PAtient-Centric epilepsy clinical trIal model For Improved health outcomes using Cannabidiol (PACIFIC study)—a methodology for developing patient-centred clinical trials in rare epilepsy syndromes

Abstract Background: Clinical trials for rare epilepsies face substantial methodological and ethical challenges. Small and heterogeneous populations, coupled with limited validated outcome measures, often render traditional designs underpowered and unable to capture outcomes that are meaningful to patients and their families. Innovative approaches—such as decentralised, adaptive, and participatory designs—offer potential solutions but have rarely been systematically applied in this context. Methods: We employed an exploratory three-phase sequential mixed-methods design to co-design a patient-centred clinical trial protocol for rare epilepsies in