Nanoscope Therapeutics has reported promising results from its Phase 2 clinical trial evaluating MCO-010 (sonpiretigene isteparvovec), an optogenetic gene therapy for retinitis pigmentosa (RP), demonstrating significant vision improvements in patients with severe visual impairment.
The trial showed that 16 out of 18 patients treated with MCO-010 experienced clinically meaningful improvements in vision-guided mobility or object recognition, compared to only four of nine patients in the placebo group who received a sham injection.
Novel Mutation-Agnostic Approach
MCO-010 represents a breakthrough in treating RP by employing a mutation-agnostic approach. The therapy delivers a gene encoding the ambient light-sensitive Multi-Characteristic Opsin (MCO) protein via an adeno-associated virus (AAV) vector, administered through a single intravitreal injection.
This approach is particularly significant because RP can be caused by thousands of mutations across more than 50 genes. Traditional gene therapies targeting specific mutations would only benefit subsets of patients, whereas MCO-010 aims to restore retinal function regardless of the underlying genetic cause.
"This is a pivotal moment for the field of mutation-agnostic gene therapy," said Samarendra Mohanty, PhD, Chief Scientific Officer at Nanoscope Therapeutics. "The positive results of our clinical trials represent a major step forward in treating inherited retinal diseases."
Significant Clinical Outcomes
The primary outcome measure in the Phase 2 trial was the multi-luminance y-mobility test (MLYMT), which assesses patients' ability to navigate between LED lights at varying brightness levels. Twelve of the 18 patients receiving MCO-010 achieved a two-point or greater improvement on luminance levels using the MLYMT scale.
Dr. Victor Gonzalez of the Texas-based Valley Retina Institute, a study investigator, described the results as "transformative" and "unprecedented," noting that several patients were able to walk with greater confidence after a single treatment.
"These participants who were living with severe vision impairment due to RP now have an improved quality of life, very different from before receiving MCO-010," Gonzalez stated.
Detailed Clinical Evidence
Additional clinical data published in Molecular Therapy provided further evidence of MCO-010's efficacy. In an earlier Phase 1/2a trial involving four RP patients with ABCA4 variants, all participants showed improvement in best-corrected visual acuity (BCVA) at week 12, as measured by Freiburg Visual Acuity Testing (FrACT).
The patients, who were legally blind with hand-motion to light-perception vision before treatment, received a single intravitreal injection of 100 μl AAV2-MCO-010 in their worse-seeing eye after prophylactic steroid treatment.
Mean visual field index (VFI) also increased following treatment, though with some variability among patients. One patient experienced inflammatory keratic precipitates that temporarily affected vision but resolved with topical steroid drops.
Safety Profile
Across the clinical studies, MCO-010 demonstrated a favorable safety profile. No serious or severe ocular or systemic adverse events were reported in the Phase 2 trial. Similarly, the Phase 1/2a trial reported no serious adverse events or suspected unexpected serious adverse reactions to the treatment.
Broader Applications
Retinitis pigmentosa affects approximately 100,000 people in the US and an estimated 2 million people worldwide, making it the leading cause of inheritable blindness. Nanoscope is also testing MCO-010 for Stargardt disease, another sight-robbing condition, in the ongoing Phase 2 STARLIGHT trial, with results expected this summer.
Dr. Vinit B. Mahajan, professor and vice chair for research in the Department of Ophthalmology at Stanford University, emphasized the significance of these findings: "Our study represents a pivotal milestone in the treatment of inherited retinal degenerations, demonstrating that optogenetics can successfully restore vision in blind patients, regardless of their genetic mutation. The ability to restore vision with a single intravitreal injection marks a significant step toward developing a universal treatment for retinal degenerative diseases."
As the field of gene therapy continues to evolve, Nanoscope's approach offers hope for a broader population of patients with inherited retinal diseases who previously had limited treatment options.
