FDA Approval Marks New Treatment Option for ATTR-CM

On March 21, 2025, the FDA approved Alnylam’s vutrisiran (Amvuttra®) for the treatment of transthyretin-mediated amyloidosis with cardiomyopathy (ATTR-CM), a progressive and fatal condition characterized by misfolded protein deposits in the heart. Vutrisiran is an RNA interference (RNAi) therapeutic designed to reduce production of disease-causing transthyretin protein, thereby slowing disease progression.

This marks the second indication for vutrisiran, which is already approved for polyneuropathy caused by hereditary transthyretin-mediated amyloidosis (hATTR-PN). The new approval establishes Amvuttra as a differentiated, once-quarterly subcutaneous treatment option for patients with cardiac involvement.

Clinical Trial Evidence Supports Efficacy and Safety

The phase 3 HELIOS-B trial demonstrated that vutrisiran significantly improved cardiac function, quality of life, and survival compared to placebo, with a safety profile consistent with the RNAi class. These benefits were observed across diverse patient populations, including those with both wild-type and hereditary forms of ATTR-CM.

Alnylam CEO Yvonne Greenstreet highlighted the approval as “a new and clinically differentiated treatment option that has the potential to improve outcomes and quality of life for patients living with ATTR-CM.”

Market Impact and Competitive Landscape

Amvuttra will compete with tafamidis (Vyndaqel) and other emerging therapies targeting transthyretin amyloidosis but offers advantages of less frequent dosing and a distinct mechanism that “silences” transthyretin production. Analysts forecast that the ATTR-CM market could reach billions annually as diagnosis rates improve and treatment options expand.

Outlook: RNAi Therapeutics Strengthen Rare Disease Portfolio

The FDA’s clearance of vutrisiran in ATTR-CM underscores the growing impact of RNAi technology in treating complex diseases. Alnylam continues to advance its RNAi pipeline addressing rare and common conditions, building on its pioneering leadership in gene-silencing therapies.