30 June 2026

ONDINE BIOMEDICAL INC.
("Ondine Biomedical", "Ondine", or "the Company")

Published Leeds Study Shows Steriwave^® Reduced Surgical Site Infections by 78% versus standard of care using Mupirocin in High Risk Endoscopic Endonasal Skull-Base Surgery

·  Leeds researchers conclude in published study that Steriwave nasal photodisinfection be considered for routine adoption in high risk endoscopic endonasal skull-based surgeries, as data confirms significant reduction in surgical site infections (SSI) and meningitis risk over current standard of care using topical antibiotic mupirocin.

·  With a number needed to treat (NNT) of only 9, the cost to prevent one SSI is found to be only 12.3% of the average published cost to treat one SSI.

Ondine Biomedical Inc. (AIM: OBI), a leader in light-activated antimicrobial therapies for the prevention and treatment of hospital infections, announces that full results from Leeds Teaching Hospitals' evaluation of Steriwave^® nasal photodisinfection versus mupirocin in endoscopic anterior skull-base surgery have been published in The Journal of Laryngology & Otology. The Leeds researchers state that given its broad-spectrum rapid action, excellent compliance and lack of resistance potential, Steriwave represents a compelling alternative to mupirocin-based decolonisation and should be considered for routine adoption.

The Leeds researchers, Dr Paul Nix (Dept. of Otolaryngology) and Drs. Atul Tyagi, Nick Phillips and Asim Sheikh (Dept. of Neurosurgery) conclude that Steriwave significantly reduces SSI, antibiotic usage and ENT outpatient burden following endoscopic anterior skull base surgery. With a relative risk reduction of 78%, the number needed to treat would be 9 patients (95% CI: 5 to 27). The study finds an approximate cost of £774 per SSI prevented which compares (at only 12.3%) favourable to the published estimates of £6,300¹ average cost to treat a (non-meningitis) neurosurgery SSI and less than 2% of a meningitis related SSI.²

The publication entitled, 'Steriwave^® a Non-Antibiotic Nasal Photodisinfection Strategy Reduces Infection Burden in Endoscopic Skull Base Surgery', reports findings from a single-centre, before-and-after service evaluation conducted at Leeds General Infirmary, of the Leeds Teaching Hospitals NHS Trust. The evaluation compared outcomes between 105 patients (52.5%) managed with mupirocin (the standard 5-day pre-operative home-based topical antibiotic nasal decolonisation regimen) against 95 patients (47.5%) who received a single clinician-delivered Steriwave 5-minute nasal photodisinfection treatment immediately before EESB surgery.

Full study results demonstrated that Steriwave nasal photodisinfection was associated with a statistically significant reduction in 30-day surgical site infections ("SSIs") over mupirocin, with a relative risk reduction of 78% and an absolute risk reduction of 11.4% (95% CI 3.7%-19.1%, p=0.0059). The SSI rate was 3.2% in the Steriwave nasal photodisinfection arm compared with 14.6% in the standard-of-care arm using mupirocin topical nasal antibiotic. Compliance with Steriwave was 100%, compared with literature-reported compliance rates of about 39% for home-based mupirocin use.³ There were no adverse events related to Steriwave.

Most importantly, no cases of meningitis were recorded in the Steriwave arm (0%), compared with 5 cases (4.8%) in the standard of care arm. Endoscopic anterior skull base surgery is classed as clean contaminated, with meningitis risk heightened by dural opening and CSF leak. Postoperative meningitis is a severe, potentially life-threatening infection and inflammation of the meninges. Meningitis poses a significant risk to the patient and results in prolonged hospital stays. With severe meningitis cases potentially exceeding $60,000 (~£47,000)², the study generated a positive net Return on Investment (ROI), from the avoidance of these serious post-surgical infections alone.

The study authors noted that Steriwave's rapid action, clinician-delivered administration, high compliance profile and non-antibiotic mechanism represents a compelling alternative to mupirocin-based decolonisation. The interim study findings from the Leeds researchers were previously presented on 18 June 2026 at ENDOAthens, the 10th World Congress for Endoscopic Surgery of Sinuses, Skull Base, Brain, Spine & Orbit.

Carolyn Cross, CEO of Ondine Biomedical, said:

"We are deeply grateful to the Leeds General Infirmary clinical research team for their important work in this complex and high-risk surgical population. These superior nasal photodisinfection results over mupirocin point to a direct link between a broad spectrum of nasal pathogens-not only Staphylococcus aureus-and serious post-operative infections. This research underscores the clinical value of rapid, clinician-led, broad spectrum nasal decolonisation prior to endoscopic anterior skull-based surgeries. The Leeds team's pioneering work in this field, now published in a leading peer reviewed journal, has the potential to influence global practice and support improved quality of care for patients undergoing these high-risk procedures."

Endoscopic anterior skull-base surgery is a highly specialised procedure in which surgeons access structures at the skull base and brain through the nasal cavity. Because the nose is a recognised reservoir for pathogens, including antimicrobial-resistant organisms, reducing nasal microbial burden immediately before surgery is an important area of clinical interest in efforts to reduce infection risk in these complex procedures.

Steriwave is a five-minute, clinician-administered treatment designed to rapidly eliminate a broad spectrum of pathogens in the nasal vestibule using a light-activated antimicrobial process, without contributing to antimicrobial resistance. Because the treatment is delivered at the point of care immediately before surgery, it also helps address a practical challenge associated with multi-day, home-based decolonisation regimens: ensuring that the intended protocol has been completed before the patient enters the operating theatre.

References:

¹ Patel S, Thompson D, Innocent S, Narbad V, Selway R, Barkas K. Risk factors for surgical site infections in neurosurgery. Ann R Coll Surg Engl. 2019 Mar;101(3):220-225. doi: 10.1308/rcsann.2019.0001. Epub 2019 Jan 30. PMID: 30698457; PMCID: PMC6400918.

² Ivan ME, Safaee MM, Oh T, Joshi RS, Senders A, Blevins LS, et al. Predictive factors, 30-day clinical outcomes, and costs associated with cerebrospinal fluid leak in pituitary adenoma resection. J Neurol Surg B Skull Base. 2020 Feb;81(1):64-71. doi: 10.1055/s-0039-1677848.

³ Schweizer ML, Chiang HY, Septimus E, Moody J, Braun B, Hafner J, et al. Association of a bundled intervention with surgical site infections among patients undergoing cardiac, hip, or knee surgery. JAMA - Journal of the American Medical Association 2015;313:2162-2171

-- ENDS --

Enquiries:

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.