New Treatments Emerge for Retinitis Pigmentosa

A wave of novel gene therapies are under development as treatments for patients with retinitis pigmentosa (RP), following on the approval of voretigene neparvovec in late 2017. Each new therapy is being developed for a specific subpopulations of patients with RP, similar to the selection of those with RPE65 mutations for voretigene neparvovec.

A large number of these agents are still in preclinical studies; however, a handful of gene therapies are currently in phase 1/2 clinical trials, each geared at a highly selective subpopulation of patients. These agents include RST-001, which is geared toward channelrhodopsin, SAR-421869 (also called UshStat), aimed at the MYO7A gene, AAV-RPGR, targeting the RPGRgene, and recently HORA-PDE6B for patients with PDE6β-mutated RP.

An update on HORA-PDE6B was presented at the 2018 ARVO annual meeting. The poster presentation contained patient characteristics for the first 3 individuals enrolled in the study, which is hoping to include 12 total participants. The ages of patients ranged from 43 to 54 years and all had rod cone dystrophy related to the PDE6β gene mutation. Two of the three patients had photophobia and dyschromatopsia at baseline, and visual acuity was limited to hand movement for 1 patient.

"This clinical trial for PDE6β genes, or in other clinical trials for gene therapy for retinitis pigmentosa, I think for patients they want to be stable at first. If in gene therapy trials we can just delay blindness or if we have stop the decrease of the visual field it will be very great for patients," lead investigator of the HORA-PDE6B trial, Guylène Le Meur, MD, Ophthalmology Clinic, University Hospital of Nantes, Nantes, France, told MD Magazine at the conference.

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