AUTOLOGOUS STEM CELL TRANSPLANTATION FOR NEWLY DIAGNOSED FOLLICULAR LYMPHOMAS: LOW TOXICITY AND EXTENDED PROGRESSION FREE SURVIVAL. R1235 Barcelona, Spain. Bone Marrow Transplantation March 2004, Volume 33, Supplement 1

In spite of an indolent course, advanced stage follicularlymphomas (FL) are incurable with conventional chemotherapy.High dose therapy could be investigated in selected patients,provided toxicity were acceptable. Improvements in supporttherapy and the widespread use of peripheral blood stem cells(SC) have made autologous transplantation a relatively safeprocedure. This prompted us to start a pilot study and, since1995, 23 patients have been enrolled at our center. Median agewas 49 (26 - 65). Most patients (80%) had stage IV disease andbone marrow involvement. For patients who achieved a completeresponse or a good partial response after CHOP, SC weremobilized with cyclophosphamide or DHAP plus G-CSF, andhigh dose therapy consisted of BEAM. High risk patients or poorresponders (residual high tumor burden or bone marrowinfiltration >50%) switched to a program of high dose sequentialtherapy. Nine patients received not-manipulated hematopoieticSC, 7 received ''ex vivo'' purged SC (6 by CD34+ positiveselection; 1 by positive+negative selection), and 8 patientsunderwent ''in vivo'' purging with anti-CD20 monoclonal antibody(rituximab). Residual disease was monitored at different steps bynested PCR. Treatment was well tolerated, with a median time toengrafment of 9 days (7-12), and a median stay in hospital of 22days (15-35). RBC and platelet transfusions were necessary,respectively, in 52% and 100% of the patients. The meannumber of RBC and platelet units given to transfused patientswas, respectively, 2.2 (1-5) and 3.7 (1-7). Fever occurred in 52%of the patients (mean 2,8 days in febrile patients) and mucositisin 85%. We did not observe, so far, any case of myelodysplasiaor secondary cancer. With a median FU of 58 (8-95) monthsfrom transplant, all patients are alive, 5 have relapsed, and 5-years estimated PFS is 70%. CD34+ selection had no impact onrelapse. In one patient, molecular response could be restoredand maintained by rituximab alone. Only a few data have beenpublished regarding autologous transplantation in FL patients atdiagnosis. Although the FU is relatively short and the number ofpatients still small, the present data suggest that autologoustransplant is a safe and effective therapy for selected, not heavilypretreated young patients with advanced stage disease.Especially since ''in vivo'' purging strategies can easily be carriedout, autologous SC transplantation should be investigated inrandomized trials.