Randomized controlled study of chemoimmunotherapy of acute myelogenous leukemia (AML) in adults withNocardia Rubra cell-wall skeleton and irradiated allogeneic AML cells

Abstract
The effect of immunotherapy with Nocardia rubra cell‐wall skeleton (N‐CWS) on remission duration and survival of adults with acute myelogenous leukemia (AML) was studied in a prospective randomized controlled study. After having been induced into complete remission and having been consolidated, 73 patients were randomized either to maintenance chemotherapy or maintenance chemotherapy plus immunotherapy with N‐CWS and irradiated allogeneic AML cells. Thirty‐four patients in the chemotherapy group and 32 in the chemoimmunotherapy group were evaluable. Six months after the closure of the study, the immunotherapy showed a borderline beneficial effect on remission duration (P = 0.080) and on survival length (P = 0.098). When the data were analyzed at 30 months after the entry, there was a borderline significant difference in remission duration (P = 0.080) between the two groups, prolonging the 50% remission period by 110 days; but no significant difference in survival length (P = 0.314), although the 50% survival was 168 days longer in the chemoimmunotherapy group. However, there were 4 (18.2%) 5‐year relapse‐free survivors among 22 patients (11 in each group) who had been diagnosed more than 5 years before the time of the present analysis, and all of them belonged to the chemoimmunotherapy group (P = 0.090). Thus, immunotherapy with N‐CWS and irradiated allogeneic AML cells seems to be active in the treatment of adult AML when used for maintenance therapy in combination with chemotherapy. Cancer 57:1483–1488, 1986.