This is a clinical safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) study of a single ascending dose (SAD) and a multiple ascending dose (MAD) of the oral direct factor Xa inhibitor edoxaban in healthy males. The placebo-controlled, single-blind, randomized, 2-part study consists of a SAD arm with 85 subjects (10, 30, 60, 90, 120, 150 mg) and a MAD arm with 36 subjects (90 mg daily, 60 mg twice daily, 120 mg daily). Effects of food and formulation (tablet vs solution) are assessed in a crossover substudy. In the SAD, doses are well tolerated up to 150 mg. Exposure is proportional to dose. PK profiles are consistent across dose with rapid absorption, biphasic elimination, and terminal elimination half-life of 5.8 to 10.7 hours. In the MAD, mean accumulation after daily dosing is 1.10 to 1.13 and consistent with elimination half-life of 8.75 to 10.4 hours. Intrasubject variability ranges from 12% to 17% for area under the curve. In general, plasma edoxaban concentrations are linearly correlated with coagulation parameters. Edoxaban is safe and well tolerated with no dose-dependent increases in adverse events. It is concluded that single and multiple doses of edoxaban are safe and well tolerated up to 150 mg with predictable PK and PD profiles.

ABSTRACT:This study determined the mass balance and pharmacokinetics of edoxaban in humans after oral administration of [ 14 C]edoxaban.After oral administration of 60 mg (as active moiety) of [ 14 C]edoxaban to six healthy male subjects, serial blood/plasma and urinary and fecal samples were collected for up to 168 h postdose. All samples were analyzed for total radioactivity by liquid scintillation counting and for concentrations of edoxaban and four metabolites in plasma, urine, and fecal samples by either high-performance liquid chromatography/tandem mass spectrometry method using multiple reaction modes, or a liquid chromatography radiometric method. The mean recovery of radioactivity was >97% of the administered radioactive dose, with 62.2% eliminated in feces and 35.4% in urine. Unchanged edoxaban accounted for the majority of radioactivity, with 49.1 and 23.8% of the dose as parent observed in feces and urine, respectively. Unchanged edoxaban was the most abundant species in plasma, with a mean area under the curve (AUC) 0؊ؕ of 1596 ng ⅐ h/ml. The next most abundant species was metabolite M4, with a mean AUC 0؊ؕ 147 ng ⅐ h/ml. The mass balance of edoxaban was well described, with unchanged edoxaban as the most abundant component of total radioactivity. Edoxaban is eliminated through multiple pathways, but each accounts for only a small amount of overall elimination.

Mucopolysaccharidoses (MPS) are caused by deficiency of lysosomal enzyme activities needed to degrade glycosaminoglycans (GAGs), which are long unbranched polysaccharides consisting of repeating disaccharides. GAGs include: chondroitin sulfate (CS), dermatan sulfate (DS), heparan sulfate (HS), keratan sulfate (KS), and hyaluronan. Their catabolism may be blocked singly or in combination depending on the specific enzyme deficiency. There are 11 known enzyme deficiencies, resulting in seven distinct forms of MPS with a collective incidence of higher than 1 in 25,000 live births. Accumulation of undegraded metabolites in lysosomes gives rise to distinct clinical syndromes. Generally, the clinical conditions progress if untreated, leading to developmental delay, systemic skeletal deformities, and early death. MPS disorders are potentially treatable with enzyme replacement therapy or hematopoietic stem cell transplantation. For maximum benefit of available therapies, early detection and intervention are critical. We recently developed a novel high-throughput multiplex method to assay DS, HS, and KS simultaneously in blood samples by using high performance liquid chromatography/tandem mass spectrometry for MPS. The overall performance metrics of HS and DS values on MPS I, II, and VII patients vs. healthy controls at newborns were as follows using a given set of cut-off values: sensitivity, 100%; specificity, 98.5–99.4%; positive predictive value, 54.5–75%; false positive rate, 0.62–1.54%; and false negative rate, 0%. These findings show that the combined measurements of these three GAGs are sensitive and specific for detecting all types of MPS with acceptable false negative/positive rates. In addition, this method will also be used for monitoring therapeutic efficacy. We review the history of GAG assay and application to diagnosis for MPS.

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