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MSD has put a stop to its Phase III HYPERION study investigating its pulmonary arterial hypertension (PAH) treatment Winrevair after the therapy provided positive results from another Phase III trial.
The company confirmed that it has decided to end the placebo-controlled HYPERION trial (NCT04811092) examining Winrevair (sotatercept-csrk) after results from the ZENITH trial (NCT04896008) met its primary endpoint at interim analysis.
Merck Research Laboratories’ chief medical officer Eliav Barr said: “Based on the strong, positive interim efficacy data from the ZENITH trial, as well as the totality of available Winrevair data, we concluded that it would not be ethical to continue the HYPERION study.”
The HYPERION study was a global, double-blind trial that enrolled approximately 300 patients with PAH at intermediate or high risk of disease progression. In that trial the primary endpoint involved time to clinical worsening (TTCW) as measured by the first confirmed morbidity or mortality event.
Winrevair was approved by the US Food and Drug Administration (FDA) in March 2024 following results from the STELLAR (NCT04576988) trial and has since been approved in 38 other countries. In the trial, the primary endpoint was determined exercise capacity, measured by way of patients achieving a six-minute walk distance (6MWD) at least 24 weeks after starting treatment.
Vallerie McLaughlin, cardiovascular professor at the University of Michigan and investigator in the ZENITH and HYPERION trials, detailed that a loss of certainty over placebo meant the committee had chosen to end the study.
McLaughlin said: “After closely reviewing the robust efficacy data across a broad spectrum of patients evaluated in the Winrevair clinical development programme, the steering committee has unanimously concluded that the HYPERION study has lost clinical equipoise and should be stopped early.”
Patients who were previously enrolled on the HYPERION study will be offered the chance to access the treatment through the Phase III SOTERIA (NCT04796337) open-label extension (OLE) study.
Research by GlobalData found that MSD earned $538m last year from Winrevair. That figure is estimated to significantly jump to $1.8bn by the end of this year, which would provide Winrevair with blockbuster status. The drug is set to reach global market sales of $6.2bn by the end of 2030.
GlobalData is the parent company of Clinical Trials Arena.