Feb. 5 (UPI) -- A single injection of an experimental antiviral drug appears to speed recovery times in non-hospitalized patients with COVID-19, according to a study published Friday by Lancet Respiratory Medicine.
In a phase 2 trial, testing whether the drug works for COVID-19 patients, those given peginterferon-lambda were four times as likely to have cleared the coronavirus infection within seven days. compared with those who received a placebo, the data showed.
The drug is being evaluated for the treatment of hepatitis D, a rare form of the liver disease, according to its manufacturer, Eiger Biopharmaceuticals, of Palo Alto, Calif.
"This treatment has large therapeutic potential," study co-author Dr. Jordan Feld said in a statement.
New treatments for COVID-19 are vital, "especially at this moment as we see aggressive variants of the virus spreading around the globe which are less sensitive to both vaccines and treatment with antibodies," said Feld, a liver specialist at Toronto Center for Liver Disease in Canada.
Peginterferon-lambda is synthetic form of a protein produced by the body in response to viral infections, and it has the ability to activate a number of cellular pathways to kill invading viruses.
COVID-19 prevents the body from producing interferons, which is one way it the coronavirus avoids being controlled by the body's immune system.
Treatment with interferon-lambda activates many of the same virus-killing cell pathways as the naturally occurring form, so it should be able to overcome drug resistance caused by new, emerging strains of the coronavirus, the researchers said.
Peginterferon-lambda also has fewer side effects than other forms of the drug because it is mostly active in the lungs, liver and intestines -- all places in which the COVID-19 virus tends to replicate -- but it is not active in other organs.
For this study, Feld and his colleagues treated 60 patients diagnosed with, but not hospitalized for, COVID-19, 30 of whom received a single dose of peginterferon-lambda, while 30 were given a placebo.
Seventy-nine percent of study participants with higher levels of the virus in their blood saw levels decrease after treatment, compared with 38% of those given the placebo, according to the researchers.
The apparent ability of peginterferon-lambda to clear the virus within a few days is key, as it could prevent people from progressing to more serious illness and reduces their risk of spreading the disease to others.
This could potentially shorten the time needed for self-isolation to avoid transmission, the researchers said.
"We also saw a trend towards quicker improvement of respiratory symptoms in the treatment group," Feld said.
"If we can decrease the virus level quickly, people are less likely to spread the infection to others and we may even be able to shorten the time required for self-isolation," he said.
Based on these results, a large Phase 3 trial, the final stage of the drug approval process, is planned for the near future, they said.