Pharmacokinetics, safety, and tolerability of the novel tetrameric gadolinium-based MRI contrast agent gadoquatrane in healthy Chinese and Japanese men: Two randomized dose-escalation studies including concentration-QTc modeling.

PURPOSE: To investigate the pharmacokinetics, safety, and tolerability of the novel tetrameric high-relaxivity gadolinium-based contrast agent gadoquatrane in Japanese (Study 1) and Chinese men (Study 2). PARTICIPANTS AND METHODS: In two similarly designed single-center, randomized, single-blind, placebo-controlled, consecutive-cohort dose-escalation studies, healthy volunteers were randomly assigned to intravenous administration of gadoquatrane (0.01-0.1 mmol gadolinium/kg body weight) or placebo. Study procedures included blood sampling and collection of urine for pharmacokinetic analyses and safety assessments. RESULTS: Twenty-five healthy Japanese men (mean age ± standard deviation: 26±5.9 years) and 23 healthy Chinese men (31±7.6 years old) were evaluated. In both studies, the pharmacokinetic profile of gadoquatrane was characterized by rapid distribution of the drug into the extracellular space and fast renal elimination. Postdose gadolinium concentrations rapidly declined with a geometric mean effective half-life of 1.3-1.4 h. The exposure increased approximately dose-proportionally with dose. The body weight-normalized volume of distribution was constant across dose levels (0.21-0.24 L/kg). Total recovery of gadolinium in urine amounted to 82-95 % (Study 1) and 96-99 % (Study 2) of the dose administered. Only a few mild, transient adverse events were reported, none of which gave rise to any safety concerns. Exploratory drug concentration-QTc modeling indicated no risk of a clinically relevant QT/QTc prolongation at the anticipated diagnostic dose. CONCLUSION: Gadoquatrane was safe and well tolerated at all doses tested. The pharmacokinetic profile was essentially the same as that of other extracellular macrocyclic gadolinium-based contrast agents and was consequentially also similar for Japanese and Chinese participants.

Absorption, distribution, metabolism and excretion of molidustat in healthy participants.

The absorption, distribution, metabolism and excretion of molidustat were investigated in healthy male participants. In study 1, a mass balance study, radiolabelled molidustat 25 mg (3.57 MBq) was administered as an oral solution (n = 4). Following rapid absorption, molidustat-related radioactivity was predominantly distributed in plasma rather than in red blood cells. The total recovery of the administered radioactivity was 97.0%, which was mainly excreted renally (90.7%). Metabolite M-1, produced by N-glucuronidation, was the dominant component in plasma (80.2% of the area under the concentration-time curve for total radioactivity) and was primarily excreted via urine (~85% of dose). Only minor amounts of unchanged molidustat were excreted in urine (~4%) and faeces (~6%). Study 2 investigated the absolute bioavailability and pharmacodynamics of molidustat (part 1, n = 12; part 2, n = 16). Orally administered molidustat immediate release tablets had an absolute bioavailability of 59%. Following intravenous administration (1, 5 and 25 mg), total body clearance of molidustat was 28.7-34.5 L/h and volume of distribution at steady state was 39.3-50.0 L. All doses of molidustat transiently elevated endogenous erythropoietin levels, irrespective of the route of administration. Molidustat was considered safe and well tolerated at the administered doses.

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.

PURPOSE: 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). METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Pharmacokinetics and Safety After a Single Dose of Imarikiren in Subjects with Renal or Hepatic Impairment.

BACKGROUND AND OBJECTIVE: Imarikiren hydrochloride (TAK-272; SCO-272) is a novel direct renin inhibitor. The objective of this study was to determine the effects of renal impairment (RI) or hepatic impairment (HI) on the pharmacokinetics and safety of imarikiren. METHODS: This phase I, open-label, parallel-group comparative study evaluated the pharmacokinetics and safety of a single 40 mg oral dose of imarikiren in RI [mild, moderate, severe, or end-stage renal disease (ESRD), and on hemodialysis] or HI (mild or moderate) subjects compared with subjects with normal renal or hepatic function. RESULTS: Following administration of a single 40 mg oral imarikiren dose, the geometric mean imarikiren area under the plasma concentration-time curve from time zero to infinity (AUC∞) and maximum observed plasma concentration (Cmax) in subjects with mild, moderate, and severe RI (including non-hemodialysis and ESRD), and hemodialysis subjects compared with normal renal function subjects were approximately 0.5-, 1.2-, 2.7-, and 1.8-fold, respectively, for AUC∞; and approximately 0.6-, 0.8-, 2.1-, and 1.4-fold, respectively, for Cmax. The mean fraction of excretion of imarikiren in dialysate was ~ 3% during the 4 h dialysis period. The geometric mean imarikiren AUC∞ and Cmax in mild and moderate HI subjects compared with normal hepatic function subjects were approximately 1.0- and 1.4-fold, respectively, for AUC∞, and approximately 0.9- and 1.3-fold, respectively, for Cmax. No deaths or serious adverse events were observed; all adverse events were mild or moderate in intensity. CONCLUSIONS: RI and HI are associated with limited changes in imarikiren pharmacokinetics. Imarikiren was safe and well-tolerated, regardless of the severity of RI or HI. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02367872.

Pharmacokinetics, Pharmacodynamics and Safety of a Single Dose of Imarikiren, a Novel Renin Inhibitor, in Healthy Male Subjects.

Imarikiren hydrochloride (TAK-272/SCO-272) is a novel direct renin inhibitor with potential indications for cardiovascular and renal diseases. This phase I study evaluated the pharmacokinetics, pharmacodynamics and safety of a single oral administration of imarikiren in healthy Japanese male subjects. The Dose-Ascending part (double-blind, placebo-controlled, parallel-group design; n = 60) comprised six steps from 5 to 200 mg (n = 8 for imarikiren and n = 2 for placebo per step). The Food Effect part (n = 12) was an open-label, 2 × 2 crossover design with a dose of 50 mg to evaluate the effect of food on the pharmacokinetics and safety of imarikiren. There was a generally linear relationship between dose and area under the plasma concentration-time curve (0 to infinity) or maximum plasma concentration of imarikiren. Food had no clinically significant effect on the exposure of imarikiren. Inhibition of plasma renin activity was rapid and lasted up to 24 hr at all doses. Plasma active renin concentration increased, reaching a maximum at approximately 6 hr, in a nearly dose-dependent manner. Across both study parts, the number of subjects with treatment-emergent adverse events ranged from 0 to 3 per group with no dependency on dose. All treatment-emergent adverse events except two were mild in intensity; there were no serious adverse events or deaths. Single oral administration of imarikiren from 5 to 200 mg was safe and well tolerated. These findings suggest that further clinical development of a once-daily imarikiren regimen is warranted.

A Randomized, Single-Center, Double-Blind, Placebo-Controlled Multiple-Dose Phase 1 Study to Evaluate the Safety, Pharmacokinetics, and Pharmacodynamics of Imarikiren in Healthy Adult Nonelderly and Elderly Male Subjects.

Imarikiren hydrochloride (TAK-272/ SCO-272) is a novel direct renin inhibitor. This randomized, double-blind, phase I study evaluated the safety and pharmacokinetics/pharmacodynamics of multiple oral administrations of imarikiren in healthy nonelderly (aged 20-45 years) and elderly (aged 65-85 years) Japanese male subjects. Subjects were randomized within 1 of 3 cohorts to receive imarikiren or placebo: Cohort 1 (imarikiren 80 mg; nonelderly), Cohort 2 (imarikiren 160 mg; nonelderly), or Cohort 3 (imarikiren 80 mg; elderly). Imarikiren or placebo was administered orally, once daily, for 7 days. Accumulation of imarikiren did not occur during the 7-day treatment period. Area under the plasma-concentration time curve and maximum plasma concentration of imarikiren were higher in elderly than in nonelderly subjects (52% and 39% higher, respectively). Inhibition of plasma renin activity was observed for 7 days and was maintained for at least 71 hours after the last imarikiren administration at the 80-mg (nonelderly and elderly) and 160-mg (nonelderly) doses. Plasma active renin concentration increased in nonelderly and elderly subjects; peak concentrations were higher on day 7 than on day 1. Increase from baseline in plasma active renin concentration was smaller in elderly than in nonelderly subjects during the 7-day treatment period and until 71 hours after last imarikiren administration. Treatment-emergent adverse events were reported in 33.3% (elderly) and 22.2% (nonelderly) of imarikiren subjects. Multiple oral administrations of imarikiren for 7 days were safe and well tolerated with no drug accumulation and strong and sustained suppression of plasma renin activity.

Pharmacokinetics, Safety, and Tolerability of Vortioxetine Following Single- and Multiple-Dose Administration in Healthy Japanese Adults.

Three phase 1 randomized single-center studies assessed the pharmacokinetics, safety, and tolerability of vortioxetine after single- and multiple-dose administration in healthy Japanese adults. Study 1 assessed the pharmacokinetics of vortioxetine after administration of single rising doses to men and multiple doses to men and women; study 2 evaluated vortioxetine pharmacokinetics in elderly adults; and study 3 assessed food effects on vortioxetine pharmacokinetics in healthy men. The primary end points included pharmacokinetic parameters of vortioxetine and incidence of adverse events (AEs). Across all studies, 130 participants were randomized and 128 participants completed the studies. Vortioxetine was absorbed and eliminated from plasma slowly, and exposure to vortioxetine increased in an almost dose-proportional manner. No clinically significant differences in the pharmacokinetics of vortioxetine or its metabolites were observed between the sexes in young and elderly adults. Study 3 demonstrated that vortioxetine and its metabolites had similar pharmacokinetics when administered in the fasted and fed states. Importantly, vortioxetine was safe and tolerated, with incidence of AEs comparable to that of placebo. No deaths or serious AEs leading to trial discontinuation were observed. Overall, vortioxetine pharmacokinetics, safety, and tolerability in Japanese adults were comparable to reports in non-Japanese populations.

A multicenter, phase III evaluation of the efficacy and safety of a new fixed-dose pioglitazone/glimepiride combination tablet in Japanese patients with type 2 diabetes.

BACKGROUND: This study aimed to determine the efficacy and safety of pioglitazone/glimepiride as a fixed-dose combination (FDC) in Japanese patients with type 2 diabetes. SUBJECTS AND METHODS: In this multicenter, phase III, open-label evaluation, eligible patients had to have a glycosylated hemoglobin (HbA(1c)) level of ≥7.4% and <10.4% halfway through a 4-week run-in period while being treated with glimepiride 1 or 3 mg once daily plus diet and exercise. At baseline, patients were assigned to 8 weeks of treatment with pioglitazone/glimepiride (15 mg/1 mg) FDC once daily (group A; n=31) or pioglitazone/glimepiride (30 mg/3 mg) FDC once daily (group B; n=31) according to their glimepiride dose during run-in. RESULTS: Pioglitazone/glimepiride significantly reduced the mean HbA(1c) level from baseline (primary end point) by 0.59±0.556% in group A (P<0.0001) and by 0.55±0.637% in group B (P<0.0001). Corresponding reductions in the mean fasting blood glucose level were 12.5±21.67 mg/dL (P=0.0032) and 29.1±35.38 mg/dL (P<0.0001). Significant alterations from baseline to week 8 in either one or both treatment groups were also noted for the following parameters: 1,5-anhydroglucitol, glycoalbumin, triglycerides, high-density lipoprotein cholesterol, and free fatty acid levels. Five patients in group A (16.1%) had five treatment-related adverse events, and 10 patients in group B (32.3%) had 13 such events; all events were mild. CONCLUSIONS: Pioglitazone/glimepiride as a FDC (30 mg/3 mg and 15 mg/1 mg once daily) significantly improved glycemic control and lipid profiles and was well tolerated in Japanese patients with type 2 diabetes.

Influence of glutathione S-transferase A1 polymorphism on the pharmacokinetics of busulfan.

BACKGROUND: High-dose oral busulfan is used for myeloablative chemotherapy before hematopoietic stem-cell transplantation. Fatal adverse effects or relapse may occur with excess or insufficient busulfan exposure. Glutathione S-transferase (GST) A1, whose genetic polymorphism in its promoter region has been reported, is responsible for busulfan metabolism. We investigated the polymorphism of GSTA1 on busulfan pharmacokinetics. METHODS: Blood samples (6 or 7 points) were taken from patients receiving high-dose oral busulfan (approximately 1 mg/kg every 6 h) on Doses 1 and 5. Pharmacokinetic parameters were calculated from plasma busulfan concentration. RESULTS: Twelve patients were enrolled in this study. Nine patients were genotyped as wildtype (GSTA1*A/*A), and 3 as heterozygous variants (GSTA1*A/*B). At Dose 5, the heterozygous group had significantly lower elimination constant (0.176+/-0.038 vs. 0.315+/-0.021 h-1; P=0.008) and clearance corrected by bioavailability (0.118+/-0.013 vs. 0.196+/-0.011 l/h/kg; P=0.004), and significantly higher mean plasma busulfan concentration (1344+/-158 vs. 854+/-44 ng/ml; P=0.001) than the wildtype. CONCLUSIONS: This is the first report on the significant influence of GSTA1 polymorphism on busulfan elimination. This may account for the large inter-individual variance in busulfan pharmacokinetics, and with more information confirming our study, busulfan high-dose therapy may be optimized by GSTA1 genotyping in advance.

Genetic analysis of glutathione S-transferase A1 and T1 polymorphisms in a Japanese population.

Novel allelic variants have been found in the glutathione S-transferase (GST) A1 and T1 genes. The former GSTA1*B allele is associated with low expression and the latter GSTT1*B allele lacks GSTT1 activity. The information on frequencies of both variants is poorly documented in the Japanese population. In this study we determined the frequencies of allelic variants of GSTA1 and GSTT1 in a Japanese population using PCR-restriction fragment length polymorphism and allele-specific PCR. The frequencies of GSTA1*B, GSTT1*0 and GSTT1*B alleles in the subjects were 16.0%, 71.1% and 0%, respectively. This is the first report on the frequencies of allelic variants of GSTA1 and GST-1 in a Japanese population.

A new method for determination of buformin in plasma and urine by ion-paired reversed-phase HPLC with ultraviolet detection.

Buformin is a widely used as an antidiabetic agent but its renal excretion is still controversial. A new HPLC method with ultraviolet (UV) detection for the determination of buformin in plasma and urine has been developed. After protein precipitation or dilution, buformin and internal standard phenformin were resolved on an octadecyl silica column and detected by UV detection at 233 nm. Intra- and inter-day coefficients of variation were <9%. The limit of quantification was around 0.05 micro g/ml for plasma and 2.5 micro g/ml for urine.