ENA Respiratory Raises US$22.4m to Advance Once-Weekly Antiviral Nasal Spray
ENA Respiratory has closed a US$22.4 million (AU$34 million) Series B round to propel its lead therapy, INNA-051, into Phase 2 clinical development, marking a decisive step for the company’s community-based strategy to blunt common respiratory infections.
A Global Syndicate Backs an Australian Bet
The round brings heavyweight newcomers the Bill & Melinda Gates Foundation and Flu Lab onto the cap table, joining returning Australian investors Brandon Capital, Uniseed and Stoic Venture Capital.
The blend of international philanthropy and home-grown venture funding underscores a growing conviction that practical, easy-to-use prevention tools will be vital alongside vaccines and therapeutics during the heavy-hitting northern winter seasons.
INNA-051: Priming Defences Where Viruses Enter
At the heart of the raise is INNA-051, a once-weekly, dry-powder nasal spray formulated to prime the body’s natural antiviral defences in the nose – the front door through which viruses such as the common cold, influenza, RSV and coronaviruses typically enter.
By switching on these innate responses early and locally, ENA Respiratory aims to shorten the duration and reduce the severity of symptomatic infections and, critically, prevent disease progression to the lungs.
The company’s bet is elegant in its simplicity: fortify the gate, and you protect the fortress.
POSITS: A Community Trial Built for the Real World
The fresh capital fuels POSITS, an upcoming Phase 2 community study designed to test INNA-051 in the settings where respiratory viruses do their worst – homes, campuses and workplaces.
The trial will assess the safety, tolerability and efficacy of up to three months’ once-weekly dosing, enrolling up to 1,100 young adult participants in North America during the 2025–2026 respiratory virus season.
This pragmatic, real-world approach is intended to show how the product performs across typical circulation peaks, rather than under tightly controlled clinic-only conditions.
Led by a Seasoned Principal Investigator
POSITS will be led by Professor Justin Ortiz, Professor of Medicine at the University of Maryland’s Center for Vaccine Development and Global Health (CVDGH), as Principal Investigator.
With deep expertise in respiratory pathogens and vaccine evaluation, Ortiz brings the kind of operational and scientific leadership that can translate a promising mechanism into evidence that matters to regulators, clinicians and public-health planners.
Executive Confidence and Long-Term Backing
ENA Respiratory’s CEO framed the Series B as a major milestone that puts the company in a strong position to evaluate the impact of a once-weekly powder nasal spray that stimulates natural antiviral defences in a community setting – moving the programme closer to patients who need it most.
That sentiment is echoed by the company’s Non-Executive Director and Brandon Capital partner, who noted Brandon’s support since the earliest days, driven by the potential for INNA-051 to transform the prevention and management of respiratory infections.
Why This Matters Now
Respiratory viruses remain a stubborn, seasonal drain on health systems and productivity. While vaccines and antivirals have reshaped parts of the landscape, there is still a glaring need for broad-spectrum, user-friendly tools that can be deployed early, widely and regularly.
If INNA-051 can demonstrate that once-weekly self-administration reliably blunts symptoms and reduces escalation to the lower respiratory tract, it could slot into a preventive toolkit alongside vaccination – especially for communities prone to recurrent exposure.
The Road Ahead
With funding secured and a seasoned study team in place, ENA Respiratory now turns to the operational choreography of a large-scale community trial: site activation, participant engagement and capturing high-quality outcomes data across an entire virus season.
The company’s investor mix suggests alignment around both the scientific promise and the public-health utility of an INNA-051-style intervention, should the evidence stack up.
Conclusion
ENA Respiratory’s US$22.4m (AU$34m) Series B signals strong confidence in INNA-051, a once-weekly, dry-powder nasal spray that aims to prime innate antiviral defences where respiratory viruses first take hold.
With POSITS set to enrol up to 1,100 young adults in North America through the 2025–2026 season, the company is positioned to generate the kind of real-world data that can shift practice.
Backed by a coalition including the Gates Foundation, Flu Lab, Brandon Capital, Uniseed and Stoic Venture Capital, ENA Respiratory is advancing a practical, prevention-first approach – one that, if successful, could reshape how communities prepare for and weather the annual wave of respiratory infections.
News Credits; ENA Respiratory secures US$22.4m to advance nasal spray therapy
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