Merck Oral Antiviral Reduces by Half the Risk of COVID-19 Hospitalization, Death in Vulnerable Adults

The positive results of the Merck MOVe-OUT phase 3 interim analysis of molnupiravir have led to an early halt to study recruitment, the company said Friday.

An investigational oral antiviral being developed by Merck and Ridgeback Biopharmaceuticals significantly reduced the risk of hospitalization or death among at risk non-hospitalized adults with mild-to-moderate infection with SARS-CoV-2, according to a company announcement made Friday, October 1, 2021.

The findings come from a planned interim analysis of the phase 3 MOVEe-OUT trial that is comparing the new oral agent molnupiravir to placebo. The companies announced that molnupiravir reduced the risk of hospitalization or death by approximately half.

Of the patients who received molnupiravir, 7.3% (28/385) were either hospitalized or died through study Day 29 vs 14.1% of patients given placebo (53/377); p=0.0012.

The company reports that there were no deaths among patients in the molnupiravir group through Day 29, but 8 deaths were reported in patients who received placebo.

The most common risk factors for poor disease outcome included obesity, older age (>60 years), diabetes, and heart disease.

Recruitment into the study is being halted early for positive outcomes, based on the recommendation of an independent Data Monitoring Committee and in consultation with the US Food and Drug Administration (FDA), according to the statement.

“More tools and treatments are urgently needed to fight the COVID-19 pandemic, which has become a leading cause of death and continues to profoundly affect patients, families, and societies and strain health care systems all around the world. With these compelling results, we are optimistic that molnupiravir can become an important medicine as part of the global effort to fight the pandemic,” said Merck chief executive officer and president Robert M. Davis, in the press release.

“With the virus continuing to circulate widely, and because therapeutic options currently available are infused and/or require access to a healthcare facility, antiviral treatments that can be taken at home to keep people with COVID-19 out of the hospital are critically needed,” added Wendy Holman, chief executive officer of Ridgeback Biotherapeutics.

The MOVe-OUT trial (NCT04575597) was a global Phase 3, randomized, placebo-controlled, double-blind, 170-site study of non-hospitalized adult patients with laboratory-confirmed mild-to- moderate COVID-19 who had at least 1 risk factor for poor disease outcome and whose symptoms began within 5 days of study randomization. The primary objective of the study is to evaluate the efficacy of molnupiravir vs placebo as assessed by the percentage of participants who are hospitalized and/or die from the time of randomization through Day 29.

Findings from this planned interim analysis were based on data from 775 patients enrolled in the phase 3 trial on or before August 5, 2021. More than 90% of the full recruitment sample size (n=1550) had been enrolled when recruitment was stopped.

The risk of hospitalization and/or death among patients taking molnupiravir was reduced across all key subgroups studied, according to the Merck statement. Molnupiravir efficacy was not affected by timing of symptom onset or underlying risk factor. The company also reports that when available viral sequencing data were analyzed (from ~40% of participants), molnupiravir demonstrated consistent efficacy across the Gamma, Delta, and Mu SARS-CoV-2 variants which have accounted for nearly 80% of evaluable cases in the trial.

The incidence of any adverse event was comparable between study groups as was incidence of drug-related adverse events, the press release states. Discontinuation of study therapy related to an adverse event was lower in the molnupiravir group vs the placebo group. 

“We are very encouraged by the results from the interim analysis and hope molnupiravir, if authorized for use, can make a profound impact in controlling the pandemic," said Ridgeback's Holman.

According to the company press statement, Merck plans to submit an application for Emergency Use Authorization (EUA) for molnupiravir to the FDA as soon as possible and to submit marketing applications to other regulatory bodies worldwide.