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Mackall CL, Bollard CM, Goodman N, Carr C, Gardner R, Rouce R, Sotillo E, Stoner R, Urnov FD, Wayne AS, Park J, Kohn DB. Enhancing pediatric access to cell and gene therapies. Nat Med 2024; 30:1836-1846. [PMID: 38886624 DOI: 10.1038/s41591-024-03035-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/30/2024] [Indexed: 06/20/2024]
Abstract
Increasing numbers of cell and gene therapies (CGTs) are emerging to treat and cure pediatric diseases. However, small market sizes limit the potential return on investment within the traditional biopharmaceutical drug development model, leading to a market failure. In this Perspective, we discuss major factors contributing to this failure, including high manufacturing costs, regulatory challenges, and licensing practices that do not incorporate pediatric development milestones, as well as potential solutions. We propose the creation of a new entity, the Pediatric Advanced Medicines Biotech, to lead late-stage development and commercialize pediatric CGTs outside the traditional biopharmaceutical model in the United States-where organized efforts to solve this problem have been lacking. The Pediatric Advanced Medicines Biotech would partner with the academic ecosystem, manufacture products in academic good manufacturing practice facilities and work closely with regulatory bodies, to ferry CGTs across the drug development 'valley of death' and, ultimately, increase access to lifesaving treatments for children in need.
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Affiliation(s)
- Crystal L Mackall
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA.
- Department of Pediatrics, Division of Pediatric Hematology, Oncology, Stem Cell Transplant and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, USA.
- Department of Medicine, Division of Bone Marrow Transplant and Cell Therapy, Stanford University School of Medicine, Stanford, CA, USA.
| | - Catherine M Bollard
- Center for Cancer and Immunology Research and Department of Pediatrics, Children's National Hospital and The George Washington University, Washington, DC, USA
| | | | - Casey Carr
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Rayne Rouce
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston Methodist Hospital and Texas Children's Hospital, Houston, TX, USA
| | - Elena Sotillo
- Center for Cancer Cell Therapy, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Fyodor D Urnov
- Innovative Genomics Institute, University of California at Berkeley, Berkeley, CA, USA
| | - Alan S Wayne
- Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Julie Park
- St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Donald B Kohn
- Departments of Microbiology, Immunology & Molecular Genetics; Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA
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Aksu Kuz C, Ning K, Hao S, Cheng F, Qiu J. Role of the membrane-associated accessory protein (MAAP) in adeno-associated virus (AAV) infection. J Virol 2024; 98:e0063324. [PMID: 38775479 PMCID: PMC11237668 DOI: 10.1128/jvi.00633-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 04/28/2024] [Indexed: 06/14/2024] Open
Abstract
Adeno-associated viruses (AAVs) package a single-stranded (ss) DNA genome of 4.7 kb in their capsid of ~20 nm in diameter. AAV replication requires co-infection of a helper virus, such as adenovirus. During the optimization of recombinant AAV production, a small viral nonstructural protein, membrane-associated accessory protein (MAAP), was identified. However, the function of the MAAP in the context of AAV infection remains unknown. Here, we investigated the expression strategy and function of the MAAP during infection of both AAV2 and AAV5 in human embryonic kidney (HEK)293 cells. We found that AAV2 MAAP2 and AAV5 MAAP5 are expressed from the capsid gene (cap)-transcribing mRNA spliced from the donor to the second splice site that encodes VP2 and VP3. Thus, this AAV cap gene transcribes a multicistronic mRNA that can be translated to four viral proteins, MAAP, VP2, AAP, and VP3 in order. In AAV2 infection, MAAP2 predominantly localized in the cytoplasm, alongside the capsid, near the nuclear and plasma membranes, but a fraction of MAAP2 exhibited nuclear localization. In AAV5 infection, MAAP5 revealed a distinct pattern, predominantly localizing within the nucleus. In the cells infected with an MAAP knockout mutant of AAV2 or AAV5, both viral DNA replication and virus replication increased, whereas virus egress decreased, and the decrease in virus egress can be restored by providing MAAP in trans. In summary, MAAP, a novel AAV nonstructural protein translated from a multicistronic viral cap mRNA, not only facilitates cellular egress of AAV but also likely negatively affects viral DNA replication during infection. IMPORTANCE Recombinant adeno-associated virus (rAAV) has been used as a gene delivery vector in clinical gene therapy. In current gene therapies employing rAAV, a high dose of the vector is required. Consequently, there is a high demand for efficient and high-purity vector production systems. In this study, we demonstrated that membrane-associated accessory protein (MAAP), a small viral nonstructural protein, is translated from the same viral mRNA transcript encoding VP2 and VP3. In AAV-infected cells, apart from its prevalent expression in the cytoplasm with localization near the plasma and nuclear membranes, the MAAP also exhibits notable localization within the nucleus. During AAV infection, MAAP expression increases the cellular egress of progeny virions and decreases viral DNA replication and progeny virion production. Thus, the choice of MAAP expression has pros and cons during AAV infection, which could provide a guide to rAAV production.
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Affiliation(s)
- Cagla Aksu Kuz
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Kang Ning
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Siyuan Hao
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Fang Cheng
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Jianming Qiu
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
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Bala NS, Thornburg CD. Gene Therapy in Hemophilia A: Achievements, Challenges, and Perspectives. Semin Thromb Hemost 2024. [PMID: 38588706 DOI: 10.1055/s-0044-1785483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
Strides in advancements of care of persons with hemophilia include development of long-acting factor replacement therapies, novel substitution and hemostatic rebalancing agents, and most recently approved gene therapy. Several decades of preclinical and clinical trials have led to development of adeno-associated viral (AAV) vector-mediated gene transfer for endogenous production of factor VIII (FVIII) in hemophilia A (HA). Only one gene therapy product for HA (valoctocogene roxaparvovec) has been approved by regulatory authorities. Results of valoctocogene roxaparvovec trial show significant improvement in bleeding rates and use of factor replacement therapy; however, sustainability and duration of response show variability with overall decline in FVIII expression over time. Further challenges include untoward adverse effects involving liver toxicity requiring immunosuppression and development of neutralizing antibodies to AAV vector rendering future doses ineffective. Real-life applicability of gene therapy for HA will require appropriate patient screening, infrastructure setup, long-term monitoring including data collection of patient-reported outcomes and innovative payment schemes. This review article highlights the success and development of HA gene therapy trials, challenges including adverse outcomes and variability of response, and perspectives on approach to gene therapy including shared decision-making and need for future strategies to overcome the several unmet needs.
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Affiliation(s)
- Natasha S Bala
- Rady Children's Hospital San Diego, Hemophilia and Thrombosis Treatment Center, San Diego, California
- Department of Pediatrics, UC San Diego School of Medicine, La Jolla, California
| | - Courtney D Thornburg
- Rady Children's Hospital San Diego, Hemophilia and Thrombosis Treatment Center, San Diego, California
- Department of Pediatrics, UC San Diego School of Medicine, La Jolla, California
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Zhong M, Balakrishnan B, Guo A, Lai K. AAV9-based PMM2 gene replacement augments PMM2 expression and improves glycosylation in primary fibroblasts of patients with phosphomannomutase 2 deficiency (PMM2-CDG). Mol Genet Metab Rep 2024; 38:101035. [PMID: 38130891 PMCID: PMC10733668 DOI: 10.1016/j.ymgmr.2023.101035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023] Open
Abstract
Inherited deficiency of phosphomannomutase 2 (PMM2) (aka PMM2-CDG) is the most common congenital disorders of glycosylation (CDG) and has no cure. With debilitating morbidity and significant mortality, it is imperative to explore novel, safe, and effective therapies for the disease. Our Proof-of-Concept study showed that AAV9-PMM2 infection of patient fibroblasts augmented PMM2 expression and improved glycosylation. Thus, AAV9-PMM2 gene replacement is a promising therapeutic strategy for PMM2-CDG patients.
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Affiliation(s)
- M. Zhong
- Division of Medical Genetics, Department of Pediatrics, University of Utah Spencer Fox Eccles School of Medicine, USA
| | - B. Balakrishnan
- Division of Medical Genetics, Department of Pediatrics, University of Utah Spencer Fox Eccles School of Medicine, USA
| | - A.J. Guo
- Division of Medical Genetics, Department of Pediatrics, University of Utah Spencer Fox Eccles School of Medicine, USA
| | - K. Lai
- Division of Medical Genetics, Department of Pediatrics, University of Utah Spencer Fox Eccles School of Medicine, USA
- Department of Nutrition and Integrated Physiology, University of Utah College of Health, USA
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Wang J, Ye M, Zhu B. Peptide Self-Assembly Facilitating DNA Transfection and the Application in Inhibiting Cancer Cells. Molecules 2024; 29:932. [PMID: 38474444 DOI: 10.3390/molecules29050932] [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: 12/30/2023] [Revised: 02/03/2024] [Accepted: 02/11/2024] [Indexed: 03/14/2024] Open
Abstract
Non-viral vectors have been developing in gene delivery due to their safety and low immunogenicity. But their transfection effect is usually very low, thus limiting the application. Hence, we designed eight peptides (compounds 1-8). We compared their performances; compound 8 had the best transfection efficacy and biocompatibility. The transfection effect was similar with that of PEI, a most-widely-employed commercial transfection reagent. Atomic force microscope (AFM) images showed that the compound could self-assemble and the self-assembled peptide might encapsulate DNA. Based on these results, we further analyzed the inhibitory result in cancer cells and found that compound 8 could partially fight against Hela cells. Therefore, the compound is promising to pave the way for the development of more effective and less toxic transfection vectors.
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Affiliation(s)
- Jingyu Wang
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin 300070, China
| | - Min Ye
- College of Pharmacy, Southern Medical University, Guangzhou 510280, China
| | - Baokuan Zhu
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin 300070, China
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Chen Z, Herzog RW, Kaufman RJ. Cellular stress and coagulation factor production: when more is not necessarily better. J Thromb Haemost 2023; 21:3329-3341. [PMID: 37839613 PMCID: PMC10760459 DOI: 10.1016/j.jtha.2023.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/17/2023]
Abstract
Remarkably, it has been 40 years since the isolation of the 2 genes involved in hemophilia A (HA) and hemophilia B (HB), encoding clotting factor (F) VIII (FVIII) and FIX, respectively. Over the years, these advances led to the development of purified recombinant protein factors that are free of contaminating viruses from human pooled plasma for hemophilia treatments, reducing the morbidity and mortality previously associated with human plasma-derived clotting factors. These discoveries also paved the way for modified factors that have increased plasma half-lives. Importantly, more recent advances have led to the development and Food and Drug Administration approval of a hepatocyte-targeted, adeno-associated viral vector-mediated gene transfer approach for HA and HB. However, major concerns regarding the durability and safety of HA gene therapy remain to be resolved. Compared with FIX, FVIII is a much larger protein that is prone to misfolding and aggregation in the endoplasmic reticulum and is poorly secreted by the mammalian cells. Due to the constraint of the packaging capacity of adeno-associated viral vector, B-domain deleted FVIII rather than the full-length protein is used for HA gene therapy. Like full-length FVIII, B-domain deleted FVIII misfolds and is inefficiently secreted. Its expression in hepatocytes activates the cellular unfolded protein response, which is deleterious for hepatocyte function and survival and has the potential to drive hepatocellular carcinoma. This review is focused on our current understanding of factors limiting FVIII secretion and the potential pathophysiological consequences upon expression in hepatocytes.
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Affiliation(s)
- Zhouji Chen
- Degenerative Diseases Program, Center for Genetic Diseases and Aging Research, SBP Medical Discovery Institute, California, USA
| | - Roland W Herzog
- Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University, Indianapolis, Indiana, USA
| | - Randal J Kaufman
- Degenerative Diseases Program, Center for Genetic Diseases and Aging Research, SBP Medical Discovery Institute, California, USA.
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