Rare Daily Staff
Nanoscope Therapeutics, a clinical-stage biotechnology company developing gene therapies for the treatment of retinal diseases, reported that vision improvements for all evaluated advanced retinitis pigmentosa patients persisted through one year following a single intravitreal injection of its optogenetic gene therapy MCO in a phase 1/2a clinical study.
Retinosis pigmentosa (RP) encompasses a group of rare genetic disorders in which the retina’s photoreceptor cells degrade over time, leading to impaired vision and eventual blindness. These disorders are believed to be linked to over 60 different gene mutations.
In normal eyes, opsins are expressed by photoreceptor cells and intrinsically photosensitive retinal ganglion cells (ipRGCs) in the retina, and when activated by light they trigger the physiological process of vision. Nanoscope utilizes multi-characteristic opsin (MCO) molecules to re-sensitize the degenerated retina of RP sufferers to restore vision in an ambient light environment.
In the study, three patients received low dose and eight received a high dose of the MCO gene therapy per eye. Florescence imaging of retina revealed successful gene transduction. At completion, 6 out of 7 (86 percent) high dose MCO-therapy subjects gained greater than 0.3 logMAR (15 letters). Due to COVID-19, one of the high dose subjects was not evaluated after 31 weeks of treatment.
“The safety and efficacy results from the clinical study have demonstrated that the benefit-risk balance is strongly in favor of MCO for the treatment of vision loss due to RP. The patients have improved irrespective of underlying gene mutation(s) that caused the disease,” said Nanoscope CMO and ophthalmologist Sai Chavala.
All subjects had objective and subjective improvement in functional vision. The shape discrimination accuracy improved to greater than 90 percent in all subjects compared to baseline. Further, the performance in two different mobility tests improved by 50 percent reduction in time to touch lighted panel. These test outcomes were highly correlated with improved patient reported outcomes.
“After MCO-treatment, the patients reported long-lasting improvements in outdoor light sensitivity and daily activities. We were pleasantly surprised that after eight weeks of treatment, some subjects could attend their follow-up visits during the study without the assistance of a chaperone. Some of the patients even gained the ability to read letters on a wall or even the large text in a newspaper, use a cell phone, watch television, and could even thread a needle.” said Principal Investigator Santosh Mahapatra, an ophthalmologist and eye surgeon.
Nanoscope’s RP gene therapy, which has received orphan drug designation from the U.S. Food and Drug Administration, uses a proprietary AAV2 vector to deliver the MCO genes into the retina. This mutation-independent gene therapy involves a single injection through the eye administered in a doctor’s office.
“We expect to begin the first randomized, placebo-controlled, double-masked phase 2b multi-center optogenetic trial in the United States this summer to further validate our gene therapy’s ability to improve clinically meaningful vision in RP patients,” said Nanoscope CEO Sulagna Bhattacharya. “If successful, it will be the first-ever restorative drug for millions of RP patients worldwide.”