Disposition and metabolism of the G protein-coupled receptor 40 agonist TAK-875 (fasiglifam) in rats, dogs, and humans.

The absorption, distribution, metabolism, and excretion of fasiglifam were investigated in rats, dogs, and humans. The absolute oral bioavailability of fasiglifam was high in all species (>76.0%). After oral administration of [14C]fasiglifam, the administered radioactivity was quantitatively recovered and the major route of excretion of radioactivity was via feces in all species. Fasiglifam was a major component in the plasma and feces in all species. Its oxidative metabolite (M-I) was observed as a minor metabolite in rat and human plasma (<10% of plasma radioactivity). In human plasma, hydroxylated fasiglifam (T-1676427), the glucuronide of fasiglifam (fasiglifam-G), and the glucuronide of M-I were detected as additional minor metabolites (<2% of plasma radioactivity). None of these metabolites were specific to humans. Fasiglifam-G was the major component in the rat and dog bile. In vitro cytochrome P450 (CYP) and uridine diphosphate glucuronosyltransferase (UGT) reaction phenotyping indicated that oxidation (to form M-I and T-1676427) and glucuronidation of fasiglifam are mainly mediated by CYP3A4/5 and UGT1A3, respectively. Fasiglifam and fasiglifam-G are substrates of BCRP and Mrp2/MRP2, respectively. Glucuronidation of fasiglifam-G was found to be the predominant elimination pathway of fasiglifam in all species tested, including humans.

Pre-clinical Characterization of Absorption, Distribution, Metabolism and Excretion Properties of TAK-063.

TAK-063 is currently being developed to treat schizophrenia. In this study, we investigated the absorption, distribution, metabolism and excretion (ADME) properties of TAK-063 using several paradigms. Following oral administration of TAK-063 at 0.3 mg/kg, bioavailability of TAK-063 was 27.4% in rats and 49.5% in dogs with elimination half-lives of 3.1 hr in rats and 3.7 hr in dogs. TAK-063 is a highly permeable compound without P-glycoprotein (P-gp) or breast cancer resistance protein substrate liability and can be readily absorbed into systemic circulation via the intestine. TAK-063 can also cross the blood-brain barrier. TAK-063 was metabolized mainly by CYP2C8 and CYP3A4/5, while incubation with human liver microsomes produced the major human metabolite, M-I as well as several unknown minor metabolites. Metabolism of TAK-063 to M-I occurs through hydroxylation of the mono-substituted pyrazole moiety. In vitro, TAK-063 was observed to inhibit CYP2C8, CYP2C19 and P-gp with IC50 values of 8.4, 12 and 7.13 µM, respectively. TAK-063 was primarily excreted in the faeces in rats and dogs with M-I as a predominant component. The pre-clinical data from these ADME studies demonstrate a favourable pharmacokinetic profile for TAK-063 with good brain distribution supporting the feasibility of targeting central nervous system regions involved in schizophrenia pathophysiology. TAK-063 has recently been investigated in a phase 2 clinical trial (NCT02477020).

Long-Term Stability of Cryopreserved Human Hepatocytes: Evaluation of Phase I and II Drug-Metabolizing Enzyme Activities and CYP3A4/5 Induction for More than a Decade.

We evaluated the long-term stability of hepatocytes stored in the vapor phase of liquid nitrogen for their viability, cytochrome P450 (CYP) 1A2 activity, CYP3A4/5 activity, uridine diphosphate-glucuronosyl transferase (UGT) activity, sulfotransferase (SULT) activity, and CYP3A4/5 induction during 14 years of preservation. No substantial degradation of viability, CYP1A2 activity, UGT activity, or CYP3A4/5 induction was observed. CYP3A4/5 activity showed a slight decrease after 7 years of storage, and SULT activity gradually decreased during storage, although substantial activities remained even after 14 years. These results indicate that cryopreserved human hepatocytes can be stored stably for more than a decade with little or no change in viability, activity of drug-metabolizing enzymes, or CYP3A4/5 induction, and can be widely applicable to qualitative research in drug metabolism.

Metabolic fate of sipoglitazar, a novel oral PPAR agonist with activities for PPAR-γ, -α and -δ, in rats and monkeys and comparison with humans in vitro.

Sipoglitazar is a novel anti-diabetic agent with triple agonistic activities on the human peroxisome proliferator-activated receptors, hPPAR-γ, -α, and -δ. The bioavailability for sipoglitazar was 95.0% and 72.6% in rats and monkeys respectively and sipoglitazar is hardly subject to first pass metabolism in either species. Following oral administration of [¹4C]sipoglitazar to rats, sipoglitazar and its metabolites were distributed to the rat tissues with relatively high concentrations in the liver and also to the target tissue, the adipose tissue. The major component was sipoglitazar in the plasma of rats and monkeys. In rats, sipoglitazar was mainly excreted into the feces via biliary excretion as sipoglitazar-G, while the major component was M-I-G in the urine and M-I in the feces of monkeys. In hepatocytes, the metabolism was not extensively advanced in rats and the main metabolites were M-I and sipoglitazar-G in humans, similar to the metabolic profile in monkeys. There was no metabolite specific for humans in vitro. In conclusion, the formation of M-I, M-I-G and sipoglitazar-G is considered to be crucial and sipoglitazar is presumed to be cleared primarily by oxidation and glucuronidation in humans, when examined in vivo and in vitro.

An unusual metabolic pathway of sipoglitazar, a novel antidiabetic agent: cytochrome P450-catalyzed oxidation of sipoglitazar acyl glucuronide.

Animal pharmacokinetic studies of sipoglitazar, a novel antidiabetic agent, showed that the deethylated metabolite (M-I) and the glucuronide conjugate of sipoglitazar (sipoglitazar-G) appeared to be the key metabolites in the elimination process. M-I was also measured as the main metabolite in the plasma of humans administered sipoglitazar. In vitro metabolic studies were performed to investigate the metabolic pathways from sipoglitazar to M-I in humans. The metabolic profile with human hepatocytes and hepatic microsomes indicated that M-I was not formed directly from sipoglitazar and that sipoglitazar-G was involved in the metabolism from sipoglitazar to M-I. Further studies of the metabolism of sipoglitazar-G revealed that the properties of the glucuronide conjugate and its metabolism are as follows: high-performance liquid chromatography, liquid chromatography-tandem mass spectrometry, and NMR analyses showed that sipoglitazar-G was composed of two glucuronides, sipoglitazar-G1, a ß-1-O-acyl glucuronide, and sipoglitazar-G2, an α-2-O-acyl glucuronide. The stability study of these glucuronides suggested that sipoglitazar-G1 could be converted to sipoglitazar-G2 and sipoglitazar, but sipoglitazar-G2 could not be converted to sipoglitazar-G1. The oxidative metabolic study of sipoglitazar-G1 and -G2 with human hepatic microsomes and cytochrome P450-expressing microsomes revealed that M-I was formed only from sipoglitazar-G1, not from sipoglitazar-G2, and that CYP2C8 was mainly involved in this process. From these results, it is shown that the metabolic pathway from sipoglitazar to M-I is an unusual one, in which sipoglitazar is initially metabolized to sipoglitazar-G1 by UDP-glucuronosyltransferase and then sipoglitazar-G1 is metabolized to M-I by O-dealkylation by CYP2C8 and deconjugation. Sipoglitazar-G2 is sequentially formed by the migration of the ß-site of sipoglitazar-G1.

Classification of clinical subtypes, patient survival, kidney prognosis, and relapse in patients with MPO-ANCA-associated vasculitis: a single-center experience.

Myeloperoxidase-type antineutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitis may manifest various organ symptoms. Treatment allows recovery from early, but severe, organ involvement. However, the relationship between the initial organ involvement and the eventual clinical course has not been studied in this disease. Therefore, the current study evaluated 30 patients who were hospitalized and then categorized into ten clinical subtypes based on organ involvement. The relationship of these subtypes to development of clinical features, patient survival, kidney prognosis, and relapse were evaluated over an average observation period of 4.3 years. During this study, the most common clinical features were lung and kidney involvement. Twenty-one patients already manifested clinical features around the time of admission and did not commonly present new symptoms as long as they were receiving the treatment for vasculitis. In contrast, as far as pulmonary involvement type at the initial time was concerned and in those not being treated for vasculitis, 7 of the 12 patients progressed to pulmo-renal involvement and 5 of them went onto renal failure. Progression to renal failure also occurred frequently in patients with pulmo-renal type manifesting at the initial time. Thirteen patients died, including three patients due to vasculitis of systemic type, seven due to infections, and three due to malignancy. Death due to vasculitis occurred in the early phase of treatment and was associated with either pulmonary hemorrhage or gastrointestinal bleeding. Infectious death occurred throughout the entire course of treatment, mostly in patients with pulmo-renal or pulmonary type, and tended to be associated with opportunistic organisms. Death with malignancy was observed after several years of treatment. Regarding renal prognosis, ten patients underwent hemodialysis. At initiation of hemodialysis, nine patients had pulmo-renal type and only one had renal type. A relapse was observed in ten patients, mainly in patients with pulmo-renal or pulmonary type, and it occurred after about 2.7 years, even with treatment. Such relapses manifested in a similar manner to their initial clinical subtypes. These results suggest that pulmo-renal type as well as pulmonary type have a high chance to progress to renal failure or systemic type, and they were fairly commonly associated with vasculitic or infectious death. Therefore, classification of clinical subtypes at the initial time and on admission is meaningful to some extent for predicting patient survival, kidney prognosis, and relapse, in addition to indicating the appropriate treatment regimen.