Merck’s Winrevair approved in Canada for treating adults with PAH
OK covers drug with standard therapies for WHO functional class 2, 3
Health Canada has approved Merck’s Winrevair (sotatercept-csrk) for adults with pulmonary arterial hypertension (PAH).
The approval specifically covers the use of Winrevair in combination with standard therapies to treat patients with World Health Organization (WHO) functional classification 2 or 3. The decision follows approvals in the U.S., as well as the European Union, Iceland, Liechtenstein, and Norway.
“We understand the burden that PAH places on patients and caregivers. The approval of Winrevair represents a step forward for those grappling with this disease,” David D. Jones, managing director of Merck Canada, said in a company press release. “Our commitment to advancing scientific research and developing solutions stands firm to address the unmet needs of Canadians.” Merck is known as MSD outside the U.S. and Canada.
PAH’s hallmark symptom is the narrowing of the pulmonary arteries that transport blood from the heart to the lungs due to the abnormal growth of endothelial cells, which line blood vessels. Signaling molecules called growth factors drive this process.
Results of clinical testing of Winrevair
The active ingredient in Winrevair is a fragment of a growth factor receptor that traps growth factors in excess, the aim being to ultimately inhibit cell growth. Winrevair is administered once every three weeks via injections under the skin, or subcutaneously.
Data from the Phase 3 STELLAR trial (NCT04576988) supported the therapy’s approvals. A total of 323 participants with PAH were randomly assigned to a placebo or to Winrevair in addition to standard treatments for nearly six months. Patients received doses starting at 0.3 mg/kg up to 0.7 mg/kg.
Most participants had idiopathic, or unknown cause, PAH (59%), followed by heritable PAH (18%), and PAH associated with connective tissue diseases (15%). Most (61%) were receiving three background treatments for PAH, whereas 35% received two. About 40% were treated with prostacyclin medications, which work to widen blood vessels.
Data at the end of the study showed Winrevair led to a significant increase in the distance walked in six minutes, a standard test of exercise endurance, over the start of the study for a mean difference of 40.8 meters, or about 134 feet.
Also, more patients in the Winrevair group saw an improvement in WHO functional class than those on the placebo (29% vs. 14%). Further benefits included a more than 80% lower risk of clinical worsening or death relative to a placebo, and improved heart health and blood flow. The therapy also was predicted to extend patient survival by more than 11 years.
Headache and nose bleeds were among the most frequent side effects. Others were skin redness and rash, dilated veins under the skin, diarrhea, and dizziness.
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