Relapsed lymphoblastic leukaemia in children: a continuing challenge

Temsirolimus combined with cyclophosphamide and etoposide for pediatric patients with relapsed/refractory acute lymphoblastic leukemia: a Therapeutic Advances in Childhood Leukemia Consortium trial (TACL 2014-001)

Phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling is commonly dysregulated in acute lymphoblastic leukemia (ALL). The TACL2014-001 phase I trial of the mTOR inhibitor temsirolimus in combination with cyclophosphamide and etoposide was performed in children and adolescents with relapsed/refractory ALL. Temsirolimus was administered intravenously (IV) on days 1 and 8 with cyclophosphamide 440 mg/m2 and etoposide 100 mg/m2 IV daily on days 1-5. The starting dose of temsirolimus was 7.5 mg/m2 (DL1) with escalation to 10 mg/m2 (DL2), 15 mg/m2 (DL3), and 25 mg/m2 (DL4). PI3K/mTOR pathway inhibition was measured by phosphoflow cytometry analysis of peripheral blood specimens from treated patients. Sixteen heavily-pretreated patients were enrolled with 15 evaluable for toxicity. One dose-limiting toxicity of grade 4 pleural and pericardial effusions occurred in a patient treated at DL3. Additional dose-limiting toxicities were not seen in the DL3 expansion or DL4 cohort. Grade 3/4 non-hematologic toxicities occurring in three or more patients included febrile neutropenia, elevated alanine aminotransferase, hypokalemia, mucositis, and tumor lysis syndrome and occurred across all doses. Response and complete were observed at all dose levels with a 47% overall response rate and 27% complete response rate. Pharmacodynamic correlative studies demonstrated dose-dependent inhibition of PI3K/mTOR pathway phosphoproteins in all studied patients. Temsirolimus at doses up to 25 mg/m2 with cyclophosphamide and etoposide had an acceptable safety profile in children with relapsed/refractory ALL. Pharmacodynamic mTOR target inhibition was achieved and appeared to correlate with temsirolimus dose. Future testing of next-generation PI3K/mTOR pathway inhibitors with chemotherapy may be warranted to increase response rates in children with relapsed/refractory ALL.

Novel Treatments for Pediatric Relapsed or Refractory Acute B-Cell Lineage Lymphoblastic Leukemia: Precision Medicine Era

With the markedly increased cure rate for children with newly diagnosed pediatric B-cell acute lymphoblastic leukemia (B-ALL), relapse and refractory B-ALL (R/R B-ALL) remain the primary cause of death worldwide due to the limitations of multidrug chemotherapy. As we now have a more profound understanding of R/R ALL, including the mechanism of recurrence and drug resistance, prognostic indicators, genotypic changes and so on, we can use newly emerging technologies to identify operational molecular targets and find sensitive drugs for individualized treatment. In addition, more promising and innovative immunotherapies and molecular targeted drugs that are expected to kill leukemic cells more effectively while maintaining low toxicity to achieve minimal residual disease (MRD) negativity and better bridge hematopoietic stem cell transplantation (HSCT) have also been widely developed. To date, the prognosis of pediatric patients with R/R B-ALL has been enhanced markedly thanks to the development of novel drugs. This article reviews the new advancements of several promising strategies for pediatric R/R B-ALL.

Outcomes after late bone marrow and very early central nervous system relapse of childhood B-acute lymphoblastic leukemia: a report from the Children's Oncology Group phase III study AALL0433

Outcomes after relapse of childhood B-acute lymphoblastic leukemia (B-ALL) are poor, and optimal therapy is unclear. The children’s Oncology Group study AALL0433 evaluated a new platform for relapsed ALL. Between March 2007 and October 2013 AALL0433 enrolled 275 participants with late bone marrow or very early isolated central nervous system (iCNS) relapse of childhood B-ALL. Patients were randomized to receive standard versus intensive vincristine dosing; this randomization was closed due to excess peripheral neuropathy in 2010. Patients with matched sibling donors received allogeneic hematopoietic cell transplantation (HCT) after the first three blocks of therapy. The prognostic value of minimal residual disease (MRD) was also evaluated in this study. The 3-year event free and overall survival (EFS/OS) for the 271 eligible patients were 63.6±3.0% and 72.3±2.8% respectively. MRD at the end of Induction-1 was highly predictive of outcome, with 3-year EFS/OS of 84.9±4.0% and 93.8±2.7% for patients with MRD <0.1%, versus 53.7±7.8% and 60.6± 7.8% for patients with MRD ≥0.1% (P<0.0001). Patients who received HCT versus chemotherapy alone had an improved 3-year disease-free survival (77.5±6.2% vs. 66.9 + 4.5%, P=0.03) but not OS (81.5±5.8% for HCT vs. 85.8±3.4% for chemotherapy, P=0.46). Patients with early iCNS relapse fared poorly, with a 3-year EFS/OS of 41.4±9.2% and 51.7±9.3%, respectively. Infectious toxicities of the chemotherapy platform were significant. The AALL0433 chemotherapy platform is efficacious for late bone marrow relapse of B-ALL, but with significant toxicities. The MRD threshold of 0.1% at the end of Induction-1 was highly predictive of the outcome. The optimal role for HCT for this patient population remains uncertain. This trial is registered at clinicaltrials.gov (NCT# 00381680).

Early life vincristine fails to prime developing pain pathways

Early life administration of vincristine (VNC), commonly used to treat pediatric leukemia, evokes peripheral neuropathy and mechanical pain hypersensitivity in rats that lasts into adolescence. However, the degree to which VNC-evoked neuropathic pain persists throughout adulthood has yet to be examined. It also remains unclear if pediatric VNC exposure can 'prime' developing nociceptive pathways and thereby exacerbate chronic pain following subsequent trauma later in life. To address these issues, rats received five total doses of VNC (60 μg/kg; or vehicle) on postnatal days (P) 11, 13, 17, 19 and 21 followed by a hindpaw surgical incision during adulthood. In addition, in order to model the clinical scenario where cancer relapse necessitates another round of chemotherapy, separate groups of rats that had been treated with VNC (or vehicle) as neonates were subsequently administered VNC as adults (five injections at 100 μg/kg). Intraepidermal nerve fiber density and baseline mechanical pain sensitivity were similar between the neonatal VNC and vehicle-treated littermate controls at 13-15 weeks of age, suggesting that the peripheral neuropathy, and resulting chronic pain, had resolved by adulthood. Importantly, there was no significant overall effect of early life VNC on the severity of post-operative pain following adult incision. Similarly, prior VNC exposure did not significantly influence the degree of mechanical pain hypersensitivity produced by adult VNC treatment. Collectively, these findings suggest that early life VNC administration does not increase the susceptibility to develop chronic pain as adults.

Agents in Development for Childhood Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common cancer in childhood. Standard chemotherapy has afforded outstanding outcomes for many patients; however, there remain some sub-groups with high-risk features, refractory disease, and patients that  relapse who have a poor prognosis with conventional treatments. Over the past decade, there have been significant advances in newer treatment options, including improved monoclonal antibody therapies, T cell engagers, and chimeric antigen T-cell receptor products, all of which have changed the landscape for patients who relapse. These are now being introduced more frequently and at earlier stages of therapy. We present a brief overview of the biology and etiology of childhood ALL, treatment strategies currently in use, and discuss some newer strategies and their possible role in the future of ALL therapy for children.

A phase 1 trial of temsirolimus and intensive re-induction chemotherapy for 2nd or greater relapse of acute lymphoblastic leukaemia: a Children's Oncology Group study (ADVL1114)

The phosphatidylinositol 3-kinase (PI3K)/mammalian (or mechanistic) target of rapamycin (mTOR) signalling pathway is commonly dysregulated in acute lymphoblastic leukaemia (ALL). A phase 1 trial of the mTOR inhibitor temsirolimus in combination with UKALL R3 re-induction chemotherapy was conducted in children and adolescents with second or greater relapse of ALL. The initial temsirolimus dose level (DL1) was 10 mg/m² weekly × 3 doses. Subsequent patient cohorts received temsirolimus 7·5 mg/m² weekly × 3 doses (DL0) or, secondary to toxicity, 7·5 mg/m² weekly × 2 doses (DL-1). Sixteen patients were enrolled, 15 were evaluable for toxicity. Dose-limiting toxicity (DLT) occurred at all three dose levels and included hypertriglyceridaemia, mucositis, ulceration, hypertension with reversible posterior leucoencephalopathy, elevated gamma-glutamyltransferase or alkaline phosphatase and sepsis. The addition of temsirolimus to UKALL R3 re-induction therapy resulted in excessive toxicity and was not tolerable in children with relapsed ALL. However, this regimen induced remission in seven of fifteen patients. Three patients had minimal residual disease levels <0·01%. Inhibition of PI3K signalling was detected in patients treated at all dose levels of temsirolimus, but inhibition at an early time point did not appear to correlate with clinical responses at the end of re-induction therapy.

Off-therapy procedures are not beneficial in pediatric B-cell acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. Although curable, approximately 20% of patients relapse. In an effort to detect relapse earlier, our institution performed surveillance bone marrow (BM) and cerebrospinal fluid (CSF) evaluations every 3 months from the end of therapy to 1 year off. This study retrospectively reviewed all patients with B-cell ALL (B-ALL) from September 2005 to September 2010 to determine the benefit and cost of these procedures. Forty-one patients completed therapy and had 190 BMs and 190 lumbar punctures (LPs) performed. Four of 41 patients (9.8%) experienced a relapse. Relapse was detected in only 1 patient by routine BM evaluation (0.5%). Zero LPs were positive. The professional fees for the procedures were $8,738/patient. Therefore, off-therapy BM and CSF evaluations are not effective at detecting relapse and are expensive. Our institution has abandoned off-therapy surveillance for ALL.

Aberrant Notch Signaling in the Bone Marrow Microenvironment of Acute Lymphoid Leukemia Suppresses Osteoblast-Mediated Support of Hematopoietic Niche Function

More than half of T-cell acute lymphoblastic leukemia (T-ALL) patients harbor gain-of-function mutations in the intracellular domain of Notch1. Diffuse infiltration of the bone marrow commonly occurs in T-ALL and relapsed B-cell acute lymphoblastic leukemia patients, and is associated with worse prognosis. However, the mechanism of leukemia outgrowth in the marrow and the resulting biologic impact on hematopoiesis are poorly understood. Here, we investigated targetable cellular and molecular abnormalities in leukemia marrow stroma responsible for the suppression of normal hematopoiesis using a T-ALL mouse model and human T-ALL xenografts. We found that actively proliferating leukemia cells inhibited normal hematopoietic stem and progenitor cell (HSPC) proliferation and homing to the perivascular region. In addition, leukemia development was accompanied by the suppression of the endosteum-lining osteoblast population. We further demonstrated that aberrant Notch activation in the stroma plays an important role in negatively regulating the expression of CXLC12 on osteoblasts and their differentiation. Notch blockade reversed attenuated HSPC cycling, leukemia-associated abnormal blood lineage distribution, and thrombocytopenia as well as recovered osteoblast and HSPC abundance and improved the hematopoietic-supportive functions of osteoblasts. Finally, we confirmed that reduced osteoblast frequency and enhanced Notch signaling were also features of the marrow stroma of human ALL tissues. Collectively, our findings suggest that therapeutically targeting the leukemia-infiltrated hematopoietic niche may restore HSPC homeostasis and improve the outcome of ALL patients.

The role of 18F-FDG PET/CT in pediatric lymph-node acute lymphoblastic leukemia involvement

In pediatric oncology, positron emission tomography/computed tomography (PET/CT) is emerging as an essential diagnostic tool in characterizing suspicious neoplastic lesions and staging malignant diseases. Most studies regarding the possible role of FDG-PET/CT in the management of acute lymphoblastic leukemia (ALL) patients are limited to adults. Here we report a pediatric patient with recurrent ALL, in which FDG-PET/CT was used both to define more precisely the cause of lymphadenopathy and to assess the effect of the second-line therapy.

Chemokines and relapses in childhood acute lymphoblastic leukemia: A role in migration and in resistance to antileukemic drugs

We studied whether chemokines may have a role in relapses in childhood acute lymphoblastic leukemia (ALL). We compared the levels of chemokine receptors in marrow samples from 82 children with ALL at diagnosis versus 15 at relapses, and quantified the levels of chemokines in central system fluid (CSF) samples. The functional role of specific chemokines was studied in vitro and in vivo. The expression of some chemokine receptors was upregulated upon leukemic relapse, both in B- and in T-ALL, and in cases of medullary and extramedullary involvement. CXCL10 induced chemotaxis in leukemic cell lines and in primary leukemic cells, depending upon the levels of CXCR3 expression. CXCL10 specifically diminished chemotherapy-induced apoptosis on ALL cells expressing CXCR3, partially inhibiting caspase activation and maintaining the levels of the antiapoptotic protein Bcl-2. Finally, immunodeficient mice engrafted with CXCR3-expressing human leukemic cells showed decreased infiltration of marrow, spleen, and CNS after receiving a CXCR3-antagonist molecule. CXCR3 signaling in ALL may have a dual function: chemotactic for the localisation of leukemic blasts in specific niches, and it may also confer resistance to chemotherapy, enhancing the chances for relapses.

Treatment of pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric oncologic diagnosis, and advances in its treatment have led to progressive improvements in survival. The 4 main components of therapy are remission induction, consolidation, maintenance, and central nervous system-directed therapy, and usually last 2 to 3 years. Treatment intensity based on risk-based stratification is the cornerstone of treatment. Patients with features of more favorable disease are spared the more toxic effects of chemotherapy, whereas more aggressive regimens are reserved for those with higher-risk disease. Prognosis of relapsed pediatric ALL depends primarily on duration of remission and site of relapse.

T-cell lymphoblastic leukemia/lymphoma: relapse 16 years after first remission

Little information is available regarding late relapse in patients with T-lymphoblastic leukemia/lymphoma (T-LBL). Because of the aggressive nature of this disease, relapse is common and often happens early. Late relapses are rare and generally occur within a few years after initial remission. The relapse rate after 3 years has been reported to steadily decrease over time yet does not parallel with cure. We report a case of a 26-year-old female with T-LBL and relapse 16 years after her first remission with successful treatment with HyperCVAD and L-asparaginase.

Clonal selection and therapy resistance in acute leukaemias: mathematical modelling explains different proliferation patterns at diagnosis and relapse

Recent experimental evidence suggests that acute myeloid leukaemias may originate from multiple clones of malignant cells. Nevertheless, it is not known how the observed clones may differ with respect to cell properties, such as proliferation and self-renewal. There are scarcely any data on how these cell properties change due to chemotherapy and relapse. We propose a new mathematical model to investigate the impact of cell properties on the multi-clonal composition of leukaemias. Model results imply that enhanced self-renewal may be a key mechanism in the clonal selection process. Simulations suggest that fast proliferating and highly self-renewing cells dominate at primary diagnosis, while relapse following therapy-induced remission is triggered mostly by highly self-renewing but slowly proliferating cells. Comparison of simulation results to patient data demonstrates that the proposed model is consistent with clinically observed dynamics based on a clonal selection process.

Survival differences between adolescents/young adults and children with B precursor acute lymphoblastic leukemia after allogeneic hematopoietic cell transplantation

Risk-adapted therapy has been the cornerstone of treatment for pediatric B precursor acute lymphoblastic leukemia (B-ALL). Recently, age ≥ 13 years at diagnosis has been identified as a very high-risk feature for chemotherapy treated pediatric patients with B-ALL. Whether age at time of transplantation is associated with poor outcomes in adolescents and young adults (AYA) is unknown. We hypothesized that AYA receiving allogeneic hematopoietic cell transplantation (allo-HCT) would have greater relapse and inferior survival compared with children age <13 years. We reviewed the outcomes in 136 consecutive patients (age 0-30 years) with B-ALL who underwent myeloablative allo-HCT at our institution, including 79 children age <13 years (58%) and 57 AYA age 13-30 years (42%). Overall survival at 5 years was significantly lower in the AYA group (hazard ratio, 1.74; 95% confidence interval [CI], 1.04-2.95; P = .03). In addition, the AYA patients had a greater risk of transplantation-related mortality at 1 year (hazard ratio, 2.23; 95% CI, 1.01-4.90; P = .05), but no difference in relapse (relative risk, 0.85; 95% CI, 0.41-1.76; P = .66). Based on this analysis, AYA patients undergoing allo-HCT for B-ALL have significantly inferior survival and greater transplantation-related mortality compared with children age <13 years, but no difference in relapse, suggesting that allo-HCT may overcome relapse in AYA. Further improvements in peritransplantation care are needed to limit complications in AYA patients.

Outcome after first relapse in children with acute lymphoblastic leukemia: a report based on the Dutch Childhood Oncology Group (DCOG) relapse all 98 protocol

BACKGROUND

We report on the treatment of children and adolescents with acute lymphoblastic leukemia (ALL) in first relapse. The protocol focused on: (1) Intensive chemotherapy preceding allogeneic stem cell transplantation (SCT) in early bone marrow relapse; (2) Rotational chemotherapy in late relapse, without donor; (3) Postponement of cerebro-spinal irradiation in late isolated CNS relapse; and (4) Treatment in very late bone marrow relapse with chemotherapy only.

METHODS

From January 1999 until July 2006 all 158 Dutch pediatric patients with ALL in first relapse were recorded. Ninety-nine patients were eligible; 54 patients with early and 45 with late relapse. Eighteen patients had an isolated extra-medullary relapse; 69 patients had bone marrow involvement only.

RESULTS

Five-years EFS rates for early and late relapses were 12% and 35%, respectively. For early relapses 5 years EFSs were 25% for patients transplanted; 0% for non-transplanted patients. For late relapses 5 years EFS was 64% for patients treated with chemotherapy only, and 16% for transplanted patients. For very late relapses EFS was 58%.

CONCLUSIONS

Our data suggest the superiority of SCT for early relapse patients. For late relapses a better outcome is achieved with chemotherapy only using the rotational chemotherapy scheme. The most important factor for survival was interval between first CR and occurrence of the first relapse.

Treating refractory leukemias in childhood, role of clofarabine

Approximately 4000 children and adolescents under the age of 20 years develop acute leukemia per year in the US. Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer. Despite impressive improvements in outcome, relapsed ALL is the fourth most common pediatric malignancy. Therapy for relapsed ALL remains unsatisfactory, and the majority of relapse patients still succumb to leukemia. Between one-third and one-half of patients with acute myelogenous leukemia (AML) relapse, and no standard therapy is recognized for patients with relapsed and/or refractory AML. Novel therapeutic agents are needed to improve the cure rate for relapsed ALL and AML. Clofarabine is a next-generation nucleoside analog, designed to incorporate the best features and improve the therapeutic index of cladribine and fludarabine. Clofarabine inhibits both DNA polymerase and ribonucleotide reductase, leading to impaired DNA synthesis and repair, and directly induces apoptosis. Phase I and II single-agent trials in children have shown that clofarabine is safe and active in both myeloid and lymphoid relapsed/refractory acute leukemias. Clofarabine has been approved by the FDA for pediatric patients with relapsed/refractory ALL after at least 2 prior therapeutic attempts. Rational combinations of clofarabine with other active agents in refractory leukemias are currently under investigation.

Clonal origins of relapse in ETV6-RUNX1 acute lymphoblastic leukemia

B-cell precursor childhood acute lymphoblastic leukemia with ETV6-RUNX1 (TEL-AML1) fusion has an overall good prognosis, but relapses occur, usually after cessation of treatment and occasionally many years later. We have investigated the clonal origins of relapse by comparing the profiles of genomewide copy number alterations at presentation in 21 patients with those in matched relapse (12-119 months). We identified, in total, 159 copy number alterations at presentation and 231 at relapse (excluding Ig/TCR). Deletions of CDKN2A/B or CCNC (6q16.2-3) or both increased from 38% at presentation to 76% in relapse, suggesting that cell-cycle deregulation contributed to emergence of relapse. A novel observation was recurrent gain of chromosome 16 (2 patients at presentation, 4 at relapse) and deletion of plasmocytoma variant translocation 1 in 3 patients. The data indicate that, irrespective of time to relapse, the relapse clone was derived from either a major or minor clone at presentation. Backtracking analysis by FISH identified a minor subclone at diagnosis whose genotype matched that observed in relapse ∼ 10 years later. These data indicate subclonal diversity at diagnosis, providing a variable basis for intraclonal origins of relapse and extended periods (years) of dormancy, possibly by quiescence, for stem cells in ETV6-RUNX1(+) acute lymphoblastic leukemia.

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.

Improved outcome in childhood ALL with intensive consolidation and hematopoietic stem cell transplant

Background

Despite advances in chemotherapy, the prognosis of relapsed acute lymphoblastic leukemia (ALL) remains poor. Few studies on relapsed ALL have reported the importance of intensive consolidation followed with or without allogeneic hematopoietic stem cell transplantation (HSCT).

Methods

We evaluated the post-relapse outcomes in 47 Korean children with a first marrow relapse, and analyzed the prognostic factors.

Results

A second complete remission (CR) was achieved in 40 patients (85.1%), and at the time of this study, second CR was maintained in 12 of these patients. The estimated 3-yr event-free survival (EFS) rate after the first marrow relapse was 29.8±6.7%, and the overall survival (OS) rate was 45.3±7.5%. We found that second remission, consolidation of pediatric oncology group chemotherapy regimen (POG 9411), and HSCT significantly affected the outcome of the disease after relapse (P<0.001; P=0.004; P=0.05).

Conclusion

The results of our study revealed that an intensified POG 9411 consolidation chemotherapy regimen followed by HSCT can improve the outcome of patients with relapsed ALL.

Vandetanib mediates anti-leukemia activity by multiple mechanisms and interacts synergistically with DNA damaging agents

Vandetanib is an orally active small molecule tyrosine kinase inhibitor (TKI) with activity against several pathways implicated in malignancy including the vascular endothelial growth factor receptor pathway, the epidermal growth factor receptor pathway, the platelet derived growth factor receptor β pathway, and REarranged during Transfection pathway. To determine if vandetanib-mediated inhibition of receptor tyrosine kinases is a potential therapeutic strategy for pediatric acute leukemia, these studies aimed to characterize the activity of vandetanib against acute leukemia in vitro. Treatment of leukemia cell lines with vandetanib resulted in a dose-dependent decrease in proliferation and survival. Vandetanib's anti-leukemic activity appeared mediated by multiple mechanisms including accumulation in G1 phase at lower concentrations and apoptosis at higher concentrations. Alterations in cell surface markers also occurred with vandetanib treatment, suggesting induction of differentiation. In combination with DNA damaging agents (etoposide and doxorubicin) vandetanib demonstrated synergistic induction of cell death. However in combination with the anti-metabolite methotrexate, vandetanib had an antagonistic effect on cell death. Although several targets of vandetanib are expressed on acute leukemia cell lines, expression of vandetanib targets did not predict vandetanib sensitivity and alone are therefore not likely candidate biomarkers in patients with acute leukemia. Interactions between vandetanib and standard chemotherapy agents in vitro may help guide choice of combination regimens for further evaluation in the clinical setting for patients with relapsed/refractory acute leukemia. Taken together, these preclinical data support clinical evaluation of vandetanib, in combination with cytotoxic chemotherapy, for pediatric leukemia.

Use of recombinant cell-permeable small peptides to modulate glucocorticoid sensitivity of acute lymphoblastic leukemia cells

Glucocorticoid (GC) hormones induce apoptosis in T-cell and pre-B-cell acute lymphoblastic leukemia (ALL) cells. Steroid-mediated apoptosis requires a threshold level of the glucocorticoid receptor (GR) protein, and increasing the intracellular GR levels in ALL cells would augment their hormone sensitivity. A protein transduction domain (PTD) approach was used to accomplish this. We produced an HIV Tat PTD domain fusion protein (Tat-GR(554-777)) that potentially competes for the degradation of GR protein by the ubiquitin-proteasome system and should thus increase its intracellular levels by "stabilizing" the GR. We also designed a fusion peptide for the c-Myb DNA binding domain, Tat-c-Myb DBD, since the biological function of this peptide as a dominant negative inhibitor of the c-Myb protein was already known. Purified, bacterially expressed Tat-c-Myb DBD and Tat-GR(554-777) exhibited highly efficient transduction into cultured ALL cell lines including 697 (pre-B-ALL) and CEM-C7 (T-ALL) cells. As expected, the transduced Tat-c-Myb DBD peptide inhibited steroid-mediated stimulation of a GR promoter-luciferase reporter gene. Significantly, transduced Tat-GR(554-777) effectively increased intracellular GR levels in the GC-resistant T-ALL cell line, CEM-C1, and in the pre-B-ALL 697 cell line. Furthermore, transduction of Tat-GR(554-777) rendered GC-resistant CEM-C1 cells sensitive to steroid killing and further sensitized 697 cells to steroid. The use of Tat-fusion peptide transduction may eventually lead to innovative therapeutic modalities to improve the clinical response of patients suffering from T-cell and pre-B-cell acute lymphoblastic leukemia by increasing steroid responsiveness and perhaps converting steroid-resistant leukemia to a hormone-responsive phenotype.

Isolated gut relapse presenting as chronic diarrhea during maintenance therapy for acute lymphoblastic leukemia

Ten-year-old boy with acute lymphoblastic leukemia (ALL)-T cell subtype was on MRC UKALL 2003-based chemotherapy. Bone marrow attained remission after induction. After 8 months into maintenance, he presented with chronic diarrhea and weight loss. Search for infective and malabsorptive etiology was unrewarding. Infiltration with leukemic cells was seen in the lamina propria on mucosal biopsies of duodenum and colon. Marrow was in remission. Isolated gut relapse is exceedingly rare. It should be considered in the etiology of chronic diarrhea in patients with ALL, after common causes are excluded.

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.

zeta-Crystallin is a bcl-2 mRNA binding protein involved in bcl-2 overexpression in T-cell acute lymphocytic leukemia

The human antiapoptotic bcl-2 gene has been discovered in t(14;18) B-cell leukemias/lymphomas because of its overexpression caused at a transcriptional control level by the bcl-2/IgH fusion gene. We were the first to disclose the post-transcriptional control of bcl-2 expression mediated by interactions of an adenine + uracil (AU)-rich element (ARE) in the 3'-UTR of bcl-2 mRNA with AU-binding proteins (AUBPs). Here, we identify and characterize zeta-crystallin as a new bcl-2 AUBP, whose silencing or overexpression has impact on bcl-2 mRNA stability. An increased Bcl-2 level observed in normal phytohemagglutinin (PHA)-activated T lymphocytes, acute lymphatic leukemia (ALL) T-cell lines, and T cells of patients with leukemia in comparison with normal non-PHA-activated T lymphocytes was concomitant with an increase in zeta-crystallin level. The specific association of zeta-crystallin with the bcl-2 ARE was significantly enhanced in T cells of patients with ALL, which accounts for the higher stability of bcl-2 mRNA and suggests a possible contribution of zeta-crystallin to bcl-2 overexpression occurring in this leukemia.

Outcome of patients treated for relapsed or refractory acute lymphoblastic leukemia: a Therapeutic Advances in Childhood Leukemia Consortium study

PURPOSE

Despite improvements in treatment, approximately 20% of patients with acute lymphoblastic leukemia (ALL) experience relapse and do poorly. The Therapeutic Advances in Childhood Leukemia (TACL) Consortium was assembled to assess novel drugs for children with resistant leukemia. We hypothesize that novel agents and combinations that fail to improve baseline complete remission rates in comparable populations are unlikely to contribute to better outcomes and should be abandoned. We sought to define response rates and disease-free survival (DFS) rates in patients treated at TACL institutions, which could serve as a comparator for future studies.

PATIENTS AND METHODS

We performed a retrospective cohort review of patients with relapsed and refractory ALL previously treated at TACL institutions between the years of 1995 and 2004. Data regarding initial and relapsed disease characteristics, disease response, and survival were collected and compared with those of published reports.

RESULTS

Complete remission (CR) rates (mean +/- SE) were 83% +/- 4% for early first marrow relapse, 93% +/- 3% for late first marrow relapse, 44% +/- 5% for second marrow relapse, and 27% +/- 6% for third marrow relapse. Five-year DFS rates in CR2 and CR3 were 27% +/- 4% and 15% +/- 7% respectively.

CONCLUSION

We generally confirm a 40% CR rate for second and subsequent relapse, but our remission rate for early first relapse seems better than that reported in the literature (83% v approximately 70%). Our data may allow useful modeling of an expected remission rate for any population of patients who experience relapse.

Unrelated hematopoietic stem cell transplantation for children with acute leukemia: experience at a single institution

We evaluate the outcomes in children with acute leukemia who received allogeneic hematopoietic stem cell transplantation (HCT) using unrelated donor. Fifty-six children in complete remission (CR) received HCT from unrelated donors between 2000 and 2007. Thirty-five had acute myeloid leukemia, and 21 had acute lymphoid leukemia. Stem cell sources included bone marrow in 38, peripheral blood in 4, and cord blood (CB) in 14. Four patients died before engraftment and 52 engrafted. Twenty patients developed grade II-IV acute graft-versus-host disease (GVHD) and 8 developed extensive chronic GVHD. With median follow-up of 39.1 months, event free survival and overall survival were 60.4% and 67.5%, respectively, at 5 yr. Events included relapse in 10 and treatment-related mortality (TRM) in 10. The causes of TRM included sepsis in 4, GVHD in 4 (1 acute GVHD and 3 chronic GVHD), veno-occlusive disease in 1 and fulminant hepatitis in 1. Patients transplanted with CB had event free survival of 57.1%, comparable to 63.2% for those transplanted with other than CB. In conclusion, HCT with unrelated donors is effective treatment modality for children with acute leukemia. In children with acute leukemia candidate for HCT but lack suitable sibling donor, unrelated HCT may be a possible treatment option at the adequate time of their disease.

Improvement of induction remission rate by modifying the dose of idarubicin for relapsed childhood acute lymphoblastic leukemia

Relapse is the major cause of treatment failure in acute lymphoblastic leukemia (ALL), yet there is no established treatment for relapsed ALL. To improve the induction remission rate, we modified the dose of idarubicin in the original Children's Cancer Group (CCG)-1884 protocol, and retrospectively compared the results. Twenty-eight patients diagnosed with relapsed ALL received induction chemotherapy according to the CCG-1884 protocol. Complete remission (CR) rate in all patients after induction chemotherapy was 57%. The idarubicin 10 mg/m(2)/week group showed CR rate of 74%, compared with the 22% CR rate of the idarubicin 12.5 mg/m(2)/week group (p=0.010). Remission failure due to treatment-related mortality (TRM) was 44% and 5.2% in the idarubicin 12.5 mg/m(2)/week and 10 mg/m(2)/week groups, respectively (p=0.011). Overall survival (OS) and 4-yr event-free survival (EFS) were 12.8% and 10.3%, respectively. OS and 4-yr EFS were higher in the idarubicin 10 mg/m(2)/week group (19.3% and 15.6%) than in the 12.5 mg/m(2)/week group (0% and 0%). In conclusion, a modified dose of idarubicin from 12.5 mg/m(2)/week to 10 mg/m(2)/week resulted in an improved CR rate in the treatment of relapsed ALL, which was due to lower TRM. However, despite improved CR rate with modified dose of idarubicin, survival rates were unsatisfactory.

Novel molecular and cellular therapeutic targets in acute lymphoblastic leukemia and lymphoproliferative disease

While the outcome for pediatric patients with lymphoproliferative disorders (LPD) or lymphoid malignancies, such as acute lymphoblastic leukemia (ALL), has improved dramatically, patients often suffer from therapeutic sequelae. Additionally, despite intensified treatment, the prognosis remains dismal for patients with refractory or relapsed disease. Thus, novel biologically targeted treatment approaches are needed. These targets can be identified by understanding how a loss of lymphocyte homeostasis can result in LPD or ALL. Herein, we review potential molecular and cellular therapeutic strategies that (i) target key signaling networks (e.g., PI3K/AKT/mTOR, JAK/STAT, Notch1, and SRC kinase family-containing pathways) which regulate lymphocyte growth, survival, and function; (ii) block the interaction of ALL cells with stromal cells or lymphoid growth factors secreted by the bone marrow microenvironment; or (iii) stimulate innate and adaptive immune responses.

Novel semisynthetic triterpenoid AMR-Me inhibits telomerase activity in human leukemic CEM cells and exhibits in vivo antitumor activity against Dalton's lymphoma ascites tumor

Telomerase, a ribonucleoprotein complex of hTERT and hTER, has been reported to be associated with carcinogenesis and multidrug resistance (MDR). Methyl-25-hydroxy-3-oxoolean-12-en-28-oate (AMR-Me) is a novel semisynthetic triterpenoid, derived from a triterpene acid isolated from the stem bark of a tropical tree Amoora rohituka grown wild in India. We examined the role of telomerase in mediating the growth suppression of human acute lymphoblastic leukemic CEM cells by AMR-Me. The results showed that AMR-Me inhibited the growth and viability of CEM cells, induced apoptosis and cell cycle arrest in G(2)+M phase. AMR-Me treatment resulted in suppression of hTERT expression and a concomitant inhibition of telomerase activity. The in vivo antitumor activity of AMR-Me was determined using mice inoculated with Dalton's lymphoma ascites tumor cells. Intraperitoneal administration of the AMR-Me at doses of 1 or 3mg/kg, increased the survival rate by 121% and 133% respectively, without weight change over the treatment period. Our results suggest that AMR-Me inhibits telomerase activity by decreasing the hTERT expression and induces apoptosis in human lymphoblastic leukemic CEM cells, thus providing the molecular basis for the development of AMR-Me as a novel chemotherapeutic agent against leukemia.

Factors influencing survival after relapse from acute lymphoblastic leukemia: a Children's Oncology Group study

Despite great progress in curing childhood acute lymphoblastic leukemia (ALL), survival after relapse remains poor. We analyzed survival after relapse among 9585 pediatric patients enrolled on Children's Oncology Group clinical trials between 1988 and 2002. A total of 1961 patients (20.5%) experienced relapse at any site. The primary end point was survival. Patients were subcategorized by the site of relapse and timing of relapse from initial diagnosis. Time to relapse remains the strongest predictor of survival. Patients experiencing early relapse less than 18 months from initial diagnosis had a particularly poor outcome with a 5-year survival estimate of 21.0+/-1.8%. Standard risk patients who relapsed had improved survival compared with their higher risk counterparts; differences in survival for the two risk groups was most pronounced for patients relapsing after 18 months. Adjusting for both time and relapse site, multivariate analysis showed that age (10+ years) and the presence of central nervous system disease at diagnosis, male gender, and T-cell disease were significant predictors of inferior post-relapse survival. It can be noted that there was no difference in survival rates for relapsed patients in earlier vs later era trials. New therapeutic strategies are urgently needed for children with relapsed ALL and efforts should focus on discovering the biological pathways that mediate drug resistance.

Prediction of relapse in paediatric pre-B acute lymphoblastic leukaemia using a three-gene risk index

Despite high cure rates 25% of children with acute lymphoblastic leukaemia (ALL) relapse and have dismal outcome. Crucially, many are currently stratified as standard risk (SR) and additional markers to improve patient stratification are required. Here we have used diagnostic bone marrow specimens from 101 children with pre-B ALL to examine the use of gene expression profiles (GEP) as predictors of long-term clinical outcome. Patients were divided into two cohorts for model development and validation based on availability of specimen material. Initially, GEP from 55 patients with sufficient material were analysed using HG-U133A microarrays, identifying an 18-gene classifier (GC) that was more predictive of outcome than conventional prognostic parameters. After feature selection and validation of expression levels by quantitative reverse transcription polymerase chain reaction (qRT-PCR), a three-gene qRT-PCR risk index [glutamine synthetase (GLUL), ornithine decarboxylase antizyme inhibitor (AZIN), immunoglobulin J chain (IGJ)] was developed that predicted outcome with an accuracy of 89% in the array cohort and 87% in the independent validation cohort. The data demonstrate the feasibility of using GEP to improve risk stratification in childhood ALL. This is particularly important for the identification of patients destined to relapse despite their current stratification as SR, as more intensive front-line treatment options for these individuals are already available.

Phase II study of topotecan in combination with dexamethasone, asparaginase, and vincristine in pediatric patients with acute lymphoblastic leukemia in first relapse

BACKGROUND

The authors evaluated the response rate, toxicity, and pharmacokinetics of topotecan given before standard induction therapy for childhood acute lymphoblastic leukemia (ALL) in first relapse.

METHODS

Patients received topotecan (2.4 mg/m(2) daily as a 30-minute infusion) for 5 days before induction therapy with dexamethasone, vincristine, and asparaginase (native or pegylated Escherichia coli). The pharmacokinetics of topotecan were measured with the first dose of treatment in 23 patients.

RESULTS

Twenty-eight of 31 patients with circulating blast cells were evaluable for response to topotecan. Twenty-five patients (89.3%) had a response (>25% decrease in circulating blast cells). The leukocyte count (P = .0001) and blast cell count (P = .0009) declined significantly during topotecan therapy. The median (range) topotecan lactone area under the concentration-time curve after the first dose was 85.4 L/hour/m(2) (range, 38.7-229.3 L/hour/m(2)). At the end of induction, 23 patients (74.2%) had a complete response, 1 patient (3.2%) had a partial response, 5 patients (16.1%) had no response, and 2 patients had died of infection. Six of the 17 patients who were studied for minimal residual disease (MRD) achieved MRD-negative status at the end of induction. The main toxicities were hematologic, gastrointestinal, and hepatic. The estimated 5-year survival rate, event-free survival rate, and cumulative incidence of second relapse were 24.1% +/- 7.9%, 18.2% +/- 7.4%, and 22.8% +/- 8.7%, respectively, in the 29 patients who had a hematologic first relapse.

CONCLUSIONS

A regimen comprising single-agent topotecan given with a standard 3-drug combination was effective in inducing remission in pediatric patients with relapsed ALL and was tolerated well.

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.

Submicroscopic bone marrow involvement in isolated extramedullary relapses in childhood acute lymphoblastic leukemia: a more precise definition of “isolated” and its possible clinical implications, a collaborative study of the Resistant Disease Committee of the International BFM study group

This study investigates the extent of bone marrow (BM) involvement at diagnosis of apparent isolated extramedullary (AIEM) relapses of childhood acute lymphoblastic leukemia (ALL) and its relation to prognosis. Sixty-four children with first AIEM relapse treated in Germany, Czech Republic, or France were included. Real-time quantitative polymerase chain reaction using T-cell receptor and immunoglobulin gene rearrangements provided a sensitive measure of submicroscopic BM involvement, which was detectable at a level of 10−4 or higher in 46 patients and less than 10−4 in 11 patients, and was nondetectable (sensitivity: 10−4) in 7 patients. In the total cohort, the probability of event-free survival (pEFS) for children with BM involvement of 10−4 or higher was 0.30 (0.09 ± SE) versus 0.60 (± 0.12) for those with less than 10−4 (P = .13). The cumulative incidence of subsequent relapse was 0.24 (± 0.01) for patients with BM involvement less than 10−4 and 0.65 (± 0.01) for those with 10−4 or higher (P = .012). Restricted to central nervous system (CNS) relapses, pEFS was 0.11 (± 0.09) for patients with BM involvement 10−4 or higher and 0.63 (± 0.17) for those with less than 10−4 (P = .053). CNS relapses were associated with a higher (≥ 10−4: 80%) submicroscopic BM involvement than testicular relapses (≥ 10−4: 57%, P = .08). In summary, we show marked heterogeneity of submicroscopic BM involvement at first AIEM relapse diagnosis in children with ALL, and demonstrate its possible prognostic relevance.

Acute sciatica: an unusual presentation of extramedullary relapse of acute lymphoblastic leukemia

A 10-year-old boy who had been treated for acute lymphoblastic leukemia presented with persistent numbness of the left big toe and progressive pain of the ipsilateral lower leg. He had received allogeneic bone marrow transplantation 3 months after a testicular relapse. He was in hematologic remission at admission but as progressive swelling of his left leg continued, bone marrow relapse developed. A muscle biopsy revealed leukemic infiltrates in the surrounding muscles of the left sciatic nerve, and swelling of the nerve was found on a magnetic resonance imaging scan. His symptoms/signs subsided soon after reinduction chemotherapy. Unfortunately, he didn't survive because of a fungal sepsis that developed during the neutropenic state. This case represents a rare neurologic complication of what is currently an uncommon presentation for relapse of acute lymphoblastic leukemia, with acute sciatica and without coexisting epidural or leptomeningeal leukemia.

Survival following relapse in childhood haematological malignancies diagnosed in 1974-2003 in Yorkshire, UK

We examined population-based information on relapsed childhood haematological cancers, investigating factors that might influence both overall survival and survival following relapse among the 1177 children (0-14 years) diagnosed with a haematological malignancy in Yorkshire from 1974 to 2003, of whom 342 (29%) relapsed at least once. Leukaemia patients from more deprived areas were significantly less likely to relapse (odds ratio=0.54, 95% confidence interval 0.32-0.93 for most deprived quintile vs least deprived quintile; P(trend)=0.06), especially those with acute myeloid leukaemia (P=0.04). Neither ethnic group nor distance to the main treatment centre was associated with risk of relapse. Overall, patients who relapsed at least once had 5-year survival rates of 46% (41-51%) compared with 79% (76-81%) of those who did not. Five-year survival rates from the time of first relapse increased from 20% in 1974-1983 to 45% in 1984-2003. Length of first remission was a strong predictor of survival for leukaemia with a 46% reduced risk of death for every additional year of event-free survival. Of children who experienced a relapse, 46% survived at least 5 years, whereas just under half of patients survived 5 years beyond disease recurrence. This provides a baseline for future comparisons and demonstrates that relapsed childhood cancer need not imply a poor outcome.

Combinations of the FLT3 inhibitor CEP-701 and chemotherapy synergistically kill infant and childhood MLL-rearranged ALL cells in a sequence-dependent manner

Mixed lineage leukemia (MLL) rearrangements occur in 80% of infants and 5% of older children with acute lymphoblastic leukemia (ALL). These cases have a poor prognosis with current therapy. The FLT3 kinase is overexpressed and constitutively activated in MLL-rearranged ALL cells. The FLT3 inhibitor CEP-701 selectively kills these cells, but is unlikely to be curative if used as monotherapy. To identify potentially synergistic combination strategies, we studied CEP-701 and six standard chemotherapeutic agents in three sequences of exposure (S1: chemotherapy followed by CEP-701, S2: simultaneous exposure to both; and S3: CEP-701 followed by chemotherapy) using MLL-rearranged ALL cell lines and patient bone marrow samples. MTT cytotoxicity and annexin V binding apoptosis assays were used to assess antileukemic effects. Combination indices (CI) were calculated for each combination (CI<0.9 - synergistic; CI 0.9-1.1 - additive; CI>1.1 - antagonistic). A striking pattern of sequence-dependent synergy was observed: S1 was markedly synergistic (mean CI=0.59+/-0.10), S2 was additive (mean CI=0.99+/-0.09) and S3 was antagonistic (mean CI=1.23+/-0.10). The sequence dependence is attributable to the effect of CEP-701 on cell cycle kinetics, and is mediated specifically by FLT3 inhibition, as these effects are not seen in control cells without activated FLT3.

Allogeneic stem cell transplantation in children with acute lymphoblastic leukemia after isolated central nervous system relapse: our experiences and review of the literature

The prognosis of patients with acute lymphoblastic leukemia (ALL) and central nervous system (CNS) relapse has historically been very poor. Although chemo-radiotherapy has improved outcomes, some patients still have a poor prognosis after CNS relapse. Therefore, allogeneic hematopoietic stem cell transplantation (allo-SCT) has recently become an option for treatment of CNS leukemia; however, information, particularly on the long-term outcome of transplant recipients, is limited. We performed allo-SCT in eight pediatric patients with ALL (n=7) or T-cell type non-Hodgkin's lymphoma (n=1), who had isolated CNS relapse. All patients survived for a median of 70.5 (range, 13-153) months after SCT. Sequelae developed late in some patients: mental retardation (IQ=47) in one patient, severe alopecia in two patients, limited chronic graft-versus-host-disease in three patients, and amenorrhea and/or hypothyroidism in three patients. Except for a pre-school child with post transplant CNS relapse, six out of seven patients show normal school/social performance. Our results clearly indicate a high cure rate of isolated CNS relapse by allo-SCT in pediatric lymphoid malignancies; however, there needs to be further studies to determine which are the appropriate candidates for transplantation and what is the best transplant regimen to achieve high cure rate and maintain good quality of life.

Hematopoietic stem cell transplantation after first marrow relapse of non-T, non-B acute lymphoblastic leukemia: a pediatric oncology group pilot feasibility study

BACKGROUND

Relapsed acute lymphoblastic leukemia (ALL) in children is associated with a poor outcome, especially for those patients whose relapse occurs during the first 36 months after diagnosis. The best therapy for these patients is not known. This study was designed to evaluate the feasibility of enrolling children with recurrent ALL in a standardized treatment protocol that included receipt of a hematopoietic stem cell transplant (HSCT).

PROCEDURE

Eligible patients with a bone marrow relapse of non-T, non-B ALL underwent a common induction and consolidation followed by receipt of either an allogeneic HSCT from a human leukocyte antigen (HLA)-identical sibling or an autologous HSCT purged with B-4 blocked ricin. A common conditioning regimen was used for all patients.

RESULTS

Twenty-eight patients from eight institutions were enrolled. Fourteen patients did not receive a transplant during the study, because of toxicity (4), relapse (1), inadequate purging (1), and parental or physician preference for an alternative donor transplant (8). Six patients received allogeneic HSCTs. Five of them have remained in remission for a median of 78 months. Eight patients received autologous HSCTs purged with B4-blocked ricin. Four have remained in remission for a median of 94 months. Of the nine patients who received alternative donor transplants, only two remain in remission.

CONCLUSION

We conclude that well designed and controlled prospective studies are necessary to define the role of HSCTs in children with recurrent ALL. In order to be successful, such studies must have the full support of participating centers. Autologous HSC transplantation may have a role in the treatment of relapsed ALL, but further studies are needed.

Outcomes after HLA-matched sibling transplantation or chemotherapy in children with B-precursor acute lymphoblastic leukemia in a second remission: a collaborative study of the Children's Oncology Group and the Center for International Blood and Marrow Transplant Research

The best treatment approach for children with B-precursor acute lymphoblastic leukemia (ALL) in second clinical remission (CR) after a marrow relapse is controversial. To address this question, we compared outcomes in 188 patients enrolled in chemotherapy trials and 186 HLA-matched sibling transplants, treated between 1991 and 1997. Groups were similar except that chemotherapy recipients were younger (median age, 5 versus 8 years) and less likely to have combined marrow and extramedullary relapse (19% versus 30%). To adjust for time-to-transplant bias, treatment outcomes were compared using left-truncated Cox regression models. The relative efficacy of chemotherapy and transplantation depended on time from diagnosis to first relapse and the transplant conditioning regimen used. For children with early first relapse (< 36 months), risk of a second relapse was significantly lower after total body irradiation (TBI)-containing transplant regimens (relative risk [RR], 0.49; 95% confidence interval [CI] 0.33-0.71, P < .001) than chemotherapy regimens. In contrast, for children with a late first relapse (> or = 36 months), risks of second relapse were similar after TBI-containing regimens and chemotherapy (RR, 0.92; 95% CI, 0.49-1.70, P = .78). These data support HLA-matched sibling donor transplantation using a TBI-containing regimen in second CR for children with ALL and early relapse.

Recurrent Acute Lymphoblastic Leukemia Presenting in the Lacrimal Gland

A 14-year-old girl with a history of acute lymphoblastic leukemia presented with periorbital swelling of the right eyelid associated with enlargement of the lacrimal gland and cervical lymphadenopathy. Radiographic imaging showed diffuse enlargement and enhancement of the right lacrimal gland. The patient underwent an incisional biopsy of the lacrimal gland that showed atypical lymphocytes consistent with recurrent acute lymphoblastic leukemia. The lacrimal gland is a rare extramedullary site for recurrence of this disease.

Prognostic factors for relapsed childhood acute lymphoblastic leukemia: impact of allogeneic stem cell transplantation--a report from the Kyushu-Yamaguchi Children's Cancer Study Group

BACKGROUND

The treatment results of childhood acute lymphoblastic leukemia (ALL) with a first relapse were retrospectively analyzed to determine prognostic factors. In particular, an attempt was made to clarify whether stem cell transplantation (SCT) had any advantages over chemotherapy.

PROCEDURES

Of the 407 children with ALL diagnosed between 1984 and 1996, 117 suffered from a relapse before December 1999. The patients were treated differently according to the protocols of each institution. The potential prognostic factors examined were: the time of initial diagnosis, gender, immunophenotype of leukemic blasts and the NCI-risk classification at initial diagnosis, the site of relapse, the time of relapse (early: within 18 months after diagnosis, intermediate: other than either early or late relapse, late: later than 6 months after the discontinuation of front-line chemotherapy), and the treatment after relapse (chemotherapy alone and SCT).

RESULTS

A second complete remission (CR2) was achieved in 90 patients (77%) and thirty of them maintained CR2, thus resulting in an event-free survival rate (EFS) of 25.1% and an overall survival rate of 26.1%. The significant prognostic factors identified by a multivariate analysis included the time of relapse (EFS: early 16.2%, intermediate 23.9%, late 35.1%, P = 0.012) and the treatment after relapse (EFS: SCT 30.3%, chemotherapy 22.0%, P = 0.049). When patients with an isolated bone marrow relapse and continuous CR2 for more than 3 months were analyzed, the treatment in CR2 was the only independent prognostic factor (EFS: SCT 60.2%, chemotherapy 25.7%, P = 0.005).

CONCLUSIONS

In children with ALL and a first relapse, the time of relapse and the treatment after relapse were found to be independent prognostic factors. Allogeneic SCT in CR2 showed significantly better results than chemotherapy in patients with an isolated bone marrow relapse.

Children and adults with acute lymphoblastic leukaemia have similar gene expression profiles

OBJECTIVES

To compare the gene expression pattern in children and adults with acute lymphoblastic leukaemia (ALL) in order to improve our understanding of the difference in disease biology and prognosis.

METHODS

The gene expression profiles in diagnostic samples from 29 children and 15 adults with ALL were analysed using the oligonucleotide chip Hu95ver2a, produced by Affymetrix.

RESULTS

Unsupervised hierarchical cluster analysis revealed that, in spite of differences in outcome, patients clustered irrespective of age, first by T-cell or B-precursor immunophenotype, and second by cytogenetic changes within the B-precursor group. The expression pattern analysis allowed the reclassification of some samples into the proper cytogenetic group. We also showed that separate clustering of samples with the BCR/ABL translocation could be explained by different breakpoint regions in the BCR. No significant difference in gene expression was observed between samples with and without CDKN2A deletion within the B-precursor group. Analysis of different age groups revealed a similarity in expression profiles when infants with the MLL translocation and adults over 40 yr of age were compared irrespective of karyotype.

CONCLUSIONS

In spite of the difference in clinical outcome, the gene expression pattern in children and adults with ALL is very similar and is primarily dependent on immunophenotype and cytogenetic aberrations. However, when age groups are compared, the expression patterns of infants and adults over 40 show a remarkable similarity.

Second induction in pediatric patients with recurrent acute lymphoid leukemia using DFCI-ALL protocols

Between 15% and 30% of children with acute lymphoblastic leukemia (ALL) experience disease recurrence. With the possible exception of patients presenting with late isolated extramedullary relapse, induction of second complete remission (CR) is employed as a stepping stone to allogeneic hematopoietic stem cell transplantation (HSCT). The authors report their institutional experience in the management of children with recurrent ALL using the Dana Farber Cancer Institute (DFCI) ALL protocol in patients treated initially with that same protocol. Successful reinduction was followed by allogeneic HSCT when possible. Between April 1986 and May 2003, 34 patients with recurrent ALL, treated at initial diagnosis with DFCI-ALL protocol therapy, were given the same protocol as repeat induction chemotherapy. The median age was 4.6 years at diagnosis and 7.1 years at recurrence. Median duration of CR1 was 30.3 months. Second CR was obtained in 29 (85%) patients. Twenty went on to allogeneic HSCT; 10 of them currently remain in CR. Two additional patients treated with chemotherapy without HSCT are also in continuous CR2. Overall, 13 (38%) of the 34 patients are alive with a median follow-up of 105 months. There were no toxic deaths due to the reinduction therapy. One child died of cardiac failure after autologous HSCT. The treatment of children with recurrent ALL using the DFCI-ALL protocol induction regimen after initial use of the same protocol is associated with a high rate of second CR with no excess toxicity. However, the overall prognosis in these patients remains unsatisfactory and needs to be improved.

Inter-platform comparability of microarrays in acute lymphoblastic leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy and has been the poster-child for improved therapeutics in cancer, with life time disease-free survival (LTDFS) rates improving from <10% in 1970 to >80% today. There are numerous known genetic prognostic variables in ALL, which include T cell ALL, the hyperdiploid karyotype and the translocations: t(12;21)[TEL-AML1], t(4;11)[MLL-AF4], t(9;22)[BCR-ABL], and t(1;19)[E2A-PBX]. ALL has been studied at the molecular level through expression profiling resulting in un-validated expression correlates of these prognostic indices. To date, the great wealth of expression data, which has been generated in disparate institutions, representing an extremely large cohort of samples has not been combined to validate any of these analyses. The majority of this data has been generated on the Affymetrix platform, potentially making data integration and validation on independent sample sets a possibility. Unfortunately, because the array platform has been evolving over the past several years the arrays themselves have different probe sets, making direct comparisons difficult. To test the comparability between different array platforms, we have accumulated all Affymetrix ALL array data that is available in the public domain, as well as two sets of cDNA array data. In addition, we have supplemented this data pool by profiling additional diagnostic pediatric ALL samples in our lab. Lists of genes that are differentially expressed in the six major subclasses of ALL have previously been reported in the literature as possible predictors of the subclass.

RESULTS

We validated the predictability of these gene lists on all of the independent datasets accumulated from various labs and generated on various array platforms, by blindly distinguishing the prognostic genetic variables of ALL. Cross-generation array validation was used successfully with high sensitivity and high specificity of gene predictors for prognostic variables. We have also been able to validate the gene predictors with high accuracy using an independent dataset generated on cDNA arrays.

CONCLUSION

Interarray comparisons such as this one will further enhance the ability to integrate data from several generations of microarray experiments and will help to break down barriers to the assimilation of existing datasets into a comprehensive data pool.