Dataset Information

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

ABSTRACT:

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.

SUBMITTER: Elliott P

PROVIDER: S-EPMC8763250 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundIn patients with transthyretin amyloid cardiomyopathy, tafamidis reduces all-cause mortality and cardiovascular hospitalizations and slows decline in quality of life compared with placebo. In May 2019, tafamidis received expedited approval from the US Food and Drug Administration as a breakthrough drug for a rare disease. However, at $225 000 per year, it is the most expensive cardiovascular drug ever launched in the United States, and its long-term cost-effectiveness and budget impact are uncertain. We therefore aimed to estimate the cost-effectiveness of tafamidis and its potential effect on US health care spending.MethodsWe developed a Markov model of patients with wild-type or variant transthyretin amyloid cardiomyopathy and heart failure (mean age, 74.5 years) using inputs from the ATTR-ACT trial (Transthyretin Amyloidosis Cardiomyopathy Clinical Trial), published literature, US Food and Drug Administration review documents, healthcare claims, and national survey data. We compared no disease-specific treatment ("usual care") with tafamidis therapy. The model reproduced 30-month survival, quality of life, and cardiovascular hospitalization rates observed in ATTR-ACT; future projections used a parametric survival model in the control arm, with constant hazards reduction in the tafamidis arm. We discounted future costs and quality-adjusted life-years by 3% annually and examined key parameter uncertainty using deterministic and probabilistic sensitivity analyses. The main outcomes were lifetime incremental cost-effectiveness ratio and annual budget impact, assessed from the US healthcare sector perspective. This study was independent of the ATTR-ACT trial sponsor.ResultsCompared with usual care, tafamidis was projected to add 1.29 (95% uncertainty interval, 0.47-1.75) quality-adjusted life-years at an incremental cost of $1 135 000 (872 000-1 377 000), resulting in an incremental cost-effectiveness ratio of $880 000 (697 000-1 564 000) per quality-adjusted life-year gained. Assuming a threshold of $100 000 per quality-adjusted life-year gained and current drug price, tafamidis was cost-effective in 0% of 10 000 probabilistic simulations. A 92.6% price reduction from $225 000 to $16 563 would be necessary to make tafamidis cost-effective at $100 000/quality-adjusted life-year. Results were sensitive to assumptions related to long-term effectiveness of tafamidis. Treating all eligible patients with transthyretin amyloid cardiomyopathy in the United States with tafamidis (n=120 000) was estimated to increase annual healthcare spending by $32.3 billion.ConclusionsTreatment with tafamidis is projected to produce substantial clinical benefit but would greatly exceed conventional cost-effectiveness thresholds at the current US list price. On the basis of recent US experience with high-cost cardiovascular medications, access to and uptake of this effective therapy may be limited unless there is a large reduction in drug costs.

Project description:AimsTafamidis treatment positively affects left ventricular (LV) structure and function and improves outcomes in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). We aimed to investigate the relationship between treatment response and cardiac amyloid burden identified by serial quantitative 99mTc-DPD SPECT/CT. We furthermore aimed to identify nuclear imaging biomarkers that could be used to quantify and monitor response to tafamidis therapy.Methods and resultsForty wild-type ATTR-CM patients who underwent 99mTc-DPD scintigraphy and SPECT/CT imaging at baseline and after treatment with tafamidis 61 mg once daily [median, 9.0 months (interquartile range 7.0-10.0)] were divided into two cohorts based on the median (-32.3%) of the longitudinal percent change in standardized uptake value (SUV) retention index. ATTR-CM patients with a reduction greater than or equal to the median (n = 20) had a significant decrease in SUV retention index (P < 0.001) at follow-up, which translated into significant benefits in serum N-terminal prohormone of brain natriuretic peptide levels (P = 0.006), left atrial volume index (P = 0.038), as well as LV [LV global longitudinal strain: P = 0.028, LV ejection fraction (EF): P = 0.027, LV cardiac index (CI): P = 0.034] and right ventricular (RV) [RVEF: P = 0.025, RVCI: P = 0.048] functions compared with patients with a decrease less than the median (n = 20).ConclusionTreatment with tafamidis in ATTR-CM patients results in a significant reduction in SUV retention index, associated with significant benefits for LV and RV function and cardiac biomarkers. Serial quantitative 99mTc-DPD SPECT/CT imaging with SUV may be a valid tool to quantify and monitor response to tafamidis treatment in affected patients.Translational perspective99mTc-DPD SPECT/CT imaging with determination of SUV retention index as part of a routine annual examination can provide evidence of treatment response in ATTR-CM patients receiving disease-modifying therapy. Further long-term studies with 99mTc-DPD SPECT/CT imaging may help to evaluate the relationship between tafamidis-induced reduction in SUV retention index and outcome in patients with ATTR-CM and will demonstrate whether highly disease-specific 99mTc-DPD SPECT/CT imaging is more sensitive than routine diagnostic monitoring.