“Inhaled interferon beta-1a has demonstrated antiviral activity against a range of respiratory viruses, including SARS-CoV-2,” outlined Prof. Tom Wilkinson (University of Southampton, UK)1. Moreover, inhaled delivery optimises the exposure of this agent to the tissue it should target, without ample systemic exposure2,3. Positive phase 2 results of this agent in COVID-19 led to the unfoldment of the phase 3 SPRINTER trial (NCT04732949)4. The trial randomised 623 patients who were hospitalised with moderate COVID-19 1:1 to a 14-day course of inhaled interferon beta-1a plus standard care or placebo plus standard care. The primary endpoints were the time to hospital discharge and the time to recovery to ‘no limitations of activities’ up to day 28.
No difference was observerd in time to hospital discharge between the 2 arms of the study (HR 1.06; 95% CI 0.89‒1.27; P=0.509). Key secondary endpoints did not demonstrate a benefit of inhaled interferon beta-1a over placebo either but trended towards a benefit for the intervention arm: progression to severe disease or death (placebo 14.4% vs interferon beta-1a 10.7%; OR 0.71; P=0.161). Furthermore, in patients with O2 saturation ≤92% or respiratory rates ≥21 breaths per minute, the per-protocol analysis did show a trend towards a reduced risk of severe disease or death in those who were treated with inhaled interferon beta-1a instead of placebo (3.4% vs 12%; P=0.046).
The safety profile of inhaled interferon beta-1a was favourable and consistent with previously reported data. The rates of serious treatment-emergent adverse events were 12.6% and 18.2% in the experimental arm and placebo arm, respectively.
Prof. Wilkinson concluded that the favourable trends for inhaled interferon beta-1a over placebo that were observed in the current trial provide a clinical rationale to investigate the effect of this agent on the endpoint of progression of disease or mortality in hospitalised patients with COVID-19 and in patients with severe viral lung infections.