The newest potential “miracle” treatment for Covid-19 to be touted won praise for its performance in a clinical study carried out by the University of Oxford. The university said it stopped its trial with the 60-year-old steroid drug early, due to the unexpected success of the treatment.

In the research comparing more than 2,000 patients who needed breathing assistance to a control arm of over 4,000 patients, those on ventilators and treated with dexamethasone were shown to be 35% less likely to die. Patients receiving oxygen only were 20% less likely to die. There was no benefit shown among patients who didn’t need breathing support.

Based on the results, the researchers said dexamethasone could prevent one death among eight ventilated patients and around one death for every 25 patients who required oxygen alone.

“While this study suggests dexamethasone only benefits severe cases, countless lives will be saved globally,” said Nick Cammack, Covid-19 therapeutics accelerator lead at Wellcome, the medical research philanthropy group.

The dexamethasone trial was part of a larger study called Recovery, comparing a number of potential coronavirus treatments in an attempt to quickly identify those that are most effective. More than 11,500 patients have been enrolled from over 175 National Health Service hospitals across the UK.

Britain has the highest death toll from the virus in Europe and about one-tenth of the global total of fatalities. The government now plans to roll out the treatment across the National Health Service (NHS), and health minister Matt Hancock said it has stockpiled more than 200,000 courses of dexamethasone.

A generic for decades, the steroid currently made by Merck & Co and Mylan, and prescribed for ailments ranging from asthma to allergies as well as to alleviate nausea in chemotherapy patients, costs £5 or less for a course of treatment, reports say.

With a number of anti-inflammatories currently being studied worldwide to help virus patients cope with the immune system’s powerful overreaction called cytokine storm, the British government is in particularly keen to find need a promising treatment.

Trials with chloroquine and hydroxychloroquine have been halted by British authorities since the US Food and Drug Administration this week revoked emergency-use authorization the drugs.

Beyond being dangerous for people with underlying cardiac risks, the US health agency said the two drugs could also interfere with the effectiveness of Gilead’s remdesivir, which is also being tested as a Covid treatment.

In comparison with other potentially useful anti-inflammatory drugs such as Roche’s Actemra and Gilead Sciences’s remdesivir, dexamethasone is said to be widely available and uncomplicated to manufacture.

Some commentators have warned of premature euphoria about the prospects for dexamethasone, however, as only limited data at this point has been released. Others said that if it is effective at all, its sheer affordability would be a plus.

After the debacle with hydroxychloroquine, the World Health Organization (WHO) has urged caution on rushing into treatment of patients with dexamethasone. The organization said its officials are looking at other research on dexamethasone and “will come to a conclusion on clinical advice to countries.“