Reaction Phenotyping: Current Industry Efforts to Identify Enzymes Responsible for Metabolizing Drug Candidates

Harper, Timothy W.; Brassil, Patrick

doi:10.1208/s12248-008-9019-6

Cited by 57 publications

(32 citation statements)

References 37 publications

(27 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…xenobiotic metabolism. A number of reviews describe cytochrome P450 reaction phenotyping and substrate/inhibitor specificities of various P450 enzymes (Newton et al, 1995;Zhang et al, 2007;Harper and Brassil, 2008;Emoto et al, 2010). However, this review is not intended to restate this topic, but rather focus on emerging data.…”

Section: Discussion Cytochrome P450smentioning

confidence: 99%

Reaction Phenotyping: Advances in the Experimental Strategies Used to Characterize the Contribution of Drug-Metabolizing Enzymes

2014

View full text Add to dashboard Cite

During the process of drug discovery, the pharmaceutical industry is faced with numerous challenges. One challenge is the successful prediction of the major routes of human clearance of new medications. For compounds cleared by metabolism, accurate predictions help provide an early risk assessment of their potential to exhibit significant interpatient differences in pharmacokinetics via routes of metabolism catalyzed by functionally polymorphic enzymes and/or clinically significant metabolic drug-drug interactions. This review details the most recent and emerging in vitro strategies used by drug metabolism and pharmacokinetic scientists to better determine rates and routes of metabolic clearance and how to translate these parameters to estimate the amount these routes contribute to overall clearance, commonly referred to as fraction metabolized. The enzymes covered in this review include cytochrome P450s together with other enzymatic pathways whose involvement in metabolic clearance has become increasingly important as efforts to mitigate cytochrome P450 clearance are successful. Advances in the prediction of the fraction metabolized include newly developed methods to differentiate CYP3A4 from the polymorphic enzyme CYP3A5, scaling tools for UDP-glucuronosyltranferase, and estimation of fraction metabolized for substrates of aldehyde oxidase. IntroductionIn an era where combination drug therapy to treat several conditions simultaneously is common, drug companies emphasize the need for optimal absorption, distribution, metabolism, and excretion (ADME) properties, with the purpose of optimization of efficacy and minimization of the risk of adverse events. This includes a proper assignment and an extensive understanding of the routes of metabolism to aid in the prediction of human pharmacokinetics, and to help avoid a potential "object drug" scenario when coadministration is likely. The attributes of the coadministered drug and/or the patient has the potential to increase the probability of a drug-drug interaction (DDI), i.e., enzyme inhibitor, inducer, polymorphic genotype. Hence, the greater the percentage attributed to a single metabolic route, the greater the potential for a DDI and possible "black box warning" being issued as part of the drug package insert. Furthermore, the pharmacokinetic implications of a single polymorphic enzyme being responsible for a majority of the metabolism of a drug may have either an efficacy (extensive metabolizers) or toxicological (poor metabolizers) impact on exposure. To address these concerns, early drug discovery teams strive for balanced metabolism across multiple enzymes and clearance mechanisms (hepatic, renal, biliary). These discovery efforts center on in vitro reaction phenotyping to support enhanced chemical design.There is a general agreement among the major regulatory agencies that pharmaceutical companies should provide a characterization of the metabolic profile of a new chemical entity (NCE) and understand the enzymology of the major clearance mechanisms ...

show abstract

Section: Discussion Cytochrome P450smentioning

confidence: 99%

Reaction Phenotyping: Advances in the Experimental Strategies Used to Characterize the Contribution of Drug-Metabolizing Enzymes

2014

View full text Add to dashboard Cite

show abstract

“…MB07811 (5 M) was incubated in triplicate with microsomes prepared from baculovirus-infected insect cell lines containing (Drahushuk et al, 1998;Dennison et al, 2007;Harper and Brassil, 2008). Animal Studies.…”

Section: Methodsmentioning

confidence: 99%

“…The results indicated that CYP1A1, CYP2C8, CYP3A4, and CYP3A5 catalyzed the formation of MB07344 with the highest activity being attributed to CYP3A4. An evaluation of the intrinsic clearance of MB07811 in each of the P450 enzymes would be required to fully determine the relative importance of each of the individual P450 enzymes to the overall oxidative metabolism of MB07811 (Harper and Brassil, 2008). Pharmacokinetics of MB07811 after i.v.…”

Section: Kinetics Of Conversion Of Mb07811 To Mb07344 In Animal and Hmentioning

confidence: 99%

Preclinical Pharmacokinetics of a HepDirect Prodrug of a Novel Phosphonate-Containing Thyroid Hormone Receptor Agonist

Fujitaki

Cable²,

Ito³

et al. 2008

Drug Metab Dispos

View full text Add to dashboard Cite

The prodrug [(2R,4S)-4-(3-chlorophenyl)-2-[(3,5-dimethyl-4-(4-hydroxy-3-isopropylbenzyl)phenoxy)methyl]-2-oxido-[1,3,2]-dioxaphosphonane (MB07811)] of a novel phosphonate-containing thyroid hormone receptor agonist [3,5-dimethyl-4-(4-hydroxy-3-isopropylbenzyl)phenoxylmethylphosphonic acid (MB07344)] is the first application of the HepDirect liver-targeting approach to a non-nucleotide agent. The disposition of MB07811 was characterized in rat, dog, and monkey to assess its liver specificity, which is essential in limiting the extrahepatic side effects associated with this class of lipid-lowering agents. MB07811 was converted to MB07344 in liver microsomes from all species tested (CL int 1.23-145.4 l/min/mg). The plasma clearance and volume of distribution of MB07811 matched or exceeded 1 l/h/kg and 3 l/kg, respectively. Although absorption of prodrug was good, its absolute oral bioavailability as measured systemically was low (3-10%), an indication of an extensive hepatic first-pass effect. This effect was confirmed by comparison of systemic exposure levels of MB07811 after portal and jugular vein administration to rats, which demonstrated a hepatic extraction ratio of >0.6 with liver CYP3A-mediated conversion to MB07344 being a major component. The main route of elimination of MB07811 and MB07344 was biliary, with no evidence for enterohepatic recirculation of MB07344. Similar metabolic profiles of MB07811 were obtained in liver microsomes across the species tested. Tissue distribution and whole body autoradiography confirmed that the liver is the major target organ of MB07811 and that conversion to MB07344 was high in the liver relative to that in other tissues. Hepatic first-pass extraction and metabolism of MB07811, coupled with possible selective distribution of MB07811-derived MB07344, led to a high degree of liver targeting of MB07344.The thyroid hormones (T 3 and thyroxine) are important modulators of lipid homeostasis, thermogenesis, and metabolic rate (Yen, 2001). The effects of the thyroid hormones are widespread and arise from their binding to specific nuclear receptors found in most cell types and tissues (Hulbert, 2000). There are four main isoforms of thyroid hormone receptors (TRs), TR␣1, TR␣2, TR␤1, and TR␤2, which are expressed differentially in tissues (Lazar, 1993). The lipid-lowering activity of thyroid hormones and related analogs as a treatment for hypercholesterolemia and obesity has been demonstrated in animals as well as in humans (Krotkieswki, 2000). However, to date, the development of TR agonists as safe and effective agents to treat hypercholesterolemia and obesity has been hampered mainly by doselimiting cardiovascular toxicities, resulting in an insufficient safety window (Underwood et al., 1986). Because beneficial effects such as lowering of plasma cholesterol are mediated primarily by activation of the TR␤ isoform in liver (Forrest et al., 1996) and effects on cardiac function are mediated by TR␣ in heart (Wikstrom et al., 1998), one approach pursued to improve the th...

show abstract

“…Incubations without NADPH were used as negative controls. Control incubations using probe substrates for individual recombinant humans CYPs were included to check for appropriate incubation conditions and as positive control for activity [15]. The samples were analyzed on LC-MS/MS.…”

Section: Rhcyp Metabolismmentioning

confidence: 99%

Preclinical assessment of ulixertinib, a novel ERK1/2 inhibitor

Balakrishna

Hiremath²,

Raj³

et al. 2017

ADMET DMPK

View full text Add to dashboard Cite

Ulixertinib (BVD-523) is a novel and selective reversible inhibitor of ERK1/ERK2. In xenograft studies it inhibited tumor growth in BRAF-mutant melanoma and colorectal xenografts as well as KRAS-mutant colorectal and pancreatic models. Ulixertinib is currently in Phase I clinical development for the treatment of advance solid tumors. The objective of the study is to assess the metabolic stability (in various pre-clinical and human liver microsomes/hepatocytes), permeability, protein binding, CYP inhibition, CYP induction and CYP phenotyping of ulixertinib. We have also studied the oral and intravenous pharmacokinetics of ulixertinib in mice, rats and dogs. Ulixertinib was found to be moderately to highly stable in various liver microsomes/hepatocytes tested. It is a medium permeable (2.67 x 10-6 cm /sec) drug and a substrate for efflux (efflux ratio: 3.02) in Caco-2 model. Ulixertinib was highly bound to plasma proteins. CYPs involved in its limited metabolism and it is CYP inhibition IC50 ranged between 10-20 µM. Post oral administration ulixertinib exhibited early Tmax (0.50-0.75 h) in mice and rats indicating absorption was rapid, however in dogs Tmax attained at 2 h. The half-life (t½) of ulixertinib by intravenous and oral routes ranged between 1.0-2.5 h across the species. Clearance and volume of distribution by intravenous route for ulixertinib were found to be 6.24 mL/min/kg and 0.56 L/kg; 1.67 mL/min/kg and 0.36 L/kg and 15.5 mL/min/kg and 1.61 L/kg in mice, rats and dogs, respectively. Absolute oral bioavailability in mice and rats was > 92 %, however in dogs it was 34 %.

show abstract

Reaction Phenotyping: Current Industry Efforts to Identify Enzymes Responsible for Metabolizing Drug Candidates

Cited by 57 publications

References 37 publications

Reaction Phenotyping: Advances in the Experimental Strategies Used to Characterize the Contribution of Drug-Metabolizing Enzymes

Reaction Phenotyping: Advances in the Experimental Strategies Used to Characterize the Contribution of Drug-Metabolizing Enzymes

Preclinical Pharmacokinetics of a HepDirect Prodrug of a Novel Phosphonate-Containing Thyroid Hormone Receptor Agonist

Preclinical assessment of ulixertinib, a novel ERK1/2 inhibitor

Contact Info

Product

Resources

About