Merck & Co. has unveiled new clinical data on sotatercept, reinforcing the drug candidate’s safety and efficacy in the treatment of pulmonary arterial hypertension (PAH) as it awaits a crucial FDA decision following its $11.5 billion acquisition of Acceleron Pharma. Nearly a year ago, Merck initiated the process for sotatercept’s regulatory approval by demonstrating its positive impact on outcomes in adults with PAH through linking the activin receptor type IIA-Fc fusion protein. Since then, Merck has continued to release additional data while preparing regulatory submissions, including to the FDA.
Merck has chosen the European Respiratory Society International Congress 2023 as the platform to share fresh findings from the pivotal phase 3 trial and an interim analysis of an open-label extension.
The phase 3 trial data involve an exploratory post hoc analysis focusing on sotatercept’s effects on cardiovascular function. Merck has correlated the drug with improvements in hemodynamic status and right-ventricle (RV) function. Notable improvements include reductions in mean pulmonary arterial pressure, enhanced cardiac efficiency, and increased RV power compared to a placebo. While these analyses are exploratory and post hoc, Dr. Vallerie McLaughlin, a professor of medicine at the University of Michigan, expressed optimism about the potential of sotatercept to positively impact certain aspects of right heart function, reinforcing its role in treating PAH.
“This is the first clinical evidence suggesting that sotatercept may positively impact certain measures of right heart function and dimensions. This is encouraging and further supports the primary results from the STELLAR analysis, underscoring the potential of sotatercept to play a critical role in the treatment of PAH.”
– Dr. Vallerie McLaughlin, professor of medicine at the University of Michigan
Merck has also presented early results from an ongoing open-label extension study designed to assess the long-term effects of sotatercept. As of April 20, the study had enrolled 409 participants, tracking them for a median of 462 days, which includes their exposure to sotatercept in earlier trials.
In terms of safety, the data align with previous studies, with 19.3% of participants experiencing serious treatment-emergent adverse events. Importantly, only 1.5% of participants withdrew or passed away due to these events. Additionally, 22.7% of subjects developed telangiectasia, a condition characterized by dilated or broken blood vessels in the skin. On the efficacy front, improvements on the six-minute walk test and a biomarker were largely maintained.
Merck’s comprehensive data presentation underscores the growing body of evidence supporting sotatercept’s safety and efficacy in the treatment of PAH. These findings come at a crucial juncture as Merck awaits regulatory decisions that could pave the way for sotatercept to become a key player in addressing this challenging medical condition.
