1
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Sunzel EM, Rabinovich-Guilatt L, Iyengar M, Ruffo D, Birajdar NG, Loupe P, Gutierrez M, Gordon MF, Ghibellini G. A Bioequivalence Comparison Between the Once-Daily Extended-Release Tablet and the Twice-Daily Tablet Formulations of Deutetrabenazine at Steady State. Clin Pharmacol Drug Dev 2024; 13:224-232. [PMID: 38214040 DOI: 10.1002/cpdd.1355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 11/28/2023] [Indexed: 01/13/2024]
Abstract
Deutetrabenazine is approved for the treatment of tardive dyskinesia and chorea associated with Huntington's disease. This study compared the exposure between the once-daily (test) and twice-daily (reference) formulations of deutetrabenazine under fed conditions. Using a randomized crossover design, healthy adults (n = 262) received the 24 mg of the test formulation once daily and 12 mg of the reference formulation twice daily, each for 7 days. Plasma concentrations were collected on Days 4-6 before dose intake, and frequently for pharmacokinetic evaluation on Days 6 and 7 for determination of deutetrabenazine and active metabolites, deuterated α-dihydrotetrabenazine (α-HTBZ) and β-dihydrotetrabenazine (β-HTBZ). Geometric mean ratios (GMRs, test/reference) were computed for all analytes, and bioequivalence was tested for area under the plasma concentration-time curve over 24 hours at steady state (AUC0-24 h,ss ) and for maximum plasma concentrations at steady state (Cmax,ss ). The GMRs for AUC0-24 h,ss were 115% for deutetrabenazine and 95% for deuterated total (α+β)-HTBZ; and the GMR for Cmax,ss for deutetrabenazine was 95%. Relative bioavailability was assessed for Cmax,ss of the active metabolites; the GMR was 78% for total (α+β)-HTBZ. At steady state, deutetrabenazine administered as the once-daily formulation was bioequivalent to the twice-daily formulation for both AUC and Cmax, and the active metabolites were bioequivalent with regard to AUC0-24 h,ss .
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Affiliation(s)
- Eva-Maria Sunzel
- Innovative Medicines R&D Global Clinical Development, Teva Pharmaceuticals, West Chester, PA, USA
| | | | - Malini Iyengar
- Innovative Medicines R&D Global Clinical Development, Teva Pharmaceuticals, West Chester, PA, USA
| | - Debra Ruffo
- Innovative Medicines R&D Global Clinical Development, Teva Pharmaceuticals, West Chester, PA, USA
| | | | - Pippa Loupe
- Innovative Medicines R&D Global Clinical Development, Teva Pharmaceuticals, West Chester, PA, USA
| | | | - Mark Forrest Gordon
- Innovative Medicines R&D Global Clinical Development, Teva Pharmaceuticals, West Chester, PA, USA
| | - Giulia Ghibellini
- Innovative Medicines R&D Global Clinical Development, Teva Pharmaceuticals, West Chester, PA, USA
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2
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Subbaiah MAM, Rautio J, Meanwell NA. Prodrugs as empowering tools in drug discovery and development: recent strategic applications of drug delivery solutions to mitigate challenges associated with lead compounds and drug candidates. Chem Soc Rev 2024; 53:2099-2210. [PMID: 38226865 DOI: 10.1039/d2cs00957a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
The delivery of a drug to a specific organ or tissue at an efficacious concentration is the pharmacokinetic (PK) hallmark of promoting effective pharmacological action at a target site with an acceptable safety profile. Sub-optimal pharmaceutical or ADME profiles of drug candidates, which can often be a function of inherently poor physicochemical properties, pose significant challenges to drug discovery and development teams and may contribute to high compound attrition rates. Medicinal chemists have exploited prodrugs as an informed strategy to productively enhance the profiles of new chemical entities by optimizing the physicochemical, biopharmaceutical, and pharmacokinetic properties as well as selectively delivering a molecule to the site of action as a means of addressing a range of limitations. While discovery scientists have traditionally employed prodrugs to improve solubility and membrane permeability, the growing sophistication of prodrug technologies has enabled a significant expansion of their scope and applications as an empowering tool to mitigate a broad range of drug delivery challenges. Prodrugs have emerged as successful solutions to resolve non-linear exposure, inadequate exposure to support toxicological studies, pH-dependent absorption, high pill burden, formulation challenges, lack of feasibility of developing solid and liquid dosage forms, first-pass metabolism, high dosing frequency translating to reduced patient compliance and poor site-specific drug delivery. During the period 2012-2022, the US Food and Drug Administration (FDA) approved 50 prodrugs, which amounts to 13% of approved small molecule drugs, reflecting both the importance and success of implementing prodrug approaches in the pursuit of developing safe and effective drugs to address unmet medical needs.
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Affiliation(s)
- Murugaiah A M Subbaiah
- Department of Medicinal Chemistry, Biocon Bristol Myers Squibb R&D Centre, Biocon Park, Bommasandra Phase IV, Bangalore, PIN 560099, India.
| | - Jarkko Rautio
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Nicholas A Meanwell
- The Baruch S. Blumberg Institute, Doylestown, PA 18902, USA
- Department of Medicinal Chemistry, The College of Pharmacy, The University of Michigan, Ann Arbor, MI 48109, USA
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3
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Uchiyama H, Ban K, Nozaki S, Ikeda Y, Ishimoto T, Fujioka H, Kamiya M, Amari R, Tsujino H, Arai M, Yamazoe S, Maekawa K, Kato T, Doi M, Kadota K, Tozuka Y, Tomita N, Sajiki H, Akai S, Sawama Y. Impact of multiple H/D replacements on the physicochemical properties of flurbiprofen. RSC Med Chem 2023; 14:2583-2592. [PMID: 38107175 PMCID: PMC10718516 DOI: 10.1039/d3md00357d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 10/06/2023] [Indexed: 12/19/2023] Open
Abstract
Although deuterium incorporation into pharmaceutical drugs is an attractive way to expand drug modalities, their physicochemical properties have not been sufficiently examined. This study focuses on examining the changes in physicochemical properties between flurbiprofen (FP) and flurbiprofen-d8 (FP-d8), which was successfully prepared by direct and multiple H/D exchange reactions at the eight aromatic C-H bonds of FP. Although the effect of deuterium incorporation was not observed between the crystal structures of FP and FP-d8, the melting point and heat of fusion of FP-d8 were lower than those of FP. Additionally, the solubility of FP-d8 increased by 2-fold compared to that of FP. Calculation of the interaction energy between FP/FP-d8 and water molecules using the multi-component density functional theory method resulted in increased solubility of FP-d8. These novel and valuable findings regarding the changes in physicochemical properties triggered by deuterium incorporation can contribute to the further development of deuterated drugs.
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Affiliation(s)
- Hiromasa Uchiyama
- Department of Formulation Design and Pharmaceutical Technology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University 4-20-1 Nasahara Takatsuki Osaka 569-1094 Japan
| | - Kazuho Ban
- Graduate School of Pharmaceutical Sciences, Osaka University 1-6, Yamada-oka Suita Osaka 565-0871 Japan
| | - Shiho Nozaki
- Graduate School of Pharmaceutical Sciences, Osaka University 1-6, Yamada-oka Suita Osaka 565-0871 Japan
| | - Yui Ikeda
- Department of Formulation Design and Pharmaceutical Technology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University 4-20-1 Nasahara Takatsuki Osaka 569-1094 Japan
| | - Takayoshi Ishimoto
- Graduate School of Advanced Science and Engineering, Hiroshima University 1-4-1 Kagamiyama Higashi-Hiroshima Hiroshima 739-8527 Japan
| | - Hiroyoshi Fujioka
- Department of Life Science and Technology, Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama Kanagawa 226-8501 Japan
| | - Mako Kamiya
- Department of Life Science and Technology, Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama Kanagawa 226-8501 Japan
- Living Systems Materialogy (LiSM) Research Group, International Research Frontiers Initiative (IRFI), Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama Kanagawa 226-8501 Japan
| | - Ryugo Amari
- Graduate School of Pharmaceutical Sciences, Osaka University 1-6, Yamada-oka Suita Osaka 565-0871 Japan
| | - Hirofumi Tsujino
- Graduate School of Pharmaceutical Sciences, Osaka University 1-6, Yamada-oka Suita Osaka 565-0871 Japan
| | - Masayoshi Arai
- Graduate School of Pharmaceutical Sciences, Osaka University 1-6, Yamada-oka Suita Osaka 565-0871 Japan
| | - Sachi Yamazoe
- Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts 97-1 Minamihokodate Koudo Kyotanabe, Kyoto 610-0395 Japan
| | - Keiko Maekawa
- Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts 97-1 Minamihokodate Koudo Kyotanabe, Kyoto 610-0395 Japan
| | - Takuma Kato
- Department of Formulation Design and Pharmaceutical Technology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University 4-20-1 Nasahara Takatsuki Osaka 569-1094 Japan
| | - Mitsunobu Doi
- Department of Formulation Design and Pharmaceutical Technology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University 4-20-1 Nasahara Takatsuki Osaka 569-1094 Japan
| | - Kazunori Kadota
- Department of Formulation Design and Pharmaceutical Technology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University 4-20-1 Nasahara Takatsuki Osaka 569-1094 Japan
| | - Yuichi Tozuka
- Department of Formulation Design and Pharmaceutical Technology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University 4-20-1 Nasahara Takatsuki Osaka 569-1094 Japan
| | - Naohito Tomita
- Gifu Pharmaceutical University 1-25-4-Daigaku-nishi Gifu 501-1196 Japan
| | - Hironao Sajiki
- Gifu Pharmaceutical University 1-25-4-Daigaku-nishi Gifu 501-1196 Japan
| | - Shuji Akai
- Graduate School of Pharmaceutical Sciences, Osaka University 1-6, Yamada-oka Suita Osaka 565-0871 Japan
| | - Yoshinari Sawama
- Graduate School of Pharmaceutical Sciences, Osaka University 1-6, Yamada-oka Suita Osaka 565-0871 Japan
- Deuterium Science Research Unit, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University Yoshida, Sakyo-ku Kyoto 606-8501 Japan
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4
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Ban K, Imai K, Oyama S, Tokunaga J, Ikeda Y, Uchiyama H, Kadota K, Tozuka Y, Akai S, Sawama Y. Sulfonium Salt Reagents for the Introduction of Deuterated Alkyl Groups in Drug Discovery. Angew Chem Int Ed Engl 2023; 62:e202311058. [PMID: 37726202 DOI: 10.1002/anie.202311058] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 09/21/2023]
Abstract
The pharmacokinetics of pharmaceutical drugs can be improved by replacing C-H bonds with the more stable C-D bonds at the α-position to heteroatoms, which is a typical metabolic site for cytochrome P450 enzymes. However, the application of deuterated synthons is limited. Herein, we established a novel concept for preparing deuterated reagents for the successful synthesis of complex drug skeletons with deuterium atoms at the α-position to heteroatoms. (dn -Alkyl)diphenylsulfonium salts prepared from the corresponding nondeuterated forms using inexpensive and abundant D2 O as the deuterium source with a base, were used as electrophilic alkylating reagents. Additionally, these deuterated sulfonium salts were efficiently transformed into dn -alkyl halides and a dn -alkyl azide as coupling reagents and a dn -alkyl amine as a nucleophile. Furthermore, liver microsomal metabolism studies revealed deuterium kinetic isotope effects (KIE) in 7-(d2 -ethoxy)flavone. The present concept for the synthesis of deuterated reagents and the first demonstration of a KIE in a d2 -ethoxy group will contribute to drug discovery research based on deuterium chemistry.
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Affiliation(s)
- Kazuho Ban
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Keisuke Imai
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Shuki Oyama
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Jin Tokunaga
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Yui Ikeda
- Department of Formulation Design and Pharmaceutical Technology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan
| | - Hiromasa Uchiyama
- Department of Formulation Design and Pharmaceutical Technology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan
| | - Kazunori Kadota
- Department of Formulation Design and Pharmaceutical Technology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan
| | - Yuichi Tozuka
- Department of Formulation Design and Pharmaceutical Technology, Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan
| | - Shuji Akai
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Yoshinari Sawama
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamada-oka, Suita, Osaka, 565-0871, Japan
- Deuterium Science Research Unit, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
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5
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Di Martino RMC, Maxwell BD, Pirali T. Deuterium in drug discovery: progress, opportunities and challenges. Nat Rev Drug Discov 2023; 22:562-584. [PMID: 37277503 PMCID: PMC10241557 DOI: 10.1038/s41573-023-00703-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2023] [Indexed: 06/07/2023]
Abstract
Substitution of a hydrogen atom with its heavy isotope deuterium entails the addition of one neutron to a molecule. Despite being a subtle change, this structural modification, known as deuteration, may improve the pharmacokinetic and/or toxicity profile of drugs, potentially translating into improvements in efficacy and safety compared with the non-deuterated counterparts. Initially, efforts to exploit this potential primarily led to the development of deuterated analogues of marketed drugs through a 'deuterium switch' approach, such as deutetrabenazine, which became the first deuterated drug to receive FDA approval in 2017. In the past few years, the focus has shifted to applying deuteration in novel drug discovery, and the FDA approved the pioneering de novo deuterated drug deucravacitinib in 2022. In this Review, we highlight key milestones in the field of deuteration in drug discovery and development, emphasizing recent and instructive medicinal chemistry programmes and discussing the opportunities and hurdles for drug developers, as well as the questions that remain to be addressed.
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Affiliation(s)
| | | | - Tracey Pirali
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy.
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6
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Wood D, Lin S. Deuterodehalogenation Under Net Reductive or Redox-Neutral Conditions Enabled by Paired Electrolysis. Angew Chem Int Ed Engl 2023; 62:e202218858. [PMID: 36738472 PMCID: PMC10050105 DOI: 10.1002/anie.202218858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/06/2023]
Abstract
Interest in deuterated active pharmaceutical ingredients (APIs) is increasing as deuteration holds promise for kinetic isotope effect (KIE) regulated fine-tuning of API performance. Moreover, deuterium isotope labeling is frequently carried out to study organic and bioorganic reaction mechanisms and to facilitate complex target synthesis. As such, methods for highly selective deuteration of organic molecules are highly desirable. Herein, we present an electrochemical method for the selective deuterodehalogenation of benzylic halides via a radical-polar crossover mechanism, using inexpensive deuterium oxide (D2 O) as the deuterium source. We demonstrate broad functional group compatibility across a range of aryl and heteroaryl benzylic halides. Furthermore, we uncover a sequential paired electrolysis regime, which permits switching between net reductive and overall redox-neutral reactions of sulfur-containing substrates simply by changing the identity of the sacrificial reductant employed.
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Affiliation(s)
- Devin Wood
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY-14853, USA
| | - Song Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY-14853, USA
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7
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Analysis of orphan designation status for FDA approved drugs, and case studies in oncology, neuroscience and metabolic diseases. Bioorg Med Chem 2023; 80:117170. [PMID: 36696875 DOI: 10.1016/j.bmc.2023.117170] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/20/2022] [Accepted: 01/09/2023] [Indexed: 01/19/2023]
Abstract
Many new drugs have been approved over the past decade for rare or orphan diseases. The passage of the Orphan Drug Act (ODA) in 1983 has provided key economic and regulatory incentives to provide medicines for patients who are suffering from rare diseases that may not be commercially attractive for research and development. We have analyzed 497 novel drugs approved from 2010 - June 13, 2022, of which 220 were given orphan designation status. We discuss trends over this time period, potential risks for long development times, and provide example case studies of successful development and launch of novel drugs for rare diseases.
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8
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Schneider F, Darpo B, Loupe PS, Xue H, Knebel H, Gutierrez M, Gordon MF, Rabinovich-Guilatt L. Evaluation of Deutetrabenazine's Potential to Delay Cardiac Repolarization Using Concentration-QTc Analysis. Clin Pharmacol Drug Dev 2023; 12:94-106. [PMID: 36098670 PMCID: PMC10086964 DOI: 10.1002/cpdd.1161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 07/27/2022] [Indexed: 01/09/2023]
Abstract
Deutetrabenazine (Austedo) is indicated in adults for chorea associated with Huntington disease and tardive dyskinesia. Escalating deutetrabenazine doses were administered to healthy volunteers who were cytochrome P450 2D6 extensive/intermediate metabolizers (EMs) or poor metabolizers (PMs) to determine pharmacokinetic exposure of parent drug and active metabolites (α-dihydrotetrabenazine [α-HTBZ] and β-dihydrotetrabenazine [β-HTBZ]), and collect corresponding electrocardiograms (ECGs) for evaluation of the cardiodynamic effect using concentration-QTc (C-QTc) modeling. Participants (12 EMs, 24 PMs) received placebo or single doses of deutetrabenazine (24, 48, and 72 mg) to achieve plasma concentrations exceeding therapeutic range in both cohorts. Pharmacokinetic samples were obtained over 72 hours after dosing and were time matched with 12-lead ECGs extracted from continuous ECG recordings. C-QTc analysis, using linear mixed-effects modeling and model selection procedure, characterized the relationship between plasma concentrations of deutetrabenazine, deuterated α-HTBZ and β-HTBZ, and the change from baseline in QT interval corrected using Fridericia's formula. Deutetrabenazine exhibited linear kinetics, and a C-QTc model with deuterated α-HTBZ and β-HTBZ was selected to best describe the C-QTc relationship in pooled EM and PM data. This model predicted a placebo-corrected Fridericia corrected QT interval prolongation higher than 10 milliseconds can be excluded at concentrations associated with the maximum recommended doses in both populations. Adverse events increased with higher exposure as reflected by the higher event number in the PM cohort receiving 48 and 72 mg doses. No subject discontinued due to cardiac-related adverse events and no clinically relevant ECG findings were reported. Thus, this study found that deutetrabenazine does not have a clinically relevant effect on QT prolongation at maximum recommended doses in either cytochrome P450 2D6 EMs or PMs.
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Affiliation(s)
| | | | - Pippa S Loupe
- Teva Pharmaceuticals, West Chester, Pennsylvania, USA
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9
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Brar S, Vijan A, Scott FL, Jimenez R, Zhang H, Grigoriadis DE, Loewen G. Pharmacokinetic and Pharmacologic Characterization of the Dihydrotetrabenazine Isomers of Deutetrabenazine and Valbenazine. Clin Pharmacol Drug Dev 2022; 12:447-456. [PMID: 36530055 DOI: 10.1002/cpdd.1205] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 11/07/2022] [Indexed: 12/23/2022]
Abstract
Valbenazine and deutetrabenazine are vesicular monoamine transporter 2 (VMAT2) inhibitors approved for tardive dyskinesia. The clinical activity of valbenazine is primarily attributed to its only dihydrotetrabenazine (HTBZ) metabolite, [+]-α-HTBZ. Deutetrabenazine is a deuterated form of tetrabenazine and is metabolized to four deuterated HTBZ metabolites: [+]-α-deuHTBZ, [+]-β-deuHTBZ, [-]-α-deuHTBZ, and [-]-β-deuHTBZ. An open-label, crossover study characterized the pharmacokinetic profiles of the individual deuHBTZ metabolites, which have not been previously reported. VMAT2 inhibition and off-target interactions of the deuHTBZ metabolites were evaluated using radioligand binding. The only valbenazine HTBZ metabolite, [+]-α-HTBZ, was a potent VMAT2 inhibitor, with negligible affinity for off-target dopamine, serotonin, and adrenergic receptors. Following deutetrabenazine administration, [-]-α-deuHTBZ represented 66% of circulating deuHTBZ metabolites and was a relatively weak VMAT2 inhibitor with appreciable affinity for dopamine (D2S , D3 ) and serotonin (5-HT1A , 5-HT2B , 5-HT7 ) receptors. [+]-β-deuHTBZ was the most abundant deuHTBZ metabolite that potently inhibited VMAT2, but it represented only 29% of total circulating deuHTBZ metabolites. The mean half-life of [+]-α-HTBZ (22.2 hours) was ∼3× longer than that of [+]-β-deuHTBZ (7.7 hours). These findings are similar to studies with tetrabenazine, in that deutetrabenazine is metabolized to four deuHTBZ stereoisomers, the most abundant of which has negligible interaction with VMAT2 in vitro and appreciable affinity for several off-target receptors. In contrast, valbenazine's single HTBZ metabolite is a potent VMAT2 inhibitor in vitro with no discernible off-target activity. Determination of the effects of intrinsic/extrinsic variables on deutetrabenazine's safety/efficacy profile should incorporate assessment of the effects on all deuHTBZ metabolites.
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Affiliation(s)
- Satjit Brar
- Neurocrine Biosciences, Inc. San Diego California USA
| | - Arjun Vijan
- Neurocrine Biosciences, Inc. San Diego California USA
| | | | | | - Hui Zhang
- Neurocrine Biosciences, Inc. San Diego California USA
| | | | - Gordon Loewen
- Neurocrine Biosciences, Inc. San Diego California USA
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10
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Gupta H, Perkins W, Stark C, Kikkeri S, Kakazu J, Kaye A, Kaye A. deutetrabenazine for the treatment of chorea associated with Huntington's disease. Health Psychol Res 2022; 10:36040. [PMID: 35774908 DOI: 10.52965/001c.36040] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 01/04/2022] [Indexed: 11/06/2022] Open
Abstract
This is a comprehensive review of the literature regarding the use of Deutetrabenazine in treating chorea associated with Huntington's disease. Unfortunately, treatment has been limited for many aspects of this neurodegenerative disease. The present investigation presents the background, evidence, and indications for the use Deutetrabenazine in the setting of Huntington's disease. Huntington's disease is characterized by a variety of motor, psychiatric, and cognitive symptoms with chorea being one of the more notable ones. Chorea is a movement disorder present in multiple neurologic diseases that causes involuntary and irregular muscle movements theorized to be stemming from high dopamine levels. Deutetrabenazine is thought to function as an inhibitor of the VMAT2 vesicular monoamine transporter resulting in decreased monoamine release, including dopamine, in the synaptic cleft which has a therapeutic effect in management of chorea. This drug was approved by the FDA in 2017 with a specific indication for tardive dyskinesia and choreiform movement in Huntington's disease. Currently, there is no definitive treatment for Huntington's disease. Thus, management is primarily focused on symptom management with the use of a variety of pharmaceutical agents. Chorea is one of the many manifestations that significantly alter the quality of life of many patients. Deutetrabenazine is a promising new option for the treatment of chorea in the setting of Huntington's disease. Although studies so far have displayed mixed results, further research, including head-to-head studies, is necessary to elucidate the true potential of this drug.
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Affiliation(s)
| | - Wil Perkins
- School of Medicine, Louisiana State University Shreveport School of Medicine
| | - Cain Stark
- School of Medicine, Medical College of Wisconsin
| | - Sathya Kikkeri
- School of Osteopathic Medicine, Alabama College of Osteopathic Medicine
| | - Juyeon Kakazu
- School of Medicine, Georgetown University School of Medicine
| | - Adam Kaye
- School of Pharmacy, Thomas J. Long School of Pharmacy and Health Sciences
| | - Alan Kaye
- Anesthesiology, Louisiana State University Shreveport
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11
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Warren B, Vanderhoef D, Johnson J. VMAT2 Inhibitors for the Treatment of Tardive Dyskinesia. Issues Ment Health Nurs 2022; 43:22-31. [PMID: 34370608 DOI: 10.1080/01612840.2021.1948643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Psychiatric nurses are at the forefront of optimizing psychiatric care, including educating patients and caregivers on the risks of antipsychotic-induced movement disorders such as tardive dyskinesia (TD). Nurses should be aware that all patients taking antipsychotics should be regularly monitored for the development of TD. Given the current pandemic and increase in telehealth, assessing for TD is challenging; however, evaluation can be successfully completed by implementing the best practices described in this paper. Once TD is diagnosed, nurses can reassure patients that safe and effective FDA-approved treatments for TD (e.g., valbenazine) are now available.
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Affiliation(s)
- Barbara Warren
- Psychiatric Nursing Program, The Ohio State University College of Nursing, Columbus, Ohio, USA
| | - Dawn Vanderhoef
- Medical Affairs, Neurocrine Biosciences, Inc., San Diego, California, USA
| | - Jessica Johnson
- Medical Affairs, Neurocrine Biosciences, Inc., San Diego, California, USA
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12
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Wang W, Du G, Lin S, Liu J, Yang H, Yu D, Ye L, Zou F, Wang H, Zhang R, Tian J. (+)-9-Trifluoroethoxy-α-Dihydrotetrabenazine as a Highly Potent Vesicular Monoamine Transporter 2 Inhibitor for Tardive Dyskinesia. Front Pharmacol 2021; 12:770377. [PMID: 34950030 PMCID: PMC8689140 DOI: 10.3389/fphar.2021.770377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 11/22/2021] [Indexed: 12/02/2022] Open
Abstract
Valbenazine and deutetrabenazine are the only two therapeutic drugs approved for tardive dyskinesia based on blocking the action of vesicular monoamine transporter 2 (VMAT2). But there exist demethylated inactive metabolism at the nine position for both them resulting in low availability, and CYP2D6 plays a major role in this metabolism resulting in the genetic polymorphism issue. 9-trifluoroethoxy-dihydrotetrabenazine (13e) was identified as a promising lead compound for treating tardive dyskinesia. In this study, we separated 13e via chiral chromatography and acquired R,R,R-13e [(+)-13e] and S,S,S-13e [(−)-13e], and we investigated their VMAT2-inhibitory activity and examined the related pharmacodynamics and pharmacokinetics properties using in vitro and in vivo models (+)-13e displayed high affinity for VMAT2 (Ki = 1.48 nM) and strongly inhibited [3H]DA uptake (IC50 = 6.11 nM) in striatal synaptosomes. Conversely, its enantiomer was inactive. In vivo, (+)-13e decreased locomotion in rats in a dose-dependent manner. The treatment had faster, stronger, and longer-lasting effects than valbenazine at an equivalent dose. Mono-oxidation was the main metabolic pathway in the liver microsomes and in dog plasma after oral administration, and glucuronide conjugation of mono-oxidized and/or demethylated products and direct glucuronide conjugation were also major metabolic pathways in dog plasma. O-detrifluoroethylation of (+)-13e did not occur. Furthermore, CYP3A4 was identified as the primary isoenzyme responsible for mono-oxidation and demethylation metabolism, and CYP2C8 was a secondary isoenzyme (+)-13e displayed high permeability across the Caco-2 cell monolayer, and it was not a P-glycoprotein substrate as demonstrated by its high oral absolute bioavailability (75.9%) in dogs. Thus, our study findings highlighted the potential efficacy and safety of (+)-13e in the treatment of tardive dyskinesia. These results should promote its clinical development.
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Affiliation(s)
- Wenyan Wang
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Guangying Du
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Shilan Lin
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Jing Liu
- New Drug Discovery and Research Department, R&D Center, Luye Pharma Group Ltd., Yantai, China
| | - Huijie Yang
- New Drug Discovery and Research Department, R&D Center, Luye Pharma Group Ltd., Yantai, China
| | - Dawei Yu
- New Drug Discovery and Research Department, R&D Center, Luye Pharma Group Ltd., Yantai, China
| | - Liang Ye
- Department of Clinical Medicine, Binzhou Medical College, Yantai, China
| | - Fangxia Zou
- New Drug Discovery and Research Department, R&D Center, Luye Pharma Group Ltd., Yantai, China
| | - Hongbo Wang
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Rui Zhang
- New Drug Discovery and Research Department, R&D Center, Luye Pharma Group Ltd., Yantai, China
| | - Jingwei Tian
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
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Real-World Adherence to Tetrabenazine or Deutetrabenazine Among Patients With Huntington's Disease: A Retrospective Database Analysis. Neurol Ther 2021; 11:435-448. [PMID: 34905160 PMCID: PMC8857359 DOI: 10.1007/s40120-021-00309-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/26/2021] [Indexed: 11/06/2022] Open
Abstract
Introduction Chorea, a common clinical manifestation of Huntington’s disease (HD), involves sudden, involuntary movements that interfere with daily functioning and contribute to the morbidity of HD. Tetrabenazine and deutetrabenazine are FDA-approved to treat chorea associated with HD. Compared to tetrabenazine, deutetrabenazine has a unique pharmacokinetic profile leading to more consistent systemic exposure, less frequent dosing, and a potentially more favorable safety/tolerability profile. Real-world adherence data for these medications are limited. Here, we evaluate real-world adherence patterns with the vesicular monoamine transporter 2 inhibitors, tetrabenazine and deutetrabenazine, among patients diagnosed with HD. Methods Insurance claims data from the Symphony Health Solutions Integrated Dataverse (05/2017–05/2019) were retrospectively analyzed for patients diagnosed with HD (ICD-10-CM code G10). Patients were categorized into cohorts based on treatment. Outcomes included adherence, which was measured by proportion of days covered (PDC), adherence rate (PDC > 80%), and discontinuation rates during the 6-month follow-up period (after a 30-day dose stabilization period). Results Patient demographic characteristics between the deutetrabenazine (N = 281) and tetrabenazine (N = 101) cohorts were comparable at baseline. Mean ± SD PDC was significantly higher in the deutetrabenazine versus tetrabenazine cohort (78.5% ± 26.7% vs. 69.3% ± 31.4%; P < 0.01). Similarly, a higher adherence rate was observed in the deutetrabenazine versus tetrabenazine cohort, though the difference was not statistically significant (64.1% vs. 55.4%; P = 0.1518). Discontinuation rates were significantly lower in the deutetrabenazine versus tetrabenazine cohort during the 6-month follow-up period (1 month, 3.5% vs. 9.2%; 3 months, 14.7% vs. 23.3%; 6 months, 25.4% vs. 37.2%; P < 0.05). Conclusions Results from this real-world analysis indicate that patients treated with deutetrabenazine are more adherent to treatment and have lower discontinuation rates compared with patients in the tetrabenazine cohort. However, a potential limitation is overestimated adherence, as claims for prescription fills may not capture actual use. Additional research is warranted to explore the differences in adherence patterns between treatments, which may inform treatment decision-making. Supplementary Information The online version contains supplementary material available at 10.1007/s40120-021-00309-5.
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Chen MC, Korth CC, Harnett MD, Elenko E, Lickliter JD. A Randomized Phase 1 Evaluation of Deupirfenidone, a Novel Deuterium-Containing Drug Candidate for Interstitial Lung Disease and Other Inflammatory and Fibrotic Diseases. Clin Pharmacol Drug Dev 2021; 11:220-234. [PMID: 34779583 DOI: 10.1002/cpdd.1040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 09/19/2021] [Indexed: 11/07/2022]
Abstract
LYT-100 (deupirfenidone) is a selectively deuterated form of pirfenidone under development for the treatment of inflammatory and fibrotic diseases, including interstitial lung disease. Adverse events associated with antifibrotics can be a barrier to adoption and persistence in patients with interstitial lung diseases, most of whom are not on standard-of-care therapy. LYT-100 is designed to have a differentiated pharmacokinetic (PK) profile from pirfenidone and could offer a differentiated safety profile compared to current standard-of-care drugs while retaining the biochemical potency and specificity of pirfenidone. We conducted a phase 1b study to ascertain the safety, tolerability, steady-state PK profile, and food effect of LYT-100. This was a 2-part study. Part 1 assessed multiple ascending doses of LYT-100 from 100, 250, 500, 750, and 1000 mg twice daily given over 5 days without titration. Part 2 assessed the effects of fed vs fasting conditions on the PK profile of a single 500-mg dose of LYT-100. All doses up to 1000 mg were well tolerated, with adverse events being mild and transient. Exposure was slightly lower in the fed condition. LYT-100 was well tolerated and has a dose-proportional PK profile. The ratio of parent to major metabolite concentration was higher than reported with pirfenidone, which is consistent with an effect of deuteration on metabolism. No maximum tolerated dose was identified up to 1000 mg twice-daily dosing. These results support further clinical development of LYT-100, particularly considering the adverse event profile of current standard-of-care drugs.
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Schneider F, Stamler D, Bradbury MJ, Loupe PS, Gordon MF, Rabinovich-Guilatt L. The effect of potent CYP2D6 inhibition on the pharmacokinetics and safety of deutetrabenazine in healthy volunteers. Eur J Clin Pharmacol 2021; 78:11-18. [PMID: 34491372 PMCID: PMC8724172 DOI: 10.1007/s00228-021-03202-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 08/12/2021] [Indexed: 11/05/2022]
Abstract
Purpose Deutetrabenazine is a deuterated form of tetrabenazine with a confirmed lower rate of CYP2D6 metabolism of the active metabolites, α- and β-HTBZ. In this study, we assessed the effect of paroxetine, a potent CYP2D6 inhibitor, on the pharmacokinetics and safety of deutetrabenazine and its metabolites. Methods In this open-label sequential drug-drug-interaction study, 24 healthy adults who were CYP2D6 extensive or intermediate metabolizers received a single deutetrabenazine 22.5-mg oral dose on days 1 and 11 and a single paroxetine 20-mg oral daily dose on days 4–12. Pharmacokinetics of deutetrabenazine and its metabolites were assessed on days 1–4 and 11–14. Paroxetine trough concentrations were obtained pre-dose on days 9–13. Safety examinations occurred throughout the study. Results Paroxetine administered under steady-state conditions, increased exposure of the deuterated active metabolites, α-HTBZ (1.2-fold Cmax and 1.8-fold AUC0–∞) and β-HTBZ (2.1-fold Cmax and 5.6-fold AUC0–∞), and correspondingly, 1.6-fold Cmax and threefold AUC0–∞ for total (α + β)-HTBZ. Sixteen subjects reported 45 adverse events and most were mild. Headache was the most common AE reported 8 times by 7 subjects (5 following paroxetine alone; 2 following deutetrabenazine + paroxetine). Conclusions Paroxetine-induced increases in exposure to the active deutetrabenazine metabolites were less than those previously reported for tetrabenazine, a finding expected to reduce the burden of drug interaction. In addition, single doses of 22.5 mg deutetrabenazine, when given alone or in the presence of steady-state paroxetine (20 mg daily), were safe. Supplementary information The online version contains supplementary material available at 10.1007/s00228-021-03202-0.
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Affiliation(s)
- F Schneider
- Teva Pharmaceutical Industries Ltd, Ratiopharm GmbH, Ulm, Germany.
| | - D Stamler
- Formerly of Teva Pharmaceutical Industries Ltd, Currently Alterity Therapeutics Limited, Newark, CA, USA
| | - M J Bradbury
- Formerly of Teva Pharmaceutical Industries Ltd, Currently Alterity Therapeutics Limited, Newark, CA, USA
| | - P S Loupe
- Teva Pharmaceutical Industries Ltd, West Chester, PA, USA
| | - M F Gordon
- Teva Pharmaceutical Industries Ltd, West Chester, PA, USA
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Gajula SNR, Nadimpalli N, Sonti R. Drug metabolic stability in early drug discovery to develop potential lead compounds. Drug Metab Rev 2021; 53:459-477. [PMID: 34406889 DOI: 10.1080/03602532.2021.1970178] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Knowledge of the metabolic stability of a new drug substance eliminated by biotransformation is essential for envisaging the pharmacokinetic parameters required for deciding drug dosing and frequency. Strategies aimed at modifying lead compounds may improve metabolic stability, thereby reducing the drug dosing frequency. Replacement of selective hydrogens with deuterium can effectively enhance the drug's metabolic stability by increasing the biological half-life. Further, cyclization, change in ring size, and chirality can substantially improve the metabolic stability of drugs. The microsomal t1/2 approach for measuring drug in vitro intrinsic clearance by automated LC-MS/MS offers sensitive high-throughput screens with reliable data. The obtained in vitro intrinsic clearance from metabolic stability data helps predict the drug's in vivo total clearance using different scaling factors and hepatic clearance models. This review summarizes all the recent approaches and technological advancements in metabolic stability studies for narrowing down the potential lead compounds in drug discovery. Further, we summarized the potential pitfalls and assumptions made during the in vivo intrinsic clearance estimation from in vitro intrinsic clearance.
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Affiliation(s)
- Siva Nageswara Rao Gajula
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Nimisha Nadimpalli
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Rajesh Sonti
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
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Kinetic isotope effects and synthetic strategies for deuterated carbon-11 and fluorine-18 labelled PET radiopharmaceuticals. Nucl Med Biol 2021; 96-97:112-147. [PMID: 33892374 DOI: 10.1016/j.nucmedbio.2021.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/19/2021] [Accepted: 03/30/2021] [Indexed: 11/22/2022]
Abstract
The deuterium labelling of pharmaceuticals is a useful strategy for altering pharmacokinetic properties, particularly for improving metabolic resistance. The pharmacological effects of such metabolites are often assumed to be negligible during standard drug discovery and are factored in later at the clinical phases of development, where the risks and benefits of the treatment and side-effects can be wholly assessed. This paradigm does not translate to the discovery of radiopharmaceuticals, however, as the confounding effects of radiometabolites can inevitably show in preliminary positron emission tomography (PET) scans and thus complicate interpretation. Consequently, the formation of radiometabolites is crucial to take into consideration, compared to non-radioactive metabolites, and the application of deuterium labelling is a particularly attractive approach to minimise radiometabolite formation. Herein, we provide a comprehensive overview of the deuterated carbon-11 and fluorine-18 radiopharmaceuticals employed in PET imaging experiments. Specifically, we explore six categories of deuterated radiopharmaceuticals used to investigate the activities of monoamine oxygenase (MAO), choline, translocator protein (TSPO), vesicular monoamine transporter 2 (VMAT2), neurotransmission and the diagnosis of Alzheimer's disease; from which we derive four prominent deuteration strategies giving rise to a kinetic isotope effect (KIE) for reducing the rate of metabolism. Synthetic approaches for over thirty of these deuterated radiopharmaceuticals are discussed from the perspective of deuterium and radioisotope incorporation, alongside an evaluation of the deuterium labelling and radiolabelling efficacies across these independent studies. Clinical and manufacturing implications are also discussed to provide a more comprehensive overview of how deuterated radiopharmaceuticals may be introduced to routine practice.
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Schneider F, Stamler D, Bradbury M, Loupe PS, Hellriegel E, Cox DS, Savola JM, Gordon MF, Rabinovich-Guilatt L. Pharmacokinetics of Deutetrabenazine and Tetrabenazine: Dose Proportionality and Food Effect. Clin Pharmacol Drug Dev 2020; 10:647-659. [PMID: 33038289 PMCID: PMC8246815 DOI: 10.1002/cpdd.882] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/08/2020] [Accepted: 09/15/2020] [Indexed: 01/02/2023]
Abstract
Deutetrabenazine (Austedo, Teva), an approved treatment of chorea in Huntington's disease and tardive dyskinesia in adult patients, is a rationally designed deuterated form of tetrabenazine. Two studies assessed the pharmacokinetics and safety of deutetrabenazine compared with tetrabenazine, and the effects of food on absorption of the deuterated active metabolites, α‐dihydrotetrabenazine (α‐HTBZ) and β‐dihydrotetrabenazine (β‐HTBZ). One study was an open‐label 2‐part study in healthy volunteers; the first part included a crossover single dose of two 15 mg candidate deutetrabenazine formulations in fed and fasted states compared with tetrabenazine 25 mg in the fasted state, and the second part included single and repeated dosing of the commercial formulation of deutetrabenazine (7.5, 15, and 22.5 mg) compared with tetrabenazine 25 mg. The second study was an open‐label 5‐way crossover study in healthy volunteers (n = 32) to evaluate relative bioavailability of 4 dose levels of the commercial formulation of deutetrabenazine (6, 12, 18, and 24 mg) with a standard meal and 18 mg with a high‐fat meal. Both studies confirmed longer half‐lives for active metabolites and lower peak‐to‐trough fluctuations for the sum of the metabolites (total [α+β]‐HTBZ) following deutetrabenazine compared with tetrabenazine (3‐ to 4‐fold and 11‐fold, respectively) in steady‐state conditions. Deutetrabenazine doses estimated to provide total (α+β)‐HTBZ exposure comparable to tetrabenazine 25 mg were 11.4‐13.2 mg. Food had no effect on exposure to total (α+β)‐HTBZ, as measured by AUC. Although the total (α+β)‐HTBZ Cmax of deutetrabenazine was increased by ≈50% in the presence of food, it remained lower than that of tetrabenazine.
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Affiliation(s)
- Frank Schneider
- Teva Pharmaceutical Industries Ltd, Ratiopharm GmbH, Ulm, Germany
| | - David Stamler
- Formerly of Teva Pharmaceutical Industries Ltd, currently Alterity Therapeutics Limited, Newark, California, USA
| | - Margaret Bradbury
- Formerly of Teva Pharmaceutical Industries Ltd, currently Alterity Therapeutics Limited, Newark, California, USA
| | - Pippa S Loupe
- Teva Pharmaceutical Industries Ltd, West Chester, Pennsylvania, USA
| | - Edward Hellriegel
- Formerly of Teva Pharmaceuticals Ltd, currently Aclaris Therapeutics Inc., Wayne, Pennsylvania, USA
| | - Donna S Cox
- Formerly of Teva Pharmaceuticals Ltd, currently Pfizer Corporation, Norristown, Pennsylvania, USA
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