Optogenetics gene therapy may improve visual acuity in advanced retinitis pigmentosa
Patients with advanced retinitis pigmentosa who received intravitreal optogenetics gene therapy in a phase 1/2a study experienced improved visual acuity from baseline at 16 weeks, according to a speaker.
“Nanoscope’s polychromatic opsin is activated in ambient light, generates significant photocurrent and requires no goggles,” Santosh Kumar Mahapatra, MS, said at Retina Subspecialty Day at the virtual American Academy of Ophthalmology meeting.
The single intravitreal injection of vMCO-010 (Nanoscope) targets bipolar cells instead of retinal ganglion cells. Optogenetics gene therapy turns bipolar cells into light-sensing activated neurons in response to light, making them the new photoreceptors of the retina, Mahapatra said.
The study included 11 patients with advanced retinitis pigmentosa with no light perception or just perception of light in the study eye and no better than counting fingers in the fellow eye. Patients received either a low dose or high dose of vMCO-010 at baseline. Safety and visual acuity were assessed 16 weeks after the intravitreal injection.
The study included three patients who received a low dose of 1.75 × 1011 VG per eye and three patients who received a high dose of 3.5 × 1011 VG per eye. Once the safety of the high dose was confirmed, five patients were added to the high-dose cohort.
The therapy was well tolerated at 16 weeks. Five patients required no treatment, five patients experienced mild elevated IOP and were treated with topical glaucoma medication, and three patients experienced intraocular inflammation that subsided with topical steroids, Mahapatra said.
At 16 weeks, seven of eight patients in the high-dose cohort demonstrated a visual acuity improvement of 15 letters or more, and six of eight patients demonstrated an improvement of 30 letters or more from baseline. One patient in the low-dose group demonstrated a visual acuity improvement of 15 letters or more, he said.
Participants also demonstrated a mean improvement in latency from 30 seconds at baseline to 15 seconds at 16 weeks in a visually guided Y mobility test, he said.
“We observed a dose-dependent efficacy response at 16 weeks after a single intravitreal injection of MCO. With these encouraging results, Nanoscope is planning to commence a U.S. trial and follow-up studies in India,” Mahapatra said.
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Mahapatra SK. Phase 1/2a study of intravitreal optogenetics gene therapy for vision restoration in advanced retinitis pigmentosa. Presented at: American Academy of Ophthalmology annual meeting; Nov. 13-15, 2020 (virtual meeting).
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