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Non-cytochrome P450 enzymes involved in the oxidative metabolism of xenobiotics: Focus on the regulation of gene expression and enzyme activity. Pharmacol Ther 2021; 233:108020. [PMID: 34637840 DOI: 10.1016/j.pharmthera.2021.108020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 09/25/2021] [Accepted: 10/04/2021] [Indexed: 12/16/2022]
Abstract
Oxidative metabolism is one of the major biotransformation reactions that regulates the exposure of xenobiotics and their metabolites in the circulatory system and local tissues and organs, and influences their efficacy and toxicity. Although cytochrome (CY)P450s play critical roles in the oxidative reaction, extensive CYP450-independent oxidative metabolism also occurs in some xenobiotics, such as aldehyde oxidase, xanthine oxidoreductase, flavin-containing monooxygenase, monoamine oxidase, alcohol dehydrogenase, or aldehyde dehydrogenase-dependent oxidative metabolism. Drugs form a large portion of xenobiotics and are the primary target of this review. The common reaction mechanisms and roles of non-CYP450 enzymes in metabolism, factors affecting the expression and activity of non-CYP450 enzymes in terms of inhibition, induction, regulation, and species differences in pharmaceutical research and development have been summarized. These non-CYP450 enzymes are detoxifying enzymes, although sometimes they mediate severe toxicity. Synthetic or natural chemicals serve as inhibitors for these non-CYP450 enzymes. However, pharmacokinetic-based drug interactions through these inhibitors have rarely been reported in vivo. Although multiple mechanisms participate in the basal expression and regulation of non-CYP450 enzymes, only a limited number of inducers upregulate their expression. Therefore, these enzymes are considered non-inducible or less inducible. Overall, this review focuses on the potential xenobiotic factors that contribute to variations in gene expression levels and the activities of non-CYP450 enzymes.
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Fowler S, Brink A, Cleary Y, Guenther A, Heinig K, Husser C, Kletzl H, Kratochwil NA, Mueller L, Savage M, Stillhart C, Tuerck DW, Ullah M, Umehara K, Poirier A. Addressing today's ADME challenges in the translation of in vitro absorption, distribution, metabolism and excretion characteristics to human: A case study of the SMN2 mRNA splicing modifier risdiplam. Drug Metab Dispos 2021; 50:65-75. [PMID: 34620695 DOI: 10.1124/dmd.121.000563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 09/30/2021] [Indexed: 11/22/2022] Open
Abstract
Small molecules that present complex absorption, distribution, metabolism, and elimination (ADME) properties can be challenging to investigate as potential therapeutics. Acquiring data through standard methods can yield results that are insufficient to describe the in vivo situation, which can affect downstream development decisions. Implementing in vitro - in vivo - in silico strategies throughout the drug development process is effective in identifying and mitigating risks while speeding up their development. Risdiplam (EVRYSDI®) - an orally bioavailable, small molecule approved by the U.S. Food and Drug Administration and more recently by the European Medicines Agency for the treatment of patients {greater than or equal to}2 months of age with spinal muscular atrophy (SMA), is presented here as a case study. Risdiplam is a low turnover compound whose metabolism is mediated through a non-cytochrome P450 enzymatic pathway. Four main challenges of risdiplam are discussed: predicting in vivo hepatic clearance, determining in vitro metabolites with regard to metabolites in safety testing guidelines, elucidating enzymes responsible for clearance, and estimating potential drug-drug interactions. A combination of in vitro and in vivo results was successfully extrapolated and used to develop a robust physiologically based pharmacokinetic model of risdiplam. These results were verified through early clinical studies, further strengthening the understanding of the ADME properties of risdiplam in humans. These approaches can be applied to other compounds with similar ADME profiles, which may be difficult to investigate using standard methods. Significance Statement Risdiplam is the first approved, small molecule, survival of motor neuron 2 mRNA splicing modifier for the treatment of spinal muscular atrophy. The approach taken to characterize the absorption, distribution, metabolism and excretion (ADME) properties of risdiplam during clinical development incorporated in vitro-in vivo-in silico techniques, which may be applicable to other small molecules with challenging ADME. These strategies may be useful in improving the speed at which future drug molecules can be developed.
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Affiliation(s)
| | - Andreas Brink
- Pharmaceutical Sciences, Roche Pharma Research and Early Development, F. Hoffmann-La Roche Ltd, Switzerland
| | - Yumi Cleary
- Pharmaceutical Sciences, Roche Pharma Research and Early Development, F. Hoffmann-La Roche Ltd, Switzerland
| | - Andreas Guenther
- Pharmaceutical Sciences, Roche Pharma Research and Early Development, F. Hoffmann-La Roche Ltd, Switzerland
| | - Katja Heinig
- Pharmaceutical Sciences, Roche Pharma Research and Early Development, F. Hoffmann-La Roche Ltd, Switzerland
| | | | - Heidemarie Kletzl
- Pharmaceutical Sciences, Roche Pharma Research and Early Development, F. Hoffmann-La Roche Ltd, Switzerland
| | | | - Lutz Mueller
- Pharmaceutical Sciences, Roche Pharma Research and Early Development, F. Hoffmann-La Roche Ltd, Switzerland
| | - Mark Savage
- Unilabs York Bioanalytical Solutions, United Kingdom
| | - Cordula Stillhart
- Formulation & Process Sciences, Pharmaceutical R&D, F. Hoffmann-La Roche Ltd, Switzerland
| | | | - Mohammed Ullah
- Pharmaceutical Sciences, Roche Pharmaceutical Research and Early Development, Switzerland
| | - Kenichi Umehara
- Pharmaceutical Sciences, Roche Pharmaceutical Research and Early Development, Switzerland
| | - Agnès Poirier
- Pharmaceutical Sciences, F.Hoffmann-La Roche, Switzerland
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Wang X, Bell IM, Uslaner JM. Activators of α7 nAChR as Potential Therapeutics for Cognitive Impairment. Curr Top Behav Neurosci 2020; 45:209-245. [PMID: 32451955 DOI: 10.1007/7854_2020_140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The α7 nicotinic acetylcholine receptor (nAChR) is a promising target for the treatment of cognitive deficits associated with psychiatric and neurological disorders, including schizophrenia and Alzheimer's disease (AD). Several α7 nAChR agonists and positive allosteric modulators (PAMs) have demonstrated procognitive effects in preclinical models and early clinical trials. However, despite intense research efforts in the pharmaceutical industry and academia, none of the α7 nAChR ligands has been approved for clinical use. This chapter will focus on the α7 nAChR ligands that have advanced to clinical studies and explore the reasons why these agents have not met with unequivocal clinical success.
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Affiliation(s)
- Xiaohai Wang
- Department of Neuroscience Research, Merck & Co. Inc., West Point, PA, USA
| | - Ian M Bell
- Department of Discovery Chemistry, Merck & Co. Inc., West Point, PA, USA
| | - Jason M Uslaner
- Department of Neuroscience Research, Merck & Co. Inc., West Point, PA, USA.
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Tregellas JR, Wylie KP. Alpha7 Nicotinic Receptors as Therapeutic Targets in Schizophrenia. Nicotine Tob Res 2019; 21:349-356. [PMID: 30137618 DOI: 10.1093/ntr/nty034] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/09/2018] [Indexed: 12/12/2022]
Abstract
While current treatments for schizophrenia often provide much relief for positive symptoms such as hallucinations, other symptoms, particularly cognitive deficits, persist and contribute to substantial suffering and reduced quality of life for patients. In searching for novel therapeutic avenues to treat cognitive deficits in schizophrenia, recent work is exploring nicotinic receptor neurobiology. Supported by a large body of evidence, with contributions from studies of smoking behaviors, genetics, receptor distribution and function, animal models and nicotinic effects on illness symptoms, the alpha7 nicotinic receptor has emerged as a potential therapeutic target. Despite promise in early clinical trials, however, no drug targeting nicotinic systems has succeeded in larger phase 3 trials. Following a brief review of nicotinic receptor biology and the evidence that has led to pursuit of alpha7 nicotinic agonism as a therapeutic strategy, this review will provide an update on the status of recent trials, discuss potential issues that may have contributed to negative outcomes, and point to new directions and promising advances in developing alpha7 nicotinic receptor-based treatment for cognitive symptoms in schizophrenia. IMPLICATIONS By examining alpha7 nicotinic receptor biology and recent efforts to target the receptor in clinical trials, it is hoped that investigators will be motivated to explore novel, promising directions focusing on the receptor as a strategy to treat cognitive symptoms in schizophrenia.
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Affiliation(s)
- Jason R Tregellas
- Department of Psychiatry, University of Colorado School of Medicine, Aurora, CO.,Research Service, Denver VA Medical Center, Denver, CO
| | - Korey P Wylie
- Department of Psychiatry, University of Colorado School of Medicine, Aurora, CO.,Research Service, Denver VA Medical Center, Denver, CO
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