Ena slices data to claim flu success in phase 2 and nasal spray's wide-ranging potential

Ena Respiratory had to fillet the data to claim a win from its phase 2a flu prophylaxis trial, insisting its nasal spray could ultimately be effective against viruses like COVID-19 and the common cold.

The Australian biotech was testing its broad-spectrum, innate immunomodulator INNA-051 against placebo in 123 adults who were then challenged with a substantial dose of H3N2 influenza A virus. However, interpreting the results was “complicated by lower than anticipated rates of infection in the placebo arm and an unexpectedly large proportion of participants having pre-existing immunity to the challenge strain across all groups,” according to a press release.

In a post hoc analysis that excluded participants with preexisting immunity to the flu strain in question, Ena argued that it was able to scrape a win, with a statistically significant shorter duration of infection among the remaining participants when compared to placebo. This effect was greater for those given the higher of the two doses, the biotech pointed out. There was also a dose-related drop in symptom duration, though the data were not statistically significant.

The study’s primary endpoint, however, was to evaluate the change in viral load at Day 8 after being subjected to the virus when compared to placebo, according to ClinicalTrials.gov.

The most common adverse events were "mild, short-lived and similar to those observed during the initial phase 1 study," the company added.

“This study further supports the concept that boosting the local innate immune response to common respiratory viruses has potential clinical benefit,” CEO Christophe Demaison, Ph.D., said in this morning's release. “We are eager to investigate INNA-051’s clinical benefit in the context of natural viral respiratory tract infections in individuals at increased risk of more severe illness.”

INNA-051 uses a TLR2/6 agonist to try to stimulate innate immune responses in airway epithelial cells. The aim is to help people fight off respiratory viral infections in the nasal passages where infections often first take hold, thereby reducing the risk of disease progression.

Ena’s ambition for INNA-051, which it argued is backed up by the latest trial results, is to use the spray to mitigate respiratory virus infections ranging from SARS-CoV-2 and flu to respiratory syncytial virus (RSV) and even the common cold in individuals at risk of more severe illness.

“Many people around the world have now been impacted by a ‘tripledemic’ of flu, RSV and SARS-Cov-2 viruses that have been circulating together in recent months,” Ena Chief Medical Officer Scott White, M.D., said in the release. “The surge in illness and hospitalization demonstrates the urgent need for a broad-spectrum treatment to boost immunity against common respiratory illnesses, and these data suggest INNA-051 is a promising option.”

The progress of INNA-051 caught the attention of Blue Knight, an initiative Johnson & Johnson set up with the U.S. government in response to the COVID-19 pandemic. Last May, Ena landed a spot on the initiative, positioning the biotech to benefit from mentorship as it seeks to hustle its infectious disease nasal spray to market.

Last month, the biotech received a further show of support in the form of a $4.4 million agreement with the U.S. Department of Defense to help fund development of INNA-051. Ena had previously raised $32 million Australian dollars ($24 million) in 2021 to fund the development of the nasal spray.

Besides the phase 2 flu trial, a midstage trial of INNA-05 in COVID-19 had at one point been planned to start last year, but Ena withdrew the study before any patients were enrolled.