Stem Cell Transplant Using Peripheral and Cord Blood Stem Cells to Treat Severe Aplastic Anemia and Myelopdysplastic Syndrome

Severe aplastic anemia (SAA) and myelodysplastic syndrome (MDS) are life-threatening bone
marrow disorders. For SAA patients, long term survival can be achieved with immunosuppressive
treatment. However, of those patients treated with immunosuppressive therapy, one quarter to
one third will not respond, and about 50 percent of responders will relapse.

Allogeneic bone marrow transplantation from either HLA-matched sibling or matched unrelated
donor cures about 70 percent of patients with SAA and 30-60 percent of patients with MDS.
Unfortunately, most patients with these disorders are not suitable candidates for
hematopoietic stem cell transplantation (HSCT) due to advanced age or lack of a
histocompatible donor. For such patients, transplantation using unrelated cord blood (UCB)
has been shown to be a reasonable alternative transplant strategy. The advantage to UCB
transplant is the ease and rapidity of availability, requirement of less than perfect HLA
match, and lower rates of graft versus host disease compared to mismatched bone marrow or
peripheral blood stem cell transplants. The major disadvantage of UCB transplantation in
adults is the limited number of nucleated cells contained within the cord unit resulting in
prolonged neutropenia and failure of engraftment which contributes to infection and
transplant related mortality (TRM). In order to harness the advantage of UCB availability and
to overcome the disadvantage of delayed neutrophil recovery, we propose to test whether
co-administration of unrelated umbilical cord blood and a relatively low number of highly
purified haploidentical peripheral blood CD34+ cells from a related donor might promote rapid
engraftment and reduce TRM secondary to prolonged neutropenia associated with conventional
UCBT.

This research protocol is therefore designed to evaluate the safety and effectiveness of
co-infusion of unrelated umbilical cord blood and haploidentical CD34 plus cells from a
related donor following nonmyeloablative conditioning for neutropenic patients with SAA or
MDS with refactory anemia (RA) that has proven to be refractory to medical therapy. Subjects
will receive a novel non-myeloablative immunosuppressive conditioning regimen of
cyclophosphamide, fludarabine, horse ATG and one dose of total body irradiation (200cGy)
followed by an infusion of the allografts. The haploidentical stem cell product will be
T-cell depleted and enriched for CD34 plus cells using the Miltenyi CliniMacs system. To
reduce TRM secondary to prolonged neutropenia associated with conventional UCB
transplantation, haploidentical CD34+ stem cells will be co-infused with a single UCB unit
(serologically matched at greater than or equal to 4/6 HLA loci).

The primary endpoint is donor engraftment by day 42 (defined as an ANC of greater than 500
from either the haplo donor, the cord, or both combined). Secondary endpoints will include
standard transplant outcome variables such as non-hematological toxicities, incidence and
severity of acute and chronic GVHD, and relapse of disease. We will also evaluate ANC
recovery (ANC greater than 500 cells/microl) at day 22, and 100 day and 200 day treatment
related mortality (TRM) of this novel transplant approach. Health related quality of life
will also be assessed pre-transplant 30 and 100 days poste transplant, and every 6 months
until 5 years post transplant.

- INCLUSION CRITERIA - RECIPIENT:

- Diagnosed with severe aplastic anemia characterized by all of the following:

1. Bone marrow cellularity less than 30 percent (excluding lymphocytes)

2. Transfusion dependence for platelets and/or RBCs

3. Neutropenia (absolute neutrophil count less than 500 cells/microL) OR for
patients receiving granulocyte transfusions, absolute neutrophil count < 500
cells/microL before beginning granulocyte transfusions].)

OR

- Diagnosed with myelodysplastic syndrome characterized by refractory anemia OR
refractory anemia with ringed sideroblasts (RARS and at least one of the following:

1. Neutropenia [(absolute neutrophil count < 500 cells/microL) OR for patients
receiving granulocyte transfusions, absolute neutrophil count < 500 cells/microL
before beginning granulocyte transfusions]) and history of 1 or more
opportunistic infections related to neutropenia. OR

2. History of severe aplastic anemia transformed to MDS

- Intolerance of or failure to respond standard immunosuppressive therapy.

- Availability of at least one HLA-haploidentical (i.e. greater than or equal to 5/10
and less than or equal to 8/10 HLA match) related donor (HLA-A, B, C, DR, and DO loci)
who is available to donate CD34+ cells (4-75 years old).

- Availability of at least one 4/6 HLA-matched (HLA-A, B, and DR loci) cord blood unit
from the National Marrow Donor Program (NMDP). The cord blood unit must contain a
minimum TNC (prior to thawing) of at least 1.5 x 10(7) cells per kilogram of recipient
body weight with the following exception: if the minimum criterion of TNC is not met
the cord unit must contain at least 1.7 x 10(5) CD34 plus cells/kg (prior to thawing).

- Ages 4-55 years inclusive.

- Ability to comprehend the investigational nature of the study and provide informed
consent. The procedure will be explained to subjects aged 4-17 years with formal
consent being obtained from parents or legal guardian.

- Telomere Length Testing

- In patients where a suspicion for a familial bone marrow failiure syndromes
(BMFS) exists, TERC and TERT mutation testing will be performed on protocol
04-H-0012 or performed elsewhere prior to enrolling on 04-H-0012.

EXCLUSION CRITERIA - RECIPIENT:

- Availability of an HLA identical or 9/10 HLA matched(HLA A, B, C, DR, and DO
loci-relative to serve as a stem cell donor.

- The patient is deemed to be a candidate for a 6/6 HLA matched unrelated stem cell
transplant (availability of a donor and resources required for such a transplant).

- ECOG performance status of 2 or more.

- Major anticipated illness or organ failure incompatible with survival from transplant

- Severe psychiatric illness. Mental deficiency sufficiently severe as to make
compliance with the transplant treatment unlikely and making informed consent
impossible.

- Positive pregnancy test for women of childbearing age.

- HIV positive

- Diagnosis of Fanconi's anemia (by chromosome breakage study).

- Diffusion capacity of carbon monoxide (DLCO) less than 40 percent using DLCO corrected
for Hgb or lung volumes (patients under the age of 10 may be excluded from this
criterion if they have difficulty performing the test correctly and thus are unable to
have their DLCO assessed) using DL Adj and DL/VA/Adj.

- Left ventricular ejection fraction less than 40 percent (evaluated by ECHO) or less
than 30 percent (evaluated by MUGA)

- Transaminases greater than 5x upper limit of normal (when transaminases are elevated,
the subject may be excluded at the discretion of the PI).

- Serum bilirubin greater than 4 mg/dl

- Creatinine clearance less than 50 cc/min by 24 hr urine collection (adjusted for body
surface area, i.e.50 ml/min/1.73m(2))

- Serum creatinine > 2.5 mg/dl

- Failure to collect an adequate number of CD34+ cells (i.e. greater than or equal 2 x
10(6) CD34+ cells/kg) for transplantation from the subject s haploidentical relative.

- Presence of an active infection not adequately responding to appropriate therapy

- History of a malignant disease liable to relapse or progress within 5 years

INCLUSION CRITERIA - RELATED HAPLOIDENTICAL DONOR DONATING PURIFIED CD34 PLUS CELLS:

- HLA mismatched family donor (greater than or equal to 5/10 and less than or eqhal to
8/10 HLA matched (HLA-A, B, C, DR and DO loci) who is available to donate CD34+ cells.

- Ages 4-75 inclusive

- Weight greater than or equal to 15 kg.

- For adults: Ability to comprehend the investigational nature of the study and provide
informed consent. For minors: Written informed consent from one parent or guardian who
is not the recipient of the transplant and informed assent: The process will be
explained to the minor on a level of complexity appropriate for their age and ability
to comprehend.

- If there is a suspicion of familial BMFS in the recipient, then the donor must have
undergone genetic testing for genes associated with BMFS - performed at a
CLIA-certified laboratory, prior to enrollin in this protocol.

EXCLUSION CRITERIA RELATED DONOR (ANY OF THE FOLLOWING):

- Pregnant or breastfeeding.

- A pediatric haploidentical donor will be excluded if a suitable adult haploidentical
donor is available.

- Unfit to receive filgrastim (G-CSF) and undergo apheresis (history of stroke, MI,
unstable angina, uncontrolled hypertension, severe heart disease or palpable spleen).

- HIV positive (Donors who are positive for HBV, HCV or HTLV I/II, T. cruzi [Chagas] may
be used at the discretion of the investigator following counseling and approval from
the recipient).

- Sickling hemoglobinopathies including HbSS, HbAS, HbSC. Donors with HbAS are
acceptable.

- Severe psychiatric illness. Mental deficiency sufficiently severe as to make
compliance with the BMT treatment unlikely and making informed consent impossible.

- Screening test positive for Chagas disease (Trypanosoma cruzi /T.
cruzi/trypanosomiasis) confirmed by the Center for Disease Control (CDC).