Alnylam Pharmaceuticals (NASDAQ:ALNY) fell ~14% in the premarket on Friday after releasing complete results from a late-stage trial for its heart disease drug vutrisiran that can potentially rival Pfizer’s (NYSE:PFE) blockbuster therapy tafamidis.

The treatment identified as RNA interference therapy is targeted at cardiomyopathy of transthyretin amyloidosis, which is caused by the abnormal accumulation of a certain misfolded protein, known as transthyretin, in various parts of the body.

Alnylam (ALNY) already sells vutrisiran as Amvuttra for adults with polyneuropathy of the disease, and its Phase 3 trial, known as HELIOS-B, was aimed at expanding it for ATTR amyloidosis with cardiomyopathy (ATTR-CM).

BridgeBio (BBIO), whose ATTR-CM therapy acoramidis is currently under FDA priority review, climbed ~16% in reaction, while Pfizer (PFE) was marginally up.

In June, Alnylam (ALNY) posted HELIOS-B’s initial data, noting that the multicenter, global study met primary and secondary endpoints, leading to a 28% and 33% reduction in the composite measure of all-cause mortality and recurrent cardiovascular events.

Its detailed data disclosed at a European medical event on Friday indicated that vutrisiran led to a 28% reduction in the primary composite of all-cause mortality and recurrent cardiovascular events.

As for all-cause mortality, vutrisiran cut the incidence by 31% and 36% during the 33-36-month double-blind period and up to month 42, respectively.

Alnylam (ALNY) said the drug’s safety and tolerability profiles were in line with previously established trial data and results from the currently approved patient population.

The results from HELIOS-B were simultaneously published in The New England Journal of Medicine. The company remains on track to start global regulatory submissions for vutrisiran later this year.