Stem Cell Transplantation for Patients With Graft Failure Following an Allogeneic Transplant, Using Identical or Near Identical Donors and Less Toxic Conditioning With CAMPATH 1H

Study participants will receive the following treatment:

Day -5 to -2...Fludarabine 30mg/m2* and CAMPATH** 1H 10mg IV

Day -1.........Day of rest

Day 0..........Stem cell transplant (infusion)

Where possible, patients will receive peripheral blood stem cells. When peripheral stem cells are unavailable (e.g. from some unrelated donor centers) or insufficient, bone marrow will be substituted. If peripheral blood stem cell collection is performed, the donor will be stimulated with G-CSF for 5 days and cells collected and frozen until the stem cell target number is obtained prior to the patient beginning the therapy. If a bone marrow harvest is performed, this will be performed on Day 0 (infusion day). After transplantation, G-CSF 5 micrograms/kg/day will be administered SC from day 7 until granulocytes >1000/ul.

Because CAMPATH-1H infusions will provide a persisting level of antibody over the transplant period, it will contribute to anti-GvHD activity. Additional GVHD prophylaxis will consist of FK506 administered IV via continuous infusion over 24 hours from Day-2 until engraftment or when the patient is able to take by mouth, every 12 hours. This is continued until 6 months post-transplantation. The dose is then tapered every 2 weeks until discontinued. All patients will receive supportive care (prophylaxis for antimicrobial, antiviral, antifungal and Pneumocystis Pneumonia, transfusions of blood products and intravenous gamma globulin and routine laboratory testing of chemistry and complete blood counts) as per Cell and Gene Therapy Standard Operating Procedures (SOP).

Donor engraftment will be evaluated via standard bone marrow studies (cytogenetics/DNA studies for chimerism) on days 30, 60, 100, 180 and 365 post transplantation. If these studies reveal loss of donor cells on two consecutive studies and/or evidence of relapsing disease, the donor will undergo a peripheral blood stem cell harvest via G-CSF stimulation.