COVID drug shows promise in new study — but will patients ever get access?

This is an excerpt from Second Opinion, an analysis of health and medical science news emailed to subscribers weekly. If you haven't subscribed, you can do that by clicking here.

A drug aimed at curbing severe COVID-19 is stirring excitement among scientists, given the limited treatments left to beat back serious infections — but some doubt it will ever reach patients.

Canadian research on the drug, called pegylated interferon lambda, is just the latest chapter in a years-long saga to find effective COVID treatments, one that's been filled with promising prospects, regulatory roadblocks, and ultimately a series of dead-ends as many drugs proved powerless against this ever-evolving virus. 

Monoclonal antibodies, once considered life-saving, no longer work against new variants — leaving Pfizer's antiviral, multi-pill drug Paxlovid as one of the last tools in the toolbox.

Researchers' renewed hope centres on a different type of drug based on a specific type of interferon — a substance typically made by the body's own cells to help the immune system fight infections — which appears to hold up against various variants of SARS-CoV-2.

A study from researchers at McMaster University in Hamilton and the University Health Network (UHN) in Toronto, published this week in the New England Journal of Medicine, found the drug reduced the risk of hospitalization.

The randomized clinical trial involved close to 2,000 participants, mostly from Brazil and some from Toronto, and took place between June and March 2021.

The bulk of subjects, around 84 per cent, were previously vaccinated against COVID-19. 

"What we saw is that a single dose of the treatment reduced the probability of people who are at high risk for severe COVID ending up requiring hospitalization with their illness by about 50 per cent in people who were vaccinated," said UHN researcher Dr. Jordan Feld. 

"And in people who were not vaccinated, the effect was greater — almost 90 per cent reduction."

Dr. Donald Vinh, an infectious diseases specialist with McGill University, called the drug's potential "amazing" during an e-mail exchange with CBC News, "because it shows that we can harness the power of the immune system, and augment it to provide protection against infection, and to do it with relatively few side effects."

The drug would also be straightforward to administer, as it's just one single injection into the skin, much like an insulin shot — something patients could even do themselves, if necessary.

What's far less clear is whether any patients will actually get the drug in the first place.

The specific type of interferon studied by the Canadian research team uses a receptor that's only found in certain parts of the body, primarily the lungs and liver, Feld said. (His interest in the drug stems from his primary work as a liver disease researcher.)