Biomaterial Database

Twenty-Five Years of Gene Therapy for ADA-SCID: From Bubble Babies to an Approved Drug. 2017

Francesca Ferrua, and Alessandro Aiuti

1 San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), Pediatric Immunohematology and Bone Marrow Transplantation Unit, San Raffaele Scientific Institute , Milan, Italy.

Twenty-five years have passed since first attempts of gene therapy (GT) in children affected by severe combined immunodeficiency (SCID) due to adenosine deaminase (ADA) defect, also known by the general public as bubble babies. ADA-SCID is fatal early in life if untreated. Unconditioned hematopoietic stem cell (HSC) transplant from matched sibling donor represents a curative treatment but is available for few patients. Enzyme replacement therapy can be life-saving, but its chronic use has many drawbacks. This review summarizes the history of ADA-SCID GT over the last 25 years, starting from first pioneering studies in the early 1990s using gamma-retroviral vectors, based on multiple infusions of genetically corrected autologous peripheral blood lymphocytes. HSC represented the ideal target for gene correction to guarantee production of engineered multi-lineage progeny, but it required a decade to achieve therapeutic benefit with this approach. Introduction of low-intensity conditioning represented a crucial step in achieving stable gene-corrected HSC engraftment and therapeutic levels of ADA-expressing cells. Recent clinical trials demonstrated that gamma-retroviral GT for ADA-SCID has a favorable safety profile and is effective in restoring normal purine metabolism and immune functions in patients >13 years after treatment. No abnormal clonal proliferation or leukemia development have been observed in >40 patients treated experimentally in five different centers worldwide. In 2016, the medicinal product Strimvelis™ received marketing approval in Europe for patients affected by ADA-SCID without a suitable human leukocyte antigen-matched related donor. Positive safety and efficacy results have been obtained in GT clinical trials using lentiviral vectors encoding ADA. The results obtained in last 25 years in ADA-SCID GT development fundamentally contributed to improve patients' prognosis, together with earlier diagnosis thanks to newborn screening. These advances open the way to further clinical development of GT as treatment for broader applications, from inherited diseases to cancer.

UI	MeSH Term	Description	Entries
D005822	Genetic Vectors	DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.	Cloning Vectors,Shuttle Vectors,Vectors, Genetic,Cloning Vector,Genetic Vector,Shuttle Vector,Vector, Cloning,Vector, Genetic,Vector, Shuttle,Vectors, Cloning,Vectors, Shuttle
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000243	Adenosine Deaminase	An enzyme that catalyzes the hydrolysis of ADENOSINE to INOSINE with the elimination of AMMONIA.	Adenosine Aminohydrolase,Aminohydrolase, Adenosine,Deaminase, Adenosine
D012190	Retroviridae	Family of RNA viruses that infects birds and mammals and encodes the enzyme reverse transcriptase. The family contains seven genera: DELTARETROVIRUS; LENTIVIRUS; RETROVIRUSES TYPE B, MAMMALIAN; ALPHARETROVIRUS; GAMMARETROVIRUS; RETROVIRUSES TYPE D; and SPUMAVIRUS. A key feature of retrovirus biology is the synthesis of a DNA copy of the genome which is integrated into cellular DNA. After integration it is sometimes not expressed but maintained in a latent state (PROVIRUSES).	Leukemogenic Viruses,Leukoviruses,Oncornaviruses,Oncovirinae,Oncoviruses,Oncoviruses, Type C,RNA Tumor Viruses,Retroviruses,Type C Oncoviruses,C Oncovirus, Type,C Oncoviruses, Type,Leukemogenic Virus,Leukovirus,Oncornavirus,Oncovirus,Oncovirus, Type C,RNA Tumor Virus,Retrovirus,Tumor Virus, RNA,Tumor Viruses, RNA,Type C Oncovirus,Virus, Leukemogenic,Virus, RNA Tumor,Viruses, Leukemogenic,Viruses, RNA Tumor
D015316	Genetic Therapy	Techniques and strategies which include the use of coding sequences and other conventional or radical means to transform or modify cells for the purpose of treating or reversing disease conditions.	Gene Therapy,Somatic Gene Therapy,DNA Therapy,Gene Therapy, Somatic,Genetic Therapy, Gametic,Genetic Therapy, Somatic,Therapy, DNA,Therapy, Gene,Therapy, Somatic Gene,Gametic Genetic Therapies,Gametic Genetic Therapy,Genetic Therapies,Genetic Therapies, Gametic,Genetic Therapies, Somatic,Somatic Genetic Therapies,Somatic Genetic Therapy,Therapies, Gametic Genetic,Therapies, Genetic,Therapies, Somatic Genetic,Therapy, Gametic Genetic,Therapy, Genetic,Therapy, Somatic Genetic
D016511	Severe Combined Immunodeficiency	Group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. It is inherited as an X-linked or autosomal recessive defect. Mutations occurring in many different genes cause human Severe Combined Immunodeficiency (SCID).	Bare Lymphocyte Syndrome,Immunodeficiency, Severe Combined,Omenn Syndrome,Immunodeficiency Syndrome, Severe Combined,Immunologic Deficiency, Severe Combined,Omenn's Syndrome,Reticuloendotheliosis, Familial,Severe Combined Immune Deficiency,Severe Combined Immunodeficiency Syndrome,Severe Combined Immunologic Deficiency,Bare Lymphocyte Syndromes,Combined Immunodeficiencies, Severe,Combined Immunodeficiency, Severe,Familial Reticuloendothelioses,Familial Reticuloendotheliosis,Immunodeficiencies, Severe Combined,Lymphocyte Syndrome, Bare,Lymphocyte Syndromes, Bare,Omenns Syndrome,Reticuloendothelioses, Familial,Severe Combined Immunodeficiencies,Syndrome, Bare Lymphocyte,Syndrome, Omenn,Syndrome, Omenn's,Syndromes, Bare Lymphocyte
D056947	Enzyme Replacement Therapy	Therapeutic replacement or supplementation of defective or missing enzymes to alleviate the effects of enzyme deficiency (e.g., GLUCOSYLCERAMIDASE replacement for GAUCHER DISEASE).	Enzyme Replacement Therapies,Replacement Therapies, Enzyme,Replacement Therapy, Enzyme,Therapies, Enzyme Replacement,Therapy, Enzyme Replacement
D018380	Hematopoietic Stem Cell Transplantation	Transfer of HEMATOPOIETIC STEM CELLS from BONE MARROW or BLOOD between individuals within the same species (TRANSPLANTATION, HOMOLOGOUS) or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). Hematopoietic stem cell transplantation has been used as an alternative to BONE MARROW TRANSPLANTATION in the treatment of a variety of neoplasms.	Stem Cell Transplantation, Hematopoietic,Transplantation, Hematopoietic Stem Cell