THE USE OF A SEQUENTIAL HIGH-DOSE RECOMBINANT INTERLEUKIN-2 REGIMEN AFTER AUTOLOGOUS BONE-MARROW TRANSPLANTATION DOES NOT IMPROVE THE DISEASE-FREE SURVIVAL OF PATIENTS WITH ACUTE-LEUKEMIA TRANSPLANTED IN FIRSTCOMPLETE REMISSION

We report the outcome of 50 consecutive patients with CRI acute leukem ia (AML = 22; ALL = 28) treated with autologous BMT, after cyclophosph amide and TBI, followed with a sequential high dose rIL2 regimen. rIL- 2 (RU 49637 from Roussel-Uclaf, Romainville, France) was started after hematological reconstitution an average of 72 +/- 22 days post trans plant. The schedule consisted of a continuous infusion over 5 cycles ( Cycle i: 5 days starting on day 1; cycle 2-5: 2 days starting on day 1 5, 29, 43 and 57). Patients were treated at 4 different dosages (12 (N = 40), 16 (N = 3), 20 (N = 2), 24 (N = 5) x 10(6) IU/m2/day). Toxicit ies were mainly related to capillary leak syndrome and thrombocytopeni a. Patients received an average of 122 +/- 49 10(6) IU/m(2). Two patie nts with AML died from toxicity. rIL-2 infusion was associated with ve ry a high level of immune stimulation of both T-cells (P < 0.05) and n atural killer (NK) cells (P < 0.05) and associated cytolytic functions (P < 0.05). With a minimal and median follow-up of 21 and 46 months, 3 year leukemia free survival is 41 +/- 6% overall, 39 +/- 10% and 43 +/- 8% for AML and ALL respectively. Relapse probabilities at 3 years are 59 +/- 11% for AML and 57 +/- 8% for ALL. We conclude that this sh ort infusion of rIL-2 over 2 months, resulting in an increased immune stimulation, is not associated with a better leukemic control for pati ents with acute leukemia transplanted early after reaching first compl ete remission.