Chemotherapy of acute myelogenous leukaemia

Low-dose combination chemotherapy for acute myeloid leukemia in elderly patients: a novel approach

Eighteen patients aged 60-84 years with acute myeloid leukemia were treated with low-dose combination chemotherapy comprising cytarabine, etoposide, and mitozantrone or 6-thioguanine; seven of these patients had a pre-existing myelodysplastic syndrome. Nine patients achieved a complete remission, and five had a partial remission. The duration of survival in these 14 responding patients has ranged from 2+ to 19+ months. Myelotoxicity occurred regularly, with time to recovery (neutrophils > or =0.5 x 10(9)/L, platelets > or =50 x 10(9)/L) from nadir being 10-14 days in 12 of the 14 patients. This novel approach with an overall response rate of 78% appears to be a simple and effective form of therapy for elderly patients.

Evaluation of carboplatin as a single agent in highly refractory acute myeloid leukemia

Thirteen patients (pts) with highly refractory acute myeloid leukemia (AML) 10 pts with de novo AML and 3 with blast crisis of chronic myeloid leukemia were treated with carboplatin (CP) 150 mg/m2/day through continuous IV infusion for 7 consecutive days. Seven of them received CP at least as third or more line therapy after a median duration of the disease of 26 weeks. None achieved a complete remission but a good hematologic response, with disappearance of circulating blast cells along with correction of bone marrow failure, persisting for 3 months was obtained in one patient and correction of hyperbasophilemia was observed in another with blast crisis of chronic myelogenous. Myelosuppression was the most consistent toxic effect. Two deaths occurred, one from renal acute failure and the other from sepsis. Median survival after CP was 8 weeks (range 4 days-11 months) and the majority of patients were able to return home. When used as a single agent and with the dose-schedule used in this study, CP does not appear effective in refractory AML. Other studies are necessary to assess its role at an higher dose or in combination with other agents in earlier phases of the disease.

Clinical significance of P-glycoprotein expression in acute leukaemia as analysed by immunocytochemistry

Multidrug resistance, mediated by the overexpression of an energy-dependent transport protein, P-glycoprotein, has been one of the major targets of interest in solving the mechanisms of clinical drug resistance of malignant cells. To evaluate the correlation between P-glycoprotein overexpression and the response to chemotherapy, we analysed cytospin preparations of gradient-separated blood or bone marrow mononuclear cells from 79 patients with acute leukaemia by means of the P-glycoprotein-directed monoclonal antibody JSB-1 and immunocytochemistry using the alkaline phosphatase-antialkaline phosphatase technique. P-glycoprotein expression was detected in all disease phases of acute leukaemia. Thirteen out of 51 patients at diagnosis, 10/29 patients in relapse or during residual disease and 8/27 patients in remission overexpressed P-glycoprotein. Seven out of the 8 positive remission samples were collected between the cycles of consolidation treatment. Our results suggest that increased P-glycoprotein expression in samples collected between the cycles of consolidation treatment during remission may be induced in normal leukocytes by cytotoxic drug treatment, infections, or by some physiological mechanisms related to the disease. Patients older than 45 years of age were significantly more often P-glycoprotein-positive (11/25) at diagnosis than younger patients (2/26). P-glycoprotein expression at diagnosis was significantly correlated with a low remission rate after the first cycle of induction therapy. Of 34 P-glycoprotein-negative patients, 25 achieved remission after the first cycle as compared to 4/12 of the P-glycoprotein-positive patients. Our results indicate that the method used is specific and sensitive enough for the analysis of P-glycoprotein expression and that the expression at initial presentation is inversely correlated with the outcome of induction therapy.