Chemoimmunotherapy with levamisole in acute lymphoblastic leukemia

Patients with acute lymphoblastic leukemia (ALL) who were in two consecutive protocols and in complete remission (CR) with maintenance therapy, were randomized to receive or not receive levamisole. A total of 15 of 55 low‐risk patients of protocol 10‐LLA‐72 with levamisole had relapses, compared with 25 of 54 not receiving levamisole; 67 and 49%, respectively, remain in CR at 48 months (P < 0.025). In protocol 1‐LLA‐76, 14 of 91 low‐risk patients on levamisole and 25 of 93 patients not receiving levamisole had relapses; 78 and 61%, respectively, remain in CR at 36 months (P < 0.05). Seventeen of 39 high‐risk patients (children with a leukocyte count higher than 50,000 and adults) receiving levamisole had relapses compared with 37 of 61 not on levamisole. The DNCB skin test shows at 18 and 24 months a 74 and 85% positivity in the levamisole group vs. a 38 and 35% positivity in the control group (P< 0.025). We conclude that levamisole prolongs the duration of CR and survival in low‐risk patients with ALL.