This is a clinical trial of gene therapy for X-linked severe combined immunodeficiency (XSCID), a genetic disease caused by defects in a protein called the common gamma chain, which is normally on the surface of immune cells called lymphocytes. XSCID patients cannot make T lymphocytes, and their B lymphocytes fail to make essential antibodies for fighting infections. Without T and B lymphocytes patients develop fatal infections in infancy unless they are rescued by a bone marrow transplant from a healthy donor. However, even transplanted patients may achieve only partial immune recovery and still suffer from many infections, auto-immunity and/or and poor growth. A recent, successful trial in France used gene therapy instead of bone marrow transplantation for infants with XSCID. This experience indicates that gene therapy can provide clinical benefit to XSCID patients. We will enroll six older XSCID patients (2-20 years-old_, who have previously received at least one bone marrow transplant, but still have poor T and B lymphocyte function that compromises their quality of life. Before enrollment, these subjects will have had some of their own blood-forming stem cells harvested and frozen in a blood bank. These cells have a defective gene, but a correct copy of the gene will be inserted while the cells are grown in sterile conditions outside the patient's body. To do this, the cells will be unfrozen and exposed for four days in a row to growth factors and particles of a retrovirus we have constructed and tested called "GALV MFGS-gc." Retrovirus particles will attach to the patient cells and introduce a correct copy of the common gamma chain gene into cells capable of growing into all types of blood cells, including T and B ymphocytes. Each XSCID patient enrolled in the study will receive a single dose of his own cells that have been modified by the GALV MFGS-gc treatment. After this, the patients will be monitored to find out if the treatment is safe and to see if their immune function improves. Study endpoints are (1) efficient and safe clinical-scale correction of cells from XSCID patients; (2) administration of treated cells to six subjects: and (3) year follow-up of the treated subjects to see how many of their cells have taken up the correct copy of the gene, how many new T and B lymphocytes express a normal common gamma chain, and whether the patients' immune function and general health improve.

Condition	Treatment or Intervention	Phase
Severe Combined Immunodeficiency	Drug: Gamma Chain Transduced CD34+ Cells	Phase I

Further Study Details: 

Expected Total Enrollment:  6

This is a Phase I/II clinical trial of ex vivo hematopoietic stem cell (HSC) gene therapy for X-linked severe combined immunodeficiency (XSCID). XSCID results from defects in the IL2RG gene encoding the common gamma chain (gc) shared by receptors for Interleukin 2 (IL-2), IL-4, IL-7, IL-9, IL-15 and IL-21. XSCID patients generally lack T-lymphocytes and NK cells, and their B-lymphocytes fail to make essential antibodies. XSCID is fatal in infancy without immune reconstitution, such as by allogeneic bone marrow transplantation (BMT). However, many transplanted patients achieve only partial immune reconstitution, and consequently have recurrent infections, autoimmunity and/or poor growth. Recent successful retroviral gene therapy instead of BMT for infants with XSCID indicates that ex vivo gene therapy can provide clinical benefit to XSCID patients, although leukemia occurred in two of the treated patients indicating that there are significant risks with gene therapy.

We will enroll six older XSCID patients (2-20 years-old; greater than or equal to 15 kg body weight), who have had attempted BMT, but who have persistent T-lymphocyte and B-lymphocyte impairments that compromise their quality of life. Prior to enrollment, each case will be presented for review and risk/benefit assessment by the IRB and regulatory agencies. These subjects will have had autologous CD34+ HSC mobilized by treatment with granulocyte colony stimulating factor (G-CSF), collected from peripheral blood by apheresis, immune selected and cryopreserved in sufficient numbers to achieve entry criteria (greater than or equal to 1.0 x 10(6) CD34+ HSC/kg body weight). HSC procurement will be conducted under a separate, approved and active NIH protocol, 94-I-0073, 'Recruitment of peripheral blood hematopoietic progenitors by granulocyte colony stimulating factor [G-CSF]'.

Autologous CD34+ HSC will be subjected to four daily transductions ex vivo with the gibbon ape leukemia virus (GALV) envelope-pseudotyped, replication-defective, murine onco-retrovirus vector, MFGS-gc that encodes the common gamma chain. Transductions will occur in flexible gas-permeable plastic containers using serum-free medium supplemented with 1% human serum albumin and five recombinant growth factors (50 ng/ml Flt3-L, 50 ng/ml SCF, 50 ng/ml TPO, 25 ng/ml IL-6, and 5 ng/ml IL-3). Each subject will receive a single infusion of transduced HSC. Subjects will be monitored for safety and efficacy; the latter evidenced by new development of autologous transduced lymphocytes with functional gc. Study endpoints are (1) efficient and safe clinical-scale transduction of HSC from post-BMT XSCID subjects; (2) administration of transduced HSC to six subjects; and (3) 3 year follow up of treated subjects to monitor vector sequence distribution, gc expression in hematopoietic lineages, and lymphocyte numbers and function; as well as general health and immune status.

Genders Eligible for Study:  Both

Criteria

INCLUSION CRITERIA:
Patients must have XSCID as defined by either a deleterious mutation in IL2RG, the absence of or less than 5% of normal detectable gc protein, or evidence of functionally defective gc protein.
Patients must be between 2 and 20 years of age.
Patients must weigh at least 15 kg.
Patients will have evidence of combined B-cell and T-cell immune deficiency over at least a 6 month period despite previous allogeneic BMT at least 18 months prior to study entry. T-cell immune deficiency is defined as one or more of the following: Total T-cell count less than 500/ul; less than 50% of normal value for in vitro mitogen stimulation; or absent proliferation in vitro to antigens. B-cell immune deficiency is defined as one or more of the following: IgM, IgA or IgE values which are 2 or more standard deviations below the established value for normal, IgG values falling to less than 30% of normal during unintended interruptions or delay in the periodic administration of IVIG; or documented failure to respond to a specific antigen challenge.
Patients must less than or equal to 3% of their mobilized CD34+ cells deriving from their allogeneic bone marrow donor.
EXCLUSION CRITERIA:
Any current or preexisting hematologic malignancy.
Current treatment with any chemotherapeutic agent.
Current treatment with any immunosuppressive agent, excluding corticosteroids.
Documented HIV-1 infection.
Documented Hepatitis B infection.
Childhood malignancy (occurring before 18 years of age) in the patient or a first degree relative, or known genotype of the subject conferring a predisposition to cancer.

Maryland
      National Institute of Allergy and Infectious Diseases (NIAID), 9000 Rockville Pike,  Bethesda,  Maryland,  20892,  United States; Recruiting

Study ID Numbers:  020057; 02-I-0057
Record last reviewed:  December 23, 2004
Last Updated:  December 30, 2004
Record first received:  December 17, 2001
ClinicalTrials.gov Identifier:  NCT00028236
Health Authority: United States: Federal Government
ClinicalTrials.gov processed this record on 2005-04-08