COVID-19: Peginterferon Lambda May Prevent Clinical Deterioration, Shorten Viral Shedding

Walter Alexander

February 10, 2021

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In outpatients with COVID-19, peginterferon lambda has the potential to prevent clinical deterioration and shorten the duration of viral shedding, according to results of a double-blind, placebo-controlled trial (NCT04354259).

Reductions in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA were greater with peginterferon lambda than with placebo from day 3 onward in the phase 2 study led by Jordan J. Feld, MD, of the Toronto Centre for Liver Disease. The findings were reported in The Lancet Respiratory Medicine.

Fewer Side Effects

To date in randomized clinical trials, efficacy in treatment of COVID-19 has been shown only for remdesivir and dexamethasone in hospitalized patients, and in an interim analysis of accelerated viral clearance for a monoclonal antibody infusion in outpatients.

Activity against respiratory pathogens has been demonstrated for interferon lambda-1, a type III interferon shown to be involved in innate antiviral responses. Interferons, Feld and coauthors stated, drive induction of genes with antiviral, antiproliferative and immunoregulatory properties, and early treatment with interferons might halt clinical progression and shorten the duration of viral shedding with reduced onward transmission. In addition, interferon lambdas (type III) use a distinct receptor complex with high expression levels limited to epithelial cells in the lung, liver, and intestine, leading to fewer side effects than other interferons, including avoiding risk of promoting cytokine storm syndrome.

The researchers investigated peginterferon lambda safety and efficacy in treatment of patients with laboratory-confirmed, mild to moderate COVID-19. Sixty patients (median age 46 years, about 60% female, about 50% White) were recruited from outpatient testing centers at six institutions in Toronto, and referred to a single ambulatory site. Patients were randomly assigned 1:1 to a single subcutaneous injection of peginterferon lambda 180 mcg or placebo within 7 days of symptom onset or, if asymptomatic, of their first positive swab. Mean time from symptom onset to injection was about 4.5 days, and about 18.5% were asymptomatic. The primary outcome was the proportion of patients negative for SARS-CoV-2 RNA on day 7 after the injection.

Greater Benefit With Higher Baseline Load

A higher baseline SARS-CoV-2 RNA concentration found in the peginterferon lambda group was found to be significantly associated with day 7 clearance (odds ratio [OR] 0.69 [95% confidence interval 0.51-0.87]; P = .001). In the peginterferon lambda group, also, the mean decline in SARS-CoV-2 RNA was significantly larger than in the placebo group across all time points (days 3, 5, 7, and 14). While viral load decline was 0.81 log greater in the treatment group (P = .14) by day 3, viral load decline increased to 1.67 log copies per mL by day 5 (P = .013) and 2.42 log copies per mL by day 7 (P = .0041). At day 14, the viral decline was 1.77 log copies per mL larger in the peginterferon lambda group (P = .048).

The investigators pointed out that the difference in viral load decline between groups was greater in patients with high baseline viral load (at or above 106 copies per mL). In the peginterferon lambda high baseline viral load group, the reduction was 7.17 log copies per mL, versus 4.92 log copies per mL in the placebo group (P = .004).

More Patients SARS-CoV-2 RNA Negative

By day 7, 80% of patients in the peginterferon lambda group were negative for SARS-CoV-2 RNA, compared with 63% in the placebo group (P = .15). After baseline load adjustment, however, the peginterferon lambda treatment was significantly associated with day 7 clearance (OR 4.12 [95% CI 1.15-16.73]; P = .029).

Respiratory Symptoms Improved Faster

Most symptoms in both groups were mild to moderate, without difference in frequency or severity. While symptom improvement was generally similar over time for both groups, respiratory symptoms improved faster with peginterferon lambda, with the effect more pronounced in the high baseline viral load group (OR 5.88 (0.81-42.46; P = .079).

Laboratory adverse events, similar for both groups, were mild.

"Peginterferon lambda has potential to prevent clinical deterioration and shorten duration of viral shedding," the investigators concluded.

"This clinical trial is important" because it suggests that a single intravenous dose of peginterferon lambda administered to outpatients with a positive SARS-CoV-2 nasopharyngeal swab speeds reduction of SARS-CoV-2 viral load, David L. Bowton, MD, FCCP, professor emeritus, Wake Forest Baptist Health, Winston-Salem, N.C., said in an interview. He observed that the smaller viral load difference observed at day 14 likely reflects host immune responses.

Bowton also noted that two placebo group baseline characteristics (five placebo group patients with anti-SARS-CoV-2 S protein IgG antibodies; two times more undetectable SARS-CoV-2 RNA at baseline assessment) would tend to reduce differences between the peginterferon lambda and placebo groups. He added that the study findings were concordant with another phase 2 trial of hospitalized COVID-19 patients receiving inhaled interferon beta-1a.

"Thus, interferons may find a place in the treatment of COVID-19 and perhaps other severe viral illnesses," Bowton said.

The study was funded by the Toronto COVID-19 Action Initiative, University of Toronto, and the Ontario First COVID-19 Rapid Research Fund, Toronto General & Western Hospital Foundation.

Bowton had no disclosures. Disclosures for Feld and coauthors are listed on the Lancet Respiratory Medicine website.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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