Retroviral Mediated Gene Transfer of the Fanconi Anemia Complementation Group C Gene to Hematopoietic Progenitors of Group C Patients
Fanconi anemia (FA) is a rare genetic disorder characterized by progressive pancytopenia,
congenital abnormalities, and predisposition to malignancy. Therapy is currently limited to
allogeneic marrow transplantation; patients lacking a suitable donor usually die from
aplasia or acute leukemia. Recently, mutation in a novel gene named FACC (Fanconi anemia
C-complementing) has been identified as causing one type of FA. FACC mutations, which
introduce splicing errors or stop codons, have been identified in 15% of FA patients. We
have recently been successful in functional complementation of four FA cell lines using
retroviral vectors to transfer a copy of the normal FACC gene. We also analyzed the ability
of four viral vectors to functionally correct hematopoietic progenitor cells from a patient
bearing a splice donor mutation. As for the lymphoid cell lines, these CD34 enriched cells
were extremely sensitive to MMC. After injection of these progenitor cells with viral
vectors bearing normal FACC, the progenitors gave rise to increased numbers of colonies both
in the absence and presence of up to 5 nM MMC, whereas control cells were completely
destroyed by 1 nM MMC. In summary, we have demonstrated that: (1) retroviral vectors can be
engineered to transfer a normal FACC gene to FA(C) lymphoid cell lines and primary
hematopoietic cells; (2) introduction of a normal FACC gene into CD34+ progenitors markedly
enhances their growth in the absence and presence of MMC.
This study is designed to determine whether hematopoietic progenitors transduced with the
normal FACC gene can be re-infused safely into FA(C) patients. CD34+ cells obtained from
G-CSF mobilized peripheral blood will be transduced ex vivo over a 72 hour period in the
presence of IL-3, IL-6, and stem cell factor with the FACC retroviral vector. These
transduced cells will be re-infused into FA(C) patients. Patients will be monitored for
toxicities as well as evidence of successful gene transfer and expression. The procedure
will be repeated up to a total of 4 times with each treatment 2-4 months apart.
Theoretically, these rescued stem cells should have a selective growth advantage within the
hypoplastic FA marrow environment in vivo.
Interventional
Allocation: Non-Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment
United States: Federal Government
940033
NCT00001399
December 1993
February 2009
Name | Location |
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National Institutes of Health Clinical Center, 9000 Rockville Pike | Bethesda, Maryland 20892 |