18 June 2026

ONDINE BIOMEDICAL INC.

("Ondine Biomedical", "Ondine", or "the Company")

Nasal Photodisinfection Reduces Surgical Infections in Complex Brain Surgery by 78.5% Compared to Nasal Antibiotics at Leeds Teaching Hospitals

Interim study results being presented today at ENDOAthens, the 10^th World Congress for Endoscopic Surgery of Sinuses, Skull Base, Brain, Spine & Orbit

Full study results accepted for publication in The Journal of Laryngology & Otology

Ondine Biomedical Inc. (AIM: OBI), a leader in light-activated antimicrobial therapies to prevent and treat hospital infections, announces that interim results from a study at Leeds Teaching Hospitals using Ondine's nasal photodisinfection technology, Steriwave^®, before complex brain surgery performed through the nose led to a 78.5% reduction in surgical site infections ("SSIs") compared to standard 5-day antibiotic nasal treatment. There were recorded no cases of meningitis.

The initiative, led by Leeds Teaching Hospitals' Dr. Paul Nix, Consultant ENT Surgeon, is being presented today at ENDOAthens, the 10th World Congress for Endoscopic Surgery of Sinuses, Skull Base, Brain, Spine & Orbit, taking place in Athens, Greece, 15-18 June, 2026.

The study's interim analysis involving 189 patients at Leeds Teaching Hospitals demonstrated a 78.5% reduction in SSIs (p=0.0052) with no recorded cases of meningitis amongst patients who received the painless 5-minute pre-surgical nasal photodisinfection protocol using Steriwave before complex brain surgery.

The nose is a reservoir for harmful pathogens, which are among the main causes of SSIs. In this first-of-its-kind study involving endoscopic endonasal skull-base surgery ("EESB"), the Leeds clinical team assessed whether delivering nasal photodisinfection in hospital immediately before surgery could improve outcomes for this high-risk patient population.

Traditional nasal decolonisation requires patients to apply antiseptic or antibiotic treatments at home for five days before surgery, but only around 40% complete the treatment as directed. By moving the process into the clinical setting, the new approach achieved 100% compliance.

A manuscript reporting the full 200-patient dataset has been accepted for publication in The Journal of Laryngology & Otology. The final manuscript title and full study results will be made available upon publication.

The project was supported, in part, by funding from Leeds Hospitals Charity as part of its commitment to innovation in hospitals and improving patient outcomes through charitable funding.

Dr. Paul Nix, Consultant ENT at Leeds Teaching Hospitals NHS Trust, commented:

"By significantly reducing the risk of patients not completing home-based decolonisation treatments and reducing harmful bacteria in the nose before surgery, we can better protect patients from infection and improve outcomes. Presenting these findings at ENDOAthens gives us the opportunity to share an important advance in neurosurgical safety and infection prevention with colleagues around the world."

Elevating Safety at the Premier Global Skull Base Forum

ENDOAthens is the world's premier multidisciplinary event for endoscopic skull base sciences. Organized in conjunction with the European Skull Base Society (ESBS), the congress devotes itself to the free interchange of international knowledge, teaching, and therapy of skull base diseases. Its core mission is to evaluate and systematize current advances made by individual skull base disciplines to directly benefit patients.

EESB allows surgeons to access tumours, pituitary glands, and the brain through the nasal cavity without traditional craniotomies and requires an extraordinary level of precision. Unlike standard spinal or superficial surgical site infections, EESB creates a direct pathway between the bacteria-rich nasal cavity and the brain's subarachnoid space. If that barrier is breached, bacteria can enter the cerebrospinal fluid and quickly cause septic thrombosis, stroke, severe neurological injury, and prolonged stay in intensive care.

The nasal surgical corridor leaves the central nervous system uniquely vulnerable to a patient's own nasal bacteria, historically resulting in standard UK post-operative meningitis rates between 1.8% and 2.6%. Neurosurgical literature typically reports mortality rates of 10% to 30% for post-operative meningitis, suggesting pre-incisional prevention as a critical focus to eliminate this mortality risk.

Carolyn Cross, CEO of Ondine Biomedical, added:

"We are incredibly proud that Dr. Nix's pioneering work has been recognised by the European Skull Base Society and the ENDOAthens committee. This is the first nasal photodisinfection study in EESB and we are thrilled with the initial outcomes using our non-antibiotic technology. Accessing brain surgery through the nose is a remarkable medical advancement, but it inherently elevates the risk of patient self-infection as many pathogens reside in the nose. Applying broad-spectrum photodisinfection shortly before skull base surgery is a logical and important step to help protect patients against deep-tissue infections that carry a heavy morbidity and mortality burden."

Dr. Nix's presentation at ENDOAthens will showcase how standardising clinician-led approaches aligns with national GIRFT ("Get it Right First Time") safety targets, supports antimicrobial stewardship, and helps protect vulnerable patients from life-threatening complications.

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About Leeds Teaching Hospitals NHS Trust

Leeds Teaching Hospitals NHS Trust is one of the largest and busiest acute hospital trusts in the UK, providing local and specialist services across Leeds, the Yorkshire and Humber region and beyond. The Trust delivers care from seven hospitals across five sites, including Leeds General Infirmary, and is a major centre for specialist care, research, innovation and medical education.

About Ondine Biomedical Inc.

Ondine Biomedical Inc. is a Canadian life sciences company focused on the development of light-activated antimicrobial therapies ('photodisinfection') for the prevention and treatment of infections, including those associated with multidrug-resistant organisms.

Ondine's lead product, Steriwave^®, is authorized for nasal decolonisation in Canada and certain international markets. In the United States, the technology has been granted Qualified Infectious Disease Product designation and Fast Track status by the U.S. Food and Drug Administration and recently completed enrolment in its Phase 3 clinical trial.

The Company has a pipeline of additional photodisinfection products in various stages of development for application in areas including chronic sinusitis, ventilator-associated pneumonia, burns and other indications.

U.S. Regulatory Status and Clinical Data Disclaimer

Ondine's light-activated antimicrobial technology, commercially available as Steriwave^® in certain jurisdictions, is not approved, cleared, or commercially available for sale or clinical use in the United States and is limited by U.S. law to investigational use only.

References to clinical outcomes in this release should be interpreted in the context of the specific studies or real-world evaluations described and do not imply regulatory approval for any particular indication.