Large, ongoing studies of remdesivir are set to enter a new phase of research, in which doctors will test the impact of combining the drug with a medication already approved to treat multiple sclerosis, the National Institutes of Health announced Wednesday.
The multiple sclerosis drug, called interferon beta-1a, is sold under the brand name Rebif. It's been approved for use in the U.S. since 1996.
This latest phase of study builds on previous research that found the antiviral remdesivir can reduce the number of days COVID-19 patients are hospitalized, from 15 to 11, on average.
Just one other drug, a steroid called dexamethasone, has also been shown in clinical trials to benefit COVID-19 patients in a significant way. A British study found the steroid can reduce deaths by about a third in the sickest patients with the coronavirus.
Despite the promise of both remdesivir and dexamethasone, it's clear they will not be enough to control the pandemic that's now sickened more than 4.8 million people in the U.S., killing nearly 160,000.
What's more, remdesivir is given intravenously, which means patients usually must be in a medical facility to receive it. And it's costly. Gilead, remdesivir's manufacturer, announced in June that it will charge more than $2,000 per person for a typical treatment course of the drug. (Dexamethasone, while much cheaper, is only helpful in very sick patients, and could in fact be harmful when given in mild COVID-19 cases.)
A large clinical trial, sponsored by the National Institutes of Health, will now study the effects of combining remdesivir with interferon beta-1a.
An earlier study, posted to the preprint server medRxiv, suggested the interferon drug might help patients clear the virus more quickly.
Interferon is a molecule that's found naturally in the body, and it helps to fight a variety of viruses. COVID-19 patients tend to have a deficiency of the molecule, especially in their blood and lungs, Dr. Andre Kalil, a principal investigator for the trial at the University of Nebraska Medical Center in Omaha, said.
"If we replace the interferon in conjunction with an antiviral [remdesivir], maybe we can prevent the progression of the disease," Kalil said. "That's the hypothesis."
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About 1,000 patients hospitalized with COVID-19 worldwide will be included in the trial. Half will receive remdesivir plus shots of interferon beta-1a, four times every other day. The other half will get remdesivir plus placebo shots.
Interferon is known to come with side effects, such as flu-like symptoms, joint pain and fever, Kalil said, adding that most of those symptoms come after prolonged use of the drug.
Kalil's team is also wrapping up studies of remdesivir plus an anotther drug, an anti-inflammatory called baricitinib, used to treat rheumatoid arthritis.
Baricitinib, manufactured by Eli Lilly and marketed as Olumiant, is what's known as a Janus kinase (JAK) inhibitor. It blocks an enzyme that helps produce chemicals that lead to inflammation.
"It's a race to collect all the data, and make sure everything is correct," Kalil said. Those results aren't expected for about another month.
But, if the research finds that baricitinib offers a significant benefit for the sickest COVID-19 patients, the drug may be added to the trial with remdesivir and interferon beta-1a.
The plan is to continue zeroing in on a variety of treatments to find the best combination of medicines that would have the biggest impact on COVID-19.
Results on interferon beta-1a are expected sometime this fall.