A drug normally prescribed to treat multiple sclerosis helped reduce the risk of severe disease from Covid-19, British researchers reported Thursday. But more research is needed to show whether the drug, which calms down the immune system, can really help people with severe coronavirus infections.
The researchers found British biotechnology company Synairgen's new experimental version of interferon beta-1a, repurposed to treat Covid-19, increased the odds of improvement and recovery among hospitalized Covid-19 patients in a Phase 2 trial.
"SNG001 reduced the odds of developing severe disease or dying by 79%," the researchers wrote in the journal The Lancet Respiratory Medicine.
SNG001 is an inhaled formula of interferon beta-1a, typically used to decrease inflammation and reduce the nerve damage caused by multiple sclerosis. In the trial, SNG001 was administered to 48 patients using a nebulizer while 50 patients received the placebo.
After two weeks, patients who got the daily treatment were twice as likely to get better by day 15 or 16 and more than three times as likely to improve by day 28 than those who got placebo, the researchers found. However, "there was no significant difference between treatment groups in the odds of hospital discharge or time to hospital discharge," the researchers wrote.
The researchers, from Synairgen and other institutions, found that during the two weeks of treatment, 21 patients -- or 44% -- in the SNG001 group recovered from disease compared with 11 patients -- or 22% -- in the placebo group. Then by the 28th day, 58% in the SNG001 group had recovered compared with 35% in the placebo group.
Overall, three patients died during the study and all were in the placebo group.
The researchers also found that 11 patients -- or 22% -- in the placebo group developed severe disease by day 16 compared with six patients -- or 13% -- in the SNG001 group.
The most common adverse event in the SNG001 group was headache.
"SNG001, a treatment already studied and shown to be well tolerated in patients with asthma and COPD, seems to also be well tolerated in patients admitted to hospital with COVID-19," the researchers wrote in the study. "These encouraging data provide a strong rationale for larger, international studies in the context of the ongoing clinical burden of COVID-19."
The study comes with limitations, including that the number of patients in the study was small.
'There would need to be a Phase 3 trial'
"There seems to be possibly a signal here, but it's unclear how much of a signal. There's not evidence that it's a dramatic signal, like a mortality signal necessarily, and it's a small study. I think the authors of the paper sum it up best when they say there would need to be a Phase 3 trial," said Dr. Jay Finigan, pulmonologist and director of The Respiratory Centers of Excellence at National Jewish Health in Denver, who was not involved in the new study.
"All in all, we're talking relatively small numbers and there is not a signal in terms of things like discharge or mortality, although it is certainly not powered for that," he said.
Currently, the drug remdesivir is the only treatment approved by the US Food and Drug Administration for Covid-19. Some other therapies -- Eli Lilly's antibody treatment and convalescent plasma -- have received emergency use authorizations for the treatment of Covid-19. Additionally, several experimental treatments are currently being studied.
"There are certainly lots of different drugs with different delivery mechanisms. There are other inhaled drugs that are being thought about and looked at and they target different areas," Finigan said.
"There are antiviral drugs, there are drugs acting on the immune system, antibodies, there are drugs that are trying to target inflammation and some of the inflammatory mediators," he said. "All in all, unfortunately the data that have come out in this population of patients have been pretty largely consistent in that none of them have shown a mortality benefit with the exception of dexamethasone," a corticosteroid.
When it comes to SNG001, "larger randomized clinical trials" are needed, Nathan Peiffer-Smadja and Yazdan Yazdanpanah, both of Bichat-Claude Bernard Hospital in Paris, wrote in an editorial that published alongside the new study in The Lancet Respiratory Medicine.
"The safety of nebulized interferon beta-1a will be of special interest since nebulization of interferon has no marketing authorization for any indication yet," Peiffer-Smadja and Yazdanpanah wrote.
"It will also be worthwhile to investigate whether interferon beta-1a has an impact on prolonged symptoms of COVID-19, especially pulmonary symptoms," they wrote. "To optimize the antiviral effect of interferon beta, there is a greater rationale to target patients at an early stage of the disease."