ENA Respiratory Announces Dosing of First Participants in Phase II Study of INNA-051 Nasal Spray Designed to Protect Against Symptomatic Viral Respiratory Infections

Melbourne, Australia, 29 January 2026 – ENA Respiratory, a clinical-stage pharmaceutical company developing antiviral host defence enhancers to minimize the impact of symptomatic viral respiratory infections, today announces it has dosed the first participants in its Phase II community study of INNA-051, [with the first participant dosing now completed].

INNA-051 is a virus-agnostic, once-weekly, dry powder nasal spray which primes the natural antiviral host defences in the nose where viruses like colds, flu, RSV and coronaviruses typically enter, enabling the body to respond more quickly when challenged. INNA-051 therapy aims to reduce the incidence of complications in patients at higher risk of severe illness.

The ‘POSITS’ study (https://clinicaltrials.gov/study/NCT07222670) will evaluate the safety, tolerability and efficacy of up to three months’ treatment with INNA-051 and assess its impact on the incidence, duration and severity of symptomatic infections caused by common respiratory viruses, including influenza, RSV, rhinovirus, and coronaviruses in young adult participants at risk of illness due to living or working in crowded environments.

The study will recruit up to 1,100 generally healthy male and female participants who are at increased risk for exposure to viral respiratory infections. An initial 200-participant safety Phase A is being conducted during the current North American respiratory virus season, with weekly dosing for four weeks. This will be followed next season by a 900-participant Phase B with participants being dosed for three months.

Recruitment will target those in severely crowded households, residents of university housing, military personnel living in barracks, childcare center workers and/or those living with or caring for a child aged 10 or less attending school or day care. The first participants were dosed at the Center for Vaccine Development and Global Health (CVD) at the University of Maryland, Baltimore with additional participants being recruited at the Naval Medical Research Command (NMRC) Clinical Trials Center, Bethesda, Maryland.

Viral respiratory infections are a major global health problem, and the impact is most significant for patients with underlying medical conditions such as asthma, COPD, heart disease, kidney disease, diabetes, primary immunodeficiency and cancer, who face a much higher risk of complications.

ENA Respiratory’s CEO, Christophe Demaison, PhD said: “The start of the POSITS study is an important next step for ENA Respiratory and for the development of INNA-051. Our previous pre-clinical and clinical work has shown INNA-051 to have the potential to shorten the duration of symptomatic infections, prevent progression to the lungs, and reduce complications.

“There were over a million hospitalizations and up to 200,000 deaths in the U.S. in 2025 from respiratory-related viral infections in such patients last year. By boosting the body’s natural host defense pathways INNA-051 could offer a new option for millions of vulnerable patients worldwide and this study is an opportunity to add significantly to our evidence of its potential.”