Oral Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitor Roxadustat (FG-4592) for Treatment of Anemia in Chronic Kidney Disease: A Placebo-Controlled Study of Pharmacokinetic and Pharmacodynamic Profiles in Hemodialysis Patients.

Roxadustat (FG-4592), an oral hypoxia-inducible factor prolyl hydroxylase inhibitor that stimulates erythropoiesis, was evaluated in a phase 1b study in patients with end-stage renal disease with anemia on hemodialysis. Seventeen patients, on epoetin-alfa maintenance therapy with stable hemoglobin levels ≥10 g/dL, had epoetin-alfa discontinued on day 3 and were enrolled in this double-blind placebo-controlled study. Two cohorts were randomized 3:1 (roxadustat: placebo). Patients received single doses of roxadustat (1 or 2 mg/kg) or placebo 1 hour after hemodialysis on day 1 and 2 hours before dialysis on day 8. Maximum plasma concentration and area under the plasma concentration-time curve for patients receiving roxadustat were slightly more than dose proportional and elimination half-life ranged from 14.7 to 19.4 hours. Roxadustat was highly protein bound (99%) in plasma, and dialysis contributed a small fraction of the total clearance: only 4.56% and 3.04% of roxadustat recovered from the 1 and 2 mg/kg dose groups, respectively. Roxadustat induced transient elevations of endogenous erythropoietin that peaked between 7 and 14 hours after dosing and returned to baseline by 48 hours after dosing. Peak median endogenous erythropoietin levels were 96 mIU/mL and 268 mIU/mL for the 1- and 2-mg/kg doses, respectively, within physiologic range of endogenous erythropoietin responses to hypoxia at high altitude or after blood loss. No serious adverse events were reported, and there were no treatment- or dose-related trends in adverse event incidence.

A Single-Dose, Open-Label, Randomized, Two-Way Crossover Study in Healthy Japanese Participants to Evaluate the Bioequivalence and the Food Effect on the Pharmacokinetics of Daprodustat.

Daprodustat is a prolyl hydroxylase inhibitor that stimulates erythropoiesis in a manner similar to the natural response to hypoxia, whereby inhibition of hypoxia inducible factor (HIF) prolyl-4-hydroxylases by daprodustat ultimately results in increased levels of HIF-responsive genes. Daprodustat is under development as an emerging new class of agents for the treatment of anemia associated with chronic kidney disease (CKD). This was a single-center, single-dose, open-label, randomized, 2-way crossover study in healthy Japanese male participants consisting of 2 parts. The primary objective was to evaluate the bioequivalence (BE) between daprodustat tablet strengths (part 1) and to evaluate the food effect on the pharmacokinetics (PK) of daprodustat (part 2). A total of 64 healthy Japanese male participants were enrolled; 52 participants were included in part 1 and 12 in part 2. BE was demonstrated between the daprodustat 2-mg tablet and the daprodustat 4-mg tablet. A standard CKD meal did not have a large effect on the PK parameters of daprodustat after a single oral dose of daprodustat 4 mg. Administration of single oral doses of daprodustat 4 mg was generally well tolerated in the healthy Japanese participants, and no new safety signals were identified without regard to food.

A sensitive assay for ZYAN1 in human whole blood and urine utilizing positive LC-MS/MS electrospray ionization.

AIM: A sensitive LC-MS/MS method was developed and validated for estimation of ZYAN1 in human blood/urine. METHODS: An analog internal standard IOX2 along with ZYAN1 was quantified using selective reaction monitoring in positive mode. The chromatographic separation was performed by gradient elution with C18 analytical column (3 µm, 50 mm × 2.0 mm) with 4-min run time using an acidified mobile phase consisting of ammonium formate and acetonitrile. Protein precipitation enabled extraction of analytes from diluted blood/urine. RESULTS: Calibration curve of ZYAN1 was linear (2-5000 ng/ml). The recovery of ZYAN1 and IOX2 was between 87 and 104%. Interday and intraday accuracy and precision was found well within the acceptance criteria. CONCLUSION: The validated assay was applied for clinical pharmacokinetics of ZYAN1 in healthy volunteers.

Overcoming bioanalytical challenges associated with the separation and quantitation of GSK1278863, a HIF-prolyl hydroxylase inhibitor, and its 14 stereoisomeric metabolites.

GSK1278863 is an investigative drug under investigation for treatment of anemia associated with chronic kidney disease. Its metabolism is primarily metabolized by P450 enzymes where 19 unique metabolic species have been identified. These include multiple products of mono-, di-, and tri-oxygenation. Initially, two separate and complex ultra high performance liquid chromatography (UHPLC) reverse phase methodologies were developed, validated and applied to measure parent and various predominant and circulating metabolites in numerous clinical studies. However, 5 of the 6 oxidative metabolites may exist in different stereoisomeric forms, resulting in 14 separate species; therefore a chiral methodology was required to determine which stereoisomeric forms circulated in human. A variety of conventional approaches were explored, where in the end a supercritical fluid chromatography (SFC) method was required to separate this complex mixture of 14 stereoisomeric metabolites; data from these experiments provided important information on which species circulate in human. The details of these methodologies will be discussed herein.