Mismatched Donor Lymphocyte Infusions for Relapsed Disease Following Allogeneic Stem Cell Transplantation

Patients receiving allogeneic stem cell transplantation for hematological malignancies who
suffer a relapse of their disease post-transplant have limited treatment options and a poor
prognosis. With the exception of patients with chronic leukemias who may achieve prolonged
remissions after donor lymphocyte infusions (DLIs), treatments using either chemotherapy or
a DLI achieve less than a 10% median survival beyond 6 months. Most of these patients die of
progressive leukemia, underlying the need for new therapeutic approaches.

HLA-mismatched DLIs appear to possess a more potent graft-versus-leukemia (GvL) effect.
However, when given after an HLA-mismatched transplant DLIs have a high risk of causing
graft-versus-host disease (GvHD), which can be severe. To reduce the risk of GvHD, infusions
of mismatched lymphocytes from an alternative donor may be used to avoid permanent
engraftment and associated risk of GvHD.

In this study, we propose to use a novel strategy to treat leukemias relapsing after HLA
matched allogeneic stem cell transplantation by using haplo-identical DLIs to promote the
associated antileukemic effect while minimizing the possibility of permanent engraftment and
associated GvHD. To achieve only temporary engraftment and to promote disease control we
will give fludarabine immunosuppression prior to the DLI. We anticipate the infusion of
HLA-mismatched donor lymphocytes in this setting will produce no detectible engraftment or
only temporary engraftment, but may result in a strong GvL effect regardless of engraftment
outcome. We will select patients for this protocol who fall into the worst category for
post-transplant relapse. Specifically, we will enroll patients with acute leukemia or MDS
relapsing within 6 months of transplant, of which less than 5% survive beyond a year from
relapse.

The primary objective of this phase II clinical trial will be to evaluate the safety and
efficacy of using a non-engraftment model and a lymphocytes infusion from a haplo-identical
donor to treat relapsed disease following matched sibling stem cell transplantation in
subjects who are not candidates for alternative treatment options.

We therefore propose this is a phase II clinical trial is to evaluate the safety and
efficacy of an infusion of unmanipulated lymphocytes from a haplo-identical donor in
subjects with relapsed disease following matched sibling stem cell transplantation who are
not candidates for alternative treatment options.

The primary endpoint of this phase 2 study is survival at 6 month post-relapse of disease.
Successful outcome of the study will be a survival of 100% greater than the National Heart
Lung and Blood (NHLBI) historical 25% at 6-months.

Secondary endpoints will include: incidence and severity of induced GvHD, proportion of DLI
engraftment, peak chimerism, leukemia response at 21 days post DLI, residual leukemia
measured by patient chimerism, leukemia free survival from date relapse, and safety of the
mismatched DLI procedure.

- ELIGIBILITY CRITERIA:

Inclusion Criteria- Recipient:

1. Diagnosed with one of the following hematological conditions:

- Acute lymphoblastic leukemia (ALL) of any subtype or

- Acute myelogenous leukemia (AML) of any subtype or

- Myelodysplastic syndrome (MDS) of any subtype or

- Blastic phase CML

2. Relapsed disease within 6 months of matched sibling allogeneic stem cell transplant
procedure

3. Evaluation for protocol within 8 weeks of relapse and enrollment within 12 weeks or
relapse

4. 8-75 years of age

5. Availability of previous HLA identical (6/6) related donor (ages 8 to 17 must have
previously donated bone marrow [not peripheral blood]

6. At least one haploidentical (1-3 antigen mismatched) related donor available for
apheresis

Exclusion Criteria Recipient (any of the following):

1. Active grade II-IV GvHD

2. Extensive chronic GvHD

3. Post-transplant DLI from original donor within 1 month of protocol enrollment.

4. Progressive disease despite post-relapse chemo or monoclonal therapy.

5. Co-morbidity of such severity that it would preclude the patient s ability to
tolerate protocol therapy.

6. AST/SGOT greater than 10 x ULN (grade 3, CTCAE).

7. Bilirubin greater than 5 x ULN (grade 3, CTCAE).

8. Creatinine greater than 3.5 mg/dl (grade 3, CTCAE).

9. HIV positive (Recipients who are positive for hepatitis B (HBV), hepatitis C (HCV) or
human T-cell lymphotropic virus (HTLV-I/II) are not excluded from participation).

10. Positive pregnancy test for women of childbearing age.

11. Severe psychiatric illness or mental deficiency sufficiently severe as to make
compliance with the transplant treatment unlikely and informed consent impossible.

Inclusion Criteria- Stem Cell Donors:

1. HLA-matched sibling stem cell donor from the original transplant to participate in a
stem cell rescue only in the setting of severe, refractory GvHD caused by the
haploidentical cells.

2. Related HLA haplo-identical (1-3 A, B or DR antigens mismatched with recipient). To
maximize the GvL that is associated with HLA disparity, the haploidentical donor will
be chosen based on the greatest HLA mismatch (preference: 3/6 greater than 4/6
greater than 5/6). Parents and siblings will be considered equally.

3. Weight greater than or equal to 18 kg

4. Age greater than or equal to 8 or less than or equal to 80 years old.

Exclusion Criteria Stem Cell Donor (any of the following):

1. Pregnant or lactating

2. Unfit to receive filgrastim (G-CSF) or previous filgrastim mobilization for donors
under 18 years of age.

3. Unfit to undergo apheresis (abnormal blood counts, history of stroke, uncontrolled
hypertension).

4. Sickling hemoglobinopathies such as HbSS or HbSC.

5. HIV positive. Donors who are positive for hepatitis B (HBV), hepatitis C (HCV), human
T-cell lymphotropic virus (HTLV-I/II), or T.cruzi (Chagas) will be used at the
discretion of the investigator following counseling and approval from the recipient.

6. Severe psychiatric illness or mental deficiency sufficiently severe as to make
compliance with the donation of stem cells unlikely and/or informed consent
impossible.

Inclusion criteria- Haplo Lymphocyte Donors:

1. Related HLA haplo-identical (1-3 A, B or DR antigens mismatched with recipient). To
maximize the GvL that is associated with HLA disparity, the haploidentical donor will
be chosen based on the greatest HLA mismatch (preference: 3/6 greater than 4/6
greater than 5/6). Donors age less than 80 years required, and parents and siblings
will be considered equally.

2. Age greater than or equal to 18 or less than or equal to 80 years old.

Exclusion Criteria Haplo Lymphocyte Donor (any of the following):

1. Pregnant or lactating

2. Unfit to undergo apheresis (abnormal blood counts, history of stroke, uncontrolled
hypertension).< TAB>

3. Sickling hemoglobinopathies such as HbSS and HbSC .

4. HIV positive. Donors who are positive for hepatitis B (HBV), hepatitis C (HCV) or
human T-cell lymphotropic virus (HTLV-I/II), or T.cruzi (Chagas) will be used at the
discretion of the investigator following counseling and approval from the recipient.

5. Severe psychiatric illness or mental deficiency sufficiently severe as to make
compliance with the donation of stem cells unlikely and/or informed consent
impossible