A randomised trial from the Mass General Brigham Heart and Vascular Institute showed that a single 1000mg intravenous dose of ferric derisomaltose improved peak oxygen uptake and other functional measures at 12 weeks in patients with heart failure with preserved ejection fraction (HFpEF) and iron deficiency.
The IRON-MET HFpEF trial randomised 65 symptomatic participants (median age 68 years; 72% women; iron deficiency present in >50% of HFpEF overall) 2:1 to the iron infusion or placebo. Oral iron has previously proved ineffective in other heart-failure phenotypes, attributed to poor absorption. Results were presented at the 2026 American Heart Association Scientific Sessions and published simultaneously in Circulation.
At 12 weeks, peak VO₂ rose by approximately 10% in the iron arm and was unchanged with placebo. Pre-specified secondary endpoints (six-minute walk distance, VO₂ at the anaerobic threshold, and NYHA class) also improved, as did markers of iron bioavailability. Patient-reported health scores did not differ significantly. No serious adverse events were linked to the infusion.
Lead author Dr Gregory D. Lewis stated that the study was the first to comprehensively evaluate exercise responses to iron repletion in this population and that ferric derisomaltose improved multiple capacity measures. Dr Rajeev Malhotra noted that the peak VO₂ increment is clinically meaningful; longer-term outcome studies in more diverse cohorts are now required.
Source: Mass General Brigham
