British researchers say an inexpensive and commonly available medicine can help save the lives of those seriously ill with the coronavirus—the first time a drug has been found to cut deaths from the disease. Scientists found that the treatment, a steroid called dexamethasone, reduced deaths among those on ventilators by one-third and among those on oxygen by one-fifth. “This is the only drug so far that has been shown to reduce mortality—and it reduces it significantly,” chief investigator Peter Horby, from Oxford University, tells BBC.com. “It’s a major breakthrough.” The drug, which costs less than $1 per day of treatment, is a workhorse steroid widely used to treat inflammation in people with conditions such as asthma and arthritis. Doctors suspect it is effective against Covid-19 because it prevents some of the potentially fatal organ damage caused by “cytokine storms”—when the immune system goes into overdrive as it tries to fight the coronavirus, and begins attacking the body. The randomized, controlled clinical trial—the gold standard for medical research—involved 2,100 severely ill Covid- 19 patients. The researchers say their findings, which have yet to be peer-reviewed, suggest dexamethasone could save the life of 1 in 8 patients on a ventilator and 1 in 20 to 25 on oxygen. They emphasized, however, that the drug showed no benefits for those not on respiratory support and cannot prevent people from catching the virus.