The company announced results Monday from a small clinical trial of its drug known as SNG001 that it called a potential “major breakthrough” in the fight against the bug, even though the study reportedly has not been peer-reviewed or published in full.

Those who received the nebulizer treatment in Synairgen’s trial of 101 COVID-19 patients from nine UK hospitals were 79 percent less likely than those who got a placebo to become so sick that they’d need a ventilator, and at least twice as likely to recover without limitations to their everyday activities, the company said.

They also experienced less “breathlessness” — a main COVID-19 symptom — during the 16-day treatment period and were discharged from hospitals after a median of six days, compared with nine days for the placebo group, according to the results.

“The results confirm our belief that interferon beta … has huge potential as an inhaled drug to be able to restore the lung’s immune response, enhancing protection, accelerating recovery and countering the impact of SARS-CoV-2 virus,” Tom Wilkinson, a University of Southampton professor who was the trial’s chief investigator, said in a statement.

Synairgen is now focused on working with regulators and others to “progress this potential COVID-19 treatment as rapidly as possible,” CEO Richard Marsden said. The US Food and Drug Administration has already approved another coronavirus treatment called remdesivir, Gilead Sciences’ antiviral drug that’s been shown to help coronavirus patients recover faster.

Synairgen’s announcement sent its stock price up more than 400 percent to 192 British pence, or $2.43 a share, as of 10:12 a.m. But medical experts reportedly cautioned that it’s hard to draw conclusions from a small study that has yet to go through a rigorous peer review.

“It would be good to see the full results once presented and peer-reviewed to make sure they are robust and the trial conduct was rigorous,” Naveed Sattar, a professor of metabolic medicine at the University of Glasgow, told the BBC. “Also, with small numbers comes less certainty on the true level of benefit, or whether benefits vary between people with differing risk characteristics.”

Synairgen’s drug is a form of the interferon beta protein — which the body produces to fight infections — that patients inhale through a nebulizer. An injected form of the protein is already used to treat multiple sclerosis.