Charlotte’s Milestone Pharmaceuticals gains FDA approval for heart drug

Milestone Pharmaceuticals, a Canadian company with a U.S. subsidiary in Charlotte, is starting the new year with its first approved drug.

The company received notice from the U.S. Food and Drug Administration on Dec. 12 that its first commercial product, a treatment for a heart rhythm disorder, had been approved for sale.

The approval is for Cardamyst (etripamil) nasal spray, a prescription medication for treating paroxysmal supraventricular tachycardia (PSVT), a type of abnormal, rapid heart rhythm that mostly affects women.

“The FDA approval of Cardamyst is a watershed moment for Milestone and a gratifying event for our team members, patients, clinical investigators and health care providers who participated in the development program, all of whom I sincerely thank for their dedication, counsel and collaboration toward this important achievement,” said Joseph Oliveto, president and chief executive officer of Milestone.

Fast relief for racing hearts

The approval marks the first time that more than 2 million Americans with PSVT will have a rapid-acting treatment option they can self-administer outside the emergency department or other healthcare setting, the company said in a news release.

“Cardamyst is a novel at-the-ready treatment option that addresses the unpredictable impact of PSVT by offering patients the freedom to manage episodes anytime and anywhere,” Oliveto said.

PSVT, also called SVT, is characterized by rapid-onset episodes of abnormally fast heart rates – commonly 150 to 250 beats per minute – along with sweating, anxiety, dizziness, fainting, fatigue and chest pain. People with PSVT typically have multiple episodes that require treatment every year.

Until now, successful treatment options often required a trip to the hospital, either for IV drug administration or catheter ablation – an invasive procedure to block electrical signals to the heart. Both options create stress and costs for patients and their insurers.

Cardamyst offers a new treatment approach, enabling adults to self-administer the medication quickly and easily at the onset of symptoms.  

“Our goal is that Cardamyst will become a trusted and essential solution for healthcare providers and their patients,” said Lorenz Muller, chief commercial officer of Milestone. “Our team is focused on making Cardamyst available to adults with PSVT as quickly as possible, including actively working to secure insurance coverage and begin the distribution of the product through retail pharmacies.”

Cardamyst is expected to be available in pharmacies in the first quarter of 2026.

The list price of Cardamyst for wholesalers will be $1,649 per prescription – much cheaper than treatments requiring emergency room or hospital visits, which can run into tens of thousands of dollars, according to a company presentation to investors. PSVT costs about $5 billion in healthcare expenditures annually.

Made in North Carolina

Milestone will rely on a global supply chain and contract manufacturers to produce Cardamyst. A North Carolina company is one of two contractors that will provide final fill, finish and packaging services for the combination drug-device product, Oliveto said. Non-disclosure agreements prevent Milestone from naming those companies, he said.

Milestone has begun hiring a 60-person national sales staff for the commercial launch. Those representatives will be tasked with reaching about half of the 1 million PSVT patients treated annually by calling on about 10,000 prescribers, mostly cardiologists, Oliveto said.

Cardamyst is administered intranasally with a small pre-filled device. A spray in each nostril – equaling one dose – should slow the rapid heart rates in PSVT within 10 minutes. If not, another dose in a second device should bring relief.

The active ingredient in Cardamyst, etripamil, is a calcium channel blocker, a class of drugs used to reduce the amount of calcium entering the cells of heart muscle and blood vessels. Restricting calcium, an electrolyte involved in sending electrical signals to the heart, is a proven way of treating various arrhythmias.

“Adults with SVT have been waiting a long time for the day when they can confidently self-administer Cardamyst to treat their SVT episodes,” said Annette Greene, a Cardamyst clinical trial participant and administrator of the 30,000-member Supraventricular Tachycardia Group on Facebook. “It is very exciting that the day has become a reality.”

Milestone sponsors a support website for PVST patients at www.SVTHearttoHeart.com.

Drug also proposed for Europe

On the heels of Cardamyst’s approval in the U.S., Milestone announced in January that etripamil nasal spray was also working its way through the European regulatory process.

The European Medicines Agency (EMA) accepted a Marketing Authorization Application from Milestone seeking the approval of etripamil nasal spray for PSVT. A decision is expected by the first quarter of 2027.

Etripamil has the conditionally approved brand name Tachymist in Europe, where about 2 million people suffer from PSVT.

The regulatory application incorporates the global clinical data package that supported the U.S. FDA’s approval of etripamil. That data included efficacy, safety and tolerability results of a clinical trial program involving 1,800 participants and more than 2,000 episodes of PSVT.

Results of a global Phase 3 trial were published in The Lancet in 2023. Participants using etripamil were two times more likely to convert symptomatic PSVT to sinus rhythm – a normal heartbeat – and did so more than three times faster compared with placebo.

Another potential indication: AFib-RVR

As Cardamyst comes to market in the U.S., Milestone will work on a second indication for etripamil: the treatment of atrial fibrillation with rapid ventricular rate, or AFib-RVR.

The market for AFib-RVR is much larger than the PSVT market. An estimated 10.5 million Americans suffer from AFib, and that number is expected to grow to about 12 million by 2030. A subset of AFib patients have RVR, an abnormally high heart rate.

Milestone’s initial market research indicates that 30% to 40% of patients with AFib experience one or more symptomatic episodes of RVR per year that require treatment, suggesting a target addressable market of about 3 to 4 million patients in 2030 for etripamil in patients with AFib-RVR.

Milestone is poised to enter a Phase 3 program in AFib-RVR with etripamil following a successful Phase 2 trial.

“We want to keep going,” Oliveto said. “We think this product can help a lot of different patients.”

Charlotte presence grows

Milestone was founded in 2003 in Montreal, and Oliveto established its U.S. subsidiary in Charlotte in 2017. The company became publicly traded in 2019 with an initial public offering of stock that raised $95 million. Milestone is listed on the Nasdaq stock exchange under the symbol MIST.

The company’s workforce has grown from about 30 last year to about 80 employees and dedicated contractors today. About 20 people work from Milestone’s Charlotte office, another 10 work in Montreal, and about 50 others are scattered throughout the United States, Oliveto said.

The hiring of a national sales force for Cardamyst will push total employment to about 140 people.

The company raised net proceeds of $48.7 million in July 2025 through a public stock offering. Milestone also expects to receive $75 million from a royalty purchase agreement with RTW Investments in exchange for tiered royalty payments on the annual net product sales of etripamil in the United States.

The combined funding makes the company “well-capitalized” for the Cardamyst launch, Milestone said. As of September 30, 2025, the company had $82.6 million in cash.