Integrating early economic evaluation into the development of Target Product Profiles for new diagnostic tests

Background: Target Product Profiles (TPPs) for new medical tests specify desired properties and performance characteristics required to address an unmet clinical need. Early economic evaluation (EEE) has been used to identify the acceptable ranges for test specifications in the context of health technology assessment, but has not yet been utilised as part of the TPP methodology. Aim: To explore how EEE methods can be integrated into the TPP development process for new tests. Methods: A systematic review of TPPs for medical tests was conducted to establish current TPP methodology and limitations. The potential utility of integrating EEE into TPPs was explored via a case study example: a new rapid diagnostic test for Clostridioides difficile infection (CDI). An online survey of UK healthcare professionals was first conducted to map current practice and identify unmet clinical needs. An EEE, consisting of a discrete event simulation model, was then developed to determine minimum performance specifications for key test properties (diagnostic sensitivity, specificity) based on cost-effectiveness considerations. Results: The systematic review identified a typical three-step development process for TPPs for tests – scoping, drafting and consensus-building phases. The use of subjective data sources, poor methodological transparency and an oversight of clinical utility and cost-effectiveness considerations were identified as key limitations of current TPP methodology. A three-phase de novo approach was developed to derive minimum test performance specifications and maximum costs using a series of sensitivity analyses. In the case of a new rapid test for CDI, a minimum diagnostic sensitivity and specificity of 96% is required for the test for CDI to be cost-effective. Conclusions: EEE, in conjunction with stakeholder consultation activities, provides an evidence-based and transparent approach to informing certain TPP test characteristics. EEE should also help TPP developers to better understand how trade-offs between different test characteristics play out in terms of cost-effectiveness.