Christian LeungJae H. ChangNing LiuZhengyin Yan...
11页
查看更多>>摘要：The utilization of in vitro data to predict drug pharmacokinetics (PK) in vivo has been a consistent practice in early drug discovery for decades. However, its success is hampered by mispredictions attributed to uncharacterized biological phenomena/experimental artifacts. Predicted drug clearance (CL) from experimental data (i.e., intrinsic clearance: CL_int; fraction unbound in plasma: f_u,p) is often systematically underpredicted using the well-stirred model (WSM). The objective of this study was to evaluate using empirical scalars in the WSM to correct for CL mispredictions. Drugs (N = 28) were used to generate numerical scalars on CL_int (α) and f_u,p (β) to minimize the absolute average fold error (AAFE) for CL predictions. These scalars were validated using an additional dataset (N = 28 drugs) and applied to a non-redundant AstraZeneca (AZ) dataset available in the literature (N = 117 drugs) for a total of 173 compounds. CL predictions using the WSM were improved for most compounds using an α value of 3.66 (~64% < 2-fold) compared with no scaling (~46% < 2-fold). Similarly, using a β value of 0.55 or combination of α and β scalars (values of 1.74 and 0.66, respectively) resulted in a similar improvement in predictions (~64% < 2-fold and ~65% < 2-fold, respectively). For highly bound compounds (fu,p ≤ 0.01), AAFE was substantially reduced across all scaling methods. Using the β scalar alone or a combination of α and β appeared optimal and produced larger magnitude corrections for highly bound compounds. Some drugs are still dis-proportionally mispredicted; however, the improvements in prediction error and simplicity of applying these scalars suggest its utility for early-stage CL predictions.
Tatiana KoudriakovaKevin J. CoeJ. William HigginsPerry Leung...
13页
查看更多>>摘要：[4-(4-Methyl-2-(4-(trifluoromethyl)phenyl)thiazole-5-yl)pyrimi-dine-2-amine] (JNJ-2482272), under investigation as an anti-inflammatory agent, was orally administered to rats once daily at 60 mg/kg for 6 consecutive days. Despite high plasma exposure after single administration (C_max of 7.1 μM), JNJ-2482272 had plasma concentrations beneath the lower limit of quantification (3 ng/ml) after 6 consecutive days of dosing. To determine if JNJ-2482272 is an autoinducer in rats, plated rat hepatocytes were treated with JNJ-2482272 for 2 days. The major hydroxyl-ated metabolites of JNJ-2482272 were isolated and characterized by mass spectrometry and NMR analyses. Compared with the vehicle-treated cells, a concentration-dependent increase was observed in the formation of phase I- and II-mediated metabolites coinciding with greater expression of cytochrome P450s (P450s) and UDP-glucuronosyltransferases (UGTs) in rat hepatocytes. CYP1A1, CYP1A2, CYP1B1, and UGT1A6 transcripts were predominantly induced, suggesting that JNJ-2482272 is an activator of the aryl hydrocarbon receptor (AhR). In a human AhR reporter assay, JNJ-2482272 demonstrated potent AhR activation with an EC_50 value of 0.768 nM, a potency more comparable to the strong AhR activator and toxin 2,3,7, 8-tetrachloro-dibenzodioxin than to weaker AhR activators 3-methylcholanthrene, β-naphthoflavone, and omeprazole. In plated human hepatocytes, JNJ-2482272 induced CYP1A1 gene expression with an EC_50 of 20.4 nM and increased CYP1A activity >50-fold from basal levels. In human recombinant P450s, JNJ-2482272 was exclusively metabolized by the CYP1 family of enzymes and most rapidly by CYP1A1. The summation of these in vitro findings bridges the in vivo conclusion that JNJ-2482272 is a strong autoinducer in rats and potentially in humans through potent AhR activation.
Cliff ChenXue-Qing ChenSagnik ChatterjeeDavid J. Shuster...
10页
查看更多>>摘要：Farnesoid X receptor (FXR) is a nuclear receptor known to markedly alter expression of major transporters and enzymes in the liver. However, its effects toward organic anion transporting polypeptides (OATP) 1B1 and 1B3 remain poorly characterized. Therefore, the present study was aimed at determining the effects of chenodeoxycholic acid (CDCA), a naturally occurring FXR agonist, on OATP1B expression in cynomolgus monkeys. Multiple administrations of 50 and 100 mg/kg of CDCA were first shown to significantly repress mRNA expression of SLCO1B1/3 approximately 60% to 80% in monkey livers. It also suppressed cytochrome P450 (CYP)7A1-mRNA and induced OSTa/b-mRNA, which are well known targets of FXR and determinants of bile acid homeostasis. CDCA concomitantly decreased OATP1B protein abundance by approximately 60% in monkey liver. In contrast, multiple doses of 15 mg/kg rifampin (RIF), a pregnane X receptor agonist, had no effect on hepatic OATP1B protein, although it induced the intestinal P-glycoprotein and MR2 proteins by ~2-fold. Moreover, multiple doses of CDCA resulted in a steady ~2- to 10-fold increase of the OATP1B biomarkers copropor-phyrins (CPs) in the plasma samples collected prior to each CDCA dose. Additionally, 3.4- to 11.2-fold increases of CPI and CPIII areas under the curve were observed after multiple administrations compared with the single dose and vehicle administration dosing groups. Taken together, these data suggest that CDCA represses the expression of OATP1B1 and OATP1B3 in monkeys. Further investigation of OATP1B downregulation by FXR in humans is warranted, as such downregulation effects may be involved in bile acid homeostasis and potential drug interactions in man.
查看更多>>摘要：NN1177 is a glucagon/glucagon-like peptide 1 receptor coagonist investigated for chronic weight management and treatment of nonalcoholic steatohepatitis. Here, we show concentration-dependent downregulation of cytochrome P450 (P450) enzymes using freshly isolated human hepatocytes treated with this linear 29-amino acid peptide. Notably, reductions in CYP3A4 mRNA expression (57.2%-71.7%) and activity (18.5%-51.5%) were observed with a clinically relevant concentration of 100 nM NN1177. CYP1A2 and CYP2B6 were also affected but to a lesser extent. Physiologic-based pharmacokinetic modeling simulated effects on CYP3A4 and CYP1A2 probe substrates (midazolam and caffeine, respectively) and revealed potential safety concerns related to drug-drug interactions (DDIs). To investigate the clinical relevance of observed in vitro P450 down-regulation, a phase 1 clinical cocktail study was initiated to assess the DDI potential. The study enrolled 45 study participants (body mass index 23.0-29.9 kg/m~2) to receive a DDI cocktail (midazolam, caffeine, omeprazole, dextromethorphan, and S-warfarin/vitamin K) alone and following steady-state NN1177 exposure. The analysis of pharmacokinetic profiles for the cocktail drugs showed no significant effect from the coadministration of NN1177 on AUC_0-inf for midazolam or S-warfarin. Omeprazole, caffeine, and dextromethorphan generally displayed decreases in AUC_0-inf and C_max following NN1177 coadministration. Thus, the in vitro observations were not reflected in the clinic. These findings highlight remaining challenges associated with standard in vitro systems used to predict DDIs for peptide-based drugs as well as the complexity of DDI trial design for these modalities. Overall, there is an urgent need for better preclinical models to assess potential drug-drug interaction risks associated with therapeutic peptides during drug development.
Thomas J. DiProsperoLauren G. BrownTrevor D. FachkoMatthew R. Lockett...
8页
查看更多>>摘要：The cellular microenvironment plays an important role in liver zo-nation, the spatial distribution of metabolic tasks among hepato-cytes lining the sinusoid. Standard tissue culture practices provide an excess of oxygen and a lack of signaling molecules typically found in the liver. We hypothesized that incorporating physiologically relevant environments would promote postdifferentiation patterning of hepatocytes and result in zonal-like characteristics. To test this hypothesis, we evaluated the transcriptional regulation and activity of drug-metabolizing enzymes in HepaRG cells exposed to three different oxygen tensions, in the presence or absence of Wnt/b-catenin signaling. The drug-metabolizing activity of cells exposed to representative periportal (11% O_2) or perivenous (5% O_2) oxygen tensions were significantly less than cells exposed to ambient oxygen. A comparison of cytochrome P450 (P450) 1A2, 2D6, and 3A4 activity at periportal and perivenous oxygen tensions showed significant increases at the lower oxygen tension. The activation of the Wnt/β-catenin pathway only modestly impacted P450 activity at perivenous oxygen tension, despite a significant increase in P450 expression under this condition. Our results suggest oxygen tension is the major contributor to zonal patterning in HepaRG cells, with the Wnt/β-catenin signaling pathway playing a lesser albeit important role. Our datasets also highlight the importance of including activity-based assays, as transcript data alone do not provide an accurate picture of metabolic competence.
Jonathan N. BaumanAngela C. DoranAma King-AhmadRaman Sharma...
13页
查看更多>>摘要：Abrocitinib is an oral once-daily Janus kinase 1 selective inhibitor being developed for the treatment of moderate-to-severe atopic dermatitis. This study examined the disposition of abrocitinib in male participants following oral and intravenous administration using accelerator mass spectroscopy methodology to estimate pharmacokinetic parameters and characterize metabolite (M) profiles. The results indicated abrocitinib had a systemic clearance of 64.2 L/h, a steady-state volume of distribution of 100 L, extent of absorption >90%, time to maximum plasma concentration of~0.5 hours, and absolute oral bioavailability of 60%. The half-life of both abrocitinib and total radioactivity was similar, with no indication of metabolite accumulation. Abrocitinib was the main circulating drug species in plasma (~26%), with 3 major monohydroxylated metabolites (M1, M2, and M4) at >10%. Oxidative metabolism was the primary route of elimination for abrocitinib, with the greatest disposition of radioactivity shown in the urine (~85%). In vitro phenotyping indicated abrocitinib cytochrome P450 fraction of metabolism assignments of 0.53 for CYP2C19, 0.30 for CYP2C9, 0.11 for CYP3A4, and ~0.06 for CYP2B6. The principal systemic metabolites M1, M2, and M4 were primarily cleared renally. Abrocitinib, M1, and M2 showed pharmacology with similar Janus kinase 1 selectivity, whereas M4 was inactive.
Anika N. AhmedAmin Rostami-HodjeganJill BarberZubida M. Al-Majdoub...
7页
查看更多>>摘要：The default assumption during in vitro in vivo extrapolation (IVIVE) to predict metabolic clearance in physiologically based pharmaco-kinetics (PBPK) is that protein expression and activity have the same relationship in various tissues. This assumption is examined for uridine 5'-diphosphate glucuronosyltransferases (UGTs), a case example where expression and hence metabolic activity are distributed across various tissues. Our literature analysis presents overwhelming evidence of a greater UGT activity per unit of enzyme (higher k_cat) in kidney and intestinal tissues relative to liver (greater than 200-fold for UGT2B7). This analysis is based on application of abundance values reported using similar proteo-mic techniques and within the same laboratory. Our findings call into question the practice of assuming similar k_cat during IVIVE estimations as part of PBPK and call for a systematic assessment of the k_cat of various enzymes across different organs. The analysis focused on compiling data for probe substrates that were common for two or more of the studied tissues to allow for reliable comparison of cross-tissue enzyme kinetics; this meant that UGT enzymes included in the study were limited to UGT1A1, 1A3, 1A6, 1A9, and 2B7. Significantly, UGT1A9 (n = 24) and the liver (n = 27) were each found to account for around half of the total dataset; these were found to correlate with hepatic UGT1A9 data found in 15 of the studies, highlighting the need for more research into extrahepatic tissues and other UGT isoforms.
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