A Formidable First: Winrevair

Merck & Co. has put the syringe in the patient’s hand with sotatercept, marketed as Winrevair, a prescription medicine used to treat adults with pulmonary arterial hypertension (PAH). The rare and life-threatening condition affects about 500 to 1,000 Americans each year, often women between the ages of 30 and 60, according to the American Lung Association.¹

After being granted priority review in September 2023,² Winrevair, a first-in-class therapeutic fusion protein, was approved by FDA in March 2024.³ The therapy is available in one and two vial subcutaneous injection kits to be administered once every three weeks. Patients don’t necessarily need to see a doctor or healthcare provider (HCP) to be able to take Winrevair. HCP guidance, training, and follow-up allow the drug to be prepped, mixed, and administered by appropriate patients or caregivers with guidance.

FDA’s approval was based on the Phase III STELLAR trial that compared Winrevair to a placebo, both in combination with background standard-of-care therapies in adult patients with PAH. Study results showed adding Winrevair increased six-minute walk distance from baseline by 41 meters at week 24 and significantly improved multiple important secondary outcome measures, including reducing the risk of death from any cause or PAH clinical worsening events by 84% versus background therapy alone.

“PAH patients currently have a poor prognosis, with an estimated five-year mortality rate of 43%,” a company spokesperson told Pharmaceutical Executive. “Winrevair is offering PAH patients a treatment option in a new treatment pathway. In PAH, the excessive cell proliferation in the lung artery walls leads to thickening and narrowing, leading to excessive strain on the heart. By improving the balance between pro- and anti-proliferative signaling, Winrevair regulates vascular cell proliferation underlying PAH.”

The disorder can result in heart failure, reduced physical activity, and reduced life expectancy among other adverse effects. Mere weeks after Winrevair’s US approval, Merck launched an educational campaign around the rare disease.

“Outnumber PAH,” launched in partnership with three nonprofit organizations (the Pulmonary Hypertension Association, the National Scleroderma Foundation, and the Phaware Global Association), is aimed predominantly at people diagnosed with PAH. The website offers support for both newly diagnosed patients and those further along in their journey. It also provides direction for caregivers, family, and friends. Other resources include a conversation guide, patient stories, and a downloadable contact sheet for a personalized “PAH support team.”

Ensuring patient access to Winrevair, especially considering its potential high cost, will be crucial for the drug’s success. The cost for a supply of one kit of a Winrevair csrk 45 mg subcutaneous kit is reportedly around $14,750.⁴ To estimate affordability, Merck established the Merck Access Program (MAP). “Merck offers support to patients who are prescribed Winrevair, including information about insurance coverage and help for eligible patients with out-of-pocket costs and copay assistance options through the Merck Access Program,” said a company spokesperson.

Once enrolled, patients are connected with the MAP patient navigator that helps them understand their insurance coverage. Caregiver support and resources can also be found.

The PAH space is already competitive with several other treatment options available. The market size, according to DataHorizzon Research, was valued at $7.5 billion in 2023 and is expected to reach a market size of $12.2 billion by 2032 at a compound annual growth rate of 5.5%.⁵ Johnson & Johnson is currently the dominant player in the space, accounting for about half the market with a portfolio that includes drugs such as Uptravi, Ventavis, and Opsumit. Other notable players in this area include Bayer, United Therapeutics, and Pfizer.

For Winrevair, a key to future fortunes will hinge on the treatment’s long-term data. Merck intends to build on the results of the STELLAR study that supported approval and expand the understanding of Winrevair to a broader range of patients with PAH.

“Ongoing Phase III trials, ZENITH and HYPERION, are evaluating Winrevair in patients with more advanced disease and those earlier in their disease journey to potentially expand access beyond the patient population evaluated in STELLAR,” the company said. Merck added that it’s currently evaluating an auto-injector option in its pipeline to increase convenience for patients.

Sotatercept was the centerpiece asset in Merck’s 2021 acquisition of Acceleron Pharma.⁶

References

1. Learn About Pulmonary Arterial Hypertension. American Lung Association. https://www.lung.org/lung-health-diseases/lung-disease-lookup/pulmonary-arterial-hypertension/learn-about-pulmonary-arterial-hypertension

2. Merck Receives Priority Review from FDA for New Biologics License Application for Sotatercept, an Activin Signaling Inhibitor to Treat Adults with Pulmonary Arterial Hypertension (PAH). Merck press release. September 28, 2023. https://www.merck.com/news/merck-receives-priority-review-from-fda-for-new-biologics-license-application-for-sotatercept-an-activin-signaling-inhibitor-to-treat-adults-with-pulmonary-arterial-hypertension-pah/

3. FDA Approves Merck’s WINREVAIR™ (sotatercept-csrk), a First-in-Class Treatment for Adults with Pulmonary Arterial Hypertension. Merck press release. March 26, 2024. https://www.merck.com/news/fda-approves-mercks-winrevair-sotatercept-csrk-a-first-in-class-treatment-for-adults-with-pulmonary-arterial-hypertension-pah-who-group-1/

4. Winrevair Prices, Coupons, Copay Cards & Patient Assistance. Drugs.com. https://www.drugs.com/price-guide/winrevair#:~:text=Winrevair%20(sotatercept)%20is%20a%20member,on%20the%20pharmacy%20you%20visit

5. Pulmonary Arterial Hypertension Market To Reach USD 12.2 Billion By 2032 | DataHorizzon Research. Yahoo! May 10, 2024. https://finance.yahoo.com/news/pulmonary-arterial-hypertension-market-reach-090000548.html

6. Merck Agrees to Acquire Acceleron Pharma for $11.5bn. Pharmaceutical Technology. October 1, 2021. https://www.pharmaceutical-technology.com/news/merck-acceleron-pharma/