We felt that demonstration of feasibility and safety was a necessary first step prior to embarking on a larger pivotal clinical trial, given that the clinical utility of an NT-proBNP–guided strategy to neurohormonal therapy initiation and titration has never been tested, and there are both patient and clinician concerns about additional noncancer medications, tolerability, and safety in a population with active cancer receiving chemotherapy. Here, NPPB is linked to cancer.