Enarodustat

The 2-oxoglutarate (2OG)/Fe(II)-dependent γ-butyrobetaine hydroxylase (BBOX) catalyzes the final step in l-carnitine biosynthesis, i.e., stereoselective C-3 oxidation of γ-butyrobetaine (GBB). BBOX inhibition is a validated clinical strategy to modulate l-carnitine levels and to enhance cardiovascular efficiency. Reported BBOX inhibitors, including the clinically used cardioprotective agent Mildronate, manifest moderate inhibitory activity in vitro, limited selectivity, and/or unfavorable physicochemical properties, indicating a need for improved BBOX inhibitors. We report that the clinically used hypoxia-inducible factor-α prolyl residue hydroxylase (PHD) inhibitors Desidustat, Enarodustat, and Vadadustat efficiently inhibit isolated recombinant BBOX, suggesting that BBOX inhibition by clinically used PHD inhibitors should be considered as a possible off-target effect. Structure-activity relationship studies on the Desidustat scaffold enabled development of potent BBOX inhibitors that manifest high levels of selectivity for BBOX inhibition over representative human 2OG oxygenases, including PHD2. The Desidustat derivatives will help to enable investigations into the biological roles of l-carnitine and the therapeutic potential of BBOX inhibition.

Enarodustat is a hypoxia-inducible factor-prolyl hydroxylase inhibitor. We evaluated the pharmacokinetics, pharmacodynamics, and safety profile of domestic enarodustat (SAL-0951) and analyzed the influence of ethnic factors.

In this phase I study, healthy Chinese participants received single and multiple oral doses (1, 5, and 15 mg) of SAL-0951 while in a fasted state. We monitored the pharmacokinetics, pharmacodynamics, and safety characteristics and analyzed the impact of ethnicity on pharmacokinetic characteristics.

In total, 33 healthy Chinese participants were enrolled; the mean age was 31.2 ± a standard deviation of 5.5 years. After single doses of 1, 5, and 15 mg were administered under fasted conditions, SAL-0951 was rapidly absorbed. Mean maximum plasma concentration and area under the plasma concentration-time curve from time 0 to the last quantifiable concentration increased dose proportionately from 0.14 to 2.54 μg/mL and from 0.63 to 9.50 h × μg/mL, respectively. The elimination half-life was 6.13, 6.32, and 6.74 h, respectively, in these three groups, and the mean value of apparent clearance ranged from 1.64 to 1.89 L/h. SAL-0951 was excreted mostly as the parent compound. It reached a stable concentration after 5 days of multiple-dose administration. We observed no drug accumulation or time-dependent pharmacokinetic characteristics and no significant difference in pharmacokinetic characteristics between Chinese and Japanese participants.

SAL-0951 was safe and well tolerated in healthy Chinese participants and had a linear pharmacokinetic profile. We found no ethnic differences in the pharmacokinetic characteristics of the drug between Chinese and Japanese populations.

Registered at Chinadrugtrials.org.cn, registration number CTR2020245.