Chemoimmunotherapy with Corynebacterium parvum in acute myelocytic leukemia

Central nervous system involvement in acute nonlymphocytic leukemia. A prospective study of adults in remission

To identify adults with acute nonlymphocytic leukemia at risk for the development of central nervous system involvement, we performed periodic cerebrospinal fluid examinations on patients in remission. Among 58 consecutive patients monitored during first remission, central nervous system leukemia developed in nine (16 percent). Four patients, including one who was symptomatic, had central nervous system leukemia detected simultaneously with marrow relapse. Five additional patients were asymptomatic and continue to have bone marrow remission. Following central nervous system and systemic treatment, two of these five patients have never had relapse, and three had relapse in the bone marrow five, 10, and 21 months later. Factors at diagnosis associated with the subsequent development of central nervous system leukemia were elevated leukocyte count, serum lysozyme and lactate dehydrogenase, extramedullary infiltration including splenomegaly, and monocytic (FAB M4 or M5a) morphology. In six of 17 patients (35 percent) with monocytic morphology, central nervous system leukemia developed compared with only three of 41 patients (7 percent) with other subtypes (p = 0.02). Discriminant analysis identified leukocyte count, splenomegaly, and M4 or M5a morphology as the most important risk factors and led to a mathematical formula that correctly identified 90 percent of the patients. Although the risk of central nervous system leukemia in adults with acute nonlymphocytic leukemia is too low to justify routine prophylaxis, those patients recognized to be at a greater risk should receive prophylaxis or be monitored closely with periodic lumbar punctures.

Treatment of acute nonlymphocytic leukemia in young and elderly patients

Among 95 consecutive patients with acute nonlymphocytic leukemia (ANLL), 61 were treated with a high-dose chemotherapeutic induction regimen consisting of daunorubicin, vincristine, and cytosine arabinoside (DOA). The complete remission (CR) rate was 66%. Although young patients responded better than older patients, only sex was found to be of prognostic significance for achieving CR (84% CR in men versus 47% in women, P less than 0.005, independent of age). Patients in CR received consolidation, monthly maintenance therapy, and late intensification for a period of 2 years. Median remission duration was 57 weeks and median survival, 93 weeks. Projected CR rate at 5 years was 30%. CR and survival duration were significantly longer in patients 40 to 60 years old when compared with younger and older patients (P = 0.023). They were also longer in male than in female patients (P = 0.018), but this may be due to an effect of age. In the 34 patients who did not receive DOA treatment because of age or poor clinical conditions, there was no survival beyond 57 weeks, except in a 73-year-old woman who reached a spontaneous remission during acute infection. ANLL characteristics at presentation revealed a tendency toward a smaller tumor mass (P less than 0.05) and rarer Auer rods present (P = 0.03) with increasing age. Features and treatment of ANLL in elderly patients are discussed in view of the poor results obtained with conservative management.

Immunotherapy in the treatment of acute myelogenous leukemia (AML): rationale, results and future prospects

Patients with AML in complete remission (CR) are immunosuppressed; remission lymphocytes of at least a part of the patients are able to recognize autologous leukemic blasts; the CR represents a minimal residual disease. Thus, important conditions for a potentially successful active immunotherapy are given. Results of most earlier randomized trials on immunotherapy revealed some, but limited benefit with respect to survival. Encouraging effects, however, have been achieved by immunizing CR patients with high-dose neuraminidase-treated allogeneic blasts. Because these data have not been confirmed until now we recently initiated a randomized study utilizing identical treatment protocols. The preliminary results of the ongoing study still do not allow to draw any firm conclusions. Specific monoclonal antibodies or autologous cytotoxic T-cells may be useful tools for future immunotherapy of AML.

Adjuvant immune stimulation with Corynebacterium parvum during maintenance chemotherapy of acute myeloid leukemia. A prospective randomized study

Of 93 consecutively treated patients with acute myeloid leukemia 36 (39%) achieved complete remission (CR). Thirty-five patients were randomized to receive either maintenance chemotherapy alone (C) or a combination of active nonspecific immunotherapy with Corynebacterium parvum and chemotherapy (C + I). Maintenance therapy was given monthly for 1 year or until relapse. The median survival time was 21 months for patients treated with chemotherapy alone, compared with 30 months for patients treated with chemotherapy and immunotherapy. The median remission duration was 15 months for patients treated with chemotherapy, compared with 18 months for chemotherapy and immunotherapy group. While no statistically significant difference in remission duration or survival time could be attributed to the use of immune stimulation, a plateau of 40% long-term time survivors was defined in the chemotherapy and immunotherapy group. Age and sex were found to be the major prognostic factors for achievement of CR. No difference was found in remission duration or survival between the two different induction schedules. Neither did the morphological subtype of AML (FAB classification) or the leukocyte count at diagnosis correlate with remission rate or survival.

Immunotherapy maintenance in acute non-lymphocytic leukaemia

Between January 1975 and December 1977, 264 adult patients with acute non-lymphocytic leukaemia entered the Australian National Leukaemia Trial. Of 251 evaluable patients, three induction regimens achieved similar complete response (CR) rates. CROP (cytosine arabinoside, daunorubicin, vincristine, prednisolone) produced CR in 41% of patients, 7 and 3 (cytosine arabinoside, daunorubicin) in 42% and 7 and 3 plus hydroxyurea in 52%. Remission duration and survival were similar when induction regimens were compared. Forty-five patients reaching maintenance therapy were randomised to either chemo-immunotherapy (BCG plus intradermal leukaemic blast cells) or chemotherapy alone. The duration of CR in these two groups was almost identical, though patients receiving chemotherapy alone had prolonged survival (median 161 weeks) when compared to the chemo-immunotherapy group (84 weeks, p = 0 . 07). Institutions with less developed supportive facilities reported lower CR rates (p = 0 . 04). Leucocytosis (greater than 100 X 10(9)/1) and older age (greater than 50 years) were associated with shortened survival. The Trial has failed to show any advantage for this form of immunotherapy.

Controversies in the therapy of acute myelogenous leukemia

In the past 10 years, there has been substantial progress in the treatment of patients with acute myelogenous leukemia. Intensive induction chemotherapy and consolidation chemotherapy have increased complete remission rates from 25 percent to more than 70 percent and have extended median survival from six months to more than two years. Attempts to prolong remission with maintenance chemotherapy, immunotherapy, and central nervous system prophylaxis have been less successful. Recent data suggest that the use of intensification chemotherapy or bone marrow transplantation in patients in remission may further reduce or eliminate residual leukemia. As a result of one or more of these advances an increasing proportion of patients, up to 25 percent in some series, are alive and free of disease three to five years following diagnosis. Most data indicate that some of these patients may be cured. In this article, we review the therapeutic interventions responsible for this substantial increase in survival in what was previously a uniformly fatal disease. Recent advances are discussed as are controversies in management and future directions.

Maintenance chemoimmunotherapy of nonlymphoblastic acute leukemias

A trial of maintenance chemotherapy of nonlymphoblastic acute leukemia led to a comparison of two groups of patients in complete remission. Group 1 (14 patients) received only monthly reinduction chemotherapy. Group 2 (17 patients) received identical chemotherapy together with weekly immunotherapy combining BCG and irradiated leukemic cells. While the duration of the first complete remission was unmodified, the overall survival time and, above all, survival after the first relapse were prolonged in group 2 chemoimmunotherapy. These results were all the more marked when a homogeneous group of patients having received the same induction chemotherapy were considered.

Augmentation of natural killer (NK) cell activity by a streptococcal preparation, OK-432, in patients with malignant tumors

Recently, a streptococcal preparation, OK-432 has been used successfully as an immunopotentiator for immunotherapy in patients with malignant tumors in Japan. In this paper, we report that the administration of OK-432 augments the cytotoxic activity of peripheral blood lymphoid cells against a natural killer (NK) cell-sensitive erythroleukemic cell line, K562, in tumor patients. In patients before or after surgery, sufficient amounts of OK-432 strongly augmented the cytotoxic activity within 3 days after the initial administration of OK-432. Thereafter the levels of cytotoxicity declined rapidly. The administration of a lower dose of OK-432 gave a lower increase in cytotoxicity. Enhanced cytotoxicity occurred with the reintroduction of OK-432 but remained at lower levels of activity. Characterization and fractionation of OK-432-induced effector cells revealed that the augmented cytotoxicity seemed to be carried mainly by NK cells. A low titer of interferon was detected in 3 of 10 patients within 72 hr after the first inoculation of the agent. Furthermore, we discuss the potency of OK-432 for the induction of interferon in detail.