The maintenance of busulphan-induced remissions in chronic granulocytic leukaemia with recombinant interferon alpha-2b

Severe cytopenias associated with the sequential use of busulphan and interferon-alpha in chronic myeloid leukaemia

We describe four patients who developed severe thrombocytopenia which progressed to aplasia after the use of alpha-interferon in maintenance therapy of chronic phase CML after busulphan induction. On reviewing over 400 patients in the MRC CML III trial we found that there is a risk of cytopenia developing after busulphan therapy and a lesser risk of cytopenias developing after alpha-interferon therapy. If the therapies are given in a sequential fashion the risk of cytopenia developing appears to be additive, may be pronounced, and may lead to clinically significant problems. Hydroxyurea alone does not lead to sustained cytopenia. Care should be taken to ensure that counts are stable after the use of busulphan before starting alpha-interferon as maintenance therapy.

Agar capillary clonogenic microassays for cellular immunocytotoxic activities in human leukaemia and lymphoma

Current concepts of immunotherapeutic approaches in leukemias and lymphomas using activated cytotoxic lymphocytes and macrophages are briefly reviewed. Defective cellular immunocytotoxic activities and effects of interleukins and chemotherapeutic drugs thereupon are discussed. In vitro assays to measure lymphokine-activated killer (LAK) and natural killer (NK) cell activities suffer from various problems, depending on the quality of the endpoints. Our clonogenic microassay for LAK cell activity, using agar-containing glass capillaries, avoids some of the potential artifacts and offers several advantages that are discussed. As an example the stimulatory effect of low mafosfamide concentrations on the LAK cell activity versus K562 human myeloid leukemia cells is demonstrated. Thus, our clonogenic LAK microassay provides a valid tool for preclinical screening of immunomodulatory agents.

Initial cytoreduction by mitoxantrone and cytarabine has no impact on the outcome of interferon-alfa-2b therapy in chronic myelogenous leukemia

Eleven previously untreated patients with chronic-phase Philadelphia-chromosome-positive chronic myelogenous leukemia were treated with cytotoxic chemotherapy followed by interferon-alfa-2b (IFN-alpha) maintenance. Initial chemotherapy consisted of three cycles of mitoxantrone 10 mg/m2 on day 1 and 2, and cytarabine 100 mg/m2 daily for 5 d. Complete hematological response was obtained in 9 (82%) patients with moderately associated toxicity. However, cytogenetic responses after three cycles were poor and transient (1 partial suppression and 2 minor suppression of Ph chromosome). Maintenance therapy with IFN-alpha was started in 10 patients at 5 x 10(6) U/m2 daily with dose reduction if hematologic toxicity or severe side-effects occurred. Of 9 evaluable patients treated for more than 3 months, 6 patients maintained a complete hematological response, whereas 1 patient remained in partial remission and 2 patients showed progressive disease. Cytogenetic evaluation showed partial suppression of Ph chromosome in 1 patient, whereas 1 patient had a minor response and 5 patients had no change or evolution of new chromosome abnormalities. As the results are not superior to IFN-alpha treatment alone, it is concluded that initial cytoreduction by mitoxantrone and cytarabine has no impact on the outcome of therapy in CML.