CRD-4730 is a calcium/calmodulin-dependent protein kinase II (CaMKII) inhibitor. The CALIBRATE-HF trial is a Phase 2, global, multi-center, randomized, double-blind, parallel-group, placebo-controlled trial. The trial will evaluate the efficacy, safety, and tolerability of CRD-4730 in addition to guideline directed medical therapy in participants with heart failure with reduced ejection fraction (HFrEF). Participants will be randomized to 1 of 4 study groups and receive investigational study drug or placebo twice daily (BID) for 24 weeks of treatment.