Akifumi Kogame

Pharmacokinetic and Pharmacodynamic Modeling of Hedgehog Inhibitor TAK-441 for the Inhibition of Gli1 messenger RNA Expression and Antitumor Efficacy in Xenografted Tumor Model Mice

6-Ethyl-N-[1-(hydroxyacetyl)piperidin-4-yl]-1-methyl-4-oxo-5-(2-oxo-2-phenylethyl)-3-(2,2,2-trifluoroethoxy)-4,5-dihydro-1H-pyrrolo[3,2-c]pyridine-2-carboxamide (TAK-441) is a potent, selective hedgehog signaling pathway inhibitor that binds to Smo and is being developed for the treatment of cancer. The objectives of these studies were to explore the possibility of establishing of a link between the pharmacokinetics of TAK-441 and the responses of Gli1 mRNA in tumor-associated stromal or skin cells and the antitumor effect of hedgehog inhibition. To this end, we built pharmacokinetic and pharmacodynamic models that describe the relationship of the concentrations of TAK-441 plasma to the responses of Gli1 mRNA in the tumor (target) and skin (surrogate) and to tumor growth inhibition in mice bearing xenografts of human pancreatic tumors (PAN-04). The responses of Gli1 mRNA and tumor growth were described by an indirect response model and an exponential tumor growth model, respectively. The IC50 values for Gli1 mRNA inhibition in the tumor and skin by TAK-441 were estimated to be 0.0457 and 0.113 μg/ml, respectively. The IC90 value for tumor growth inhibition was estimated to be 0.68 μg/ml. These results suggest that a >83% inhibition of Gli1 mRNA expression in the skin or a >94% inhibition of Gli1 mRNA expression in the tumor would be required to sufficiently inhibit (>90%) hedgehog-related tumor growth in the xenografted model mice. We conclude that Gli1 mRNA expression in the tumor and skin could be a useful biomarker for predicting the antitumor effect of hedgehog inhibitors

Disposition and metabolism of TAK-438 (vonoprazan fumarate), a novel potassium-competitive acid blocker, in rats and dogs

Abstract 1. Following oral administration of [14C]TAK-438, the radioactivity was rapidly absorbed in rats and dogs. The apparent absorption of the radioactivity was high in both species. 2. After oral administration of [14C]TAK-438 to rats, the radioactivity in most tissues reached the maximum at 1-hour post-dose. By 168-hour post-dose, the concentrations of the radioactivity were at very low levels in nearly all the tissues. In addition, TAK-438F was the major component in the stomach, whereas TAK-438F was the minor component in the plasma and other tissues. High accumulation of TAK-438F in the stomach was observed after oral and intravenous administration. 3. TAK-438F was a minor component in the plasma and excreta in both species. Its oxidative metabolite (M-I) and the glucuronide of a secondary metabolite formed by non-oxidative metabolism of M-I (M-II-G) were the major components in the rat and dog plasma, respectively. The glucuronide of M-I (M-I-G) and M-II-G were the major components in the rat bile and dog urine, respectively, and most components in feces were other unidentified metabolites. 4. The administered radioactive dose was almost completely recovered. The major route of excretion of the drug-derived radioactivity was via the feces in rats and urine in dogs.

Influence of the pharmacokinetic profile on the plasma glucose lowering effect of the PPARγ agonist pioglitazone in Wistar fatty rats

Although the mechanism of action for peroxisome proliferator‐activated receptor gamma (PPARγ) agonists has been extensively explored, the impact of the pharmacokinetic (PK) profile on the pharmacodynamic (PD) effects of PPARγ agonists has not been elucidated in detail. The importance of the PK profile of PPARγ agonist was evaluated for its PD effect based on population PK/PD analysis. Pioglitazone hydrochloride, the PPARγ agonist, was administered orally to Wistar fatty rats once a day (q.d.) or once every other day (q.2d.) as double the amount for the q.d. treatment. The plasma glucose lowering effect was selected as a surrogate PD effect for an anti‐diabetic effect. The model fitting was conducted using the non‐linear mixed effect modeling (NONMEM) method. The indirect response model described well the plasma glucose concentration–time profile. The q.d. treatment showed a stronger impact on the plasma glucose lowering effect than did the q.2d. treatment. The results of PK/PD modeling suggested that the sensitivity (i.e. EC50) between each group was comparable. On the other hand, the time above the effective concentration in the q.d. treatment group was longer than that in the q.2d. treatment group. The simulation of various dose regimens suggested that the much longer exposure duration within the effective level showed a stronger plasma glucose lowering effect, even with identical exposure to pioglitazone in the plasma. The PK/PD analysis clarified that the PK profile affected the pharmacological response and that continuous exposure at an appropriate effective level would be efficient for the anti‐diabetic effect of the PPARγ agonist.

Development, validation and application of the liquid chromatography tandem mass spectrometry method for simultaneous quantification of azilsartan medoxomil (TAK-491), azilsartan (TAK-536), and its 2 metabolites in human plasma

Azilsartan medoxomil potassium salt (TAK-491) is an orally administered angiotensin II type 1 receptor blocker for the treatment of hypertension and is an ester-based prodrug that is rapidly hydrolyzed to the pharmacologically active moiety, azilsartan (TAK-536), during absorption. TAK-536 is biotransformed to the 2 metabolites M-I by decarboxylation and M-II by dealkylation. In this study, we developed and validated a LC/MS/MS method which can simultaneously determine 4 analytes, TAK-491, TAK-536, M-I and M-II. The bioanalytical method can be outlined as follows: two structural analogues are used as the internal standards. The analytes and the IS are extracted from human plasma using solid phase extraction. After evaporating, the residue is reconstituted and injected into a LC/MS/MS system with an ESI probe and analyzed in the positive ion mode. Separation is performed through a conventional reversed-phase column with a mobile phase of water/acetonitrile/acetic acid (40:60:0.05, v/v/v) mixture at a flow rate of 0.2mL/min. The total run time is 8.5min. The calibration range is 1-2500ng/mL in human plasma for all the analytes. Instability issues of the prodrug, TAK-491, were overcome and all the validation results met the acceptance criteria in accordance with the regulatory guideline/guidance. As a result of the clinical study, the human PK profiles of TAK-536, M-I and M-II were successfully obtained and also it was confirmed that TAK-491 was below the LLOQ (1ng/mL) in the human plasma samples.

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

Abstract 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.

Investigation of disposition for TAK-448, a synthetic peptide of kisspeptin analog, in rats and dogs using the radiolabeled TAK-448 suitable for pharmacokinetic study

Abstract Disposition of 2-(N-acetyl-d-tyrosyl-trans-4-hydroxy-l-prolyl-l-asparaginyl-l-threonyl-l-phenylalanyl) hydrazinocarbonyl-L-leucyl-Nω-methyl-l-arginyl-l-tryptophanamide monoacetate (TAK-448, RVT-602), a synthetic kisspeptin analog, was investigated after parenteral dosing of radiolabeled TAK-448 ([d-Tyr-14C]TAK-448) to rats and dogs, and it was confirmed if the radiolabeling position at d-Tyr was eligible for assessment of in vivo disposition. Dosed radioactivity was rapidly and well absorbed after subcutaneous administration and an appreciable amount of unchanged TAK-448 (TAK-448F) and a hydrolyzed metabolite, M-I, were detected in the plasma of rats and dogs. After intravenous administration of [d-Tyr-14C]TAK-448 to rats, the radioactivity widely distributed to tissues with relatively higher concentrations in kidney and urinary bladder. The radioactivity was decreased rapidly from the tissues. After subcutaneous administration of [d-Tyr-14C]TAK-448 to rats and dogs, the dosed radioactivity was almost completely recovered by 48 and 72 h in rats and dogs, respectively, and most of the radioactivity was excreted in urine after extensive metabolism in the two species. These results suggest that TAK-448 has an acceptable pharmacokinetic profile for clinical evaluation and development, and demonstrate that the synthesized [D-Tyr-14C]TAK-448 used in this study represents a favorable labeling position to evaluate disposition properties of this compound.

Usefulness of pharmacokinetic/efficacy analysis of an investigational kisspeptin analog, TAK-448, in quantitatively evaluating anti-tumor growth effect in the rat VCaP androgen-sensitive prostate cancer model

ABSTRACT TAK‐448 is a kisspeptin analog with improved in vivo potency. In our previous studies in the rat JDCaP prostate cancer model, TAK‐448 showed more rapid and profound reductions in plasma testosterone (T) and prostate‐specific antigen (PSA, a biomarker of prostate tumor growth) levels than the gonadotropin releasing hormone (GnRH) analog leuprolide (TAP‐144); however, its effects on tumor volume and subsequent tumor recurrence have not been elucidated fully. To overcome these challenges, we established the rat VCaP subcutaneous xenograft model replicating both the androgen‐sensitive and castration‐resistant phases of prostate cancer, and we performed pharmacokinetic/efficacy (PK/E) correlation analyses to compare the overall anti‐tumor growth effects of TAK‐448 to those of TAP‐144. Our approach demonstrated TAK‐448 had greater anti‐tumor growth potential, including in the castration‐resistant phase, than TAP‐144 in this rat VCaP model. TAK‐448 treatment was associated with a reduction in intra‐tumoral dihydrotestosterone levels, which might explain its superior anti‐tumor activity. Thus, our PK/E analysis was effective at providing new insights into the therapeutic efficacy of TAK‐448 as a novel ADT agent in our rat VCaP model.

Abstract 5041: Translational pharmacokinetic-pharmacodynamic xenograft model for TAK-931, a small molecule cell division cycle 7 (CDC7) kinase inhibitor

TAK-931 is a small molecule inhibitor of the cell division cycle 7 (CDC7) kinase. As a serine/threonine kinase that contributes to DNA replication and the DNA damage response, CDC7 is hypothesized to be a promising cancer drug target. CDC7 inhibition with TAK-931 has demonstrated antiproliferative activity with cancer cell lines and tumor growth inhibition (TGI) in murine ectopic xenograft models. Herein, the analysis of multiple models to characterize pharmacokinetic (PK) and pharmacodynamic (PD) relationships with xenograft TGI is described. TAK-931 treatment-induced TGI was dose schedule-independent and could be described using plasma drug concentrations or tumor PD inhibition. However, the efficacious doses were at least 10-fold higher for the PK-TGI relationship than for the PD-TGI relationship. This discrepancy was used to select a dynamic PK-PD-TGI modeling approach to project the minimal efficacious dose (MED) and minimal biological active dose (MBAD) for TAK-931 due to the large differences in time-concentration profiles predicted for humans versus mice. The Phase I human trial is on-going and will be used to verify the dynamic PK-PD-driven modeling approach for the CDC7 inhibitor. Citation Format: Charles Locuson, Mayank Patel, Akihiro Ohashi, Kenichi Iwai, Tadahiro Nambu, Toshiyuki Takeuchi, Akifumi Kogame, Douglas Bowman, Stephen Tirrell, Huifeng Niu, Cindy Xia. Translational pharmacokinetic-pharmacodynamic xenograft model for TAK-931, a small molecule cell division cycle 7 (CDC7) kinase inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5041. doi:10.1158/1538-7445.AM2017-5041

Mo1146 Localization of a Novel Potassium Competitive Acid Blocker, Vonoprazan, in the Rat Gastric Mucosa: A Radiographic Study

G A A b st ra ct s at least one year of follow-up within THIN who also lacked chronic conditions associated with use of long-term acid suppression. Cases of fracture were defined by the first Read code for incident fracture at any site and the control pool consisted of individuals without a diagnosis of fracture at the time when the corresponding case had his or her first fracture. Using incidence density sampling, cases were matched with up to 5 control subjects by age (within 1 year), sex, THIN practice, and start of follow-up in THIN (within 1 year). PPI exposure was defined as 180 or more cumulative doses of PPIs. We additionally examined the PPI-fracture relationship at varying levels of PPI exposure. As potential confounders, we extracted information related to age, sex, body mass index, and use of other medications. The primary outcome was calculated using conditional logistic regression as the odds of PPI exposure in cases compared to controls. Because the epidemiology of fracture varies by age, we stratified analyses using a cut-off of 18 years old or more. RESULTS: 508,740 children age 4 to 17 years old and 207,181 young adults age 18 to 29 years old within the THIN database were included in the study. We identified 124,799 cases of incident fracture and 605,643 matched controls. In young adults but not children, PPIs were a risk factor for fracture in both unadjusted and adjusted models. The adjusted odds ratio for the risk of fracture associated with PPI exposure was 1.13 (95% CI 0.92 to 1.39) among children and 1.39 (95% CI 1.26 to 1.53) among young adults. In young adults but not children, we observed a dose-response effect with increased total exposure to PPIs (p for trend <.001). CONCLUSIONS: PPI use was associated with non-osteoporotic fracture in young adults but not children. Young adults who use PPIs should be cautioned regarding potentially increased risk for fracture, even if they lack traditional fracture risk factors.

Evaluation of low background liquid scintillation counter for non-clinical ADME studies

1. The performance of low background (BG) liquid scintillation counter (LSC) was evaluated for practical purposes of non-clinical drug absorption, distribution, metabolism and excretion (ADME) studies. The measurement conditions for the radioactivity for low BG LSC were investigated and metabolite profiling in rat plasma after single oral administration of 14C-labeled compounds was performed. Metabolite profiling was also conducted using conventional LSC and accelerator mass spectrometer (AMS), and the performances of these measuring instruments were compared. 2. The established measurement conditions showed good linearity of the calibration curve over the concentration range from 3 to 300 dpm/vial. Metabolite profiling using low BG LSC for the plasma samples diluted to 5–55 times was comparable to that using conventional LSC for the undiluted plasma samples. Meanwhile, metabolite profiling using AMS for the plasma samples diluted to 250–2000 times was comparable to that using conventional LSC. 3. These results suggest that the application of low BG LSC is one of the useful tools for non-clinical ADME studies and that it is possible to select conventional LSC, low BG LSC or AMS for radioactivity measurement by considering the specific radioactivity of the compounds and the predicted concentrations of radioactivity in biological samples in ADME studies.