Rare Daily Staff

Acceleron Pharma reported that the PULSAR phase 2 trial of sotatercept met its primary and key secondary endpoints in patients with pulmonary arterial hypertension. Shares of the biotech soared 67 percent on the news.

Pulmonary arterial hypertension (PAH) is a rare and chronic, rapidly progressing disorder characterized by the constriction of small pulmonary arteries and elevated blood pressure in the pulmonary circulation. PAH results in significant strain on the heart, often leading to limited physical activity, heart failure, and reduced life expectancy. The 5-year survival rate for patients with PAH is approximately 57 percent. Available therapies generally act by promoting the dilation of pulmonary vessels without addressing the underlying cause of the disease. PAH often progresses rapidly for many patients despite standard of care treatment.

Sotatercept is an experimental therapy that targets the primary drivers of PAH in familial, idiopathic, and acquired forms of the disease. In preclinical studies of PAH, sotatercept reversed pulmonary vessel muscularization and improved indicators of right heart failure.

In patients on stable background PAH-specific therapies, sotatercept demonstrated a statistically significant reduction in pulmonary vascular resistance (PVR), the trial’s primary endpoint, at week 24 versus placebo. The trial also achieved a statistically significant improvement in the key secondary endpoint of 6-minute walk distance (6MWD), a measure of functional capacity/endurance, as well as other secondary endpoints.

Sotatercept was generally well tolerated in the trial. Adverse events observed in the study were generally consistent with previously published data on sotatercept in other diseases.

“The PULSAR data demonstrate that this novel approach has the potential to provide significant benefit on top of currently available therapies,” said Marc Humbert, professor of medicine and director of the French Pulmonary Hypertension Reference Center at the Université Paris-Saclay, and an investigator in the trial.

Acceleron plans to present a detailed review of the topline results from the PULSAR phase 2 trial of sotatercept at a medical conference later this year. Plans to discuss a phase 3 study with regulators are also in the works. Sotatercept is also being evaluated in the SPECTRA phase 2 trial in patients with PAH.

Photo: Marc Humbert, professor of medicine and director of the French Pulmonary Hypertension Reference Center at the Université Paris-Saclay, and an investigator in the trial.

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