Gene Therapy for Fanconi Anemia

PRIMARY OBJECTIVES:

I. To determine the safety of lentiviral gene transfer for patients with Fanconi anemia
complementation group A.

SECONDARY OBJECTIVES:

I. To determine the feasibility and efficacy of filgrastim (G-CSF) and plerixafor
mobilization in FA patients.

II. To determine the feasibility and efficacy of lineage depletion of bone marrow or
mobilized apheresis product.

III. To determine the transduction efficiency for human FA patient hematopoietic progenitor
cells transduced with a clinical grade lentiviral vector encoding the gene for Fanconi anemia
complementation group A.

IV. To determine if gene transfer using the clinical grade vector will result in phenotypic
correction of gene modified cells by in vitro assays.

V. To determine if infusion of FANCA gene-modified cells will result in engraftment and
persistence of gene-modified cells and improvement in blood counts in FA patients.

OUTLINE:

STEM CELL MOBILIZATION FOR CELL COLLECTION: Patients receive filgrastim subcutaneously (SC)
twice daily (BID) for 5-6 days (on days 1-6 of mobilization). Patients receive plerixafor SC
once daily (QD) on days 4-6 of mobilization. Peripheral blood stem cell (PBSC) count will be
checked daily starting on day 4 of mobilization. Patients who have a PBSC count of >= 5 CD34+
cells/mcL will undergo up to 2 apheresis collections on consecutive days.

BONE MARROW HARVEST FOR CELL COLLECTION: Patients with inadequate PBSC counts undergo bone
marrow harvest for collection of stem/progenitor cells.

REINFUSION: Patients receive methylprednisolone intravenously (IV) or prednisone orally (PO)
on days -1 to 7 followed by a rapid taper over approximately 1 week and undergo reinfusion of
genetically modified hematopoietic stem/progenitor cells on day 0.

After completion of study treatment, patients are followed up periodically for 15 years.

Inclusion Criteria:

- FA demonstrated by a positive test for increased sensitivity to chromosomal breakage
with mitomycin C or diepoxybutane performed by a Clinical Laboratory Improvement
Amendments (CLIA) or College of American Pathologists (CAP) approved laboratory

- FA complementation group A as determined by somatic cell hybrids, molecular
characterization, western blot analysis, acquisition of mitomycin C resistance after
in vitro lentiviral transduction with a vector bearing the complementary
deoxyribonucleic acid (cDNA) for Fanconi complementation group A, or other clinically
certified method of complementation group analysis

- Bone marrow analysis demonstrating normal cytogenetics, and no more than 5% of cells
with a single clonal abnormality by fluorescence in situ hybridization (FISH) for
myelodysplastic syndrome (MDS) panel within 3 months of stem cell collection

- Signed informed consent by the patient or legally authorized representative

- Absolute neutrophil count >= 0.5 x 10^9/L

- Hemoglobin >= 8 g/dL

- Platelet count >= 20 x 10^9/L and able to achieve a platelet count of >= 50 x 10^9/L
with transfusion support

- Adequate hepatic function with aspartate aminotransferase (AST) and alanine
aminotransferase (ALT) < 5 x upper limit of normal (ULN)

- Adequate renal function with creatinine (Cre) =< 1.5; if greater, then glomerular
filtration rate (GFR) > 60 mL/min/1.73 m^2 as calculated by the Modification of Diet
in Renal Disease equation

- Adequate pulmonary function with corrected diffusion capacity of carbon monoxide
(DLCO) > 50% in those for whom this study can be performed

- For subjects < 17 years of age, Modified Lansky Play-Performance Score of >= 70%; for
subjects 17 and older, Karnofsky score of >= 70%

Exclusion Criteria:

- Non-hematopoietic malignancy where the expected survival is less than 2 years

- Myelodysplastic syndrome as defined by World Health Organization (WHO) criteria

- Acute myeloid leukemia as defined by WHO criteria

- Pregnancy or lactation; females of childbearing potential and males who are admitted
to the study will be advised that the study procedures and study drugs may be
teratogenic, and they will be required to take adequate measures to prevent conception
for the duration of the study

- Concurrent enrollment in any other study using an investigational drug

- Physical or emotional status that would prevent informed consent, protocol compliance,
or adequate follow-up

- Patients for whom an human leukocyte antigen (HLA) matched sibling donor bone marrow
transplant is being actively pursued will not be eligible for study until it is
determined that no sibling donor is available or that a stem cell transplant is not
feasible during the time the patient might be on study

- No patient will be included in this study as an alternative to a clinically
indicated HLA matched sibling donor stem cell transplant

- If an HLA matched sibling donor is identified, but stem cell or marrow collection
is not feasible (e.g., donor is in utero, is a newborn from whom cord blood was
not collected, or is unable to undergo a donation procedure because of ill
health), a patient may be included in the study at the discretion of the
investigators

- Significant associated diseases including documented human immunodeficiency virus
(HIV) infection, uncontrolled hypertension (diastolic blood pressures > 95%ile for
age), unstable angina, congestive heart failure (> New York [NY] class II), poorly
controlled diabetes (hemoglobin A1c [Hgb A1c] > 7%), coronary angioplasty within 6
months, myocardial infarction within the last 6 months, or uncontrolled atrial or
ventricular cardiac arrhythmia, abnormal coagulation, persistent abnormal urinalysis
reflecting intrinsic renal disease

- Active ongoing viral, bacterial, or fungal infection