Chemotherapy of acute myelocytic leukemia with neuraminidase treated allogeneic leukemic cells

Successful chemoimmunotherapy was previously reported with vibrio cholerae neuraminidase (VCN) treated leukemic cells in the cute of DBA/2 mice with L1210 and AKR mice with spontaneous leukemia. This treatment evokes greater resistance to challenge than any other reported chemotherapy in experimental leukemia. These data led to clinical trial in acute myelocytic leukemia using VCN treated allogeneic myeloblasts. Patients were allocated to 2 groups following successful remission induction using cytosine arabinoside and daunorubicin. All received cyclical maintenance chemotherapy every 4 wk with VCN treated allogeneic myeloblasts; i.d. Immunologic monitoring included recall antigen skin testing, T & B lymphocytes and lymphoblastogenesis. In each immunization 10¹⁰ VCN cells were injected in approx. 50 sites in different node drainage areas. Induration to VCN treated cells at 48 hr was proportional to cell number per site and increased with frequency of immunization, diameters usually exceed 25 mm. In ten patients who received previous antileukemic therapy, 6 immunized patients had more than twice the remission duration of controls. In previously untreated patients the median remission duration on chemotherapy alone was 20 wk for 7 patients, while 5 of 7 patients receiving VCN immunotherapy remain in remission from 56 to 97 wk.