A randomized study of intermediate versus conventional-dose cytarabine as intensive induction for acute myelogenous leukaemia

Improved Treatment Outcomes With Modified Induction Therapy in Acute Myeloid Leukemia (AML): A Retrospective Observational Study From a Regional Cancer Center

BACKGROUND

The aggressive, genetically diverse group of malignant illnesses known as acute myeloid leukemia (AML) is characterized by clonally related myeloblast invasion of the bone marrow, blood, and other organs. The treatment regimen plays a crucial role in the management of AML, and it is associated with poor overall survival and enhanced risk of relapse. Induction therapy with a 7+3 DA regimen (daunorubicin + ara-C) has been the treatment of choice for young and fit patients.

OBJECTIVE

To evaluate the effect of dose modification in young and fit patients for a modified treatment regimen.

METHODS

This was a retrospective, observational study of AML patients to analyze the outcomes of modified induction therapy in AML patients enrolled at Dr. B. Borooah Cancer Institute, Guwahati, Assam, India, from October 2021 to March 2022. The outcomes of modified induction therapy with intensive chemotherapy (modified 7+3 DA) and low-intensity chemotherapy decitabine (10 days) and venetoclax + azacytidine (seven days) were considered after the first two cycles or 60 days, whichever was earlier.

RESULTS

Data from 31 patients with de-novo AML was analyzed; the median age of the patients was 41 years (range: 2-71 years), and the male-to-female ratio was 1.8. There were seven patients in the pediatric age group (2-13 years), and 19%, 65%, and 13% of patients belonged to favorable, intermediate, and high-risk groups, respectively. With regards to modified induction therapy (n=31), 20 (65%) patients received modified "7+3 DA", nine (29%) received hypomethylating agents (HMA, decitabine only), and two patients received HMA (azacitidnie) + venetoclax. Additionally, 23/31 patients completed at least two cycles of induction therapy. Overall, 60 day-induction mortality was 13%, and the complete remission (CR) and partial remission (PR) rates were 48% and 26%, respectively. In patients who received modified "7+3 DA", the CR rate was 55%.

CONCLUSIONS

The notable reduction in deaths due to infections observed in our study suggests that centers with limited resources for preventing neutropenic complications during induction therapies in AML patients could consider adopting this modified regimen.

Improved Post remission survival of non- favorable risk Acute Myelogenous Leukemia (AML) patients following initial remission induction therapy with FLAG+/-Idarubicin versus 3 + 7 (Anthracycline + Cytarabine)

The fludarabine, high dose cytarabine and G-CSF with or without idarubicin combination regimen, referred to as FLAG+/-Ida, is commonly used as a salvage regimen for relapsed/refractory AML but its use as initial induction therapy has been more limited. The impact of choice of induction regimen on post remission survival remains unclear. We retrospectively analyzed 304 consecutive AML patients, with non-favorable NCCN risk who received initial treatment at our center with either 7 + 3 (n = 86) or FLAG+/-Ida (n = 218). Patients in the FLAG+/-Ida group were more likely to achieve remission after one course of induction (74 % vs 62 %, p < 0.001) and had a faster time to achieve CR (30 days vs 37.5, p < 0.001) compared to 7 + 3. The time from diagnosis to transplant was shorter among CR patients after FLAG+/-Ida compared to 7 + 3 (115 vs. 151 days, p < 0.003). The 3-year post-remission OS and DFS was significantly better for patients receiving FLAG-Ida at 54 % and 49 % compared to 39 % and 32 % for 7 + 3 respectively (P = 0.01). Factors associated with post-remission survival included age at CR1, NCCN risk, induction regimen (FLAG+/-Ida vs 3 + 7 h 0.62, p = 0.01) and receipt of HCT. Our data, with the limitations inherent to a retrospective analysis, shows that achieving CR after FLAG+/-Ida has better post remission survival than 7 + 3.

Daunorubicin and cytarabine for certain types of poor-prognosis acute myeloid leukemia: a systematic literature review

INTRODUCTION

Induction chemotherapy based on anthracyclines and cytarabine (Ara-C) combination remains the standard of care for acute myeloid leukemia (AML) patients who are considered candidate for intensive and curative approaches. However, the toxicity of this regimen is high, with disappointing clinical outcomes among the so-called poor-prognosis AML subsets, which generally refer to patients with adverse cytogenetic risk, secondary AML including therapy-related AML, poor-prognosis mutations, especially FLT3-ITD, and relapse/refractory AML. Areas covered: To the best of our knowledge, the role and efficacy of 7 + 3 schedules containing daunorubicin (DNR) and Ara-C for certain types of poor-prognosis AML has not been systematically assessed. A critical approach to the role of DNR and Ara-C induction could be relevant to establish which patients should be enrolled in clinical trials using novel therapies. Expert commentary: In this regard, a recent randomized clinical trial (RCT) showed improved results in older patients with sAML or high-risk cytogenetics who received CPX-351 compared with standard 7 + 3 combination. We perform a systematic literature review to analyze the clinical outcomes reported with DNR plus Ara-C regimens in adult patients with poor-prognosis AML, the use of liposomal formulations of DNR and Ara-C and the RCTs which compared standard 7 + 3 with the addition of a third drug.

Analysis of the prolonged infusion of DFP-10917, a deoxycytidine analog, as a therapeutic strategy for the treatment of human tumor xenografts in vivo

2'-C-cyano-2'-deoxy-1-β-D-arabino-pentofranocyl-cytosine (DFP-10917, CNDAC) is a 2'-deoxycytidine analog with antitumor activity against various tumor cells. However, a clinically available therapeutic regimen for this compound needs to be established and its functional mechanisms in relation to the dosing schedule need to be clarified. In this study, we evaluated the antitumor activity and toxicity of DFP-10917 by varying the dose and administration schedule in human solid tumor and leukemia xenografts in vivo. Compared to a 1-day infusion with a high-dose of DFP-10917 (30 mg/kg/day), a prolonged 14-day infusion with a low-dose (4.5 mg/kg/day) exerted superior tumor growth inhibitory effects without decreasing the body weights of mice in our human tumor xenograft model. In addition, we found that a 14-day infusion of low-dose DFP-10917 markedly prolonged the lifespan of nude mice bearing both acute leukemia and ovarian cancer cell-derived tumors. On the other hand, gemcitabine (GEM) and cytosine arabinoside (Ara-C), which are similar deoxycytidine analogs and are widely used clinically as standard regimens, exerted less potent antitumor effects than DFP-10917 on these tumors. To elucidate the possible functional mechanisms of the prolonged infusion of DFP-10197 compared with that of GEM or Ara-C, the rate of DNA damage in CCRF-CEM and HeLa cells treated with DFP-10917, Ara-C and GEM was detected using a comet assay. DFP-10917, at a range of 0.05 to 1 µM, induced a clear tailed-DNA pattern in both the CCRF-CEM and HeLa cells; Ara-C and GEM did not have any effect. It was thus suggested that a low concentration and long-term exposure to DFP-10917 aggressively introduced the fragmentation of DNA molecules, namely the so-called double-strand breaks in tumor cells, leading to potent cytotoxicity. Moreover, treatment with DFP-10917 at a low-dose with a long-term exposure specifically increased the population of cells in the G2/M phase, while GEM reduced this cell population, suggesting a unique function (G2/M arrest) of DFP-10917. On the whole, our findings indicate that the prolonged infusion of low-dose DFP-10917 mainly displays a novel functional mechanism as a DNA-damaging drug and may thus prove to be useful in the treatment of cancer patients who are resistant to other cytosine nucleosides, or in patients in which these other nucleosides have been shown to be ineffective.

A multicenter trial of myeloablative clofarabine and busulfan conditioning for relapsed or primary induction failure AML not in remission at the time of allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic cell transplantation (HCT) may produce long-term survival in AML after relapse or primary induction failure (PIF). However, outcomes of HCT performed for AML not in remission are historically poor given high relapse rates and transplant-related mortality. Preliminary studies suggest conditioning with clofarabine and myeloablative busulfan (CloBu4) may exert significant anti-leukemic effects without excessive toxicity in refractory hematologic malignancies. A prospective multicenter phase II trial was conducted to determine the efficacy of CloBu4 for patients proceeding directly to HCT with AML not in remission. Seventy-one patients (median age: 56 years) received CloBu4. At day 30 after HCT, 90% achieved morphologic remission. The incidence of non-relapse mortality and relapse at 2 years was 25% and 55%, respectively. The 2-year overall survival (OS) and event-free survival (EFS) were 26% and 20%, respectively. Patients entering HCT in PIF had significantly greater EFS than those in relapse (34% vs 8%; P<0.01). Multivariate analysis comparing CloBu4 with a contemporaneous cohort (Center for International Blood and Marrow Transplantation Research) of AML not in remission receiving other myeloablative conditioning (n=105) demonstrated similar OS (HR: 1.33, 95% confidence interval: 0.92-1.92; P=0.12). HCT with myeloablative CloBu4 is associated with high early response rates and may produce durable remissions in select patients with AML not in remission.

Benefit of high-dose daunorubicin in AML induction extends across cytogenetic and molecular groups

The initial report of the Eastern Cooperative Oncology Group-American College of Radiology Imaging Network Cancer Research Group trial E1900 (#NCT00049517) showed that induction therapy with high-dose (HD) daunorubicin (90 mg/m(2)) improved overall survival in adults <60 years old with acute myeloid leukemia (AML); however, at initial analysis, the benefit was restricted to younger patients (<50 years) and patients without unfavorable cytogenetics or aFLT3-ITD mutation. Here, we update the results of E1900 after longer follow-up (median, 80.1 months among survivors), focusing on the benefit of HD daunorubicin on common genetic subgroups. Compared with standard-dose daunorubicin (45 mg/m(2)), HD daunorubicin is associated with a hazard ratio (HR) for death of 0.74 (P= .001). Younger patients (<50 years) benefited from HD daunorubicin (HR, 0.66;P= .002), as did patients with favorable and intermediate cytogenetics (HR, 0.51;P= .03 and HR, 0.68;P= .01, respectively). Patients with unfavorable cytogenetics were shown to benefit from HD daunorubicin on multivariable analysis (adjusted HR, 0.66;P= .04). Patients with FLT3-ITD (24%),DNMT3A(24%), and NPM1(26%) mutant AML all benefited from HD daunorubicin (HR, 0.61,P= .009; HR, 0.62,P= .02; and HR, 0.50,P= .002; respectively). HD benefit was seen in the subgroup of older patients (50-60 years) with the FLT3-ITD or NPM1 mutation. Additionally, the presence of an NPM1 mutation confers a favorable prognosis only for patients receiving anthracycline dose intensification during induction.

Diagnosis and Therapy of Acute Myeloid Leukemia in the Era of Molecular Risk Stratification

The diagnosis and risk stratification of acute myeloid leukemia (AML) primarily rely on morphologic analysis and assessment of karyotype by chromosome banding analysis. For decades, standard AML induction therapy has utilized the combination of anthracyclines and cytarabine. Despite the use of postremission therapy, less than half of patients with AML will be cured of their disease. Allogeneic hematopoietic stem cell transplantation combines cytoreductive chemotherapy with adoptive immunotherapy and may cure patients who fail chemotherapy alone. Recent advances in next-generation sequencing have yielded important insights into the molecular landscape of AML with normal karyotype. Integrated prognostic models incorporating somatic mutation analyses may outperform prediction based on conventional clinical and cytogenetic factors alone. We review the evolution of risk profiling of AML from the cytogenetic to molecular era and describe the implications for AML diagnosis and postremission therapy.

Timed-sequential chemotherapy as induction and/or consolidation regimen for younger adults with acute myelogenous leukemia

Increasing the intensity of induction chemotherapy has generated considerable recent interest in the treatment of acute myeloid leukemia. Achieving complete remission is a sine qua non condition for prolonged disease-free survival and may affect long-term outcome. In this setting, administering a repeat course of induction shortly after completion of the first course, known as timed-sequential chemotherapy (TSC), has been tested and may lead to an improved long-term outcome. Whether these results are due to the biologic recruitment of cell cycle-specific agents is unknown. However, this strategy to intensify induction may lead to more profound myelosuppression and to potential toxicities. Here we review the results of timed-sequential chemotherapy, used as induction regimen in de novo, relapsed or refractory AML or used as post-remission therapy, and compare them with those from other types of regimens.

Acute myeloid leukemia: potential for new therapeutic approaches targeting mRNA translation pathways

Despite advances in molecular research related to acute myeloid leukemia (AML) and a better understanding of the mechanisms of leukemogenesis and pathophysiology of the disease, the pharmacological agents used in the treatment of AML have remained essentially unchanged for the last three decades. Advances in the clinical management of AML patients have been achieved by defining better molecular prognostic markers, but there remains a need for new targeted drugs that disrupt non-overlapping pathways in leukemia cells. The mTOR cellular cascade is critical for cell metabolism, growth, proliferation and survival. Extensive preclinical work suggests that targeting mTOR may provide a powerful approach to block AML precursor cells, while other findings suggest enhanced antileukemic effects by combining mTOR inhibitors with traditional chemotherapy. Such combinations may increase antileukemic responses further, offering unique ways to overcome leukemic cell resistance and to eliminate primitive leukemic precursors.

Retrospective analysis of 119 cases of pediatric acute promyelocytic leukemia: Comparisons of four treatment regimes

Clinical trials have demonstrated that pediatric acute promyelocytic leukemia (APL) is highly curable. Small-scale studies have reported on the treatment of APL using one or two treatment regimes. Here, we report a multiple center-based study of 119 cases of pediatric APL treated with four regimes based on all-trans-retinoic acid (ATRA). We retrospectively analyzed the clinical characteristics, laboratorial test results and treatment outcome of the pediatric APL patients. Regime 1 used an in-house developed protocol, regime 2 was modified from the PETHEMA LPA99 protocol, regime 3 was modified from the European-APL93 protocol, and regime 4 used a protocol suggested by the British Committee for Standards in Haematology. The overall complete remission rates for the four regimes were 88.9, 87.5, 97.1 and 87.5%, respectively, which exhibited no statistical difference. However, more favorable results were observed for regimes 2 and 3 than regimes 1 and 4, in terms of the estimated 3.5-year disease-free survivals, relapse rates, drug toxicity (including hepatotoxicity, cardiac arrhythmia, and differentiation syndrome) and sepsis. In conclusion, the overall outcomes were more favorable after treatment with regimes 2 and 3 than with regimes 1 and 4, and this may have been due to the specific compositions of regimes 2 and 3.

A randomized trial comparing standard versus high-dose daunorubicin induction in patients with acute myeloid leukemia

We conducted a phase 3 randomized trial comparing 2 different doses of daunorubicin as induction chemotherapy in young adults (60 years of age or younger) with acute myeloid leukemia (AML). Of 383 patients who were analyzed, 189 received standard-dose daunorubicin (SD-DN, 45 mg/m² per day times 3 days) and 194 received high-dose daunorubicin (HD-DN, 90 mg/m² per day times 3 days) in addition to cytarabine (200 mg/m² per day times 7 days) to induce complete remission (CR). The CR rates were 72.0% in the SD-DN arm and 82.5% in the HD-DN arm (P = .014). At a median follow-up of 52.6 months, overall (OS) and event-free (EFS) survival were higher in the HD-DN arm than in the SD-DN arm (OS, 46.8% vs 34.6%, P = .030; EFS, 40.8% vs 28.4%, P = .030). Differences in CR rate and both OS and EFS remained significant after adjusting for other variables (CR, hazard ratio [HR], 1.802, P = .024; OS, HR, 0.739, P = .032; EFS, HR, 0.774, P = .048). The survival benefits of HD-DN therapy were evident principally in patients with intermediate-risk cytogenetic features. The toxicity profiles were similar in the 2 arms. In conclusion, HD-DN improved both the CR rate and survival duration compared with SD-DN in young adults with AML. This study is registered at www.clinicaltrials.gov as #NCT00474006.

Induction and postremission strategies in acute myeloid leukemia: what is new?

PURPOSE OF REVIEW

Induction followed by postremission therapy is recognized as the main road toward cure in acute myeloid leukemia (AML). Induction approach has not changed substantially for many years. Despite identifying numerous heterogeneous factors in AML, bench-derived insights are sluggishly translated into clinical protocols. In the current review, advances in intensified dose induction protocols, risk stratification, and disease monitoring are presented. Some promising as well as disappointing agents used for tailoring and targeting therapies in AML are also discussed.

RECENT FINDINGS

Intensifying anthracycline dose in young AML patients was recently shown to improve induction results. Importantly, maximal doses in induction have been shown to be safe also in older adults, negating a common perception that too often led to attenuation of induction therapy in this population. Novel targeted agents and the explosive number of newly identified prognostic factors or disease-specific biomarkers are promoting AML therapy toward a more personalized future.

SUMMARY

Survival of AML patients is constantly improving. High doses of 'old drugs' for chemotherapy induction, followed by a postremission combination of chemotherapy and novel targeted agents may hold the key for cure. Disease-specific molecular abnormalities may play a role in monitoring and guiding therapy.

New trends in the standard of care for initial therapy of acute myeloid leukemia

In younger patients with acute myeloid leukemia (AML), initial treatment has provided very good control of the disease. Induction therapy has used combination chemotherapy, with anthracycline and cytarabine as the foundation. Recent trials support dose intensification of anthracycline in induction. Intensive postremission therapy further contributes to improving survival. The addition of targeted therapy with gemtuzumab ozogamicin to standard therapy has not improved on these outcomes. Newer agents targeted to specific molecular abnormalities or survival mechanisms in the leukemic cell are being studied as future additions to the current standard therapy.

Anthracycline dose intensification in acute myeloid leukemia

BACKGROUND

In young adults with acute myeloid leukemia (AML), intensification of the anthracycline dose during induction therapy has improved the rate of complete remission but not of overall survival. We evaluated the use of cytarabine plus either standard-dose or high-dose daunorubicin as induction therapy, followed by intensive consolidation therapy, in inducing complete remission to improve overall survival.

METHODS

In this phase 3 randomized trial, we assigned 657 patients between the ages of 17 and 60 years who had untreated AML to receive three once-daily doses of daunorubicin at either the standard dose (45 mg per square meter of body-surface area) or a high dose (90 mg per square meter), combined with seven daily doses of cytarabine (100 mg per square meter) by continuous intravenous infusion. Patients who had a complete remission were offered either allogeneic hematopoietic stem-cell transplantation or high-dose cytarabine, with or without a single dose of the monoclonal antibody gemtuzumab ozogamicin, followed by autologous stem-cell transplantation. The primary end point was overall survival.

RESULTS

In the intention-to-treat analysis, high-dose daunorubicin, as compared with a standard dose of the drug, resulted in a higher rate of complete remission (70.6% vs. 57.3%, P<0.001) and improved overall survival (median, 23.7 vs. 15.7 months; P=0.003). The rates of serious adverse events were similar in the two groups. Median follow-up was 25.2 months.

CONCLUSIONS

In young adults with AML, intensifying induction therapy with a high daily dose of daunorubicin improved the rate of complete remission and the duration of overall survival, as compared with the standard dose. (ClinicalTrials.gov number, NCT00049517.)

Prognostic features for response and survival in elderly patients withde novoacute myeloid leukemia treated with mitoxantrone and intermediate dose cytarabine

Forty-three fit elderly patients with de novo acute myeloid leukemia (AML) received chemotherapy with mitoxantrone and intermediate dose cytarabine (MIDAC) in a phase II clinical trial conducted by the Australasian Leukaemia and Lymphoma Group. The main aim of the study was to evaluate the tolerability and efficacy of MIDAC in inducing durable remissions. While the chemotherapy was generally well tolerated, less than half the patients achieved complete remission (CR) after induction and many of those in CR could not receive planned consolidation cycles. The median overall survival for all patients was 6.5 months and the median disease-free survival for those achieving CR was 8.3 months. Only 2 patients survived beyond 4 years. Factors significantly associated with shorter survival were adverse cytogenetics, marrow dysplasia and increasing age. These results suggest that only selected elderly patients with AML are likely to benefit from aggressive chemotherapy and that novel therapies are required to improve the poor prognosis of this group.

Chemotherapy of acute leukemia in adults

BACKGROUND

General therapeutic options for adult patients with acute leukemia are reviewed and specific new treatment strategies are described.

OBJECTIVE

Treatment results and controversial issues on current and future antileukemic strategies are discussed.

METHODS

Data in this review came from the published literature.

RESULTS/CONCLUSION

In the past years, striking new developments have been noticeable in the treatment of adult acute leukemia. However, the overall outcome of adult acute leukemia remains poor, particularly in older patients. Intensive chemotherapy remains the standard for leukemia treatment but several approaches using new cytotoxic agents seem promising. Therapeutic targeting of specific biologic abnormalities present in the leukemia cell population might, in a near future, improve outcome of adult leukemia patients.

Drug delivery in acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia was among the first malignancies to be cured by drug therapy alone, but overall survival rates remain unsatisfactory and have changed little over the past 20 years. Conventional chemotherapeutic regimens, which almost invariably include cytarabine and anthracyclines, are untargeted, and more specific therapies are needed.

OBJECTIVE

We have chosen acute myeloid leukemia as a disease prototype to review established and novel targeted approaches in leukemia treatment.

METHODS

Our selection of the reviewed literature focused on drug delivery aspects.

CONCLUSION

While the toxicity profile of chemotherapeutics has been improved by liposomal formulations and antibody conjugation for leukemia-directed uptake, their efficacy has probably not changed significantly. Drugs with an alternative mode of action, including kinase inhibitors, hold great promise. Further improvements may result from the characterization of novel acute myeloid leukemia (AML) cell surface receptors and of leukemic stem cells, as well as from the design of leukemia-targeted gene therapy vectors.

The development of a novel protocol for the treatment of de novo childhood acute myeloid leukemia in a single institution in Taiwan

From November 1, 1995 to July 31, 2004, 49 children with de novo acute myeloid leukemia (AML) were treated at our institution. One patient who was treated by a different protocol was excluded. In total, 48 patients with de novo AML were enrolled in this study. Forty-two patients with AML other than acute promyelocytic leukemia (non-APL) were treated consecutively with 2 novel protocols: Mackay Memorial Hospital (MMH)-AML-96, designed as a pilot phase, and Taiwan Pediatric Oncology Group (TPOG)-AML-97A, on the basis of MMH-AML-96 with minor modifications. Six patients with APL were treated consecutively with 2 protocols, TPOG-APL-97 and APL-2001. As of July 31, 2006, the remission rates were 79%, 92%, and 98% after 1, 2, and 3 courses of induction therapy, respectively. The 5-year overall survival was 64%+/-6.9% (SE), and the 5-year event-free survival was 60%+/-7.1%; for non-APL AML, the rates were 62%+/-7.5% and 59%+/-7.6%; for APL, 83+/-15.2 and 67+/-19.3%. Among the factors analyzed, a complete remission achieved after 1 course of induction therapy, lactate dehydrogenase <500 IU/L at diagnosis, patients without invasive fungal infection during chemotherapy, and male sex were associated with a favorable outcome.

Homoharringtonine in combination with cytarabine and aclarubicin resulted in high complete remission rate after the first induction therapy in patients with de novo acute myeloid leukemia

To assess the efficacy and toxicity of HAA regimen (homoharritonine 4 mg/m2/day, days 1-3; cytarabine 150 mg/m2/day, days 1-7; aclarubicin 12 mg/m2/day, days 1-7) as an induction therapy in the treatment of de novo acute myeloid leukemia (AML), 48 patients with newly diagnosed AML, aged 35 (14-57) years, were entered into this clinical study. The median follow-up was 26 months. Eighty-three percent of patients achieved complete remission (CR), and the first single course of induction HAA regimen resulted in CR rate of 79%. The CR rate of 100, 82 and 33% were achieved in patients with favorable, intermediate and unfavorable cytogenetics, respectively. For all patients who achieved CR, the median time from the initiation of the induction therapy to the evaluation of the remission status was 32 days. For all patients, the estimated 3 years overall survival (OS) rate was 53%, whereas for patients with M5, the estimated OS rate at 3 years was 75%. The toxicities associated with HAA regimen were acceptable, and the most common toxicity was infection. This study suggested that HAA regimen might be a well-tolerable, effective induction regimen in young adult patients with AML.

Modeling the Pharmacodynamics of Highly Schedule-Dependent Agents: Exemplified by Cytarabine-Based Regimens in Acute Myeloid Leukemia

BACKGROUND

Many agents in antineoplastic chemotherapy are highly schedule dependent. Therefore, variables such as total dose and also the area under the curve (AUC) that are schedule insensitive are generally insufficient to adequately represent treatment strength.

PURPOSE

To establish a descriptor of treatment strength that takes into account the differential contribution of plasma concentrations (C) and exposure times (T) towards the cytotoxic effect and to investigate whether such a pharmacodynamically weighed descriptor is better correlated to the clinical effect than conventional variables.

PATIENTS AND METHODS

The paradigm "C(N) x T = constant" (for an isoeffect) incorporates a weighing factor N (concentration coefficient) into the conventional description of the AUC that quantitates the differential contribution of C and T towards the cytotoxic effect. N was to be numerically derived from a multitude of in vitro isoeffect analyses of the major agents in acute myeloid leukemia (AML) therapy from patient samples (n = 57).

RESULTS

For cytarabine, N was 0.45, numerically expressing the substantially higher relevance of T versus C for its cytotoxic effect. In a meta-analysis of 49 study arms involving >10,000 patients, neither total dose, dose intensity, nor AUC was correlated to the clinical effect. However, when AUC was pharmacodynamically weighed (N-weighed AUC, N-AUC = C(0.45) x T), this new descriptor was highly significantly correlated to the clinical effect (P < 0.001).

CONCLUSION

The N-AUC concept is able to characterize schedule-dependent agents and is the only descriptor of cytarabine treatment strength actually correlated to the clinical effect in AML.

Timed-sequential chemotherapy with concomitant granulocyte colony-stimulating factor for newly diagnosed de novo acute myelogenous leukemia

EMA, consisting of etoposide, mitoxantrone, and cytarabine, is a timed-sequential chemotherapy (TSC) regimen and an efficacious option for induction treatment of acute myelogenous leukemia (AML). Hematopoietic growth factors (HGFs) have been shown to recruit leukemic blasts into cell cycle. We postulated the addition of granulocyte colony-stimulating factor (G-CSF) to EMA (EMA-G) might enhance treatment efficacy. EMA-G consisted of mitoxantrone on days 1-3, cytarabine on days 1-3 and 8-10, etoposide on days 8-10, and G-CSF from day 4 until absolute neutrophil count (ANC) >500/microl. In total, 28 patients were enrolled. All patients had newly diagnosed de novo AML. The median age was 42 years. Of the 27 patients with cytogenetic analysis, six had favorable karyotype, 18 intermediate karyotype, and three unfavorable karyotype. The median follow-up was 37.5 months. The median time for both ANC recovery and last platelet transfusion was 26 days. The toxicities associated with this regimen were no more than those expected with the standard chemotherapy. In all, 24 (86%) patients achieved complete remission (CR), three (11%) patients had no response, and one patient died within 24 h of induction therapy before response could be evaluated. Of the 24 patients who achieved CR, 22 received high-dose cytosine arabinoside and two received allogeneic bone marrow transplant as initial postremission therapy. For the whole cohort, the estimated 3-year survival rate was 67%. The median relapse-free survival was 30.5 months. We conclude that EMA-G regimen is a safe regimen and administration of G-CSF during and after induction treatment is not associated with prolongation of marrow aplasia or acceleration of leukemia relapse. It is efficacious for induction therapy for newly diagnosed de novo AML. A high CR rate can be achieved with only one course of this chemotherapy.

Salvage therapy in refractory acute myeloid leukemia: prediction of outcome based on analysis of prognostic factors

Acute myeloid leukemia (AML) non-responsive to initial chemotherapy is generally of poor prognosis. High-dose cytarabine (HD-AraC) has been proposed as salvage therapy in combination with amsacrine. The aim of the current study was first to assess the toxicity and the efficacy of such a combination therapy, and secondly to determine prognostic factors allowing to predict whom patients could benefit of such a treatment. Out of 91, 45 patients referred to our institution have been treated by HD-AraC (3 g/m(2)/12h from day 1 to 4) combined with amsacrine (90 mg/m(2) per day from day 5 to 7) as a salvage regimen. Forty-five of the 91 patients (49%, 95% confidence interval (CI): 39-60%) achieved complete remission (CR). Thirty-five patients were refractory to the salvage therapy and 11 patients died from toxicity during aplasia. Median disease-free survival (DFS) was 11.5 months (95% CI: 6-16 months). After CR achievement, 26 patients received consolidation therapy according to the protocol in which they were included. Nineteen patients with an HLA-identical sibling donor underwent allogeneic bone marrow transplantation. At time of analysis, 27 of the 45 patients (60%) who achieved CR have relapsed. Median overall survival (OS) was 7.5 months (95% CI: 6-15 months). There was 12 long survivors (13%). In univariate analysis, initial karyotype was the main prognostic factor as well as in terms of CR achievement (P=0.002) than in terms of DFS (P=0.01) or OS (P=0.009). CR achievement was negatively influenced by higher WHO performance status index (P=0.006), higher LDH level (P=0.02), and higher CD34 expression by leukemic cells (P=0.03) at diagnosis, and presence of circulating blasts (P=0.001), platelet count <80 x 10(9)/l (P=0.0001), and polymorphonuclear (PMN) percentage <30% (P=0.01) at time of starting salvage therapy. DFS was negatively influenced by secondary AML (P=0.01), weight loss > or =5% (P=0.03), and higher white blood cell (WBC) count (P=0.03) at time of diagnosis. Age over 60 years (P=0.002), prior history of toxic exposure (P=0.01), higher CD34 expression (P=0.02), weight loss > or =5% (P=0.006), and WHO performance status index > or =2 (P=0.01) at diagnosis, and platelet count <80 x 10(9)/l (P=0.02) at time of salvage therapy were the main prognostic factors associated with shorter OS. In multivariate analysis, karyotype grouping at diagnosis (P=0.006) and blood count before salvage therapy (P=0.001) were of prognostic value for CR achievement. Karyotype remained of prognostic value for DFS and OS (P=0.007 and <0.0001, respectively).We conclude that HD-AraC combined with amsacrine was as a useful salvage regimen in AML non-responding to a first intensive course of chemotherapy. Using objective parameters of proven significance (karyotypic grouping and blood count before salvage), we devised a prognostic system of immediate clinical utility for prognostic stratification and risk-adapted therapeutic choices. Patients with favorable risk cytogenetics and those with intermediate risk cytogenetics and favorable blood count (PMN > or =30%, no circulating blasts, and platelet count > or =80 x 10(9)/l) before salvage therapy had a similar outcome than those achieving CR after only one course of chemotherapy. All other patients displayed a poor outcome. This suggests their orientation at an earlier time to alternate therapeutic programs based on investigational drugs.

Interaction of cytosine arabinoside and lovastatin in human leukemia cells

Cytosine arabinoside (ara-C) is widely used for the treatment of leukemias and displays significant toxicities. Lovastatin, an HMG-CoA reductase inhibitor, is extensively used to treat hypercholesterolemia. To determine whether lovastatin could augment ara-C's activity we have examined their effects in the human erythroleukemia K562 cell line and the ara-C resistant ARAC8D cell line. A synergistic interaction between the two drugs was found. We have demonstrated that the interaction does not occur at the level of RAS but may involve lovastatin's effect of downregulating MAPK activity and preventing ara-C-induced MAPK activation. These studies represent the first description of a potentially beneficial interaction between lovastatin and ara-C that could be applied to the treatment of human leukemia.

Long-term outcome after allogeneic hematopoietic stem cell transplantation for advanced stage acute myeloblastic leukemia: a retrospective study of 379 patients reported to the Société Française de Greffe de Moelle (SFGM)

To assess the place of allogeneic hematopoietic stem cell transplantation (HSCT) in the advanced stage of acute myeloid leukemia (AML), we retrospectively analyzed 379 consecutive patients who underwent allogeneic HSCT for advanced AML. The median follow-up of the entire cohort was 7.5 years. Sixty-nine patients (18%) were transplanted with primary resistant disease. Three hundred and ten (82%) were relapsed patients, 94 (30%) of whom were in untreated relapse, 67 (22%) in refractory relapse and 149 (48%) in 2nd or 3rd complete remission at time of transplantation. The 5-year probabilities of overall survival (OS), disease-free survival (DFS), and transplant-related mortality (TRM) were 22 +/- 4%, 20 +/- 4%, 45 +/- 6%, respectively. In multivariate analysis, we demonstrated the favorable impact on OS, DFS and TRM of two factors over which we have no control (age <15 years, complete remission achievement) and three factors over which we have some control (female donor, acute and chronic graft-versus-host disease). The results of this study suggest that the graft-versus-leukemia effect is important in advanced AML and that new HSCT modalities are needed for some patients with this indication.

Adult acute leukemia

Untreated acute leukemia is a uniformly fatal disease with a median survival time shorter than 3 months. Current treatment strategies provide a significant increase in survival time for most patients, some of whom may be cured. The majority of patients with acute leukemia, however, ultimately die of the disease or complications of treatment. The effective treatment of acute leukemia requires (1) differentiation of acute myeloid leukemia (AML) from acute lymphoblastic leukemia (ALL) and recognition of clinically relevant subtypes; (2) identification of patients who are more likely or less likely than average to benefit from a conventional treatment; and (3) selection of therapy that provides a reasonable likelihood of response with acceptable risk of toxic effects. The diagnosis of acute leukemia is established in most cases by a bone marrow aspirate that demonstrates at least 30% blast cells. The traditional criteria to distinguish between AML and ALL rely on morphology and cytochemical reactions. Immunologic analysis of antigen expression and analysis for numerical or structural chromosomal abnormalities of leukemia cells are routinely feasible. Karyotypic analysis is of prognostic importance and should be performed on all diagnostic specimens of bone marrow aspirate. Immunophenotypic analysis may be useful to confirm the disease classification in selected cases. The importance of the routine immunophenotypic characterization of acute leukemia, however, is controversial. The subtypes that must be recognized because of the need for specific treatment include (a) acute promyelocytic leukemia (APL), which is the M3 subtype of AML, and (b) the L3 subtype or mature B-cell ALL. Induction therapy for acute leukemia is treatment intended to achieve induction of complete remission (CR). Complete remission is defined as the absence of morphologic evidence of leukemia after recovery of the peripheral blood cell counts. Failure to achieve CR may be attributed to death during chemotherapy-induced bone marrow hypoplasia or to drug resistance manifested either as failure to achieve hypoplasia or as persistent leukemia after recovery from hypoplasia. Postremission therapy is treatment administered in CR to prevent or delay relapse of the leukemia. However, the majority of patients have disease relapse. Intensification of therapy is a treatment strategy designed to overcome resistance to chemotherapy. Recent clinical trials of intensified induction or postremission therapy suggest improved outcome. However, the toxic effects of dose intensification can be substantial, limiting any potential benefit of this approach. Identification of prognostic factors may allow one to estimate the likelihood of an outcome, to determine an optimal treatment strategy. It is well established that age at the time of diagnosis, leukemia cell karyotype, and whether the leukemia is de novo or secondary are factors that influence treatment decisions. Patients with favorable prognostic factors should probably receive conventional therapy. Patients with unfavorable prognostic factors have shown little benefit from conventional therapy. In addition, factors that indicate poor outcome with conventional therapy are also predictive of poor outcome with intensified therapy. Consequently, these patients should be considered for investigational therapeutic strategies. The bias may be to counsel them to accept the potential increased morbidity of such treatment before there is definite evidence of the possibility of improved outcome. Induction chemotherapy for younger patients with AML (less than 55 years of age) in general consists of one or more courses of cytarabine (ara-C) and an anthracycline or an anthracycline derivative. Randomized trials have failed to confirm that treatment with either etoposide or high-dose ara-C induces disease remission. Patients with secondary AML, high levels of CD34 antigen expression, or an unfavorable karyotype, however, may benefit from ind

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.

Benefit of high-dose cytarabine-based consolidation chemotherapy for adults with acute myelogenous leukemia

Despite consolidation and/or maintenance chemotherapy most patients with newly diagnosed acute myelogenous leukemia relapse such that only 20-30% survive free of recurrence at five years. To evaluate the long-term effects of dose-intensive consolidation, we analysed 123 consecutive patients, age 16 to 84 (median 48 years), who received high-dose cytarabine-based consolidation chemotherapy. After a median follow-up of 88 months (range 26 to 126 months), 38 patients remain alive, with 26 in continued remission from 45 to 126+ months. Median remission duration for all eligible patients is 14 months (range 1.3 to 126 months) and actuarial leukemia-free survival at five years is 24 +/- 8%. Median survival from remission is 24 months (range 1.3 to 126 months) and actuarial survival from remission is 31 +/- 9%. Eighty-two patients (67%) have relapsed with an actuarial risk of relapse of 71 +/- 9% at five years. Adverse prognostic factors were age over 45 and male gender. When compared to historical controls (P = 0.02), dose-intensive consolidation produced improved leukemia-free survival for patients age < 45, but compliance and enhanced toxicity in the older age groups may limit further dose intensification.

Results of conventional-dose cytosine arabinoside and idarubicin in elderly patients with acute myeloid leukemia

Conventional-dose Ara-C (200 mg/m2 d 1-5) combined with idarubicin (12 mg/m2 d 1-3) was employed as remission induction and consolidation therapy in 23 elderly AML patients with a median age of 66 years (range, 60-75) with AML according to the FAB criteria (M1 n = 3, M2 n = 10, M4 n = 6, M5 n = 2, M6 n = 2), eligible for the study. In seven patients earlier MDS had been documented by previous bone marrow aspirates. The CR rate after one induction course was 65% (15/23). Toxicity was acceptable, with four patients dying during the chemotherapy-induced hypoplasia (4/23). Although 80% of the CR patients received two additional cycles of Ara-C and idarubicin as consolidation therapy, only two patients are still in continuous complete remission more than 12 months after achieving CR. The median disease-free survival of the CR patients was 11.5 months and the median survival of the entire group was 10 months. We conclude that conventional dose Ara-C/idarubicin is an effective protocol for inducing complete remission in elderly patients with AML, but that consolidation therapy consisting of two courses of the same regimen does not produce a relevant rate of long-term disease-free survival.

Effect of induction cytarabine dose intensity on long-term survival in acute myelogenous leukemia: results of a randomized, controlled study

The optimal dose and schedule of cytarabine in induction chemotherapy of newly diagnosed acute myelogenous leukemia is not established. We compared the use of cytarabine 200 mg/m2/day by continuous infusion for seven days to an intermediate-dose of cytarabine, 500 mg/m2 every 12 hours for 12 doses. Thirty-seven of 52 patients assigned to conventional-dose cytarabine achieved complete remission (71%) and the actuarial disease-free and overall survival after achieving remission were 22 +/- 16% and 31 +/- 19% respectively. Thirty-seven of 50 patients assigned to intermediate-dose cytarabine achieved remission (74%) and the actuarial disease-free and overall survival after achieving remission were 26 +/- 16% and 39 +/- 18% respectively. There were no statistically significant differences in complete remission rate, actuarial leukemia-free survival or overall survival between the groups. The most significant predictor for survival was age. Actuarial two year leukemia-free survival and overall survival for patients age > 60 were 8 +/- 15% and 20 +/- 19% respectively compared to 36 +/- 14% and 54 +/- 15% for patients age < or = 60 (P = .058 and .01, respectively). Induction regimen did not significantly affect disease free or overall survival for patients under or over age 60. We conclude that intermediate-dose cytarabine did not substantially improve results of induction for newly diagnosed acute myeloid leukemia.