Current controversies: which patients with acute myeloid leukaemia should receive a bone marrow transplantation?--a European view

Pediatric Acute Myeloid Leukemia—Past, Present, and Future

This review reports about the main steps of development in pediatric acute myeloid leukemia (AML) concerning diagnostics, treatment, risk groups, and outcomes. Finally, a short overview of present and future approaches is given.

The Role of Allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Leukemia

Allogeneic hematopoietic stem cell transplantation (HSCT) offers potentially curative treatment for many children with high-risk or relapsed acute leukemia (AL), thanks to the combination of intense preparative radio/chemotherapy and the graft-versus-leukemia (GvL) effect. Over the years, progress in high-resolution donor typing, choice of conditioning regimen, graft-versus-host disease (GvHD) prophylaxis and supportive care measures have continuously improved overall transplant outcome, and recent successes using alternative donors have extended the potential application of allotransplantation to most patients. In addition, the importance of minimal residual disease (MRD) before and after transplantation is being increasingly clarified and MRD-directed interventions may be employed to further ameliorate leukemia-free survival after allogeneic HSCT. These advances have occurred in parallel with continuous refinements in chemotherapy protocols and the development of targeted therapies, which may redefine the indications for HSCT in the coming years. This review discusses the role of HSCT in childhood AL by analysing transplant indications in both acute lymphoblastic and acute myeloid leukemia, together with current and most promising strategies to further improve transplant outcome, including optimization of conditioning regimen and MRD-directed interventions.

[Management of pediatric leukemia]

Acute leukemias are the most common pediatric cancer. With a cure rate of about 80%, their treatment is based on a combination of cytotoxic chemotherapies whose intensity is adapted to prognostic factors. Sometimes, allogeneic hematopoietic stem cell transplantation is indicated. New therapeutic options are being developed, such as CAR T-cells.

Cell therapies for hematological malignancies: don't forget non-gene-modified t cells!

Cell therapy currently performs an important role in the treatment of patients with various hematological malignancies. The response to the cell therapy is regulated by multiple factors including the patient's immune system status, genetic profile, stage at diagnosis, age, and underlying disease. Cell therapy that does not require genetic manipulation can be mediated by donor lymphocyte infusion strategies, selective depletion in the post-transplant setting and the ex vivo expansion of antigen-specific T cells. For hematologic malignancies, cell therapy is contributing to enhanced clinical responses and overall survival and the immune response to cell therapy is predictive of response in multiple cancer types. In this review we summarize the available T cell therapeutics that do not rely on gene engineering for the treatment of patients with blood cancers.

Outcomes of allogeneic stem cell transplantation among patients with acute myeloid leukemia presenting active disease: Experience of a single European Comprehensive Cancer Center

Introduction:

Allogeneic hematopoietic stem cell transplantation (ASCT) representes a potentially curative approach for patients with relapsed or refractory acute myeloid leukemia (AML). We report the outcome of relapsed/refractory AML patients treated with ASCT.

Method:

A retrospective cohort from 1994 to 2013 that included 61 patients with diagnosis of relapsed/refractory AML. Outcomes of interest were transplant-related mortality (TRM), incidence of acute and chronic graft-versus-host disease (GVHD), relapse incidence, progression-free survival (PFS) and overall survival (OS). Statistical significance was set at p<0.05.

Results:

The median age was 61 years (range 1 to 65). The cumulative incidence of 90 days, 1 year, and 3 years TRM were 60%, 26.7%, and 13.3%, respectively (p<0.001). The incidence of relapse was 21.7% at 1 year, 13% at 3 years, and 8.7% at 5 years. Median OS was estimated to be 8 months (95CI 3.266-12.734) and median PFS, 3 months (95CI 1.835-4.165).

Conclusion:

In our cohort, TRM in first years after ASCT remains considerable, but ASCT in this setting seems to be a good choice for AML patients with active disease. However, novel approaches are needed to reduce TRM and relapse in this set of patients.

Collaborative Efforts Driving Progress in Pediatric Acute Myeloid Leukemia

Diagnosis, treatment, response monitoring, and outcome of pediatric acute myeloid leukemia (AML) have made enormous progress during the past decades. Because AML is a rare type of childhood cancer, with an incidence of approximately seven occurrences per 1 million children annually, national and international collaborative efforts have evolved. This overview describes these efforts and includes a summary of the history and contributions of each of the main collaborative pediatric AML groups worldwide. The focus is on translational and clinical research, which includes past, current, and future clinical trials. Separate sections concern acute promyelocytic leukemia, myeloid leukemia of Down syndrome, and relapsed AML. A plethora of novel antileukemic agents that have emerged, including new classes of drugs, are summarized as well. Finally, an important aspect of the treatment of pediatric AML--supportive care--and late effects are discussed. The future is bright, with a wide range of emerging innovative therapies and with more and more international collaboration that ultimately aim to cure all children with AML, with fewer adverse effects and without late effects.

Overview of therapy and strategies for optimizing outcomes in de novo pediatric acute myeloid leukemia

Although acute myelogenous leukemia (AML) accounts for <20 % of leukemia in children, it is responsible for over half of all pediatric leukemia deaths. Improvement in event-free survival rates, now over 50 %, are due largely to intensification of chemotherapy, aggressive supportive care, development of risk stratification based on cytogenetic and molecular markers, and improved salvage regimens. Despite this improvement over the past few decades, the survival rates have recently plateaued, and further improvement will need to take into account advances in molecular characterization of AML, development of novel agents, and better understanding of host factors influencing toxicity and response to chemotherapy. This article reviews the epidemiology and biology trends in diagnosis and treatment of pediatric acute myelogenous leukemia.

Comparable survival for pediatric acute myeloid leukemia with poor-risk cytogenetics following chemotherapy, matched related donor, or unrelated donor transplantation

BACKGROUND

We sought to better define the role of hematopoietic cell transplantation (HCT) in first remission (CR1) for high-risk pediatric acute myeloid leukemia (AML).

PROCEDURES

Outcomes were compared among patients aged less than 21 years with cytogenetically defined poor-risk AML treated with chemotherapy, matched related (MRD), or unrelated donor (URD) transplantation in CR1. Poor-risk cytogenetics was defined as monosomy 7/del7q, monosomy 5/del 5q, abnormalities of 3q, t(6;9)(p23;q34), or complex karyotype. Included are patients treated on Children's Oncology Group trials or reported to the Center for International Blood and Marrow Transplant Research from 1989 to 2006.

RESULTS

Of the 233 patients, 123 received chemotherapy, 55 received MRD HCT, and 55 received URD HCT. The 5-year overall survival from the time of consolidation chemotherapy or transplant conditioning was similar: chemotherapy (43% ± 9%), MRD (46% ± 14%), or URD (50% ± 14%), P = 0.99. Similarly, multivariate analysis demonstrated no significant differences in survival [(reference group = chemotherapy); MRD HR 1.08, P = 0.76; URD HR 1.13, P = 0.67] despite lower relapse risk with URD HCT (HR = 0.43, P = 0.01).

CONCLUSIONS

Our findings do not provide support for the preferential use of HCT over chemotherapy alone for children with cytogenetically defined poor-risk AML in CR1.

Transplantation for children with acute myeloid leukemia: a comparison of outcomes with reduced intensity and myeloablative regimens

The safety and efficacy of reduced-intensity conditioning (RIC) regimens for the treatment of pediatric acute myeloid leukemia is unknown. We compared the outcome of allogeneic hematopoietic cell transplantation in children with acute myeloid leukemia using RIC regimens with those receiving myeloablative-conditioning (MAC) regimens. A total of 180 patients were evaluated (39 with RIC and 141 with MAC regimens). Results of univariate and multivariate analysis showed no significant differences in the rates of acute and chronic graft-versus-host disease, leukemia-free, and overall survival between treatment groups. The 5-year probabilities of overall survival with RIC and MAC regimens were 45% and 48%, respectively (P = .99). Moreover, relapse rates were not higher with RIC compared with MAC regimens (39% vs 39%; P = .95), and recipients of MAC regimens were not at higher risk for transplant-related mortality compared with recipients of RIC regimens (16% vs 16%; P = .73). After carefully controlled analyses, we found that in this relatively modest study population, the data supported a role for RIC regimens for acute myeloid leukemia in children undergoing allogeneic hematopoietic cell transplantation. The data also provided justification for designing a carefully controlled randomized clinical trial that examines the efficacy of regimen intensity in this population.

Non-TBI hematopoietic stem cell transplantation in pediatric AML patients: a single-center experience

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) has been established as a promising treatment in acute myeloid leukaemia (AML). Several studies have been performed to minimize the toxicity of HSCT in children without impairing the efficacy. We report our long-term results of HSCT in pediatric AML patients using non-total body irradiation conditioning regimen.

PROCEDURE

From May 1991 to June 2010, 133 pediatric patients with AML (age<15 y) who were referred to our institute underwent autologous (auto-) or allogeneic (allo-) HSCT. The conditioning regimen consisted of oral busulfan plus etoposide in auto-HSCT patients and oral busulfan plus cyclophosphamide in allo-HSCT patients.

RESULTS

Overall survival (OS), leukemia-free survival (LFS), probability of relapse, and transplantation-related mortality at 3 years were 67.6%, 62.2.5%, 27.3%, and 10.1%, respectively. There was no significant difference between allo-HSCT and auto-HSCT groups. In multivariable analysis using Cox proportional hazards regression model, male sex was associated with significantly improved OS (P<0.001) and LFS (P=0.022). An age ≤3 years was associated with higher relapse (P=0.034) and worse OS (P=0.001) and LFS (P=0.014).

CONCLUSIONS

The role of allo-HSCT in pediatric AML patients in first complete remission is uncertain. Further randomized studies are recommended to clarify the optimal postremission therapy in these patients.

Leukemia and lymphoma

Leukemia and lymphoma are the most common and third most common pediatric malignancies, respectively, and share cell lineages, but the clinical and imaging manifestations of these malignancies vary substantially. Along with providing pertinent details on classification, epidemiology, and treatment, this article reviews the current roles of imaging in the management of childhood leukemia and lymphoma, with attention to diagnosis, staging, risk stratification, therapy response assessment, and surveillance for disease relapse and adverse effects of therapy. Advances in functional imaging are also discussed to provide insights into future applications of imaging in the management of pediatric patients with leukemia and lymphoma.

Improved survival outcome of childhood acute myeloid leukemia with intensified chemotherapy in Chinese children

With the use of intensive chemotherapy and hematopoietic stem cell transplantation (HSCT), the prognosis of childhood acute myeloid leukemia (AML) improved over the last 2 decades. Survival data of Chinese pediatric patients were seldom reported. The authors adopted modified UK Medical Research Council (MRC) AML protocols for treatment of childhood AML since 1994. From 1994 to 2008, the outcomes of Chinese AML patients were studied. Sixty-eight patients were studied. The median age at diagnosis was 9.9 years. Twenty-five patients (36.8%) had favorable cytogenetic karyotypes, including t(15;17), t(8;21) and inv(16). Complete remission (CR) rate was 91.2%. The relapse rate was 29.4%. For non-M3 patients, the 5-year overall survival (pOS) was 64% ± 7% and event-free survival (pEFS) was 53% ± 7%. For those non-good-risk patients who achieved CR, there were no significant differences in outcomes between patients who received HSCT in CR1 and those received chemotherapy alone (5-year pOS 80% ± 13% and 69% ± 9%, P = .52), 5-year pEFS 69% ± 15% and 55% ± 10%, P = .40). The pOS of the 20 relapsed patients was 29% ± 11%. Sixteen patients with t(8;21) and inv(16) had similar outcome with those without favorable cytogenetics (pOS 66% ± 12% versus 65% ± 7%, P = .39; pEFS 60% ± 11% versus 54% ± 8%, P = .45). Patients who achieved CR after 2 or more courses of chemotherapy and presenting white blood cell count (WBC) ≥ 100 × 10(9)/L had poorer outcome (pOS 40% versus 80%P < .01; 43% versus 70%, P = .02, respectively). Intensified chemotherapy improved outcome of Chinese AML children. CR after first course of chemotherapy and WBC at diagnosis were important prognostic factors.

The presence of central nervous system disease at diagnosis in pediatric acute myeloid leukemia does not affect survival: a Children's Oncology Group study

BACKGROUND

The presence of central nervous system (CNS) disease in pediatric acute myeloid leukemia (AML) is often thought to confer a worse prognosis. This study examined the outcome of children with AML who had CNS disease at diagnosis.

METHODS

Patients enrolled on Children's Cancer Group protocols 2861, 2891, 2941, and 2961 being treated for de novo AML were classified for the presence of CNS disease at diagnosis as CNS1 (<5 WBC in the CSF without blasts), CNS2 (<5 WBC in the CSF with blasts), or CNS3 (> or =5 WBC in the CSF with blasts). CNS disease at diagnosis was then analyzed regarding patient characteristics and outcome.

RESULTS

There was an incidence of CNS disease (i.e., CNS3 status) of 11% in the 1,459 patients analyzed in this study. The risk factors found are young age, high white cell count, hepatomegaly or splenomegaly at diagnosis, M4 subtype, chromosome 16 abnormalities, and hyperdiploid cytogenetics. There were no significant differences in overall survival, event free survival, or remission rates between the groups; however, a significant difference was seen between the CNS1 and CNS3 groups in disease free survival and isolated CNS relapse risk.

CONCLUSIONS

Patients with CNS disease at diagnosis have similar survival to those without CNS disease, although they have an increased incidence of isolated CNS relapse. Patients with CNS disease at diagnosis may warrant more aggressive CNS directed therapy.

A review on allogeneic stem cell transplantation for newly diagnosed pediatric acute myeloid leukemia

Survival of pediatric acute myeloid leukemia (AML) has improved considerably over the past decades. Since 1985, allogeneic stem cell transplantation (allo-SCT) is widely recommended for patients who have a matched sibling donor. However, it remains controversial whether allo-SCT is superior to chemotherapy for children with newly diagnosed AML. This review summarizes phase 3 clinical trials that compared allo-SCT with chemotherapy (including autologous SCT) in pediatric AML, excluding studies that did not use the intention-to-treat analysis or correct for time-to-transplantation. Although allo-SCT might prevent more relapses than chemotherapy, the number needed for transplantation (with allo-SCT) to prevent one relapse is in the order of 10 patients. Moreover, overall survival is similar with both methods in most recent studies, apparently because of increased salvagability of a relapse when initial therapy concerned chemotherapy only, and because of a higher treatment-related mortality with allo-SCT. Because allo-SCT also gives more severe side effects and results more often in secondary malignancies than chemotherapy, we do not recommend allo-SCT in first remission for pediatric AML in general. Further research should focus on the possibility that subgroups might benefit from allo-SCT, aiming at further improvements in the prognosis of pediatric AML.

Acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous group of leukemias that result from clonal transformation of hematopoietic precursors through the acquisition of chromosomal rearrangements and multiple gene mutations. As a result of highly collaborative clinical research by pediatric cooperative cancer groups worldwide, disease-free survival has improved significantly during the past 3 decades. Further improvements in outcomes of children who have AML probably will reflect continued progress in understanding the biology of AML and the concomitant development of new molecularly targeted agents for use in combination with conventional chemotherapy drugs.

Hematopoietic stem cell transplantation for leukemia

Leukemia represents the most common pediatric malignancy, accounting for approximately 30% of all cancers in children less than 20 years of age. Most children diagnosed with leukemia are cured without hematopoietic stem cell transplantation (HSCT), but for some high-risk subgroups, allogeneic HSCT plays an important role in their therapeutic approach. The characteristics of these high-risk subgroups and the role of HSCT in childhood leukemias are discussed.

Risk-stratified therapy and the intensive use of cytarabine improves the outcome in childhood acute myeloid leukemia: the AML99 trial from the Japanese Childhood AML Cooperative Study Group

PURPOSE

To improve the prognosis in children with newly diagnosed acute myeloid leukemia (AML) by introducing a dose-dense intensive chemotherapy regimen and an appropriate risk stratification system.

PATIENTS AND METHODS

Two hundred forty children with de novo AML were treated with continuous cytarabine-based induction therapy and stratified to three risk groups based on the initial treatment response, age, and WBC at diagnosis and cytogenetics. All of the patients were treated with intensive consolidation chemotherapy including three or four courses of high-dose cytarabine. Allogeneic hematopoietic stem-cell transplantation (HSCT) was indicated for only the intermediate-risk patients with matched related donors and for all the high-risk subsets.

RESULTS

Two hundred twenty-seven children (94.6%) achieved a complete remission (CR). Four children demonstrated induction death. The median follow-up of the live patients was 55 months (range, 37 to 73 months). The 5-year overall survival of all 240 children was 75.6% (95% CI, 70.3% to 81.4%) and event-free survival was 61.6% (95% CI, 55.8% to 68.1%). The 5-year disease-free survival in each risk group were 71.3% (95% CI, 63.4% to 80.2%) in the low-risk group (n = 112), 59.8% (95% CI, 50.6% to 70.7%) in the intermediate-risk group (n = 92), and 56.5% (95% CI, 39.5% to 80.9%) in the high-risk group (n = 23). Eight children died during the first CR, including four after HSCT.

CONCLUSION

A high survival rate, 75.6% at 5 years, was achieved for childhood with de novo AML in the AML99 trial. The treatment strategy was well tolerated with only 1.7% induction death rate and 3.5% remission death rate. Low-risk children were successfully treated with chemotherapy alone.

Impact of disease risk on efficacy of matched related bone marrow transplantation for pediatric acute myeloid leukemia: the Children's Oncology Group

PURPOSE

There is considerable variation in the use of HLA-matched related bone marrow transplantation (BMT) for the treatment of pediatric patients with newly diagnosed acute myeloid leukemia (AML). Some oncologists have argued that BMT should be offered to most patients in first complete remission (CR). Others have maintained that transplantation in first remission should be reserved for patients with high-risk disease. We performed this study to determine how disease risk influences the efficacy of BMT.

METHODS

We combined data from four cooperative group clinical trials: Pediatric Oncology Group 8821, Children's Cancer Group (CCG) 2891, CCG 2961, and Medical Research Council 10. Using cytogenetics and the percentage of marrow blasts after the first course of chemotherapy, patients were stratified into favorable, intermediate, and poor-risk disease groups. Patients who could not be risk classified were analyzed separately. Outcomes for patients assigned to BMT and for patients assigned to chemotherapy alone were compared.

RESULTS

The data set included 1,373 pediatric patients with AML in first CR. In the intermediate-risk group, the estimated disease-free survival at 8 years for patients who did not undergo transplantation was 39% +/- 5% (2 SE), whereas it was 58% +/- 7% for BMT patients. The estimated overall survival for patients who did not undergo transplantation was 51% +/- 5%, whereas it was 62% +/- 7% for BMT patients. Both differences were significant (P < .01). There were no significant differences for survival in the other two risk groups or in the non-risk-stratified patients.

CONCLUSION

Our study indicates that HLA-matched related BMT is an effective treatment for pediatric patients with intermediate-risk AML in first CR.

Individual physician practice variation in hematopoietic cell transplantation

PURPOSE

Previous studies have evaluated practice variation in hematopoietic cell transplantation (HCT) among transplant centers and countries. There are no studies investigating individual physician practice variation in HCT.

METHODS

An international Internet-based survey of transplant physicians collected data on medical decisions made by adult and pediatric HCT physicians. Multivariable analyses identified practitioner and transplant center characteristics predictive of medical decision making.

RESULTS

Analysis of 526 assessable respondents showed a wide variation in management approaches to specific clinical scenarios. Pediatric and adult transplant physicians differed significantly in their management strategies for chronic myeloid leukemia, acute and chronic graft-versus-host disease, and choice of graft source for patients with aplastic anemia. Among adult transplant physicians, there was little agreement on the patient factors favoring reduced intensity conditioning or myeloablative conditioning.

CONCLUSION

These results emphasize the heterogeneity of worldwide transplant practices. Local preferences or biases likely result in similar patients being offered different transplant and treatment procedures. The degree of practice variation also highlights the need for clinical trials to clarify areas of controversy. Where clinical trials are not feasible, data from observational studies may be the best available evidence to guide practice.

Indications and donor selections for allogeneic stem cell transplantation in children with hematologic malignancies

Allogeneic stem cell transplantation (SCT) is the only curative approach for many patients with advanced or high-risk leukemia. Advances in supportive care and management of graft-versus-host disease have resulted in improvements in outcomes of related and unrelated donor SCT, creating controversies as to which strategy might be the optimal therapy for individual patients. This article discusses the indications and donor selection strategies for SCT in patients with malignant hematologic disease.

Acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous group of leukemias that result from clonal transformation of hematopoietic precursors through the acquisition of chromosomal rearrangements and multiple gene mutations. As a result of highly collaborative clinical research by pediatric cooperative cancer groups worldwide, disease-free survival has improved significantly during the past 3 decades. Further improvements in outcomes of children who have AML probably will reflect continued progress in understanding the biology of AML and the concomitant development of new molecularly targeted agents for use in combination with conventional chemotherapy drugs.

Toxicity and outcome of children with treatment related acute myeloid leukemia

BACKGROUND

The aim of this study was to evaluate the clinical course and outcome of children with treatment related acute myeloid leukemia (tAML) and compare them to children with primary AML (pAML).

PROCEDURE

We retrospectively reviewed the demographic, treatment, toxicity, and outcome data of children with tAML and treatment related myelodysplastic syndrome (tMDS), treated at our institution between 1975 and 2005. We compared these parameters with matched controlled children with pAML. Finally we compared overall survival (OS) for tAML with all pAML children treated at the study era in our institution.

RESULTS

Twenty-one patients with tAML (n = 19) and tMDS (n = 2) were identified. Three years event-free survival (EFS) and OS were both 14 +/- 8%. Compared to pAML patients, tAML had a higher rate of adverse cytogenetics (P < 0.008) and inferior OS (P = 0.027) but no significant difference in treatment toxicity or death. All survivors were treated with allogeneic hematopoietic stem cell transplantation (HSCT).

CONCLUSIONS

In this population based report of pediatric tAML, outcome was poor and was related to a higher probability of poor cytogenetic features rather than excessive toxicities or inability to deliver therapy. HSCT should be considered for patients with tAML. These preliminary findings should set the stage for prospective cooperative studies.

Prognostic factors and risk-based therapy in pediatric acute myeloid leukemia

Acute myeloid leukemia (AML) has posed significant therapeutic challenges to pediatric oncologists. Despite intensive therapy, half of the children with AML relapse and die from their disease. Efforts to identify risk factors in AML are directed toward defining populations who may benefit from alternative therapies. Patients at lower risk for relapse may benefit from treatment de-escalation, sparing them adverse side effects. Management of high-risk patients may prove more difficult, as the nearly myeloablative nature of AML therapy leaves little room for therapy escalation short of stem cell transplantation. This review evaluates prognostic factors in pediatric AML and discusses the feasibility of using these factors in risk-adapted therapy regimens.

Treatment strategies and long-term results in paediatric patients treated in four consecutive AML-BFM trials

A total of 1111 children with acute myeloblastic leukaemia (AML) were treated in four consecutive Berlin-Frankfurt-Münster (BFM) studies from 1978 to 1998. The first cooperative trial AML-BFM 78 established intensive chemotherapy with seven drugs, CNS irradiation and 2-year maintenance, achieving a long-term survival (overall survival (OS)) of 40%. Induction intensification in AML-BFM 83 resulted in significant improvement of disease-free survival (DFS). The risk of haemorrhage, especially in children with hyperleukocytosis, proved the high relevance of supportive care. In AML-BFM 87, the benefit of CNS irradiation in preventing CNS/systemic relapses was demonstrated. In AML-BFM 93, the introduction of idarubicin during first induction followed by intensification with HAM increased the 5-year EFS, DFS and OS to 50+/-2, 61+/-3 and 57+/-2%, respectively. Stem cell transplantation (SCT), as applied in high-risk patients with a matched related donor, did not significantly improve the outcome compared to chemotherapy alone. In spite of treatment intensification, the therapy-related death rate decreased from trial to trial, mainly during induction. The future aim is to reduce long-term sequelae, especially cardiotoxicity, by administration of less cardiotoxic drugs, and toxicity of SCT by risk-adapted indications. The AML-BFM studies performed in three European countries with >70 cooperating centres have significantly improved the outcome in AML children; nevertheless, increasing experience with these intensive treatment regimens is of fundamental importance to reduce fatal complications.

Treatment strategy and results in children treated on three Dutch Childhood Oncology Group acute myeloid leukemia trials

This report describes the long-term follow-up data of three consecutive Dutch Childhood Oncology Group acute myeloid leukemia (AML) protocols. A total of 303 children were diagnosed with AML, of whom 209 were eligible for this report. The first study was the AML-82 protocol. Results were inferior (5-year probability of overall survival (pOS) 31%) to other available regimes. Study AML-87 was based on the BFM-87 protocol, with prophylactic cranial irradiation in high-risk patients only, and without maintenance therapy. This led to a higher cumulative incidence of relapse than that reported by the Berlin-Frankfurt-Münster (BFM), but survival was similar (5-year pOS 47%), suggesting successful retrieval at relapse. The subsequent study AML-92/94 consisted of a modified BFM-93 protocol, that is, without maintenance therapy and prophylactic cranial irradiation. However, all patients were to be transplanted (auto- or allogeneic), although compliance was poor. Antileukemic efficacy was offset by an increase in the cumulative incidence of nonrelapse mortality, especially in remission patients, and survival did not improve (5-year pOS 44%). Our results demonstrate that outcome in childhood AML is still unsatisfactory, and that further intensification of therapy carries the risk of enhanced toxicity. Our patients are currently included in the MRC AML studies, based on the results of their AML 10 trial.

Allogeneic versus autologous versus peripheral stem cell transplantation in CR1 pediatric AML patients: a single center experience

BACKGROUND

Treatment of childhood acute myelocytic leukemia (AML) in first remission, is still evolving. Allogeneic bone marrow transplantation (BMT) in patients with a donor has been well established, but the role of autologous transplantation remains of interest, particularly in the light of some encouraging results in adults.

PROCEDURE

Out of 81 pediatric patients with AML in first CR, 67 were biologically randomized for allogeneic (n = 31), autologous (n = 20), or peripheral stem cell transplant (n = 16) after completing consolidation treatment, with the remaining (n = 11) dropping out or receiving chemotherapy. Disease free survival (DFS) of these different groups were analyzed.

RESULTS

Allogeneic transplantation is not superior to autologous and autologous peripheral blood stem cell transplantation (PBSCT) (DFS in 5 years is 61%, 50%, and 75%). The 5 years DFS in the autologous PBSCT group is significantly better than in the autologous BMT group (75% vs. 50%, P < 0.05).

CONCLUSION

In pediatric AML patients without a donor, autologous BMT or autologous PBSCT appears to be an effective treatment option with low transplant related mortality especially in less privileged countries where the chemotherapy only results are still low.

Postremission therapy for children with acute myeloid leukemia: the children's cancer group experience in the transplant era

We reviewed consolidation therapy results and analyzed postremission outcomes for 1464 children less than 21 years old at diagnosis in five consecutive Children's Cancer Group acute myeloid leukemia trials between 1979 and 1996. Children in remission were allocated to allogeneic bone marrow transplantation (BMT) (N=373) in first remission, if a matched family donor was available. Remaining children were assigned consolidation chemotherapy (N=688) or autologous purged BMT (N=217), or withdrew from study before assignment, or with unknown data (N=186). Overall and disease-free survival were superior for children assigned allogeneic transplants. High (>50,000/microl) diagnostic white blood cell (WBC) count was prognostic for inferior outcome, but French-American-British (FAB) subtypes were not. Inv(16) is a favorable karyotypic feature for children in first remission and t(8;21) is not. Allogeneic transplantation benefit was evident in most children, including those with high or low diagnostic WBC count, each FAB subtype, and t(8;21), but was not seen in children with inv(16). Therefore, these data suggest reserving matched related donor allogeneic transplantation for children with inv(16) for second remission, but not those with t(8;21).

Impact of the cyclooxygenase system on doxorubicin-induced functional multidrug resistance 1 overexpression and doxorubicin sensitivity in acute myeloid leukemic HL-60 cells

Multidrug resistance (MDR), a challenge in treating childhood acute myeloid leukemia (AML), is frequently associated with decreased drug accumulation caused by multidrug transporter MDR1. Doxorubicin, an important anti-AML drug, is a known MDR1 substrate and inducer. Its cytostatic efficacy is thus limited by MDR1 overexpression. A recent study demonstrated cyclooxygenase-2-dependent, prostaglandin E(2) (PGE(2))-mediated regulation of mdr1b expression in primary rat hepatocyte cultures. Cyclooxygenase-2 expression is increased in several malignancies and considered a negative prognostic factor. Our study focused on cyclooxygenase system's impact on drug-induced MDR1 overexpression in AML cells. As a prerequisite, coexpression of MDR1 and cyclooxygenase-2 mRNA in HL-60 cells and primary AML blasts was demonstrated by Northern blot. Interestingly, incubation of AML cells with doxorubicin not only induced functionally active MDR1 overexpression but also mediated increased cyclooxygenase-2 mRNA and protein expressions with subsequent PGE(2) release (determined by flow cytometry, rhodamine123 efflux assay, reverse transcription-polymerase chain reaction, and enzyme-linked immunosorbent assay). After preincubation and subsequent parallel treatment with the cyclooxygenase-2-preferential inhibitor meloxicam, doxorubicin-induced MDR1 overexpression and function were reduced (maximally at 0.1-0.5 microM meloxicam), whereas cytostatic efficacy of doxorubicin in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assays was significantly increased by up to 78 (HL-60) and 30% (AML blasts) after 72 h of doxorubicin treatment. In HL-60 cells, meloxicam-dependent effect on doxorubicin cytotoxicity was neutralized by PGE(2) preincubation. In conclusion, the cyclooxygenase system, especially the cyclooxygenase-2 isoform, might be involved in regulating doxorubicin-induced MDR1 overexpression in AML cells, with PGE(2) seeming to be a mediating factor. Cyclooxygenase inhibitors thus bear promise to overcome MDR in AML and improve therapy.

Possibilities for tailored and targeted therapy in paediatric acute myeloid leukaemia

The clinical outcome of acute myeloid leukaemia (AML) in children has improved considerably using intensive chemotherapy and/or stem cell transplantation. This leads to cure in 50-70% of patients, and also results in significant morbidity and mortality. Hence, we need other ways to improve the cure rate. This review discusses possibilities for tailored therapy, reviewing in vitro cellular drug sensitivity data. The results provide suggestions regarding the adaptation of clinical protocols in certain AML subgroups, although further clinical studies will show whether this is effective. Secondly, we review type 1 genetic abnormalities (such as receptor tyrosine kinase mutations) that result in enhanced survival and proliferation of leukaemic cells, which can be detected in approximately 50% of paediatric AML samples, and are non-randomly associated with French-American-British type and cytogenetic subgroups. FLT3 internal tandem duplication is associated with poor clinical outcome, and may be used for risk-group stratification. The first results with small molecule inhibitors in adult AML do not suggest their use in children as yet. International collaboration is needed to further improve outcome by developing treatment protocols for subgroups of paediatric AML.

Adult acute myeloid leukaemia

The curability of acute myeloid leukaemia (AML) in a fraction of adult patients was demonstrated a long time ago. Currently, the probability of cure is consistently above fifty per cent in patients with de novo disease expressing favourable-risk associated cytogenetic features. Even better, the cure rate exceeds 75% in the acute promyelocytic subtype since the introduction of retinoic acid-containing regimens. In the meantime, continuing progress in supportive care systems and stem cell transplant procedures is making myeloablative therapies, when needed, somewhat less toxic-and thereby more effective-than in the recent past. Therefore, evidence is accumulating to indicate an improved therapeutic trend over the years, with the notable exception of older (>55 years) patients with adverse-risk chromosomal aberrations and/or leukemia secondary to myelodysplasia or prior cancer-related chemotherapy and/or radiotherapy. This review conveys the many facets of this progress, focusing on diagnostic subsets, risk classes, newer biological issues and conventional as well as innovative therapeutic interventions with or without autologous/allogeneic stem cell transplantation.

Prognostic factors and risk-based therapy in pediatric acute myeloid leukemia

Acute myelocytic leukemia (AML) is a heterogeneous disease that accounts for nearly a quarter of the pediatric leukemias. Despite near myeloablative therapy, half of patients relapse and die from their disease. Identification of patients at high risk of relapse early in the course of treatment may allow for treatment modification to improve their outcome. In addition, patients at lower risk of relapse may benefit from treatment de-escalation, sparing them adverse side effects. This review describes prognostic factors that play a major role in the outcome of children with AML and their potential use for treatment stratification in pediatric AML trials.

Consolidation therapy with autologous bone marrow transplantation in adults with acute myeloid leukemia: a meta-analysis

BACKGROUND

The optimal consolidation therapy for adults who are in first remission of acute myeloid leukemia after induction chemotherapy and who do not have a histocompatible donor is poorly established. We conducted a meta-analysis to compare the efficacy of autologous bone marrow transplantation with that of non-myeloablative chemotherapy alone (or no further treatment).

METHODS

Eligible studies were identified by searching electronic databases and by examining the reference lists of relevant studies and review articles. Eligible studies were those that prospectively enrolled adults with acute myeloid leukemia and randomly assigned patients who were in first remission and who did not have a matched sibling donor to one of the two consolidation therapies. Two reviewers independently assessed all studies for relevance and validity. We used a fixed-effects model to calculate the ratio of probabilities for disease-free and overall survival at 48 months or at the nearest recorded assessment point for each study and for all studies combined. All statistical tests were two-sided.

RESULTS

We identified 587 potentially relevant studies, 36 of which were retrieved for detailed evaluation. In the six studies eligible for this meta-analysis, a total of 1044 patients were randomly assigned to receive autologous bone marrow transplantation or non-myeloablative chemotherapy (five studies) or autologous bone marrow transplantation or no further treatment (one study). Compared with patients who received chemotherapy or no further treatment, patients who received autologous bone marrow transplantation had a better disease-free survival (ratio of disease-free survival probabilities = 1.24, 95% confidence interval [CI] = 1.06 to 1.44; P =.006) but a similar overall survival (ratio of overall survival probabilities = 1.01, 95% CI = 0.89 to 1.15; P =.86).

CONCLUSION

Our results do not support the routine use of autologous bone marrow transplantation in adult acute myeloid leukemia patients in first remission.

Treatment stratification based on initial in vivo response in acute myeloid leukaemia in children without Down's syndrome: results of NOPHO-AML trials

Three consecutive protocols for childhood acute myeloid leukaemia (AML) have been used in the Nordic countries since 1984: the Nordic Society for Paediatric Haematology and Oncology (NOPHO)-AML84 was of moderate intensity, NOPHO-AML88 of high intensity with upfront loading and aggressive consolidation. NOPHO-AML93 utilized the same treatment blocks as NOPHO-AML88, but after the first block those children with a hypoplastic non-leukaemic bone marrow were allowed to recover from aplasia. Poor responders received intensified induction therapy. Between January 1993 and December 2000, 219 children without Down's syndrome were entered on NOPHO-AML93. Compared with NOPHO-AML88, the event-free survival (EFS) at 7 years increased from 41% to 49% (P = 0.06) and 7-year overall survival increased from 47% to 64% (P < 0.01). Toxic death during induction was reduced from 10% to 3%. Survival was similar in patients receiving stem cell transplantation or chemotherapy only in first remission. The major prognostic factors in NOPHO-AML93 were response to therapy and cytogenetics. A total of 67% of patients achieved remission after the first induction course and showed an EFS of 56% compared with 35% in those not in remission (P < 0.01). Cytogenetic results were obtained in 95% of patients. Patients with t(9;11) (p22;q23) (n = 16) experienced a significantly better EFS (86%) than other cytogenetic groups. The overall outcome was improved by employing the previous toxic protocol with different timings, and through individualizing therapy according to the initial response of the patient.

Hematopoietic stem cell transplantation for hematological malignancies in Europe

Hematopoietic stem cell transplants (HSCTs) are considered the best treatment option for many hematological malignancies, and transplant numbers have increased five-fold during the last decade. Only a few controlled prospective studies are available, and different opinions prevail. Data from 118 167 HSCT (36% allogeneic, 64% autologous) collected within the EBMT activity survey from 1990 to 2001 were used to assess trends over time, transplant rates and coefficient of variation (CV) of transplant rates among European countries for acute myeloid leukemia (AML; 18.5%), acute lymphocytic leukemia (ALL; 12%), chronic myeloid leukemia (CML; 11.5%), myelodysplastic syndromes (MDS; 3%), lymphoproliferative disorders (LPS; 36.3%) and multiple myeloma (MM; 18.7%). Transplant rates increased in all countries and for all indications from 1990 to 2001 from 1.7-fold (CML) to 24.8-fold (MM). Transplant rates have declined for CML since 1999. Autologous HSCT are the preferred choice for LPS and MM, allogeneic HSCT for ALL and myeloid malignancies. CVs of less than 50% suggest consensus for allogeneic HSCT in AML, ALL, CML, MDS and NHL, for autologous HSCT in LPS and MM. These data give an overview of the current status of HSCT for hematological malignancies in Europe and provide objective information for health-care providers and patient counselling.