A large federal trial of remdesivir has entered its next phase, in which researchers will test the effects of combining the antiviral drug with a pill to bring down inflammation.
The pill, called baricitinib, was approved in 2018 to treat rheumatoid arthritis.
Remdesivir, manufactured by Gilead Sciences, is the only treatment that's been shown in a clinical trial to have an effect on COVID-19 so far. Preliminary results from that trial, which included sites worldwide, published Friday in The New England Journal of Medicine, found that the drug reduced patients' length of hospital stay by about four days, from 15 days, on average, to 11 days. More than 1,000 patients hospitalized with COVID-19 received either remdesivir or a placebo.
The ongoing trial, which is sponsored by the National Institute of Allergy and Infectious Diseases, did not show the drug had a significant impact on deaths. However, researchers said the shortened hospital stays was an important finding.
"Four days being sick in a hospital receiving major care, being intubated, receiving oxygen, is an eternity," Dr. Andre Kalil, a principal investigator for the trial at the University of Nebraska Medical Center in Omaha, said.
"The longer you stay in the hospital, the higher the chances of forming blood clots," Kalil told NBC News. "The longer you stay in a hospital, the higher the chance of getting hospital-acquired infections."
Still, it's clear remdesivir on its own will not be enough to make a considerable impact on cases of COVID-19. For the next phase of the trial, all patients will receive remdesivir. Half will also get baricitinib, and the other half will get a placebo. Researchers anticipate 600 to 700 patients will be recruited.
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Baricitinib, like hydroxychloroquine, is prescribed for patients with rheumatoid arthritis. (Though early studies hinted that hydroxychloroquine might be beneficial in treating the coronavirus, more recent research has not.)
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. In COVID-19 patients, it's the body's extreme inflammatory response that's thought to be most damaging, more so than the virus itself.
"If we can minimize the inflammation, and minimize the viral replication at the same time, we could further increase the clinical benefits of the patient," Kalil said.
Like all drugs, baricitinib can have side effects. The drug dampens the immune system, and researchers will be watching to make sure infections don't, in fact, worsen. It's also known to increase platelet count.
"We need to monitor for that too, because if it gets too high, the patients could have an increased risk for developing a blood clot," Dr. Aneesh Mehta, an associate professor of medicine at the Emory University School of Medicine, said. Mehta is also a lead investigator in the NIH's remdesivir trial.
An increase in blood clots has already been widely reported among COVID-19 patients. "That's one of the unique challenges of taking care of patients with COVID-19," Mehta said.
"Many of us have adjusted our treatment protocols" to include blood thinners to counter that risk, he said.
Researchers anticipate the next set of preliminary results from the ongoing trial will be available in the summer. The plan is to continue honing a variety of treatments to find the best combination of medicines that would have the biggest impact.
"We will just not stop," Kalil said. "We'll keep trying different treatments that are going to have the potential to improve patients."