Molnupiravir photo
Photo source: BBC
Last updated 2 December 2021. Information on this topic is rapidly changing and may render the following incomplete or inaccurate.
KEY POINTS
- Molnupiravir (Lagevrio, MK-4482, EIDD-2801) is a ribonucleoside analog antiviral medication that inhibits the replication of SARS-CoV-2
- Molnupiravir is a prodrug that is metabolised to the ribonucleoside analogue N-hydroxycytidine (NHC) which distributes into cells where it is phosphorylated to form the pharmacologically active ribonucleoside triphosphate (NHC-TP). NHC-TP acts by a mechanism known as viral error catastrophe. NHC-TP incorporation into viral RNA by the viral RNA polymerase, results in an accumulation of errors in the viral genome leading to inhibition of replication.
- Molnupiravir was approved for use in the UK on 4 November 2021 to treat mild to moderate coronavirus disease 2019 (COVID-19) in adults with a positive SARS-COV-2 diagnostic test and who have at least one risk factor for developing severe illness
- Should be administered as soon as possible after a diagnosis of COVID-19 has been made and within 5 days of symptom onset
- Comes in a 200 mg capsule for oral administration, to be given as 800 mg twice daily x5 days
- No renal or hepatic dose adjustment required
- Take with or without food
- Drug-drug interactions are unlikely
- Pregnancy data is lacking, use during pregnancy is not recommended
- The most commonly reported adverse reactions have been diarrhea (3%), nausea (2%), dizziness (1%) and headache (1%)
- Molnupiravir is expected to gain FDA Emergency Use Authorization in December 2021
- FDA held an Advisory Committee Meeting to Discuss Merck and Ridgeback’s EUA Application for COVID-19 Oral Treatment
- Voted 13 yes, 10 no
- Expected that the cost of molnupiravir will be about $700 per course (similar to paxlovid from Pfizer), but information on who pays is not yet available
- FDA held an Advisory Committee Meeting to Discuss Merck and Ridgeback’s EUA Application for COVID-19 Oral Treatment
- Merck reports that: “At the Interim Analysis, 7.3 Percent of Patients Who Received Molnupiravir Were Hospitalized Through Day 29, Compared With 14.1 Percent of Placebo-Treated Patients Who were Hospitalized or Died.”
- Publicly available clinical data for clinicians to review are currently lacking for molnupiravir
- Some current questions about molnupiravir include:
- How effective is molnupiravir?
- Is molnupiravir safe?
- Will molnupiravir work against SARS-CoV-2 variants?
- Will viral resistance in SARS-CoV-2 arise with molnupiravir?
- How will people access molnupiravir?
RESOURCES
- Regulatory approval of Lagevrio (molnupiravir) – UK Government Website
- November 30, 2021: Antimicrobial Drugs Advisory Committee Meeting Announcement – FDA
- Unmet need for COVID-19 therapies in community settings – Lancet ID
- β-D–N4-hydroxycytidine Inhibits SARS-CoV-2 Through Lethal Mutagenesis But Is Also Mutagenic To Mammalian Cells – JID
- COVID antiviral pills: what scientists still want to know – NATURE news explainer
- Merck and Ridgeback’s Molnupiravir, an Oral COVID-19 Antiviral Medicine, Receives First Authorization in the World News Release
- Merck and Ridgeback’s Investigational Oral Antiviral Molnupiravir Reduced the Risk of Hospitalization or Death by Approximately 50 Percent Compared to Placebo for Patients with Mild or Moderate COVID-19 in Positive Interim Analysis of Phase 3 Study News Release
