A Breath of Hope: New PAH Drug Now Publicly Funded Across Canada

KIRKLAND, QC – March 24, 2026 – For Canadians living with the debilitating and life-limiting effects of pulmonary arterial hypertension (PAH), a significant barrier to a new, life-altering treatment has been lifted. Merck Canada announced today that its breakthrough therapy, WINREVAIR® (sotatercept), has been added to public drug formularies in British Columbia, Nova Scotia, Quebec, and for those covered by the Non-Insured Health Benefits (NIHB) program and Veterans Affairs Canada (VAC).

This move marks a critical milestone, making these the first jurisdictions to provide public coverage following a national pricing agreement. The decision brings tangible hope to a patient community grappling with a rare disease that progressively constricts the arteries of the lungs, placing immense strain on the heart.

"Today's announcement represents meaningful progress for Canadians affected by PAH," said Jamie Myrah, Executive Director at the Pulmonary Hypertension Association of Canada. "PAH is a debilitating and progressive disease that places a significant physical, emotional and financial strain not only on patients, but also on the families and caregivers who support them. Increasing access to treatment options is needed to help these patients."

A New Frontier in PAH Treatment

Pulmonary arterial hypertension is a cruel and insidious disease. It causes the small arteries carrying blood from the heart to the lungs to narrow and scar, restricting blood flow and starving the body of oxygen. Patients often experience escalating shortness of breath, fatigue, dizziness, and chest pain, symptoms that can be mistaken for other conditions until the disease is advanced. Without treatment, PAH can lead to heart failure and a drastically reduced life expectancy.

For years, treatments have focused on three main pathways to help relax and open these blood vessels. While beneficial, these therapies often manage symptoms rather than targeting the underlying cellular overgrowth driving the disease. WINREVAIR® represents a paradigm shift. As a first-in-class activin signaling inhibitor, it introduces a fourth, novel treatment pathway. Instead of just dilating blood vessels, it works to rebalance the pro-proliferative and anti-proliferative signals that cause the arteries to narrow in the first place.

The clinical data supporting the drug is formidable. The Phase 3 STELLAR trial showed that when added to existing PAH therapies, WINREVAIR® reduced the risk of death or a clinical worsening event by an astounding 84% compared to placebo. Patients in the trial also saw a significant improvement in their exercise capacity, walking an average of 41 meters further in a six-minute walk test—a key indicator of functional improvement and quality of life.

Navigating Canada's Complex Drug Access Maze

The journey from a successful clinical trial to a patient's prescription is a long and complex one in Canada, particularly for high-cost drugs for rare diseases. The recent listings for WINREVAIR® are the culmination of successful negotiations between Merck and the pan-Canadian Pharmaceutical Alliance (pCPA), an body that leverages the collective buying power of provincial, territorial, and federal drug plans to negotiate prices for new medicines.

Negotiations for WINREVAIR® began in April 2025 and concluded with an agreement in November 2025, paving the way for individual jurisdictions to add the drug to their formularies. However, the path was not without its hurdles. The high price tag of the therapy—with an estimated acquisition cost of nearly $200,000 per patient in the first year—drew scrutiny from Canada's Drug Agency (CDA).

In its review, the CDA acknowledged the drug's significant clinical benefits but flagged its cost-effectiveness. The agency's report noted that a price reduction of approximately 95% would be required for the drug to be considered cost-effective under the standard threshold. While the final negotiated price remains confidential, the CDA recommended reimbursement with conditions: WINREVAIR® should be used as an add-on to optimal background therapy for patients with confirmed WHO Group 1 PAH who are not considered low risk. This ensures the therapy is targeted to patients who stand to benefit most, while attempting to manage the significant budget impact.

The Road Ahead for National Coverage

While the announcements from B.C., Quebec, Nova Scotia, NIHB, and VAC are a major victory, they also highlight the patchwork nature of drug access in Canada. Patients in other provinces, including Ontario, Alberta, and Manitoba, are still waiting for their governments to finalize and implement public coverage. The timeline for these decisions remains uncertain, creating a potential disparity in care across the country.

Historically, access to drugs for rare diseases has been slower and less consistent in Canada compared to other developed nations, with wait times from regulatory approval to public reimbursement often stretching for years. This reality leaves patients and their families in a state of anxious limbo.

"This is an important step toward expanding access to therapies for people living with PAH, and we remain committed to working collaboratively with remaining jurisdictions to ensure timely access for all eligible Canadian patients," stated David Jones, Managing Director of Merck Canada, acknowledging the work that still lies ahead.

The Business of Hope

The arrival of WINREVAIR® also highlights the booming and often controversial market for expensive drugs for rare diseases (EDRDs). This segment of the pharmaceutical industry has seen explosive growth in Canada, with sales growing at a compound annual rate of over 30% in the last two decades, far outpacing the rest of the branded drug market. This growth presents both a lifeline for patients with few options and a profound challenge for publicly funded healthcare systems.

For Merck, WINREVAIR® is a strategic cornerstone and a major financial success. The drug generated $1.4 billion in global sales in 2025, demonstrating its blockbuster potential. Securing public reimbursement in Canada is a crucial step for the company to solidify its market position and ensure a return on its significant research and development investment. The high per-patient cost means that even with a relatively small patient population, the drug represents a substantial revenue stream, underscoring the high stakes for both the company and the public payers footing the bill.