Introduction
Our webinar explored the use of expert prior elicitation techniques in clinical research, particularly in the context of Bayesian statistics. The event featured presentations from experts in the field, including Professor Thomas Jaki from the University of Regensburg and the University of Cambridge, Nigel Dallow from GSK, and statisticians from Phastar.
Introduction to Prior Elicitation
Yasin Desai, senior statistician at Phastar, opened the webinar by setting the scene for the discussion on prior elicitation. He emphasized the challenges of conducting randomized controlled trials (RCTs) in rare diseases due to constraints like budget, patient recruitment and ethical considerations. Bayesian methods could help by incorporating expert opinions and existing evidence to better quantify uncertainty and potentially reduce required sample sizes.
In Bayesian analysis, prior elicitation involves incorporating expert knowledge or external information about an unknown parameter into the analysis. Instead of assuming no prior knowledge or disregarding potential differences by pooling all patients together, prior elicitation allows for the flexible application of an “informative prior.” This prior reflects existing expert beliefs or data about the parameter of interest before observing new trial data, helping to inform and refine the analysis based on credible external insights. [1]
A Case Study for Rare Skin Disease
Professor Thomas Jaki presented a detailed case study on the elicitation of expert prior opinions for juvenile localized scleroderma, a rare skin disease. [2] He discussed the limitations of traditional RCTs in this context, as the rarity of the disease made it impractical to recruit the necessary number of patients. He explained how Bayesian clinical trials could be an alternative, allowing the use of prior expert knowledge to enhance the trial data. The elicitation process involved training experts in the Bayesian framework, conducting practice elicitation sessions, and arriving at consensus distributions through guided group discussions.
An Industry Perspective
Nigel Dallow from GSK provided an industry-focused perspective on the use of prior elicitation in drug development. He highlighted the importance of addressing uncertainty in drug development and how Bayesian methods can shed light on this uncertainty, particularly in scenarios where traditional RCTs are not feasible. His talk underscored the practical applications of prior elicitation techniques in making informed decisions during the drug development process.
Phastar Statisticians’ Insights
Giles Partington and Emily Foreman, expert statisticians from Phastar, shared their experiences with expert prior elicitation in clinical research. They discussed the work of Phastar’s prior elicitation team and the challenges they encountered in minimizing bias during the elicitation process. Their talk provided valuable insights into the practical aspects of applying Bayesian methods in clinical trials.
Conclusion
The webinar offered a comprehensive overview of the use of prior elicitation and Bayesian methods in clinical research. The case studies and industry insights provided a clear understanding of the challenges and opportunities in this area. The session highlighted these methods’ potential to enhance the design and execution of clinical trials, especially in rare diseases.
If you’re looking to explore how Bayesian methods and expert prior elicitation can transform your clinical trial design, our team at Phastar is here to help. Whether you’re facing challenges with rare disease trials or seeking to incorporate expert knowledge into your research, our statisticians and clinical trial experts can guide you through innovative solutions tailored to your needs.
References
[1] Thirard R, Ascione R, Blazeby JM, Rogers CA. Integrating expert opinions with clinical trial data to analyse low-powered subgroup analyses: a Bayesian analysis of the VeRDiCT trial. BMC Med Res Methodol. 2020 Dec 10;20:300. doi: 10.1186/s12874-020-01178-6.
[2] Desai, Y., Jaki, T., Beresford, M. W., et al. (2021). Prior elicitation of the efficacy and tolerability of Methotrexate and Mycophenolate Mofetil in Juvenile Localised Scleroderma [version 1; peer review: 2 approved]. AMRC Open Research, 3, 20. https://doi.org/10.12688/amrcopenres.12923.1
