Treatment With Recombinant Interferon (a-2P) Early After Bone Marrow Transplantation in Patients at High Risk for Relapse

Relapse continues to be a problem after bone marrow transplantation (BMT) for hematologic malignancies, particularly in recipients of autologous or T-cell-depleted allogeneic grafts and in patients with advanced disease. Interferon (IFN) has shown antiproliferative activity in several malignant hematologic diseases and potentially may be of benefii when administered early after BMT when the number of residual cells is minimal. We tested in a phase I study the maximum tolerated daily dose of recombinant IFN ~ 2 b in patients who had received a transplant for a disease at high risk for relapse (acute myeloid leukemia or non-Hodgkin’s lymphoma beyond first remission, advanced myelodysplastic syndrome, acute lymphoblastic leukemia at any stage, chronic myeloid leukemia in accelerated or blast phase. Recombinant IFN a-2b was started at a dose of 0.5 x 10’ IU/m2 and escalated by 0.5 x lo6 IU/m2 in groups of three or four patients. The intention was to administer IFN as soon as stable engraftment after BMT was achieved (defined as an absolute neutrophil count of >2.0 x 109/L and platelet count > 100 x 10°/L for 5 consecutive days) and continued for 2 months. A total of 14 patients were enrolled after autologous (n = 3) or allogeneic (n = 11) BMT. Dose-limiting toxicity was myelosuppres-