ENA Respiratory Successfully Completes First Part of Phase II Study of INNA-051 Nasal Spray Designed to Protect Against Symptomatic Viral Respiratory Infections

Melbourne, Australia, 11 May 2026 – ENA Respiratory, a clinical-stage pharmaceutical company developing antiviral host defence enhancers to minimize the impact of symptomatic viral respiratory infections, today announces the successful completion of Part A of its Phase IIa community study of INNA-051, and progression to Part B.

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) is evaluating the safety, tolerability and efficacy of up to three months’ treatment with INNA-051 and assessing 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.

In Part A, the study recruited 200 participants across five sites in the USA, including the Center for Vaccine Development and Global Health (CVD) at the University of Maryland, Baltimore, the Naval Medical Research Command (NMRC) Clinical Trials Center, Bethesda, Maryland and three Accellacare clinical sites in North Carolina. Four weeks of dosing have now been completed with no safety concerns identified.

The Safety Review Committee has endorsed progression to Part B following a safety review of Part A. Part B will recruit 900 participants during the next North American respiratory virus season, with participants dosed for three months. Recruitment will continue to 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 (https://enarespiratory.com/inna-051/clinical-trials/).

ENA Respiratory’s Medicine Development Leader, Ruth Tal-Singer, PhD said: “The successful completion of the first part of this Phase IIa study and the Safety Review Committee’s endorsement to progress to larger scale and longer dosing represent important milestones in the development of INNA-051. We look forward to continuing this productive collaboration with our excellent clinical partners as we advance this program to bring this important new therapy option closer to reaching those in need.”