AHU-377 hemicalcium salt is a potent NEP inhibitor with an IC50 of 5 nM. AHU-377 is a component of the heart failure medicine LCZ696. AHU377 is a prodrug of LBQ657, which is an inhibitor of the zinc metallopeptidase neprilysin. Neprilysin degrades a variety of vasoactive peptides such as atrial and brain natriuretic peptide, bradykinin, adrenomedullin, and endothelin-1. Inhibition of neprilysin leads to an increased level of these peptides and, thus, antihypertensive effects. Formulations containing AHU377 in combination with the angiotensin II receptor antagonist valsartan are used to treat hypertension and heart failure.