OBJECTIVES: Economic assessments are of utmost importance in health policy to inform the allocation of scarce resources. However, these economic assessments often involve many uncertainties. One of these important uncertainties is the duration of treatment effect. Typically a treatment effect is shown within a study, yet it is unclear whether this treatment effect would hold after the duration of the study. To deal with this type uncertainty, the incorporation of treatment waning is recommended. Although this recommendation is in place, it remains unknown whether this has been frequently used in pharmaceutical submissions to Zorginstituut Nederland (ZIN). Therefore the aim of this study was to explore whether treatment waning was incorporated in past economic assessments.

METHODS: ZIN assessments of pharmaceutical submissions that included an economic assessment in the time period of 2020-2022 were obtained. Data was extracted regarding submission characteristics, disease area, type of pharmaceutical and type of model, amongst others. Most importantly, the method to incorporate treatment waning was extracted.

RESULTS: Preliminary results show that of the 36 included economic assessments, 15 (42%) included treatment waning. Six (17%) included treatment waning in the base-case analysis and 9 (25%) included treatment waning in a sensitivity analysis. The methods to incorporate treatment waning were: gradual decreasing OS after certain time point (n=7), decreasing treatment effect with a certain percentage (n=1), changing health states after certain years (n=3) and changing regression coefficients (n=1). In 3 cases ZIN recommended treatment waning but it was not included in the final submission.

CONCLUSIONS: The majority of Dutch submissions ignore treatment waning, and when it is included, various methods were used. Currently, no clear guidelines on how and when to incorporate treatment waning are available. Future research should explore more robust methodologies to incorporate treatment waning in economic assessments.