Initial results from a first-in-human gene therapy trial on X-linked retinitis pigmentosa caused by mutations in RPGR.
Cehajic-Kapetanovic J., Xue K., Martinez-Fernandez de la Camara C., Nanda A., Davies A., Wood LJ., Salvetti AP., Fischer MD., Aylward JW., Barnard AR., Jolly JK., Luo E., Lujan BJ., Ong T., Girach A., Black GCM., Gregori NZ., Davis JL., Rosa PR., Lotery AJ., Lam BL., Stanga PE., MacLaren RE.
Retinal gene therapy has shown great promise in treating retinitis pigmentosa (RP), a primary photoreceptor degeneration that leads to severe sight loss in young people. In the present study, we report the first-in-human phase 1/2, dose-escalation clinical trial for X-linked RP caused by mutations in the RP GTPase regulator (RPGR) gene in 18 patients over up to 6 months of follow-up (https://clinicaltrials.gov/: NCT03116113). The primary outcome of the study was safety, and secondary outcomes included visual acuity, microperimetry and central retinal thickness. Apart from steroid-responsive subretinal inflammation in patients at the higher doses, there were no notable safety concerns after subretinal delivery of an adeno-associated viral vector encoding codon-optimized human RPGR (AAV8-coRPGR), meeting the pre-specified primary endpoint. Visual field improvements beginning at 1 month and maintained to the last point of follow-up were observed in six patients.