Visualization of multi-indication randomised control trial evidence to support decision-making in oncology: a case study on bevacizumab

BACKGROUND: An increasing number of oncology drugs are licensed for multiple indications, sharing of information across indications may help improve precision of estimates for a target indication where evidence may be immature. Visualising the accumulation of evidence and its characteristics across all indications can help inform policymakers on whether multi-indication synthesis methods should be considered, and guide expert elicitation on appropriate cross-indication assumptions. METHODS: The multi-indication oncology drug bevacizumab was selected as a case-study. We used visualisation methods including timeline, ridgeline and split-violin plots to display evidence and synthesis results across seven licensed cancer types, focusing on the evidence on overall and progression-free survival and the display of results from models with and without information sharing. RESULTS: The proposed displays allow for visualisation of key characteristics of the evidence to support the assessment of heterogeneity within and across indications and inform the feasibility of information-sharing models. LIMITATION: The lack of consistent reporting of data in trial reports limits the visualisation of some study characteristics. Trade-offs between plot readability and the level of detail to include were required. CONCLUSION: Clear graphical representations of the evolution and accumulation of evidence and synthesis results can provide a better understanding of the entire multi-indication evidence base which can inform judgements regarding the appropriate use of data within and across indications. Interactive plots could help overcome some of the current limitations. Implications: The proposed displays should be used to facilitate discussion with experts on the judgements required to assess feasibility of using information sharing methods to improve estimation of relative treatment effects in evidence synthesis approaches and health technology assessment.