Acceleron (XLRN) Up On Success Of PAH Drug In Phase II Study

 | Jan 28, 2020 04:22AM ET

Shares of Acceleron Pharma Inc. (NASDAQ:XLRN) soared more than 66% in after-market trading after it announced that the mid-stage study on pipeline candidate, sotatercept, in patients with pulmonary arterial hypertension (PAH) was successful.

The phase II study, PULSAR, is a randomized, double-blind, placebo-controlled trial designed to evaluate the efficacy and safety of sotatercept in PAH patients. The primary endpoint of the trial is the change from baseline in pulmonary vascular resistance (PVR) over a 24-week treatment period.

In the study, 106 patients were randomized to receive placebo, 0.3 mg/kg of sotatercept, or 0.7 mg/kg of sotatercept subcutaneously, every 21 days, in combination with stable background PAH-specific therapies over a 24-week treatment period.

The study results showed that the candidate demonstrated a statistically significant reduction in PVR, the trial’s primary endpoint, at week 24 versus placebo. PVR, as measured by right heart catheterization, is the resistance that the heart must overcome to pump blood through the pulmonary circulatory system.

The study also achieved statistically significant improvements in the key secondary endpoint of six-minute walk distance (6MWD) and other secondary endpoints, including amino-terminal brain natriuretic propeptide (NT-proBNP) and World Health Organization (WHO) functional class.

The candidate was generally well tolerated.

Moreover, 97 out of the 106 patients are currently participating in the 18-month extension period of the study.

Additional results will be presented later in the year.

Meanwhile, sotatercept is also being evaluated in another phase II study, SPECTRA, in patients with PAH.

Acceleron’s stock has rallied 33.6% in the past year against the industry ’s decline of 5.6%.