Cost-effectiveness of Voretigene Neparvovec-rzyl vs Standard Care for RPE65-Mediated Inherited Retinal Disease

Voretigene neparvovec-rzyl, the first gene therapy approved by the US Food and Drug Administration, was approved for the treatment for RPE65-mediated inherited retinal disease (IRD) in December 2017. This gene therapy is associated with high up-front costs and high efficacy, although of unknown duration, and its cost-effectiveness has not been assessed with RPE65 IRD-specific, longitudinal, patient-observation-level data.

To assess the incremental cost-effectiveness ratio (ICER) of voretigene neparvovec-rzyl compared with standard care for RPE65-mediated inherited retinal disease.

In this economic analysis, a health state transition model based on visual acuity and field with a lifetime horizon was developed to estimate the cost-effectiveness of voretigene neparvovec-rzyl. The model was populated with data from a clinical trial of voretigene neparvovec-rzyl to evaluate treatment outcome and a natural history study of RPE65-mediated IRD to examine disease progression. Direct costs were derived from the literature. Indirect costs, including educational attainment, productivity, caregiver burden, and governmental programs, were estimated using published literature and data analysis of public national surveys. A health utility vignette study specific to RPE65-mediated IRD was used for health utility inputs. The cost-effectiveness study described in this article was conducted from September 15, 2017, to August 23, 2018.

Bilateral voretigene neparvovec-rzyl therapy or standard care.

Incremental cost-effectiveness ratio.

The model population included 70 patients with RPE65-mediated IRD, with a mean age of 15 years; 42 of 70 patients (60%) were female. In the base case, voretigene neparvovec-rzyl compared with standard care was associated with lower total costs ($2.2 million vs $2.8 million) and higher quality-adjusted life-years (18.1 vs 8.6). Voretigene neparvovec-rzyl remains cost-effective if at least 8.8% of the long-term treatment effect continues after year 3 when including indirect costs and 43.3% when excluding indirect costs, assuming a cost threshold of $150 000 per quality-adjusted life-year.

Results of this study suggest that voretigene neparvovec-rzyl is cost-effective compared with standard care when using a lifetime horizon, excluding indirect costs, and using a threshold of $150 000 per quality-adjusted life-year.