Lentiviral Gene Therapy for Artemis-Deficient SCID.

BACKGROUND: The DNA-repair enzyme Artemis is essential for rearrangement of T- and B-cell receptors. Mutations in DCLRE1C, which encodes Artemis, cause Artemis-deficient severe combined immunodeficiency (ART-SCID), which is poorly responsive to allogeneic hematopoietic-cell transplantation. METHODS: We carried out a phase 1-2 clinical study of the transfusion of autologous CD34+ cells, transfected with a lentiviral vector containing DCLRE1C, in 10 infants with newly diagnosed ART-SCID. We followed them for a median of 31.2 months. RESULTS: Marrow harvest, busulfan conditioning, and lentiviral-transduced CD34+ cell infusion produced the expected grade 3 or 4 adverse events. All the procedures met prespecified criteria for feasibility at 42 days after infusion. Gene-marked T cells were detected at 6 to 16 weeks after infusion in all the patients. Five of 6 patients who were followed for at least 24 months had T-cell immune reconstitution at a median of 12 months. The diversity of T-cell receptor ß chains normalized by 6 to 12 months. Four patients who were followed for at least 24 months had sufficient B-cell numbers, IgM concentration, or IgM isohemagglutinin titers to permit discontinuation of IgG infusions. Three of these 4 patients had normal immunization responses, and the fourth has started immunizations. Vector insertion sites showed no evidence of clonal expansion. One patient who presented with cytomegalovirus infection received a second infusion of gene-corrected cells to achieve T-cell immunity sufficient for viral clearance. Autoimmune hemolytic anemia developed in 4 patients 4 to 11 months after infusion; this condition resolved after reconstitution of T-cell immunity. All 10 patients were healthy at the time of this report. CONCLUSIONS: Infusion of lentiviral gene-corrected autologous CD34+ cells, preceded by pharmacologically targeted low-exposure busulfan, in infants with newly diagnosed ART-SCID resulted in genetically corrected and functional T and B cells. (Funded by the California Institute for Regenerative Medicine and the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT03538899.).

Assessment of Visual Function with Cotoretigene Toliparvovec in X-Linked Retinitis Pigmentosa in the Randomized XIRIUS Phase 2/3 Study.

PURPOSE: Cotoretigene toliparvovec (BIIB112/AAV8-RPGR) is an investigational vector-based gene therapy designed to provide a full-length, codon-optimized retinitis pigmentosa GTPase regulator (RPGR) protein to individuals with RPGR-associated X-linked retinitis pigmentosa (XLRP). We assessed efficacy and tolerability of cotoretigene toliparvovec subretinal gene therapy. DESIGN: Part 2 of the XIRIUS trial (ClinicalTrials.gov identifier, NCT03116113) was a phase 2/3, 12-month, randomized (1:1:1) dose-expansion study. PARTICIPANTS: Male patients ≥10 years of age with RPGR-associated XLRP were included. METHODS: Participants were randomized 1:1:1 to receive low-dose subretinal cotoretigene toliparvovec (5 × 1010 vector genomes/eye), high-dose cotoretigene toliparvovec (2.5 × 1011 vector genomes/eye) or to be an untreated control participant. MAIN OUTCOME MEASURES: The primary end point was the percentage of participants meeting microperimetry responder criteria (≥ 7-dB improvement at ≥ 5 of 16 central loci). Secondary end points included change from baseline in retinal sensitivity at the central 16 loci and the entire 68 loci at 12 months and change from baseline in low-luminance visual acuity (LLVA) at 12 months, as well as the proportion of eyes with a ≥ 15-Early Treatment Diabetic Retinopathy Study ETDRS letter LLVA and ≥ 10-ETDRS letter LLVA change from baseline at month 12. RESULTS: Because of the impact of the COVID-19 pandemic, enrollment ended before reaching the initial target, leaving the trial underpowered. Twenty-nine participants were included (low-dose group, n = 10; high-dose group, n = 10; control group, n = 9). At month 12, the percentage of participants meeting microperimetry responder criteria was not significantly different between either cotoretigene toliparvovec group (low dose, 37.5% [P = 0.3181]; high dose, 25.0% [P = 0.5177]) and the control group (22.2%). However, the mean change from baseline in microperimetry sensitivity improved significantly with the low-dose group versus the control group at month 12 (P = 0.0350). Significant improvement in LLVA occurred in the low-dose group versus the control group at month 12 (33.3% difference [80% confidence interval, 14.7%-55.2%]; P = 0.0498). Three ocular-related serious adverse events (SAEs) occurred in the low-dose group versus 7 SAEs in the high-dose group. CONCLUSIONS: The primary microperimetry end point was not met. Significant improvements in LLVA and mean microperimetry were observed compared with controls and fewer SAEs occured with low-dose compared with high dose cotoretigene toliparvovec. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Lethal immunotoxicity in high-dose systemic AAV therapy.

High-dose systemic gene therapy with adeno-associated virus (AAV) is in clinical trials to treat various inherited diseases. Despite remarkable success in spinal muscular atrophy and promising results in other diseases, fatality has been observed due to liver, kidney, heart, or lung failure. Innate and adaptive immune responses to the vector play a critical role in the toxicity. Host factors also contribute to patient death. This mini-review summarizes clinical findings and calls for concerted efforts from all stakeholders to better understand the mechanisms underlying lethality in AAV gene therapy and to develop effective strategies to prevent/treat high-dose systemic AAV-gene-therapy-induced immunotoxicity.

Insights in ChAdOx1 nCoV-19 vaccine-induced immune thrombotic thrombocytopenia.

SARS-CoV-2 vaccine ChAdOx1 nCoV-19 (AstraZeneca) causes a thromboembolic complication termed vaccine-induced immune thrombotic thrombocytopenia (VITT). Using biophysical techniques, mouse models, and analysis of VITT patient samples, we identified determinants of this vaccine-induced adverse reaction. Super-resolution microscopy visualized vaccine components forming antigenic complexes with platelet factor 4 (PF4) on platelet surfaces to which anti-PF4 antibodies obtained from VITT patients bound. PF4/vaccine complex formation was charge-driven and increased by addition of DNA. Proteomics identified substantial amounts of virus production-derived T-REx HEK293 proteins in the ethylenediaminetetraacetic acid (EDTA)-containing vaccine. Injected vaccine increased vascular leakage in mice, leading to systemic dissemination of vaccine components known to stimulate immune responses. Together, PF4/vaccine complex formation and the vaccine-stimulated proinflammatory milieu trigger a pronounced B-cell response that results in the formation of high-avidity anti-PF4 antibodies in VITT patients. The resulting high-titer anti-PF4 antibodies potently activated platelets in the presence of PF4 or DNA and polyphosphate polyanions. Anti-PF4 VITT patient antibodies also stimulated neutrophils to release neutrophil extracellular traps (NETs) in a platelet PF4-dependent manner. Biomarkers of procoagulant NETs were elevated in VITT patient serum, and NETs were visualized in abundance by immunohistochemistry in cerebral vein thrombi obtained from VITT patients. Together, vaccine-induced PF4/adenovirus aggregates and proinflammatory reactions stimulate pathologic anti-PF4 antibody production that drives thrombosis in VITT. The data support a 2-step mechanism underlying VITT that resembles the pathogenesis of (autoimmune) heparin-induced thrombocytopenia.

Predicting genotoxicity of viral vectors for stem cell gene therapy using gene expression-based machine learning.

Hematopoietic stem cell gene therapy is emerging as a promising therapeutic strategy for many diseases of the blood and immune system. However, several individuals who underwent gene therapy in different trials developed hematological malignancies caused by insertional mutagenesis. Preclinical assessment of vector safety remains challenging because there are few reliable assays to screen for potential insertional mutagenesis effects in vitro. Here we demonstrate that genotoxic vectors induce a unique gene expression signature linked to stemness and oncogenesis in transduced murine hematopoietic stem and progenitor cells. Based on this finding, we developed the surrogate assay for genotoxicity assessment (SAGA). SAGA classifies integrating retroviral vectors using machine learning to detect this gene expression signature during the course of in vitro immortalization. On a set of benchmark vectors with known genotoxic potential, SAGA achieved an accuracy of 90.9%. SAGA is more robust and sensitive and faster than previous assays and reliably predicts a mutagenic risk for vectors that led to leukemic severe adverse events in clinical trials. Our work provides a fast and robust tool for preclinical risk assessment of gene therapy vectors, potentially paving the way for safer gene therapy trials.

Early Phase Clinical Immunogenicity of Valoctocogene Roxaparvovec, an AAV5-Mediated Gene Therapy for Hemophilia A.

Evaluation of immune responses to adeno-associated virus (AAV)-mediated gene therapies prior to and following dose administration plays a key role in determining therapeutic safety and efficacy. This report describes up to 3 years of immunogenicity data following administration of valoctocogene roxaparvovec (BMN 270), an AAV5-mediated gene therapy encoding human B domain-deleted FVIII (hFVIII-SQ) in a phase 1/2 clinical study of adult males with severe hemophilia A. Patients with pre-existing humoral immunity to AAV5 or with a history of FVIII inhibitors were excluded from the trial. Blood plasma and peripheral blood mononuclear cell (PBMC) samples were collected at regular intervals following dose administration for assessment of humoral and cellular immune responses to both the AAV5 vector and transgene-expressed hFVIII-SQ. The predominant immune response elicited by BMN 270 administration was largely limited to the development of antibodies against the AAV5 capsid that were cross-reactive with other common AAV serotypes. No FVIII inhibitor responses were observed within 3 years following dose administration. In a context of prophylactic or on-demand corticosteroid immunosuppression given after vector infusion, AAV5 and hFVIII-SQ peptide-specific cellular immune responses were intermittently detected by an interferon (IFN)-γ and tumor necrosis factor (TNF)-α FluoroSpot assay, but they were not clearly associated with detrimental safety events or changes in efficacy measures.

Advances and challenges for hemophilia gene therapy.

Hemophilia is an X-linked inherited bleeding disorder, resulting from defects in the F8 (hemophilia A) or F9 (hemophilia B) genes. Persons with hemophilia have bleeding episodes into the soft tissues and joints, which are treated with self-infusion of factor VIII or IX concentrates. Hemophilia provides an attractive target for gene therapy studies, due to the monogenic nature of these disorders and easily measurable endpoints (factor levels and bleed rates). All successful, pre-clinical and clinical studies to date have utilized recombinant adeno-associated viral (AAV) vectors for factor VIII or IX hepatocyte transduction. Recent clinical data have presented normalization of factor levels in some patients with improvements in bleed rate and quality of life. The main toxicity seen within these studies has been early transient elevation in liver enzymes, with variable effect on transgene expression. Although long-term data are awaited, durable expression has been seen within the hemophilia dog model with no late-toxicity or oncogenesis. There are a number of phase III studies currently recruiting; however, there may be some limitations in translating these data to clinical practice, due to inclusion/exclusion criteria. AAV-based gene therapy is one of a number of novel approaches for treatment of hemophilia with other gene therapy (in vivo and ex vivo) and non-replacement therapies progressing through clinical trials. Availability of these high-cost novel therapeutics will require evolution of both clinical and financial healthcare services to allow equitable personalization of care for persons with hemophilia.

Non-Viral Vector-Mediated Gene Therapy for ALS: Challenges and Future Perspectives.

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease, for which no effective treatment is yet available to either slow or terminate it. Recent advances in gene therapy renew hope for developing an effective approach to control this disease. Non-viral vectors, such as lipid- and polymer-based nanoparticles, cationic polymers, and exosomes, can effectively transfer genes into primary neurons. The resulting gene expression can be long-term, stable, and without immunological complications, which is essential for the effective management of neurological disorders. This Review will first describe the current research and clinical stage of novel therapies for ALS. It will then touch on the journey of non-viral vector use in ALS, subsequently highlighting the application of non-viral vector-mediated gene therapy. The bottlenecks in the translation of non-viral vectors for ALS treatment are also discussed, including the biological barriers of systemic administration and the issues of "when, where, and how much?" for effective gene delivery. The prospect of employing emerging techniques, such as CRISPR-Cas9 gene editing, stem cell methodology, and low-intensity focused ultrasound for fueling the transport of non-viral vectors to the central nervous system for personalized gene therapy, is briefly discussed in the context of ALS. Despite the challenging road that lies ahead, with the current expansion in interest and technological advancement in non-viral vector-delivered gene therapy for ALS, we hold hope that the field is headed toward a positive future.

Immune Responses to Viral Gene Therapy Vectors.

Several viral vector-based gene therapy drugs have now received marketing approval. A much larger number of additional viral vectors are in various stages of clinical trials for the treatment of genetic and acquired diseases, with many more in pre-clinical testing. Efficiency of gene transfer and ability to provide long-term therapy make these vector systems very attractive. In fact, viral vector gene therapy has been able to treat or even cure diseases for which there had been no or only suboptimal treatments. However, innate and adaptive immune responses to these vectors and their transgene products constitute substantial hurdles to clinical development and wider use in patients. This review provides an overview of the type of immune responses that have been documented in animal models and in humans who received gene transfer with one of three widely tested vector systems, namely adenoviral, lentiviral, or adeno-associated viral vectors. Particular emphasis is given to mechanisms leading to immune responses, efforts to reduce vector immunogenicity, and potential solutions to the problems. At the same time, we point out gaps in our knowledge that should to be filled and problems that need to be addressed going forward.

AAV Vector Immunogenicity in Humans: A Long Journey to Successful Gene Transfer.

Gene therapy with adeno-associated virus (AAV) vectors has demonstrated safety and long-term efficacy in a number of trials across target organs, including eye, liver, skeletal muscle, and the central nervous system. Since the initial evidence that AAV vectors can elicit capsid T cell responses in humans, which can affect the duration of transgene expression, much progress has been made in understanding and modulating AAV vector immunogenicity. It is now well established that exposure to wild-type AAV results in priming of the immune system against the virus, with development of both humoral and T cell immunity. Aside from the neutralizing effect of antibodies, the impact of pre-existing immunity to AAV on gene transfer is still poorly understood. Herein, we review data emerging from clinical trials across a broad range of gene therapy applications. Common features of immune responses to AAV can be found, suggesting, for example, that vector immunogenicity is dose-dependent, and that innate immunity plays an important role in the outcome of gene transfer. A range of host-specific factors are also likely to be important, and a comprehensive understanding of the mechanisms driving AAV vector immunogenicity in humans will be key to unlocking the full potential of in vivo gene therapy.

Muscle-Directed Delivery of an AAV1 Vector Leads to Capsid-Specific T Cell Exhaustion in Nonhuman Primates and Humans.

With the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) approvals for Zolgensma, Luxturna, and Glybera, recombinant adeno-associated viruses (rAAVs) are considered efficient tools for gene transfer. However, studies in animals and humans demonstrate that intramuscular (IM) AAV delivery can trigger immune responses to AAV capsids and/or transgenes. IM delivery of rAAV1 in humans has also been described to induce tolerance to rAAV characterized by the presence of capsid-specific regulatory T cells (Tregs) in periphery. To understand mechanisms responsible for tolerance and parameters involved, we tested 3 muscle-directed administration routes in rhesus monkeys: IM delivery, venous limb perfusion, and the intra-arterial push and dwell method. These 3 methods were well tolerated and led to transgene expression. Interestingly, gene transfer in muscle led to Tregs and exhausted T cell infiltrates in situ at both day 21 and day 60 post-injection. In human samples, an in-depth analysis of the functionality of these cells demonstrates that capsid-specific exhausted T cells are detected after at least 5 years post-vector delivery and that the exhaustion can be reversed by blocking the checkpoint pathway. Overall, our study shows that persisting transgene expression after gene transfer in muscle is mediated by Tregs and exhausted T cells.

The Effect of CpG Sequences on Capsid-Specific CD8+ T Cell Responses to AAV Vector Gene Transfer.

Transfer of genes by adeno-associated virus (AAV) vectors is benefiting patients with particular genetic defects. Challenges remain by rejection of AAV-transduced cells, which may be caused by CD8+ T lymphocytes directed to AAV capsid antigens. Reducing the number of CpG motifs from the genome of AAV vectors reduces expansion of naive T cells directed against an epitope within the capsid. In contrast, AAV capsid-specific memory CD8+ T cells respond more vigorously to AAV vectors lacking CpG motifs than to those with CpG motifs presumably reflecting dampening of T cell expansion by cytokines from the innate immune system. Depending on the purification method, AAV vector preparations can contain substantial amounts of empty AAV particles that failed to package the genome. Others have used empty particles as decoys to AAV-neutralizing antibodies. We tested if empty AAV vectors given alone or mixed with genome-containing AAV vectors induce proliferation of naive or memory CD8+ T cells directed to an antigen within an AAV capsid. Naive CD8+ T cells failed to respond to empty AAV vectors, which in contrast induced expansion of AAV-specific memory CD8+ T cells.

Adenovirus-Antibody Complexes Contributed to Lethal Systemic Inflammation in a Gene Therapy Trial.

Intra-arterial administration of an adenovirus serotype 5 (Ad5) vector in a gene therapy trial caused lethal, systemic inflammation in subject 019 with ornithine transcarbamylase deficiency. This unanticipated inflammatory response was absent in another subject receiving the same vector dose and in 16 subjects receiving lower vector doses. We hypothesized that an immune memory to a previous natural adenovirus infection enhanced the immune response to high-dose systemic Ad5 vector, causing the exaggerated immune response in subject 019. To investigate this, we found that rabbit polyclonal sera to Ad5 and pooled human immunoglobulin (Ig) inhibited Ad5 vector transduction of non-immune cells in vitro, but enhanced transduction and activation of human dendritic cells (DCs). Sera from approximately 7% of normal human subjects and 50% of patients treated topically with Ad5 vectors enhanced Ad5 transduction and activation of DCs, apparently from formation of Ig-Ad5 immune complexes and binding to DCs through FcγR. Subject 019's blood substantially increased Ad5-vector activation of human DC primary cultures at levels exceeding those from normal subjects. Although this study is based on one event in a single subject, the results implicate a pre-existing humoral immune response to Ad5 in the lethal systemic inflammatory response that occurred in subject 019.

Long-Term Follow-Up of the First in Human Intravascular Delivery of AAV for Gene Transfer: AAV2-hFIX16 for Severe Hemophilia B.

Adeno-associated virus (AAV) vectors are a leading platform for gene-based therapies for both monogenic and complex acquired disorders. The success of AAV gene transfer highlights the need to answer outstanding clinical questions of safety, durability, and the nature of the human immune response to AAV vectors. Here, we present longitudinal follow-up data of subjects who participated in the first trial of a systemically delivered AAV vector. Adult males (n = 7) with severe hemophilia B received an AAV2 vector at doses ranging from 8 × 1010 to 2 × 1012 vg/kg to target hepatocyte-specific expression of coagulation factor IX; a subset (n = 4) was followed for 12-15 years post-vector administration. No major safety concerns were observed. There was no evidence of sustained hepatic toxicity or development of hepatocellular carcinoma as assessed by liver transaminase values, serum α-fetoprotein, and liver ultrasound. Subjects demonstrated persistent, increased AAV neutralizing antibodies (NAbs) to the infused AAV serotype 2 (AAV2) as well as all other AAV serotypes tested (AAV5 and AAV8) for the duration of follow-up. These data represent the longest available longitudinal follow-up data of subjects who received intravascular AAV and support the preliminary safety of intravascular AAV administration at the doses tested in adults. Data demonstrate, for the first time, the persistence of high-titer, multi-serotype cross-reactive AAV NAbs for up to 15 years post- AAV vector administration. Our observations are broadly applicable to the development of AAV-mediated gene therapy.

Type I IFN Sensing by cDCs and CD4+ T Cell Help Are Both Requisite for Cross-Priming of AAV Capsid-Specific CD8+ T Cells.

Adeno-associated virus (AAV) vectors are widely used in clinical gene therapy to correct genetic disease by in vivo gene transfer. Although the vectors are useful, in part because of their limited immunogenicity, immune responses directed at vector components have complicated applications in humans. These include, for instance, innate immune sensing of vector components by plasmacytoid dendritic cells (pDCs), which sense the vector DNA genome via Toll-like receptor 9. Adaptive immune responses employ antigen presentation by conventional dendritic cells (cDCs), which leads to cross-priming of capsid-specific CD8+ T cells. In this study, we sought to determine the mechanisms that promote licensing of cDCs, which is requisite for CD8+ T cell activation. Blockage of type 1 interferon (T1 IFN) signaling by monoclonal antibody therapy prevented cross-priming. Furthermore, experiments in cell-type-restricted knockout mice showed a specific requirement for the receptor for T1 IFN (IFNaR) in cDCs. In contrast, natural killer (NK) cells are not needed, indicating a direct rather than indirect effect of T1 IFN on cDCs. In addition, co-stimulation by CD4+ T cells via CD40-CD40L was required for cross-priming, and blockage of co-stimulation but not of T1 IFN additionally reduced antibody formation against capsid. These mechanistic insights inform the development of targeted immune interventions.

Coagulopathies after Vaccination against SARS-CoV-2 May Be Derived from a Combined Effect of SARS-CoV-2 Spike Protein and Adenovirus Vector-Triggered Signaling Pathways.

Novel coronavirus SARS-CoV-2 has resulted in a global pandemic with worldwide 6-digit infection rates and thousands of death tolls daily. Enormous efforts are undertaken to achieve high coverage of immunization to reach herd immunity in order to stop the spread of SARS-CoV-2 infection. Several SARS-CoV-2 vaccines based on mRNA, viral vectors, or inactivated SARS-CoV-2 virus have been approved and are being applied worldwide. However, the recent increased numbers of normally very rare types of thromboses associated with thrombocytopenia have been reported, particularly in the context of the adenoviral vector vaccine ChAdOx1 nCoV-19 from Astra Zeneca. The statistical prevalence of these side effects seems to correlate with this particular vaccine type, i.e., adenoviral vector-based vaccines, but the exact molecular mechanisms are still not clear. The present review summarizes current data and hypotheses for molecular and cellular mechanisms into one integrated hypothesis indicating that coagulopathies, including thromboses, thrombocytopenia, and other related side effects, are correlated to an interplay of the two components in the vaccine, i.e., the spike antigen and the adenoviral vector, with the innate and immune systems, which under certain circumstances can imitate the picture of a limited COVID-19 pathological picture.

Gene Therapy for Mucopolysaccharidosis Type II-A Review of the Current Possibilities.

Mucopolysaccharidosis type II (MPS II) is a lysosomal storage disorder based on a mutation in the IDS gene that encodes iduronate 2-sulphatase. As a result, there is an accumulation of glycosaminoglycans-heparan sulphate and dermatan sulphate-in almost all body tissues, which leads to their dysfunction. Currently, the primary treatment is enzyme replacement therapy, which improves the course of the disease by reducing somatic symptoms, including hepatomegaly and splenomegaly. The enzyme, however, does not cross the blood-brain barrier, and no improvement in the function of the central nervous system has been observed in patients with the severe form of the disease. An alternative method of treatment that solves typical problems of enzyme replacement therapy is gene therapy, i.e., delivery of the correct gene to target cells through an appropriate vector. Much progress has been made in applying gene therapy for MPS II, from cellular models to human clinical trials. In this article, we briefly present the history and basics of gene therapy and discuss the current state of knowledge about the methods of this therapy in mucopolysaccharidosis type II.

Advances in the gene therapy of monogenic blood cell diseases.

Hematopoietic gene therapy has markedly progressed during the last 15 years both in terms of safety and efficacy. While a number of serious adverse events (SAE) were initially generated as a consequence of genotoxic insertions of gamma-retroviral vectors in the cell genome, no SAEs and excellent outcomes have been reported in patients infused with autologous hematopoietic stem cells (HSCs) transduced with self-inactivated lentiviral and gammaretroviral vectors. Advances in the field of HSC gene therapy have extended the number of monogenic diseases that can be treated with these approaches. Nowadays, evidence of clinical efficacy has been shown not only in primary immunodeficiencies, but also in other hematopoietic diseases, including beta-thalassemia and sickle cell anemia. In addition to the rapid progression of non-targeted gene therapies in the clinic, new approaches based on gene editing have been developed thanks to the discovery of designed nucleases and improved non-integrative vectors, which have markedly increased the efficacy and specificity of gene targeting to levels compatible with its clinical application. Based on advances achieved in the field of gene therapy, it can be envisaged that these therapies will soon be part of the therapeutic approaches used to treat life-threatening diseases of the hematopoietic system.

Study protocol of a Phase I/IIa clinical trial of Ad-SGE-REIC for treatment of recurrent malignant glioma.

Malignant glioma is one of the most common brain cancers in humans, which is very devastating. The expression of reduced expression in immortalized cells/Dickkopf-3 (REIC/Dkk-3) is decreased in various human cancers. Lately, we have developed a novel second-generation adenoviral vector that expresses REIC/Dkk-3 (Ad-SGE-REIC) and revealed its antiglioma efficacy. The present investigator-initiated clinical trial is a single-arm, prospective, nonrandomized, noncomparative, open-label, single-center trial performed at Okayama University Hospital, Okayama, Japan. The primary end points are dose-limiting toxicities and the incidence of adverse events. The secondary end points are the objective response rate and immunological assessment. Use of Ad-SGE-REIC will help to improve the prognosis of patients with malignant brain tumors.

Gene Therapy Corrects Brain and Behavioral Pathologies in CLN6-Batten Disease.

CLN6-Batten disease, a form of neuronal ceroid lipofuscinosis is a rare lysosomal storage disorder presenting with gradual declines in motor, visual, and cognitive abilities and early death by 12-15 years of age. We developed a self-complementary adeno-associated virus serotype 9 (scAAV9) vector expressing the human CLN6 gene under the control of a chicken ß-actin (CB) hybrid promoter. Intrathecal delivery of scAAV9.CB.hCLN6 into the cerebrospinal fluid (CSF) of the lumbar spinal cord of 4-year-old non-human primates was safe, well tolerated, and led to efficient targeting throughout the brain and spinal cord. A single intracerebroventricular (i.c.v.) injection at post-natal day 1 in Cln6 mutant mice delivered scAAV9.CB.CLN6 directly into the CSF, and it prevented or drastically reduced all of the pathological hallmarks of Batten disease. Moreover, there were significant improvements in motor performance, learning and memory deficits, and survival in treated Cln6 mutant mice, extending survival from 15 months of age (untreated) to beyond 21 months of age (treated). Additionally, many parameters were similar to wild-type counterparts throughout the lifespan of the treated mice.