During a late-breaking clinical-trials session at the Heart Failure Congress 2013 of the ESC Heart Failure Association, the results of the RELAX-AHF analysis (Relaxin for the Treatment of Acute Heart Failure)  were presented.
The analysis showed that serelaxin is probably more effective in reducing shortness of breath during the first 24 hours in heart-failure patients with preserved ejection fractions (HF-PEF) than in patients with reduced ejection fractions (HF-REF), with the greatest effect in patients with left ventricular ejection fractions >50%.
Meanwhile, treatment with serelaxin  resulted in similar improvements in area-under-the-curve (AUC) from baseline to day 5 on a dyspnea visual analog scale (VAS) in both patient groups.

In RELAX-AHF, 26% of the study cohort had preserved ejection fractions, defined as >50%. Patients with HF-PEF were older, had slightly higher systolic blood pressure, were more likely to be female, arrived a little later at hospital, were more likely to have hypertension, and were more likely to be treated with an aldosterone antagonist.
There was no improvement in clinical outcomes in patients with HF-PEF or HF-REF. Cardiovascular death and all-cause mortality at day 180 were both significantly reduced by 37% overall, without a significant interaction based on ejection-fraction status. There was also no significant interaction with regard to changes in biomarkers, such as cardiac cystatin C or N-terminal prohormone of brain natriuretic peptide (NT-proBNP).

The RELAX-AHF study included 1160 patients with acute heart failure and systolic blood pressure >125 mm Hg randomized to serelaxin (via a 48-hour intravenous infusion within 16 hours of presentation) or placebo. Serelaxin resulted in a 19% improvement in AUC from baseline to day 5 on a dyspnea VAS, as well as a moderate—but not statistically significant—improvement in dyspnea at 24 hours measured using a Likert scale.

Source:
Abstract 260 Heart Failure Congress 2013, Heart Failure Association of the European Society of Cardiology. Effects of serelaxin on blood pressure: results from the RELAX-AHF Trial
M. Metra, J.R. Teerlink, G. Cotter, B.A. Davison, G.M. Felker, G. Filippatos, B.H. Greenberg, P. Ponikowski, A.A. Voors, T. Severin (Brescia, IT; San Francisco, Durham, NC and San Diego (CA), US; Athens, GR; Wroclaw, PL; Groningen, NL; Basel, CH)