognostic for all-cause mortality in ATTR-ACT.

Methods

ATTR-ACT was a multinational, Phase 3, randomized study of patients with ATTR-CM receiving tafamidis meglumine (80 or 20 mg) or placebo over 30 months. This analysis describes the characteristics of patients with and without current/historical afib/aflutter at the baseline of ATTR-ACT. Current/historical afib/aflutter was then evaluated as an independent prognostic factor for all-cause mortality using Cox proportional hazards modelling.

Results

The 314/441 (71%) patients in ATTR-ACT with current/historical afib/aflutter were older, more commonly male, and White than those without (Table 1). A higher proportion of patients with current/historical afib/aflutter were NYHA class III and had a wild-type genotype than those without. Median 6MWT distance and the proportion of patients with preserved left ventricular ejection fraction (≥50%) were lower, GLS was less negative, and NT-proBNP and BUN were higher among those with current/historical afib/aflutter vs those without.

In ATTR-ACT, treatment, genotype, and NYHA class were included in the pre-specified Cox proportional hazards model assessing all-cause mortality. Once current/historical afib/aflutter was added to this model, all variables were found to be significant independent predictors of all-cause mortality (P&lt;0.05; Table 2). The risk of mortality was 45% higher (hazard ratio = 0.55 [95% CI: 0.37, 0.82]) among patients with current/historical afib/aflutter than in those without. In an expanded stepwise model selection analysis including 23 baseline demographic and clinical covariates, current/historical afib/aflutter was not a significant independent predictor. This model showed BUN and NT-proBNP concentrations, 6MWT distance, genotype, treatment, and GLS to be significant independent prognostic factors for all-cause mortality (P&lt;0.01; Table 2).

Conclusions

Patients in ATTR-ACT with ATTR-CM and current/historical afib/aflutter were older, more likely to be male, have a wild-type genotype, and more advanced heart failure than those without. A Cox model including treatment, genotype, and NYHA class identified current/historical afib/aflutter as a significant independent predictor of all-cause mortality. In an expanded stepwise selection model current/historical afib/aflutter remained important but was less prognostic compared to other covariates. Overall, these results demonstrate the importance of afib/aflutter in patients with ATTR-CM.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This study was sponsored by Pfizer.

How did transthyretin amyloid cardiomyopathy progress in patients who took placebo in the study ATTR-ACT? A plain language summary

WHAT IS THIS PLAIN LANGUAGE SUMMARY ABOUT?

This plain language summary describes some results of a study called ATTR-ACT. This was the first large study to include people with wild-type and hereditary transthyretin amyloid cardiomyopathy (ATTR-CM for short). ATTR-CM is a type of heart disease that happens when abnormal clumps of protein build up in the heart. This build-up prevents the heart from working properly, causing a condition called heart failure. Wild-type ATTR-CM happens for unknown reasons in some people as they get older. Hereditary ATTR-CM can happen because of changes in people's genes (known as gene variants or mutations).

IMPORTANT INFORMATION ABOUT ATTR-ACT

In this study, 441 people with ATTR-CM took either a medicine called tafamidis or a placebo (a capsule that looked like tafamidis but didn't contain any active medicine) by mouth for 30 months, once a day. The researchers' main aim was to find out how tafamidis treatment affected the risk of people dying or being admitted to the hospital for heart problems. They found that tafamidis lowered these risks by about one-third compared with placebo.

WHAT ELSE DID RESEARCHERS FIND OUT IN ATTR-ACT?

As described in this summary, after ATTR-ACT was completed, researchers looked back at the results from people who took placebo to learn how ATTR-CM progressed without treatment. The researchers found that about 4 in 10 people with wild-type ATTR-CM who took placebo died and 6 in 10 were admitted to the hospital because of heart problems over 30 months. People who took placebo also could not walk as far at the end of the study as they did at the start because their heart function worsened over time.

WHY ARE THESE RESULTS IMPORTANT?

By showing how ATTR-CM affects people's health when they do not take treatment, these results highlight the benefits of early diagnosis and treatment of ATTR-CM. ClinicalTrials.gov NCT number: NCT01994889.

Long-Term Survival With Tafamidis in Patients With Transthyretin Amyloid Cardiomyopathy

Background:

Tafamidis is approved in many countries for the treatment of transthyretin amyloid cardiomyopathy. This study reports data on the long-term efficacy of tafamidis from an ongoing long-term extension (LTE) to the pivotal ATTR-ACT (Tafamidis in Transthyretin Cardiomyopathy Clinical Trial).

Methods:

Patients with transthyretin amyloid cardiomyopathy who completed ATTR-ACT could enroll in an LTE, continuing with the same tafamidis dose or, if previously treated with placebo, randomized (2:1) to tafamidis meglumine 80 or 20 mg. All patients in the LTE transitioned to tafamidis free acid 61 mg (bioequivalent to tafamidis meglumine 80 mg) following a protocol amendment. In this interim analysis, all-cause mortality was assessed in patients treated with tafamidis meglumine 80 mg in ATTR-ACT continuing in the LTE, compared with those receiving placebo in ATTR-ACT transitioning to tafamidis in the LTE.

Results:

Median follow-up was 58.5 months in the continuous tafamidis group (n=176) and 57.1 months in the placebo to tafamidis group (n=177). There were 79 (44.9%) deaths with continuous tafamidis and 111 (62.7%) with placebo to tafamidis (hazard ratio, 0.59 [95% CI, 0.44–0.79]; P<0.001). Mortality was also reduced in the continuous tafamidis (versus placebo to tafamidis) subgroups of: variant transthyretin amyloidosis (0.57 [0.33–0.99]; P=0.05) and wild-type transthyretin amyloidosis (0.61 [0.43–0.87]; P=0.006); and baseline New York Heart Association class I and II (0.56 [0.38–0.82]; P=0.003) and class III (0.65 [0.41–1.01]; P=0.06).

Conclusions:

In the LTE, patients initially treated with tafamidis in ATTR-ACT had substantially better survival than those first treated with placebo, highlighting the importance of early diagnosis and treatment in transthyretin amyloid cardiomyopathy.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01994889 and NCT02791230.

Tafamidis and quality of life in people with transthyretin amyloid cardiomyopathy in the study ATTR-ACT: A plain language summary

This plain language summary describes the results of a study called ATTR-ACT, which was published in the American Journal of Cardiology. In ATTR-ACT, researchers looked at the effects of tafamidis treatment in people with transthyretin amyloid cardiomyopathy (called ATTR-CM for short). Tafamidis is currently available in the USA and other countries as an oral treatment for adults with ATTR-CM. In ATTR-ACT, 441 people with ATTR-CM from 13 different countries took either tafamidis or placebo by mouth for 30 months. First, researchers looked at the effects of tafamidis on the risk of death and hospitalization due to heart problems between the start and the end of the study; they found that these risks were about one-third lower with tafamidis compared with placebo. As described in this summary, researchers also looked at the effects of tafamidis on people's heart failure symptoms, quality of life, and general health over the 30-month study. People who took part in ATTR-ACT rated these effects using questionnaires filled out before, during, and after the study. More people who took tafamidis saw improvement or no change in their heart failure symptoms and quality of life than people who took placebo. In addition, compared with people taking placebo, people taking tafamidis had less worsening of their general health during the study. These results show the benefits of tafamidis in reducing the declines in quality of life and health that often occur with this debilitating disease. To read the full Plain Language Summary of this article, click on the View Article button above and download the PDF. Clinical Trial Registration: NCT01994889 (ClinicalTrials.gov).

Patients with transthyretin amyloid cardiomyopathy may have preserved, mildly reduced, or reduced ejection fraction

Background

Transthyretin amyloid cardiomyopathy (ATTR-CM) is an often-overlooked form of heart failure with preserved ejection fraction (HFpEF). Previous studies have demonstrated that relatively high proportions of older patients with HFpEF have underlying ATTR-CM. However, while ATTR-CM should not be overlooked as a cause of HFpEF, it also should not be assumed that all patients with ATTR-CM present with HFpEF.

Purpose

To categorise patients with ATTR-CM from a large clinical trial by left ventricular ejection fraction (LVEF) at enrolment in order to describe the prevalence of HFpEF, HF with mildly reduced EF (HFmrEF), and HF with reduced EF (HFrEF).

Methods

The Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) enrolled 441 patients with ATTR-CM, including both hereditary (ATTRv) and wild-type (ATTRwt) patients. In ATTR-ACT, all patients underwent echocardiography at enrolment using a standardised protocol, and all images were reviewed and analysed at an independent central laboratory. In this analysis of patient data at enrolment, all patients in ATTR-ACT were categorised by LVEF as: HFpEF (LVEF ≥50%), HFmrEF (LVEF 41–49%), or HFrEF (LVEF ≤40%). The proportions of patients in these LVEF categories in the sub-groups of race, sex, genotype, and disease severity (by NYHA class) were assessed, together with myocardial contraction fraction (MCF) in each category.

Results

In ATTR-ACT, there were 220 (50.5%) patients with HFpEF, 119 (27.3%) with HFmrEF, and 97 (22.3%) with HFrEF (Table). Five subjects with missing LVEF at enrolment were not categorized. Asian patients had the highest proportion with HFpEF, followed by White, then Black patients. The ATTRwt group had a higher proportion of patients with HFpEF than the ATTRv group. There were significant differences (as assessed by Chi-square test; P=0.0001) in the proportion of patients in each EF category between NYHA class I or II and NYHA class III patients. Median MCF was higher in NYHA class I/II (16.6%) than NYHA class III (14.8%) patients, and higher in patients with HFpEF compared with HFmrEF and HFrEF.

Conclusions

Not all patients with ATTR-CM have HFpEF. In this analysis of patients at enrolment in ATTR-ACT half had mildly reduced or reduced LVEF, with even higher proportions of reduced EF observed in Black patients, ATTRv patients, and patients with worse functional class (NYHA class III). These data demonstrate that ATTR-CM should be considered as a possible diagnosis in all patients with HF regardless of EF.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Pfizer Table 1

Natural history and progression of transthyretin amyloid cardiomyopathy: insights from ATTR-ACT

Aims

Transthyretin amyloid cardiomyopathy (ATTR‐CM) is a progressive, fatal disorder that remains underdiagnosed. The Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR‐ACT) was the first large clinical trial to include both wild‐type (ATTRwt) and hereditary (ATTRv) patients. A description of the natural history of ATTR‐CM, utilizing data from placebo‐treated patients in ATTR‐ACT, will provide a greater understanding of presentation and progression of ATTR‐CM and may aid in disease awareness, earlier diagnosis and treatment monitoring.

Methods and results

Changes in clinical endpoints (mortality, cardiovascular [CV]‐related hospitalizations, 6‐min walk test [6MWT] distance and Kansas City Cardiomyopathy Questionnaire Overall Summary [KCCQ‐OS] score) from baseline to Month 30 in the 177 patients (134 ATTRwt, 43 ATTRv) who received placebo in ATTR‐ACT were assessed. ATTRwt patients tended to have less severe disease at baseline. Over the duration of ATTR‐ACT, there were 76 (42.9%) all‐cause deaths, and 107 (60.5%) patients had a CV‐related hospitalization. There was a lower proportion of all‐cause deaths in ATTRwt (49, 36.6%) than ATTRv (27, 62.8%). There was a similar, steady decline in mean (SD) 6MWT distance from baseline to Month 30 in ATTRwt (93.9 [93.7] m) and ATTRv (89.1 [107.2] m) patients. The decline in mean (SD) KCCQ‐OS score was less severe in ATTRwt (13.8 [20.7]) than ATTRv (21.0 [26.4]) patients.

Conclusions

Patients with ATTR‐CM experience a severe, progressive disease. In ATTR‐ACT, placebo‐treated patients with ATTRv, compared with ATTRwt, had more severe disease at baseline, and their disease progressed more rapidly as shown by mortality, hospitalizations and quality of life over time.

Causes of Cardiovascular Hospitalization and Death in Patients With Transthyretin Amyloid Cardiomyopathy (from the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial [ATTR-ACT])

In the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), tafamidis significantly reduced mortality and cardiovascular (CV)-related hospitalizations compared with placebo in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). This analysis aimed to assess the causes of CV-related death and hospitalization in ATTR-ACT to provide further insight into the progression of ATTR-CM and efficacy of tafamidis. ATTR-ACT was an international, double-blind, placebo-controlled, and randomized study. Patients with hereditary or wild-type ATTR-CM were randomized to tafamidis (n = 264) or placebo (n = 177) for 30 months. The independent Endpoint Adjudication Committee determined whether certain investigator-reported events met the definition of disease-related efficacy endpoints using predefined criteria. Cause-specific reasons for CV-related deaths (heart failure [HF], arrhythmia, myocardial infarction, sudden death, stroke, and other CV causes) and hospitalizations (HF, arrhythmia, myocardial infarction, transient ischemic attack/stroke, and other CV causes) were assessed. Total CV-related deaths was 53 (20.1%) with tafamidis and 50 (28.2%) with placebo, with HF (15.5% tafamidis, 22.6% placebo), followed by sudden death (2.7% tafamidis, 5.1% placebo), the most common causes. The number of patients with a CV-related hospitalization was 138 (52.3%) with tafamidis and 107 (60.5%) with placebo; with HF the most common cause (43.2% tafamidis, 50.3% placebo). All predefined causes of CV-related death or hospitalization were less frequent with tafamidis than placebo. In conclusion, these data provide further insight into CV disease progression in patients with ATTR-CM, with HF the most common adjudicated cause of CV-related hospitalization or death in ATTR-ACT. Clinical trial registration ClinicalTrials.gov: NCT01994889.

Efficacy of Tafamidis in Patients With Hereditary and Wild-Type Transthyretin Amyloid Cardiomyopathy: Further Analyses From ATTR-ACT

OBJECTIVES

Tafamidis is an effective treatment for transthyretin amyloid cardiomyopathy (ATTR-CM), this study aimed to determine whether there is a differential effect between variant transthyretin amyloidosis (ATTRv) and wild-type transthyretin (ATTRwt).

BACKGROUND

ATTR-CM is a progressive, fatal disorder resulting from mutations in the ATTRv or the deposition of denatured ATTRwt.

METHODS

In pre-specified analyses from ATTR-ACT (Tafamidis in Transthyretin Cardiomyopathy Clinical Trial), baseline characteristics, all-cause mortality, and change from baseline to month 30 in 6-min walk test distance and Kansas City Cardiomyopathy Questionnaire Overall Summary score were compared in patients with ATTRwt and ATTRv.

RESULTS

There were 335 patients with ATTRwt (201 tafamidis, 134 placebo) and 106 with ATTRv (63 tafamidis, 43 placebo) enrolled in ATTR-ACT. Patients with ATTRwt (vs. ATTRv) had less advanced disease at baseline and a lower rate of disease progression over the study. The reduction in all-cause mortality with tafamidis compared with placebo was not different between ATTRwt (hazard ratio: 0.706 [95% confidence interval (CI): 0.474 to 1.052]; p = 0.0875) and ATTRv (hazard ratio: 0.690 [95% CI: 0.408 to 1.167]; p = 0.1667). Tafamidis was associated with a similar reduction (vs. placebo) in the decline in 6-min walk test distance in ATTRwt (mean ± SE difference from placebo, 77.14 ± 10.78; p < 0.0001) and ATTRv (79.61 ± 29.83 m; p = 0.008); and Kansas City Cardiomyopathy Questionnaire Overall Summary score in ATTRwt (12.72 ± 2.10; p < 0.0001) and ATTRv (18.18 ± 7.75; p = 0.019).

CONCLUSIONS

Pre-specified analyses from ATTR-ACT confirm the poor prognosis of untreated ATTRv-related cardiomyopathy compared with ATTRwt, but show the reduction in mortality and functional decline with tafamidis treatment is similar in both disease subtypes. (Safety and Efficacy of Tafamidis in Patients With Transthyretin Cardiomyopathy [ATTR-ACT]; NCT01994889).

Long-term survival with tafamidis in patients with transthyretin amyloid cardiomyopathy

Background

The Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), demonstrated that tafamidis was an effective treatment for patients with transthyretin amyloid cardiomyopathy (ATTR-CM). Tafamidis, at an 80 mg daily dose, was subsequently approved in several countries for the treatment of ATTR-CM. Patients who completed ATTR-ACT were eligible to enroll in an ongoing long-term extension study (LTE) which provides additional data on the long-term efficacy of tafamidis.

Purpose

To assess the long-term benefit of tafamidis in patients with ATTR-CM and to determine median survival times with treatment.

Methods

Patients with ATTR-CM who completed ATTR-ACT (in which they were randomized to tafamidis meglumine 80 mg, 20 mg or placebo for 30 months) could enroll in the ongoing LTE in which patients continued to be treated with the same dose of tafamidis or, if previously treated with placebo, were randomized to tafamidis meglumine 80 mg or 20 mg. Tafamidis free acid 61 mg is a new formulation (bioequivalent to tafamidis meglumine 80 mg) developed for patient convenience and all patients in the LTE transitioned to tafamidis free acid 61 mg as of 1 Aug, 2018. All-cause mortality (with heart transplant or cardiac mechanical assist device [CMAD] implantation counted as death) was assessed using a Cox proportional hazards model (as of 1 Aug, 2019). Patients treated with tafamidis meglumine 80 mg in ATTR-ACT and the LTE who transitioned to tafamidis free acid 61 mg (tafamidis 80/61 mg) were compared with patients treated with placebo in ATTR-ACT who transitioned to tafamidis in the LTE (placebo/tafamidis).

Results

There were a total of 176 tafamidis 80/61 mg patients and 177 placebo/tafamidis patients. Median treatment duration was 51.9 months with tafamidis 80/61 mg and 51.4 months with placebo/tafamidis. With tafamidis 80/61 mg, there were 75 (42.6%) all-cause deaths; consisting of 67 (38.1%) deaths, 6 (3.4%) heart transplants, and 2 (1.1%) CMAD implantations. With placebo/tafamidis, there were 108 (61.0%) all-cause deaths; consisting of 102 (57.6%) deaths and 6 (3.4%) heart transplants. There was a significant reduction of 41.1% in the risk of all-cause mortality with tafamidis 80/61 mg compared with placebo/tafamidis (hazard ratio [95% CI], 0.5888 [0.4370, 0.7931]; P=0.0004). Median survival time with placebo/tafamidis was 35.8 months but was not reached with tafamidis 80/61 mg.

Conclusions

Treatment with tafamidis significantly improves long-term survival in patients with ATTR-CM. The comparatively poorer survival in patients treated with placebo in ATTR-ACT who transitioned to tafamidis in the LTE highlights the importance of early diagnosis and treatment.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): This study was sponsored by Pfizer.

Efficacy and safety of tafamidis doses in the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT) and long-term extension study

Aims

Tafamidis is an effective treatment for transthyretin amyloid cardiomyopathy (ATTR‐CM) in the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR‐ACT). While ATTR‐ACT was not designed for a dose‐specific assessment, further analysis from ATTR‐ACT and its long‐term extension study (LTE) can guide determination of the optimal dose.

Methods and results

In ATTR‐ACT, patients were randomized (2:1:2) to tafamidis 80 mg, 20 mg, or placebo for 30 months. Patients completing ATTR‐ACT could enrol in the LTE (with placebo‐treated patients randomized to tafamidis 80 or 20 mg; 2:1) and all patients were subsequently switched to high‐dose tafamidis. All‐cause mortality was assessed in ATTR‐ACT combined with the LTE (median follow‐up 51 months). In ATTR‐ACT, the combination of all‐cause mortality and cardiovascular‐related hospitalizations over 30 months was significantly reduced with tafamidis 80 mg (P = 0.0030) and 20 mg (P = 0.0048) vs. placebo. All‐cause mortality vs. placebo was reduced with tafamidis 80 mg [Cox hazards model (95% confidence interval): 0.690 (0.487–0.979), P = 0.0378] and 20 mg [0.715 (0.450–1.137), P = 0.1564]. The mean (standard error) change in N‐terminal pro‐B‐type natriuretic peptide from baseline to Month 30 was −1170.51 (587.31) (P = 0.0468) with tafamidis 80 vs. 20 mg. In ATTR‐ACT combined with the LTE there was a significantly greater survival benefit with tafamidis 80 vs. 20 mg [0.700 (0.501–0.979), P = 0.0374]. Incidence of adverse events in both tafamidis doses were comparable to placebo.

Conclusion

Tafamidis, both 80 and 20 mg, effectively reduced mortality and cardiovascular‐related hospitalizations in patients with ATTR‐CM. The longer‐term survival data and the lack of dose‐related safety concerns support tafamidis 80 mg as the optimal dose.

Clinical Trial Registration: ClinicalTrials.gov NCT01994889; NCT02791230.

Benefits of tafamidis in patients with advanced transthyretin amyloid cardiomyopathy

Background

In the Tafamidis in Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), tafamidis was shown to be an effective treatment for patients with transthyretin amyloid cardiomyopathy (ATTR-CM). Further assessment of the efficacy of tafamidis in patients with more advanced ATTR-CM would aid treatment decisions.

Purpose

To characterize the benefits of tafamidis in patients with advanced ATTR-CM.

Methods

In ATTR-ACT, ATTR-CM patients were randomized to tafamidis (n=264) or placebo (n=177) for 30 months. Efficacy outcomes included all-cause mortality and frequency of cardiovascular (CV)-related hospitalisations. Key secondary endpoints were change from baseline to Month 30 in 6MWT distance and KCCQ-OS score. Efficacy assessments in NYHA Class III patients at baseline (n=141) were a pre-specified analysis. In a post-hoc analysis, mortality and CV-related hospitalizations were assessed in all patients grouped into quartiles of increasing disease severity based on 6MWT distance at baseline. Longer-term all-cause mortality (as of 1 Aug 2019) was assessed in NYHA Class III patients utilizing data from ATTR-ACT patients who enrolled in a long-term, extension study (LTE) and continued treatment with higher dose tafamidis (n=55; median treatment duration 51.6 months); or, if previously treated with placebo, started tafamidis treatment (placebo/tafamidis; n=63 [50.1 months]).

Results

In advanced ATTR-CM patients (NYHA Class III), tafamidis reduced the risk of death (HR [95% CI] 0.837, [0.541, 1.295], P=0.4253), and the decline in 6MWT distance (LS mean [SE], 31.6 (22.1) m; P=0.1526) and KCCQ-OS score (LS mean [SE], 13.1 (5.0); P=0.0090), vs placebo. Paradoxically, there was a higher frequency of CV-related hospitalizations with tafamidis (RR [95% CI] vs placebo, 1.411 [1.048, 1.900]). In all patients by 6MWT quartile, CV-related hospitalizations/year with tafamidis and placebo increased with disease severity, with the exception that placebo-treated patients in the highest severity quartile had fewer CV-related hospitalisations (0.73) than those in the third quartile (0.92). Mortality with tafamidis and placebo increased, and was greater with placebo, in every quartile (Figure). Survival (NYHA Class III patients in ATTR-ACT and LTE) was improved with high dose tafamidis with longer term follow-up (HR vs placebo/tafamidis [95% CI], 0.6569 [0.4175, 1.0336]; P=0.0692).

Conclusions

These analyses, including longer-term follow-up, demonstrate that patients with advanced ATTR-CM benefit from tafamidis. The decrease in CV-related hospitalisations in more severe patients treated with placebo suggests that the comparatively greater hospitalisation frequency in NYHA Class III patients treated with tafamidis is a consequence of their lower mortality rate.

Figure 1

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): This study was sponsored by Pfizer

A comprehensive safety profile of tafamidis in patients with transthyretin amyloid polyneuropathy

Background: Tafamidis is approved in over 40 countries to delay neurologic progression in patients with transthyretin amyloid polyneuropathy (ATTR-PN). A comprehensive, integrated analysis of safety data from interventional, observational and surveillance studies of tafamidis in ATTR-PN patients was conducted. Methods: Safety data from all sponsored, completed, or ongoing, Phase 2/3 studies of tafamidis in ATTR-PN patients as of 3 January 2017 were pooled. Also assessed were safety data from the ongoing Transthyretin Amyloidosis Outcomes Survey (THAOS) as of 3 January 2017 and post-marketing surveillance reports as of 31 March 2017. Results: There were 137 patients in Phase 2/3 studies (mean duration of tafamidis exposure, 44.2 months), with 134 (97.8%) experiencing ≥1 treatment-emergent adverse event (TEAE) and 46 (33.6%) ≥1 treatment-emergent serious adverse event (TESAE). The most common TEAEs were diarrhoea (26.3%), urinary tract infection (UTI; 25.5%) and influenza (21.2%). In THAOS, 661 subjects had tafamidis exposure (mean duration, 27.6 months), with 250 (37.8%) experiencing ≥1 TEAE and 96 (14.5%) ≥1 TESAE. The most common TEAE was UTI (6.1%). Post-marketing surveillance reports generally reflected the known safety profile of tafamidis. Conclusions: This analysis did not reveal any significant new safety findings; tafamidis was generally safe and well tolerated in ATTR-PN patients. ClinicalTrials.gov: NCT00409175, NCT00791492, NCT00630864, NCT01435655, NCT00925002, and NCT00628745.

1169Interim analysis of data from a long-term, extension trial of tafamidis meglumine in patients with transthyretin amyloid cardiomyopathy

Background

Transthyretin amyloid cardiomyopathy (ATTR-CM), is an underdiagnosed, fatal disease caused by the deposition of transthyretin amyloid fibrils in the heart leading to heart failure. The Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), an international, multi-center, double-blind, placebo-controlled, randomized study, demonstrated the efficacy and safety of tafamidis treatment for patients with ATTR-CM due to variant (ATTRm) or wild-type (ATTRwt) TTR.

Purpose

This is a pooled analysis of data from ATTR-ACT and interim data from the ongoing, long-term, extension study to evaluate longer term data on the efficacy of tafamidis in patients with ATTR-CM.

Methods

Patients who completed ATTR-ACT (which had a duration of 30 months) were eligible to be enrolled in a long-term, extension study in which patients either continued to receive tafamidis meglumine at the same dose (the tafamidis/tafamidis [T/T] group) or, for patients previously treated with placebo, were randomised (in a 1:2 ratio) to tafamidis meglumine 20 mg or 80 mg (the placebo/tafamidis [P/T] group) for up to 60 months. The primary efficacy outcome was all-cause mortality. This analysis combined data from the completed ATTR-ACT with interim data from the extension study (cut-off date: 15 Feb, 2018), and included patients treated with tafamidis meglumine across the two studies with a median follow up of 36 months.

Results

All-cause mortality was significantly lower in the T/T group (n=264; 88 events, 33.3%) compared with the P/T group (n=177; 88 events, 50.3%); hazard ratio (95% CI), 0.64 (0.47, 0.85); P=0.001. In the subgroup of ATTRwt patients, all-cause mortality was significantly reduced in the T/T group (55/201; 27.4%) compared with the P/T group (60/134; 44.8%); 0.64 (0.44, 0.92); P=0.002. In the 106 (24.0%) ATTRm patients, there was a trend towards a reduction in all-cause mortality in the T/T group (33/63; 52.4%) compared with the P/T group (29/43; 67.4%); 0.66 (0.39, 1.09); P=0.17. In patients who were NYHA Class I or II at baseline, all-cause mortality was significantly reduced in the T/T group (38/186; 20.4%) compared with the P/T group (45/114; 39.5%); 0.49 (0.32, 0.75); P=0.001. In those patients with more severe symptoms at baseline (NYHA Class III), there were fewer deaths in the T/T group (50/78; 64.1%) compared with the P/T group (44/63; 69.8%); 0.80 (0.53, 1.21), but this difference was not statistically significant (P=0.50).

Conclusions

In ATTR-ACT, tafamidis was shown to significantly improve survival, functional capacity, and quality of life in patients with ATTR-CM. This pooled analysis with data from the ongoing extension study further supports the efficacy of tafamidis in patients over a longer period of time and the importance of early diagnosis and treatment.

Acknowledgement/Funding

This study was sponsored by Pfizer.

Tafamidis Treatment for Patients with Transthyretin Amyloid Cardiomyopathy

BACKGROUND

Transthyretin amyloid cardiomyopathy is caused by the deposition of transthyretin amyloid fibrils in the myocardium. The deposition occurs when wild-type or variant transthyretin becomes unstable and misfolds. Tafamidis binds to transthyretin, preventing tetramer dissociation and amyloidogenesis.

METHODS

In a multicenter, international, double-blind, placebo-controlled, phase 3 trial, we randomly assigned 441 patients with transthyretin amyloid cardiomyopathy in a 2:1:2 ratio to receive 80 mg of tafamidis, 20 mg of tafamidis, or placebo for 30 months. In the primary analysis, we hierarchically assessed all-cause mortality, followed by frequency of cardiovascular-related hospitalizations according to the Finkelstein-Schoenfeld method. Key secondary end points were the change from baseline to month 30 for the 6-minute walk test and the score on the Kansas City Cardiomyopathy Questionnaire-Overall Summary (KCCQ-OS), in which higher scores indicate better health status.

RESULTS

In the primary analysis, all-cause mortality and rates of cardiovascular-related hospitalizations were lower among the 264 patients who received tafamidis than among the 177 patients who received placebo (P<0.001). Tafamidis was associated with lower all-cause mortality than placebo (78 of 264 [29.5%] vs. 76 of 177 [42.9%]; hazard ratio, 0.70; 95% confidence interval [CI], 0.51 to 0.96) and a lower rate of cardiovascular-related hospitalizations, with a relative risk ratio of 0.68 (0.48 per year vs. 0.70 per year; 95% CI, 0.56 to 0.81). At month 30, tafamidis was also associated with a lower rate of decline in distance for the 6-minute walk test (P<0.001) and a lower rate of decline in KCCQ-OS score (P<0.001). The incidence and types of adverse events were similar in the two groups.

CONCLUSIONS

In patients with transthyretin amyloid cardiomyopathy, tafamidis was associated with reductions in all-cause mortality and cardiovascular-related hospitalizations and reduced the decline in functional capacity and quality of life as compared with placebo. (Funded by Pfizer; ATTR-ACT ClinicalTrials.gov number, NCT01994889 .).

Treatment With Tafamidis Slows Disease Progression in Early-Stage Transthyretin Cardiomyopathy

Background:

Transthyretin cardiomyopathy (TTR-CM) is a progressive, fatal disease caused by the accumulation of misfolded transthyretin (TTR) amyloid fibrils in the heart. Tafamidis is a kinetic stabilizer of TTR that inhibits misfolding and amyloid formation.

Methods:

In this post hoc analysis, data from an observational study (Transthyretin Amyloidosis Cardiac Study; n = 29) were compared with an open-label study of tafamidis in patients with TTR-CM (Fx1B-201; n = 35). To ensure comparable baseline disease severity, patients with New York Heart Association (NYHA) functional classification ≥III were excluded in this time-to-mortality analysis.

Results:

Patients with either wild-type or Val122Ile genotypes treated with tafamidis have a significantly longer time to death compared with untreated patients (P = .0004). Similar results were obtained when limiting the analysis to wild-type patients only, without restricting NYHA functional classification (P = .0262).

Conclusions:

These results support earlier conclusions suggesting that tafamidis slows disease progression compared with no treatment outside of standard of care and warrant further investigation.

Trial Registration:

ClinicalTrials.gov, NCT00694161.

Design and Rationale of the Phase 3 ATTR-ACT Clinical Trial (Tafamidis in Transthyretin Cardiomyopathy Clinical Trial)

Transthyretin amyloidosis is a rare, life-threatening disease resulting from aggregation and deposition of transthyretin amyloid fibrils in various tissues. There are 2 predominate phenotypic presentations of the disease: transthyretin familial amyloid polyneuropathy, which primarily affects the peripheral nerves, and transthyretin cardiomyopathy (TTR-CM), which primarily affects the heart. However, there is a wide overlap with symptoms at presentation and disease course being highly variable and influenced by the underlying transthyretin mutation, age of the affected individual, sex, and geographic location. Treatment of transthyretin amyloidosis is typically focused on symptom management. Although tafamidis has been shown to delay neurologic progression of transthyretin familial amyloid polyneuropathy, there are no approved pharmacologic therapies shown to improve survival in TTR-CM. The natural history of TTR-CM is poorly characterized, which presents difficulties for the design of large-scale trials for new treatments. This review provides a brief overview of TTR-CM and the challenges of identifying clinically meaningful end points and study parameters to determine the efficacy of treatments for rare diseases. The design and rationale behind the ongoing phase 3 ATTR-ACT study (Tafamidis in Transthyretin Cardiomyopathy Clinical Trial), an international, multicenter, double-blind, placebo-controlled, randomized clinical trial, is also outlined. The ATTR-ACT study will provide important insight into the efficacy and safety of tafamidis for the treatment of TTR-CM.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01994889.

Tafamidis delays disease progression in patients with early stage transthyretin familial amyloid polyneuropathy: additional supportive analyses from the pivotal trial

BACKGROUND

Tafamidis, a non-NSAID highly specific transthyretin stabilizer, delayed neurologic disease progression as measured by Neuropathy Impairment Score-Lower Limbs (NIS-LL) in an 18-month, double-blind, placebo-controlled randomized trial in 128 patients with early-stage transthyretin V30M familial amyloid polyneuropathy (ATTRV30M-FAP). The current post hoc analyses aimed to further evaluate the effects of tafamidis in delaying ATTRV30M-FAP progression in this trial.

METHODS

Pre-specified, repeated-measures analysis of change from baseline in NIS-LL in this trial (ClinicalTrials.gov NCT00409175) was repeated with addition of baseline as covariate and multiple imputation analysis for missing data by treatment group. Change in NIS-LL plus three small-fiber nerve tests (NIS-LL + Σ3) and NIS-LL plus seven nerve tests (NIS-LL + Σ7) were assessed without baseline as covariate. Treatment outcomes over the NIS-LL, Σ3, Σ7, modified body mass index and Norfolk Quality of Life-Diabetic Neuropathy Total Quality of Life Score were also examined using multivariate analysis techniques.

RESULTS

Neuropathy progression based on NIS-LL change from baseline to Month 18 remained significantly reduced for tafamidis versus placebo in the baseline-adjusted and multiple imputation analyses. NIS-LL + Σ3 and NIS-LL + Σ7 captured significant treatment group differences. Multivariate analyses provided strong statistical evidence for a superior tafamidis treatment effect.

CONCLUSIONS

These supportive analyses confirm that tafamidis delays neurologic progression in early-stage ATTRV30M-FAP.

TRIAL REGISTRATION NUMBER

NCT00409175.

Early intervention with tafamidis provides long-term (5.5-year) delay of neurologic progression in transthyretin hereditary amyloid polyneuropathy

Transthyretin hereditary amyloid polyneuropathy, also traditionally known as transthyretin familial amyloid polyneuropathy (ATTR-FAP), is a rare, relentless, fatal hereditary disorder. Tafamidis, an oral, non-NSAID, highly specific transthyretin stabilizer, demonstrated safety and efficacy in slowing neuropathy progression in early-stage ATTRV30M-FAP in a 1.5-year, randomized, double-blind, placebo-controlled trial, and 1-year open-label extension study, with a second long-term open-label extension study ongoing. Subgroup analysis of the effectiveness of tafamidis in the pivotal study and its open-label extensions revealed a relatively cohesive cohort of patients with mild neuropathy (i.e. Neuropathy Impairment Score for Lower Limbs [NIS-LL] ≤ 10) at the start of active treatment. Early treatment with tafamidis for up to 5.5 years (≥1 dose of tafamidis meglumine 20 mg once daily during the original trial or after switching from placebo in its extension) resulted in sustained delay in neurologic progression and long-term preservation of nutritional status in this cohort. Mean (95% CI) changes from baseline in NIS-LL and mBMI were 5.3 (1.6, 9.1) points and -7.8 (-44.3, 28.8) kg/m² × g/L at 5.5 years, respectively. No new safety issues or side effects were identified. These data represent the longest prospective evaluation of tafamidis to date, confirm a favorable safety profile, and underscore the long-term benefits of early intervention with tafamidis.

TRIAL REGISTRATION

ClincalTrials.gov Identifier: NCT00409175, NCT00791492, and NCT00925002.