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Tasdighi E, Adhikari R, Almaadawy O, Leucker TM, Blaha MJ. LP(a): Structure, Genetics, Associated Cardiovascular Risk, and Emerging Therapeutics. Annu Rev Pharmacol Toxicol 2024; 64:135-157. [PMID: 37506332 DOI: 10.1146/annurev-pharmtox-031023-100609] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Lipoprotein(a) [Lp(a)] is a molecule bound to apolipoprotein(a) with some similarity to low-density lipoprotein cholesterol (LDL-C), which has been found to be a risk factor for cardiovascular disease (CVD). Lp(a) appears to induce inflammation, atherogenesis, and thrombosis. Approximately 20% of the world's population has increased Lp(a) levels, determined predominantly by genetics. Current clinical practices for the management of dyslipidemia are ineffective in lowering Lp(a) levels. Evolving RNA-based therapeutics, such as the antisense oligonucleotide pelacarsen and small interfering RNA olpasiran, have shown promising results in reducing Lp(a) levels. Phase III pivotal cardiovascular outcome trials [Lp(a)HORIZON and OCEAN(a)] are ongoing to evaluate their efficacy in secondary prevention of major cardiovascular events in patients with elevated Lp(a). The future of cardiovascular residual risk reduction may transition to a personalized approach where further lowering of either LDL-C, triglycerides, or Lp(a) is selected after high-intensity statin therapy based on the individual risk profile and preferences of each patient.
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Affiliation(s)
- Erfan Tasdighi
- Ciccarone Center for the Prevention of Cardiovascular Disease, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA;
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Rishav Adhikari
- Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Omar Almaadawy
- Department of Medicine, MedStar Union Memorial Hospital, Baltimore, Maryland, USA
| | - Thorsten M Leucker
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Michael J Blaha
- Ciccarone Center for the Prevention of Cardiovascular Disease, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA;
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Ayyar VS, Song D. Mechanistic Pharmacokinetics and Pharmacodynamics of GalNAc-siRNA: Translational Model Involving Competitive Receptor-Mediated Disposition and RISC-Dependent Gene Silencing Applied to Givosiran. J Pharm Sci 2024; 113:176-190. [PMID: 37871778 DOI: 10.1016/j.xphs.2023.10.026] [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: 09/21/2023] [Revised: 10/18/2023] [Accepted: 10/18/2023] [Indexed: 10/25/2023]
Abstract
Triantennary N-acetyl-D galactosamine (GalNAc)3-conjugated small interfering RNA (siRNA) have majorly advanced the development of RNA-based therapeutics. Chemically stabilized GalNAc-siRNAs exhibit extensive albeit capacity-limited (nonlinear) distribution into hepatocytes with additional complexities in intracellular liver disposition and pharmacology. A mechanism-based pharmacokinetic-pharmacodynamic (PK-PD) model of GalNAc-siRNA was developed to i) quantitate ASGPR-mediated disposition and downstream RNA-induced silencing complex (RISC)-dependent pharmacology following intravenous (IV) and subcutaneous (SC) dosing, ii) assess the kinetics of formed active metabolite, iii) leverage, as an example, published experimental data for givosiran, and iv) demonstrate PK translation across two preclinical species (rat and monkey) with subsequent prediction of human plasma PK. The structural model is based on competition between parent and formed active metabolite for occupancy and uptake via ASGPR into hepatocytes, intracellular sequestration and degradation, and downstream engagement of RNA-induced silencing complex (RISC) governing target mRNA degradation. The model jointly and accurately captured available concentration-time profiles of givosiran and/or AS(N-1)3' givosiran in rat and/or monkey plasma, liver, and/or kidney following givosiran administered both IV and SC. RISC-dependent gene silencing of ALAS1 mRNA was well-characterized. The model estimated an in vivo affinity (KD) value of 27.7 nM for GalNAc-ASGPR and weight-based allometric exponents of -0.27 and -0.24 for SC absorption and intracellular (endolysosomal) degradation rate constants. The model well-predicted reported givosiran plasma PK profiles in humans. PK simulations revealed net-shifts in liver-to-kidney distribution ratios with increasing IV and SC dose. Importantly, decreases in the relative liver uptake efficiency were demonstrated following IV and, to a lesser extent, following SC dosing explained by differential ASGPR occupancy profiles over time.
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Affiliation(s)
- Vivaswath S Ayyar
- Clinical Pharmacology & Pharmacometrics, Janssen Research and Development, Spring House, PA, USA.
| | - Dawei Song
- Clinical Pharmacology & Pharmacometrics, Janssen Research and Development, Spring House, PA, USA
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Sosnowska B, Surma S, Banach M. Targeted Treatment against Lipoprotein (a): The Coming Breakthrough in Lipid Lowering Therapy. Pharmaceuticals (Basel) 2022; 15:ph15121573. [PMID: 36559024 PMCID: PMC9781646 DOI: 10.3390/ph15121573] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/06/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Atherosclerotic cardiovascular diseases (ASCVD) are a very important cause of premature death. The most important risk factor for ASCVD is lipid disorders. The incidence of lipid disorders and ASCVD is constantly increasing, which means that new methods of prevention and treatment of these diseases are still being searched for. In the management of patients with lipid disorders, the primary goal of therapy is to lower the serum LDL-C concentration. Despite the available effective lipid-lowering therapies, the risk of ASCVD is still increased in some patients. A high level of serum lipoprotein (a) (Lp(a)) is a risk factor for ASCVD independent of serum LDL-C concentration. About 20% of Europeans have elevated serum Lp(a) levels, requiring treatment to reduce serum Lp(a) concentrations in addition to LDL-C. Currently available lipid lowering drugs do not sufficiently reduce serum Lp(a) levels. Hence, drugs based on RNA technology, such as pelacarsen, olpasiran, SLN360 and LY3819469, are undergoing clinical trials. These drugs are very effective in lowering the serum Lp(a) concentration and have a satisfactory safety profile, which means that in the near future they will fill an important gap in the armamentarium of lipid-lowering drugs.
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Affiliation(s)
- Bożena Sosnowska
- Department of Preventive Cardiology and Lipidology, Medical University of Lodz, 93-338 Lodz, Poland
| | - Stanisław Surma
- Faculty of Medical Sciences in Katowice, Medical University of Silesia, 40-752 Katowice, Poland
| | - Maciej Banach
- Department of Preventive Cardiology and Lipidology, Medical University of Lodz, 93-338 Lodz, Poland
- Cardiovascular Research Centre, University of Zielona Gora, 65-417 Zielona Gora, Poland
- Department of Cardiology and Adult Congenital Heart Diseases, Polish Mother’s Memorial Hospital Research Institute (PMMHRI), 93-338 Lodz, Poland
- Correspondence:
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Rose RH, Sepp A, Stader F, Gill KL, Liu C, Gardner I. Application of physiologically-based pharmacokinetic models for therapeutic proteins and other novel modalities. Xenobiotica 2022; 52:840-854. [PMID: 36214113 DOI: 10.1080/00498254.2022.2133649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The past two decades have seen diversification of drug development pipelines and approvals from traditional small molecule therapies to alternative modalities including monoclonal antibodies, engineered proteins, antibody drug conjugates (ADCs), oligonucleotides and gene therapies. At the same time, physiologically-based pharmacokinetic (PBPK) models for small molecules have seen increased industry and regulatory acceptance.This review focusses on the current status of the application of PBPK models to these newer modalities and give a perspective on the successes, challenges and future directions of this field.There is greatest experience in the development of PBPK models for therapeutic proteins, and PBPK models for ADCs benefit from prior experience for both therapeutic proteins and small molecules. For other modalities, the application of PBPK models is in its infancy.Challenges are discussed and a common theme is lack of availability of physiological and experimental data to characterise systems and drug parameters to enable a priori prediction of pharmacokinetics. Furthermore, sufficient clinical data are required to build confidence in developed models.The PBPK modelling approach provides a quantitative framework for integrating knowledge and data from multiple sources and can be built on as more data becomes available.
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Affiliation(s)
- Rachel H Rose
- Certara UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Armin Sepp
- Certara UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Felix Stader
- Certara UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Katherine L Gill
- Certara UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Cong Liu
- Certara UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Iain Gardner
- Certara UK Limited, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
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Pharmacokinetic and Pharmacodynamic Modeling of siRNA Therapeutics - a Minireview. Pharm Res 2022; 39:1749-1759. [PMID: 35819583 DOI: 10.1007/s11095-022-03333-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/04/2022] [Indexed: 10/17/2022]
Abstract
The approval of four small interfering RNA (siRNA) products in the past few years has demonstrated unequivocally the therapeutic potential of this novel modality. Three such products (givosiran, lumasiran and inclisiran) are liver-targeted, using tris N-acetylgalactosamine (GalNAc)3 as the targeting ligand. Upon subcutaneous administration, GalNAc-conjugated siRNAs rapidly distribute into the liver via asialoglycoprotein receptor (ASGPR) mediated uptake in the hepatocytes, resulting in fast elimination from the systemic circulation. Patisiran, on the other hand, has been formulated in a lipid nanoparticle for optimal delivery to the liver. While several publications have described preclinical and clinical pharmacokinetic (PK) and pharmacodynamic (PD) results, including absorption, distribution, metabolism, and elimination (ADME) profiles in selected species as well as limited modeling efforts for siRNA therapeutics, there is no systematic review of the PK and PD models developed for these agents or work summarizing the utility and application(s) of such models in drug development and regulatory review. Here, we provide a mini-review of the current state of modeling efforts for siRNA therapeutics within the early preclinical, translational, and clinical stages of siRNA development. Diverse modeling methods including simple compartmental, mechanistic and systems PK/PD, physiologically-based PK (PBPK), population PK/PD, and dose-response-time models are introduced and reviewed. The utility of such models in development and regulatory review for siRNA therapeutics is also discussed with examples. Finally, the current knowledge gaps in mechanism of action of siRNA and resulting challenges in model development are summarized. The goal of this minireview is to trigger cross-functional discussion amongst all key stakeholders to generate key experimental datasets and align on current assumptions, model structures, and approaches to facilitate development and application of robust PK/PD models for siRNA therapeutics.
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Blom DJ, Marais AD, Moodley R, van der Merwe N, van Tonder A, Raal FJ. RNA-based therapy in the management of lipid disorders: a review. Lipids Health Dis 2022; 21:41. [PMID: 35459248 PMCID: PMC9034497 DOI: 10.1186/s12944-022-01649-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/31/2022] [Indexed: 11/10/2022] Open
Abstract
This review focuses on antisense oligonucleotides and small interfering ribonucleic acid therapies approved or under development for the management of lipid disorders. Recent advances in RNA-based therapeutics allow tissue-specific targeting improving safety. Multiple potential target proteins have been identified and RNA-based therapeutics have the potential to significantly improve outcomes for patients with or at risk for atherosclerotic cardiovascular disease. The advantages of RNA-based lipid modifying therapies include the ability to reduce the concentration of almost any target protein highly selectively, allowing for more precise control of metabolic pathways than can often be achieved with small molecule-based drugs. RNA-based lipid modifying therapies also make it possible to reduce the expression of target proteins for which there are no small molecule inhibitors. RNA-based therapies can also reduce pill burden as their administration schedule typically varies from weekly to twice yearly injections. The safety profile of most current RNA-based lipid therapies is acceptable but adverse events associated with various therapies targeting lipid pathways have included injection site reactions, inflammatory reactions, hepatic steatosis and thrombocytopenia. While the body of evidence for these therapies is expanding, clinical experience with these therapies is currently limited in duration and the results of long-term studies are eagerly awaited.
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Affiliation(s)
- Dirk Jacobus Blom
- Department of Medicine, Division of Lipidology and Hatter Institute for Cardiovascular Research in Africa, University of Cape Town, Cape Town, South Africa.
| | - Adrian David Marais
- Division of Chemical Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Rajen Moodley
- Netcare Umhlanga Medical Center, Umhlanga, KwaZulu Natal, South Africa
| | | | | | - Frederick Johan Raal
- Carbohydrate and Lipid Metabolism Research Unit, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa
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Ayyar VS, Song D, Zheng S, Carpenter T, Heald DL. Minimal Physiologically Based Pharmacokinetic-Pharmacodynamic (mPBPK-PD) Model of N-Acetylgalactosamine-Conjugated Small Interfering RNA Disposition and Gene Silencing in Preclinical Species and Humans. J Pharmacol Exp Ther 2021; 379:134-146. [PMID: 34413198 DOI: 10.1124/jpet.121.000805] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/16/2021] [Indexed: 12/20/2022] Open
Abstract
Conjugation of small interfering RNA (siRNA) to tris N-acetylgalactosamine [(GalNAc)3] can enable highly selective, potent, and durable knockdown of targeted proteins in the liver. However, potential knowledge gaps between in vitro experiments, preclinical species, and clinical scenarios remain. A minimal physiologically based pharmacokinetic-pharmacodynamic model for GalNAc-conjugated siRNA (GalNAc-siRNA) was developed using published data for fitusiran (ALN-AT3), an investigational compound targeting liver antithrombin (AT), to delineate putative determinants governing the whole-body-to-cellular pharmacokinetic (PK) and pharmacodynamic (PD) properties of GalNAc-siRNA and facilitate preclinical-to-clinical translation. The model mathematically linked relevant mechanisms: 1) hepatic biodistribution, 2) tris-GalNAc binding to asialoglycoprotein receptors (ASGPRs) on hepatocytes, 3) ASGPR endocytosis and recycling, 4) endosomal transport and escape of siRNA, 5) cytoplasmic RNA-induced silencing complex (RISC) loading, 6) degradation of target mRNA by bound RISC, and 7) knockdown of protein. Physiologic values for 36 out of 48 model parameters were obtained from the literature. Kinetic parameters governing (GalNAc)3-ASGPR binding and internalization were derived from published studies of uptake in hepatocytes. The proposed model well characterized reported pharmacokinetics, RISC dynamics, and knockdown of AT mRNA and protein by ALN-AT3 in mice. The model bridged multiple PK-PD data sets in preclinical species (mice, rat, monkey) and successfully captured reported plasma pharmacokinetics and AT knockdown in a phase I ascending-dose study. Estimates of in vivo potency were similar (∼2-fold) across species. Subcutaneous absorption and serum AT degradation rate constants scaled across species by body weight with allometric exponents of -0.29 and -0.22. The proposed mechanistic modeling framework characterizes the unique PK-PD properties of GalNAc-siRNA. SIGNIFICANCE STATEMENT: Tris N-acetylgalactosamine (GalNAc)3-conjugated small interfering RNA (siRNA) therapeutics enable liver-targeted gene therapy and precision medicine. Using a translational and systems-based minimal physiologically based pharmacokinetic-pharmacodynamic (mPBPK-PD) modeling approach, putative determinants influencing GalNAc-conjugated siRNA (GalNAc-siRNA) functionality in three preclinical species and humans were investigated. The developed model successfully integrated and characterized relevant published in vitro-derived biomeasures, mechanistic PK-PD profiles in animals, and observed clinical PK-PD responses for an investigational GalNAc-siRNA (fitusiran). This modeling effort delineates the disposition and liver-targeted pharmacodynamics of GalNAc-siRNA.
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Affiliation(s)
- Vivaswath S Ayyar
- Clinical Pharmacology & Pharmacometrics (V.S.A., D.S.) and Janssen BioTherapeutics (V.S.A., S.Z., T.C., D.L.H.), Janssen Research and Development, Spring House, Pennsylvania
| | - Dawei Song
- Clinical Pharmacology & Pharmacometrics (V.S.A., D.S.) and Janssen BioTherapeutics (V.S.A., S.Z., T.C., D.L.H.), Janssen Research and Development, Spring House, Pennsylvania
| | - Songmao Zheng
- Clinical Pharmacology & Pharmacometrics (V.S.A., D.S.) and Janssen BioTherapeutics (V.S.A., S.Z., T.C., D.L.H.), Janssen Research and Development, Spring House, Pennsylvania
| | - Thomas Carpenter
- Clinical Pharmacology & Pharmacometrics (V.S.A., D.S.) and Janssen BioTherapeutics (V.S.A., S.Z., T.C., D.L.H.), Janssen Research and Development, Spring House, Pennsylvania
| | - Donald L Heald
- Clinical Pharmacology & Pharmacometrics (V.S.A., D.S.) and Janssen BioTherapeutics (V.S.A., S.Z., T.C., D.L.H.), Janssen Research and Development, Spring House, Pennsylvania
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Willoughby JLS, Chan A, Sehgal A, Butler JS, Nair JK, Racie T, Shulga-Morskaya S, Nguyen T, Qian K, Yucius K, Charisse K, van Berkel TJC, Manoharan M, Rajeev KG, Maier MA, Jadhav V, Zimmermann TS. Evaluation of GalNAc-siRNA Conjugate Activity in Pre-clinical Animal Models with Reduced Asialoglycoprotein Receptor Expression. Mol Ther 2017; 26:105-114. [PMID: 28988716 PMCID: PMC5762979 DOI: 10.1016/j.ymthe.2017.08.019] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/21/2017] [Accepted: 08/24/2017] [Indexed: 02/04/2023] Open
Abstract
The hepatocyte-specific asialoglycoprotein receptor (ASGPR) is an ideal candidate for targeted drug delivery to the liver due to its high capacity for substrate clearance from circulation together with its well-conserved expression and function across species. The development of GalNAc-siRNA conjugates, in which a synthetic triantennary N-acetylgalactosamine-based ligand is conjugated to chemically modified siRNA, has enabled efficient, ASGPR-mediated delivery to hepatocytes. To investigate the potential impact of variations in receptor expression on the efficiency of GalNAc-siRNA conjugate delivery, we evaluated the pharmacokinetics and pharmacodynamics of GalNAc-siRNA conjugates in multiple pre-clinical models with reduced receptor expression. Despite greater than 50% reduction in ASGPR levels, GalNAc conjugate activity was retained, suggesting that the remaining receptor capacity was sufficient to mediate efficient uptake of potent GalNAc-siRNAs at pharmacologically relevant dose levels. Collectively, our data support a broad application of the GalNAc-siRNA technology for hepatic targeting, including disease states where ASGPR expression may be reduced.
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Affiliation(s)
| | - Amy Chan
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Alfica Sehgal
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | - Tim Racie
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | - Tuyen Nguyen
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Kun Qian
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | - Theo J C van Berkel
- Division of Biopharmaceutics, Leiden Academic Center for Drug Research, 2300 RA Leiden, the Netherlands
| | | | | | | | - Vasant Jadhav
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
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Ha Y, Choi HK. Recent conjugation strategies of small organic fluorophores and ligands for cancer-specific bioimaging. Chem Biol Interact 2016; 248:36-51. [DOI: 10.1016/j.cbi.2016.02.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 02/02/2016] [Accepted: 02/08/2016] [Indexed: 01/03/2023]
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Mamidyala SK, Dutta S, Chrunyk BA, Préville C, Wang H, Withka JM, McColl A, Subashi TA, Hawrylik SJ, Griffor MC, Kim S, Pfefferkorn JA, Price DA, Menhaji-Klotz E, Mascitti V, Finn M. Glycomimetic Ligands for the Human Asialoglycoprotein Receptor. J Am Chem Soc 2012; 134:1978-81. [DOI: 10.1021/ja2104679] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sreeman K. Mamidyala
- Department
of Chemistry, The Scripps Research Institute, 10550 North Torrey
Pines Road, La Jolla, California 92037, United States
| | - Sanjay Dutta
- Department
of Chemistry, The Scripps Research Institute, 10550 North Torrey
Pines Road, La Jolla, California 92037, United States
| | - Boris A. Chrunyk
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Cathy Préville
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Hong Wang
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Jane M. Withka
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Alexander McColl
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Timothy A. Subashi
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Steven J. Hawrylik
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Matthew C. Griffor
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Sung Kim
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Jeffrey A. Pfefferkorn
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - David A. Price
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Elnaz Menhaji-Klotz
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - Vincent Mascitti
- Pfizer Global Research & Development, Eastern Point Road, Groton, Connecticut 06340, United States
| | - M.G. Finn
- Department
of Chemistry, The Scripps Research Institute, 10550 North Torrey
Pines Road, La Jolla, California 92037, United States
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Yuan L, Wang J, Shen WC. Reversible lipidization of somatostatin analogues for the liver targeting. Eur J Pharm Biopharm 2008; 70:615-20. [PMID: 18614343 DOI: 10.1016/j.ejpb.2008.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2007] [Revised: 04/30/2008] [Accepted: 05/05/2008] [Indexed: 10/22/2022]
Abstract
Tyr(3)-octreotide (TOC), a somatostatin analogue, is reversibly lipidized for passive delivery to the liver with the aim of increasing its association with hepatocytes. The reversibly lipidized TOC (REAL-TOC) was formed by the conjugation of the N-palmitoyl cysteinyl moiety to the cysteinyl residues of reduced TOC through disulfide linkages and characterized by matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF) analysis. The measured mass of REAL-TOC (M+H)(+) is 1752.31 Da (calculated mass: 1752.78), confirming that two molecules of N-palmitoyl cysteines are linked to TOC via disulfide bonds. TOC and REAL-TOC were radioiodinated and administered to mice. Their biodistribution and intrahepatic distribution were subsequently investigated. The area under the curve (AUC) of (125)I-REAL-TOC in the liver was 3.8-fold greater than that of (125)I-TOC, with 20.5% and 5.8% of the injected dose (ID)/g of (125)I-REAL-TOC remaining in the liver at 2 and 24h post injection, respectively. Within the liver, TOC was primarily distributed to parenchymal cells (PC). Nevertheless, TOC was quickly excreted out and only 2.4% ID per 100mg protein remained in the PC at 2h post injection. (125)I-REAL-TOC was retained in PC for up to 2h with a constant concentration of around 6% ID/100mg protein. (125)I-REAL-TOC was also highly associated with nonparenchymal cells (NPC) at significantly higher levels than (125)I-TOC at 10min, 1h and 2h post injection. Since somatostatin analogues have been evaluated for treating late-stage hepatocellular carcinoma (HCC), the reversibly lipidized conjugates may possess enhanced therapeutic efficacy due to the liver-targeting effect.
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Affiliation(s)
- Liyun Yuan
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 90089, USA
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