Molnupiravir, which is consumed orally as a pill, will be given twice a day to people who have recently tested positive for Covid and have at least one risk factor for developing severe illness, such as obesity, being over the age of 60, diabetes or heart disease.
The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) said the drug is safe and effective in people with mild to moderate Covid who are at extra risk from the virus. It is the first regulator in the world to approve the drug for public use.
The government has secured enough supplies of the drug to treat 480,000 people, with the order set to be delivered to the UK by the end of the year.
Health secretary Sajid Javid said: “Today is a historic day for our country, as the UK is now the first country in the world to approve an antiviral that can be taken at home for Covid-19. This will be a game-changer for the most vulnerable and the immunosuppressed, who will soon be able to receive the ground-breaking treatment.
“We are working at pace across the government and with the NHS to set out plans to deploy molnupiravir to patients through a national study as soon as possible.”
Molnupiravir, manufactured by Ridgeback Biotherapeutics and Merck Sharp & Dohme (MSD), works by interfering with the replication of Sars-CoV-2 after it’s entered human cells. This prevents it from multiplying, keeping virus levels low in the body and therefore reducing the severity of the disease.
The MHRA said the drug should be taken as soon as possible following a positive Covid-19 test and within the first five days.
Data from Merck’s clinical trial show that the drug, which was first developed to treat influenza, reduces the risk of hospital admission and death from Covid by 50 per cent in patients recently infected with the virus.
Some 775 people with Covid took part in the study. Among the half of patients taking molnupiravir twice a day, 7.3 per cent were admitted to hospital over the course of 30 days. This compares with 14.1 per cent of the second group of patients who were given a placebo pill.
There were no deaths in the molnupiravir group, but eight patients who were given a placebo in the trial later died of Covid.
Evidence from a separate study suggests the drug is not effective at treating people already hospitalised with severe Covid.
In the UK, there are two other approved ways of treating Covid-19: using steroids, such as dexamethasone, or by administering lab-designed antibodies intravenously.
The MHRA’s chief executive, Dr June Raine, described molnupiravir as “another therapeutic to add to our armoury against Covid-19”.
“It is the world’s first approved antiviral for this disease that can be taken by mouth rather than administered intravenously,” she said. “This is important, because it means it can be administered outside of a hospital setting, before Covid-19 has progressed to a severe stage.”
The UK has also ordered 250,000 courses of a second antiviral drug developed by Pfizer. Large-scale trials are still underway to determine the effectiveness of this treatment, though hopes are high that it will prove to be a success.