A PILOT-STUDY OF BUSULFAN AND MELPHALAN AS PREPARATORY REGIMEN PRIOR TO ALLOGENEIC BONE-MARROW TRANSPLANTATION IN REFRACTORY OR RELAPSED HEMATOLOGICAL MALIGNANCIES

In this pilot study, we assessed the immunosuppressive and the antileu kemic potential of a combination of busulfan and melphalan prior to al logeneic BMT in 25 adult patients,vith refractory or relapsed hematolo gical malignancies. Twelve patients were transplanted for acute myeloi d leukemia (relapse: five patients; primary refractory: four patients; second remission: two patients), two patients for primary refractory acute lymphoblastic leukemia, nine patients for chronic myelogenous le ukemia (accelerated phase: six patients; blastic phase: three patients ) and two patients for primary refractory lymphoma. All received an un manipulated marrow from HLA-identical siblings. All patients but one e ngrafted (median time to ANC greater than or equal to 0.5 x 10(9)/l = 17 days, to platelets greater than or equal to 50 x 10(9)/l = 29 days) , Full chimerism was documented in the seven evaluable patients. The p robability for developing acute GVHD was 58%, Complete remission was o btained in 17/18 measurable patients. With a 42 month median follow-up , eight patients are alive in ummaintained remission. The 4-year proba bilities for relapse, survival, and DFS are respectively: 42%, 35%, an d 31%. These results show that the combination of busulfan and melphal an ensures an effective immunosuppression allowing long-term engraftme nt. This regimen can provide long-term disease-free survival in patien ts with high-risk disease and thus represents an interesting alternati ve to the CY and/or TBI-containing regimens.