BridgeBio Pharma has dosed the first patient in the ASCEND-ATTR Phase 3b/4 study evaluating the long-term impact of acoramidis—commercialized as Attruby—on cardiac structure, function and amyloid burden in adults with transthyretin amyloid cardiomyopathy (ATTR-CM).
The trial plans to enroll approximately 150 participants, who will undergo annual cardiovascular magnetic resonance imaging and echocardiography over a 36-month period. Primary efficacy will be assessed at month 36 based on improvement from baseline in left ventricular systolic function, while secondary endpoints include measures of cardiac function, structure and amyloid load at the same time point. Additional assessments at months 12 and 24 will include echocardiographic measurements, circulating biomarkers and imaging evaluations.
Attruby, a transthyretin stabilizer, is indicated for treating wild-type or variant transthyretin-mediated amyloidosis cardiomyopathy in adults, with the goal of reducing cardiovascular mortality and hospitalizations. Prior data from the ATTRibute-CM CMR substudy and its open-label extension showed changes in cardiac metrics up to month 30, including reductions in Left Ventricular Mass Index and Left Ventricular Systolic Volume Index, alongside improvements in Left Ventricular Ejection Fraction, suggesting amyloid regression in a subgroup of patients.
Findings from the substudy and extension, compared against a natural history cohort, are scheduled for presentation at the 2026 European Society of Cardiology Congress.
In adverse-event data from earlier trials, diarrhea occurred in 11.6% of patients on Attruby versus 7.6% on placebo, while upper abdominal pain was reported in 5.5% versus 1.4%, respectively. Discontinuation rates due to adverse events were 9.3% for Attruby and 8.5% for placebo.
BridgeBio Pharma’s shares closed at $80.40 on Aug. 25, down 0.67 or 0.83%, following a pre-market jump to $84.75 at 02:27 UTC on Aug. 26.
