BridgeBio's Attruby shows evidence of disease reversal in long-term heart study

BridgeBio Pharma (BBIO) has presented new analyses from its phase 3 ATTRibute-CM study of Attruby (acoramidis) in transthyretin amyloid cardiomyopathy, including the first evidence from serial cardiac magnetic resonance imaging that a therapy may be capable of reversing disease progression, at the European Society of Cardiology Congress 2026.

In a completer analysis of the CMR substudy, clinically meaningful improvement in left ventricular systolic function was observed in 54 per cent of acoramidis-treated patients versus 20 per cent of those on placebo at Month 30, with 53 per cent of patients on continuous acoramidis sustaining that improvement at Month 42. By comparison, only 26 per cent of patients in an independent natural history cohort showed improved LV systolic function by Month 24, suggesting the gains observed with acoramidis fall outside the expected course of the disease.

In a more conservative analysis, long-term treatment was associated with clinically meaningful LV systolic improvement in approximately one-third of patients over 30 to 42 months — 34 per cent of acoramidis-treated patients versus 9 per cent of placebo patients at Month 30. Additionally, 46 per cent of patients receiving continuous acoramidis showed improvement in LV mass index at Month 42, indicating favorable structural remodeling of the heart.

A post-hoc analysis examined days lost to death and cardiovascular-related hospitalization, a patient-centered composite measure. Acoramidis reduced the estimated mean percentage of such days to 7.5 per cent versus 11.7 per cent with placebo through Month 30, preserving more than 38 additional days alive and out of hospital over that period. That benefit nearly doubled to 65 days over three years in observed data, and modeled estimates suggest it could approach 94 days — reflecting a progressive divergence in outcomes over time.

Data from the open-label extension through Month 54 in 56 variant ATTR-CM patients showed all-cause mortality of 30.4 per cent with continuous acoramidis versus 66.7 per cent with placebo-to-acoramidis in the p.Val142Ile subgroup — a variant more prevalent in patients of African ancestry — and 24.3 per cent versus 57.9 per cent across the broader variant population, representing a consistent more than two-fold mortality difference favoring continuous treatment. Acoramidis was well tolerated through Month 54, with no new safety signals identified.

The results have supported BridgeBio's decision to dose the first participant in ASCEND-ATTR, a phase 3b/4 study designed to assess whether acoramidis produces sustained improvement in myocardial structure, function and amyloid burden.

Attruby is approved by the FDA and holds regulatory clearance in the European Union, Japan, Switzerland, the UK and Brazil for the treatment of wild-type or variant ATTR-CM in adults. The most commonly reported adverse reactions versus placebo were diarrhea (11.6 per cent vs 7.6 per cent) and upper abdominal pain (5.5 per cent vs 1.4 per cent), with the majority mild and resolving without drug discontinuation.