Randomisation
REFINE will randomise participants centrally through an interactive web-based system using minimisation (with a random element) with stratification by a small number of important stratification factors. For stage I, patients will be randomly assigned in the ratio 1:1 to Arm A (SOC interval) and Arm B (extended interval). The precise allocation ratio for stage II will be determined after completion of stage I, but it is anticipated that more patients will be allocated to the added arms than to the existing stage I arms, to achieve approximately equal total allocation between all arms.