Serelaxin is a recombinant form of human relaxin-2, a vasodilator hormone that contributes
to cardiovascular and renal adaptations during pregnancy. Previous studies have suggested
that treatment with serelaxin may result in relief of symptoms and in better outcomes
in patients with acute heart failure.In this multicenter, double-blind, placebo-controlled,
event-driven trial, we enrolled patients who were hospitalized for acute heart failure
and had dyspnea, vascular congestion on chest radiography, increased plasma concentrations
of natriuretic peptides, mild-to-moderate renal insufficiency, and a systolic blood
pressure of at least 125 mm Hg, and we randomly assigned them within 16 hours after
presentation to receive either a 48-hour intravenous infusion of serelaxin (30 μg
per kilogram of body weight per day) or placebo, in addition to standard care. The
two primary end points were death from cardiovascular causes at 180 days and worsening
heart failure at 5 days.A total of 6545 patients were included in the intention-to-treat
analysis. At day 180, death from cardiovascular causes had occurred in 285 of the
3274 patients (8.7%) in the serelaxin group and in 290 of the 3271 patients (8.9%)
in the placebo group (hazard ratio, 0.98; 95% confidence interval [CI], 0.83 to 1.15;
P = 0.77). At day 5, worsening heart failure had occurred in 227 patients (6.9%) in
the serelaxin group and in 252 (7.7%) in the placebo group (hazard ratio, 0.89; 95%
CI, 0.75 to 1.07; P = 0.19). There were no significant differences between the groups
in the incidence of death from any cause at 180 days, the incidence of death from
cardiovascular causes or rehospitalization for heart failure or renal failure at 180
days, or the length of the index hospital stay. The incidence of adverse events was
similar in the two groups.In this trial involving patients who were hospitalized for
acute heart failure, an infusion of serelaxin did not result in a lower incidence
of death from cardiovascular causes at 180 days or worsening heart failure at 5 days
than placebo. (Funded by Novartis Pharma; RELAX-AHF-2 ClinicalTrials.gov number, NCT01870778.).
