Augmented post-induction therapy for children with high-risk acute lymphoblastic leukemia and a slow response to initial therapy

Minimal Residual Disease–Guided Treatment Deintensification for Children With Acute Lymphoblastic Leukemia: Results From the Malaysia-Singapore Acute Lymphoblastic Leukemia 2003 Study

Purpose

To improve treatment outcome for childhood acute lymphoblastic leukemia (ALL), we designed the Malaysia-Singapore ALL 2003 study with treatment stratification based on presenting clinical and genetic features and minimal residual disease (MRD) levels measured by polymerase chain reaction targeting a single antigen-receptor gene rearrangement.

Patients and Methods

Five hundred fifty-six patients received risk-adapted therapy with a modified Berlin-Frankfurt-Münster–ALL treatment. High-risk ALL was defined by MRD ≥ 1 × 10−3 at week 12 and/or poor prednisolone response, BCR-ABL1, MLL gene rearrangements, hypodiploid less than 45 chromosomes, or induction failure; standard-risk ALL was defined by MRD ≤ 1 × 10−4 at weeks 5 and 12 and no extramedullary involvement or high-risk features. Intermediate-risk ALL included all remaining patients.

Results

Patients who lacked high-risk presenting features (85.7%) received remission induction therapy with dexamethasone, vincristine, and asparaginase, without anthracyclines. Six-year event-free survival (EFS) was 80.6% ± 3.5%; overall survival was 88.4% ± 3.1%. Standard-risk patients (n = 172; 31%) received significantly deintensified subsequent therapy without compromising EFS (93.2% ± 4.1%). High-risk patients (n = 101; 18%) had the worst EFS (51.8% ± 10%); EFS was 83.6% ± 4.9% in intermediate-risk patients (n = 283; 51%).

Conclusion

Our results demonstrate significant progress over previous trials in the region. Three-drug remission-induction therapy combined with MRD-based risk stratification to identify poor responders is an effective strategy for childhood ALL.

Outcomes after induction failure in childhood acute lymphoblastic leukemia

BACKGROUND

Failure of remission-induction therapy is a rare but highly adverse event in children and adolescents with acute lymphoblastic leukemia (ALL).

METHODS

We identified induction failure, defined by the persistence of leukemic blasts in blood, bone marrow, or any extramedullary site after 4 to 6 weeks of remission-induction therapy, in 1041 of 44,017 patients (2.4%) 0 to 18 years of age with newly diagnosed ALL who were treated by a total of 14 cooperative study groups between 1985 and 2000. We analyzed the relationships among disease characteristics, treatments administered, and outcomes in these patients.

RESULTS

Patients with induction failure frequently presented with high-risk features, including older age, high leukocyte count, leukemia with a T-cell phenotype, the Philadelphia chromosome, and 11q23 rearrangement. With a median follow-up period of 8.3 years (range, 1.5 to 22.1), the 10-year survival rate (±SE) was estimated at only 32±1%. An age of 10 years or older, T-cell leukemia, the presence of an 11q23 rearrangement, and 25% or more blasts in the bone marrow at the end of induction therapy were associated with a particularly poor outcome. High hyperdiploidy (a modal chromosome number >50) and an age of 1 to 5 years were associated with a favorable outcome in patients with precursor B-cell leukemia. Allogeneic stem-cell transplantation from matched, related donors was associated with improved outcomes in T-cell leukemia. Children younger than 6 years of age with precursor B-cell leukemia and no adverse genetic features had a 10-year survival rate of 72±5% when treated with chemotherapy only.

CONCLUSIONS

Pediatric ALL with induction failure is highly heterogeneous. Patients who have T-cell leukemia appear to have a better outcome with allogeneic stem-cell transplantation than with chemotherapy, whereas patients who have precursor B-cell leukemia without other adverse features appear to have a better outcome with chemotherapy. (Funded by Deutsche Krebshilfe and others.).

Development and refinement of augmented treatment regimens for pediatric high-risk acute lymphoblastic leukemia

The 5-year survival rate for children and adolescents with acute lymphoblastic leukemia (ALL) is now at least 90%. However, clinical features (age and initial white blood cell count [WBC]), early treatment response, and the presence/absence of specific sentinel genomic lesions can identify subsets of high-risk (HR) ALL patients with a much higher risk of treatment failure. Chemotherapy regimens used to treat HR ALL have been refined over the past 3 decades through randomized clinical trials conducted by the Children's Oncology Group (COG) in North America and the Berlin-Frankfurt-Muenster (BFM) group in Western Europe. Contemporary COG HR ALL treatment regimens were developed from the BFM-76 regimen, with subsequent changes that led to development and refinement of a so-called augmented BFM (ABFM) regimen used today. Although contemporary COG and BFM treatment regimens are not identical, there are many more similarities than differences. With improvements in survival, it has become clear that although the outcome of some patients with HR ALL can be improved by optimizing use of standard cytotoxic chemotherapy agents, this approach has had only limited success for other patient subsets. In contrast, introduction of the tyrosine kinase inhibitor imatinib has led to dramatic outcome improvements for children and adolescents with Philadelphia chromosome-positive ALL. Genomic studies are identifying new sentinel genomic lesions that can serve as potential therapeutic targets, which will likely lead to the testing of novel and/or targeted therapies in more children with HR ALL. Such studies will require increased collaboration between Western European and North American cooperative groups.

Resveratrol given intraperitoneally does not inhibit the growth of high-risk t(4;11) acute lymphoblastic leukemia cells in a NOD/SCID mouse model

The efficacy of resveratrol as a preventive agent against the growth of t(4;11) acute lymphoblastic leukemia (ALL) was evaluated in NOD.CB17-Prkdcscid/J mice engrafted with the human t(4;11) ALL SEM cell line. SEM cells were injected into the tail vein and engraftment was monitored by flow cytometry. Once engraftment was observed, mice were injected intraperitoneally with resveratrol (10 mg/kg body weight) dissolved in dimethylsulfoxide (DMSO) or DMSO alone (control) every other day, or vincristine (0.5 mg/kg body weight) 3 times per week for 4 weeks (n=16 per group). Comparisons of the percent of human leukemia cells in blood and survival curves showed resveratrol did not inhibit progression of the disease. Liquid chromatography-tandem mass spectrometry analyses of mouse sera showed resveratrol was rapidly metabolized to glucuronidated and sulfated forms 1 h post-injection, with low to no resveratrol or metabolites observed in sera by 24-48 h. These data indicate that in contrast to findings in in vitro models, parenterally administered resveratrol does not have potential as a preventive agent against high risk t(4;11) ALL.

Augmented therapy improves outcome for pediatric high risk acute lymphocytic leukemia: results of Children's Oncology Group trial P9906

BACKGROUND

The augmented BFM regimen improves outcome for children with NCI high acute lymphoblastic leukemia (ALL). Patient age, sex, and presenting white blood cell count (WBC) can be used to identify a subset of approximately 12% of children with B-precursor ALL that had a 5-year continuous complete remission (CCR) rate of only about 50% on earlier Pediatric Oncology Group (POG) trials.

PROCEDURES

Children's Oncology Group trial P9906 evaluated a modified augmented BFM regimen in 267 patients with particularly high risk B-precursor ALL. Minimal residual disease (MRD) was assessed in blood at day 8 and in marrow at day 29 of induction and correlated with outcome.

RESULTS

The 5-year CCR probability for patients in P9906 was significantly better than that observed for similar patients on POG trials 8602/9006 (62.2 ± 3.7% vs. 50.6 ± 2.4%; P = 0.0007) but similar to POG 9406 (63.5 ± 2.4%; P = 0.81). Interim analysis showed poor central nervous system (CNS) control, especially in patients with initial WBC ≥ 100,000/microliter. Day 29 marrow MRD positive (≥ 0.01%) vs. negative patients had 5 year CCR rates of 37.1 ± 7.4% vs. 72.6 ± 4.3%; day 8 blood MRD positive vs. negative patients had 5 year CCR rates of 57.1 ± 4.6% vs.83.6 ± 6.3%. End induction marrow MRD predicted marrow but not CNS relapse. In multivariate analysis, day 29 MRD > 0.01%, initial WBC ≥ 100,000/µl, male gender, and day 8 blood MRD > 0.01% were significant prognostic factors.

CONCLUSIONS

Augmented BFM therapy improved outcome for children with higher risk ALL. Day 8 blood and day 29 marrow MRD were strong prognostic factors in these patients.

Key pathways are frequently mutated in high-risk childhood acute lymphoblastic leukemia: a report from the Children's Oncology Group

We sequenced 120 candidate genes in 187 high-risk childhood B-precursor acute lymphoblastic leukemias, the largest pediatric cancer genome sequencing effort reported to date. Integrated analysis of 179 validated somatic sequence mutations with genome-wide copy number alterations and gene expression profiles revealed a high frequency of recurrent somatic alterations in key signaling pathways, including B-cell development/differentiation (68% of cases), the TP53/RB tumor suppressor pathway (54%), Ras signaling (50%), and Janus kinases (11%). Recurrent mutations were also found in ETV6 (6 cases), TBL1XR1 (3), CREBBP (3), MUC4 (2), ASMTL (2), and ADARB2 (2). The frequency of mutations within the 4 major pathways varied markedly across genetic subtypes. Among 23 leukemias expressing a BCR-ABL1-like gene expression profile, 96% had somatic alterations in B-cell development/differentiation, 57% in JAK, and 52% in both pathways, whereas only 9% had Ras pathway mutations. In contrast, 21 cases defined by a distinct gene expression profile coupled with focal ERG deletion rarely had B-cell development/differentiation or JAK kinase alterations but had a high frequency (62%) of Ras signaling pathway mutations. These data extend the range of genes that are recurrently mutated in high-risk childhood B-precursor acute lymphoblastic leukemia and highlight important new therapeutic targets for selected patient subsets.

[Absolute lymphocyte count as a prognostic factor in children with acute lymphoblastic leukemia]

INTRODUCTION

Recent studies have suggested that the absolute lymphocyte count (ALC) may be a prognostic indicator in malignant diseases, in that those patients who have higher ALC at certain times during treatment may have a better chance of survival. The influence of T cells and natural killer cells in the immune system of the patient with cancer as a response to cancer cells is particularly noted.

MATERIALS AND METHOD

We prospectively assessed the prognostic value of absolute lymphocytic count (ALC) in 105 pediatric patients with acute lymphoblastic leukemia (ALL), treated in the Cuban Immunology and Hematology Institute from 1995 to 2008. ALC was studied at days 15 (ALC-15) and 28 (ALC-28) of treatment.

RESULTS

In our patients, 1000 cells/uL was the median ALC value for patients who relapsed or died. Using 1000/uL we found that ALL patients with an ALC-15 <1000 cells/μl had a 5-year relapse free survival (RFS) of 51%. In contrast, an ALC-15 >1000 cells/uL showed an excellent prognosis, with a 5-year RFS of 83% (p=0.02). Similarly in our study, an ALC-28 <1000 cells/μl predicted a 5-year overall survival (OS) of 66%, whereas an ALC-28 >1000 cells/μl predicted excellent outcome, with a 5-year OS of 86% (p=0.01). Importantly, ALC is also a strong predictor in multivariate analysis with known prognostic factors. ALC is a simple, statistically powerful measurement for patients with de novo ALL.

CONCLUSIONS

The results, when combined with previous studies, demonstrate that ALC is a powerful new prognostic factor for a range of malignancies.

Minimal residual disease in peripheral blood at day 15 identifies a subgroup of childhood B-cell precursor acute lymphoblastic leukemia with superior prognosis

BACKGROUND

Most minimal residual disease-directed treatment interventions in current treatment protocols for acute lymphoblastic leukemia are based on bone marrow testing, which is a consequence of previous studies showing the superiority of bone marrow over peripheral blood as an investigational material. Those studies typically did not explore the prognostic impact of peripheral blood involvement and lacked samples from very early time points of induction.

DESIGN AND METHODS

In this study, we employed real-time quantitative polymerase chain reaction analysis to examine minimal residual disease in 398 pairs of blood and bone marrow follow-up samples taken from 95 children with B-cell precursor acute lymphoblastic leukemia treated with the ALL IC-BFM 2002 protocol.

RESULTS

We confirmed the previously published poor correlation between minimal residual disease in blood and marrow at early treatment time points, with levels in bone marrow being higher than in blood in most samples (median 7.9-fold, range 0.04-8,293-fold). A greater involvement of peripheral blood at diagnosis was associated with a higher white blood cell count at diagnosis (P=0.003) and with enlargement of the spleen (P=0.0004) and liver (P=0.05). At day 15, a level of minimal residual disease in blood lower than 10(-4) was associated with an excellent 5-year relapse-free survival in 78 investigated patients (100% versus 69 ± 7%; P=0.0003). Subgroups defined by the level of minimal residual disease in blood at day 15 (high-risk: ≥ 10(-2), intermediate-risk: <10(-2) and ≥ 10(-4), standard-risk: <10(-4)) partially correlated with bone marrow-based stratification described previously, but the risk groups did not match completely. No other time point analyses were predictive of outcome in peripheral blood, except for a weak association at day 8.

CONCLUSIONS

Minimal residual disease in peripheral blood at day 15 identified a large group of patients with an excellent prognosis and added prognostic information to the risk stratification based on minimal residual disease at day 33 and week 12.

Escalating intravenous methotrexate improves event-free survival in children with standard-risk acute lymphoblastic leukemia: a report from the Children's Oncology Group

Children's Cancer Group-1991 selected 2 components from the Children's Cancer Group studies shown to be effective in high-risk acute lymphoblastic leukemia and examined them in children with National Cancer Institute standard-risk acute B-precursor lymphoblastic leukemia. These were (1) vincristine and escalating IV methotrexate (MTX) without leucovorin rescue during the interim maintenance (IM) phases and (2) addition of a second delayed intensification (DI) phase. Eligible patients (n = 2078) were randomly assigned to regimens containing either oral (PO) MTX, PO mercaptopurine, dexamethasone, and vincristine or IV MTX during IM phases, and regimens with either single DI or double DI. Five-year event-free survival (EFS) and overall survival for patients on the PO MTX arms were 88.7% ± 1.4% and 96% ± 0.9% versus 92.6% ± 1.2% and 96.5% ± 0.8% for those on the IV MTX arms (P = .009, P = .66). Five-year EFS and overall survival for patients who received single DI were 90.9% ± 1.3% and 97.1% ± 0.8% versus 90.5% ± 1.3% and 95.4% ± 3.8% for those who received double DI (P = .71, P = .12). No advantage was found for a second DI; however, replacement of PO MTX, PO mercaptopurine, vincristine, and dexamethasone during IM with vincristine and escalating IV MTX improved EFS.

Inducing apoptosis in chemotherapy-resistant B-lineage acute lymphoblastic leukaemia cells by targeting HSPA5, a master regulator of the anti-apoptotic unfolded protein response signalling network

We present previously unknown evidence that the immunoglobulin heavy chain binding protein BIP/HSPA5, also known as glucose regulated protein (GRP)78, serving as a pivotal component of the pro-survival axis of the unfolded protein response (UPR) signalling network, is abundantly expressed in relapsed B-lineage acute lymphoblastic leukaemia (ALL) and contributes to chemotherapy resistance of leukaemic B-cell precursors. The resistance of B-lineage ALL cells to the standard anti-leukaemic drug vincristine was overcome by the HSPA5 inhibitor epigallocatechin gallate, which inhibits the anti-apoptotic function of HSPA5 by targeting its ATP-binding domain. Notably, chemotherapy-resistant B-lineage ALL cells underwent apoptosis within 48 h of exposure to a doxorubicin-conjugated cell-penetrating cyclic anti-HSPA5 peptide targeting surface-expressed HSPA5 molecules on leukaemia cells. The identification of the HSPA5 as a chemoresistance biomarker and molecular target for B-lineage ALL may lead to new anti-leukaemic treatment strategies that are much needed.

Effectiveness of high-dose methotrexate in T-cell lymphoblastic leukemia and advanced-stage lymphoblastic lymphoma: a randomized study by the Children's Oncology Group (POG 9404)

The Pediatric Oncology Group (POG) phase 3 trial 9404 was designed to determine the effectiveness of high-dose methotrexate (HDM) when added to multi-agent chemotherapy based on the Dana-Farber backbone. Children with T-cell acute lymphoblastic leukemia (T-ALL) or advanced lymphoblastic lymphoma (T-NHL) were randomized at diagnosis to receive/not receive HDM (5 g/m² as a 24-hour infusion) at weeks 4, 7, 10, and 13. Between 1996 and 2000, 436 patients were enrolled in the methotrexate randomization. Five-year and 10-year event-free survival (EFS) was 80.2% ± 2.8% and 78.1% ± 4.3% for HDM (n = 219) versus 73.6% ± 3.1% and 72.6% ± 5.0% for no HDM (n = 217; P = .17). For T-ALL, 5-year and 10-year EFS was significantly better with HDM (n = 148, 5 years: 79.5% ± 3.4%, 10 years: 77.3% ± 5.3%) versus no HDM (n = 151, 5 years: 67.5% ± 3.9%, 10 years: 66.0% ± 6.6%; P = .047). The difference in EFS between HDM and no HDM was not significant for T-NHL patients (n = 71, 5 years: 81.7% ± 4.9%, 10 years: 79.9% ± 7.5% vs n = 66, 5 years: 87.8% ± 4.2%, 10 years: 87.8% ± 6.4%; P = .38). The frequency of mucositis was significantly higher in patients treated with HDM (P = .003). The results support adding HDM to the treatment of children with T-ALL, but not with NHL, despite the increased risk of mucositis.

Isolated extramedullary relapse in childhood acute lymphocytic leukemia

Although the vast majority of children with acute lymphocytic leukemia attain remission with modern therapies, an unacceptably high number will suffer a disease relapse. Both the duration of remission and the site of relapse are important prognostic factors. This review focuses on leukemic relapse isolated to sites outside the bone marrow (extramedullary sites). Data from cooperative study groups as well as large single institutions are reviewed with respect to the incidence of isolated extramedullary relapse as well as the outcome following relapse. The unique anatomic and physiologic properties of the testes and the central nervous system-the two most common sites of isolated extramedullary relapse-are discussed. Finally, the evolution of leukemia therapy is reviewed, bringing into focus the goals and challenges of future therapeutic endeavors.

Common Viral Pneumonia

Common respiratory viruses are now recognised as true opportunistic respiratory pathogens in patients with haematological malignancies. The epidemiology of these viruses has not been extensively studied in immunocompromised hosts, but is probably closely related to viral activity in immunocompetent hosts, who constitute the virus reservoir for immunocompromised patients. In these patients, common respiratory viruses may cause severe infections with higher rates of progression to pneumonia and mortality compared to immunocompetent individuals. Prolonged high-titre viral shedding is common in patients with haematological malignancies and may enhance not only viral transmission, but also the selection of resistant strains. Influenza and respiratory syncytial virus (RSV) infections have been particularly well studied. They are associated with pneumonia rates of about one-third for influenza and 30–40% for RSV. Both viruses are responsible for mortality rates ranging from 15% to 30%. The exact mechanisms of pneumonia related to these viruses remains unknown, but bacterial and fungal co-infections are frequent and must be carefully investigated. Parainfluenza viruses (PIV) and RSV have also been linked to late airflow obstruction in haematopoietic stem cell transplant recipients. Neuraminidase inhibitor therapy has been suggested for influenza, ribavirin for RSV, and cidofovir for adenovirus infections. However, there is no evidence supporting the use of these drugs, and randomised controlled trials are urgently needed to better define the optimal management of common viral pneumonia in patients with haematological malignancies. The absence of proven effective treatments highlights the critical importance of prevention. Viral transmission may be interrupted by contact isolation with droplet precautions for infected patients and by having patients and health care workers with suspected infection, and their relatives, refrain from visits and work. Immunisation remains the cornerstone of influenza prevention and is recommended for patients with haematological malignancies, their relatives, and health care workers.

Postrelapse survival in childhood acute lymphoblastic leukemia is independent of initial treatment intensity: a report from the Children's Oncology Group

While intensification of therapy has improved event-free survival (EFS) and survival in newly diagnosed children with acute lymphoblastic leukemia (ALL), postrelapse outcomes remain poor. It might be expected that patients relapsing after inferior initial therapy would have a higher retrieval rate than after superior therapy. In the Children's Oncology Group Study CCG-1961, significantly superior EFS and survival were achieved with an augmented (stronger) versus standard intensity regimen of postinduction intensification (PII) for children with newly diagnosed high-risk ALL and rapid day 7 marrow response (EFS/survival 81.2%/88.7% vs 71.7%/83.4%, respectively). This provided an opportunity to evaluate postrelapse survival (PRS) in 272 relapsed patients who had received randomly allocated initial treatment with augmented or standard intensity PII. As expected, PRS was worse for early versus late relapse, marrow versus extramedullary site, adolescent versus younger age and T versus B lineage. However, no difference in 3-year PRS was detected for having received augmented versus standard intensity PII (36.4% ± 5.7% vs 39.2% ± 4.1%; log rank P = .72). Similar findings were noted within subanalyses by timing and site of relapse, age, and immunophenotype. These findings provide insight into mechanisms of relapse in ALL, and are consistent with emergence of a resistant subclone that has acquired spontaneous mutations largely independent of initial therapy. This study is registered at www.clinicaltrials.gov as NCT00002812.

Defining the course and prognosis of adults with acute lymphocytic leukemia in first salvage after induction failure or short first remission duration

BACKGROUND

Results from salvage therapy in adult patients with acute lymphocytic leukemia (ALL) are wide-ranging and depend on several disease and patient characteristics. The objectives of this study were to define the prognosis for adult patients with ALL after first salvage through multivariate analyses of patient and disease characteristics.

METHODS

Adults with ALL who had primary resistance to frontline therapy or who had a disease recurrence after a first complete response (CR) duration <1 year were analyzed. Multivariate analyses for subsequent CR and survival were conducted.

RESULTS

Seventy-five of 245 patients (31%) achieved CR. The median CR duration was 5 months, the median survival was 4.7 months. In multivariate analysis, independent poor prognostic factors for not achieving CR were age >55 years, bone marrow blasts ≥20%, and platelet count <75 × 10(9) /L. Variables that were associated independently with shorter survival were age >55 years, bone marrow blasts ≥20%, platelet count <75 × 10(9) /L, albumin level <3 g/L, and lactic dehydrogenase level ≥1000 IU/L. Patients who had ≥3 of the 5 adverse factors (45%) had a median survival of 2 to 3 months and CR rates of 8% to 15%. Achieving CR was associated independently with improved survival in a landmark multivariate analysis (P < .0001; hazard ratio, 0.40; 95% confidence interval, 0.03-0.72).

CONCLUSIONS

The current analyses identified a subset of adults patients ALL in first salvage for whom standard therapies were associated with an extremely poor outcome. The results also confirmed the importance of achieving CR to attain improved survival.

Effect of mitoxantrone on outcome of children with first relapse of acute lymphoblastic leukaemia (ALL R3): an open-label randomised trial

BACKGROUND

Although survival of children with acute lymphoblastic leukaemia has improved greatly in the past two decades, the outcome of those who relapse has remained static. We investigated the outcome of children with acute lymphoblastic leukaemia who relapsed on present therapeutic regimens.

METHODS

This open-label randomised trial was undertaken in 22 centres in the UK and Ireland and nine in Australia and New Zealand. Patients aged 1-18 years with first relapse of acute lymphoblastic leukaemia were stratified into high-risk, intermediate-risk, and standard-risk groups on the basis of duration of first complete remission, site of relapse, and immunophenotype. All patients were allocated to receive either idarubicin or mitoxantrone in induction by stratified concealed randomisation. Neither patients nor those giving interventions were masked. After three blocks of therapy, all high-risk group patients and those from the intermediate group with postinduction high minimal residual disease (≥10(-4) cells) received an allogenic stem-cell transplant. Standard-risk and intermediate-risk patients with postinduction low minimal residual disease (<10(-4) cells) continued chemotherapy. The primary outcome was progression-free survival and the method of analysis was intention-to-treat. Randomisation was stopped in December, 2007 because of differences in progression-free and overall survival between the two groups. This trial is registered, reference number ISCRTN45724312.

FINDINGS

Of 239 registered patients, 216 were randomly assigned to either idarubicin (109 analysed) or mitoxantrone (103 analysed). Estimated 3-year progression-free survival was 35·9% (95% CI 25·9-45·9) in the idarubicin group versus 64·6% (54·2-73·2) in the mitoxantrone group (p=0·0004), and 3-year overall survival was 45·2% (34·5-55·3) versus 69·0% (58·5-77·3; p=0·004). Differences in progression-free survival between groups were mainly related to a decrease in disease events (progression, second relapse, disease-related deaths; HR 0·56, 0·34-0·92, p=0·007) rather than an increase in adverse treatment effects (treatment death, second malignancy; HR 0·52, 0·24-1·11, p=0·11).

INTERPRETATION

As compared with idarubicin, mitoxantrone conferred a significant benefit in progression-free and overall survival in children with relapsed acute lymphobastic leukaemia, a potentially useful clinical finding that warrants further investigation.

FUNDING

Cancer Research UK, Leukaemia and Lymphoma Research, Cancer Council NSW, and Sporting Chance Cancer Foundation.

Adolescents and Young Adults with Acute Lymphoblastic Leukemia

During the last decade, increasing attention has been paid to a unique group of patients with acute lymphoblastic leukemia (ALL) who lie at the crossroad of therapeutic care by pediatric and adult hematologists/oncologists. ALL is a disease that affects infants, children, adolescents, and adult patients. With current therapies, the vast majority of children with ALL are now long-term survivors; unfortunately, the same good results have not yet been obtained for adults with ALL. This review will describe current controversies surrounding the treatment of adolescents and young adults with ALL—a group who finds themselves in the transition from “pediatric” to “adult” treatment approaches. The review focuses on recent insights into disease biology, prognostic factors, and treatment outcomes that have led to a series of prospective clinical trials specifically designed for adolescents and younger adults (AYAs) with ALL. These trials have been designed to provide important new clinical, psychosocial, and biological insights, and to further improve the survival of this challenging and unique group of patients.

Twenty-five years of treatment for childhood acute lymphoblastic leukaemia in Western Australia: how do we compare?

OBJECTIVES

To compare survival among the subgroup of children with acute lymphoblastic leukaemia (ALL) who were treated at Princess Margaret Hospital for Children (PMH) in Perth, Western Australia, over 25 years under 15 consecutive protocols of the Children's Cancer Group (CCG) with survival for the entire cohort of children in multiple centres treated under CCG protocols in that period; and to highlight the benefits of membership of a large cooperative research group conducting multicentre randomised controlled trials.

DESIGN, PARTICIPANTS AND SETTING

Retrospective review of the outcomes of all 311 children with newly diagnosed ALL treated at PMH between 1983 and 2008.

MAIN OUTCOME MEASURES

4-year event-free survival; and 10-year overall survival.

RESULTS

Four-year event-free survival for the entire PMH cohort increased from 66% (SE, 6%) for 1983-1987 to 88% (SE, 6%) for 2002-2005, while overall survival over the same period improved from 78% (SE, 5%) to 94% (SE, 4%). Comparisons of outcomes of children treated at PMH with those of the entire CCG cohort, protocol by protocol, revealed similar outcomes.

CONCLUSION

Outcomes of children treated at PMH over the 25-year period are equivalent to those of the larger CCG cohort.

Novel in vivo model of inducible multi-drug resistance in acute lymphoblastic leukemia with chromosomal translocation t(4;11)

Acute lymphoblastic leukemia (ALL) with translocation t(4;11) is found in 60-85% of infants with ALL and is often refractory to conventional chemotherapeutics after relapse. Using the t(4;11) ALL line SEM, we evaluated chemotherapy resistance in NOD.CB17-Prkdcscid/J mice. SEM cells were injected into the tail vein and engraftment was monitored by flow cytometry. Once engraftment was observed, mice were injected intraperitoneally with phosphate-buffered saline (PBS), or vincristine (0.5mg/kg body weight) three times per week for 4weeks (n=8 per group). The level of P-glycoprotein in SEM cells was increased 3-fold by vincristine treatment compared to PBS-treated mice. Survival curves showed that leukemia cell growth was initially delayed by vincristine treatment, but the mice eventually succumbed to disease. These data describe a novel inducible model for investigating multi-drug resistance mechanisms in high-risk t(4;11) ALL.

Tolerability and efficacy of L-asparaginase therapy in pediatric patients with acute lymphoblastic leukemia

L-asparaginase (L-ASNase) has been an essential component of multiagent chemotherapy for acute lymphoblastic leukemia in childhood for over 3 decades. There are currently 2 Food and Drug Administration (FDA)-approved formulations of L-ASNase derived from Escherichia coli and 1 non-FDA approved formulation derived from Erwinia chrysanthemi. Modifications in L-ASNase have included pegylation, which decreases drug immunogenicity and increases the half-life, allowing less frequent administration. Although L-ASNase is well-tolerated in most patients and causes little myelosuppression, significant toxicities occur in up to 30% of patients. Hypersensitivity is the most common toxicity of L-ASNase therapy and limits the further use of the drug. Other significant toxicities relate to a reduction in protein synthesis and include pancreatitis, thrombosis, central nervous system complications, and liver dysfunction. The spectrum of common toxicities and the efficacy of different formulations of L-ASNase are presented in this review.

Identification of novel cluster groups in pediatric high-risk B-precursor acute lymphoblastic leukemia with gene expression profiling: correlation with genome-wide DNA copy number alterations, clinical characteristics, and outcome

To resolve the genetic heterogeneity within pediatric high-risk B-precursor acute lymphoblastic leukemia (ALL), a clinically defined poor-risk group with few known recurring cytogenetic abnormalities, we performed gene expression profiling in a cohort of 207 uniformly treated children with high-risk ALL. Expression profiles were correlated with genome-wide DNA copy number abnormalities and clinical and outcome features. Unsupervised clustering of gene expression profiling data revealed 8 unique cluster groups within these high-risk ALL patients, 2 of which were associated with known chromosomal translocations (t(1;19)(TCF3-PBX1) or MLL), and 6 of which lacked any previously known cytogenetic lesion. One unique cluster was characterized by high expression of distinct outlier genes AGAP1, CCNJ, CHST2/7, CLEC12A/B, and PTPRM; ERG DNA deletions; and 4-year relapse-free survival of 94.7% ± 5.1%, compared with 63.5% ± 3.7% for the cohort (P = .01). A second cluster, characterized by high expression of BMPR1B, CRLF2, GPR110, and MUC4; frequent deletion of EBF1, IKZF1, RAG1-2, and IL3RA-CSF2RA; JAK mutations and CRLF2 rearrangements (P < .0001); and Hispanic ethnicity (P < .001) had a very poor 4-year relapse-free survival (21.0% ± 9.5%; P < .001). These studies reveal striking clinical and genetic heterogeneity in high-risk ALL and point to novel genes that may serve as new targets for diagnosis, risk classification, and therapy.

Randomized trial to compare LSA2L2-type maintenance therapy to daily 6-mercaptopurine and weekly methotrexate with vincristine and dexamethasone pulse for children with acute lymphoblastic leukemia

BACKGROUND

A total of 201 pediatric cases of acute lymphoblastic leukemia were treated with the ALL-96 protocol by the Kyushu-Yamaguchi Children's Cancer Study Group.

PROCEDURE

Risk stratification was based on white cell counts, immunophenotype, the presence of central nervous system disease at diagnosis, organomegaly, and early treatment response (day 14 bone marrow status). All of the patients were classified into standard-risk (SR) or high-risk (HR) groups and were randomly assigned to receive maintenance therapy with either LSA2L2-type or 6-mercaptopurine (6-MP)/methotrexate (MTX) with vincristine (VCR) and dexamethasone (DEX) pulse in both risk groups.

RESULTS

The 7-year event-free survival (EFS) and overall survival (OS) rates in the entire study population were 72.1% (95% CI: 68.0-76.2%) and 84.8% (95% CI: 79.7-89.9%), respectively, and the EFS of the SR patients (85.3% [95% CI: 78.2-92.4%]) was significantly better than HR patients (62.4% [95% CI: 52.2-72.6%]) (P = 0.0007).

CONCLUSIONS

There were no differences in the EFS between the different maintenance therapies in each risk group; however, grade IV liver toxicity occurred more often in the patients receiving 6-MP/MTX with VCR and DEX therapy than in patients receiving LSA2L2.

Leukemias and lymphomas: treatment and prophylaxis of the central nervous system

Central nervous system (CNS)-directed therapy is required for many acute leukemia patients and for nearly all aggressive or high-grade non-Hodgkin's lymphoma patients as part of an overall chemotherapy plan for disease eradication. The CNS therapy decisions differ for overt disease treatment versus prophylactic treatment and take into consideration the type of leukemia or lymphoma, the age of the patient, and other prognostic factors. A variety of CNS-directed therapies are used for prevention or treatment of CNS disease in acute leukemias or aggressive lymphomas: intrathecal medications (cytosine arabinoside, methotrexate, or both in combination with hydrocortisone) with or without cranial or craniospinal irradiation, intrathecal medication only with intensive systemic chemotherapy, or high-dose chemotherapy specifically chosen for CNS penetrance. Any type of CNS-directed therapy, whether intrathecal chemotherapy, high-dose systemic chemotherapy, or irradiation, may cause acute or delayed (late) toxicity. Ongoing clinical trial research aims to reduce the risk of toxicity from CNS-directed therapy while preserving or improving treatment efficacy.

Down syndrome childhood acute lymphoblastic leukemia has a unique spectrum of sentinel cytogenetic lesions that influences treatment outcome: a report from the Children's Oncology Group

Children with Down syndrome (DS) have an increased risk of acute lymphoblastic leukemia (ALL) and an inferior outcome. We reviewed data from 2811 children with ALL enrolled in Children's Oncology Group P9900, which included prospective testing for the major cytogenetic lesions in childhood ALL: ETV6-RUNX1, TCF3-PBX1, BCR-ABL1, and MLL translocations and trisomies of chromosomes 4 and 10. Eighty (3%) B-precursor ALL patients had DS. Age, sex, white blood cell count, and risk group were similar between DS-ALL and non-DS-ALL but significantly more patients with DS-ALL were white (91.2% vs 76.4%, P = .001). Children with DS-ALL had lower rates of the favorable cytogenetic lesions ETV6-RUNX1 (2.5% vs 24%, P < .001) and trisomies 4 and 10 (7.7% vs 24%, P < .001). Five-year event-free (EFS) and overall survival (OS) were inferior in children with DS-ALL: 69.9% +/- 8.6% versus 78.1% +/- 1.2% (P = .078), and 85.8% +/- 6.5% versus 90.0% +/- 0.9% (P = .033). However, when children with MLL translocations, BCR-ABL1, ETV6-RUNX1, and trisomies 4 and 10 were excluded, the EFS and OS were similar for children with and without DS (EFS 68.0 %+/- 9.3% vs 70.5% +/- 1.9%, P = .817; and OS 86.7% +/- 6.7% vs 85.4% +/- 1.5%; P = .852), both overall and adjusted for race. DS-ALL displays a unique spectrum of biologic subtypes with different frequencies of sentinel cytogenetic lesions having a large influence on outcome.

Outcomes for children and adolescents with cancer: challenges for the twenty-first century

PURPOSE

This report provides an overview of current childhood cancer statistics to facilitate analysis of the impact of past research discoveries on outcome and provide essential information for prioritizing future research directions.

METHODS

Incidence and survival data for childhood cancers came from the Surveillance, Epidemiology, and End Results 9 (SEER 9) registries, and mortality data were based on deaths in the United States that were reported by states to the Centers for Disease Control and Prevention by underlying cause.

RESULTS

Childhood cancer incidence rates increased significantly from 1975 through 2006, with increasing rates for acute lymphoblastic leukemia being most notable. Childhood cancer mortality rates declined by more than 50% between 1975 and 2006. For leukemias and lymphomas, significantly decreasing mortality rates were observed throughout the 32-year period, though the rate of decline slowed somewhat after 1998. For remaining childhood cancers, significantly decreasing mortality rates were observed from 1975 to 1996, with stable rates from 1996 through 2006. Increased survival rates were observed for all categories of childhood cancers studied, with the extent and temporal pace of the increases varying by diagnosis.

CONCLUSION

When 1975 age-specific death rates for children are used as a baseline, approximately 38,000 childhood malignant cancer deaths were averted in the United States from 1975 through 2006 as a result of more effective treatments identified and applied during this period. Continued success in reducing childhood cancer mortality will require new treatment paradigms building on an increased understanding of the molecular processes that promote growth and survival of specific childhood cancers.

Rearrangement of CRLF2 is associated with mutation of JAK kinases, alteration of IKZF1, Hispanic/Latino ethnicity, and a poor outcome in pediatric B-progenitor acute lymphoblastic leukemia

Gene expression profiling of 207 uniformly treated children with high-risk B-progenitor acute lymphoblastic leukemia revealed 29 of 207 cases (14%) with markedly elevated expression of CRLF2 (cytokine receptor-like factor 2). Each of the 29 cases harbored a genomic rearrangement of CRLF2: 18 of 29 (62%) had a translocation of the immunoglobulin heavy chain gene IGH@ on 14q32 to CRLF2 in the pseudoautosomal region 1 of Xp22.3/Yp11.3, whereas 10 (34%) cases had a 320-kb interstitial deletion centromeric of CRLF2, resulting in a P2RY8-CRLF2 fusion. One case had both IGH@-CRLF2 and P2RY8-CRLF2, and another had a novel CRLF2 rearrangement. Only 2 of 29 cases were Down syndrome. CRLF2 rearrangements were significantly associated with activating mutations of JAK1 or JAK2, deletion or mutation of IKZF1, and Hispanic/Latino ethnicity (Fisher exact test, P < .001 for each). Within this cohort, patients with CRLF2 rearrangements had extremely poor treatment outcomes compared with those without CRLF2 rearrangements (35.3% vs 71.3% relapse-free survival at 4 years; P < .001). Together, these observations suggest that activation of CRLF2 expression, mutation of JAK kinases, and alterations of IKZF1 cooperate to promote B-cell leukemogenesis and identify these pathways as important therapeutic targets in this disease.

Long-term results of the pediatric oncology group studies for childhood acute lymphoblastic leukemia 1984-2001: a report from the children's oncology group

From 1984 to 2001, the Pediatric Oncology Group (POG) conducted 12 acute lymphoblastic leukemia (ALL) studies. Ten-year event-free survival (EFS) for patients >12 months of age with B-precursor ALL on acute leukemia in children 14, 15 and 16 series were 66.7+/-1.2%, 68.1+/-1.4% and 73.2+/-2.1%, respectively. Intermediate dose methotrexate (ID MTX; 1 g/m(2)) improved outcomes for standard risk patients (10-year EFS 77.5+/-2.7% vs 66.3+/-3.1% for oral MTX). Neither MTX intensification (2.5 g/m(2)) nor addition of cytosine arabinoside/daunomycin/teniposide improved outcomes for higher risk patients. Intermediate dose mercaptopurine (1 g/m(2)) failed to improve outcomes for either group. Ten-year EFS for patients with T-cell ALL, POG 8704 and 9404 were 49.1+/-3.1% and 72.2+/-4.7%, respectively. Intensive asparaginase (10-year EFS 61.8 vs 42.7%) and high-dose MTX (5 g/m(2)) (10-year EFS 78.0 vs 65.8%) improved outcomes. There was a non-significant improvement in EFS for infants (10-year EFS 17.7+/-7.2-31.9+/-8.3%). Prognostic indicators for B-precursor ALL were age and WBC at diagnosis, gender, central nervous system disease, DNA index and cytogenetic abnormalities. Only gender was prognostic in T-cell ALL. In infants, WBC and MLL translocation were linked to inferior outcome.

Long-term results of the children's cancer group studies for childhood acute lymphoblastic leukemia 1983-2002: a Children's Oncology Group Report

The Children's Cancer Group enrolled 13 298 young people age <21 years on 1 of 16 protocols between 1983 and 2002. Outcomes were examined in three time periods, 1983-1988, 1989-1995, 1996-2002. Over the three intervals, 10-year event-free survival (EFS) for Rome/National Cancer Institute standard risk (SR) and higher risk (HR) B-precursor patients was 68 and 58%, 77 and 63%, and 78 and 67%, respectively, whereas for SR and HR T-cell patients, EFS was 65 and 56%, 78 and 68%, and 70 and 72%, respectively. Five-year EFS for infants was 36, 38, and 43%, respectively. Seminal randomized studies led to a number of important findings. Stronger post-induction intensification improved outcome for both SR and HR patients. With improved systemic therapy, additional intrathecal (IT) methotrexate effectively replaced cranial radiation. For SR patients receiving three-drug induction, iso-toxic substitution of dexamethasone for prednisone improved EFS. Pegylated asparaginase safely and effectively replaced native asparaginase. Thus, rational therapy modifications yielded better outcomes for both SR and HR patients. These trials provide the platforms for current Children's Oncology Group trials.

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.

Outcome of adults with acute lymphocytic leukemia in second or subsequent complete remission

The outcome of adults with acute lymphocytic leukemia (ALL) who achieve a complete response (CR) on salvage therapy is thought to be poor, but not previously analyzed. To define the course of adult ALL post CR on salvage therapy and the effects of pretreatment factors on prognosis. One hundred seventy-two adults with ALL who achieved a second or third CR on salvage therapy were reviewed. Prognostic factors affecting survival were analyzed by multivariate analysis. The median survival post achieving CR for the entire group was 10 months. The estimated 1-year survival rate was 42%. Forty-three patients underwent stem cell transplant in subsequent CR: their median survival was 12 months and the 3-year survival rate was 25%. Independent poor prognostic factors for survival were age  > 55 years, duration of first CR < 12 months, and lactate dehydrogenase levels > 1000 IU/L. This analysis defines the outcome of adult ALL in CR post salvage therapy and the prognostic factors influencing survival. These results could be used in assessing the efficacy of new treatments aimed at improving CR durations and survival post salvage therapy.

High-risk childhood acute lymphoblastic leukemia

Although most children with acute lymphoblastic leukemia (ALL) are cured, certain subsets have a high risk of relapse. Relapse risk can be predicted by early response to therapy, clinical and pharmacogenetic features of the host, and genetic characteristics of leukemic cells. Though early treatment response can be assessed by the peripheral blast cell count after 1 week of single-agent glucocorticoid treatment or percent of bone marrow blasts by morphology after 1 or 2 weeks of multiagent induction treatment, determination of minimal residual disease by polymerase chain reaction (PCR) or flow cytometry after 2 to 6 weeks of induction is the most precise and useful measure. Augmented therapy has improved outcome for the poor responders to initial treatment. Infants with mixed-lineage leukemia (MLL)-rearranged ALL comprise a very poor-risk group wherein further intensification of chemotherapy causes significant toxicity. Hybrid protocols incorporating drugs effective for acute myeloid leukemia could improve survival, a strategy being tested in international trials. Studies on the biology of MLL-induced leukemogenesis have prompted the development of novel targeted agents, currently under evaluation in clinical trials. Short-term outcomes of patients with Philadelphia chromosome (Ph)-positive ALL have improved significantly by adding tyrosine kinase inhibitors to standard chemotherapy regimens. New agents and methods to overcome resistance are under investigation, and allogeneic stem cell transplantation is recommended for certain subsets of patients, for example those with Ph+ and T-cell ALL with poor early response. Genome-wide interrogation of leukemic cell genetic abnormalities and germline genetic variations promise to identify new molecular targets for therapy.

Risk-adapted treatment of pediatric acute lymphoblastic leukemia

Optimal use of antileukemic agents and stringent application of risk-directed therapy in clinical trials have resulted in steady improvement in the outcome of children with acute lymphoblastic leukemia, with current cure rates exceeding 80% in developed countries. The intensity of treatment varies substantially among subsets of patients, as therapy is designed to reduce acute and long-term toxicity in low-risk groups while improving outcomes in poor risk groups by treatment intensification. Recent advances in genome-wide screening techniques, pharmacogenomic studies, and development of molecular therapeutics are ushering in an era of more refined personalized therapy.

Long-term follow-up of the United Kingdom medical research council protocols for childhood acute lymphoblastic leukaemia, 1980-2001

Between 1980 and 2001, the United Kingdom Medical Research Council Childhood Leukemia Working Party has conducted 4 clinical trial in acute lymphoblastic leukemia, which have recruited a total of 6516 patients. UKALL VIII examined the role of daunorubicin in induction chemotherapy, and UKALL X examined the role of post-induction intensification. Both resulted in major improvement in the outcomes. UKALL XI examined the efficacy of different methods of CNS-directed therapy and the effects of an additional intensification. ALL97, which was initially based on the UKALL X D template (two intensification phases), examined the role of different steroids in induction and different thiopurines through continuing chemotherapy. A reappraisal of results from UKALL XI compared to other cooperative group results led to a redesign in 1999, which subsequently resulted in a major improvement in outcomes. Additionally, ALL97 and 97/99 demonstrated a significant advantage for the use of dexamethasone rather than prednisolone; although the use of 6-thioguanine resulted in fewer relapses, this advantage was offset by an increased incidence of deaths in remission. Over the era encompassed by these four trials there has been a major improvement in both event-free and overall survival for children in the UK with ALL.

Long-term results of five consecutive trials in childhood acute lymphoblastic leukemia performed by the ALL-BFM study group from 1981 to 2000

Between 1981 and 2000, 6609 children (<18 years of age) were treated in five consecutive trials of the Berlin-Frankfurt-Münster (BFM) study group for childhood acute lymphoblastic leukemia (ALL). Patients were treated in up to 82 centers in Germany, Austria and Switzerland. Probability of 10-year event-free survival (EFS) (survival) improved from 65% (77%) in study ALL-BFM 81 to 78% (85%) in ALL-BFM 95. In parallel to relapse reduction, major efforts focused on reducing acute and late toxicity through advanced risk adaptation of treatment. The major findings derived from these ALL-BFM trials were as follows: (1) preventive cranial radiotherapy could be safely reduced to 12 Gy in T-ALL and high-risk (HR) ALL patients, and eliminated in non- HR non-T-ALL patients, if it was replaced by high-dose and intrathecal (IT) MTX; (2) omission of delayed re-intensification severely impaired outcome of low-risk patients; (3) 6-month-less maintenance therapy caused an increase in systemic relapses; (4) slow response to an initial 7-day prednisone window was identified as adverse prognostic factor; (5) condensed induction therapy resulted in significant improvement of outcome; (6) the daunorubicin dose in induction could be safely reduced in low-risk patients and (7) intensification of consolidation/re-intensification treatment led to considerable improvement of outcome in HR patients.

Gene expression classifiers for relapse-free survival and minimal residual disease improve risk classification and outcome prediction in pediatric B-precursor acute lymphoblastic leukemia

To determine whether gene expression profiling could improve outcome prediction in children with acute lymphoblastic leukemia (ALL) at high risk for relapse, we profiled pretreatment leukemic cells in 207 uniformly treated children with high-risk B-precursor ALL. A 38-gene expression classifier predictive of relapse-free survival (RFS) could distinguish 2 groups with differing relapse risks: low (4-year RFS, 81%, n = 109) versus high (4-year RFS, 50%, n = 98; P < .001). In multivariate analysis, the gene expression classifier (P = .001) and flow cytometric measures of minimal residual disease (MRD; P = .001) each provided independent prognostic information. Together, they could be used to classify children with high-risk ALL into low- (87% RFS), intermediate- (62% RFS), or high- (29% RFS) risk groups (P < .001). A 21-gene expression classifier predictive of end-induction MRD effectively substituted for flow MRD, yielding a combined classifier that could distinguish these 3 risk groups at diagnosis (P < .001). These classifiers were further validated on an independent high-risk ALL cohort (P = .006) and retainedindependent prognostic significance (P < .001) in the presence of other recently described poor prognostic factors (IKAROS/IKZF1 deletions, JAK mutations, and kinase expression signatures). Thus, gene expression classifiers improve ALL risk classification and allow prospective identification of children who respond or fail current treatment regimens. These trials were registered at http://clinicaltrials.gov under NCT00005603.

Young adults with acute lymphoblastic leukemia have an excellent outcome with chemotherapy alone and benefit from intensive postinduction treatment: a report from the children's oncology group

PURPOSE

Patients 16 to 21 years of age with acute lymphoblastic leukemia (ALL) have an inferior outcome compared with younger children, leading some medical oncologists to advocate allogeneic stem-cell transplantation in first remission for these patients. We examined outcome for young adults with ALL enrolled onto the Children's Cancer Group (CCG) 1961 study between 1996 and 2002.

PATIENTS AND METHODS

CCG 1961 entered patients with ALL 1 to 21 years of age with initial WBC count > or = 50,000/microL and/or age > or = 10 years. Randomly assigned therapies evaluated the impact of postinduction treatment intensification on outcome. We examined outcome and prognostic factors for 262 young adults with ALL.

RESULTS

Five-year event-free and overall survival rates for young adult patients are 71.5% (SE, 3.6%) and 77.5% (SE, 3.3%), respectively. Rapid responder patients (< 25% bone marrow blasts on day 7) randomly assigned to augmented therapy had 5-year event-free survival of 81.8% (SE, 7%), as compared with 66.8% (SE, 6.7%) for patients receiving standard therapy (P = .07). One versus two interim maintenance and delayed intensification courses had no significant impact on event-free survival. WBC count more than 50,000/microL was an adverse prognostic factor.

CONCLUSION

Young adult patients with ALL showing a rapid response to induction chemotherapy benefit from early intensive postinduction therapy but do not benefit from a second interim maintenance and delayed intensification phase. Given the excellent outcome with this chemotherapy, there seems to be no role for the routine use of allogeneic stem-cell transplantation in first remission for young adults with ALL.

JAK mutations in high-risk childhood acute lymphoblastic leukemia

Pediatric acute lymphoblastic leukemia (ALL) is a heterogeneous disease consisting of distinct clinical and biological subtypes that are characterized by specific chromosomal abnormalities or gene mutations. Mutation of genes encoding tyrosine kinases is uncommon in ALL, with the exception of Philadelphia chromosome-positive ALL, where the t(9,22)(q34;q11) translocation encodes the constitutively active BCR-ABL1 tyrosine kinase. We recently identified a poor prognostic subgroup of pediatric BCR-ABL1-negative ALL patients characterized by deletion of IKZF1 (encoding the lymphoid transcription factor IKAROS) and a gene expression signature similar to BCR-ABL1-positive ALL, raising the possibility of activated tyrosine kinase signaling within this leukemia subtype. Here, we report activating mutations in the Janus kinases JAK1 (n = 3), JAK2 (n = 16), and JAK3 (n = 1) in 20 (10.7%) of 187 BCR-ABL1-negative, high-risk pediatric ALL cases. The JAK1 and JAK2 mutations involved highly conserved residues in the kinase and pseudokinase domains and resulted in constitutive JAK-STAT activation and growth factor independence of Ba/F3-EpoR cells. The presence of JAK mutations was significantly associated with alteration of IKZF1 (70% of all JAK-mutated cases and 87.5% of cases with JAK2 mutations; P = 0.001) and deletion of CDKN2A/B (70% of all JAK-mutated cases and 68.9% of JAK2-mutated cases). The JAK-mutated cases had a gene expression signature similar to BCR-ABL1 pediatric ALL, and they had a poor outcome. These results suggest that inhibition of JAK signaling is a logical target for therapeutic intervention in JAK mutated ALL.

Augmented and standard Berlin-Frankfurt-Munster chemotherapy for treatment of adult acute lymphoblastic leukemia

The augmented Berlin-Frankfurt-Munster (aBFM) regimen has demonstrated improved outcomes in children with acute lymphomblastic leukemia (ALL), but efficacy in adults is unknown. In this retrospective study, we evaluated clinical outcomes in 29 adult ALL patients (aged 19-70) treated with standard BFM (sBFM) or dose-intensive aBFM. Patients were stratified into risk groups based on age, cytogenetic abnormalities, peripheral leukocytosis and response to induction chemotherapy. Inter-mediate risk patients less than 50 years old and all high-risk patients were assigned to aBFM. Complete remission after induction therapy was achieved in 93% of patients. Fifteen patients completed a full course of BFM chemotherapy, with seven discontinuing because of relapse, three because of toxicity, two because of transplantation and two toxic deaths. Five-year event-free survival (EFS) was 45% (95% CI 30-67%), with 39% and 50% rates of EFS observed in the aBFM and sBFM subgroups at 5 years, respectively. Overall survival at 5 years was 62% (95% CI 46-82%), with 61% and 62% in the aBFM and sBFM subgroups alive at 5 years, respectively. Two toxic deaths were observed, and infections and neuropathy were the most common toxicities. sBFM and aBFM have efficacy and toxicity comparable with other adult ALL regimens.

Stopping or reporting early for positive results in randomized clinical trials: the National Cancer Institute Cooperative Group experience from 1990 to 2005

Randomized clinical trials are designed with stopping boundaries to guide data monitoring committees with their decision making concerning ongoing trials. In particular, when extremely positive results are seen and a boundary is crossed, the data monitoring committee may recommend releasing the results earlier to the public than at the definitive final analysis time specified in the protocol. For trials that are still accruing, this also means stopping accrual. Because the information about treatment efficacy is more limited in an early analysis than in a final analysis, questions have been raised about the appropriateness of incorporating early stopping for positive results in trial designs. In particular, there are concerns that treatment effects seen early may not be real or may be overly optimistic. To examine this issue, we collected information about treatment efficacy on National Cancer Institute Cooperative Group trials that were stopped early for positive results (information both at the time the trial was stopped/released and at times of further follow-up). Twenty-seven such trials were located. For 17 of 18 of these trials with sufficient follow-up information, the treatment effect was similar or only slightly smaller at last follow-up compared with the stopping/release time. We critically evaluate reasons why one might be concerned about early stopping for positive results. We conclude that for trials with well-designed interim monitoring plans, the ability to stop early for positive results is an important component of the trial design, allowing the public to benefit as soon as possible from the study conclusions.

Childhood acute lymphoblastic leukemia: update on prognostic factors

PURPOSE OF REVIEW

With current treatment regimens, event-free survival rates for childhood acute lymphoblastic leukemia (ALL) approach or exceed 80%. This success was achieved, in part, through the implementation of risk-stratified therapy. However, for the 15-20% of children with newly diagnosed ALL who will ultimately relapse, traditional risk assessment remains inadequate. This review highlights recent advances in our understanding of prognostic factors that may be used to refine risk group classification.

RECENT FINDINGS

An increasingly sophisticated understanding of genetic abnormalities in leukemia cells (including chromosomal abnormalities and patterns of gene expression), response to treatment, and host pharmacogenomics offers the potential to enhance or supplant currently applied prognostic criteria for use in treatment planning for childhood ALL.

SUMMARY

Identification of biologically distinctive subsets of ALL through cytogenetic, molecular, and gene expression studies, as well as investigations of minimal residual disease and host pharmacogenomics, offer promising avenues of research. Integration of molecular tools into clinical practice will ultimately allow for more precise risk stratification and individualized treatment planning.

Deletion of IKZF1 and prognosis in acute lymphoblastic leukemia

BACKGROUND

Despite best current therapy, up to 20% of pediatric patients with acute lymphoblastic leukemia (ALL) have a relapse. Recent genomewide analyses have identified a high frequency of DNA copy-number abnormalities in ALL, but the prognostic implications of these abnormalities have not been defined.

METHODS

We studied a cohort of 221 children with high-risk B-cell-progenitor ALL with the use of single-nucleotide-polymorphism microarrays, transcriptional profiling, and resequencing of samples obtained at diagnosis. Children with known very-high-risk ALL subtypes (i.e., BCR-ABL1-positive ALL, hypodiploid ALL, and ALL in infants) were excluded from this cohort. A copy-number abnormality was identified as a predictor of poor outcome, and it was then tested in an independent validation cohort of 258 patients with B-cell-progenitor ALL.

RESULTS

More than 50 recurring copy-number abnormalities were identified, most commonly involving genes that encode regulators of B-cell development (in 66.8% of patients in the original cohort); PAX5 was involved in 31.7% and IKZF1 in 28.6% of patients. Using copy-number abnormalities, we identified a predictor of poor outcome that was validated in the independent validation cohort. This predictor was strongly associated with alteration of IKZF1, a gene that encodes the lymphoid transcription factor IKAROS. The gene-expression signature of the group of patients with a poor outcome revealed increased expression of hematopoietic stem-cell genes and reduced expression of B-cell-lineage genes, and it was similar to the signature of BCR-ABL1-positive ALL, another high-risk subtype of ALL with a high frequency of IKZF1 deletion.

CONCLUSIONS

Genetic alteration of IKZF1 is associated with a very poor outcome in B-cell-progenitor ALL.