title: PEG-ADA: an alternative to haploidentical bone marrow transplantation and an adjunct to gene therapy for adenosine deaminase deficiency.
abstract: PEG-ADA is a long-circulating form of adenosine deaminase (ADA) that has been in use for > 8 years as replacement therapy for severe combined immunodeficiency disease due to ADA deficiency. Treatment with PEG-ADA almost completely corrects metabolic abnormalities, allowing the recovery of a variable degree of immune function. Although not normal, the level of function achieved has in most cases been sufficient to protect against opportunistic and life-threatening infections. PEG-ADA has been used as an alternative for patients who lack an HLA-identical bone marrow donor, but are judged to be at too high a risk for undergoing HLA-haploidentical marrow transplantation. To date, mortality and morbidity with PEG-ADA have been less than for the latter procedure. PEG-ADA has also been an important adjunct to attempts to develop somatic cell gene therapy for ADA deficiency, although its continued use poses a problem for evaluation of the benefit of gene therapy. As a true "orphan drug" developed to treat a very small patient population, the cost per patient of PEG-ADA is very high.
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Hershfield
mesh_terms: D000243:Adenosine Deaminase / Q000737:chemistry / Q000172:deficiency* / Q000494:pharmacology*; D000293:Adolescent; D000328:Adult; D016026:Bone Marrow Transplantation; D002648:Child; D015316:Genetic Therapy; D006239:Haplotypes; D006801:Humans; D007223:Infant; D016511:Severe Combined Immunodeficiency / Q000188:drug therapy / Q000235:genetics / Q000628:therapy*
chemical_list: D000243:Adenosine Deaminase; C051409:pegademase bovine