COVID-19 Antiviral Reduces Risk of Hospitalization, ER Visits by 50%

One dose of the investigational antiviral, peginterferon lambda (Eiger Pharmaceuticals), showed it reduced both hospitalization and emergency room visits for COVID-19 by half in a mostly previously vaccinated population (83%), according to a new phase 3 trial.

“The results conclusively show that this is an effective therapy to treat COVID-19 to reduce the risk of complications,” Jordan Feld, MD, MPH, one of the lead authors of the study, interim director of the Toronto Centre for Liver Disease and codirector of the Schwartz Reisman Liver Research Centre and the R. Phelan chair in Translational Liver Research at UHN, said in a statement.

The study was published in the New England Journal of Medicine.

Lambda is a late-stage, first-in-class, type 3 interferon (IFN) that stimulates immune responses that are critical for the development of host protection during viral infections and has been well-tolerated in clinical studies. The therapy is administered as a single subcutaneous injection so that it can be prescribed and administered at the first sign of infection or at first awareness of an exposure, potentially helping patients avoid severe illness that can lead to hospitalization and death, according to Eiger.

Trial Parameters and What the Data Says
The investigators conducted a randomized, controlled phase 3 trial titled the TOGETHER study involved predominantly vaccinated adults with COVID-19 infection in Brazil and Canada.

This was done in the outpatient setting, and participants presented with an acute clinical condition consistent with COVID-19 within 7 days after the onset of symptoms. All participants were either aged 50 or older, or had a health condition that put them at higher risk for severe COVID-19, such as diabetes, hypertension, obesity, being a transplant recipient, cancer patient, among other conditions. A total of 933 participants were assigned to receive pegylated interferon lambda—2 were subsequently excluded owing to protocol deviations—and 1018 were assigned to receive placebo. Participants received either pegylated interferon lambda (single subcutaneous injection, 180 μg) or placebo (single injection or oral).

The study’s primary outcome was hospitalization (or transfer to a tertiary hospital) or an emergency department visit (observation for >6 hours) due to COVID-19 within 28 days after randomization.

“A total of 25 of 931 patients (2.7%) in the interferon group had a primary-outcome event, as compared with 57 of 1018 (5.6%) in the placebo group, a difference of 51% (relative risk, 0.49; 95% Bayesian credible interval, 0.30 to 0.76; posterior probability of superiority to placebo, >99.9%),” the authors wrote. 

The effect of the treatment was even more pronounced in people who received the drug within three days of symptom onset, consistent with other antiviral medications for COVID-19. 

“The treatment effect increased (11 of 567 patients in the interferon group, as compared with 28 of 590 patients in the placebo group,” the authors reported of the patients in the 3 day cohort.

One of the potentially important aspects is the novel mechanism of action.
“An important feature of this treatment is that it is not affected by changes or mutations in the virus, because it works by stimulating the body’s own response to viral infection,” Feld said.