Gene therapy is an innovative treatment for Primary Immune Deficiencies (PIDs) that uses autologous hematopoietic stem cell transplantation to deliver stem cells with added or edited versions of the ...missing or malfunctioning gene that causes the PID. Initial studies of gene therapy for PIDs in the 1990-2000's used integrating murine gamma-retroviral vectors. While these studies showed clinical efficacy in many cases, especially with the administration of marrow cytoreductive conditioning before cell re-infusion, these vectors caused genotoxicity and development of leukoproliferative disorders in several patients. More recent studies used lentiviral vectors in which the enhancer elements of the long terminal repeats self-inactivate during reverse transcription ("SIN" vectors). These SIN vectors have excellent safety profiles and have not been reported to cause any clinically significant genotoxicity. Gene therapy has successfully treated several PIDs including Adenosine Deaminase Severe Combined Immunodeficiency (SCID), X-linked SCID, Artemis SCID, Wiskott-Aldrich Syndrome, X-linked Chronic Granulomatous Disease and Leukocyte Adhesion Deficiency-I. In all, gene therapy for PIDs has progressed over the recent decades to be equal or better than allogeneic HSCT in terms of efficacy and safety. Further improvements in methods should lead to more consistent and reliable efficacy from gene therapy for a growing list of PIDs.
Summary
Severe combined immune deficiency due to adenosine deaminase deficiency (ADA SCID) is an inborn error of immunity with pan‐lymphopenia, due to accumulated cytotoxic adenine metabolites. ADA ...SCID has been treated using gene therapy with a normal human ADA gene added to autologous hematopoietic stem cells (HSC) for over 30 years. Iterative improvements in vector design, HSC processing methods, and clinical HSC transplant procedures have led nearly all ADA SCID gene therapy patients to achieve consistently beneficial immune restoration with stable engraftment of ADA gene‐corrected HSC over the duration of observation (as long as 20 years). One gene therapy for ADA SCID is approved by the European Medicines Agency (EMA) in the European Union (EU) and another is being advanced to licensure in the U.S. and U.K. Despite the clear‐cut benefits and safety of this curative gene and cell therapy, it remains challenging to achieve sustained availability and access, especially for rare disorders like ADA SCID.
Gene therapy comes of age Dunbar, Cynthia E; High, Katherine A; Joung, J Keith ...
Science (American Association for the Advancement of Science),
01/2018, Letnik:
359, Številka:
6372
Journal Article
Recenzirano
After almost 30 years of promise tempered by setbacks, gene therapies are rapidly becoming a critical component of the therapeutic armamentarium for a variety of inherited and acquired human ...diseases. Gene therapies for inherited immune disorders, hemophilia, eye and neurodegenerative disorders, and lymphoid cancers recently progressed to approved drug status in the United States and Europe, or are anticipated to receive approval in the near future. In this Review, we discuss milestones in the development of gene therapies, focusing on direct in vivo administration of viral vectors and adoptive transfer of genetically engineered T cells or hematopoietic stem cells. We also discuss emerging genome editing technologies that should further advance the scope and efficacy of gene therapy approaches.
Gene therapy for blood diseases Kohn, Donald B
Current opinion in biotechnology,
December 2019, 2019-12-00, 20191201, Letnik:
60
Journal Article
Recenzirano
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•Genetic blood diseases may either involve blood plasma proteins or blood cells.•Gene addition or gene editing may be used to ameliorate these diseases.•Protein deficiencies are ...mostly treated in vivo by gene addition or editing.•Blood cell defects are mostly treated ex vivo by gene addition or editing.•Clinical trials of gene therapy for these diseases show clinical benefits.
Genetic diseases affecting proteins and cells composing the blood may be treated by gene therapy using gene addition or gene editing methods. Protein deficiencies (e.g. hemophilia) are being approached using in vivo gene delivery by adeno-associated virus (AAV) vectors for therapeutic gene addition or gene editing. Blood cell diseases (e.g. sickle cell disease) are being approached using ex vivo gene addition or gene editing to treat isolated blood-forming hematopoietic stem cells or T cells that are then re-transplanted. In recent years, there has been much progress, and gene therapy is now routinely providing clinical benefit to patients with a variety of conditions. Several of these gene therapies have been licensed in the U.S. and EU and more for other disorders are being advanced toward licensure. The scope of therapeutic activity for gene therapy is expected to continue to expand as the technical capabilities advance.
The use of allogeneic hematopoietic stem cells (HSCs) to treat genetic blood cell diseases has become a clinical standard but is limited by the availability of suitable matched donors and potential ...immunologic complications. Gene therapy using autologous HSCs should avoid these limitations and thus may be safer. Progressive improvements in techniques for genetic correction of HSCs, by either vector gene addition or gene editing, are facilitating successful treatments for an increasing number of diseases. We highlight the progress, successes, and remaining challenges toward the development of HSC gene therapies and discuss lessons they provide for the development of future clinical stem cell therapies.
Morgan et al. discuss the progress, successes, and remaining challenges toward the development of hematopoietic stem cell gene therapies and highlight lessons learned and how they can inform the development of future clinical stem cell therapies.
Background The approach to the diagnosis of severe combined immunodeficiency disease (SCID) and related disorders varies among institutions and countries. Objectives The Primary Immune Deficiency ...Treatment Consortium attempted to develop a uniform set of criteria for diagnosing SCID and related disorders and has evaluated the results as part of a retrospective study of SCID in North America. Methods Clinical records from 2000 through 2009 at 27 centers in North America were collected on 332 children treated with hematopoietic stem cell transplantation (HCT), enzyme replacement therapy, or gene therapy for SCID and related disorders. Eligibility for inclusion in the study and classification into disease groups were established by using set criteria and applied by an expert review group. Results Two hundred eighty-five (86%) of the patients were determined to be eligible, and 47 (14%) were not eligible. Of the 285 eligible patients, 84% were classified as having typical SCID; 13% were classified as having leaky SCID, Omenn syndrome, or reticular dysgenesis; and 3% had a history of enzyme replacement or gene therapy. Detection of a genotype predicting an SCID phenotype was accepted for eligibility. Reasons for noneligibility were failure to demonstrate either impaired lymphocyte proliferation or maternal T-cell engraftment. Overall (n = 332) rates of testing were as follows: proliferation to PHA, 77%; maternal engraftment, 35%; and genotype, 79% (mutation identified in 62%). Conclusion Lack of complete laboratory evaluation of patients before HCT presents a significant barrier to definitive diagnosis of SCID and related disorders and prevented inclusion of subjects in our observational HCT study. This lesson is critical for patient care, as well as the design of future prospective treatment studies for such children because a well-defined and consistent study population is important for precision in outcomes analysis.
Mutations in DMD disrupt the reading frame, prevent dystrophin translation, and cause Duchenne muscular dystrophy (DMD). Here we describe a CRISPR/Cas9 platform applicable to 60% of DMD patient ...mutations. We applied the platform to DMD-derived hiPSCs where successful deletion and non-homologous end joining of up to 725 kb reframed the DMD gene. This is the largest CRISPR/Cas9-mediated deletion shown to date in DMD. Use of hiPSCs allowed evaluation of dystrophin in disease-relevant cell types. Cardiomyocytes and skeletal muscle myotubes derived from reframed hiPSC clonal lines had restored dystrophin protein. The internally deleted dystrophin was functional as demonstrated by improved membrane integrity and restoration of the dystrophin glycoprotein complex in vitro and in vivo. Furthermore, miR31 was reduced upon reframing, similar to observations in Becker muscular dystrophy. This work demonstrates the feasibility of using a single CRISPR pair to correct the reading frame for the majority of DMD patients.
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•Largest CRISPR/Cas9-mediated deletion of 725 kb of DMD•Reframed DMD hiPSCs differentiated to cardiac and skeletal muscle express dystrophin•Internally deleted dystrophin demonstrates functionality in vitro and in vivo•This single gRNA pair is therapeutically relevant to 60% of DMD mutations
Young et al. demonstrate restoration of the DMD reading frame by CRISPR/Cas9-mediated deletion of up to 725 kb in hiPSCs as a therapeutic strategy for 60% of Duchenne muscular dystrophy patients. The resulting internally deleted protein is shown to be functional in vitro and in vivo.
Gene therapy using hematopoietic stem cells (HSC) has developed over the past 3 decades, with progressive improvements in the efficacy and safety. Autologous transplantation of HSC modified with ...murine gammaretroviral vectors first showed clinical benefits for patients with several primary immune deficiencies, but some of these patients suffered complications from vector-related genotoxicity. Lentiviral vectors have been used recently for gene addition to HSC and have yielded clinical benefits for primary immune deficiencies, metabolic diseases, and hemoglobinopathies, without vector-related complications. Gene editing using site-specific endonucleases is emerging as a promising technology for gene therapy and is moving into clinical trials.
Genetic diseases of blood cells are prime candidates for treatment through ex vivo gene editing of CD34
hematopoietic stem/progenitor cells (HSPCs), and a variety of technologies have been proposed ...to treat these disorders. Sickle cell disease (SCD) is a recessive genetic disorder caused by a single-nucleotide polymorphism in the β-globin gene (HBB). Sickle hemoglobin damages erythrocytes, causing vasoocclusion, severe pain, progressive organ damage, and premature death. We optimize design and delivery parameters of a ribonucleoprotein (RNP) complex comprising Cas9 protein and unmodified single guide RNA, together with a single-stranded DNA oligonucleotide donor (ssODN), to enable efficient replacement of the SCD mutation in human HSPCs. Corrected HSPCs from SCD patients produced less sickle hemoglobin RNA and protein and correspondingly increased wild-type hemoglobin when differentiated into erythroblasts. When engrafted into immunocompromised mice, ex vivo treated human HSPCs maintain SCD gene edits throughout 16 weeks at a level likely to have clinical benefit. These results demonstrate that an accessible approach combining Cas9 RNP with an ssODN can mediate efficient HSPC genome editing, enables investigator-led exploration of gene editing reagents in primary hematopoietic stem cells, and suggests a path toward the development of new gene editing treatments for SCD and other hematopoietic diseases.
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