Table 1.

FDA definitions and key attributes of master protocols.

Trial Type	Definitions	Key attributes
Master protocol	“…[A] protocol designed with multiple substudies, which may have different objectives and [involve] coordinated efforts to evaluate one or more investigational drugs in one or more disease subtypes within the overall trial structure.”	•Multiple sub studies under one overarching protocol •Interventional (not diagnostic)
Basket trial	“A master protocol designed to test a single investigational drug or drug combination in different populations defined by disease stage, histology, number of prior therapies, genetic or other biomarkers, or demographic characteristics.”	•Single intervention studied •Multiple disease populations
Umbrella trial	“A master protocol designed to evaluate multiple investigational drugs administered as single drugs or as drug combinations in a single disease population.”	•Multiple interventions studied •Single disease population
Platform trial	“[A trial designed to] study multiple targeted therapies in the context of a single disease in a perpetual manner, with therapies allowed to enter or leave the platform on the basis of a decision algorithm”.	•Multiple interventions studied •Perpetual trial •Capacity to add and drop trial arms

The definitions taken from the FDA Draft Guidance on Efficient Clinical Trial Designs and Woodcock et al. (2017) were used to identify and adapt key attributes of master protocols [1,2].