Dutch biotech firm ProQR Therapeutics has started dosing patients in a Phase II/III clinical trial of its investigational RNA-based oligonucleotide sepofarsen to treat Leber’s Congenital Amaurosis 10 (LCA10).

LCA10 is a common cause of blindness in children due to genetic disease. The CEP290 gene mutations are responsible for the condition, with the p.Cys998X mutation being the most common.

Currently, LCA10 lacks approved treatments that target its underlying cause.

Sepofarsen is intended to restore normal CEP290 mRNA, which would allow the generation of normal CEP290 protein by binding to the mutated pre-mRNA site.

The therapeutic is formulated for intravitreal injections in the eye.

“We are breaking new ground and paving the way for new treatments in multiple severe inherited retinal diseases.”

Dubbed ILLUMINATE, the Phase II/III trial will assess the drug in patients with one or two p.Cys998X mutation copies in the CEP290 gene and a baseline best corrected visual acuity (BCVA) of 3 LogMAR or better.

The 24-month, randomised, prospective, double-masked, sham-controlled study will initially recruit 30 adults and children aged eight and above.

ProQR Therapeutics chief medical officer Aniz Girach said: “The start of the ILLUMINATE trial marks an important milestone towards our goal of bringing this novel and most advanced therapy for LCA10 to patients.

“With the ongoing trials in LCA10 and Ushers syndrome type II, and the start of our clinical programme for adRP later this year, we are breaking new ground and paving the way for new treatments in multiple severe inherited retinal diseases.”

The primary endpoint of the ILLUMINATE trial, which is being conducted in North America and selected European sites, is the mean change in BCVA from baseline in the sepofarsen arms compared to the control arm.

The study will also monitor a mobility course endpoint and other endpoints such as full field stimulus testing, ocular instability, and optical coherence tomography.

Changes in the patients’ quality of life will also be tracked. The company expects to report trial results by the end of next year.