The first clinical trial in patients with monkeypox of an antiviral drug that could speed their recovery has begun in the UK.
The trial, known as Platinum, will explore whether Tecovirimat – a drug originally developed for smallpox – may reduce the length of time it takes for skin lesions and ulcers to heal.
It is thought the drug prevents the monkeypox virus from leaving infected cells, thereby stopping replication within the body, shortening the infectious period and allowing symptoms to clear faster.
But while Tecovirimat is already available for monkeypox patients admitted to hospital, it is not available for patients in the community, while experts say data is lacking on how effective the drug is.
Platinum is being run by the team who led the Recovery trial, which explored possible drugs for acute Covid, and has already begun recruiting patients. The team hopes results may be available before Christmas, saying Covid underscored the importance of running clinical trials to provide results during an outbreak.
“In a public health emergency the response is not about rushing around dishing out tablets that you think might work because that is seen to be doing something,” said Prof Sir Martin Landray, a joint chief investigator of the trial at the University of Oxford. “It’s about finding out as rapidly as you can, what actually does work, and then responding to the results that you see.”
Monkeypox outbreaks are under way in a host of countries where the disease is not endemic, including the UK and US, with cases largely seen among men who have sex with men. In July the World Health Organization declared monkeypox a public health emergency of international concern.
While many people shrug off the disease in a matter of weeks, it can cause severe symptoms and pain.
“About 10% of patients end up in hospital, sometimes with quite nasty complications,” said Prof Sir Peter Horby, the co-lead of the trial at the University of Oxford, noting these could include bacterial infections, brain inflammation and – rarely – death.
He said there was no proven effective treatment for monkeypox, but Tecovirimat was the “frontrunner” given it had been shown to be safe in healthy human volunteers, with animal studies suggesting it was effective against the disease.
The researchers hope to recruit at least 500 patients who have monkeypox but do not require hospital care for the study. Participants will be randomly allocated to receive either 600mg Tecovirimat tablets or placebo tablets that lack the active ingredient and, unaware of which they have been given, asked to take them twice daily for 14 days.
Participants can include children as well as adults and the trial will be open to people who are HIV positive or immunocompromised – with Horby noting the latter groups may be more at risk of severe disease and hence may have a greater benefit from the drug.
While the researchers said it was not clear how much Tecovirimat cost, they said if the drug was found to be safe and effective, they would work the government and others to make sure it was available to patients.
Dr Cheryl Walter, a virologist at the University of Hull who is not involved with the trial, said Tecovirimat had already undergone rigorous testing by many regulatory medicine agencies. She said the potential for a post-exposure drug that could help prevent further onward transmission came at a crucial time, given widespread shortages of the smallpox vaccine that can help prevent monkeypox.
In the UK, vaccine shortages have led to public health bodies trialling smaller doses of the vaccine in those at risk of exposure to monkeypox.
Jimmy Whitworth, a professor of international public health at the London School of Hygiene and Tropical Medicine, welcomed the study. “Doing trials during outbreaks is really important, otherwise it becomes very difficult or impossible to do clinical trials of diseases that are only seen in large number during outbreaks,” he told the Guardian.
“Monkeypox can cause distressing symptoms, even though it rarely kills, so any drug that can be demonstrated to significantly improve recovery will be welcome.”
