Merck (MSD) released new data analyses from two trials investigating sotatercept for adults with pulmonary arterial hypertension (PAH).
MSD presented the data at the European Respiratory Society (ERS) International Congress 2023 in Milan, Italy, on 9-13 September.
Sotatercept is a potential first-in-class activin signalling inhibitor. The investigational biologic is being investigated for the treatment of PAH, specifically Group 1 as defined by the World Health Organization (WHO).
MSD gained rights to sotatercept following the acquisition of Acceleron Pharma for $11.5bn in 2021. The drug is the subject of a licensing agreement with Bristol Myers Squibb.
Post-hoc STELLAR trial analysis
An exploratory post-hoc analysis from a Phase III STELLAR trial demonstrated that sotatercept led to various improvements in select haemodynamic parameters and right-ventricle (RV) function.
Alongside various measures, sotatercept reduced mean pulmonary arterial (PA) pressure, pulmonary vascular resistance, mean right atrial pressure, and improved PA compliance.
Echocardiography data showed sotatercept’s ability to improve the ratio of tricuspid annular plane systolic excursion to systolic pulmonary artery pressure, end-systolic and end-diastolic RV areas, tricuspid regurgitation and RV fractional area change.
The Phase III trial (NCT04576988) enrolled 323 adults with PAH and compared sotatercept to a placebo on top of a background therapy.
The study used a six-minute walk distance (6MWD) test as a primary endpoint. Other primary endpoints measured the number of participants with adverse events (AE) and those who discontinued the study treatment due to AE.
Data from ongoing SOTERIA trial
MSD also presented long-term data from the ongoing open-label SOTERIA trial (NCT04796337). The primary aim of the study is to evaluate the long-term safety and tolerability of sotatercept when added to a background PAH therapy.
At the data cut-off of 20 April 2023, sotatercept was generally well-tolerated with a similar profile that was observed in previous studies. However, treatment-emergent adverse events (TEAEs) occurred in 81.7% of participants, with 19.3% experiencing serious TEAEs.
Sotatercept showed continued efficacy of the treatment as a secondary objective, which is measured by a 6MWD, N-terminal pro-B-type natriuretic peptide (NT-proBNP), WHO functional class (FC), pulmonary vascular resistance, overall survival, and simplified French risk score.
Sotatercept in PAH
Sotatercept is the only PAH drug with a breakthrough therapy designation from the US Food and Drug Administration (FDA). As previously reported by Clinical Trials Arena, PAH lacks disease-modifying and curative therapies. As such, sotatercept is a welcomed drug in this disease space.
According to MSD’s Q2 2023 Earnings presentation, the company has completed an FDA submission for sotatercept based on the data from the Phase III STELLAR trial. GlobalData, the parent company of Clinical Trials Arena, estimates a regulatory approval in the US within 370 days from the filling, which should happen in August 2024.
