Why Is Heart Disease-Focused Milestone Pharmaceuticals Stock Plummeting Today?

Milestone Pharmaceuticals Inc MIST announced Tuesday that the Company received a Refusal to File (RTF) letter from the FDA for the New Drug Application seeking approval for self-administered etripamil nasal spray for paroxysmal supraventricular tachycardia (PSVT).

Upon preliminary review, the FDA determined that the NDA, submitted in October 2023, was not sufficiently complete to permit substantive review. 

The FDA requested clarification about the time of data recorded for adverse events in Phase 3 clinical trials.

The FDA did not express concerns about the nature or severity of adverse events. Milestone will seek clarification and is in the process of planning a meeting with the FDA.

An estimated two million people in the U.S. are currently diagnosed with PSVT, which is a type of arrhythmia or abnormal heart rhythm. 

PSVT is characterized by episodes of rapid heartbeats, often exceeding 150 to 200 beats per minute. Key features of PSVT include the sudden occurrence of episodes and very rapid heart rate. 

Price Action: MIST shares are down 32.30% at $1.95 on the last check Tuesday.