RESUMO
Loss of adenosine deaminase activity leads to severe combined immunodeficiency (ADA-SCID); production and function of T, B, and natural killer (NK) cells are impaired. Gene therapy (GT) with an autologous CD34+-enriched cell fraction that contains CD34+ cells transduced with a retroviral vector encoding the human ADA cDNA sequence leads to immune reconstitution in most patients. Here, we report short- and medium-term safety analyses from 18 patients enrolled as part of single-arm, open-label studies or compassionate use programs. Survival was 100% with a median of 6.9 years follow-up (range, 2.3 to 13.4 years). Adverse events were mostly grade 1 or grade 2 and were reported by all 18 patients following GT. Thirty-nine serious adverse events (SAEs) were reported by 15 of 18 patients; no SAEs were considered related to GT. The most common adverse events reported post-GT include upper respiratory tract infection, gastroenteritis, rhinitis, bronchitis, oral candidiasis, cough, neutropenia, diarrhea, and pyrexia. Incidence rates for all of these events were highest during pre-treatment, treatment, and/or 3-month follow-up and then declined over medium-term follow-up. GT did not impact the incidence of neurologic/hearing impairments. No event indicative of leukemic transformation was reported.
Assuntos
Adenosina Desaminase/deficiência , Adenosina Desaminase/genética , Agamaglobulinemia/genética , Agamaglobulinemia/terapia , Terapia Genética , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/terapia , Adenosina Desaminase/administração & dosagem , Adenosina Desaminase/imunologia , Adenosina Desaminase/metabolismo , Agamaglobulinemia/imunologia , Agamaglobulinemia/metabolismo , Autoimunidade , Criança , Pré-Escolar , Terapia Combinada , Terapia de Reposição de Enzimas , Seguimentos , Expressão Gênica , Terapia Genética/efeitos adversos , Terapia Genética/métodos , Vetores Genéticos/administração & dosagem , Vetores Genéticos/genética , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Lactente , Masculino , Fenótipo , Imunodeficiência Combinada Severa/imunologia , Imunodeficiência Combinada Severa/metabolismo , Transgenes , Resultado do TratamentoRESUMO
Adenosine deaminase (ADA) deficiency is a rare, autosomal-recessive systemic metabolic disease characterized by severe combined immunodeficiency (SCID). The treatment of choice for ADA-deficient SCID (ADA-SCID) is hematopoietic stem cell transplant from an HLA-matched sibling donor, although <25% of patients have such a donor available. Enzyme replacement therapy (ERT) partially and temporarily relieves immunodeficiency. We investigated the medium-term outcome of gene therapy (GT) in 18 patients with ADA-SCID for whom an HLA-identical family donor was not available; most were not responding well to ERT. Patients were treated with an autologous CD34(+)-enriched cell fraction that contained CD34(+) cells transduced with a retroviral vector encoding the human ADA complementary DNA sequence (GSK2696273) as part of single-arm, open-label studies or compassionate use programs. Overall survival was 100% over 2.3 to 13.4 years (median, 6.9 years). Gene-modified cells were stably present in multiple lineages throughout follow up. GT resulted in a sustained reduction in the severe infection rate from 1.17 events per person-year to 0.17 events per person-year (n = 17, patient 1 data not available). Immune reconstitution was demonstrated by normalization of T-cell subsets (CD3(+), CD4(+), and CD8(+)), evidence of thymopoiesis, and sustained T-cell proliferative capacity. B-cell function was evidenced by immunoglobulin production, decreased intravenous immunoglobulin use, and antibody response after vaccination. All 18 patients reported infections as adverse events; infections of respiratory and gastrointestinal tracts were reported most frequently. No events indicative of leukemic transformation were reported. Trial details were registered at www.clinicaltrials.gov as #NCT00598481.