Presentation (CTI)

OBJECTIVES: In the absence of clinical data, structured expert elicitation (SEE) offers a systematic method of quantifying expert knowledge and uncertainty regarding complex parameters. This study aimed to obtain and evaluate expert estimates of expected outcomes for “difficult-to-treat” Crohn’s disease treatment in preparation for subsequent early health technology assessment (HTA).
METHODS: The study aimed to recruit 5 to 10 gastroenterologists from 6 European countries. Respondents predicted the relative effect of an experimental, RNA-based therapy compared with upadacitinib in relation to endoscopic response and closure of external fistula openings following 12- and 52-weeks of treatment. The elicited judgements were then aggregated using linear opinion pooling, with additional weighting applied according to each expert’s years of experience, to derive the overall pooled probability density functions.
RESULTS: 10 respondents were recruited from 4 countries (UK, Ireland, Italy and Denmark). Based on the SEE, the difference in mean (95% CI) between RNA-based therapy and upadacitinib in the percentage of patients with endoscopic response and fistula closure was 1.2% (-5.8, 8.3) at 12-weeks [absolute rates of 9.6% vs. 8.0%], and 0.6% (-10.4, 11.5) at 52 weeks [11.1% vs. 11.0%]. For endoscopic response alone, these were -3.7% (-17.3, 9.9) and -2.0% (-16.6, 12.7) respectively; and for fistula closure alone, -4.0% (-11.9, 4.0) and -0.8% (-8.9, 7.2), respectively. These results were consistent in a sensitivity analysis in which responses were weighted by respondents’ clinical experience.
CONCLUSIONS: Experts recruited for the study were cautious about predicting any therapeutic advantage of the experimental RNA-based therapy over upadacitinib for outcomes in fistulizing Crohn’s disease. Respondents reported that the task was difficult, and this may explain the challenges with recruitment. By offering a structured framework for quantifying uncertainty explicitly, belief elicitation has an emerging role in the context of treatments at an early stage of development. Clinical studies are needed to validate this elicitation approach.