Gene therapy for RPGR-associated RP effective at 6 months
Retinal sensitivity improved in patients with RPGR-associated X-linked retinitis pigmentosa treated with an AAV-RPGR gene therapy, a speaker said at the virtual American Society of Retina Specialists meeting.
“In our low- and intermediate-dose cohorts, we have achieved clinically meaningful improvements in retinal sensitivity across multiple metrics and modalities,” Michel Michaelides, BSc, MB BS, MD(Res), FRCOphth, FACS, said.
Because of their good safety profile, the low and intermediate doses are being taken forward in the ongoing randomized controlled dose-expansion phase of the study, he said.
Michaelides presented 6-month data from the phase 1/2 trial of AAV-RPGR including 10 patients with X-linked retinitis pigmentosa (RP). In the dose-escalation phase of the trial, three patients received AAV5-RPGR gene therapy at a low dose, four patients received the therapy at an intermediate dose, and three patients received a high dose. The researchers evaluated safety and tolerability of the therapy as the primary endpoint of the trial, but also assessed retinal sensitivity, visual function, functional vision and quality of life measurements as secondary endpoints, Michaelides said.
At 6 months, the low- and intermediate-dose cohorts demonstrated improvement or stability in retinal sensitivity. The low-dose cohort experienced a 0.69 dB improvement in mean retinal sensitivity, and the intermediate-dose cohort experienced a 1.02 dB improvement from baseline. The high-dose cohort did not experience similar improvements, Michaelides said.
“We have a good safety profile in our low- and intermediate-dose cohorts, and therefore these are the doses being taken forward in our ongoing randomized controlled dose-expansion phase of the study,” Michaelides said.
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Michaelides M, et al. AAV-RPGR gene therapy for RPGR-associated X-linked retinitis pigmentosa: 6-month results from a phase 1/2 clinical trial. Presented at: American Society of Retina Specialists annual meeting; July 24-26, 2020 (virtual meeting).
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