OBJECTIVES: Gene therapies (GTs) are often designed to deliver lasting (or life-long) effects from a single dose. The length of GT clinical trials available for payer assessments is generally shorter than the duration of expected benefit. Supportive evidence (evidence other than clinical trial data) is being increasingly used to reassure payers on GT durability. This research aims to understand the extent to which European payers view the use of supportive evidence to evaluate GT durability.

METHODS: Interviews were held with former payers (n=3 per country) from England (ex-NICE), France (ex-TC/CEPS), Germany (ex-GB-A/GKV-SV), Italy (ex-AIFA/regional payers), Spain (ex-AEMPs/regional payers) and Switzerland (ex-FOPH). When prompted, respondents commented on the relative acceptability and importance of supportive evidence types in the estimation of durability: non-comparative long-term follow up (LTFU), real-world evidence (RWE), pre-clinical data, regression-based modelling, analog data, clinical expert opinions, and clinical consensus.

RESULTS: Across markets, the concept of durability was rated as important for GT decision-making, with most payers ranking durability as important as efficacy. LTFU, RWE, regression-based modelling, analog data and clinical consensus are likely to be the most impactful supportive evidence types in European markets (to varying degrees). LTFU and RWE were perceived to be the most important supportive evidence types, with pre-clinical data considered the least important. Payers from Italy, Spain, England and Switzerland showed a preference for all available evidence types being submitted, if positioned appropriately with adequate justification. In Germany and France, supportive evidence other than LFTU and RWE was considered of less value.

CONCLUSIONS: Based on payer insights, supportive evidence for GT durability is expected to be accepted and likely valued in most studied markets. To complement clinical data in payer assessments of GT durability, manufacturers should consider a broad supportive evidence package which reflects market-specific differences in the acceptability and importance of evidence types.