Pentostatin and Lymphocyte Infusion in Preventing Graft Rejection in Patients Who Have Undergone Donor Stem Cell Transplant

PRIMARY OBJECTIVES: I. To assess the safety and efficacy of the combined use of pentostatin and donor lymphocyte infusion (DLI) in patients with low or falling donor T-cell chimerism to prevent graft rejection after transplantation both from matched related donors (MRDs) or unrelated donors (URDs). SECONDARY OBJECTIVES: I. To determine the incidence of graft-versus-host disease (GvHD) infections and disease response, if persistent disease is present. OUTLINE: This is a dose-escalation study of donor lymphocyte infusion. GROUP I: Patients receive pentostatin intravenously (IV) over 20-30 minutes on day -2 and DLI over 15-30 minutes on day 0. Treatment may repeat once beginning with an escalated or same cluster of differentiation (CD)3-dose at least 4 weeks if persistent donor T-cells are documented, no GvHD has developed, and the chimerism status worsens or, if chimerism status is unchanged after at least 8 weeks with two subsequent tests of chimerism 4 weeks apart. GROUP II (initiated if patients in group I do not achieve sustained engraftment and improved chimerism): Patients receive treatment as in group I. Patients also receive cyclosporine orally (PO) twice daily (BID) on days -3 to 56 and mycophenolate mofetil PO once daily (QD) on days 0 to 27. Treatment continues in the absence of GvHD. After completion of study treatment, patients are followed up every 6 months for 2 years and then annually thereafter.