New one-and-done therapy can help curb severe COVID-19 infection: Canadian-led study

Just one injection of an antiviral drug, given early in a COVID-19 infection, offers significant protection in keeping people, even those at high risk, out of the hospital and alive, a new study says.

The drug, peg-interferon lambda, was tested in nearly 2,000 people—both those vaccinated and unvaccinated—with COVID-19 in Canada and Brazil.

Researchers found that when vaccinated patients received a single dose by injection, they were 51 per cent less likely to end up in hospital or die when compared to people given a placebo. Among patients who weren't vaccinated, the effect was even greater, with 89 per cent fewer hospitalizations and deaths.

The study was published in the peer-reviewed New England Journal of Medicine's website on Wednesday.

"The way that this therapy works is it's stimulating the body's own immune system to clear the virus," said Dr. Jordan Feld, study co-author and a senior scientist at the Toronto General Hospital Research Institute at University Health Network.

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The effect of the treatment, according to the study, was even more striking in people who got the drug within three days of the start of their symptoms. The experimental therapy was also effective across several different variants, including Omicron.

Interferon is normally produced by the body in response to a viral infection. Interferon lambda specifically targets tissue in the lungs.

"In a sense, we're giving back something that the body is not producing because the virus that causes COVID-19 is dampening the production of interferon," Feld said in an interview with CTV News.

The study was conducted on people who were considered at higher risk of severe COVID because they were over the age of 50 or had health conditions like diabetes, high blood pressure, obesity, cancer, or immune disorders.

Where other COVID-19 treatments for early infection like Paxlovid require multiple pills over several days, this therapy potentially offers similar protection with one treatment.

"You ... test positive, you get the injection and you're done because it's a single dose," said Feld, who is also a professor of medicine at the University of Toronto.

The medication, he says, stays in the body for about a week.

"For people [who] have trouble with adherence to medicines, with drug interactions with the other medicines they're taking, this would be an easier therapy to administer," he added.

The injections were only 180 micrograms, a tiny dose, delivered to the stomach for the study, though researchers say it could be delivered by self-injection like insulin.

Study participants reported few or no side-effects.

Maury Shnier, who has Crohn's disease, was one of the participants and was recently told he received the injection, not the placebo.

"I've had flu [cases] that were probably worse than my experience [with COVID-19]. I was sick for maybe a week or two. There was one or two days where I just didn't feel like working, but the rest of the time I was able to participate and get on with life," Shnier told CTV News.

While he can’t tell if the injection changed the course of his illness, the Toronto man says he's happy to have helped scientists learn more about this potential treatment, especially for patients who, like him, have immune disorders that boost their risk of severe illness.

"I am gratified to have been part of the trial," he said.

But there are questions about the logistics of administering this drug by injection.

"Who will give it, and where to get it," said Dr. Neil Rau, an infectious disease doctor who was not part of the study.

While intrigued by the results, he told CTV News, "the devil will be in the details, the cost, and do the positive results hold out over time with a bigger number of people?"

The study drug is produced by an American company, Eiger Biopharmaceuticals, and is not yet approved for sale in Canada or the U.S., and so researchers tell CTV News there is no projected cost at the moment.

But studies are already in the works to see about its possible use in other respiratory conditions like RSV and the flu.

"This is not a viral-specific intervention," said Dr. Edward Mills, a professor in the Department of Health Research at McMaster University, who was also part of the study, along with McMaster scientist Dr. Gilmar Reis, the lead author.

"We're now going to try it out for influenza. And we think that this is very exciting because no one knows what the next respiratory pandemic is going to be, but this could be a front-line treatment," Mills told CTV News.