Patiromer for the Management of Hyperkalemia in Subjects Receiving RAASi Medications for the Treatment of Heart Failure (DIAMOND)

Prospective Phase 3b multinational, multicenter, double-blind, placebo-controlled, randomized withdrawal, parallel group study that includes screening and up to 12 weeks Run-in Phase (all subjects will have patiromer initiated and RAASi medications, including mineralocorticoid receptor antagonist (MRA) optimized) and a randomized withdrawal Blinded Treatment Phase. The study population includes subjects with heart failure (HF) with reduced ejection fraction (HFrEF) who are hyperkalemic (serum potassium \[K+\] \> 5.0 mEq/L) while receiving treatment with renin angiotensin aldosterone system inhibitor (RAASi) medications or who are normokalemic (serum K+ 4.0 - 5.0 mEq/L) but have a history of hyperkalemia prior to screening with subsequent reduction or discontinuation of a RAASi medication. Each subject's participation includes a Run-in Phase (maximum 12 weeks) followed by the Treatment Phase (variable per subject). Study duration for individual subjects will vary, depending on their individual enrollment date. Subjects who prematurely discontinue patiromer/placebo will remain in the study for the collection of clinical events data and will receive usual care.