Alnylam market cap gains billions on results of heart drug trial

Alnylam Pharmaceuticals Inc. said Wednesday morning that a 12-month trial of one of its RNA-blocking drugs met its primary goal, propelling its stock up more than 50% as of 10 a.m. The Cambridge-based drugmaker said the late-stage study of patisiran showed it did significantly better than a placebo in treating patients with an increasingly common heart condition.