Milestone Pharmaceuticals Stock Plunges 60% After FDA Declines To Approve Its Cardamyst Nasal Spray – But Retail’s Positive

The FDA said an inspection is required at a facility where the company performed release testing for the product to ensure it complies with Current Good Manufacturing Practices.

Shares of Milestone Pharmaceuticals Inc. (MIST) traded 60% lower on Friday after the Food and Drug Administration (FDA) did not approve its lead investigational product, Cardamyst.

The nasal spray is under development to treat episodes of abnormal heart rhythm associated with Paroxysmal supraventricular tachycardia (PSVT).

The FDA highlighted two key Chemistry, Manufacturing and Controls (CMC) issues.

The regulator asked the company to submit additional information on nitrosamine impurities based on the new draft guidance issued after the New Drug Application (NDA) submission.  

The agency also said an inspection is required at a facility where the company performed release testing for the product to ensure it complies with Current Good Manufacturing Practices.

Milestone Pharmaceuticals CEO Joe Oliveto said that the company is “deeply disappointed” by the letter but remains committed to the potential of the drug in treating patients with PSVT.

“Our team is evaluating the feedback provided and intends to request a Type A meeting to discuss the issues raised in the CRL,” Oliveto said. “We are appreciative of the FDA’s efforts and are confident we can collaborate with the agency with the goal of addressing these issues in a resubmission.”

The FDA did not raise any concerns regarding the drug’s clinical safety or efficacy, the company said.

The nasal spray has been designed as a self-administered rapid response therapy, thereby bypassing the need for immediate medical oversight, it explained.

On Stocktwits, retail investor sentiment about Milestone Pharmaceuticals dropped slightly within the ‘extremely bullish’ territory (89/100), while message volume remained at ‘extremely high’ levels over the past 24 hours.

Following the company’s announcement, HC Wainwright kept a ‘Buy’ rating on Milestone pharmaceuticals and noted that the FDA flagged no concerns around the efficacy of the product, thereby reaffirming the integrity of the clinical data.

However, the firm expects the product's launch to be delayed until the first half of 2026.

Shares of Milestone Pharmaceuticals fell over 55% this year and by over 45% over the past 12 months.

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