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Whiteley LO. An Overview of Nonclinical and Clinical Liver Toxicity Associated With AAV Gene Therapy. Toxicol Pathol 2023; 51:400-404. [PMID: 37772805 DOI: 10.1177/01926233231201408] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
This article reviews the presentation given at the 2023 annual meeting of the Society of Toxicologic Pathology (STP) on liver toxicity observed with adeno-associated viral vector (AAV) gene therapy. After decades as a therapeutic modality largely confined to the academic research environment, gene therapy has emerged in recent years as a rapidly expanding therapeutic approach in the biopharmaceutical industry with AAV as the most commonly used viral vector for gene delivery. This interest in the field of gene therapy by industry has been enhanced by the recent success of approved therapies for curing genetic diseases such as ZOLGENSMA for spinal muscular atrophy and LUXTURNA for Leber congenital amaurosis. However, recently reported clinical and nonclinical toxicities highlight the challenges in safely developing AAV gene therapies that require high dose systemic administration. The presentation reviewed general attributes of AAV as a gene therapy vector, clinical and nonclinical liver toxicity associated with AAV gene therapy and the potential for a multimodal immune suppression strategy that may mitigate toxicities.
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Bangari DS, Lanigan LG, Cramer SD, Grieves JL, Meisner R, Rogers AB, Galbreath EJ, Bolon B. Toxicologic Neuropathology of Novel Biotherapeutics. Toxicol Pathol 2023; 51:414-431. [PMID: 38380881 DOI: 10.1177/01926233241230542] [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] [Indexed: 02/22/2024]
Abstract
Biotherapeutic modalities such as cell therapies, gene therapies, nucleic acids, and proteins are increasingly investigated as disease-modifying treatments for severe and life-threatening neurodegenerative disorders. Such diverse bio-derived test articles are fraught with unique and often unpredictable biological consequences, while guidance regarding nonclinical experimental design, neuropathology evaluation, and interpretation is often limited. This paper summarizes key messages offered during a half-day continuing education course on toxicologic neuropathology of neuro-targeted biotherapeutics. Topics included fundamental neurobiology concepts, pharmacology, frequent toxicological findings, and their interpretation including adversity decisions. Covered biotherapeutic classes included cell therapies, gene editing and gene therapy vectors, nucleic acids, and proteins. If agents are administered directly into the central nervous system, initial screening using hematoxylin and eosin (H&E)-stained sections of currently recommended neural organs (brain [7 levels], spinal cord [3 levels], and sciatic nerve) may need to expand to include other components (e.g., more brain levels, ganglia, and/or additional nerves) and/or special neurohistological procedures to characterize possible neural effects (e.g., cell type-specific markers for reactive glial cells). Scientists who evaluate the safety of novel biologics will find this paper to be a practical reference for preclinical safety testing and risk assessment.
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Affiliation(s)
| | | | | | | | - René Meisner
- Denali Therapeutics, South San Francisco, California, USA
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Bennet BM, Pardo ID, Assaf BT, Buza E, Cramer SD, Crawford LK, Engelhardt JA, Galbreath EJ, Grubor B, Morrison JP, Osborne TS, Sharma AK, Bolon B. Scientific and Regulatory Policy Committee Technical Review: Biology and Pathology of Ganglia in Animal Species Used for Nonclinical Safety Testing. Toxicol Pathol 2023; 51:278-305. [PMID: 38047294 DOI: 10.1177/01926233231213851] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Dorsal root ganglia (DRG), trigeminal ganglia (TG), other sensory ganglia, and autonomic ganglia may be injured by some test article classes, including anti-neoplastic chemotherapeutics, adeno-associated virus-based gene therapies, antisense oligonucleotides, nerve growth factor inhibitors, and aminoglycoside antibiotics. This article reviews ganglion anatomy, cytology, and pathology (emphasizing sensory ganglia) among common nonclinical species used in assessing product safety for such test articles (TAs). Principal histopathologic findings associated with sensory ganglion injury include neuron degeneration, necrosis, and/or loss; increased satellite glial cell and/or Schwann cell numbers; and leukocyte infiltration and/or inflammation. Secondary nerve fiber degeneration and/or glial reactions may occur in nerves, dorsal spinal nerve roots, spinal cord (dorsal and occasionally lateral funiculi), and sometimes the brainstem. Ganglion findings related to TA administration may result from TA exposure and/or trauma related to direct TA delivery into the central nervous system or ganglia. In some cases, TA-related effects may need to be differentiated from a spectrum of artifactual and/or spontaneous background changes.
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Affiliation(s)
| | | | | | - Elizabeth Buza
- University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | | | | | | | | | - James P Morrison
- Charles River Laboratories, Inc., Shrewsbury, Massachusetts, USA
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Bennet BM, Pardo ID, Assaf BT, Buza E, Cramer S, Crawford LK, Engelhardt JA, Grubor B, Morrison JP, Osborne TS, Sharma AK, Bolon B. Scientific and Regulatory Policy Committee Points to Consider: Sampling, Processing, Evaluation, Interpretation, and Reporting of Test Article-Related Ganglion Pathology for Nonclinical Toxicity Studies. Toxicol Pathol 2023; 51:176-204. [PMID: 37489508 DOI: 10.1177/01926233231179707] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Certain biopharmaceutical products consistently affect dorsal root ganglia, trigeminal ganglia, and/or autonomic ganglia. Product classes targeting ganglia include antineoplastic chemotherapeutics, adeno-associated virus-based gene therapies, antisense oligonucleotides, and anti-nerve growth factor agents. This article outlines "points to consider" for sample collection, processing, evaluation, interpretation, and reporting of ganglion findings; these points are consistent with published best practices for peripheral nervous system evaluation in nonclinical toxicity studies. Ganglion findings often occur as a combination of neuronal injury (e.g., degeneration, necrosis, and/or loss) and/or glial effects (e.g., increased satellite glial cell cellularity) with leukocyte accumulation (e.g., mononuclear cell infiltration or inflammation). Nerve fiber degeneration and/or glial reactions may be seen in nerves, dorsal spinal nerve roots, spinal cord, and occasionally brainstem. Interpretation of test article (TA)-associated effects may be confounded by incidental background changes or experimental procedure-related changes and limited historical control data. Reports should describe findings at these sites, any TA relationship, and the criteria used for assigning severity grades. Contextualizing adversity of ganglia findings can require a weight-of-evidence approach because morphologic changes of variable severity occur in ganglia but often are not accompanied by observable overt in-life functional alterations detectable by conventional behavioral and neurological testing techniques.
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Affiliation(s)
| | | | | | - Elizabeth Buza
- University of Pennsylvania, Gene Therapy Program, Philadelphia, Pennsylvania, USA
| | | | - LaTasha K Crawford
- University of Wisconsin-Madison, School of Veterinary Medicine, Madison, Wisconsin, USA
| | | | | | - James P Morrison
- Charles River Laboratories, Inc., Shrewsbury, Massachusetts, USA
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Baldrick P, McIntosh B, Prasad M. Adeno-associated virus (AAV)-based gene therapy products: What are toxicity studies in non-human primates showing us? Regul Toxicol Pharmacol 2023; 138:105332. [PMID: 36592683 DOI: 10.1016/j.yrtph.2022.105332] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 12/23/2022] [Accepted: 12/28/2022] [Indexed: 01/01/2023]
Abstract
A number of adeno-associated virus (AAV)-based gene therapy products have entered clinical development, with a few also reaching marketing approval. However, as our knowledge of them grows from nonclinical and clinical testing, it has become apparent that various actual and theoretical safety issues can arise from their use. This review of 19 Good Laboratory Practice (GLP)-compliant toxicity studies in non-human primates (NHPs) with AAV-based gene therapy products via a variety of different dose routes in the period 2017-2021 showed results ranging from no study findings different from controls, or findings considered to be non-adverse, to actual toxicity, with changes highlighting careful monitoring in the clinic. Similar findings were found from a review of a number of published toxicity studies in NHPs. It was confirmed that studies have a role in evaluating for dorsal root ganglion (DRG) and/or peripheral nerve toxicity, hepatotoxicity, adverse immunogenicity and, to a lesser degree, insertional mutagenesis as well as other potential unacceptable findings such as adverse inflammation for ocular therapy candidates. Overall, it was demonstrated that toxicity (and biodistribution) studies in NHPs are a vital part of the safety assessment of AAV-based gene therapy products prior to clinical entry.
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Affiliation(s)
- Paul Baldrick
- Product Development and Market Access Consulting, Clinical Development & Commercialisation Services, Labcorp Drug Development Inc. (formerly Covance), Harrogate, North Yorkshire, HG3 1PY, United Kingdom
| | - Brian McIntosh
- Cell and Gene Therapy, Safety Assessment, Toxicology, Labcorp Drug Development Inc. (formerly Covance), Madison, WI, 53704, USA.
| | - Mayuri Prasad
- Cell and Gene Therapy, Safety Assessment, Toxicology, Labcorp Drug Development Inc. (formerly Covance), Madison, WI, 53704, USA.
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Upadhyay A, Cao UMN, Hariharan A, Almansoori A, Tran SD. Gene Therapeutic Delivery to the Salivary Glands. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1436:55-68. [PMID: 36826746 DOI: 10.1007/5584_2023_766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
The salivary glands, exocrine glands in our body producing saliva, can be easily damaged by various factors. Radiation therapy and Sjogren's syndrome (a systemic autoimmune disease) are the two main causes of salivary gland damage, leading to a severe reduction in patients' quality of life. Gene transfer to the salivary glands has been considered a promising approach to treating the dysfunction. Gene therapy has long been applied to cure multiple diseases, including cancers, and hereditary and infectious diseases, which are proven to be safe and effective for the well-being of patients. The application of this treatment on salivary gland injuries has been studied for decades, yet its clinical progress is delayed. This chapter provides a coup d'oeil into gene transfer methods and various gene/vector types for salivary glands to help the new scientists and update established scientists on the progress that has been made during the past decades for the treatment of salivary gland disorders.
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Affiliation(s)
- Akshaya Upadhyay
- McGill Craniofacial Tissue Engineering and Stem Cells Laboratory, Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada
| | - Uyen M N Cao
- McGill Craniofacial Tissue Engineering and Stem Cells Laboratory, Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada
| | - Arvind Hariharan
- McGill Craniofacial Tissue Engineering and Stem Cells Laboratory, Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada
| | - Akram Almansoori
- McGill Craniofacial Tissue Engineering and Stem Cells Laboratory, Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada
| | - Simon D Tran
- McGill Craniofacial Tissue Engineering and Stem Cells Laboratory, Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada.
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Khan SU, Khan MU, Khan MI, Kalsoom F, Zahra A. Current Landscape and Emerging Opportunities of Gene Therapy with Non-viral Episomal Vectors. Curr Gene Ther 2023; 23:135-147. [PMID: 36200188 DOI: 10.2174/1566523222666221004100858] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 06/10/2022] [Accepted: 06/10/2022] [Indexed: 11/22/2022]
Abstract
Gene therapy has proven to be extremely beneficial in the management of a wide range of genetic disorders for which there are currently no or few effective treatments. Gene transfer vectors are very significant in the field of gene therapy. It is possible to attach a non-viral attachment vector to the donor cell chromosome instead of integrating it, eliminating the negative consequences of both viral and integrated vectors. It is a safe and optimal express vector for gene therapy because it does not cause any adverse effects. However, the modest cloning rate, low expression, and low clone number make it unsuitable for use in gene therapy. Since the first generation of non-viral attachment episomal vectors was constructed, various steps have been taken to regulate their expression and stability, such as truncating the MAR element, lowering the amount of CpG motifs, choosing appropriate promoters and utilizing regulatory elements. This increases the transfection effectiveness of the non-viral attachment vector while also causing it to express at a high level and maintain a high level of stability. A vector is a genetic construct commonly employed in gene therapy to treat various systemic disorders. This article examines the progress made in the development of various optimization tactics for nonviral attachment vectors and the future applications of these vectors in gene therapy.
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Affiliation(s)
- Safir Ullah Khan
- Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei 230027, People's Republic of China
| | - Munir Ullah Khan
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027 China
| | - Muhammad Imran Khan
- School of Life Sciences and Medicine, University of Science and Technology of China,Hefei 230027,People's Republic of China
- Department of Pathology, District Headquarters Hospital Jhang 35200, Punjab Province, Islamic Republic of Pakistan
| | - Fadia Kalsoom
- Department of Pathology, District Headquarters Hospital Jhang 35200, Punjab Province, Islamic Republic of Pakistan
| | - Aqeela Zahra
- Department of Family and Community Medicine. College of Medicine, University of Ha'il, Ha'il 81451, Saudi Arabia
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Meseck EK, Guibinga G, Wang S, McElroy C, Hudry E, Mansfield K. Intrathecal sc-AAV9-CB-GFP: Systemic Distribution Predominates Following Single-Dose Administration in Cynomolgus Macaques. Toxicol Pathol 2022; 50:415-431. [PMID: 35658751 PMCID: PMC9284083 DOI: 10.1177/01926233221101309] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Biodistribution of self-complementary adeno-associated virus-9 (scAAV9)–chicken β-actin
promoter–green fluorescent protein (GFP) was assessed in juvenile cynomolgus macaques
infused intrathecally via lumbar puncture or the intracisterna magna (1.0×1013
or 3.0×1013 vg/animal), with necropsy 28 days later. Our results characterized
central nervous system biodistribution compared with systemic organs/tissues by droplet
digital polymerase chain reaction for DNA and in situ hybridization.
Green fluorescent protein expression was characterized by Meso Scale Discovery
electrochemiluminescence immunosorbent assay and immunohistochemistry (IHC).
Biodistribution was widespread but variable, with vector DNA and GFP expression greatest
in the spinal cord, dorsal root ganglia (DRG), and certain systemic tissues (e.g., liver),
with low concentrations in many brain regions despite direct cerebrospinal fluid
administration. Transduction and expression were observed primarily in perivascular
astrocytes in the brain, with a paucity in neurons. Greater GFP expression was observed in
hepatocytes, striated myocytes, cardiomyocytes, spinal cord lower motor neurons, and DRG
sensory neurons by IHC. These results should be considered when evaluating scAAV9-based
intrathecal delivery with the current expression cassette as a modality for neurologic
diseases that require widespread brain neuronal expression. This capsid/expression
cassette combination may be better suited for diseases that express a secreted protein
and/or do not require widespread brain neuronal transduction.
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Affiliation(s)
- Emily K Meseck
- Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, USA
| | - Ghiabe Guibinga
- Novartis Institutes for BioMedical Research Biologics Center, San Diego, California, USA
| | - Stephen Wang
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA
| | - Cameron McElroy
- Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, USA
| | - Eloise Hudry
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA
| | - Keith Mansfield
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA
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Abstract
PURPOSE OF REVIEW Although the basic treatment of congenital adrenal hyperplasia (CAH) is well established, there are active clinical research projects to more closely mimic the normal diurnal rhythm of cortisol secretion and to reduce total glucocorticoid doses to minimize adverse metabolic effects. RECENT FINDINGS We review clinical studies on CAH treatment published in the last 18 months or currently underway according to ClinicalTrials.gov listings. These can be grouped into several broad themes: alternative dosing forms of hydrocortisone with altered pharmacokinetics or easier dose titration; corticotropin-releasing hormone receptor antagonists that reduce corticotropin (ACTH) secretion and thereby reduce adrenal androgen secretion; androgen biosynthesis inhibitors; a first clinical trial of a gene therapy vector. SUMMARY Alternative dosing forms of hydrocortisone are, or will shortly be, marketed, but cost may be a barrier to utilization, at least in the US market. Trials of corticotropin releasing hormone receptor antagonists and androgen biosynthesis inhibitors are currently underway. The author believes that trials of gene therapy for CAH are premature.
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Affiliation(s)
- Perrin C White
- UT Southwestern Medical Center, Professor of Pediatrics, Dallas, Texas, USA
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Zhang Y, Qian L, Kuang Y, Liu J, Wang D, Xie W, Zhang L, Fu L. An adeno-associated virus-mediated immunotherapy for Alzheimer’s disease. Mol Immunol 2022; 144:26-34. [DOI: 10.1016/j.molimm.2022.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 01/30/2022] [Accepted: 02/06/2022] [Indexed: 11/29/2022]
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