The role of immunotherapy in acute myelogenous leukemia.

The use of immunotherapy for acute myelogenous leukemia (AML) is controversial. Twenty-four trials have been reported in which 1,491 patients with AML received various forms of immunotherapy, including BCG, methanol extract residue (MER) of BCG, or Corynebacterium parvum. Some patients were immunized with allogeneic or autologous leukemia blast cells. In only four of the 24 trials was a significant prolongation of remission reported. Pooled data from all 24 studies were analyzed further. No statistically significant difference in duration of remission between patients who received maintenance chemotherapy alone and those who received maintenance chemotherapy plus immunotherapy was found. A significant survival advantage for those patients who received BCG and chemotherapy for maintenance therapy was detected. A beneficial biologic effect for the patients treated with BCG is suggested but this was not a disease-free survival advantage, and had no impact on cure of patients with AML. Immunotherapy, as currently conceived, seems to have no substantial benefit for patients with AML receiving optimal chemotherapy.