CC3 COST-EFFECTIVENESS ANALYSIS OF VORETIGENE NEPARVOVEC VERSUS BEST SUPPORTIVE CARE IN PATIENTS WITH RPE65-MEDIATED INHERITED RETINAL DYSTROPHY: A FRENCH HEALTHCARE SYSTEM PERSPECTIVE

Abstract

An economic model was developed to evaluate the cost-effectiveness of voretigene neparvovec (VN) compared to best supportive care (BSC) in individuals with RPE65-mediated inherited retinal dystrophy (IRD), from a French healthcare system perspective. Methods were based on HAS guidelines and international good research practices for modelling. A Markov model was used and included six health states (HS) based on AMA visual deficiencies classification: Moderate Visual Impairment (VI), Severe VI, Profound VI, vision limited to “counting fingers”, vision limited to “hand motion” to “no light perception” and death. A lifetime horizon was used. Transition probabilities were calculated based on the results from the VN phase III trial and a natural history study. The economic endpoints used in the model were blindness-free years (BFY) and quality-adjusted life years (QALYs). Utility data from a vignette study were used. Resource utilization and costs included: disease-related costs (diagnosis, mutation testing, paramedical care and follow-up), drug costs (acquisition, administration and adverse events), costs of medical transport and accommodation and death. Patients treated with VN stayed longer in better HS while patients in the BSC arm progressed more quickly to worse HS. The treatment with VN results in a gain of 11.7 BFY and 4.5 QALY versus BSC. The ICER for VN versus BSC was €51, 552 per BFY and €132, 607 per QALY. Deterministic and probabilistic sensitivity analyses generally showed consistency with base case findings. When additional scenarios were explored, ICERs were most sensitive to variations in the multi-state model parameters and duration of treatment effect. VN is the first gene therapy approved in RPE65-mediated IRD and represents a clinically significant advancement in the management of this disease. VN was associated with an important gain of QALYs versus BSC and can be considered a cost-effective therapy in this orphan disease.