Serelaxin and acute heart failure.

Attempts at developing novel therapeutic agents for acute heart failure (AHF) over the past two decades have been marked by disappointment. Relaxin is a human peptide hormone believed to mediate many adaptive haemodynamic changes that occur during pregnancy. Because these effects may be useful for treating AHF, a recombinant version of human relaxin-2, serelaxin, has been developed as a novel therapeutic agent. Studies have confirmed serelaxin's haemodynamic effects of decreasing pulmonary and systemic resistance and increasing renal blood flow. A 1161-patient, placebo-controlled Phase III trial, RELAX-AHF, demonstrated significant improvement in symptoms, reduced worsening of heart failure, decreased hospital length of stay and increased 180-day survival after index hospitalisation. Additional Phase III trials (RELAX-AHF-2; RELAX-AHF-ASIA) are underway to further evaluate the efficacy of serelaxin in patients with AHF. This article will review the physiological function, mechanism of action, clinical trial results and future directions of serelaxin in the treatment of AHF.