Pfizer's competitor vutrisiran from Alnylam Pharmaceuticals (ALNY.US) failed to meet statistical significance in a trial

Alnylam Pharmaceuticals (ALNY.US) shares fell more than 8% in pre-market trading on Friday after the company released the full results of its late-stage trial of its heart disease drug vutrisiran. The results showed a 30% relative reduction in the risk of death in the monotherapy group, but this reduction did not reach statistical significance. The drug is also believed to be a potential competitor to Pfizer's (PFE.US) blockbuster therapy tafamidis.

Vutrisiran uses RNA interference therapy to target transthyretin amyloid cardiomyopathy (ATTR-CM), a disease caused by the abnormal accumulation of misfolded transthyretin in the body.

In addition to the monotherapy group, the study included patients receiving standard therapy (such as tafamidis and SGLT2 inhibitors). Detailed data released during a European medical event on Friday showed that vutrisiran reduced the primary composite endpoint of all-cause mortality and recurrent cardiovascular events by 28%. The drug reduced the incidence by 31% and 36% at 33-36 months and up to 42 months, respectively, in the double-blind period.

Alnylam Pharmaceuticals emphasized that the safety and tolerability of vutrisiran were consistent with previous trial data and results in the currently approved patient population. The HELIOS-B study results were published in the New England Journal of Medicine. The company plans to submit a marketing application for vutrisiran to global regulatory agencies later this year.

Alnylam Pharmaceuticals has already launched vutrisiran under the brand name Amvuttra for the treatment of adult polyneuropathy and is conducting a Phase 3 trial, HELIOS-B, to expand its indication to ATTR amyloidosis with cardiomyopathy. Meanwhile, BridgeBio's (BBIO.US) ATTR-CM therapy acoramidis is currently under priority review by the U.S. Food and Drug Administration (FDA), and the news caused BridgeBio's shares to rise about 16% and Pfizer's shares to rise slightly.

It is worth noting that Alnylam Pharmaceuticals released preliminary data from the HELIOS-B trial in June, showing that the global, multicenter study met its primary and secondary endpoints, reducing the composite endpoint of all-cause mortality and recurrent cardiovascular events by 28% and 33%, respectively.