Patients and Methods: Fifteen patients were studied. Six patients were in advanced refractory relapse, and induction therapy had failed in two patients. Patients with CLL or low-grade lymphoma received fludarabine 90 to 150 mg/m(2) and cyclophosphamide 900 to 2,000 mg/m(2). patients with intermediate-grade lymphoma or in Richter's transformation received cisplatin 25 mg/m(2) daily for 4 days; fludarabine 30 mg/m2; and cytarabine 500 mg/m(2) daily for 2 days. Chemotherapy was followed by allogeneic stem-cell infusion from HLA-identical siblings. Patients with residual malignant cells or mixed chimerism could receive a donor lymphocyte infusion of 0.5 to 2 x 10(8) mononuclear cells/kg 2 to 3 months posttransplantation if graft-versus-host disease (GVHD) was not present.

Results: Eleven patients had engraftment of donor cells, and the remaining four patients promptly recovered autologous hematopoiesis. Eight of 11 patients achieved a complete response (CR). Five of six patients (83.3%) with chemosensitive disease continue to be alive compared with two of nine Patients (22.2%) who had refractory or untested disease at the time of study entry (P = .04).

Conclusion: These findings indicate the feasibility of allogeneic hematopoietic transplantation with a nonablative preparative regimen to produce engraftment and GVL against lymphoid malignancies. The ability to induce remissions with donor lymphocyte infusion in patients with CLL, Richter's, and low-grade and intermediate-grade lymphoma is direct evidence of GVL activity against these diseases. This approach appears to be most promising in patients with chemotherapy-responsive disease and low tumor burden. J Clin Oncol 16:2817-2824. (C) 1998 by American Society of Clinical Oncology.