A new regimen of amsacrine with high-dose cytarabine is safe and effective therapy for acute leukemia

Biology and management of relapsed acute myeloid leukaemia

Disease relapse remains the major cause of treatment failure in adults with acute myeloid leukaemia (AML). This reflects both the failure of current salvage regimens and the absence of effective strategies to secure long-term disease-free survival in those patients who achieve a second remission. Recent progress in understanding the pathogenesis of relapsed disease has enabled the identification of a variety of dysregulated molecular pathways and these now provide a rational basis for the design of novel targeted therapies. At the same time, advances in allogeneic stem-cell transplantation have permitted the extension of the curative potential of allografting to patients in whom it was previously contraindicated. As a result, a range of novel drug and transplant therapies has become available in patients with relapsed AML, and it is realistic to anticipate that a co-ordinated assessment of their clinical and biological impact will provide the basis for the design of future, more effective treatments in relapsed disease.

Proposed criteria for classification of acute myeloid leukemia in dogs and cats

Blood and bone marrow smears from 49 dogs and cats, believed to have myeloproliferative disorders (MPD), were examined by a panel of 10 clinical pathologists to develop proposals for classification of acute myeloid leukemia (AML) in these species. French-American-British (FAB) group and National Cancer Institute (NCI) workshop definitions and criteria developed for classification of AML in humans were adapted. Major modifications entailed revision of definitions of blast cells as applied to the dog and cat, broadening the scope of leukemia classification, and making provisions for differentiating erythremic myelosis and undifferentiated MPD. A consensus cytomorphologic diagnosis was reached in 39 (79.6%) cases comprising 26 of AML, 10 of myelodysplastic syndrome (MDS), and 3 of acute lymphoblastic leukemia (ALL). Diagnostic concordance for these diseases varied from 60 to 81% (mean 73.3 +/- 7.1%) and interobserver agreement ranged from 51.3 to 84.6% (mean 73.1 +/- 9.3%). Various subtypes of AML identified included Ml, M2, M4, M5a, M5b, and M6. Acute undifferentiated leukemia (AUL) was recognized as a specific entity. M3 was not encountered, but this subclass was retained as a diagnostic possibility. The designations M6Er and MDS-Er were introduced where the suffix "Er" indicated preponderance of erythroid component. Chief hematologic abnormalities included circulating blast cells in 98% of the cases, with 36.7% cases having >30% blast cells, and thrombocytopenia and anemia in approximately 86 to 88% of the cases. Bone marrow examination revealed panmyeloid dysplastic changes, particularly variable numbers of megaloblastoid rubriblasts and rubricytes in all AML subtypes and increased numbers of eosinophils in MDS. Cytochemical patterns of neutrophilic markers were evident in most cases of Ml and M2, while monocytic markers were primarily seen in M5a and M5b cases. It is proposed that well-prepared, Romanowsky-stained blood and bone marrow smears should be examined to determine blast cell types and percentages for cytomorphologic diagnosis of AML. Carefully selected areas of stained films presenting adequate cellular details should be used to count a minimum of 200 cells. In cases with borderline diagnosis, at least 500 cells should be counted. The identity of blast cells should be ascertained using appropriate cytochemical markers of neutrophilic, monocytic, and megakaryocytic differentiation. A blast cell count of > 30% in blood and/or bone marrow indicates AML or AUL, while a count of < 30% blasts in bone marrow suggests MDS, chronic myeloid leukemias, or even a leukemoid reaction. Myeloblasts, monoblasts, and megakaryoblasts comprise the blast cell count. The FAB approach with additional criteria should be used to distinguish AUL and various subtypes of AML (Ml to M7 and M6Er) and to differentiate MDS, MDS-ER, chronic myeloid leukemias, and leukemoid reaction. Bone marrow core biopsy and electron microscopy may be required to confirm the specific diagnosis. Immunophenotyping with lineage specific antibodies is in its infancy in veterinary medicine. Development of this technique is encouraged to establish an undisputed identity of blast cells. Validity of the proposed criteria needs to be substantiated in large prospective and retrospective studies. Similarly, clinical relevance of cytomorphologic, cytochemical, and immunophenotypic characterizations of AML in dogs and cats remains to be determined.

A phase II study of high dose ARA-C and mitoxantrone for treatment of relapsed or refractory adult acute lymphoblastic leukemia

PURPOSE

The Southwest Oncology Group performed a Phase II study to investigate the effectiveness of an induction regimen of high dose cytosine arabinoside (ara-C) with high dose mitoxantrone for treatment of relapsed or refractory adult acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Patients at least 16-years-old with ALL that was in relapse after, or was refractory to, standard induction therapy including at least vincristine and prednisone were eligible, as long as they had no prior treatment with high dose ara-C. The induction regimen included high dose ara-C (3 g/m2 by 3-h i.v. days 1-5) and mitoxantrone (80 mg/m2 by 15-30 min i.v. 12-20 h after the first dose of ara-C). The study design called for a maximum of 55 patients, with early termination if less than nine of the first 30 achieved complete remission.

RESULTS

Thirty-three patients entered the study, and 31 were included in the analysis. All 31 completed one course of induction therapy. Four patients died of infection and a fifth of cardiomyopathy with possible sepsis. Seven patients achieved complete remission (23%; 95% confidence interval 10-41%). One of the seven received syngeneic bone marrow transplantation while in remission, and the other six all relapsed within 10 months. All 31 patients died within 25 months after entering the study.

CONCLUSIONS

The regimen of high dose ara-C and mitoxantrone was found to be insufficiently effective to warrant further investigation.

Salvage therapy of refractory and relapsed acute leukemia with high dose mitoxantrone and high dose cytarabine

We have assessed the outcome of 66 refractory and relapsed acute leukemia patients treated with high dose mitoxantrone and cytarabine. Therapy consisted of a total dose of 40-60 mg/m2 mitoxantrone and 3 g/m2 of cytarabine daily on 5 consecutive days. A total of 28 patients were treated for primary resistant and 38 patients for early or late relapsed leukemia. A total of 35 patients achieved CR. Four patients died during the induction course. Toxicity was acceptable and comparable to other salvage regimens. The median disease-free and overall survivals were 4 and 6 months, respectively. Although this regimen is effective in achieving remission in refractory leukemia, its duration is short.

Amsacrine and continuous-infusion high-dose cytosine arabinoside as induction therapy for patients with newly-diagnosed acute myelogenous leukemia

The overall cure rate of adults with newly-diagnosed acute myelogenous leukemia (AML) treated with continuous infusion high-dose cytarabine (CIHDAC) is comparable to that with standard-dose ara-C plus anthracycline or amsacrine (AMSA). We tested whether the addition of AMSA to CIH-DAC improves the outcome of adults with untreated AML. 75 patients with untreated AML were treated with AMSA (75 mg/m2/day x 4) plus CIHDAC (1.5 g/m2/day x 4) for induction and, if in complete remission (CR), early and late intensification. Results were compared to those in 129 patients treated on a previous study with CIHDAC alone. The principal comparison in both groups was between those 117 patients (AMSA/CIHDAC n = 52, CIHDAC n = 65) who met the initial eligibility criteria for the AMSA/CIHDAC study (risk of early mortality < or = 1) and who were treated at a time when relatively few eligible patients were excluded (19% in the AMSA/CIHDAC group, 34% in the CIHDAC group). There was no difference between regimens in CR rate, remission duration, or survival in this cohort. When attention was turned to all 204 patients, outcome was superior with AMSA/CIHDAC very largely as a result of outcome in patients with APL. Aside from these patients, addition of amsacrine to CIHDAC did not appear to be productive.

An efficient new cannabinoid antiemetic in pediatric oncology

Delta-8-tetrahydrocannabinol (delta-8-THC), a cannabinoid with lower psychotropic potency than the main Cannabis constituent, delta-9-tetrahydrocannabinol (delta-9-THC), was administered (18 mg/m2 in edible oil, p.o.) to eight children, aged 3-13 years with various hematologic cancers, treated with different antineoplastic drugs for up to 8 months. The total number of treatments with delta-8-THC so far is 480. The THC treatment started two hours before each antineoplastic treatment and was continued every 6 hrs for 24 hours. Vomiting was completely prevented. The side effects observed were negligible.

Treatment of relapsed acute myeloid leukemia using GM-CSF before intensive chemotherapy

Ten patients with acute myeloblastic leukemia (AML) in first relapse were treated with high-dose cytosine-arabinoside (ara-C, 3 g/m2/12 hours x 4) and amsacrine (150 mg/m2/day x 5). In order to prime the cells, the patients were given rh-GM-CSF (3 micrograms/kg/d) for four days, the first infusion starting 48 hours before chemotherapy. Two patients died during the aplastic phase, seven patients achieved a second complete remission (CR2) and one patient remained leukemic. The median duration of aplasia was 17 days (14-21). These results were comparable to those obtained in our previous series of 27 patients treated for AML in first relapse with the same chemotherapy but without GM-CSF (66% CR2). After 48 hours of GM-CSF infusion, (before chemotherapy was started), seven patients had an increase in the white blood cell count with an increase in the absolute number of blast cells in five of these cases. Marrow blast cells percentages increased in 3 of the 8 patients analysed. Six of seven patients tested showed an increase in the percentage of cells in S-phase (studied by flow cytometry using the bromodeoxyuridine (BrdU/DNA) labelling technique and BrdU incorporation). GM-CSF used to prime leukemic cells may be safely administered but its clinical usefulness needs to be further evaluated.

Phase-II study of treatment of refractory acute leukemia with intermediate-dose cytosine arabinoside and amsacrine

Twenty-five consecutive leukemia patients (21 AML, 4 ALL) with either primary resistance (n = 22) or resistant relapse (n = 3) of all FAB subtypes were treated with 1 or 2 cycles of ID-ara C (1 g/m2 i.v. q 12 h, days 1-6) and AMSA (120 mg/m2 i.v., days 5-7). Patients reaching CR received 1 cycle of intensive consolidation using ara C 3 g/m2 i.v. q 12 h, days 1-4 and AMSA 120 mg/m2 i.v., day 5. Two patients received an allograft thereafter and are still alive and in CCR. CR was achieved in 12/25 patients (48%), ten after 1 cycle of induction and two after 2 cycles; 10/22 patients with primary resistant disease reached CR, and 2/3 with resistant relapse. Nine patients remained refractory (36%) and four died during hypoplasia (16%). Median DFS of the 12 responders was 2.9 months, median survival from time of CR 8.9 months. Median overall survival of responders and nonresponders was 6 months from time of resistance. Survival advantage of responding patients (n = 12) as compared with nonresponders (n = 13) was 10.7 vs. 3.2 months (p = 0.002). Toxicity of chemotherapy was acceptable: one patient experienced pulmonary edema due to ara C; two patients developed life-threatening systemic fungal infections, one of whom died while in CR.

AMSA combination chemotherapy in patients with acute myelogenous leukemia unsuitable for standard antileukemic treatment

Forty-eight patients with acute myelogenous leukemia (AML) not eligible for anthracycline or mitoxantrone treatment, mostly due to cardiac contraindications, were given aggressive therapy using m-amsacrine (AMSA) in combination with conventional or high-dose cytarabine for remission induction. Twenty-nine patients (60.4%) responded to treatment, and complete remission was attained in 19 (39.6%), partial remission in 4 (8.3%) and death in bone marrow aplasia without detectable blasts in 6 patients (12.5%). Median time to granulocyte recovery was 32 days, median duration of relapse-free survival 199 days. One patient experienced a serious cardiac adverse event; nausea and vomiting were observed in 73%, diarrhea in 44%, and hepatoxicity in 29% of patients. All potentially AMSA-related side effects were fully reversible, and a lethal complication did not occur. It is concluded that combination chemotherapy with AMSA and Ara-C is also effective and tolerable in leukemic patients in whom cardiotoxic drugs are contraindicated.

The combination of quercetin and cytosine arabinoside synergistically inhibits leukemic cell growth

It has been demonstrated that quercetin (3,3',4',5,7-pentahydroxyflavone) inhibits the growth of several cancer cell lines and that the antiproliferative activity of this substance is probably mediated through a binding interaction with type II estrogen binding sites (type II EBS). The effect of quercetin and cytosine arabinoside (Ara-C) alone or in combination, was tested on HL-60 cell growth. Quercetin significantly synergized the inhibitory activity of Ara-C on HL-60 cell growth while rutin, the 3-rhamnosylglucoside of quercetin, neither competed with [3H]estradiol for type II EBS nor was effective alone or in combination with Ara-C. Based on these results, we studied by a clonogenic assay the effect of quercetin and Ara-C alone and in combination on colony formation by human leukemic cells (CFU-L). In all cases both drugs exhibited a dose-related inhibition of CFU-L in a range of concentrations between 10 nM and 10 microM and 0.01 nM and 10 microM for quercetin and Ara-C, respectively. The combination of the two drugs resulted in a synergistic inhibitory activity on CFU-L. Considering that plasma concentrations of quercetin effective in vitro were obtained in vivo without any apparent side effects, we conclude that this report represents further experimental evidence that quercetin could be used in the treatment of acute leukemias.

Amsacrine is safe and effective therapy for patients with myocardial dysfunction and acute leukemia

The role of amsacrine in inducing remission in patients with cardiac disease and acute leukemia was evaluated. There were 17 patients with acute myelogenous leukemia (AML), six with acute lymphocytic leukemia (ALL), and one with biphenotypic leukemia. In this series of 24 patients whose disease had relapsed and who had reduced left ventricular ejection fraction, nine had a complete remission, seven with AML and two with ALL. In addition, four of six with newly diagnosed acute leukemia and reduced left ventricular ejection fraction also responded. Among nine patients who underwent endomyocardial biopsy, none had morphologic changes of sufficient degree to account for drug-induced heart failure. Patients with preexisting arrhythmias received amsacrine without incident if their serum potassium level was higher than 4.0 mEq/l at the time of drug administration. Amsacrine is safe and effective therapy for patients with acute leukemia and cardiac disease.

Five-day 4'-(9-acridinylamino)methanesulphon-m-anisidide and intermediate-dose cytosine arabinoside in high-risk relapsing or refractory acute myeloid leukemia

Twenty-two patients with acute myeloid leukemia (AML), having a median age of 48.3 years (range 26-70; 10 male, 12 female), were treated with 4'-(9-acridinylamino) methanesulphon-m-anisidide (m-AMSA) 100 mg/m2 and cytosine arabinoside (AraC) 2 x 1000 mg/m2i.v. on days 1-5. There were 2M1,8 M2, 9 M4, 2M4 Eo, and 1 M5a. Of these, 12 achieved a complete remission, 3 a partial remission and 6 did not respond. The median remission duration was 9.0 months and the median overall survival 8.1 months. Side-effects of induction consisted mainly of haematological toxicity and infections with a median duration of WHO-grade-4 granulopenia and thrombopenia of 20 and 28 days respectively. Organ toxicity was mild with mucositis and cutaneous and liver toxicity being experienced by only a few patients. There was one treatment-related death. Five-day m-AMSA and intermediate-dose AraC is an easy-to-handle condensed treatment schedule with tolerable toxicity. Its effectiveness in relapsed and refractory AML is comparable to combinations of high-dose AraC with m-AMSA, anthracyclines or etoposide.

Successful reinduction therapy with amsacrine and cyclocytidine in acute nonlymphoblastic leukemia in children. A report from the Childrens Cancer Study Group

Amsacrine (AMSA) and cyclocytidine were studied as retrieval therapy in 122 pediatric patients with acute nonlymphoblastic leukemia (ANLL). Patients either failed to achieve sustained initial remissions or were in relapse. Induction therapy consisted of intravenous (IV) AMSA (75 mg/m2) from days 1 to 5 and subcutaneous cyclocytidine (600 mg/m2) from days 1 to 7. Maintenance therapy consisted of IV etoposide (VP-16) (100 mg/m2) for 5 days and IV AMSA (100 mg/m2) on day 1. Of 122 patients, 109 were evaluable. There were 13 early deaths. Ninety-six patients received adequate therapy defined as completion of two courses of therapy. Of these 96 patients, 52 achieved complete remission. Fifteen of 33 patients who failed initial induction achieved complete remission. Eighteen of 39 patients who were resistant to anthracyclines had complete responses. There was no direct evidence of AMSA-induced cardiotoxicity. Remission duration was 28 days to 3 or more years (median, 98 days). AMSA and cyclocytidine were effective retrieval therapy for patients who were in relapse or unresponsive to frontline therapy. Duration of remission was short (median, 98 days).

High-dose cytosine arabinoside and L-asparaginase therapy for poor-risk adult acute nonlymphocytic leukemia. A retrospective study

The effectiveness and toxicities of high-dose cytosine arabinoside with L-asparaginase (HiDAC-ASNase) were evaluated in 41 patients with "poor risk" acute nonlymphocytic leukemia (ANLL). Twenty-four patients had either refractory or relapsed primary ANLL, and 17 had ANLL secondary to prior cytotoxic chemotherapy or an underlying hematologic disorder. The overall complete remission (CR) rate was 37%. The CR rates for primary and secondary ANLL were almost identical. Furthermore, advanced age alone did not adversely influence the CR rate. The median CR duration was 302 days with no differences between primary and secondary ANLL. The induction death rate was 24%. Predictors for induction deaths included poor initial performance status, fever at the time of presentation, low cholesterol and/or albumin, and an initial bone marrow aspirate with greater than 50% blasts. These data indicate that HiDAC-ASNase is a moderately effective regimen for patients with poor prognosis ANLL including secondary ANLL.

Intermediate-dose cytosine arabinoside and amsacrine. An effective regimen with low toxicity in refractory acute nonlymphocytic leukemia

Results of remission induction therapy in refractory acute nonlymphocytic leukemia (ANLL) has been improved since the introduction of high-dose cytosine arabinoside. However, the toxicity of these regimens attributes to an early death rate of about 20% to 30%. The authors treated 37 poor-risk patients with ANLL with intermediate-dose cytosine arabinoside and amsacrine for remission induction. One consolidation course and no maintenance therapy was given. Eleven of 19 patients with a first relapse entered complete remission (58%); ten of 15 patients in this group older than 50 years were complete responders (67%). Median duration of second remission was 8.2 months (range, 2-14). Three of 13 patients with primarily resistant disease had a complete remission (23%), but there was no response in five patients with a myeloid blastic phase of chronic myelogenous leukemia. Side effects of this remission induction regimen were mild; no cardiac, pulmonary, or central nervous system toxicity was observed. Five patients (14%) died during the remission induction phase, three from complications during aplasia and two from refractory leukemia.

Amsacrine, cytarabine and etoposide in the treatment of bad prognosis acute myeloid leukemia

Thirty-seven patients (median age 50 yr, range 17-82) with acute myeloid leukemia (AML) received intensive induction treatment with amsacrine, cytarabine and etoposide in combination. Nine of the patients were refractory to previous induction therapy, 15 relapsed during or after treatment with daunorubicin and cytarabine, 13 had AML after previous hematologic disorders. Eleven of the patients with AML after previous hematologic disorders had been treated with cytotoxic drugs. Toxicity was substantial, but complete remission (CR) was achieved in 33% of patients with refractory AML, 47% of patients with AML in relapse, 54% of patients with AML after antecedent blood disorder. CR duration was 15 weeks (median). Patients with AML of FAB types M4 and M5 entered remission more often (70%) than patients with other AML types (37%).

Acute myelogenous leukaemia in children

Acute myelogenous leukaemia in childhood is considerably more resistant to chemotherapy than the acute lymphocytic leukaemias. Recently, more aggressive therapy has improved the outlook for children with this difficult form of leukaemia. Long-term disease-free survival of children achieving remission has been reported to be more than 40% in some studies. This paper reviews both the present concept of leukaemogenesis as well as some of the more recent therapeutic studies on childhood AML.

Treatment of the blastic phase of chronic myelogenous leukemia with mitoxantrone and high-dose cytosine arabinoside

Twenty-seven patients in the blastic phase of chronic myelogenous leukemia received combination chemotherapy with mitoxantrone 5 mg/m2 intravenously daily for 5 days, and cytosine arabinoside 3 g/m2 intravenously over 2 hours every 12 hours for six doses. The patients' median age was 42 years (range, 19-61 years), and 26 of them had Philadelphia chromosome-positive disease. Overall, seven patients (26%) achieved complete remission, and one (4%) had a partial remission for an overall response rate of 30%. Eight patients died during remission induction, and 11 had resistant disease. The median survival was 14 weeks for the total population, and 24 weeks for patients achieving a complete remission. The nonmyelosuppressive toxicity of the combination was acceptable; serious neurologic and pulmonary toxicities were uncommon. Significant marrow hypoplasia was observed resulting in a high incidence of febrile episodes (85% of patients). The combination of mitoxantrone and high-dose cytosine arabinoside did not significantly improve overall prognosis. Since chemotherapy continues to produce disappointing results, other innovative approaches need to be explored.