Presentation (CTI)

OBJECTIVES: Surrogate endpoints, used in place of final patient-relevant outcomes such as overall survival (OS) or health-related quality of life (HRQoL), increasingly inform reimbursement decisions and economic models, risking that a surrogate effect does not translate into patient benefit or that a cost-per-QALY estimate misstates value. The 2026 ISPOR Good Practices Task Force recommends evaluating surrogates across three evidence levels (biological plausibility, individual-level, trial-level) and integrating validation and related uncertainty with economic modelling. We assessed how far Dutch HTA practice (Zorginstituut Nederland, ZIN) currently reflects this.
METHODS: All clinical and economic dossiers from 2025 ZIN reimbursement assessments were reviewed. For each recommendation it was recorded whether it rested on a final outcome or not, and if not, whether the surrogacy of the outcome was evaluated and to what extent.
RESULTS: For 2025, 62 clinical dossiers and 18 economic dossiers were identified. In clinical assessments only 11 recommendations relied on a final endpoint (10 OS, 1 OS and HRQOL). Of the rest, only 7 evaluated surrogacy, while 38 relied on outcomes deemed patient-relevant without assessing how they related to OS or HRQOL. 6 assessments were excluded as they had issues around appropriateness of evidence source. In the economic dossiers, 11 models relied on modelling of final OS from the trial. In 3 other models, OS was informed by a surrogate endpoint, but surrogacy was only evaluated in 2 of these. In the remaining 5, incremental QALYs arose from time in higher-utility health states rather than OS gains. In none of these, surrogacy between intermediate outcomes and HRQoL was evaluated.
CONCLUSIONS: Dutch HTA practice in 2025 was not yet aligned with ISPOR good-practice recommendations: surrogates frequently informed decisions without trial-level validation, were assessed inconsistently, and were rarely integrated into economic modelling. Substantial changes in reporting will be needed to align with ISPOR good practices recommendations.