Challenges in Value Assessment for One-Time Gene Therapies for Inherited Retinal Diseases: Are We Turning a Blind Eye?

Objectives: X-linked retinitis pigmentosa (XLRP) is a rare inherited retinal disease with no available treatment. Gene therapies in clinical trials will pose challenges for health technology assessment (HTA) if found to be safe and effective. We evaluated 2 of these challenges, namely acceptability and difficulties in assessing value beyond short-term patient health and healthcare savings and discounting in economic evaluation.

Methods: We conducted a narrative literature review on the socioeconomic burden of XLRP to identify relevant components of value for a hypothetical gene therapy from a societal perspective and to assess their relative importance. We compared the resulting value profile against the value frameworks of three European HTA agencies. We also reviewed their guidelines on discounting and potential discounting issues specific to XLRP.

Results: Much of the societal value of an XLRP gene therapy is likely to originate from productivity effects, carer spillovers, and value elements related to patient uncertainty. The evidence on these effects, however, is often limited, making it difficult for HTA agencies to assess them. Cost-effectiveness results are likely to be highly sensitive to the discount rate, and discounting will compound the effects of omitting important sources of value.

Conclusions: We have identified and detailed important components of societal value, key evidence gaps, and potential discounting issues for an XLRP gene therapy, which can inform future value assessments. Many of these may apply to gene therapies in other disease areas. Revisiting existing HTA approaches is recommended to ensure these are fit for purpose for such new classes of treatment.