BridgeBio Pharma Presents Cardiac Magnetic Resonance (CMR) Imaging Evidence Consistent with Clinical Improvement Observed in the ATTRibute-CM Phase 3 Study in Patients with Transthyretin Amyloid Cardiomyopathy (ATTR-CM) - Seite 2

“CMR is the reference non-invasive imaging method to evaluate cardiac structure, function, and amyloid burden in patients with ATTR-CM. The results shown in the imaging substudy are indicative of potential improvement of cardiac structure and function in patients with ATTR-CM, consistent with the clinical outcomes with acoramidis treatment observed in the ATTRibute-CM Phase 3 clinical trial. The impact on cardiac amyloid load highlights the potential that acoramidis could lead to cardiac amyloid regression in a proportion of patients with ATTR-CM, which we have not observed in such a controlled clinical trial to date,” said Marianna Fontana, M.D., Ph.D., Professor of Cardiology and Honorary Consultant Cardiologist at the National Amyloidosis Centre, Division of Medicine, University College London, and Principal Investigator of the Substudy.

CMR imaging was performed at baseline before the first dose in 35 participants or within three months after the first dose in 17 participants (range, 14-105 days); subsequent CMR imaging was performed at months 12, 24, and 30 in those individuals who were available to undergo imaging, which was influenced by survival. Images were read centrally at the National Amyloidosis Centre in a fashion blinded to other clinical data. Findings included:

• Key CMR imaging parameters measuring cardiac structure, including mean indexed left ventricular mass, were found to be stable or have a trend towards improvement on acoramidis vs. deteriorated on placebo over 30 months
• Treatment with acoramidis preserved or was associated with a trend towards improvement in measures of cardiac function including left ventricular ejection fraction and stroke volume compared to initial measures, and relative to placebo

In July 2023, BridgeBio announced positive results from ATTRibute-CM, reporting a highly statistically significant result, demonstrated by a Win Ratio of 1.8 (p<0.0001) on the primary endpoint (a hierarchical analysis prioritizing in order: all-cause mortality, then frequency of cardiovascular hospitalization, then change from baseline in N-terminal prohormone of brain natriuretic peptide, then change from baseline in 6-minute walk distance). Acoramidis was well-tolerated, with no safety signals of potential clinical concern identified. BridgeBio has also presented analyses from ATTRibute-CM at the European Society of Cardiology Congress 2023 and at the American Heart Association Scientific Sessions 2023. In February 2024, BridgeBio shared positive results of a single-arm Phase 3 study of acoramidis in Japanese patients with ATTR-CM, including no mortality observed in the trial at 30 months.