Nanoscope gene therapy clears ph2 retinitis pigmentosa trial

eye health
Ryoji Iwata

Nanoscope Therapeutics has reported data from a mid-stage clinical trial that suggests its optogenetic therapy based on light-sensitive molecules is an effective treatment for incurable eye disease retinitis pigmentosa (RP).

The treatment, called MCO-010 (sonpiretigene isteparvovec), comprises a gene that codes for the ambient light-sensitive MCO protein carried by an adeno-associated virus (AAV) vector, which is administered into the eye by intravitreal injection.

The rationale is that MCO can restore the light-detecting function of retinal cells that are damaged in RP, regardless of the underlying mutation that has caused the disease. Approximately 100,000 people in the US and an estimated 2 million people worldwide suffer from RP, making it the leading cause of inheritable blindness.

That’s important because thousands of mutations across more than 50 genes have been associated with RP, so a gene therapy that targets just one mutation would only work in a subset of patients. The new data is “a pivotal moment for the field of mutation-agnostic gene therapy,” according to Nanoscope’s chief scientific officer, Samarendra Mohanty.

Other gene therapies for RP - from companies including Biogen, Syncona, SparingVision ,and ProQR Therapeutics - are targeting specific mutations in the RPGR, USH2A, and RHO genes, for example.

In its first major efficacy test, MCO-010 showed “clinically meaningful” improvements in vision-guided mobility or object recognition in 16 out of 18 people with severe vision impairment due to RP, compared to four of nine patients in a placebo group who underwent a sham injection.

The main outcome measure used in the trial was the multi-luminance y-mobility test (MLYMT), which measures how well patients are able to navigate between LED lights in a room, at varying levels of brightness or luminance.

All told, 12 of 18 MCO-010-treated patients had a two-point or greater improvement on luminance levels using the MLYMT scale, and in some cases the improvements were “substantial”, according to study investigator Victor Gonzalez of the Texas-based Valley Retina Institute.

Several patients were able to walk in the clinic with more certainty, after a single treatment, which he described as “transformative” and “unprecedented”.

“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,” said Gonzalez, who also pointed to the gene therapy’s favourable safety profile, with no serious or severe ocular or systemic adverse events reported.

Nanoscope is also testing MCO-010 for patients with another sight-robbing condition called Stargardt disease in the phase 2 STARLIGHT trial, due to generate results in the summer.

Photo by Ryoji Iwata on Unsplash