Health technology assessments of chimeric antigen receptor T cell therapies have been associated with a high uncertainty. Outcome-based payment arrangements (OBAs) aim to address uncertainty associated with the translation of trial outcomes to longer-term clinical outcomes. The extent to which OBAs alleviate uncertainty over the longer term is largely unknown.

There was a modest impact on reducing cost-effectiveness uncertainty under each OBA scenario compared with other sources of uncertainty in the model, whereas the potential financial uncertainty of an OBA was high. This emphasizes the need for careful consideration in making recommendations for OBAs, particularly given the resources and complexities associated with real-world data collection and payment arrangements.

If the main concern of governments and payors is the financial impact of high-cost therapies, then cost containment measures such as financial caps or price-volume agreements may be a more efficient approach to managing the high financial burden associated with cell and gene therapies compared with OBAs.