Alnylam therapy for form of heart disease succeeds in closely watched trial

Alnylam Pharmaceuticals’ treatment for an increasingly common heart disease succeeded in a closely watched clinical trial, the company said Wednesday, clearing the path to approval and affirming the promise of a drug analysts expect to reap blockbuster sales.

Patients treated with the intravenous drug, called patisiran, did significantly better than those taking a placebo on a test of how far they could walk over the course of six minutes, meeting the study’s primary goal. The 12-month trial enrolled 360 patients with ATTR-CM, a progressive heart disease. The so-called six-minute walk test is a widely accepted metric in cardiovascular medicine, one that correlates with whether a given treatment can prevent hospitalization and death in the long term.