Disease-Modifying Advances in ATTR-CM Management

For years, disease modification in the treatment of transthyretin amyloid cardiomyopathy (ATTR-CM) was limited at best, with management focused primarily on symptom control. Median survival without treatment has been reported to be approximately 2-5 years.

In their 2025 review in Cardiology and Therapy, Margolin and colleagues describe how this landscape has changed, with multiple disease-modifying agents now targeting distinct stages of the transthyretin (TTR) pathogenic cascade. The authors note that the number of FDA approvals for ATTR-CM tripled within a six-month period.

Pathophysiologic Basis for Therapy

ATTR-CM results from myocardial deposition of misfolded TTR fibrils. Disease may arise from wild-type TTR, typically associated with aging, or from inherited TTR variants transmitted in an autosomal dominant pattern with incomplete penetrance. Tetramer destabilization allows dissociation into monomers, which misfold and aggregate into amyloid fibrils that deposit extracellularly in the myocardium. Progressive ventricular wall thickening and impaired relaxation lead to heart failure.

This mechanistic framework has guided drug development. Current and investigational therapies fall into three broad categories:

• Stabilizers, which prevent tetramer dissociation;
• Silencers, which reduce hepatic TTR production; and
• Depleters, which bind amyloid and promote immune-mediated clearance.

TTR Stabilization

Approved in 2019, tafamidis was the first therapy shown to reduce mortality in ATTR-CM. In the ATTR-ACT trial, tafamidis reduced all-cause mortality over 30 months (29.5% vs 42.9% with placebo; hazard ratio [HR] 0.67) and lowered cardiovascular-related hospitalizations by 32%. Functional decline was attenuated, with slower reductions in six-minute walk distance (6MWT) and Kansas City Cardiomyopathy Questionnaire Overall Summary (KCCQ-OS) scores.

Acoramidis, approved in November 2024, was engineered to mimic the stabilizing T119M TTR variant. In the ATTRibute-CM trial, it met a hierarchical composite endpoint incorporating all-cause mortality, cardiovascular hospitalizations, NT-proBNP change, and 6MWT, with a win ratio of 1.8. In a cardiac magnetic resonance sub-study, trends in extracellular parameters suggested the possibility of amyloid regression; the authors emphasize that this finding requires further investigation. Cross-trial comparisons between stabilizers remain limited by differences in design and enrolled populations.

TTR Silencing

RNA-based therapies that reduce TTR production have progressed in parallel. Patisiran, an intravenously administered small interfering RNA previously approved for hereditary ATTR polyneuropathy, improved 6MWT and quality-of-life measures in the APOLLO-B trial. However, it did not demonstrate statistically significant differences in composite clinical outcomes, and the study was not powered for those endpoints. In October 2023, the FDA declined to extend its label to ATTR-CM, citing modest absolute benefit and reliance on surrogate endpoints.

Vutrisiran, a second-generation subcutaneous RNA interference therapy, received FDA approval for ATTR-CM in March 2025 following the HELIOS-B trial. Vutrisiran reduced the composite of all-cause mortality and recurrent cardiovascular events (HR 0.72) and attenuated functional decline, including a 26.5-meter smaller reduction in 6MWT and a 5.8-point smaller decline in KCCQ-OS compared with placebo.

Other silencers under investigation include the antisense oligonucleotide eplontersen and next-generation RNA interference constructs such as nucresiran. Gene-editing approaches have also entered early-phase evaluation. Nexiguran ziclumeran (NTLA-2001), a CRISPR–Cas9–based therapy, achieved mean TTR reductions of approximately 89% one month after treatment in a phase 1 study, with reductions sustained at 12 months in reported follow-up.

Amyloid Depletion

Monoclonal antibodies designed to bind amyloid and promote immune-mediated clearance are currently in phase 2 and 3 trials. Agents such as ALXN2220 and coramitug target deposited fibrils rather than upstream TTR production. Early-phase studies have demonstrated improvements in imaging parameters and biomarkers, while larger trials are evaluating effects on mortality and structural remodeling.

Supportive Care and Monitoring

Despite advances in disease modification, supportive care remains central. Diuretics are the cornerstone of heart failure management. Observational data suggest possible survival benefit from low-dose beta-blockers in patients with reduced ejection fraction (≤40%), although other cohorts have reported improved quality of life after withdrawal. Vasodilators may worsen hypotension, particularly in patients with autonomic dysfunction. Mineralocorticoid receptor antagonists and sodium-glucose cotransporter-2 inhibitors appear better tolerated, though prospective ATTR-CM–specific data remain limited.

Atrial fibrillation is common, and anticoagulation is recommended irrespective of CHA₂DS₂-VASc score because of elevated thromboembolic risk. Device therapy and advanced heart failure interventions retain defined roles; contemporary series report three-year survival after heart transplantation approaching 90% in carefully selected patients.

Monitoring strategies integrate clinical endpoints, biomarkers, and imaging. NT-proBNP increases exceeding 30% or 700 ng/L, declines in 6MWT greater than 35 meters, outpatient diuretic escalation, and worsening global longitudinal strain are associated with adverse prognosis. Staging systems from the Mayo Clinic and the UK National Amyloidosis Centre incorporate NT-proBNP, troponin, and renal function. Cardiac magnetic resonance-derived extracellular volume provides a surrogate of amyloid burden, though cost and access limit serial use.

Cost and Unresolved Questions

Annual costs are reported at approximately $240,000 for stabilizers and more than $500,000 for silencers. Cost-effectiveness analyses have estimated incremental cost-effectiveness ratios exceeding $180,000 per quality-adjusted life year, suggesting that price reductions of 80-92% would be required to meet conventional value thresholds.

Evidence to guide sequencing or combination therapy remains limited. Although some trials permitted background tafamidis use, they were not powered to compare monotherapy with combination strategies. Expert consensus therefore continues to endorse monotherapy as the standard approach pending more definitive comparative data.

Margolin and colleagues describe a field in transition, in which mechanistic insight has translated into multiple targeted therapies. At the same time, optimal sequencing, long-term durability, and economic sustainability remain areas of ongoing investigation.

Reference:
Margolin E, Stern LK, Argiro A, et al. Current and future treatment landscape of transthyretin amyloid cardiomyopathy. Cardiol Ther. 2025;14:385-401. doi:10.1007/s40119-025-00424-6