Real-world outcomes of Voretigene Neparvovec: a single-centre consecutive case series

Purpose To present functional and anatomical outcomes of subretinal therapy with Voretigene Neparvovec (VN) in patients treated in one of the four specialist UK gene therapy centres. Methods Single-centre, retrospective case series of patients affected by an inherited retinal dystrophy (IRD) caused by a pathogenic biallelic RPE65 mutation and treated with VN. Complete ophthalmic examination was planned preoperatively and 2, 4 and 8 weeks and 3, 6, 12, 18 and 24 months after surgery, and included visual acuity (VA) assessment (normal and low luminance), colour vision, contrast sensitivity, dark-adapted full-field stimulus threshold, macular optical coherence tomography (OCT) and fundus autofluorescence. Results Fourteen eyes of 8 patients were included with a mean follow-up of 26 months. Mean final VA improved by 2 lines, and improvements were noted in most other functional tests. Central retina thickness (CRT) remained fairly stable in the majority of patients, whereas 2 eyes experienced a reduction >30 mu m. The status of ellipsoid band and external limiting membrane remained stable in all patients, except one. Peripapillary atrophy (PPA) was present in 5 eyes of 3 patients at the baseline; postoperative progression was noted in both eyes of one patient. No patient developed new PPA or chorioretinal atrophy (CRA) involving the macular area after treatment. Five eyes of 3 patients developed CRA at the retinotomy site, that progressed in 3 of them. Conclusions Our study confirmed the effectiveness of subretinal VN therapy in terms of improvement of visual function. CRA was confirmed as a common postoperative complication, with limited functional impact.