Alnylam's Closely Watched Phase 3 Heart Disease Trial Of Vutrisiran Hits Primary Endpoint, Shares Surge

Monday, Alnylam Pharmaceuticals Inc ALNY revealed topline results from its HELIOS-B Phase 3 study of vutrisiran, an investigational RNAi therapeutic in development for ATTR amyloidosis with cardiomyopathy (ATTR-CM).

ATTR-CM is a type of heart muscle disease that occurs when amyloid fibrils – clumps of misfolded proteins – are deposited into heart tissue and cause it to stiffen.

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The study met the primary endpoint, demonstrating a statistically significant reduction in the composite of all-cause mortality and recurrent cardiovascular (CV) events during the double-blind period in both the overall population (HR 0.718, p-value 0.0118; n=654) and in the monotherapy population (patients not receiving tafamidis at baseline; HR 0.672, p-value 0.0162; n=395).

The study also demonstrated statistically significant improvements across all secondary endpoints in both the overall and monotherapy populations.

This includes key measures of disease progression: 6-minute walk test (6-MWT), Kansas City Cardiomyopathy Questionnaire (KCCQ), and New York Heart Association (NYHA) Class at Month 30 (p<0.025 for all).

Vutrisiran treatment also reduced all-cause mortality in the overall population (HR 0.645, p<0.025) and the monotherapy population (HR 0.655, p<0.05) up to Month 42.

In addition, vutrisiran demonstrated consistent effects on the primary composite endpoint and all secondary endpoints across all key subgroups, including baseline tafamidis use, ATTR disease type, and measures of disease severity.

In the HELIOS-B study, vutrisiran demonstrated encouraging safety and tolerability, consistent with its established profile. Rates of adverse events (AEs), serious AEs, and AEs leading to study drug discontinuation were similar between the vutrisiran and placebo arms.

The company plans to proceed with global regulatory submissions starting later this year, including filing a supplemental New Drug Application with the FDA using a Priority Review Voucher.

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Price Action: ALNY shares are up 29.2% at $214.15 at last check Monday.

Illustration of Phrama lab worker created with MidJourney.