Milestone Pharmaceuticals (MIST) said Friday that the first patient has been enrolled in the phase 3 ReVeRA-301 pivotal trial evaluating etripamil as a treatment for atrial fibrillation with rapid ventricular rate, or AFib-RVR.

The company said the trial's primary endpoint is a reduction in ventricular rate within 30 minutes. The study's key secondary endpoint is symptom improvement via patient-reported outcomes.

Milestone said the trial is an event-driven global Phase 3 study with sites being activated across North America and internationally.

The company said it is seeking FDA approval for a single-study supplemental New Drug Application registration to treat AFib-RVR.

Shares of Milestone Pharmaceuticals were up 4.7% pre-bell.