ATTR-CM Symptoms and Hospitalizations Improve With Acoramidis

Health status declined less with acoramidis

In the randomized ATTRibute-CM trial, acoramidis produced a clinically meaningful advantage over placebo in Kansas City Cardiomyopathy Questionnaire Overall Summary Score, or KCCQ-OS, at 30 months. The adjusted between-group difference was 9.94 points (95% CI, 5.97 to 13.91; P<0.001), favoring acoramidis.

That difference matters because the KCCQ captures aspects of heart failure that mortality and hospitalization counts cannot: symptom frequency and burden, physical limitations, social limitations, quality of life and self-efficacy. Scores range from 0 to 100, with higher values indicating better health status. A difference of about 5 points is commonly considered clinically meaningful at the individual level, although group averages do not show how every participant responded.

The dedicated health-status analysis adds detail to the pivotal efficacy findings. Across follow-up, the patient-reported results were consistent with less deterioration among participants assigned to acoramidis, rather than merely a statistical separation at the final visit. This is relevant in transthyretin amyloid cardiomyopathy, or ATTR-CM, because progressive fatigue, exertional intolerance, edema and restrictions in ordinary activity can dominate patients’ experience even before terminal events occur.

Cardiovascular hospitalization findings pointed in the same direction. Over 30 months, 26.7% of participants assigned to acoramidis and 42.6% assigned to placebo had a cardiovascular-related hospitalization. The pivotal trial’s hierarchical primary analysis, which incorporated all-cause mortality and cardiovascular hospitalization, yielded a win ratio of 1.8 (95% CI, 1.4 to 2.2; P<0.001) in favor of acoramidis.

How the randomized evidence was generated

ATTRibute-CM was a phase 3, double-blind, placebo-controlled trial that randomized 632 adults with symptomatic ATTR-CM in a 2:1 ratio to oral acoramidis or placebo. The primary efficacy analysis included 611 participants. Treatment continued for 30 months, providing substantially longer observation than a short symptom study and allowing hospitalization differences to emerge alongside changes in functional status.

Participants had either wild-type or variant transthyretin disease and clinical heart failure attributable to cardiac amyloid deposition. The study population was predominantly older and male, reflecting diagnosed ATTR-CM populations but also limiting certainty about effects in women, younger adults and demographic groups that were less well represented.

Acoramidis is a transthyretin stabilizer. By binding transthyretin, it is intended to inhibit dissociation of the native tetramer, an early step in the cascade leading to amyloid formation. The randomized comparison therefore assessed a disease-modifying strategy rather than a conventional diuretic or another treatment aimed only at relieving congestion.

The health-status evidence should be interpreted within the larger trial rather than in isolation. KCCQ-OS was a prespecified efficacy outcome, and randomization supports a causal interpretation of the between-group difference under the trial conditions. The concordance of patient-reported health status, walking performance and cardiovascular hospitalization strengthens the internal consistency of the result.

The FDA subsequently approved acoramidis (Attruby) for adults with wild-type or variant ATTR-CM to reduce cardiovascular death and cardiovascular-related hospitalization. Approval establishes that the regulator judged the total efficacy and safety evidence sufficient for that indication; it does not mean that every treated patient will experience symptom improvement or avoid hospitalization.

Why patient-reported benefit changes the treatment discussion

Hospitalization prevention has an obvious clinical and health-system value. Admissions for decompensated heart failure can accelerate functional decline, disrupt caregiving and generate substantial costs. A lower cardiovascular hospitalization burden therefore supports acoramidis as a disease-modifying option with consequences beyond a biomarker or imaging change.

The KCCQ result answers a different bedside question: whether patients are likely to feel or function better, or at least decline more slowly. ATTR-CM often progresses despite careful volume management, and treatment goals may include preserving independence, walking capacity and participation in daily life. A nearly 10-point adjusted advantage over placebo at 30 months is large enough to be noticeable at the population level and exceeds the conventional threshold for clinical importance.

Still, the average treatment effect should not be translated into a promise for an individual. Some participants will improve, some will remain stable and others will decline despite therapy. Baseline disease stage, competing illnesses, frailty, treatment adherence and the timing of diagnosis may all influence the outcome experienced in practice.

Treatment selection also requires comparison with other available transthyretin-directed therapies, but ATTRibute-CM did not randomize participants between active agents. The trial can establish acoramidis’s benefit over placebo; it cannot establish superiority or equivalence to another stabilizer or a transthyretin-silencing therapy. Cross-trial comparisons are especially uncertain because eligibility criteria, disease severity, background treatment and outcome definitions differ.

Limits and unanswered questions

The trial’s 30-month duration is a strength, but ATTR-CM is lifelong and progressive. Longer follow-up is needed to define durability, late safety outcomes and whether early health-status preservation translates into a sustained survival advantage. Evidence is also more limited for patients with very advanced disease, severe kidney dysfunction or clinical characteristics excluded or underrepresented in the trial.

KCCQ is validated in heart failure, but it is self-reported and can be affected by noncardiac illness, expectations and missing assessments among people who become too ill to participate. Death can also complicate interpretation because patients who die no longer provide questionnaire data. Analytic methods can reduce, but not eliminate, these challenges.

The pivotal program was sponsored by Eidos Therapeutics, a BridgeBio company, and investigators reported financial relationships. Sponsorship does not invalidate a randomized result, but independent replication, transparent reporting and postmarketing evidence remain important. The study was not designed for direct head-to-head comparisons with other approved ATTR-CM treatments or for definitive estimates within small genetic and demographic subgroups.

Questions clinicians ask

Is the KCCQ difference likely to be noticeable to patients?

Yes at the group level. The adjusted 9.94-point advantage exceeded the approximately 5-point difference generally regarded as clinically meaningful, suggesting better preservation of symptoms, function and quality of life. Individual responses will vary, so serial patient-reported measures can complement examination findings and hospitalization history.

Does the trial show that acoramidis prevents heart failure admissions?

It shows that assignment to acoramidis reduced cardiovascular hospitalization outcomes relative to placebo over 30 months under randomized trial conditions. Cardiovascular hospitalization occurred in 26.7% of the acoramidis group and 42.6% of the placebo group, but the treatment does not eliminate admission risk.

Can these results identify the best transthyretin-directed therapy?

No. ATTRibute-CM compared acoramidis with placebo, not with another stabilizer or a transthyretin-silencing agent. Decisions among active therapies therefore require consideration of regulatory indications, safety, administration, access, comorbidities and the limits of indirect cross-trial comparisons.

Which patients are least represented by this evidence?

Certainty is lower for women, younger adults, people with very advanced heart failure or severe kidney dysfunction, and smaller variant-specific subgroups. The trial supports treatment in adults resembling its population, but broader postmarketing and real-world data are needed to clarify effectiveness across the full ATTR-CM population.

References

1. Effect of Acoramidis on Heart Failure–Related Health Status — PubMed Central, 2026
2. Efficacy and Safety of Acoramidis in Transthyretin Amyloid Cardiomyopathy — New England Journal of Medicine, 2024
3. A Study to Evaluate the Efficacy and Safety of Acoramidis in Participants With Transthyretin Amyloid Cardiomyopathy — ClinicalTrials.gov, 2024
4. ATTRUBY (acoramidis) Prescribing Information — US Food and Drug Administration, 2024