DIAMOND trial: Patiromer lowers risk of severe hyperkalaemia

Heart failure with reduced ejection fraction (HFrEF) patients taking renin-angiotensin-aldosterone system inhibitors (RAASi) had significantly lower serum potassium levels when adding the potassium-binding agent patiromer to their regimen compared with placebo.

Prof. Javed Butler (University of Mississippi, MS, USA) presented the initial results from the randomised, phase 3 DIAMOND trial (NCT03888066) [1]. DIAMOND was designed to determine whether patiromer can favourably impact potassium control in patients with HFrEF with hyperkalaemia (>5.5 mEq/L) or a history of hyperkalaemia, and consequently optimise RAASi use to prevent cardiovascular events [2]. Patients with HFrEF and hyperkalaemia were randomised to patiromer (n=439) or placebo (n=439) after an initial run-in phase during which all participants received patiromer.

Due to COVID-19, the trial's original primary endpoint—the time to cardiovascular death or first hospitalisation for a cardiovascular event—had to be changed. The supply chain for patiromer was uncertain, and there were concerns about the ability to closely monitor patients, Prof. Butler explained. The researchers decided to shift the primary endpoint to a laboratory value, namely the treatment's effect on serum potassium levels.

The study met this revised primary endpoint; patiromer led to a significant mean reduction in potassium levels by study end versus placebo (-0.13 mEq/L in the patiromer group vs -0.03 mEq/L in the control group; P<0.001). The incidence of hyperkalaemia was 13.9% in the patiromer group compared with 19.4% in the control group (P=0.006), leading to a hyperkalaemia-related outcome win ratio of 1.53 (P<0.001). Importantly, patiromer allowed 85% of participants to be optimised on guideline-directed medical doses of RAASi, with a use-score win ratio of 1.25 (P=0.048). Furthermore, as a secondary endpoint, 21.6% of participants on patiromer needed to reduce mineralocorticoids as compared with 26.7% of those assigned placebo (HR 0.74; 95% CI 0.57–0.97; P=0.030).In conclusion, the data from DIAMOND indicate that patiromer was able to maintain lower serum potassium levels and was associated with a lower incidence of severe hyperkalaemia compared with placebo. It has yet to be determined whether this intervention results in a reduced incidence of cardiovascular events.

1. 
   
   1. Butler J et al. Patiromer For The Management Of Hyperkalemia In Subjects Receiving Renin-angiotensin-aldosterone System Inhibitor Medications For Heart Failure With Reduced Ejection Fraction: Results From The DIAMOND Trial. Abstract 406–14, ACC 2022, 2–4 April, Washington DC, USA.
   
   
   2. Butler J, et al. Eur J Heart Fail. 2022;24(1):230–238.

 

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Posted on 15 June, 2022