Exploratory post-hoc analysis of STELLAR shows potential of sotatercept to improve cardiovascular function

Interim results from SOTERIA open-label extension study represent longest safety and efficacy analysis of sotatercept to date; safety profile of sotatercept consistent with previous studies and efficacy improvements maintained after one year of therapy

Nine Merck-sponsored abstracts in PAH featured at European Respiratory Society (ERS) International Congress 2023

RAHWAY, N.J.--(BUSINESS WIRE)-- Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced new analyses from studies of sotatercept, Merck’s novel investigational activin signaling inhibitor biologic, for adults with pulmonary arterial hypertension (PAH) (WHO Group 1) at the European Respiratory Society (ERS) International Congress 2023. A new exploratory post-hoc analysis of right heart catheterization and echocardiography data from patients in the Phase 3 STELLAR study showed treatment with sotatercept for 24 weeks on top of background therapy reduced right heart size and improved right-ventricular (RV) function and hemodynamic status. This analysis was featured in an oral presentation, with simultaneous publication in the European Respiratory Journal. An interim analysis of the Phase 3 SOTERIA open-label extension study was also presented, representing the longest safety and efficacy analysis of sotatercept to date.

“There is an urgent need for new approaches to manage PAH, a rare, progressive, and ultimately life-threatening disease,” said Dr. Eliav Barr, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. “These latest data build on the clinically meaningful efficacy results from the STELLAR trial and support our belief that sotatercept has the potential to transform the treatment of PAH. PAH can strain the heart and lead to eventual right heart failure, so we are particularly encouraged by the exploratory analysis from STELLAR suggesting that treatment with sotatercept improved right heart size and function.”

Primary efficacy results from STELLAR, in which sotatercept on top of background therapy demonstrated a statistically significant and clinically meaningful improvement in 6-minute walk distance (6MWD) at 24 weeks and eight of nine secondary outcome measures, were presented at ACC.23/WCC and published in The New England Journal of Medicine. Merck submitted an application for regulatory approval of sotatercept to the U.S. Food and Drug Administration and plans to submit applications to additional regulatory agencies worldwide.

At ERS 2023, nine Merck-sponsored studies in PAH were presented. These include an oral presentation of a population health model predicting the long-term impact of sotatercept on morbidity and mortality in patients with PAH (#OA740).

Results from STELLAR hemodynamics and echocardiography analysis (Abstract #3111)

An exploratory post-hoc analysis from the STELLAR trial evaluated the effects of sotatercept on select hemodynamic parameters and right-ventricle (RV) function. The STELLAR trial enrolled 323 adults with PAH, randomized to receive sotatercept (n=163) or placebo (n=160), on top of background therapy. Participants with available data at screening and week 24 visits were included in this post-hoc analysis, which reported hemodynamic data from 298 participants and echocardiography data from 275 participants, representing 92% and 85% of total participants respectively. In the analysis, after 24 weeks, sotatercept was associated with meaningful improvements in certain measures of hemodynamic status and RV function.

Results from this exploratory analysis showed treatment with sotatercept compared to placebo, on top of background therapy, led to improvements from baseline in mean pulmonary arterial (PA) pressure (−13.9 mmHg), PA compliance (0.58 mL mmHg−1), pulmonary vascular resistance (−254.8 dyn·s·cm−5), mean right atrial pressure (−2.7 mmHg), mixed venous oxygen saturation (3.84%), PA elastance (−0.42 mmHg mL−1 beat−1), cardiac efficiency (0.48 mL beat−1 mmHg−1), RV work (−0.85 g·m) and RV power (−32.70 mmHg·L min−1). Echocardiography data showed improvements in the ratio of tricuspid annular plane systolic excursion to systolic pulmonary artery pressure (TAPSE/sPAP; 0.12 mm mmHg−1), end-systolic and end-diastolic RV areas (−4.39 cm2 and −5.31 cm2, respectively), tricuspid regurgitation and RV fractional area change (2.04% p440 m, NT-proBNP