Randomized Double Blind Placebo Controlled PK/PD Study On the Effects of a Single Intravenous Dose of the Anti-Hepcidin Spiegelmer Nox-H94 On Serum Iron During Experimental Human Endotoxemia

Anemia of chronic disease (ACD) is generally attributed to increased hepcidin production. The first-in-class hepcidin antagonist NOX-H94, a PEGylated anti-hepcidin L-RNA oligonucleotide, is in development for targeted treatment of ACD. We investigated whether NOX-H94 prevents the inflammation-induced serum iron decrease during experimental human endotoxemia. Effects on the innate immune response were studied as secondary endpoints.

The study protocol (ClinicalTrials.gov identifier NCT01522794) was approved by the local ethics committee of the Radboud University Nijmegen Medical Centre and was conducted in accordance with the Declaration of Helsinki (2000) of the World Medical Association.

This randomized, double-blind, placebo-controlled trial was carried out in 24 healthy young men. At T=0 hours (h), 2 ng/kg E. coli endotoxin was administered intravenously (i.v.), followed by 1.2 mg/kg NOX-H94 or placebo i.v. at T=0.5h. Blood was drawn serially for 24h and at day 3, 8 and 15 after endotoxin administration for measurements of inflammatory parameters, cytokines, NOX-H94 pharmacokinetics, total hepcidin-25 (free and NOX-H94-bound), and iron parameters. The difference of serum iron change from baseline at T=9h was defined as primary endpoint. Data are expressed as mean±SD.

Endotoxin administration led to flu-like symptoms peaking at T=1.5h, irrespective of the treatment group. Body temperature rose by 1.9±0.5 °C in both groups. Peak CRP at T=24h was also similar in NOX-H94 and placebo treated groups (34.3±18.0 vs. 36.8±8.7 mg/L) as was the rise in leucocytes at T=6 h (12.1±2.2 vs. 12.1±2.3 ×10⁹/L). Plasma levels of TNF-α, IL-6, IL-10, and IL-1RA peaked markedly and similarly in both treatment groups.

NOX-H94 was well tolerated. Plasma concentrations peaked at 0.7±0.4 h after the start of administration, after which they declined according to a two-compartment model, with rapid initial elimination followed by a slower elimination phase with a plasma half-life of 22.5 ± 4.28h. Hepcidin-25 rose to a peak of 23.0±5.2 nM at T=5.5±0.05 h in control subjects and normalized at about T=24 h. In the NOX-H94 treated group, total hepcidin-25 concentrations, which represent the sum of free hepcidin-25 and hepcidin-25 bound to NOX-H94, rose to 559±112 nM at T=9.5±1.5 h and normalized slowly until day 15.

The observed serum iron concentrations are shown in the table. In the placebo group, serum iron increased from baseline to a peak at T=3h, returned close to baseline at T=6h and decreased under the baseline concentration at T=9h reaching its lowest point at T=12h. In the NOX-H94 group, serum iron concentrations rose until T=6h and then slowly declined until T=24h. From 6 to 12 h post LPS, the serum iron concentrations in NOX-H94 treated subjects were significantly higher than in placebo treated subjects (P<0.0001, ANCOVA). At T=24 h and 48 h, serum iron was lower in NOX-H94 treated subjects than in placebo controls.

Experimental human endotoxemia induced a robust inflammatory response with hepcidin release and a subsequent decrease in serum iron. Treatment with NOX-H94 had no effect on innate immunity, but effectively prevented the inflammation-induced drop in serum iron concentrations. These findings demonstrate the clinical potential of the anti-hepcidin drug NOX-H94 for further development to treat patients with ACD.

van Eijk:NOXXON Pharma AG: Research Funding. Swinkels:NOXXON Pharma AG: Research Funding. Schwoebel:NOXXON Pharma AG: Employment. Fliegert:NOXXON Pharma AG: Employment. Summo:NOXXON Pharma AG: Employment. Stéphanie:NOXXON Pharma AG: Employment. Riecke:NOXXON Pharma AG: Employment. Pikkers:NOXXON Pharma AG: Research Funding.