OBJECTIVES: The EU regulation on Health Technology Assessment (HTA) comes into force in 2025, providing a permanent framework for joint clinical assessment (JCA) submissions. Overarching elements of uncertainty in HTA submissions, including the type, and quality, of evidence source and method of evidence synthesis were identified in a targeted literature review. The aim of this study was to develop a rating system to assess the acceptability of data and methods used to generate results from indirect treatment comparisons (ITCs) for JCA.

METHODS: Practical and methodological guidelines on quantitative evidence generation for JCA dossiers were identified, from resources developed by HTA co-ordination group, and analysed for accepted ITC methods. Study quality was assessed using Cochrane’s risk of bias questionnaire and ITC-relevant factors were assessed based on expert opinion.

RESULTS: The rating system involved three components. The first score was calculated including factors such as risk of bias tool outcomes, sample size, and study type. With each of the factors weighted to reflect its significance. The second score includes the exchangeability assumption, comprising study similarity, homogeneity, consistency, and geometry on a network level, which were rated in a second score. The final score includes appropriateness of statistical methods for ITC taking the availability of randomised/non-randomised evidence, individual patient data, and assumptions on treatment effect into account.

CONCLUSIONS: A rating system for quantitative evidence synthesis would provide a useful tool to predict the acceptability of ITC results in JCA dossiers and to anticipate and mitigate potential barriers in an early stage. However, other factors influencing acceptability such as unmet need or indication are currently unexplored and future research is needed to include these in a holistic rating system. Finally, the rating system will need to be tested on published dossiers to validate this approach.