Scholars propose efficient treatment for uncommon vision-threatening infection, ET HealthWorld


London : In a groundbreaking global clinical study, a medication candidate based on innovative UCL and Moorfields Eye Hospital research and currently under development by SIFI S.p.A. was discovered to be highly successful in curing an unusual eye infection that poses a threat to vision.

The findings, published in the Ophthalmology journal, reveal the effectiveness and safety of the first pharmacological candidate for treating Acanthamoeba keratitis (AK) using a unique and evidence-based treatment strategy.

AK is a form of microbial keratitis (corneal infection) – a condition that causes inflammation of the cornea (the clear protective outer layer of the eye). AK can lead to severe pain and sensitivity to light.

AK is relatively rare, affecting approximately one in 37,000 contact lens wearers per year in the UK, but it accounts for approximately half of all cases of vision loss in this group. Contact lens wearers face a higher risk of developing the disease; a recent study by UCL and Moorfields Eye Hospital found that individuals who wear reusable contact lenses face nearly four times the risk compared to those wearing daily disposables, and showering or wearing lenses overnight also raises the risk by more than threefold.*

The treatment under investigation, low concentration polihexanide (PHMB 0.02 percent), was initially developed and used in the 1990s for treating AK, introduced by a team co-led by Professor John Dart, the lead author of this latest study, and is widely recommended as a therapy for AK. However, it is not an approved drug, and treatment outcomes have been inconsistent.

Professor John Dart (UCL Institute of Ophthalmology and Moorfields Eye Hospital NHS Foundation Trust) stated: “Acanthamoeba keratitis in contact lens users can be prevented by following safe use advice: if possible, use daily disposables, wash and dry hands before handling lenses, maintain good lens and lens case hygiene, and avoid wearing them while bathing, swimming, or showering. If you do wear them overnight, use goggles and replace the lenses after use.”

“Unfortunately, when the disease does develop, it tends to have a long duration and, in recent times, one-third of patients have experienced poor visual outcomes, with one-fourth requiring surgery at some point.”

“PHMB 0.02 percent is an effective and widely recommended unapproved therapy, but many clinicians struggle to obtain it, and errors in formulation can sometimes lead to poor results. Additionally, the lack of a proven treatment protocol has resulted in significant variations in how the drug is used and in treatment outcomes. We hope that our new robust findings with polihexanide 0.08 percent will revolutionize AK treatment by improving access and treatment consistency, and by addressing patients’ unmet needs.”

The Phase 3 randomized controlled double-blind clinical trial followed a Phase 1 trial in healthy volunteers, which demonstrated the safety of a significantly higher concentration (0.08 percent) of polihexanide. The Phase 3 trial adhered to the guidance provided by the European Medicines Agency and compared the effectiveness and safety of a high concentration of polihexanide (0.08 percent) as a standalone treatment to a commonly used combination therapy, which combines a lower dose of PHMB (0.02 percent) with propamidine. All trials were sponsored and funded by Italian pharmaceutical company SIFI, with partial co-funding from the European Commission.

The study involved the analysis of 127 individuals receiving AK treatment at six hospitals across Europe (England, Italy, and Poland).

The researchers found both formulations to be highly effective when used in accordance with the detailed drug delivery protocol, achieving medical cure rates of 110/127 (87 percent) overall and for each treatment individually. This means that 87 percent of individuals were cured of AK without requiring surgery, which is one of the highest cure rates ever reported for AK. The treatment failure rate was 17/127 (13.4 percent), almost half of whom required therapeutic corneal transplant surgery. The overall transplant surgery rate of 8/127 (6.3 percent) is one of the lowest reported in any case series of AK.

The researchers explain that the widely recommended combination therapy was particularly effective in this trial because clinicians strictly adhered to a standardized treatment protocol. Furthermore, the new monotherapy has advantages over the combination therapy, as its simplicity reduces the risk of errors in practice.

Dr. Vincenzo Papa (Head of Scientific Affairs at SIFI) and co-author of the study said: “This publication in Ophthalmology, the leading peer-reviewed journal in our field, further encourages our continued efforts to make polihexanide 0.08 percent (AkantiorĀ®) available to patients with AK, as the first approved orphan medicinal product. Given the significant burden of the disease and the high level of unmet medical need, we are proud of the high efficacy outcomes achieved in this robust trial, especially in comparison to the 60 percent efficacy rates reported with the current best treatment.”

Based on the comprehensive quality, preclinical, and clinical data generated over 15 years of research, SIFI is now seeking regulatory approvals for polihexanide 0.08 percent in Europe, the UK, and the US.

Juliette Vila Sinclair Spence, Rare Disease Patient Advocate & Chairwoman of the Acanthamoeba Keratitis Eye Foundation, commented: “Exciting news! AK Warriors (also known as patients) are now one step closer to receiving the first-ever product with a standardized protocol for Acanthamoeba keratitis. This is starting to bring light to the end of the tunnel.”

  • Published On Oct 27, 2023 at 05:41 PM IST

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