The methodological framework of INCEPT is developed with the overall purpose of developing a modular core protocol describing the following:

1. The overaching design (a Bayesian, adaptive platform trial)
2. Processes for adding interventions (principles for stakeholder involvement and prioritization)
3. Processess for participant stratification, enrichment and adaptive allocation
4. Processess for testing intervantions between multiple interventions tested
5. Stopping criteria for interventions nested in different domains (based on regular adaptive analyses providing post-randomisation probabilities using Bayesian inference models and pre-defined criteria for superiority, inferiority, practical equivalence, futility, and/or at maximum pre-defined sample sizes for each domain)
6. A framework for planning and simulation adaptive trials (and adaptation within different domains, allowing selection of “optimal” design characteristics based on multiple metrics)
7. Subgroup analyses and assessment of heterogeneous intervention effects in multiple groups in the trial
8. Outcome selection and priorisation (a core outcome set is developed with appropriate stakeholder-involvement)

The core protocol will describe the overall platform trial design and the different options that may be selected for individual domains on the platform (sets of related interventions tested). Domain-specific appendices will be written, describing the exact interventions assessed and methodological choices specific for each domain.