First clinical trials of monkeypox treatment Tpoxx start in UK

Phase will assess whether the Siga Technologies drug can alleviate symptoms

Health officials in the UK licensed Tpoxx earlier this year based on results from initial studies in animals. Reuters
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The first clinical trials of the Tpoxx monkeypox treatment have started in the UK

Academics from the University of Oxford who were behind the Covid Recovery trial have launched the Platinum trial to assess whether an antiviral drug can alleviate monkeypox symptoms.

The researchers are hoping to recruit 500 people from around the UK to join the trial to test whether Tecovirimat ― also known as Tpoxx ― can help reduce the amount of time people are sick.

The drug, which was created to treat smallpox, works by preventing the virus from leaving the infected cell, which stops the replication of the virus within the body.

Health officials in the UK licensed the drug earlier this year based on results from initial studies in animals and safety evidence from human volunteers.

It is currently offered to patients with severe complications who are being treated in hospital.

But to date there have been no clinical trials to confirm whether Tpoxx can help monkeypox patients recover from the disease.

The Platinum trial will be the first randomised controlled trial of a treatment for monkeypox in humans in the world.

This means that half of the participants — who will have a confirmed diagnosis of monkeypox but not in such a serious condition that they need hospital care — will be given Tpoxx, while the other half will be given a placebo.

Most patients with monkeypox will be eligible to enrol on the trial which will involve them taking the medication, or the placebo, twice a day for 14 days.

They will be followed up for a month to assess whether taking the drug reduces symptoms — including the length of time people have painful skin lesions — or whether it could reduce the amount of time people stay in isolation.

Researchers will also examine whether the drugs can reduce the amount of time people test positive for the virus.

While vaccines developed for smallpox may reduce the risk of catching monkeypox, there are currently no proven therapeutics to speed recovery in those who develop the disease.

The study, commissioned and funded by the National Institute for Health and Care Research, recruited its first participant on Friday.

Sir Peter Horby, professor of emerging infections and global health at the University of Oxford, said monkeypox is a "distressing and sometimes dangerous infection".

"For the benefit of current and future patients worldwide who have been diagnosed with monkeypox, we need definitive evidence that Tecovirimat is safe and effective," he said.

"Although the early data on Tecovirimat are promising, only a randomised clinical trial will provide the level of evidence we need to treat patients with confidence. Platinum will provide that evidence."

Vaccines first line of defence

While Tpoxx is seen as a valuable addition to the anti-monkeypox ordnance, the UK government considers the treatment as being adjunctive to vaccines.

On Monday, the UK Health Security Agency launched a pilot programme offering eligible patients smaller doses of the vaccine amid global shortages of the shot.

"Vaccines remain our best defence against the spread of monkeypox — we urge all those eligible to come forward when contacted, and report any symptoms," said Public Health Minister Maggie Throup.

Since the start of the outbreak there have been more than 3,000 UK cases, with most of these detected in England.

Updated: August 24, 2022, 1:10 PM