Abstract The PREPARE-NS program will develop and establish the psychometric properties of a core set of clinical outcome assessments (COAs) for nephrotic syndrome, with primary focus on fluid overload (FO). During the UG3 phase, a diverse team of experts and stakeholders will be convened, in cooperation with the FDA, to confirm conditions, measures and anchors and design the studies necessary to identify a rigorous and patient- centered FO endpoint definition and measure set. The UH3 will focus on testing and implementing the core set of COAs identified in the UG3 phase. The research conducted in the UH3 phase will allow us to refine the FO COAs. The final activities will be focused on making the final core set of COAs widely available to the public for use in trials. For both phases, we will work in close consultation with the project stakeholder engagement and clinician expert panels, drawing from the perspectives of patients, clinicians, regulators, payers, and drug developers. Tapping these resources, and relying on our team's wide-ranging clinical, COA development, and psychometric expertise, we will generate a core set of highly-relevant COAs that will advance patient-focused drug development in nephrotic syndrome.