Randomized study of recombinant interleukin-2 after autologous bone marrowtransplantation for acute leukemia in first complete remission

Immunological control of acute leukemia may be achieved after allogeneic tr ansplant. Despite promising preliminary results, the impact of immunotherap y with interleukin-2 (r-IL-2) on patients with acute leukemia (AL), in firs t complete remission (CR1) remains unclear. We conducted a prospective mult icenter randomized trial to compare outcome in patients with AL in CR1, tre ated with autologous bone marrow transplantation (BMT) with or without post graft r-IL-2, One hundred and thirty patients with AL in CR1 (myeloblastic (AML): N = 78; lymphoblastic (ALL): N = 52) were randomized at time of BMT to receive (N = 65) or not (N = 65) r-IL-2, r-IL-2 (RU 49637 from Roussel U claf) was started after hematological recovery, as a five cycle regimen (12 M IU/m(2)/day continuous infusion on day 1-5, 15-17, 29-31,43-45 and 57-59 ), The two groups were balanced for patient and transplant characteristics. Analysis was based on an intent to treat, Thirty-eight (59%) of the 65 pat ients randomized into the study group started r-IL-2 at a median of sixty-e ight days (23-140) after transplant and received 77% (16-100) of the schedu led dosage, They received a median of 120 x 10(6) IU/m(2) (25-156) over 10 (3-13) days during a total median period of 56 (3-78) days, With a median f ollow-up of 7 years (5.4-8.1 years), 79 patients relapsed (study group: 43 (66%); control group: 36 (55%): p = NS), Survival and leukemia-free surviva l estimates were 33% (23-45) versus 43% (22-52) and 29% (19-41) versus 36% (24-51) respectively for study and control groups (all p = NS), These resul ts show that leukemic control after autologous BMT is not increased by r-IL -2 therapy Further studies should investigate more appropriate r-IL-2 sched ules and the possibilities offered by better antigen recognition and activa ted effector cells.