Fludarabine-Based Conditioning for Allogeneic Marrow Transplantation in Aplastic Anemia

Your bone marrow normally produces white cells, red cells, and platelets. Once ready, these
cells are released into the bloodstream. Aplastic anemia is a blood disorder where the bone
marrow has stopped working and produces very few or no cells to be released into the
bloodstream. If not successfully treated, this condition will almost always lead to death,
primarily because of infection or bleeding. A bone marrow transplant is an option for you
because your doctors believe it may cure your aplastic anemia. As you do not have a matched,
sibling donor, a matched, unrelated donor (i.e. not a blood relative) has been selected for
you. Before you receive a matched, unrelated donor marrow transplant, you will receive
medications and low dose total body irradiation (TBI) to kill immune cells in your body that
might reject the cells from your donor. This will allow your body to accept the donor marrow.
This is called engraftment.

Cyclophosphamide is a medication that will be used in this study to lower your immune system
in order to allow your body to accept the donor marrow cells.

If you are found eligible to take part in this study, you will be given medications and TBI
before your bone marrow transplant to allow your body to accept your donor's stem cells. This
is called the conditioning regimen. Before your transplant, a catheter (i.e. a soft plastic
tube) will be inserted into a vein under the collarbone to allow for medications and fluids
to be given.

The conditioning regimen includes a combination of drugs used to kill the cells in your body
that may reject the donor cells. The drugs to be used in this study are fludarabine,
cyclophosphamide, and ATG, as well as low-dose to TBI. All participants in this study will
receive the same amount of fludarabine, ATG and low-dose TBI. You will receive fludarabine on
the fifth, fourth, third and second days before your transplant by intravenous infusion
through your catheter over about 30 minutes.

You will receive ATG on the fourth, third, and second days before your transplant. This will
be given intravenously through your catheter over 4 to 6 hours. ATG is an animal product, and
your study doctor may decide to use a horse or a rabbit product. Both products have similar
side effects and efficacy. You will receive TBI on the day before your transplant.

Different groups of patients will get different amounts of cyclophosphamide. You will receive
cyclophosphamide for a total of either 1 or 2 days before your transplant. The number of days
depends on your group. You will be placed in the group that is being tested at that time.
Your doctor will tell you which group you are in. Neither you nor your doctor can choose the
group. Sometimes there may be a short waiting period for a new patient to be entered in the
study, and you should discuss with your doctor how this waiting period may affect you.

The main purpose of this study is to find the best dose of cyclophosphamide. This means that
small groups of patients are treated with a given dose of cyclophosphamide and followed
closely until it can be shown that the new marrow has been accepted by the body and the
treatment has not caused any unacceptable harm. In the early part of the study, participants
were receiving cyclophosphamide for either 3, 2, 1 or 0 days. The doctors who are conducting
the study have by now gained some experience with this conditioning schedule, and this has
helped them to narrow down the number of possible doses of cyclophosphamide that you, as a
new participant, may receive. You should be aware that some participants who received 3 days
of cyclophosphamide (the highest dose) suffered severe side effects (including death), and
therefore, new patients are no longer being placed in this group. You should also be aware
that participants who received zero days of cyclophosphamide (the lowest dose) experienced
graft rejection (meaning, their body did not accept the new marrow, and the new cells failed
to grow). Therefore, new participants are no longer being assigned to this group.
Participants who now come to transplantation will be treated with either 1 or 2 days of
cyclophosphamide.

After the conditioning regimen, the donor marrow cells will be given to you through your
catheter. The cells will travel into the bloodstream to reach your bone marrow where they are
expected to make healthy, new blood cells. This step is necessary to replace your diseased
marrow and because the high dosages of drugs given to you during the conditioning regimen may
also damage or destroy healthy cells in your bone marrow. Until the new cells begin producing
healthy blood cells, you will be at an increased risk of bleeding or developing an infection.

Following the transplant (at least every week until roughly 100 days after transplant, then
every 3-6 months for 2 years after that), you will have a complete medical history and
physical exam, including measurement of height and weight. Blood (about 2-4 tablespoons) and
urine may be collected for routine tests. You will also have a bone marrow aspiration and
biopsy at 30 and 100 days after transplant and then every 4-6 months for 2 years after that.

You will be expected to take medications such as cyclosporine (or tacrolimus) by mouth for no
less than 6-9 months to prevent graft-versus-host disease. You will also be expected to stay
at the transplant center for at least 3 months after your transplant. You will be asked to
return to the transplant center for regular follow-up care. The standard tests will be done
at that time.

You will be in the study for up to 2 years. Follow-up for transplant will last as long as you
require care. However, researchers would like to keep track of your medical condition for the
rest of your life by contacting you and the doctor providing your regular medical care by
phone or mail once a year. Keeping in touch with you and checking on your condition every
year helps researchers to look at the long-term effects of the study and transplantation in
general. It is not necessary for you to agree to follow-up for longer than 2 years to
participate in this study. After 2 years, you will continue to be followed by your transplant
doctor, but no longer as part of the study.

You can be taken off the study (with or without your consent) for several reasons. You may be
taken off study if you no longer meet the study requirements. Ask you doctor if you would
like more information about this. You can be taken off study if you need a medical treatment
not allowed in this study, or the study chair decides that it would be in your best interest
to leave the study. You may be taken off study if intolerable side effects occur. You will be
taken off study if your transplant fails to take. In this case, your doctor will decide what
the best treatment for you will be. You may be taken off study if you are unable to follow
study instructions or keep study appointments. You may also be taken off study if the study
is stopped by the Food and Drug Administration (FDA) or the National Institutes of Health
(NIH).

This is an investigational study. All of the drugs and medications used in this study are
FDA-approved and commercially available.

Up to 94 participants will be enrolled in this multicenter study. Up to 9 will be enrolled at
MD Anderson.

Inclusion Criteria:

1. Patients up to 65 years of age at time of registration with a diagnosis of severe
aplastic anemia (SAA). SAA is defined as follows: - Bone marrow cellularity < 25%, or
marrow cellularity < 50% but with < 30% residual hematopoietic cells. Two out of three
of the following (in peripheral blood): neutrophils < 0.5 x 10^9/L; platelets < 20 x
10^9/L; reticulocytes < 20 x 10^9/L. SAA diagnostic criteria may be applied to
assessment at initial diagnosis or to the follow-up assessments.

2. Patient must have an available unrelated donor with a 7/8 or 8/8 match for HLA-A, B, C
and DRB1 antigen. Typing is by DNA techniques: intermediate resolution for A, B and C,
and high resolution for DRB1. HLA-DQ typing is recommended but will not count in the
match

3. Patient and/or legal guardian able to provide signed informed consent.

4. Matched unrelated donor must consent to provide marrow allograft.

5. Patients with adequate organ function as measured by: a) cardiac: left ventricular
ejection fraction at rest must be > 40% or shortening fraction > 20% b) hepatic: serum
total bilirubin < 2x upper limit of normal for age as per local laboratory; ALT and
AST < 4x upper limit of normal for age as per local laboratory; c) renal: serum
creatinine < 2x upper limit of normal for age (as per local laboratory). d) pulmonary
forced expiratory volume at one second (FEV1), forced vital capacity (FVC) and
diffusing capacity of lung for carbon monoxide (DLCO) (corrected for Hb) > 50%
predicted. For pts where pulse oxymetry is performed, O2 saturation > 92%

6. The diagnosis of Fanconi anemia must be excluded in patients younger than 18 years of
age by diepoxybutane (DEB) testing on peripheral blood or comparable testing or
marrow.

Exclusion Criteria:

1. Clonal cytogenetic abnormalities associated with myelodysplastic syndrome (MDS) or
acute myeloblastic leukemia (AML) on marrow examination.

2. Diagnosis of other "congenital" aplastic anemias such as: Diamond-Blackfan;
Shwachman-Diamond; congenital megakaryocytosis.

3. Symptomatic or uncontrolled cardiac failure or coronary artery disease.

4. Karnofsky performance status < 60% or Lansky < 40% for patients < 16 years of old.

5. Uncontrolled bacterial, viral or fungal infections (currently taking medication and
progression of clinical symptoms). Patients with fevers despite broad-spectrum
antimicrobials but no clinical or hemodynamic evidence of sepsis will be allowed.

6. Seropositive for the human immunodeficiency virus (HIV).

7. Pregnancy (positive ß-HCG) or breastfeeding.

8. Presence of large accumulation of ascites or pleural effusions, which would be a
contraindication to the administration of methotrexate for graft-versus-host disease
(GVHD) prophylaxis.

9. Known severe or life-threatening allergy or intolerance to ATG or
cyclosporine/tacrolimus.

10. Planned administration of alemtuzumab (Campath-1H) or other investigational agents as
alternative agent for GVHD prophylaxis.

11. Concomitant enrollment in a Phase I study.

12. Positive patient anti-donor lymphocyte crossmatch in HLA-A or B mismatched transplants
(test recommended but not mandatory). The definition of match is in Section 2.2.1.

13. Prior allogeneic marrow or stem cell transplantation.

14. Patients with prior malignancies except resected basal cell carcinoma or treated
carcinoma in-situ. Cancer treated with curative intent < 5 years previously will not
be allowed unless approved by the Medical Monitor or Protocol Chair. Cancer treated
with curative intent > 5 years previously will be allowed.