Evaluation of intensive postremission chemotherapy for adults with acute nonlymphocytic leukemia using high-dose cytosine arabinoside with L-asparaginase and amsacrine with etoposide

Biochemical characterization of a novel L-Asparaginase with low glutaminase activity from Rhizomucor miehei and its application in food safety and leukemia treatment

A novel fungal gene encoding the Rhizomucor miehei l-asparaginase (RmAsnase) was cloned and expressed in Escherichia coli. Its deduced amino acid sequence shared only 57% identity with the amino acid sequences of other reported l-asparaginases. The purified l-asparaginase homodimer had a molecular mass of 133.7 kDa, a high specific activity of 1,985 U/mg, and very low glutaminase activity. RmAsnase was optimally active at pH 7.0 and 45°C and was stable at this temperature for 30 min. The final level of acrylamide in biscuits and bread was decreased by about 81.6% and 94.2%, respectively, upon treatment with 10 U RmAsnase per mg flour. Moreover, this l-asparaginase was found to potentiate a lectin's induction of leukemic K562 cell apoptosis, allowing lowering of the drug dosage and shortening of the incubation time. Overall, our findings suggest that RmAsnase possesses a remarkable potential for the food industry and in chemotherapeutics for leukemia.

Acute myeloid leukemia with concurrent myeloid sarcoma treated with autologous bone marrow transplantation: two illustrative cases and a literature review

Myeloid sarcoma (MS) is an invasive extramedullary solid tumor composed of immature cells of the myeloid series. It complicates the clinical course of a minority of patients with acute myeloid leukemia (AML). Traditionally its presence has been regarded as an indicator of aggressive disease. Currently, the optimal treatment of AML with concurrent MS remains to be determined. We report two cases of autologous bone marrow transplantation (auto-BMT) for AML with concurrent MS followed by a review of the literature.

Duration of second complete remission compared with first complete remission in patients with acute myeloid leukemia. Eastern Cooperative Oncology Group

The prognosis for patients with acute myeloid leukemia in first relapse is generally poor. The ability to induce a second complete remission (CR) with the same chemotherapy used in initial induction therapy is limited. Remission inversion rate, defined as achieving a longer second CR than the first CR in response to standard chemotherapy for relapse, is important in assessing studies of novel chemotherapy or immunologic treatment strategies for patients with relapsed disease. One hundred and twenty-four patients entered on two Eastern Cooperative Oncology Group (ECOG) studies for patients with relapsed AML were analyzed to determine the remission inversion rate. Twenty-two of the 124 patients (18%; 95% confidence interval 12-26%) experienced a longer second CR duration than the first CR duration by at least 2 months. Inversion of CR duration is thus not a rare event. The inversion frequency reported here establishes a baseline upon which future studies in relapsed disease need to be defined.

High-dose chemotherapy in adult acute myeloid leukemia: rationale and results

Preclinical studies and retrospective evaluations of clinical trials of a number of cytotoxic drugs have provided a rationale for the use of high doses of chemotherapy in adults with acute myeloid leukemia (AML). To maximize cure and remission rates at an acceptable cost in toxicity, many schedules and combinations of dose-intensive chemotherapy have been tested in recent years in patients with de novo disease, cytosine arabinoside (Ara-C) being the most extensively evaluated drug. In this article we review the principal results of both randomized and non-controlled studies. Our analysis indicates that high-dose Ara-C (HIDAC) used during induction results is no substantial benefit relative to conventional doses of drug. On the other hand, consolidation with HIDAC is a major advance in the treatment of this disease. In fact, in individuals less than 60 years of age and a favorable or intermediate-risk karyotype, HIDAC-based regimens have resulted in survival estimates comparable to those of autologous or allogeneic bone marrow transplantation. Yet, the role of HIDAC is irrelevant in younger individuals with an unfavorable cytogenetic pattern and detrimental in patients greater than 60 years of age. Since recently new cytotoxic agents have expanded the armamentarium of antileukemic drugs, well conducted randomized trials of dose intensive chemotherapy still need to be performed to optimize schedules and combinations of drugs in patients with AML.

High-dose cytosine arabinoside and daunorubicin postremission therapy in adults with de novo acute myeloid leukemia. Long-term follow-up of a prospective multicenter trial

A total of 149 consecutive de novo AML patients aged 50 years or less (median age = 37 years) were enrolled in this prospective multicenter trial initiated in May 1985. All patients received the same induction and early consolidation therapy with daunorubicin (DNR), cytosine arabinoside (Ara-C), and etoposide (DAV). High-dose Ara-C/DNR therapy included Ara-C at 3 g/m2, in 12 doses (HD-Ara-C/DNR I) and eight doses (HD-Ara-C/DNR II), followed by DNR 30 mg/m2 for 3 days. A complete remission (CR) was achieved in 104 (70%) patients; 61 complete responders received at least one cycle with HD-Ara-C/DNR. If those patients who were transplanted in first CR (n = 26), were not considered, the median relapse-free-survival (MRFS) of the remaining 78 patients was 15 months, with a probability of relapse-free survival (RFS) at 116 months of 30% (95% CI, 20-40%) after a median follow-up of 95 months. The MRFS of the HD-Ara-C/DNR consolidated patients was 25 months, with a probability of RFS at 116 months of 37% (95% CI, 24-50%). If all patients who were transplanted (n = 44) were not considered, the median survival time (MST) was 18 months with a probability of being alive at 118 months of 24% (95% CI, 16-33%). MST of the HD-Ara-C/DNR consolidated patients was 58 months with a survival probability of 46% (95% CI, 31-60%) at 118 months. Prognostic factor analysis did not reveal any significant influence of age, sex, FAB subtype, white blood cell count, hemoglobin level, thrombocyte count, LDH, or response to the first induction course on RFS of the HD-Ara-C/DNR consolidated patients. In summary, HD-Ara-C/DNR consolidation can improve the long-term outcome of a subgroup of de novo AML patients. Further improvement of the outcome seems to depend on the identification of patients with an inferior outcome under that strategy who might benefit from alternative treatment strategies.

1-Beta-arabinofuranosylcytosine in therapy of leukemia: preclinical and clinical overview

Although the mechanisms of therapeutic efficacy of cytosine arabinoside (Ara-C) are multifactorial, the pharmacodynamic basis for its cytotoxicity and therapeutic efficacy lies in its intracellular metabolism and the retention of the active metabolite, Ara-C triphosphate (Ara-CTP), which is a competitive inhibitor of DNA polymerase. Additional determinants of tumor cell sensitivity include Ara-CMP incorporation into cellular DNA, the size of the competing normal metabolite, deoxycytidine/5'-triphosphate pool, and the heterogeneity in growth kinetics of tumor cells, S-phase vs cells in other phases of the cell cycle. With high-dose Ara-C, substantial amounts of Ara-CTP are formed in phases of the cell cycle. The presence of high intracellular concentration with prolonged retention of Ara-CTP could lead to the inhibition of cell growth of the cells entering S-phase as a consequence of inhibition of DNA-polymerase and/or incorporation into cellular DNA, resulting in a chain termination. Pharmacokinetically, Ara-C is rapidly eliminated from plasma. In mice, pharmacokinetic parameters of Ara-C are not sufficient predictors for the observed differences in their in vivo antitumor activity. Although these mice were bearing different tumor types (L1210 Ara-C sensitive or P-388 relatively more resistant), the observed differences in tumor response were achieved under identical plasma Ara-C concentrations and area under the concentration time curve. The observed antitumor activity in L1210 cells is primarily associated with higher Ara-CTP pools and retention (T1/2 > 4 hr) in tumor cells as compared with normal bone marrow cells. In the least responsive tumor (P-388), although Ara-CTP pools were sufficiently high, retention of the drug in tumor cells and in normal cells is poor with a T1/2 < 2 hr. Thus, unlike mice bearing leukemia L1210 cells, alteration of the mode and dose of administration of Ara-C in mice bearing P-388 could only result in increased host toxicity with no therapeutic gain. Similarly in patients with acute nonlymphocyte leukemia (ANLL), there is no significant correlation between plasma Ara-C concentration and the intracellular concentrations or retentions of Ara-CTP. In some patients the highest Ara-CTP pools in leukemic myeloblast cells are achieved at a lower level of plasma Ara-C and decrease further with the increase of plasma Ara-C. Thus, in the in vivo model system and in ANLL patients with no prior chemotherapy, Ara-CTP retention is a critical factor associated with response to this agent, in particular its direct association with duration of complete response.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute myeloid leukemia in the elderly: biological features and search for adequate treatment

AML in elderly patients is a heterogeneous disease which is characterized by a number of unfavorable features such as development, cytogenetics, blast cell differentiation, and poor treatment response. Specifically, the association between a higher incidence of unfavorable cytogenetic abnormalities in elderly patients and poor prognosis has been well documented. Low treatment response may be due to the specific biology of AML in this patient group, but also to host-specific factors such as higher treatment-related morbidity and mortality. Treatment tolerance cannot be judged on grounds of chronological age alone; risk factor analysis with regard to performance status, organ function, and underlying systemic disease need to be considered as well. For effective induction treatment in elderly patients, instant and intensive chemotherapy appears to be necessary, while delayed treatment or administration of supportive care alone provide unsatisfactory results. Standard-dose ara-C/anthracycline-containing regimens are the treatment of choice in patients with good performance status. However, patients with a WHO grading of greater than 3 might rather benefit from reduced regimens such as low-dose ara-C. At present, greatest improvement of AML treatment in elderly patients can be expected from an improvement of supportive care.

Cytosine arabinoside in the treatment of acute myeloid leukemia: the role and place of high-dose regimens

Cytosine arabinoside (AraC) is one of the most active drugs in the treatment of acute leukemias and is widely applied at all phases of therapy. In spite of extensive clinical and experimental investigations, its intracellular metabolism and especially its mechanism of action are still not fully elucidated. Controversy also continues about the most appropriate way and dose of administration; which differs by more than 100 fold in clinical studies ranging from low-dose, over standard and intermediate dose regimens, to high-dose protocols. The present review is focused on the role and place of high-dose AraC treatment in acute myeloid leukemia (AML). Based on available clinical and experimental data, the following conclusions can be drawn: Not considering possible but not yet demonstrated beneficial long-term effects, the incorporation of high-dose AraC into induction therapy has not resulted in an improvement of overall remission rate, with the possible exception of patients with slow initial cytoreduction after a first course of conventional treatment. Promising results, however, emerge from high-dose AraC-based consolidation protocols, which need confirmation in prospectively randomized comparative trials. In relapsed and refractory AML, higher than conventional doses undoubtedly enhance the efficacy of AraC salvage therapy. The question of whether the antileukemic activity of intermediate-dose regimens with 500-1,000 mg/m2 AraC is equivalent to that of high-dose protocols applying 2,000-3,000 mg/m2 AraC, however, remains open but may soon be answered by ongoing controlled clinical and pharmacologic investigations.

Etoposide in leukemia

Etoposide (VP16-213, NSC 141540) induces a complete response (CR) in 15% to 25% of previously treated patients with acute nonlymphocytic leukemia (ANLL) when used as a single agent. Etoposide has been used successfully in combination with cytarabine, daunorubicin, and amsacrine for salvage and consolidation therapies. Previously untreated ANLL patients 15 to 70 years of age were randomly assigned to cytarabine (100 mg/m2) on days 1 to 7 plus daunorubicin (50 mg/m2) on days 1 to 3 (7-3) or to the same drugs plus etoposide (75 mg/m2) on days 1 to 7 (7-3-7). Patients achieving a CR received two consolidation courses (5-2, attenuated 7-3 or 5-2-5). Among 264 eligible patients, there was a 56% CR rate with 7-3 therapy and a 59% CR rate with 7-3-7 therapy. Remission duration was significantly improved with 7-3-7 (median, 12 months with 7-3 and 18 months with 7-3-7; P = 0.01), but survival was not. Subset analysis in patients younger than 55 years of age revealed prolonged remission (median, 12 months with 7-3 and 27 months with 7-3-7; P = 0.01) and survival (median, 9 months with 7-3 and 17 months with 7-3-7; P = 0.04) with the 7-3-7 regimen. Hematologic toxicity was similar for both regimens during induction, but significantly more severe for 7-3-7 during consolidation therapy. Etoposide is active in ANLL and prolongs remission when used in induction therapy.

Etoposide and teniposide in the treatment of acute leukemia

Etoposide and teniposide are semi-synthetic glucoside derivatives of podophyllotoxin with a documented anti-tumour activity in various types of malignant diseases. It was an early observation that these epiphodophyllotoxins were efficacious in hematological malignancies such as lymphomas and leukemias. In this report the clinical evidence supporting the activity of etoposide and teniposide in acute lymphoblastic (ALL) and non-lymphoblastic leukemia (ANLL) is reviewed. Unlike podophyllotoxin, etoposide and teniposide do not appear to affect microtubular function nor arrest cells in mitosis. These epiphodophyllotoxins, like other DNA intercalating agents, have topoisomerase II as their target. Most studies with etoposide have been performed in ANLL and with teniposide in ALL. This choice seems to be rather arbitrary and is better explained by traditional reasons than actual study results. The data in acute leukemias are partly flawed by the absence of certain prospective comparative trials. However, the current information on etoposide clearly shows that this agent has substantial activity in ANLL and may well be incorporated into front-line regimens and the same is true for teniposide in the treatment of ALL. Nevertheless, based on available literature, there are no convincing data to the author's mind to support that one of these agents is superior to the other in the treatment of acute leukemias.

Combination of pipemidic acid, colistin sodium methanesulfonate and nystatin may be less effective than nystatin alone for prevention of infection during chemotherapy-induced granulocytopenia in acute leukemia

Pipemidic acid (PPA) and colistin sodium methanesulfonate (CLM) may selectively suppress aerobic gram-negative bacilli. Twenty-nine patients with acute leukemia were randomized after each course of consolidation chemotherapy to receive a single agent of nystatin (NYS) (34 courses) versus a combination of NYS, PPA and CLM (36 courses). The duration of fever over 39 degrees C was longer with the three drug combination (4.6 +/- 5.1 days) than with NYS alone (1.8 +/- 1.8 days) (P less than 0.01). Four cases of pneumonia occurred and four patients including one having pneumonia died of infection with the three drug combination, while no pneumonia or death occurred with NYS alone (P = 0.06 and P = 0.06, respectively). The combination of NYS, PPA and CLM may be less effective than NYS alone for the prevention of infection in acute leukemia patients with chemotherapy-associated granulocytopenia.

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.

Aggressive chemotherapy in adult primary myelodysplastic syndromes. A report on 29 cases

Twenty-nine adult patients with primary myelodysplastic syndromes (MDS) and an excess of marrow blasts were treated by aggressive chemotherapy while still in MDS phase (20 cases) or after progression to ANLL (9 cases). Median age was 47.5 (range 18-68). Twenty-eight patients received a combination of Rubidazone and Ara C and 1 received High dose Ara C. Fourteen patients (48%) achieved complete remission (CR), 5 (17%) were treatment failures (F) and 10 (35%) died during therapy induced aplasia (DA). Median disease free survival was 8.5 months. Median survival of the whole population was 6 months from the onset of treatment, and 17 months in patients achieving CR. These results were significantly less favorable than those obtained at our institution in de novo ANLL with the same chemotherapy regimens. No statistically significant prognostic factors of treatment outcome emerged but patients with normal cytogenetic findings seemed to have both a higher CR rate and longer remissions than patients with abnormal karyotypes. Patients under 50 did not have higher CR rates than older patients, although they had longer remissions (with 3 out of 6 CRs exceeding 2 years). Finally, treatment outcome and survival were identical in patients treated in the MDS phase and in those treated after progression to ANLL. Combination chemotherapy is a highly toxic approach in MDS and essentially seems to benefit younger patients with a normal karyotype, in whom some long remissions can be obtained.