BridgeBio Pharma's Attruby (acoramidis) has received FDA approval for the treatment of adults with cardiomyopathy caused by transthyretin-mediated amyloidosis (ATTR-CM), marking a significant development in the treatment landscape for this increasingly prevalent cardiovascular condition. The approval sets the stage for competition with Pfizer's established drug, tafamidis, while also facing potential future competition from Alnylam Pharmaceuticals and others.
Clinical Trial Data and Efficacy
The FDA's decision was based on data from a Phase 3 clinical trial involving 632 patients with ATTR cardiomyopathy. The study demonstrated that Attruby led to a statistically significant improvement in a composite endpoint comprising four measures of the disease, including cardiovascular death and cardiovascular-related hospitalization. These results were published in the New England Journal of Medicine. BridgeBio CEO Neil Kumar emphasized that Attruby is the "only oral stabilizer with the verbiage 'near-complete stabilization' in the label," suggesting a potentially more effective mechanism of action compared to existing treatments.
Mechanism of Action and Disease Context
ATTR cardiomyopathy is characterized by the buildup of misfolded transthyretin (TTR) protein in the heart, leading to impaired cardiac function. Attruby is a small molecule designed to bind to and stabilize the abnormal TTR protein, preventing the formation of amyloid deposits. Pfizer's tafamidis, also a TTR stabilizer, has been the standard of care since its approval in 2019. However, BridgeBio aims to demonstrate that Attruby offers superior stabilization and clinical benefits.
Market Dynamics and Competition
BridgeBio estimates that 500,000 patients in the U.S. and European Union have ATTR cardiomyopathy, representing a substantial market opportunity. Pfizer's tafamidis generated $3.9 billion in sales in the first nine months of 2024, highlighting its dominance in the current market. Alnylam Pharmaceuticals is also developing vutrisiran, a gene-silencing therapy administered via subcutaneous injection, for ATTR cardiomyopathy, with a potential FDA decision expected in March 2025. The increasing number of treatment options is expected to intensify competition and provide physicians with more choices for managing this complex disease.
Pricing and Cost-Effectiveness
BridgeBio has priced Attruby at $18,759.12 for a 28-day supply, which translates to approximately $244,500 annually. This is a slight discount compared to Pfizer's tafamidis, which is priced at $267,987 annually. However, both drugs are significantly above the cost-effectiveness price range of $13,600 to $39,000 calculated by the Institute for Clinical and Economic Review (ICER).
Future Outlook
Attruby is currently under review in Europe, with a regulatory decision anticipated in 2025. Bayer holds exclusive rights to market the drug in Europe for ATTR cardiomyopathy under a licensing agreement with BridgeBio. While challenges remain in competing with Pfizer's established market presence, BridgeBio aims to capture a significant share of the ATTR-CM market by highlighting Attruby's potential for near-complete TTR stabilization and early onset of clinical benefits.
