New treatments are warranted to limit the risk of progression of coronavirus disease 2019 (Covid-19). Molnupiravir, an antiviral prodrug, has shown its potential activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

A phase 3, double-blind, randomized, placebo-controlled trial evaluated molnupiravir for its efficacy and safety. The treatment was initiated within 5 days of onset of signs or symptoms in nonhospitalized, unvaccinated adults with mild-to-moderate, laboratory-confirmed Covid-19, with not less than one risk factor for severe Covid-19 illness. Subjects were randomized to receive either 800 mg of molnupiravir or a placebo in a BD dose for 5 days. Efficacy was evaluated by the incidence of hospitalization or death at day 29; safety was evaluated by the incidence of adverse events. 

A planned interim analysis was done when half of 1550 participants were followed up till day 29.

The following observations were made-

• 1433 participants were enrolled on the study.
• 716 and 717 subjects received molnupiravir and placebo respectively. 
• Baseline characteristics were similar in the two groups except for the gender. 
• The interim analysis demonstrated molnupiravir to be superior to placebo as the risk of hospitalization for any cause or death through day 29 was lower with molnupiravir (7.3%) than with placebo (14.1%).
• Also, molnupiravir group had less hospitalization or death through day 29 than the placebo group (6.8% vs. 9.7%). 
• Results of subgroup analyses were also similar to these results. However, in some subgroups, like patients with previous SARS-CoV-2 infection, those with low baseline viral load, and those with diabetes, the point estimate for the difference favored placebo. 
• The molnupiravir group and the placebo group reported 1 and 9 death respectively, through day 29. 
• 30.4% of the participants in the molnupiravir group and 33.0% in the placebo group reported adverse events.

Thus it was concluded that early treatment with molnupiravir can reduce the risk of hospitalization or death in at-risk, unvaccinated adults with Covid-19. 

SOURCE- Jayk Bernal A, Gomes da Silva MM, Musungaie DB, Kovalchuk E, Gonzalez A, Delos Reyes V. et al. Molnupiravir for Oral Treatment of Covid-19 in Nonhospitalized Patients, New England Journal of Medicine, 2012. https://www.nejm.org/doi/full/10.1056/NEJMoa2116044