Could a popular antiviral supercharge the pandemic?

Molnupiravir appears to be speeding SARS-CoV-2 evolution.

In nonhospitalized, unvaccinated adults with COVID-19, molnupiravir reduced hospitalization or death at 29 d.

SOURCE CITATION: Jayk Bernal A, Gomes da Silva MM, Musungaie DB, et al. Molnupiravir for oral treatment of Covid-19 in nonhospitalized patients. N Engl J Med. 2022;386:509-20. 34914868.

Lethal mutagenesis as an antiviral strategy.

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An updated practical guideline on use of molnupiravir and comparison with agents having emergency use authorization for treatment of COVID-19.

BACKGROUND AND AIMS: Molnupiravir is a newer oral antiviral drug that has recently received emergency use authorization (EUA) in USA, UK and India. We aim to conduct an update on our previous systematic review to provide practical clinical guideline for using molnupiravir in patients with COVID-19. METHODS: We systematically searched the electronic database of PubMed, MedRxiv and Google Scholar until January 5, 2022, using key MeSH keywords. RESULTS: Final result of phase 3 study in 1433 non-hospitalized COVID-19 patients showed a significant reduction in composite risk of hospital admission or death (absolute risk difference, -3.0% [95% confidence interval {CI}, -5.9 to -0.1%]; 1-sided P = 0.02) although with a non-significant 31% relative risk reduction (RRR). RRR for death alone was 89% (95% CI, 14 to 99; P-value not reported). Number needed to treat to prevent 1 death or 1 hospitalization or death composite appears to be closely competitive to other agents having EUA in people with COVID-19. However, cost-wise molnupiravir is comparatively cheaper compared to all other agents. CONCLUSION: Molnupiravir could be a useful agent in non-pregnant unvaccinated adults with COVID-19 who are at increased risk of severity including hospitalization. However, it is effective only when used within 5-days of onset of symptoms. A 5-days course seems to be safe without any obvious short-term side effects.

Human genetic risk of treatment with antiviral nucleoside analog drugs that induce lethal mutagenesis: The special case of molnupiravir.

This review considers antiviral nucleoside analog drugs, including ribavirin, favipiravir, and molnupiravir, which induce genome error catastrophe in SARS-CoV or SARS-CoV-2 via lethal mutagenesis as a mode of action. In vitro data indicate that molnupiravir may be 100 times more potent as an antiviral agent than ribavirin or favipiravir. Molnupiravir has recently demonstrated efficacy in a phase 3 clinical trial. Because of its anticipated global use, its relative potency, and the reported in vitro "host" cell mutagenicity of its active principle, ß-d-N4-hydroxycytidine, we have reviewed the development of molnupiravir and its genotoxicity safety evaluation, as well as the genotoxicity profiles of three congeners, that is, ribavirin, favipiravir, and 5-(2-chloroethyl)-2'-deoxyuridine. We consider the potential genetic risks of molnupiravir on the basis of all available information and focus on the need for additional human genotoxicity data and follow-up in patients treated with molnupiravir and similar drugs. Such human data are especially relevant for antiviral NAs that have the potential of permanently modifying the genomes of treated patients and/or causing human teratogenicity or embryotoxicity. We conclude that the results of preclinical genotoxicity studies and phase 1 human clinical safety, tolerability, and pharmacokinetics are critical components of drug safety assessments and sentinels of unanticipated adverse health effects. We provide our rationale for performing more thorough genotoxicity testing prior to and within phase 1 clinical trials, including human PIG-A and error corrected next generation sequencing (duplex sequencing) studies in DNA and mitochondrial DNA of patients treated with antiviral NAs that induce genome error catastrophe via lethal mutagenesis.

Molnupiravir for Oral Treatment of Covid-19 in Nonhospitalized Patients.

BACKGROUND: New treatments are needed to reduce the risk of progression of coronavirus disease 2019 (Covid-19). Molnupiravir is an oral, small-molecule antiviral prodrug that is active against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: We conducted a phase 3, double-blind, randomized, placebo-controlled trial to evaluate the efficacy and safety of treatment with molnupiravir started within 5 days after the onset of signs or symptoms in nonhospitalized, unvaccinated adults with mild-to-moderate, laboratory-confirmed Covid-19 and at least one risk factor for severe Covid-19 illness. Participants in the trial were randomly assigned to receive 800 mg of molnupiravir or placebo twice daily for 5 days. The primary efficacy end point was the incidence hospitalization or death at day 29; the incidence of adverse events was the primary safety end point. A planned interim analysis was performed when 50% of 1550 participants (target enrollment) had been followed through day 29. RESULTS: A total of 1433 participants underwent randomization; 716 were assigned to receive molnupiravir and 717 to receive placebo. With the exception of an imbalance in sex, baseline characteristics were similar in the two groups. The superiority of molnupiravir was demonstrated at the interim analysis; the risk of hospitalization for any cause or death through day 29 was lower with molnupiravir (28 of 385 participants [7.3%]) than with placebo (53 of 377 [14.1%]) (difference, -6.8 percentage points; 95% confidence interval [CI], -11.3 to -2.4; P = 0.001). In the analysis of all participants who had undergone randomization, the percentage of participants who were hospitalized or died through day 29 was lower in the molnupiravir group than in the placebo group (6.8% [48 of 709] vs. 9.7% [68 of 699]; difference, -3.0 percentage points; 95% CI, -5.9 to -0.1). Results of subgroup analyses were largely consistent with these overall results; in some subgroups, such as patients with evidence of previous SARS-CoV-2 infection, those with low baseline viral load, and those with diabetes, the point estimate for the difference favored placebo. One death was reported in the molnupiravir group and 9 were reported in the placebo group through day 29. Adverse events were reported in 216 of 710 participants (30.4%) in the molnupiravir group and 231 of 701 (33.0%) in the placebo group. CONCLUSIONS: Early treatment with molnupiravir reduced the risk of hospitalization or death in at-risk, unvaccinated adults with Covid-19. (Funded by Merck Sharp and Dohme; MOVe-OUT ClinicalTrials.gov number, NCT04575597.).