Effects of oral iron and calcium supplement on the pharmacokinetics and pharmacodynamics of molidustat: an oral HIF–PH inhibitor for the treatment of renal anaemia

The present studies assessed the drug–drug interaction of molidustat, a hypoxia-inducible factor prolyl hydroxylase inhibitor, with iron and calcium supplements, which are common medications in patients with anaemia due to chronic kidney disease (CKD). Forty-two healthy men received molidustat alone (fasted or fed) or combined with oral iron(II) or calcium(II), given immediately before or between 4 h before and 1 h after molidustat in three randomized, open-label, crossover studies (12–15 participants per study). Molidustat AUC and Cmax were assessed as the main pharmacokinetic parameters, and endogenous erythropoietin (EPO) was measured to evaluate pharmacodynamics. Depending on prandial state, concomitant intake of iron(II) reduced molidustat AUC and Cmax by 50–75% and 46–84%, respectively, and EPO AUC(0-24) and Cmax by 31–44% and 36–48%, respectively. The influence of iron(II) declined with increasing the time interval to the intake of molidustat, with reductions in molidustat AUC and Cmax of 9% and 10%, respectively, when iron(II) intake occurred 4 h before molidustat. Accordingly, effects on endogenous EPO were less pronounced with increased time separation between oral iron(II) and molidustat intake. Calcium(II) reduced molidustat AUC and Cmax by 15% and 47%, respectively, without influence on EPO response. All treatments were well tolerated. In contrast to concomitant oral intake of calcium, the effect of oral iron supplements on molidustat pharmacokinetics and pharmacodynamics should be considered, and the two agents should be administered with an appropriate time separation.