6625 Background: NMT have been reported to have less toxicity than standard allografts, although they still pose a substantial risk of GVHD. We used Campath –1H (C1H) in an attempt to reduce this risk. Methods: Patients (pts) received fludarabine 120 mg/m2, one fraction of total body irradiation 200cGy and a total dose of C1H 100 mg. After progressive loss of chimerism in 5/6 patients (with 3/5 having simultaneous disease progression), the protocol was amended to decrease the C1H dose to 50 mg. Pts received cyclosporine post transplant. Leukemia pts were required to have <10% marrow blasts. Results: We evaluated 13 pts with hematologic malignancies (6 acute myeloid leukemia, 3 myelodysplasia, 1 chronic myeloid leukemia, 1 nonHodgkin's lymphoma, and 2 Hodgkin's.) Median age was 57 yrs (34 –71). Median time to engraftment (neutrophil count 500/ul., platelet count 20,000/ul.) was 19 days (9 - 30.) After protocol amendment, pts achieved chimerism with 90–100 % donor cells by day 100. 4 pts had active disease (1MDS, 1AML,1HD,1NHL) at transplant and progressed post transplant. 3 pts relapsed (2 AML, 1CML) but 1 subsequently achieved a complete remission with a donor lymphocyte infusion (DLI). 6 pts achieved a sustained remission post transplant. 5 pts had DLI; 2 to treat active disease and 3 because of loss of donor chimerism . GVHD occurred in 4 pts; Gr 1–1; Gr 2–3; Gr 3–1. 1 post transplant lymphoproliferative EBV positive plasma cell dyscrasia and 1 EBV viremia occurred. Both also had disease progression and died. Six of 12 pts had CMV viremia that cleared with antiviral therapy. Eight of 12 pts are alive with a median followup of 161 days (47–528). Conclusions: Nonmyeloablative transplantation using C1H at a total dose of 50 mg. is well tolerated and favors donor engraftment. No grade 4 GVHD occurred. DLI helped to convert mixed to full chimerism and to treat relapsed disease. CMV shedding occured in 50% of these transplants but was easily treated with pre–emptive strategies.This approach for the management of hematologic malignancies warrants further evaluation. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Amgen