A cheap steroid called dexamethasone has been found to reduce the risk of death by up to one-third among coronavirus patients with severe respiratory complications, University of Oxford researchers have said.
Scientists working on the Recovery Trial found the drug could benefit patients on ventilators or oxygen, but had no effect on those who did not need help breathing.
“Based on these results, one death would be prevented by treatment of around eight ventilated patients or around 25 patients requiring oxygen alone,” researchers said in a statement.
Boris Johnson hailed the news as the "biggest breakthrough yet" in the battle against coronavirus and confirmed that the UK had enough stocks of the drug to cope if there is a second spike in cases.
He told the daily Downing Street press conference: "I am proud of these British scientists, backed by UK government funding, who have led the first robust clinical trial anywhere in the world to find a coronavirus treatment proven to reduce the risk of death."
The prime minister confirmed that the drug would be made available on the NHS, adding: "We've taken steps to ensure we have enough supplies, even in the event of a second peak."
The government has stockpiled 200,000 courses of dexamethasone since March, and placed oral and injection solutions on a list of medicines banned for export from the UK at midnight on Tuesday. Tablets were restricted in April.
In a statement, the Department for Health said the export ban was designed to deter companies from buying supplies of the drug meant for the UK and reselling them at higher prices abroad.
Experts said a randomised group of 2,104 patients were given 6mg of dexamethasone per day for 10 days, while another group of 4,321 were given normal treatment. Dexamethasone reduced deaths by one-fifth in patients on oxygen feeds and by one-third in those who needed a ventilator to breathe, preliminary results showed.
Peter Horby, professor of emerging diseases and global health at Oxford University, one of the trial's chief investigators, said the steroid had been around for more than 60 years and was regarded by some as a "very boring drug" but the findings were "remarkable".
"We've looked at the numbers and if we treat eight patients in intensive care with this drug, we will save one life," he told the press conference.
"The total cost of treating eight patients is only about £40. So this really remarkable and we are extremely pleased with this result."
Asked when it could begin being used, Prof Horby said: "It’s in the cupboards…. It can be done this evening.”
Chief scientific adviser Sir Patrick Vallance said it was "the start of something important" as dexamethasone was the first medicine to reduce chances of death in any group of patients.
But asked if the breakthrough meant there was no need to fear a second spike, he said that, while helpful, the new drug was “certainly not an effect such as would make us think we don’t have to worry about other measures.”
Martin Landray, professor of medicine and epidemiology at Oxford University, another of the trial’s chief investigators, said: “These preliminary results from the Recovery Trial are very clear – dexamethasone reduces the risk of death among patients with severe respiratory complications.
“Covid-19 is a global disease – it is fantastic that the first treatment demonstrated to reduce mortality is one that is instantly available and affordable worldwide.”
Chris Whitty, England’s chief medical officer, said that it was “the most important trial result for COVID-19 so far”.
“Significant reduction in mortality in those requiring oxygen or ventilation from a widely available, safe and well-known drug. Many thanks to those who took part and made it happen. It will save lives around the world,” he said.
Researchers are now working to publish the full details of their results.
Nick Cammack, of the Wellcome health foundation, called for the drug to be made available to anyone who needed it around the world, whether they could afford to pay for it or not.
“It is highly affordable, easy to make, can be scaled up quickly and only needs a small dosage,” he added. “This is extremely promising news and a significant step forward, but we still have a long way to go. To end this pandemic, we still need better diagnostics to detect, medicines to treat and vaccines to prevent Covid-19.”