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 μm. 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.