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Leroy BP, Fischer MD, Flannery JG, MacLaren RE, Dalkara D, Scholl HPN, Chung DC, Spera C, Viriato D, Banhazi J. Gene Therapy for Inherited Retinal Disease: Long-Term Durability of Effect. Ophthalmic Res 2022; 66:179-196. [PMID: 36103843 DOI: 10.1159/000526317] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 07/27/2022] [Indexed: 12/23/2023]
Abstract
The recent approval of voretigene neparvovec (Luxturna®) for patients with biallelic RPE65 mutation-associated inherited retinal dystrophy with viable retinal cells represents an important step in the development of ocular gene therapies. Herein, we review studies investigating the episomal persistence of different recombinant adeno-associated virus (rAAV) vector genomes and the preclinical and clinical evidence of long-term effects of different RPE65 gene replacement therapies. A targeted review of articles published between 1974 and January 2021 in Medline®, Embase®, and other databases was conducted, followed by a descriptive longitudinal analysis of the clinical trial outcomes of voretigene neparvovec. Following an initial screening, 14 publications examining the episomal persistence of different rAAV genomes and 71 publications evaluating gene therapies in animal models were included. Viral genomes were found to persist for at least 22 months (longest study follow-up) as transcriptionally active episomes. Treatment effects lasting almost a decade were reported in canine disease models, with more pronounced effects the earlier the intervention. The clinical trial outcomes of voretigene neparvovec are consistent with preclinical findings and reveal sustained results for up to 7.5 years for the full-field light sensitivity threshold test and 5 years for the multi-luminance mobility test in the Phase I and Phase III trials, respectively. In conclusion, the therapeutic effect of voretigene neparvovec lasts for at least a decade in animal models and 7.5 years in human subjects. Since retinal cells can retain functionality over their lifetime after transduction, these effects may be expected to last even longer in patients with a sufficient number of outer retinal cells at the time of intervention.
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Affiliation(s)
- Bart P Leroy
- Department of Ophthalmology & Centre for Medical Genetics, Ghent University Hospital & Ghent University, Ghent, Belgium
- Division of Ophthalmology & Center for Cellular & Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - M Dominik Fischer
- University Eye Hospital, Centre for Ophthalmology, University Hospital Tübingen, Tübingen, Germany
- Oxford Eye Hospital, University of Oxford NHS Foundation Trust and NIHR Oxford Biomedical Research Centre, Oxford, UK
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - John G Flannery
- School of Optometry and the Helen Wills Neuroscience Institute, University of California-Berkeley, Berkeley, California, USA
| | - Robert E MacLaren
- Oxford Eye Hospital, University of Oxford NHS Foundation Trust and NIHR Oxford Biomedical Research Centre, Oxford, UK
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Deniz Dalkara
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
- Department of Ophthalmology, University Hospital Basel, University of Basel, Basel, Switzerland
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Gene therapy for mitochondrial diseases: Leber Hereditary Optic Neuropathy as the first candidate for a clinical trial. C R Biol 2014; 337:193-206. [PMID: 24702846 DOI: 10.1016/j.crvi.2013.11.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 11/28/2013] [Indexed: 12/30/2022]
Abstract
Mitochondrial disorders cannot be ignored anymore in most medical disciplines; indeed their minimum estimated prevalence is superior to 1 in 5000 births. Despite the progress made in the last 25 years on the identification of gene mutations causing mitochondrial pathologies, only slow progress was made towards their effective treatments. Ocular involvement is a frequent feature in mitochondrial diseases and corresponds to severe and irreversible visual handicap due to retinal neuron loss and optic atrophy. Interestingly, three clinical trials for Leber Congenital Amaurosis due to RPE65 mutations are ongoing since 2007. Overall, the feasibility and safety of ocular Adeno-Associated Virus delivery in adult and younger patients and consistent visual function improvements have been demonstrated. The success of gene-replacement therapy for RPE65 opens the way for the development of similar approaches for a broad range of eye disorders, including those with mitochondrial etiology such as Leber Hereditary Optic Neuropathy (LHON).
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Schmid F, Glaus E, Barthelmes D, Fliegauf M, Gaspar H, Nürnberg G, Nürnberg P, Omran H, Berger W, Neidhardt J. U1 snRNA-mediated gene therapeutic correction of splice defects caused by an exceptionally mild BBS mutation. Hum Mutat 2011; 32:815-24. [DOI: 10.1002/humu.21509] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Cwerman-Thibault H, Sahel JA, Corral-Debrinski M. Mitochondrial medicine: to a new era of gene therapy for mitochondrial DNA mutations. J Inherit Metab Dis 2011; 34:327-44. [PMID: 20571866 DOI: 10.1007/s10545-010-9131-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 05/12/2010] [Accepted: 05/17/2010] [Indexed: 01/01/2023]
Abstract
Mitochondrial disorders can no longer be ignored in most medical disciplines. Such disorders include specific and widespread organ involvement, with tissue degeneration or tumor formation. Primary or secondary actors, mitochondrial dysfunctions also play a role in the aging process. Despite progresses made in identification of their molecular bases, nearly everything remains to be done as regards therapy. Research dealing with mitochondrial physiology and pathology has >20 years of history around the world. We are involved, as are many other laboratories, in the challenge of finding ways to fight these diseases. However, our main limitation is the scarcety of animal models required for both understanding the molecular mechanisms underlying the diseases and evaluating therapeutic strategies. This is especially true for diseases due to mutations in mitochondrial DNA (mtDNA), since an authentic genetic model of mtDNA mutations is technically a very difficult task due to both the inability of manipulating the mitochondrial genome of living mammalian cells and to its multicopy nature. This has led researchers in the field to consider the prospect of gene therapy approaches that can roughly be divided into three groups: (1) import of wild-type copies or relevant sections of DNA or RNA into mitochondria, (2) manipulation of mitochondrial genetic content, and (3) rescue of a defect by expression of an engineered gene product from the nucleus (allotopic or xenotropic expression). We briefly introduce these concepts and indicate where promising progress has been made in the last decade.
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Koenekoop RK. Why some photoreceptors die, while others remain dormant: lessons from RPE65 and LRAT associated retinal dystrophies. Ophthalmic Genet 2011; 32:126-8. [PMID: 21268677 DOI: 10.3109/13816810.2010.544361] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE Why some photoreceptors die and other do not is not well understood, but is a fascinating and important emerging concept, now that gene and drug therapy have shown preliminary positive results in treatments for patients with gene specific retinal degenerations. RESULTS This review discusses these concepts and a new study that shows that continuous activation of the phototransduction cascade activates Bcl-2 apoptotic pathways. Knockout out of Bax revealed rescue from apoptosis, indicating that bax inhibition may be an avenue for pharmocological intervention.
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Leber's Hereditary Optic Neuropathy-Gene Therapy: From Benchtop to Bedside. J Ophthalmol 2010; 2011:179412. [PMID: 21253496 PMCID: PMC3021870 DOI: 10.1155/2011/179412] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 10/07/2010] [Accepted: 11/12/2010] [Indexed: 02/06/2023] Open
Abstract
Leber's hereditary optic neuropathy (LHON) is a maternally transmitted disorder caused by point mutations in mitochondrial DNA (mtDNA). Most cases are due to mutations in genes encoding subunits of the NADH-ubiquinone oxidoreductase that is Complex I of the electron transport chain (ETC). These mutations are located at nucleotide positions 3460, 11778, or 14484 in the mitochondrial genome. The disease is characterized by apoplectic, bilateral, and severe visual loss. While the mutated mtDNA impairs generation of ATP by all mitochondria, there is only a selective loss of retinal ganglion cells and degeneration of optic nerve axons. Thus, blindness is typically permanent. Half of the men and 10% of females who harbor the pathogenic mtDNA mutation actually develop the phenotype. This incomplete penetrance and gender bias is not fully understood. Additional mitochondrial and/or nuclear genetic factors may modulate the phenotypic expression of LHON. In a population-based study, the mtDNA background of haplogroup J was associated with an inverse relationship of low-ATP generation and increased production of reactive oxygen species (ROS). Effective therapy for LHON has been elusive. In this paper, we describe the findings of pertinent published studies and discuss the controversies of potential strategies to ameliorate the disease.
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