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expert reaction to MHRA Conditional Marketing Authorisation of molnupiravir

It has been announced that the first oral antiviral for COVID-19, molnupiravir, has been approved by The Medicines and Healthcare products Regulatory Agency (MHRA).


Prof Penny Ward, Independent Pharmaceutical Physician, Visiting Professor in Pharmaceutical Medicine at King’s College London, said:

“Very welcome news today that the MHRA have issued a Conditional Marketing Authorisation for molnupiravir, the first oral antiviral which has been shown to be an effective treatment for COVID. In the clinical trial, molnupiravir reduced hospitalisations and deaths in a population of patients at risk of more severe outcomes by ~50% (from 14.1% to 7.3%). Importantly, no deaths were reported among molnupiravir recipients compared to 8 (2.1%) in placebo recipients. The clinical trial population enrolled were unvaccinated adults >18 years of age with at least one additional risk factor for disease progression (60 years of age or older, diabetes, obesity (BMI >30), chronic kidney disease, serious heart conditions, chronic obstructive pulmonary disease, or active cancer). Treatment started within 5 days of onset of symptoms. If these outcomes are replicated in the UK population, then the number of cases requiring hospital admission could be halved and the number of deaths greatly reduced. Molnupiravir is a prodrug that is metabolised to the nucleoside analogue N-hydroxycytidine (NHC) which distributes into cells where it forms an active nucleoside 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 causes an accumulation of errors in the viral genome which stops the virus replicating. This mechanism of action has some limitations and the drug cannot be given to pregnant women due to the risk of damaging an unborn baby. The NHS has yet to inform us on how this product may be distributed to patients; comments made by Mr Javid today suggest that it may be made available via a clinical trial, presumably to investigate its effectiveness in vaccinated patients with breakthrough infections, as the original study incorporated unvaccinated adults. In addition, as the UK has ordered 480,000 treatment courses, if given to everyone becoming unwell this supply would not last very long given the 40,000+ current daily case rate. For this reason it seems likely that use will be restricted for use by those at highest risk of disease complications eg older adults with heart, lung or kidney disease, diabetes or cancer. The announced price of this drug in the US is $713 (about £520), making it more than 20 times more expensive than Tamiflu which the UK stockpiled for use in an influenza pandemic. The NHS supply price has not been announced. Its manufacturer, Merck, has announced plans to produce 10 million courses of the drug in 2021 which – given the likely worldwide demand – is an extremely limited supply. Other antiviral treatments already approved in the UK include the intravenous monoclonal antibody combination from Regeneron, which is limited to hospital use, and remdesivir, another intravenous agent which was recently shown to be effective in an outpatient setting if started within 5 days of symptom onset and given for 3 days. Perhaps the NHS might also investigate whether a 3 day course of molnupiravir is as effective as a 5 day course, in which case the limited supply available might be stretched further.”



All our previous output on this subject can be seen at this weblink:



Declared interests

Prof Penny Ward: “I am semi-retired, but I am owner/Director of PWG Consulting (Biopharma) Ltd a consulting firm advising companies on drug and device development. Between December 2016 and July 2019 I served as Chief Medical Officer of Virion Biotherapeutics Ltd, a company developing antiviral treatments for respiratory viral diseases. Previous employee of Roche, makers of tocilizumab (anti IL6 antibody) and CMO of Novimmune, makers of empalumab (anti IFN gamma antibody).”

None others received.

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