Treatment Effect Waning Assumptions: A Review of National Institute of Health and Care Excellence Technology Appraisals.

OBJECTIVES

This study aims to review the National Institute of Health and Care Excellence (NICE) technology assessments to gain insights into the implementation of treatment effect (TE) waning, whereby the hazard or survival in an assessed technology converges to that of the comparator. This analysis aims to contribute to inform future guidance in this area.

METHODS

Technology appraisals published October 20, 2021 to September 20, 2023 were reviewed and data extracted on TE waning circumstances, methods, and rationale to compile a database based on 3 research questions: When are TE waning assumptions used? What methods are used? Why have the company/Evidence Assessment Group/committee preferred these methods?

RESULTS

Both the evidence assessment group/company and the committee included TE waning assumptions in 28 appraisals. There was no pattern of waning assumptions between shorter (<20 years) and longer (>20 years) time horizons. The most prominent time point for applying waning assumptions was at 5 years, with 30 out of 59 (50.8%) of the methods applied used 5 years. Stopping rules were used in 21 out of 30 (70.1%) of the appraisals for which the committee included waning, and waning assumptions were used more in oncology. The most common reason given for including TE waning assumptions was precedent from prior appraisals.

CONCLUSIONS

Considerable heterogeneity existed in both the methods used and justifications given for TE waning assumptions. This variability poses a risk of inconsistent decision making. Reliance on past appraisals emphasizes the necessity to advocate for evidence-driven approaches and underscores the demand for guidance on suitable methods for incorporating assumptions.