Pentostatin, Cyclophosphamide, and Rituximab Followed By Campath-1H in Patients With Relapsed or Refractory B-Cell CLL

OBJECTIVES: Primary * Determine the objective response rate (complete remission, partial remission \[PR\], or nodular PR) in patients with relapsed or refractory B-cell chronic lymphocytic leukemia (CLL) treated with pentostatin, cyclophosphamide, and rituximab (PCR) followed by CAMPATH-1H . * Determine the presence of minimal residual disease in patients treated with this regimen who achieve a CR or nPR Secondary * Determine the toxicity of this regimen in these patients. * Determine the overall and progression-free survival of patients treated with this regimen. * Evaluate the number of patients who after PCR (or during PCR for PD), only achieve a PR, SD, or PD and who subsequently convert to a higher response category after CAMPATH-1H . Exploratory * Assess the angiogenic profile (i.e., secretion levels of pro- versus anti-angiogenic molecules) of CLL B cell clones as well as bone marrow angiogenesis (i.e., vascular density by immunohistochemistry) at baseline, after PCR, after CAMPATH-1H, every six months (serum only), and at time of response assessment (marrow). * Determine the V\_H gene mutation status and CD38 expression of the B-CLL clones at study entry and at the end of the therapy and assess the association between the VH gene mutation status and CD38 expression and clinical outcome. * Determine surface phenotype (by flow cytometry) and genetic defects (by CLL FISH panel) information on CLL-B cell clones and associate with clinical outcome. * Monitor the T-cell status by repertoire and flow cytometry analysis to determine the nature and extent of T-cell deficiency induced by the PCR and CAMPATH-1H treatment and assess any association with clinical outcome and toxicities.