Idarubicin in combination with etoposide and cytarabine in adult untreated acute non lymphoblastic leukemia

The effects of idarubicin versus other anthracyclines for induction therapy of patients with newly diagnosed leukaemia

BACKGROUND

Anthracycline combined with cytarabine has been the standard for induction therapy of newly diagnosed acute myeloid leukaemia (AML) for several decades. Due to theoretical advantages, idarubicin (IDA) might be the most effective and tolerable anthracycline. However, there is no evidence that would definitively prove the superiority of IDA over other anthracyclines.

OBJECTIVES

To assess the efficacy and safety of IDA versus other anthracyclines in induction therapy of newly diagnosed AML.

SEARCH METHODS

We identified relevant randomised controlled trials (RCTs) by searching the Cochrane Central Register of Controlled Trials (The Cochrane Library 2014, Issue 8), MEDLINE (from 1946 to 3 August 2014), EMBASE (from 1974 to 3 August 2014), Chinese BioMedical Literature Database (1978 to 3 August 2014), relevant conference proceedings and databases of ongoing trials.

SELECTION CRITERIA

RCTs that compared IDA with other anthracyclines in induction therapy of newly diagnosed AML.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the quality of studies according to methodological standards of the Cochrane Collaboration. We estimated hazard ratios (HRs) for time-to-event data outcomes using the inverse variance method, and risk ratios (RRs) for dichotomous data outcomes using the Mantel-Haenszel method. We adopted a fixed-effect model and repeated the main meta-analysis by a random-effects model in a sensitivity analysis.

MAIN RESULTS

We identified 2017 references. Ultimately, 27 RCTs (including 22 two-armed RCTs and five three-armed RCTs) involving 9549 patients were eligible. The consolidation treatments adopted in the studies were comparable and had no impact on the results. Overall, the risk of bias of the studies was unclear to high.Eighteen RCTs (N = 6755) assessed IDA versus daunorubicin (DNR). The main meta-analyses showed that IDA compared with DNR prolonged overall survival (OS) (12 studies, 5976 patients; HR 0.90, 95% confidence interval (CI) 0.84 to 0.96, P = 0.0008; high quality of evidence) and disease-free survival (DFS) (eight studies, 3070 patients; HR 0.88, 95% CI 0.81 to 0.96, P = 0.004; moderate quality of evidence), increased complete remission (CR) rate (18 studies, 6692 patients; RR 1.04, 95% CI 1.01 to 1.07, P = 0.009; moderate quality of evidence), and reduced relapse rate (four studies, 1091 patients; RR 0.88, 95% CI 0.80 to 0.98, P = 0.02; moderate quality of evidence), although increased the risks of death on induction therapy (14 studies, 6349 patients; RR 1.18, 95% CI 1.01 to 1.36, P = 0.03; moderate quality of evidence) and grade 3/4 mucositis (five studies, 2000 patients; RR 1.22, 95% CI 1.04 to 1.44, P = 0.02; moderate quality of evidence). There was no evidence for difference in the risks of grade 3/4 cardiac toxicity (six studies, 2795 patients; RR 0.98, 95% CI 0.70 to 1.37, P = 0.91; moderate quality of evidence) and other grade 3/4 adverse events (AEs). None of the studies reported on quality of life (QoL).Eight RCTs (N = 2419) evaluated IDA versus mitoxantrone (MIT). The main meta-analyses showed that there was no evidence for difference between arms in OS (six studies, 2171 patients; HR 0.98, 95% CI 0.89 to 1.08, P = 0.69; high quality of evidence), DFS (four studies, 249 patients; HR 0.88, 95% CI 0.70 to 1.10, P = 0.26; low quality of evidence), CR rate (eight studies, 2411 patients; RR 0.97, 95% CI 0.92 to 1.03, P = 0.32;moderate quality of evidence), the risks of death on induction therapy (five studies, 2055 patients; RR 1.10, 95% CI 0.88 to 1.38, P = 0.39; moderate quality of evidence) and relapse (three studies, 328 patients; RR 0.99, 95% CI 0.80 to 1.22, P = 0.89; moderate quality of evidence). There was no evidence for difference in the risks of grade 3/4 cardiac toxicity (one study, 160 patients; RR 0.67, 95% CI 0.11 to 3.88, P = 0.65; low quality of evidence) and other grade 3/4 AEs. None of the studies reported on QoL.Two RCTs (N = 211) compared IDA with doxorubicin (DOX). Neither study assessed OS. One study showed that there was no evidence for difference in DFS (63 patients; HR 0.62, 95% CI 0.34 to 1.14, P = 0.12; low quality of evidence). The main meta-analysis for CR rate showed an improved CR rate with IDA (two studies, 187 patients; RR 1.28, 95% CI 1.03 to 1.59, P = 0.02; low quality of evidence). Neither study provided data for the risks of death on induction therapy and relapse. One trial showed that there was no evidence for difference in the risk of grade 3/4 cardiac toxicity (one study, 100 patients; RR 0.31, 95% CI 0.01 to 7.39, P = 0.47; very low quality of evidence). Neither study reported on QoL.Two RCTs (N = 1037) evaluated IDA versus zorubicin (ZRB). Neither study assessed OS. One trial showed that there was no evidence for difference in DFS (one study, 155 patients; HR 1.25, 95% CI 0.83 to 1.88, P = 0.29; low quality of evidence). The main meta-analyses for CR and death on induction therapy both showed that there was no evidence for difference (CR rate: two studies, 964 patients; RR 1.04, 95% CI 0.96 to 1.13, P = 0.31; low quality of evidence. risk of death on induction therapy: two studies, 964 patients; RR 0.75, 95% CI 0.50 to 1.13, P = 0.17; moderate quality of evidence). Neither study reported the risks of relapse and grade 3/4 cardiotoxicity. One trial showed that IDA reduced the risk of grade 3/4 mucositis. Neither study reported on QoL.

AUTHORS' CONCLUSIONS

Compared with DNR in induction therapy of newly diagnosed AML, IDA prolongs OS and DFS, increases CR rate and reduces relapse rate, although increases the risks of death on induction therapy and grade 3/4 mucositis. The currently available evidence does not show any difference between IDA and MIT used in induction therapy of newly diagnosed AML. There is insufficient evidence regarding IDA versus DOX and IDA versus ZRB to make final conclusions. Additionally, there is no evidence for difference on the effect of IDA compared with DNR, MIT, DOX or ZRB on QoL.

Treatment and prognostic factors in acute myeloid leukaemia

Current induction chemotherapy regimens afford a complete remission in 60 to 80% of patients less than 60 years of age who are diagnosed with acute myelogenous leukaemia. Patients who undergo consolidation with high dose Ara-C or with autologous or allogeneic bone marrow transplantation can expect a long-term disease free survival of 30 to 45%. Which mode of consolidation is preferable is still being investigated in randomized studies. Many disease characteristics have been put forward as prognostic variables in treatment outcome and as understanding of the biology of AML has continued to expand, cytogenetic and molecular markers have assumed greater importance in disease characterization, but the ultimate role that these play in prognosis remains incompletely defined. Once AML has relapsed, bone marrow transplantation may result in prolonged disease free survival as compared to use of salvage chemotherapy regimens. Because the long-term survival of all patients diagnosed with AML is only in the order of 10 to 20%, new treatment approaches to this disease are required. Current clinical and research efforts have focused on modulation of the immune system, modulation of drug resistance phenotypes, and understanding of the response of leukaemic cells to haematopoietic growth factors.

Strategies in the treatment of acute myelogenous leukemia

The current treatment of acute myelogenous leukemia is far from satisfactory despite some recent advances. This review focuses on current strategies designed to improve treatment outcome. With advances in molecular biology, the definition of a complete remission should be redefined as a molecular remission where any abnormal gene rearrangement has disappeared or a clonal remission with morphologic characteristics of a complete remission, but with detectable genetics or molecular abnormalities. Abnormal gene rearrangements permit the detection of minimal residual disease, the significance of which remains to be determined. New drug development remains an important area of research and several new drugs are active in acute myelogenous leukemia. These include etoposide, idarubicin, mitoxantrone and carboplatin. Various combinations are undergoing clinical trials. Prognostic factors which predict for outcome include phenotyping, cytogenetics, cytokinetics, drug resistance and age. Proto-oncogene expression as a predictor of response is under investigation. Post-induction therapy remains controversial and approaches have included allogeneic bone marrow transplantation, autologous bone marrow transplantation with or without purging, intensive consolidation and maintenance programs. The superiority of one approach over the other has not been firmly established. Differentiating agents such as all-trans retinoic acid, and growth factors, the latter for supportive care, or recruitment of leukemic cells into the cycle are being investigated. Understanding the mechanisms of drug resistance should lead to the development of new approaches. Thus, with knowledge generated in many areas, the future should bring increasing success in treating AML.

Idarubicin: a second-generation anthracycline

Because of its in vitro activity in leukemic cell lines and Phase I studies of acute leukemia, Phase II and III clinical trials with idarubicin hydrochloride were conducted in patients with acute lymphocytic leukemia or acute nonlymphocytic leukemia. In the Phase III comparative trials between the combinations of idarubicin and cytarabine and daunorubicin hydrochloride and cytarabine, the idarubicin/cytarabine combination resulted in significantly greater complete remission rates and longer overall survival in two of three studies conducted in the US. As a result, the Food and Drug Administration approved intravenous idarubicin with a Class 1A rating in September 1990 for use in combination with other antileukemic drugs (e.g., cytarabine) for the treatment of acute myelogenous leukemia in adults. The recommended dose of idarubicin is 12 mg/m2 daily for three days by slow intravenous injection in combination with cytarabine. Although idarubicin causes myelosuppression similar to that described with daunorubicin, the incidence of cardiotoxicity in animal models is lower. Idarubicin also has the advantage of oral administration, but the oral formulation of the drug remains investigational. The use of idarubicin in pediatric patients also remains to be established.

Idarubicin (4-demethoxydaunorubicin) as single agent for remission induction of previously untreated acute promyelocytic leukemia: a pilot study of the Italian cooperative group GIMEMA

Because of the reported high sensitivity of acute promyelocytic leukemia to daunorubicin, we treated 27 consecutive, newly diagnosed, acute promyelocytic leukemia (APL) patients with the new anthracycline idarubicin (IDA) as induction therapy. IDA dosage ranged from 0.25 to 0.30 mg/kg/day and the drug was administered as single agent during a single induction course of 6 days. A total of 22/27 patients (81%) achieved complete remission, 4 (15%) died during induction and 1 patient was resistant to IDA. Extrahematological toxicity was acceptable. A total of 13/22 patients having achieved CR are still alive and in first CR after a median follow-up of 12 months. As for the treatment of the coagulopathy present in APL: 17/27 (63%) received tranexamic acid (6 g/daily) in continuous infusion for total of 7 d. None of the patients treated with tranexamic acid experienced thromboembolic complications. In conclusion, this multicentric pilot study confirms the antileukemic potency of IDA and the high sensitivity of APL to anthracycline derivatives.

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.

Idarubicin in combination with intermediate-dose cytarabine in the treatment of refractory or relapsed acute leukemias

13 patients with refractory or relapsed acute lymphoblastic leukemia (ALL) and 7 patients with acute myeloid leukemia (AML) were treated with a regimen that included idarubicin 12 mg/m2 intravenously daily for 3 d plus cytarabine 2 g/m2 by infusion over 3 hours daily for 3 d. There were 10 remissions (ALL:7; AML:3) in the 15 relapsed patients and 4 (ALL:3) in the 5 patients with primary refractory disease. Severe myelosuppression was observed in all patients. Toxicity of this regimen caused nausea and vomiting, stomatitis, infections and/or liver enzymes increase. Cardiac toxicity was not observed. 2 patients died in aplasia of Gram-negative septicemia and brain hemorrhage. In conclusion, the combination of idarubicin and intermediate-dose cytarabine (IDARA-C) seems to be highly effective and sufficiently well-tolerated for the treatment of refractory and relapsed acute leukemias.