Current Management of Patients with RPE65 Mutation Associated Inherited Retinal Degenerations in Europe: Results of a 2-Year Follow-Up Multinational Survey

Abstract

Introduction: The aim of this study was to evaluate the current management of RPE65 biallelic mutation-associated inherited retinal degeneration (RPE65-IRD) in Europe since market authorization of voretigene neparvovec (VN, LuxturnaTM) in 2018. By July 2022, over 200 patients have been treated outside the USA, of whom about 90% in Europe. We conducted among all centers of the European Vision Institute Clinical Research Network (<ext-link ext-link-type="uri" xlink:href="http://EVICR.net" xmlns:xlink="http://www.w3.org/1999/xlink">EVICR.net</ext-link>) and health care providers (HCPs) of the European Reference Network dedicated to Rare Eye Diseases (ERN-EYE) the second multinational survey on management of IRDs in Europe elaborated by <ext-link ext-link-type="uri" xlink:href="http://EVICR.net" xmlns:xlink="http://www.w3.org/1999/xlink">EVICR.net</ext-link> with a special focus on RPE65-IRD.

Methods: An electronic survey questionnaire with 48 questions specifically addressing RPE65-IRD (2019 survey 35) was developed and sent by June 2021 to 95 <ext-link ext-link-type="uri" xlink:href="http://EVICR.net" xmlns:xlink="http://www.w3.org/1999/xlink">EVICR.net</ext-link> centers and 40 ERN-EYE HCPs and affiliated members. Of note, 11 centers are members of both networks. Statistical analysis was performed with Excel and R.

Results: The overall response rate was 44% (55/124); 26 centers follow RPE65 biallelic mutation-associated IRD patients. By June 2021, 8/26 centers have treated 57 RPE65-IRD cases (1-19/center, median 6) and 43 planned for treatment (range 0-10/center, median 6). The overall age range was 3-52 years, and on average 22% of the patients did not (yet) qualify for treatment (range 2-60%/center, median 15%). Main reasons were too advanced (range 0-100, median 75%) or mild disease (range 0-100, median 0). Eighty-three percent of centers (10/12) that follow RPE65 mutation-associated IRD patients treated with VN participate in the PERCEIVE registry (EUPAS31153, <ext-link ext-link-type="uri" xlink:href="http://www.encepp.eu/encepp/viewResource.htm?id=37005" xmlns:xlink="http://www.w3.org/1999/xlink">http://www.encepp.eu/encepp/viewResource.htm?id=37005</ext-link>). Quality of life and full-field stimulus test improvements had the highest scores of the survey-reported outcome parameters in VN treatment follow-up.

Conclusion: This second multinational survey on management of RPE65-IRD by <ext-link ext-link-type="uri" xlink:href="http://EVICR.net" xmlns:xlink="http://www.w3.org/1999/xlink">EVICR.net</ext-link> centers and ERN-EYE HCPs in Europe indicates that RPE65-IRD might be diagnosed more reliably in 2021 compared to 2019. By June 2021, 8/26 centers reported detailed results including VN treatment. Main reasons for non-treatment were too advanced or mild disease, followed by absence of 2 class 4 or 5 mutations on both alleles or because of a too young age. Patient satisfaction with treatment was estimated to be high by 50% of the centers.

Keywords: ERN-EYE HCPs; EVICR.net clinical centers; Europe; Inherited retinal degenerations; Management; RPE65.