Lymphodepleting effects and safety of pentostatin for nonmyeloablative allogeneic stem-cell transplantation.
Nonmyeloablative allogeneic stem-cell transplantation (alloNST) is the focus of investigations searching for less-toxic transplantation regimens. We report studies on the kinetics of lymphodepletion and safety of pentostatin (PT) conditioning in alloNST. Patients with hematologic malignancy received mobilized blood from human leukocyte antigen-matched related (n=4) or unrelated (n=8) donors. PT 4 mg/m2 was administered on days -21, -20, and -19 and 200 cGy of total-body irradiation was administered on day -1, followed by cyclosporine A and mycophenolate mofetil. Mononuclear cell adenosine deaminase after PT was inhibited 84%. The absolute CD3+ cells decreased significantly by day -7 (49%) and CD19+ cells declined 92% by day -1. CD4+ cells were depressed more than CD8+ cells. Neutrophils and monocytes were minimally affected by PT. Median posttransplant peripheral blood chimerism on day 70 showed 95% donor leukocytes and 82.5% donor CD3 lymphocytes. PT demonstrated lymphodepleting effects and promising safety, supporting alloNST as early as 7 days after initiation of PT.
D000328:Adult; D000368:Aged; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects*; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects*; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects; D015649:Pentostatin / Q000008:administration & dosage*; D010865:Pilot Projects; D033581:Stem Cell Transplantation; D014184:Transplantation, Homologous
D007166:Immunosuppressive Agents; D015649:Pentostatin