What are the best biomarkers and endpoints for future trials?


The ‘Usher Action Rijnsbrug’ group of friends present the check to Dr. Suzanne Yzer. From left to right; Marjolein, Liesbeth, Suzanne, Annemarie

Usher syndrome, characterized by sensorineural hearing loss and progressive Retinitis Pigmentosa (RP), presents a significant challenge for the medical community. With the most involved gene, USH2A, treatments for Retinitis Pigmentosa are becoming increasingly promising. The use of correctly chosen endpoints will prevent unnecessary failures of potentially effective treatment studies and accelerate the development of treatments.

Thanks to the years of unwavering enthusiasm and dedication of the ‘Usher Actie Rijnsburg’ group, Stichting Ushersyndroom can financially support an important study into the right biomarkers and endpoints.

Correlation between structure and function
In this study, led by Dr. Suzanne Yzer, ophthalmologist at Radboud University Medical Center in the Netherlands, researchers aim to examine the retinas of patients with Usher syndrome by combining existing ophthalmic examinations with newly developed imaging techniques. The combined information will provide a more detailed correlation between the structure and function of the retina, yielding essential data for a comprehensive analysis. This will enable the identification of the best biomarkers and endpoints for clinical trials for Usher syndrome patients. Biomarkers and endpoints that will aid in treatment trials (clinical trials), ensuring that outcomes and information are indisputable and provide evidence of treatment effectiveness.

“Correctly chosen endpoints help prevent the unnecessary failure of a potentially groundbreaking treatment study.”
Dr. Suzanne Yzer, Ophthalmologist at Radboud University Medical Center

A poorly designed study or wrongly chosen biomarker or endpoints can lead to years of delay before the therapy becomes available to patients. This is not only a significant disadvantage for the specific treatment but will also deter investors from supporting new studies.

Incorrect endpoints
The failure of a treatment study does not necessarily mean that the investigated therapeutic treatment is ineffective. Studies may fail because of inaccurately chosen inclusion criteria or endpoints. In August 2022, ProQR’s clinical trial was halted for this reason. The endpoints for another clinical trial (for LCA) were not accurately defined, resulting in them not being met. Investors withdrew, leading to insufficient funding to continue the clinical trial for USH2A exon 13.
The clinical trial has since been restarted; Laboratoires Théa (Théa) has taken over the study.

Existing and new imaging tools
With the first clinical trials on the horizon, it is crucial to select the right biomarkers and endpoints. Radboudumc has conducted a large natural history study in a large group of patients with mutations in USH2 genes, the CRUSH study, and the RUSH2a study. Results are expected in the fall of 2024. Since the start of these studies, progress has been made with existing and newly developed imaging tools, such as “Adaptive Optics” and the “High Magnification Module” lens.

Increasing opportunities
The current study focuses on identifying the most reliable biomarkers and endpoints for future therapeutic studies in Usher syndrome type 2. By identifying better endpoints, the chances of demonstrating treatment effectiveness will be increased, helping to advance the development of treatments. This will also make it more attractive to accelerate the implementation of new clinical studies, such as gene replacement therapy for Usher syndrome, including minigenes for USH2A and USH2C, and exon excision therapy.

This will ultimately benefit all patients with Usher syndrome. The goal is to achieve successful treatment and administer the drug or therapeutic treatment in the earlier stages of the disease, thus preventing severe loss of photoreceptors. The findings will be published in scientific journals and will contribute to the advancement of gene-specific therapies for retinal diseases.

Thanks to the Usher Action Rijnsburg and the co-financing from the Vaillantfonds and the Aanmoedigingsfonds van de Koninklijke Facultatieve the Stichtig Ushersyndroom can financially support this research.This project is budgeted at € 226.000,- and will last for three years.

Friends group of Liesbeth
‘Usher Actie Rijnsburg’ is a friends group that takes action for their friend Liesbeth and other people with Usher syndrome. They organize various activities and an annual event to raise as much money as possible.