An Economic Evaluation of Voretigene Neparvovec for the Treatment of Biallelic RPE65-Mediated Inherited Retinal Dystrophies in the UK

Introduction Voretigene neparvovec (VN) is a gene therapy and the first approved pharmacological treatment for biallelic RPE65 -mediated inherited retinal dystrophies (IRD), a rare condition that starts in early life and causes vision to progressively deteriorate towards complete blindness. In a phase III trial, treatment with VN significantly improved functional vision and visual function, and in October 2019 the National Institute for Health and Care Excellence (NICE) Highly Specialised Technologies (HST) process recommended VN for patients in England and Wales. We assessed the cost-effectiveness of VN compared with best supportive care (BSC) in individuals with biallelic RPE65 -mediated IRD in the UK. Methods A Markov model was developed to estimate the incremental cost per quality-adjusted life-year (QALY) gained for VN compared with BSC, from the perspective of the UK National Health Service and Personal Social Services. Phase III trial data were used to inform transition probabilities up to year 1, after which the treatment effect was assumed to be maintained for 40 years, followed by a decline in vision. A bespoke elicitation exercise involving clinical experts, patients and carers was conducted to estimate utility values for each model health state. Results At list price, VN is associated with incremental costs of £612,404 and incremental QALYs of 6.4, resulting in an incremental cost-effectiveness ratio (ICER) of £95,072 per QALY gained. Voretigene neparvovec is associated with a significant undiscounted QALY gain (20.5) and is therefore eligible for additional QALY weighting under the NICE HST process; an ICER of up to £205,000 per QALY gained could be considered cost-effective under this framework. Conclusion The results of the model show VN to be a cost-effective use of healthcare resources in the UK at list price. The availability of a commercial discount in the UK (as considered in the NICE appraisal) means that in reality the ICER will be even lower. Plain Language Summary Plain language summary available for this article.