An update on a study investigating the efficacy of molnupiravir has suggested the oral antiviral drug is not as effective at preventing hospitalisations and deaths owing to COVID-19 as originally estimated.
An announcement on 26 November 2021 from Merck Sharp & Dohme (MSD) and Ridgeback Biotherapeutics — the developers of the drug — said that data were now available from all 1,433 of the participants enrolled in the MOVe-OUT study.
The study, which has not been peer reviewed, suggested that molnupiravir reduced the risk of hospitalisation or death from 9.7% in the placebo group (68/699) to 6.8% (48/709) in the molnupiravir group.
This was equivalent to an absolute risk reduction of 3.0% (95% confidence interval [CI]: 0.1, 5.9; nominal P-value=0.02) and a relative risk reduction of 30% (relative risk 0.70; 95% CI: 0.49, 0.99).
However, interim analysis results from 775 participants, reported on 1 October 2021, suggested that molnupiravir could reduce the risk of hospitalisation or death from COVID-19 by around 50%.
In the interim analysis, 7.3% of patients who received molnupiravir were either hospitalised or had died by day 29 compared with 14.1% of placebo-treated patients.
On 20 October 2021, the government announced that it had purchased 480,000 doses of the antiviral, which later became the first oral antiviral to be approved by the Medicines and Healthcare products Regulatory Agency (MHRA) for the treatment of COVID-19 in people who have mild-to-moderate COVID-19 and at least one risk factor for developing severe illness, such as obesity, older age (>60 years), diabetes mellitus or heart disease.
The two manufacturers maintained that the results still support the efficacy and overall favourable benefit-risk assessment of molnupiravir for the treatment of mild-to-moderate COVID-19 in adults at high risk for disease progression.
“Merck and Ridgeback Biotherapeutics have conducted a rigorous development program for molnupiravir and believe that molnupiravir has the potential to address a significant unmet medical need for an oral medicine for adults with COVID-19 who are at risk for progressing to severe COVID-19 and/or hospitalisation,” the companies said.
The Pharmaceutical Journal approached the MHRA for comment.