Relaxin: A Novel Agent for the Treatment of Acute Heart Failure

Acute heart failure (AHF) is defined by a constellation of signs and symptoms that manifest when new or decompensated ventricular dysfunction is triggered by an acute precipitant such as excessive preload, afterload, or myocardial ischemia. Despite being one of the most frequent causes of hospitalization and cardiovascular mortality, little to no progress has been made over the last few decades to advance the treatment of AHF. Current mainstays of pharmacotherapy for AHF including diuretics, vasodilators, and inotropes can improve symptoms; however, no currently approved agent has been shown to provide lasting outcome benefit for patients with AHF. First discovered in pregnant women where it is known to help with growth of the cervix and assist with the maternal cardiovascular and renovascular responses to pregnancy, relaxin is an endogenous neurohormone that has novel vasoactive properties. In particular, relaxin is a potent vasodilator with a number of pleiotropic effects that may affect cardiac remodeling, making relaxin an attractive compound for use in the management of AHF. Indeed, in two randomized controlled trials, a single 48-hour infusion of relaxin relieved symptoms of AHF with no evidence of major adverse effects. A signal of mortality benefit at 180 days was noted in both trials, prompting a third trial of relaxin powered for 180-day mortality that is currently under way. The pharmacology that underscores the potential benefit of relaxin is discussed and insight is provided into future clinical application of this novel drug should it prove to be the first therapy capable of reducing mortality in AHF.