High antileukemic activity of sequential high dose cytosine arabinoside and mitoxantrone in patients with refractory acute leukemias

Randomized trial comparing standard vs sequential high-dose chemotherapy for inducing early CR in adult AML

Here we evaluated whether sequential high-dose chemotherapy (sHD) increased the early complete remission (CR) rate in acute myelogenous leukemia (AML) compared with standard-intensity idarubicin-cytarabine-etoposide (ICE) chemotherapy. This study enrolled 574 patients (age, 16-73 years; median, 52 years) who were randomly assigned to ICE (n = 286 evaluable) or sHD (2 weekly 3-day blocks with cytarabine 2 g/m² twice a day for 2 days plus idarubicin; n = 286 evaluable). Responsive patients were risk-stratified for a second randomization. Standard-risk patients received autograft or repetitive blood stem cell-supported high-dose courses. High-risk patients (and standard-risk patients not mobilizing stem cells) underwent allotransplantation. CR rates after 2 induction courses were comparable between ICE (80.8%) and sHD (83.6%; P = .38). sHD yielded a higher single-induction CR rate (69.2% vs 81.5%; P = .0007) with lower resistance risk (P < .0001), comparable mortality (P = .39), and improved 5-year overall survival (39% vs 49%; P = .045) and relapse-free survival (36% vs 48%; P = .028), despite greater hematotoxicity delaying or reducing consolidation blocks. sHD improved the early CR rate in high-risk AML (odds ratio, 0.48; 95% confidence interval [CI], 0.31-0.74; P = .0008) and in patients aged 60 years and less with de novo AML (odds ratio, 0.46; 95% CI, 0.27-0.78; P = .003), and also improved overall/relapse-free survival in the latter group (hazard ratio, 0.70; 95% CI, 0.52-0.94; P = .01), in standard-risk AML, and postallograft (hazard ratio, 0.61; 95% CI, 0.39-0.96; P = .03). sHD was feasible, effectively achieved rapid CR, and improved outcomes in AML subsets. This study is registered at www.clinicaltrials.gov as #NCT00495287.

Model-Based Optimal AML Consolidation Treatment

OBJECTIVE

Neutropenia is an adverse event commonly arising during intensive chemotherapy of acute myeloid leukemia (AML). It is often associated with infectious complications. Mathematical modeling, simulation, and optimization of the treatment process would be a valuable tool to support clinical decision making, potentially resulting in less severe side effects and deeper remissions. However, until now, there has been no validated mathematical model available to simulate the effect of chemotherapy treatment on white blood cell (WBC) counts and leukemic cells simultaneously.

METHODS

We developed a population pharmacokinetic/pharmacodynamic (PK/PD) model combining a myelosuppression model considering endogenous granulocyte-colony stimulating factor (G-CSF), a PK model for cytarabine (Ara-C), a subcutaneous absorption model for exogenous G-CSF, and a two-compartment model for leukemic blasts. This model was fitted to data of 44 AML patients during consolidation therapy with a novel Ara-C plus G-CSF schedule from a phase II controlled clinical trial. Additionally, we were able to optimize treatment schedules with respect to disease progression, WBC nadirs, and the amount of Ara-C and G-CSF.

RESULTS

The developed PK/PD model provided good prediction accuracies and an interpretation of the interaction between WBCs, G-CSF, and blasts. For 14 patients (those with available bone marrow blast counts), we achieved a median 4.2-fold higher WBC count at nadir, which is the most critical time during consolidation therapy. The simulation results showed that relative bone marrow blast counts remained below the clinically important threshold of 5%, with a median of 60% reduction in Ara-C.

CONCLUSION

These in silico findings demonstrate the benefits of optimized treatment schedules for AML patients.

SIGNIFICANCE

Until 2017, no new drug had been approved for the treatment of AML, fostering the optimal use of currently available drugs.

Mathematical models for cytarabine-derived myelosuppression in acute myeloid leukaemia

We investigate the personalisation and prediction accuracy of mathematical models for white blood cell (WBC) count dynamics during consolidation treatment using intermediate or high-dose cytarabine (Ara-C) in acute myeloid leukaemia (AML). Ara-C is the clinically most relevant cytotoxic agent for AML treatment. We extend a mathematical model of myelosuppression and a pharmacokinetic model of Ara-C with different hypotheses of Ara-C's pharmacodynamic effects. We cross-validate the 12 model variations using dense WBC count measurements from 23 AML patients. Surprisingly, the prediction accuracy remains satisfactory in each of the models despite different modelling hypotheses. Therefore, we compare average clinical and calculated WBC recovery times for different Ara-C schedules as a successful methodology for model discrimination. As a result, a new hypothesis of a secondary pharmacodynamic effect on the proliferation rate seems plausible. Furthermore, we demonstrate the impact of treatment timing on subsequent nadir values based on personalised predictions as a possibility for influencing/controlling myelosuppression.

Minimal residual disease as biomarker for optimal biologic dosing of ARA-C in patients with acute myeloid leukemia

We assessed by flow cytometry minimal residual disease (MRD) in patients with acute myeloid leukemia (AML) given standard-dose (SDAC) and high-dose ARA-C (HDAC) regimens. Of 163 patients enrolled, 130 (median age, 45 years; range, 18-59 years) qualified for analysis, all achieving complete remission after treatment with SDAC (n = 78) or HDAC (n = 52) plus etoposide and daunorubicin. Consolidation consisted of intermediate-dose ARA-C and daunorubicin. MRD negativity was significantly more frequent in the SDAC vs. HDAC arm after both induction (37% vs. 15%, P = 0.007) and consolidation (44% vs. 18%, P = 0.002). Respective median residual leukemic cell counts with SDAC and HDAC use were 1.5 × 10(-3) and 4 × 10(-3) (P = 0.033) after induction and 5.7 × 10(-4) and 2.9 × 10(-3) (P = 0.008) after consolidation. Based on ARA-C schedule and post-consolidation MRD status, the four patient groups (SDAC-MRD(-) , HDAC-MRD(-) , SDAC-MRD(+) , and HDAC-MRD(+) ) displayed 5-year overall survival rates of 60%, 33%, 24%, and 42% (P = 0.007), respectively, with 24%, 35%, 74%, and 48% (P < 0.0001) respective cumulative incidence of relapse estimates. MRD may serve as a biomarker for optimal biologic dosing of ARA-C, and SDAC regimen appears to yield more frequent MRD negativity.

A phase Ib GOELAMS study of the mTOR inhibitor RAD001 in association with chemotherapy for AML patients in first relapse

The mTORC1 signaling pathway is constitutively activated in almost all acute myelogenous leukemia (AML) patients. We conducted a phase Ib trial combining RAD001 (everolimus), an allosteric inhibitor of mTORC1, and conventional chemotherapy, in AML patients under 65 years of age at first relapse (clinical trial NCT 01074086). Increasing doses of RAD001 from 10-70 mg were administrated orally on days 1 and 7 (d1 and d7) of a 3+7 daunorubicin+cytarabine conventional induction chemotherapy regimen. Twenty-eight patients were enrolled in this trial. The treatment was well tolerated with <10% toxicity, mainly involving the gastrointestinal tract and lungs. In this phase Ib trial, the RAD001 maximum tolerated dose was not reached at 70 mg. Sixty-eight percent of patients achieved CR, of which 14 received a double induction. Eight subsequently were intensified with allogeneic-stem cell transplant. Strong plasma inhibition of P-p70S6K was observed after RAD001 administration, still detectable at d7 (d7)at the 70 mg dosage. CR rates in patients with RAD001 areas under or above the curve median were 53% versus 85%. A 70 mg dose of RAD001 at d1 and d7 of an induction chemotherapy regimen for AML has acceptable toxicity and may improve treatment.

Chemotherapy for initial induction failures in childhood acute lymphoblastic leukemia: a Children's Oncology Group Study (POG 8764)

Children with acute lymphocytic leukemia who fail to enter remission have a poor prognosis. In a previous study, 9 of 14 children with induction failure entered remission after teniposide (VM26) plus cytosine arabinoside (Ara-C). We attempted to confirm these results. Twenty children received teniposide (200 mg/m/day IV) for 3 days and cytosine arabinoside (100 mg/m/day continuous IV infusion) for 7 days. There were 3 complete and 3 partial responses. Two additional patients achieved a complete response after a second, shorter course of the same agents. Although VM26 plus Ara-C is an active combination for treatment of acute lymphocytic leukemia induction failure, it does not appear as effective as in the initial report. Better treatments for this problem are needed.

Docosahexaenoic acid: a natural powerful adjuvant that improves efficacy for anticancer treatment with no adverse effects

Epidemiological studies have linked fish oil consumption to a decreased incidence of cancer. The anticancer effects of fish oil are mostly attributed to its content of omega-3 fatty acids: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). However, DHA, because of its unique effect of altering membrane composition, is often regarded as the major omega-3 fatty acid involved in anticancer activity. Although use of DHA as an anticancer drug to prevent or treat human cancer in clinical settings has not yet been well established, recent studies suggest that DHA can be very effective as an adjuvant with other anticancer agents. In this article, we present studies that show the role of DHA in improving anticancer drug efficacy. Several in vitro and animal studies suggest that combining DHA with other anticancer agents often improves efficacy of anticancer drugs and also reduces therapy-associated side effects. Incorporation of DHA in cellular membranes improves drug uptake, whereas increased lipid peroxidation is another mechanism for DHA-mediated enhanced efficacy of anticancer drugs. In addition, several intracellular targets including cyclooxygenase-2, nuclear factor kappa B, peroxisome proliferator-activated receptor gamma, mitogen-activated protein kinase, AKT, and BCL-2/BAX are found to play an important role in DHA-mediated additive or synergistic interaction with anticancer drugs. The data suggest that DHA is a safe, natural compound that can greatly improve the anticancer properties of anticancer drugs. Use of DHA with anticancer treatments provides an avenue to therapeutic improvement that involves less risk or side effects for patients and reduced regulatory burden for implementation.

Phase 1 and pharmacokinetic study of bolus-infusion flavopiridol followed by cytosine arabinoside and mitoxantrone for acute leukemias

Flavopiridol is a protein bound, cytotoxic, cyclin-dependent kinase inhibitor. Flavopiridol given by 1-hour bolus at 50 mg/m(2) daily 3 times followed by cytosine arabinoside and mitoxantrone (FLAM) is active in adults with poor-risk acute leukemias. A pharmacologically derived "hybrid" schedule (30-minute bolus followed by 4-hour infusion) of flavopiridol was more effective than bolus administration in refractory chronic lymphocytic leukemia. Our phase 1 trial "hybrid FLAM" in 55 adults with relapsed/refractory acute leukemias began at a total flavopiridol dose of 50 mg/m(2) per day 3 times (20-mg/m(2) bolus, 30-mg/m(2) infusion). Dose-limiting toxicity occurred at level 6 (30-mg/m(2) bolus, 70-mg/m(2) infusion) with tumor lysis, hyperbilirubinemia, and mucositis. Death occurred in 5 patients (9%). Complete remission occurred in 22 (40%) across all doses. Overall and disease-free survivals for complete remission patients are more than 60% at more than 2 years. Pharmacokinetics demonstrated a dose-response for total and unbound plasma flavopiridol unrelated to total protein, albumin, peripheral blast count, or toxicity. Pharmacodynamically, flavopiridol inhibited mRNAs of multiple cell cycle regulators, but with uniform increases in bcl-2. "Hybrid FLAM" is active in relapsed/refractory acute leukemias, with a recommended "hybrid" dose of bolus 30 mg/m(2) followed by infusion of 60 mg/m(2) daily for 3 days. This clinical trial is registered at www.clinicaltrials.gov as #NCT00470197.

Dose-dense induction with sequential high-dose cytarabine and mitoxantone (S-HAM) and pegfilgrastim results in a high efficacy and a short duration of critical neutropenia in de novo acute myeloid leukemia: a pilot study of the AMLCG

Dose density during early induction has been demonstrated to be one of the prime determinants for treatment efficacy in acute myeloid leukemia (AML). The German AML Cooperative Group has therefore piloted a dose-dense induction regimen sequential high-dose AraC and mitoxantrone followed by pegfilgrastim (S-HAM) in which 2 induction cycles are applied over 11 to 12 days instead of 25 to 29 days as used in conventional double induction, thereby increasing dose density 2-fold. Of 172 de novo AML patients (excluding acute promyelocytic leukemia), 61% reached a complete remission, 22% a complete remission with incomplete peripheral recovery, 7% had persistent leukemia, 10% died (early death) resulting in an overall response rate of 83%. Kaplan-Meier estimated survival at 2 years was 61% for the whole group (patients with unfavorable karyotypes, 38%; patients with favorable karyotypes, 69%; patients with intermediate karyotypes, 75%) after S-HAM treatment. Importantly, the compression of the 2 induction cycles into the first 11 to 12 days of treatment was beneficial for normal hematopoiesis as demonstrated by a significantly shortened duration of critical neutropenia of 31 days compared with 46 days after conventionally timed double induction. (European Leukemia Trial Registry LN_AMLINT_2004_230.)

Absolute lymphocyte count is a novel prognostic indicator in ALL and AML: implications for risk stratification and future studies

BACKGROUND

Leukemia is the leading cause of disease-related death in children, despite significant improvement in survival and modern risk stratification. The prognostic significance of absolute lymphocyte counts (ALC) was evaluated in young patients with acute myeloblastic leukemia (AML) and acute lymphoblastic leukemia (ALL).

METHODS

In all, 171 consecutive de novo cases of AML and ALL, age <or=21 years, were analyzed. Age, initial white blood cell count, cytogenetics, and bone marrow response were compared with lymphocyte, neutrophil, and platelet counts at weekly intervals during induction chemotherapy.

RESULTS

ALC is a significant independent predictor of relapse and survival. For example, in patients with AML an ALC on Day 28 of induction (ALC-28) <350 cells/microL predicts very poor survival, with a 5-year relapse-free survival (RFS) of only 10% (hazard ratio [HR] 3.7, P= .003). In contrast, an ALC-15 >350 cells/microL carries an excellent prognosis, with a 5-year overall survival (OS) of 85% (HR 0.2, P= .012). Similarly in ALL, an ALC-15 <350 cells/microL predicts poor survival, with a 6-year RFS of 43% (HR 4.5, P= .002), whereas an ALC-15 >350 cells/microL predicts excellent outcome, with a 6-year OS of 87% (HR 0.2, P= .018). Importantly, ALC remains a strong predictor in multivariate analysis with known prognostic factors.

CONCLUSIONS

ALC is a simple, statistically powerful measurement for patients with de novo AML and ALL. The results, when combined with previous studies, demonstrate that ALC is a powerful new prognostic factor for a range of malignancies. These findings suggest a need for further exploration of postchemotherapy immune status and immune-modulating cancer therapies.

Towards a pathogenesis-oriented therapy of acute myeloid leukemia

Genetic and molecular techniques have provided increasing insights into the biology of acute myeloid leukemia (AML). These investigations showed that AML is not a homogeneous disease but a heterogeneous group of biologically different subentities. These subentities are currently primarily defined by cytogenetics by which three main subgroups can be discriminated: AML with balanced translocations, AML with unbalanced aberrations and AML without cytogenetically detectable aberrations. Within the latter group molecular alterations are identified in more than half of cases such as NPM mutations, FLT3 mutations, MLL duplications and mutations of CEBP-alpha. The clinical meaning of these findings is illustrated by substantial differences in response to therapy and long-term outcome. As demonstrated by the recent multicenter trial of the German AML Cooperative Group (AMLCG) and other studies intensification of induction therapy may improve the results in distinct subtypes but fails to do so in others. Therefore, new strategies need to be explored which incorporate the knowledge about the biology of AML to develop biology adapted treatment strategies. This process has just begun and is predominantly determined by the availability of new agents and their evaluation in clinical phase I and II studies. A variety of targets are currently explored and some trials have yielded promising results already. The step towards a biology adapted treatment of AML is long and requires the combined efforts of researchers, clinicians and the pharmaceutical industry. The first steps towards this goal have been taken and give rise to the hope for more effective and more specific therapies of AML.

Phase II Trial of Amsacrine Plus Intermediate-dose Ara-C (IDAC) with or without Etoposide as Salvage Therapy for Refractory or Relapsed Acute Leukemia

OBJECTIVE

The current trial attempted to evaluate the efficacy and toxicity of a salvage therapy consisting of amsacrine plus intermediate-dose Ara-C (IDAC) with or without etoposide for acute leukemia patients in refractory or relapsed states.

METHODS

A total of 51 patients with refractory or relapsed acute leukemia were included in the current trial. Twenty-nine patients with acute myeloid leukemia (AML) received a salvage therapy of amsacrine plus IDAC and etoposide, while 22 patients with acute lymphoblastic leukemia (ALL) received amsacrine plus IDAC.

RESULTS

The overall complete remission rate was 55% (45% for AML, 68% for ALL) and the median duration of overall survival was 144 days (95% confidence interval = 101-186 days). Grade 3, 4 infectious toxicities were observed in 43 patients (87%), while treatment-related toxicity, excluding infectious causes, included heart failure from myocarditis (n = 1) and central nervous system toxicity (n = 1).

CONCLUSION

A salvage therapy consisting of amsacrine plus IDAC with or without etoposide appears to be safe and an effective bridge therapy into a stem cell transplantation programme for patients with refractory or relapsed acute leukemia.

Functional analysis of apoptosis induction in acute myeloid leukaemia-relevance of karyotype and clinical treatment response

Deficiencies or structural defects of the apoptotic machinery have been postulated as a potential mechanism for a broad resistance of acute myeloid leukaemia (AML) blasts towards cytotoxic therapy comprising chemotherapeutic agents with diverse pharmacodynamic principles but also cell-mediated cytotoxicity of the graft-versus-leukaemia effect, for example, in the setting of allogeneic transplantation. This hypothesis was systematically tested by functionally analysing the early, intermediate and late events of the apoptotic process in primary AML (n = 31) blasts following activation of the intrinsic and extrinsic pathway of apoptosis (etoposide and cytarabine as DNA damaging agents, FAS-ligand as an activator of the death receptor pathway). Activation of the extrinsic pathway by FAS-ligand did not induce apoptosis in primary AML, instead the proapoptotic signal was shown to 'fade', even in the early phase of the apoptotic sequence. However, activation of the intrinsic pathway induced severe cytotoxicity in all samples that showed the characteristic features of typical apoptosis, with a prominent apoptotic volume decrease (blebbing) in the early phase, significant increases in caspase 3 activity (intermediate or effector phase) and breakdown of cellular energy production in the late phase of apoptosis. These characteristics did not differ between prognostically favourable versus unfavourable AML karyotypes or between clinically responding versus refractory AML--indicating that a functional apoptotic apparatus is present even in the unfavourable AML subgroups. Our data indicate that the mechanism for a broad clinical resistance is not a dysfunctional apparatus per se but rather the consequence of anti-apoptotic regulation impeding otherwise functional apoptotic machinery.

A phase II study of timed sequential therapy of acute myelogenous leukemia (AML) for patients over the age of 60: two cycle timed sequential therapy with topotecan, ara-C and mitoxantrone in adults with poor-risk AML

Acute myeloid leukemia (AML) in the elderly is a serious problem characterized by poor response to therapy and short survival. To improve response to therapy, a timed sequential therapy (TST) approach was designed utilizing topotecan, cytosine arabinoside (ara-C) and mitoxantrone based on multiple studies suggesting that topotecan and mitoxantrone are effective in older patients. Thirty-two adults, >or=60-year-old (median age 69) were included. None had favorable cytogenetics and 44% had and antecedent myelodysplastic syndrome (MDS) or 2 degrees AML. Fifty-nine percent achieved a complete response (CR). Median overall survival (OS) was 6.5 months (95% confidence interval (CI): 3.1-12.0 months; range, 15 days to 25.3 months). Disease-free survival (DFS) for the 19 patients achieving a CR was 7.7 months (95% CI: 6.1-13.7 months; range, 2.9-25.3 months). There were no differences in OS or DFS between cytogenetic or disease etiology groups. Although TST was well tolerated, long-term results in this group of patients are not satisfactory and new approaches are needed.

Targeting Vascular Endothelial Growth Factor for Relapsed and Refractory Adult Acute Myelogenous Leukemias

PURPOSE

Vascular endothelial growth factor (VEGF) promotes acute myelogenous leukemia (AML) cell growth and survival and may contribute to drug resistance. bevacizumab, an anti-VEGF monoclonal antibody, exhibits clinical activity against diverse malignancies when administered with cytotoxic chemotherapy. We conducted a Phase II clinical trial of bevacizumab administered after chemotherapy to adults with refractory or relapsed AML, using a timed sequential therapy (TST) approach.

EXPERIMENTAL DESIGN

bevacizumab 10 mg/kg was administered on day 8 after 1-beta-d-arabinofuranosylcytosine 2 g/m(2)/72 h beginning day 1 and mitoxantrone 40 mg/m(2) beginning day 4. In vivo laboratory correlates included AML cell VEGF receptor-1 (FLT-1) expression, marrow microvessel density, and free serum VEGF before and during TST with bevacizumab.

RESULTS

Forty-eight adults received induction therapy. Myelosuppression occurred in all of the patients similar to other TST regimens. Toxicities were decreased ejection fraction (6%), cerebrovascular bleed (4%), and mortality of 15%. Overall response was 23 of 48 (48%), with complete response (CR) in 16 (33%). Eighteen (14 CR and 4 partial response) underwent one consolidation cycle and 5 (3 CR and 2 partial response) underwent allogeneic transplant. Median overall and disease-free survivals for CR patients were 16.2 months (64%, 1 year) and 7 months (35%, 1 year). Marrow blasts demonstrated FLT-1 staining before bevacizumab and marked decrease in microvessel density after bevacizumab. VEGF was detected in pretreatment serum in 67% of patients tested, increased by day 8 in 52%, and decreased in 93% (67% undetectable) 2 h after bevacizumab.

CONCLUSIONS

In this single arm study, cytotoxic chemotherapy followed by bevacizumab yields a favorable CR rate and duration in adults with AML that is resistant to traditional treatment approaches. The clearance of marrow blasts in some patients after bevacizumab suggests that VEGF neutralization might result directly in leukemic cell death. The potential biological and clinical activity of bevacizumab in AML warrants additional clinical and laboratory study.

6-Thioguanine, cytarabine, and daunorubicin (TAD) and high-dose cytarabine and mitoxantrone (HAM) for induction, TAD for consolidation, and either prolonged maintenance by reduced monthly TAD or TAD-HAM-TAD and one course of intensive consolidation by sequential HAM in adult patients at all ages with de novo acute myeloid leukemia (AML): a randomized trial of the German AML Cooperative Group

PURPOSE

To examine the efficacy of prolonged maintenance chemotherapy versus intensified consolidation therapy for patients with acute myeloid leukemia (AML).

MATERIALS AND METHODS

Eight hundred thirty-two patients (median age, 54 years; range, 16 to 82 years) with de novo AML were randomly assigned to receive 6-thioguanine, cytarabine, and daunorubicin (TAD) plus cytarabine and mitoxantrone (HAM; cytarabine 3 g/m2 [age < 60 years] or 1 g/m2 [age > or = 60 years] x 6) induction, TAD consolidation, and monthly modified TAD maintenance for 3 years, or TAD-HAM-TAD and one course of intensive consolidation with sequential HAM (S-HAM) with cytarabine 1 g/m2 (age < 60 years) or 0.5 g/m2 (age > or = 60 years) x 8 instead of maintenance.

RESULTS

A total of 69.2% patients went into complete remission (CR). Median relapse-free survival (RFS) was 19 months for patients on the maintenance arm, with 31.4% of patients relapse-free at 5 years, versus 12 months for patients on the S-HAM arm, with 24.7% of patients relapse-free at 5 years (P =.0118). RFS from maintenance was superior in patients with poor risk by unfavorable karyotype, age > or = 60 years, lactate dehydrogenase level greater than 700 U/L, or day 16 bone marrow blasts greater than 40% (P =.0061) but not in patients with good risk by complete absence of any poor risk factors. Although a survival benefit in the CR patients is not significant (P =.085), more surviving patients in the maintenance than in the S-HAM arm remain in first CR (P =.026).

CONCLUSION

We conclude that TAD-HAM-TAD-maintenance first-line treatment has a higher curative potential than TAD-HAM-TAD-S-HAM and improves prognosis even among patients with poor prognosis.

Early blast clearance by remission induction therapy is a major independent prognostic factor for both achievement of complete remission and long-term outcome in acute myeloid leukemia: data from the German AML Cooperative Group (AMLCG) 1992 Trial

Risk assessment in acute myeloid leukemia (AML) using pretreatment characteristics may be improved by incorporating parameters of early response to therapy. In the 1992 trial of the German AML Cooperative Group (AMLCG), the amount of residual leukemic blasts in bone marrow was assessed one week after the first induction course (day 16 blasts). A total of 449 patients 16 to 76 years of age (median, 53 years) with de novo AML entered the trial and were evaluable. Treatment included TAD/HAM (thioguanine, cytosine arabinoside, and daunorubicin/high-dose cytosine arabinoside and mitoxantrone) double induction, TAD consolidation, and randomly either maintenance therapy or S-HAM consolidation. Cytogenetics were favorable, intermediate, unfavorable and not available in 10.0%, 48.3%, 13.1%, and 28.5%, respectively. Day 16 blasts ranged from 0% to 100% (median, 5%, mean +/- SD, 18.6 +/- 28.5%). Complete remission (CR) rate was 72.6%, 17.6% had persistent leukemia (PL), and 9.8% succumbed to hypoplastic death. Median overall survival (OS), event-free survival (EFS), and relapse-free survival (RFS) were 18, 9, and 15 months with 28.4%, 21.6%, and 30.1% at 5 years, respectively. As a continuous variable, day 16 blasts were related to CR rate (P < 0.0001), PL rate (P < 0.0001), OS (P < 0.0001), EFS (P < 0.0001), and RFS (P = 0.0049). Multivariate analyses identified the following parameters to be associated with the respective end points. CR rate: day 16 blasts (P <.0001), age (P =.0036), and LDH (P =.0072); OS: unfavorable cytogenetics (P <.0001), day 16 blasts (P <.0001), age (P <.0001), and LDH (P =.0040); EFS: unfavorable cytogenetics (P <.0001), LDH (P <.0001), day 16 blasts (P <.0001), and age (P =.0061); RFS: unfavorable cytogenetics (P <.0001), LDH (P <.0001), and day 16 blasts (P =.0359). The prognostic significance of day 16 blasts is independent of pretherapeutic parameters and predicts outcome even in patients achieving a CR.

Timed sequential chemotherapy with concomitant granulocyte colony-stimulating factor for high-risk acute myelogenous leukemia: a single arm clinical trial

BACKGROUND

The timed-sequential chemotherapy regimen consisting of etoposide, mitoxantrone and cytarabine (EMA) is an effective therapy for relapsed or refractory acute myelogenous leukemia (AML). We postulated that granulocyte colony-stimulating factor (G-CSF) might enhance the cytotoxicity of EMA by increasing the proportion of leukemic blasts in S-phase. We added G-CSF to EMA (EMA-G) for therapy of advanced high-risk AML patients.

METHODS

High-risk AML was defined as refractory, relapsed or secondary to either an antecedent hematologic disorder or exposure to cytotoxic agents. The patients were treated with one course of EMA-G consisting of mitoxantrone and cytarabine on days 1-3, and etoposide and cytarabine on days 8-10. G-CSF was started on day 4 and continued until absolute neutrophil count recovered.

RESULTS

Thirty patients were enrolled. The median age was 51 years (range, 25-75). Seventeen (61%) patients had unfavorable cytogenetic karyotypes. Twenty (69%) patients had secondary AML. Ten (34%) had relapsed disease. Four (14%) had refractory AML. Three (10%) patients died from febrile neutropenia and sepsis. Major non-hematologic toxicity included hyperbilirubimenia, renal insufficiency, mucositis, diarrhea, nausea and vomiting, skin rash. A complete remission was achieved in 13 (46%) patients. Median overall survival was 9 months (range, 0.5-66). Median relapse-free survival (RFS) for those who had a CR was 3 months (range, 0.5-63) with RFS censored at the time of allogeneic bone marrow transplantation or peripheral stem cell transplantation for 6 of the patients.

CONCLUSIONS

EMA-G is a safe and efficacious option for induction chemotherapy in advanced, high-risk AML patients. The activity of EMA may be increased if applied in patients with less advanced disease.

Treatment of refractory acute leukemia with timed sequential chemotherapy using topotecan followed by etoposide + mitoxantrone (T-EM) and correlation with topoisomerase II levels

A phase I/II clinical study evaluated 17 patients with refractory/recurrent acute leukemia treated with 1.5 mg/m2/day topotecan on days 1-3 followed by etoposide (100 mg/m2/day)+mitoxantrone (10 mg/m2/day) on days 4, 5 and 9, 10. Timed sequential chemotherapy using the topoisomerase I-inhibitor topotecan before the topoisomerase II-inhibitors, etoposide+mitoxantrone (T-EM) treatment is proposed to induce topoisomerase II protein levels and potentiate the cytotoxic activity of the topoisomerase II-directed drugs. Fourteen patients had refractory and three had recurrent acute leukemia. The majority of patients were heavily pre-treated with greater than three re-induction chemotherapy regimens. Ten patients responded to T-EM treatment (59%). Four of seventeen (24%) had a complete remission and one had a partial remission. Four additional patients (24%) who scored complete leukemia clearance had no evidence of disease with complete white and red blood cell recovery but with platelet counts less than 100,000. The lack of platelet recovery in one patient having a partial response was scored as a partial leukemia clearance. The toxicity profile included major non-hematological toxicity including grade 3 mucositis (29%) and neutropenic fever (65%). Paired measurements of intracellular levels of topoisomerase II isoforms alpha and beta in leukemia blast cells (bone marrow) collected before (day 0) and after topotecan treatment (day 4) showed that a relative increase of topoisomerase IIalpha (Topo IIalpha) > or = 40% strongly correlated with response after T-EM treatment. Increased Topo IIalpha levels also corresponded to increased DNA fragmentation. Two patients who had an increase of Topo IIalpha of 20-25% had either a PR or PLC while patients with a < 10% increase showed no response to T-EM treatment. We conclude that timed sequential chemotherapy using topotecan followed by etoposide+mitoxantrone is an effective regimen for patients with refractory acute leukemia, and demonstrate Topo IIalpha protein level increases after topotecan treatment.

Current status and perspectives of therapy for acute myeloid leukemia

Intensification of induction and postremission chemotherapies has resulted in a steady improvement in outcomes for adults with acute myeloid leukemia (AML) over the past two decades. The global response to initial therapy is now in the range of 60% to 80%, with 20% to 30% of patients experiencing long-term disease-free survival. Modern methodologies have revealed that cytogenetic aberrations are closely related to treatment outcome and have allowed subgroups of patients to be identified who have AML with a good, intermediate, or poor prognosis. The actions and interactions of cytogenetics and therapy in determining treatment outcome have been investigated in a series of clinical trials conducted by the German AML Cooperative Group. Evidence is presented that therapy and cytogenetics can independently influence outcome. It is hoped that our increasing understanding of the biological mechanisms that dictate disease characteristics will lead to improved outcomes for patients with AML.

Improved treatment results in high-risk pediatric acute myeloid leukemia patients after intensification with high-dose cytarabine and mitoxantrone: results of Study Acute Myeloid Leukemia-Berlin-Frankfurt-Münster 93

PURPOSE

To improve outcome in high-risk patients, high-dose cytarabine and mitoxantrone (HAM) was introduced into the treatment of children with acute myelogenous leukemia (AML) in study AML-BFM 93. Patients were randomized to HAM as either the second or third therapy block, for the purpose of evaluation of efficacy and toxicity.

PATIENTS AND METHODS

A total of 471 children with de novo AML were entered onto the trial; 161 were at standard risk and 310 were at high risk. After the randomized induction (daunorubicin v idarubicin), further therapy, with the exception of HAM, was identical in the two risk groups and also comparable to that in study Acute Myeloid Leukemia-Berlin-Frankfurt-Münster (AML-BFM) 87.

RESULTS

Overall, 387 (82%) of 471 patients achieved complete remission, and 5-year survival, event-free survival (EFS), and disease-free survival rates were 60%, 51%, and 62%, respectively. Idarubicin induction resulted in a significantly better blast cell reduction in the bone marrow on day 15. Estimated survival and probability of EFS were superior in study AML-BFM 93 compared with study AML-BFM 87 (P =.01, log-rank test). This improvement, however, was restricted to the 310 high-risk patients (remission rate and probability of 5-year EFS in study AML-BFM 93 v study AML-BFM 87: 78% v 68%, P =.007; and 44% v 31%, P =.01, log-rank test). Probability of 5-year EFS among standard-risk patients in study AML-BFM 93 was similar to that in study AML-BFM 87 (65% v 63%, P = not significant). Whether HAM was placed as the second or third therapy block was of minor importance. However, patients who received the less intensive daunorubicin treatment during induction benefited from early HAM.

CONCLUSION

Improved treatment results in children with high-risk AML in study AML-BFM 93 must be attributed mainly to the introduction of HAM.

Salvage therapy for refractory or relapsed acute lymphocytic leukemia

The overall prognosis for patients with relapsed or refractory adult ALL remains poor. Further insight into the biology of ALL is required, and novel therapeutic agents are needed to counter mechanisms of resistance. A palliative approach to the management of multiply relapsed or refractory ALL should be supplanted by enrollment into clinic trials to promote drug discovery. Monitoring of minimal residual disease may allow an earlier intervention before overt clinical relapse and improve outcome; prospective studies are needed. Attainment of a second or later CR should be followed by allogeneic BMT when feasible owing to the paucity of long-term survivors with salvage chemotherapy alone.

Mitoxantrone, etoposide, carboplatinum and ara-C combination therapy (MECA) in refractory and relapsed acute leukemia

The present study was undertaken to assess the feasibility, toxicity and antileukemic activity of sequential chemotherapy including mitoxantrone, etoposide, carboplatin and intermediate-dose cytarabine in adult patients with refractory and relapsed acute myelogenous (AML) or lymphoid (ALL) leukemia. Fifty-one patients with poor-risk AML and ALL received 64 courses of MECA therapy. The overall response in the entire group was 51% (43% complete remission). The stage of the disease (relapsed or primarily refractory) and the age of the patients did not strongly affect the response rate. MECA therapy was more effective in ALL than in AML, and in those patients who presented at salvage treatment with a bone marrow infiltration lower than 25% blasts. Hematological and extra-hematological toxicities were tolerable and there were 6 deaths related to the treatment (11%). The incidence of documented infectious episodes was 71%. MECA therapy is a safe treatment and has a high antileukemic activity in relapsed and primarily refractory AML or ALL.

Successful modulation of high-dose cytosine arabinoside metabolism in acute myeloid leukaemia by haematopoietic growth factors: no effect of ribonucleotide reductase inhibitors fludarabine and gemcitabine

High-dose cytosine arabinoside (AraC)-containing regimens have shown the highest antileukaemic efficacy of all currently used regimens in the treatment of acute myeloid leukaemia (AML). This study aimed at increasing the antileukaemic potential of high-dose AraC by raising intracellular levels of AraC triphosphate (AraCTP), which is the mediator of cytotoxicity, via biochemical modulation by inhibitors of ribonucleotide reductase (RR) or haematopoietic growth factors (HGFs). Blasts from patients with de novo AML were analysed for their formation of AraCTP under high-dose AraC conditions (20 microM over 3 h) without prior modulation (n = 47) after a 2-h pre-exposure with fludarabine (50 microg/ml) (n = 40) or gemcitabine (30 ng/ml) (n = 40) and after a 48-h pre-exposure to granulocyte colony-stimulating-factor (G-CSF; 100 ng/ml) (n = 27) or granulocyte-macrophage colony-stimulating-factor (GM-CSF; 100 U/ml) (n = 28). Unmodulated formation of AraCTP (median 239.8 ng/107 cells) could not be increased via modulation by gemcitabine (232.4 ng/107 cells) or fludarabine (247.8 ng/107 cells). The lack of effect of RR inhibitors was also observed for all other known metabolites of AraC [Ara-cytosine monophosphate (CMP), Ara-cytosine diphosphate (CDP), AraCDP-choline, Ara-uridine monophosphate (UMP), Ara-uridine diphosphate (UDP) and Ara-uridine triphosphate (UTP)]. In contrast, pre-exposure to HGFs led to significant increases in AraCTP formation (G-CSF 556.0 ng/107 cells, 2.31-fold increase, P < 0.001; GM-CSF 447.9 ng/107 cells, 1.87-fold increase, P < 0.0001). To establish the mechanism responsible for these effects, the activity of the rate-limiting enzyme of AraC metabolism, deoxycytidine kinase (dCK), was investigated (n = 33). In vivo exposure to GM-CSF led to increases in dCK activity from unmodulated values at 0 h (29.8 pmol/min/mg protein) to 34.3 pmol/min/mg protein at 24 h (1.15-fold increase) and 54.5 pmol/min/mg protein at 48 h (1. 83-fold increase). The raise in dCK activity over 48 h was significant (P < 0.013).

Multivariate analysis of prognostic factors in patients with refractory and relapsed acute myeloid leukemia undergoing sequential high-dose cytosine arabinoside and mitoxantrone (S-HAM) salvage therapy: relevance of cytogenetic abnormalities

To improve the basis for the stratification of patients with refractory and relapsed acute myeloid leukemia (AML) univariate and multivariate analyses of prognostic factors were performed in 254 patients (median age 50 years, range 18-74) undergoing S-HAM salvage chemotherapy during two consecutive prospective trials of the German AML Cooperative Group. In a multivariate analysis, duration of the first complete remission (CR) was the only factor associated with time to treatment failure (P = 0.0223). Disease-free survival was influenced by a short duration of the first CR of less than 6 months (P = 0.0001), WBC (P = 0.0018), blast count (P = 0.0037), and neutrophil count (P = 0.0119). The achievement of CR was related to the hemoglobin level only (P = 0.0457), the early death rate was related to age only (P = 0.0109), and survival was related to the bilirubin level only (P = 0.0166). In the subgroup of 104 patients in whom additional karyotype analyses were performed prior to first-line therapy unfavorable chromosome abnormalities were associated with a lower CR rate (univariate analysis, P = 0.0342; CR 24% vs 53%) and were the only factor related to survival. These analyses warrant the further evaluation of the impact of cytogenetic abnormalities on the outcome of patients with advanced AML in order to improve the characterization according to duration of first CR and to WBC of distinct subgroups of patients with differing prognoses as a basis for stratification in future trials.

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.