PURPOSE: Introduce the audience to the role of surrogate outcomes in cost-effectiveness analysis intended to inform HTA, with a specific focus on how uncertainty should be dealt with using illustrative cases studies

DESCRIPTION: With the increasing use of flexible and accelerated regulatory pathways, the number of drug approvals using surrogate endpoints is increasing. Cost-effectiveness analysis requires quantitative evidence to model how changes to the surrogate outcome translate into changes to longer-term outcomes usually of interest to HTA bodies. When high quality evidence to support these relationships is missing, this can introduce considerable uncertainty in the evidence which can complicate decision making.

This workshop will present the ongoing work of an international collaboration of HTA agencies who are developing best practice guidance for the use of surrogate outcomes in cost-effectiveness analysis intending to inform HTA.

The discussion leader will present an overview of the working group’s rationale and the questions it is seeking to answer (10 minutes), which include the regulatory standards for validating surrogate endpoints, to what extent these standards meet requirements for using surrogate outcomes in economic modelling, and how surrogate outcomes should feature in the model conceptualisation stage of the cost-effectiveness model.

The discussants will then each present and discuss the complications that arise for a decision maker when high quality evidence to support surrogate relationships is missing using case studies (15 minutes per case study) such as a rare disease with high unmet need but with little evidence on long-term outcomes, a chronic condition where the surrogate relationship is well understood, and a condition with mixed evidence for the surrogate-long term relationship. These will be used for eliciting responses from the audience on how they believe the uncertainty should be dealt with and whether the evidence supporting the surrogate relationship is acceptable to inform decision making or not.