
Daily use of an interferon-alpha (IFN-α) nasal spray lowers the risk of COVID-19 infection in adults with cancer, a new randomized controlled trial finds.
For the multicenter study, published last week in Clinical Infectious Diseases, researchers at the University of Melbourne in Australia randomly assigned participants to receive daily IFN-α nasal spray (217 participants) or a saline placebo (216) from December 2020 to April 2023. Participants had solid-tumor or blood cancer with no history of COVID-19 infection.
Participants who developed influenza-like symptoms in the 90 days after randomization collected nasal swabs for polymerase chain reaction (PCR) testing for COVID-19, influenza A/B, respiratory syncytial virus, parainfluenza, adenovirus, seasonal coronavirus, picornavirus, and/or human metapneumovirus, or they had COVID-19 rapid antigen testing.
Study visits occurred at 30, 60, and 90 days, at which time participants provided blood samples and completed a questionnaire.
"Preventative measures, such as vaccination and monoclonal antibodies, have dramatically improved outcomes but many cancer populations experience breakthrough infections and have suboptimal vaccine responses," the authors wrote.
Lower rates in younger, female, vaccinated patients
The COVID-19 infection rate was lower in the IFN-α group than in placebo recipients (8.3% vs 14.4%), for a 40% reduced risk. The incidence of other viral respiratory infections was 5.1% in both groups, but the case numbers were too low to reach a conclusion about efficacy.
There may be a role for short-term IFN-α nasal spray in addition to vaccination and monoclonal antibodies in preventing COVID-19.
In the 389-person per-protocol cohort, rates of COVID-19 infection in IFN-α and placebo recipients were 7.7% and 16.0%, indicating half the risk. Other respiratory virus incidence was 4.6% and 5.7% in the two groups, respectively.
A subgroup analysis demonstrated lower COVID-19 incidence in IFN-α recipients younger than 65 years (relative risk [RR], 0.48), women (RR, .44), and vaccinated recipients (RR, 0.50) but no difference by cancer type, disease severity, hospitalization, or death. IFN-α was well tolerated.
The researchers noted that IFN-α has antiviral, antimicrobial, antiproliferative, and immunomodulatory effects. "There may be a role for short-term IFN-α nasal spray in addition to vaccination and monoclonal antibodies in preventing COVID-19," they wrote.