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How effective is Lagevrio (molnupiravir) for COVID-19?

Medically reviewed by Melisa Puckey, BPharm. Last updated on Dec 14, 2023.

How effective is Merck's molnupiravir COVID-19 capsule?

Official answer

by Drugs.com

Molnupiravir (Lagevrio, MK-4482, EIDD-2801) is Merck's antiviral capsule that has been used successfully in studies to treat mild to moderate COVID-19, reducing risk of hospitalization and death.

A recent update of the MOVe-OUT study molnupiravir showed a relative risk reduction of 30% for hospitalization or death, and the relative risk reduction death was 89%, when molnupiravir compared to placebo.

Risk of hospitalization or death

  • Placebo group 9.7% (68 out of 699).
  • Molnupiravir group 6.8% (48 out of 709).
  • Relative risk reduction of hospitalization or death was 30% for mulnupiravir when compared to placebo.


Risk of death

  • Placebo group 1.3% (9 out of 699).
  • Molnupiravir group 0.1% (1 out of 709).
  • Relative risk reduction of death was 89% for molnupiravir when compared to placebo.

Side effects were similar in the two groups with molnupiravir group having 35.0% and the placebo group had 39.6% of patients reporting side effects.

These results show that molnupiravir works effectively and the study also demonstrated a positive benefit-risk balance for the treatment of mild to moderate COVID-19 in adults at high risk for disease progression.

Is Molnupiravir an FDA approved medicine?

Molnupiravir is not an FDA approved medicine.

On December 23, 2021 the FDA issued an Emergency Use Authorization (EUA) for molnupiravir as a treatment of COVID-19:

  • for patients 18 years and older,
  • who are at risk developing severe illness, including hospitalization or death,
  • patients must have had positive SARS-CoV-2 viral test and,
  • they must also be unable to use alternative COVID-19 treatment options, due to being inaccessible or being clinically inappropriate.

How does molnupiravir work?

  • Molnupiravir is an oral antiviral medicine that works by decreasing the ability of the virus (SARS-CoV-2) to make copies of itself.
  • It does this by joining into the virus’s RNA which creates errors and reduces the virus’s ability to replicate.

Does molnupiravir work against Omicron?

  • The Phase 3 MOVe-OUT study showed molnupiravir worked well against the three most common variants of the time Delta, Mu, and Gamma and Dr. Dean Y. Li, president of Merck Research Laboratories has said that more recent preclinical evidence indicates that molnupiravir has antiviral activity against Omicron.

Related questions

Can molnupiravir prevent COVID-19?

  • Molnupiravir is not authorized for use for pre-exposure or post-exposure prophylaxis for prevention of COVID-19.
  • MOVe-AHEAD is a study looking at whether molnupiravir works to prevent COVID-19 when taken after you have been in contact with COVID-19. This is called post-exposure prophylaxis and is when you take molnupiravir after you have been exposed to a person with COVID-19 to help build up protection against COVID-19, and lower the chance of developing severe COVID-19 or dying.
  • The MOVe-AHEAD study is ongoing so we need to wait for the study to be complete or interim results become available before we know if or how well molnupiravir prevents COVID-19. Therefore molnupiravir is NOT authorized to prevent COVID-19.

How do you take molnupiravir (Largevrio) ?

  • Molnupiravir is to be used by adults with mild to moderate COVID-19 , who have had a positive test for COVID-19 and be at risk of developing severe COVID-19 illness.
  • Start molnupiravir as soon as possible after COVID-19 diagnosis and within 5 days of symptoms starting.
  • Take 800mg (four 200mg capsules) every 12 hours for 5 days.
  • Molnupiravir can be taken with or without food.
  • Swallow the capsules whole with a glass of fluid. Do not open, crush or chew the capsules.
  • Molnupiravir is a single medicine that does not need to be taken in conjunction with another medicine.


Bottomline:

  • Molnupiravir is an investigational antiviral capsule use against COVID-19, it has a relative risk reduction of 30% for hospitalization or death, and a relative risk reduction of death of 89% when compared to placebo,
  • Molnupiravir has been issued and Emergency Use Authorization to be used to treat mild to moderate COVID-19 in patients at risk of developing severe COVID-19 illness.
  • Lagevrio should be started within 5 days of symptoms starting. The dose is 800mg (four 200mg capsules) every 12 hours for 5 days, and can be taken with or without food.
References
  • EMC: Lagevrio 200mg hard capsules: [Accessed December 20, 2021] https://www.medicines.org.uk/emc/product/13044/smpc#gref
  • Merck and Ridgeback Biotherapeutics Provide Update on Results from MOVe-OUT Study of Molnupiravir, an Investigational Oral Antiviral Medicine, in At Risk Adults With Mild-to-Moderate COVID-19. [Accessed December 20, 2021] https://www.merck.com/news/merck-and-ridgeback-biotherapeutics-provide-update-on-results-from-move-out-study-of-molnupiravir-an-investigational-oral-antiviral-medicine-in-at-risk-adults-with-mild-to-moderate-covid-19/
  • Merck and Ridgeback Statement on Positive FDA Advisory Committee Vote for Investigational Oral Antiviral Molnupiravir for Treatment of Mild to Moderate COVID-19 in High Risk Adults [Accessed December 20, 2021] https://www.drugs.com/clinical_trials/merck-ridgeback-statement-positive-fda-advisory-committee-vote-investigational-oral-antiviral-19828.html
  • Merck and Ridgeback Biotherapeutics Announce Initiation of Pivotal Phase 3 MOVe-AHEAD Study Evaluating Molnupiravir for Post-Exposure Prophylaxis of COVID-19 Infection. [Accessed December 20, 2021] https://www.merck.com/news/merck-and-ridgeback-biotherapeutics-announce-initiation-of-pivotal-phase-3-move-ahead-study-evaluating-molnupiravir-for-post-exposure-prophylaxis-of-covid-19-infection/
  • FACT SHEET FOR HEALTHCARE PROVIDERS: EMERGENCY USE AUTHORIZATION FOR MOLNUPIRAVIR [Accessed December 24, 2021] https://www.fda.gov/media/155054/download
  • Coronavirus (COVID-19) Update: FDA Authorizes Additional Oral Antiviral for Treatment of COVID-19 in Certain Adults: [Accessed December 24, 2021] https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-additional-oral-antiviral-treatment-covid-19-certain?utm_campaign=Coronavirus+%28COVID-19%29+Update%3A+December+23%2C+2021&utm_medium=email&utm_source=govdelivery
  • FDA Gives OK to Merck's Antiviral At-Home COVID Pill: [Accessed December 24, 2021] https://www.drugs.com/news/fda-gives-ok-merck-s-antiviral-home-covid-pill-102478.html

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