- An experimental drug for pulmonary arterial hypertension helped improve patients’ fitness when added to other drugs in a clinical trial, as well as delaying death or worsening of the disease, Merck & Co. said Monday. The company acquired the drug, called sotatercept, with its $11.5 billion acquisition of Acceleron one year ago.
- Patients who received sotatercept plus background therapy were able to walk significantly further than patients given only standard therapy in a six-minute test after 24 weeks of treatment, meeting the trial’s main goal. The test is a common measure used in trials of cardiovascular disease drugs.
- Success with sotatercept is important for Merck as the patents for its biggest moneymaker, the cancer drug Keytruda, near expiration in 2028. If successful, sotatercept would join the heart failure drug Verquvo in Merck’s cardiovascular business. The company also has high hopes for a high cholesterol drug candidate as well as a second pulmonary arterial hypertension treatment.
Pulmonary arterial hypertension is primarily treated with drugs that dilate the blood vessels in the lungs. Constriction of those blood vessels impairs physical activity and can lead to heart failure and early death.
Sotatercept is an injected drug that alters biological pathways that lead to thickened blood vessel walls and in turn hypertension, and therefore could be used as part of a combination therapy.
This is what Acceleron wanted to prove when it began the Phase 3 STELLAR trial in 2020, before Merck acquired the company. STELLAR enrolled 324 patients who were stable on background therapy and randomized half to receive on top of that treatment either sotatercept or a placebo.
On the six-minute walk test, Merck said patients receiving sotatercept showed a “statistically significant and clinically meaningful improvement” when compared to those given a placebo. Sotatercept met eight of nine secondary measures, including a multi-component assessment based on the walk test, biological signs and clinical classification. Sotatercept also outperformed placebo on a measure of time to death or clinical worsening.
The one missed endpoint measured cognitive and emotional impacts, Merck said. The company said side effects to sotatercept were “in general consistent” with what was reported in Phase 2 trials, which included suppressed blood platelet levels.
Merck didn’t disclose detailed data, which will be fully outlined at an upcoming medical meeting.
“We believe that in totality, the results observed in the STELLAR study suggest that sotatercept has the potential to transform the treatment of patients with PAH,” Dean Li, president of Merck Research Laboratories, said in a statement. “We are moving with urgency on our regulatory applications to bring this investigational therapy to these patients.”
The Food and Drug Administration has granted sotatercept Breakthrough Therapy designation, which could enable a speedy regulatory submission and review if regulators agree with Merck’s views of the STELLAR data.
STELLAR tested patients whose disease has progressed to the point where regular activities may cause them to be short of breath. Two other trials are underway, one in newly diagnosed patients and one that includes patients who have symptoms even when at rest.
Acquiring Acceleron was Merck’s biggest deal since a $41 billion merger with Schering Plough in 2009. It also was the first major biotech buyout brokered by CEO Robert Davis and research head Dean Li, who took over last year from longtime executives Ken Frazier and Roger Perlmutter, respectively.