DONOR LEUKOCYTE INFUSIONS ARE EFFECTIVE IN RELAPSED MULTIPLE-MYELOMA AFTER ALLOGENEIC BONE-MARROW TRANSPLANTATION

Donor leukocyte infusions (DLI) can induce sustained remissions in pat ients with acute and chronic myeloid leukemia who relapse after alloge neic bone marrow transplantation (allo-BMT). Also, in multiple myeloma (MM), incidental reports have indicated the existence of a graft-vers us-myeloma effect (GVM) induced by allo-reactive T cells. We performed a retrospective study in a larger group of MM patients to characteriz e better the effect, prognostic factors, and toxicity of this new trea tment modality. Thirteen patients with relapsed MM after allo-BMT were studied. Patients received a total of 29 DLI with T-cell doses rangin g from 1 x 10(6)/kg to 33 x 10(7)/kg. Repetitive courses, sometimes wi th escalated cell doses, were undertaken in case of no response to or relapse after DLI. Eight of 13 patients responded: 4 patients achieved a partial remission and 4 patients achieved a complete remission. Dos e escalation was effective in 3 patients. The time to response was med ian 6 weeks (range, 4 to 10 weeks). Major toxicities were secondary to acute and chronic graft-versus-host disease (GVHD), which occurred in 66% and 56% of all patients and in 87% and 85% of the responders, res pectively. Two responding patients developed fatal BM aplasia. The onl y prognostic factors for response were a T-cell dose greater than 1 x 10(8)/kg and the occurrence of GVHD. Seven of nine patients developing acute GVHD responded, as compared with only 1 response in the 4 patie nts without GVHD and 6 of 7 patients with chronic GVHD responded, wher eas no response was observed in the 5 patients without chronic GVHD. D LI are effective in a high percentage of patients with relapsed MM aft er allo-BMT, although it is associated with a high treatment-related t oxicity. The dose of T cells used may be important in determining the GVM effect, with the highest probability of response after infusion of more than 1 x 10(8) T cells. Because the optimal individual dose may vary, patient-adapted therapy consisting of repeated infusions with es calating dose of donor leukocytes until maximum response is achieved m ay therefore be preferable. (C) 1997 by The American Society of Hemato logy.