Minimal residual disease and outcome characteristics in infant KMT2A-germline acute lymphoblastic leukaemia treated on the Interfant-06 protocol

BACKGROUND

The outcome of infants with KMT2A-germline acute lymphoblastic leukaemia (ALL) is superior to that of infants with KMT2A-rearranged ALL but has been inferior to non-infant ALL patients. Here, we describe the outcome and prognostic factors for 167 infants with KMT2A-germline ALL enrolled in the Interfant-06 study.

METHODS

Univariate analysis on prognostic factors (age, white blood cell count at diagnosis, prednisolone response and CD10 expression) was performed on KMT2A-germline infants in complete remission at the end of induction (EOI; n = 163). Bone marrow minimal residual disease (MRD) was measured in 73 patients by real-time quantitative polymerase chain reaction at various time points (EOI, n = 68; end of consolidation, n = 56; and before OCTADAD, n = 57). MRD results were classified as negative, intermediate (<5∗10^-4), and high (≥5∗10^-4).

RESULTS

The 6-year event-free and overall survival was 73.9% (standard error [SE] = 3.6) and 87.2% (SE = 2.7). Relapses occurred early, within 36 months from diagnosis in 28 of 31 (90%) infants. Treatment-related mortality was 3.6%. Age <6 months was a favourable prognostic factor with a 6-year disease-free survival (DFS) of 91% (SE = 9.0) compared with 71.7% (SE = 4.2) in infants >6 months of age (P = 0.04). Patients with high EOI MRD ≥5 × 10^-4 had a worse outcome (6-year DFS 61.4% [SE = 12.4], n = 16), compared with patients with undetectable EOI MRD (6-year DFS 87.9% [SE = 6.6], n = 28) or intermediate EOI MRD <5 × 10^-4 (6-year DFS 76.4% [SE = 11.3], n = 24; P = 0.02).

CONCLUSION

We conclude that young age at diagnosis and low EOI MRD seem favourable prognostic factors in infants with KMT2A-germline ALL and should be considered for risk stratification in future clinical trials.

A Semi-Mechanistic Population Pharmacokinetic/Pharmacodynamic Model of Bortezomib in Pediatric Patients with Relapsed/Refractory Acute Lymphoblastic Leukemia

INTRODUCTION

The pharmacokinetics (PK) of the 20S proteasome inhibitor bortezomib are characterized by a large volume of distribution and a rapid decline in plasma concentrations within the first hour after administration. An increase in exposure was observed in the second week of treatment, which has previously been explained by extensive binding of bortezomib to proteasome in erythrocytes and peripheral tissues. We characterized the nonlinear population PK and pharmacodynamics (PD) of bortezomib in children with acute lymphoblastic leukemia.

METHODS

Overall, 323 samples from 28 patients were available from a pediatric clinical study investigating bortezomib at an intravenous dose of 1.3 mg/m² twice weekly (Dutch Trial Registry number 1881/ITCC021). A semi-physiological PK model for bortezomib was first developed; the PK were linked to the decrease in 20S proteasome activity in the final PK/PD model.

RESULTS

The plasma PK data were adequately described using a two-compartment model with linear elimination. Increased concentrations were observed in week 2 compared with week 1, which was described using a Langmuir binding model. The decrease in 20S proteasome activity was best described by a direct effect model with a sigmoidal maximal inhibitory effect, representing the relationship between plasma concentrations and effect. The maximal inhibitory effect was 0.696 pmol AMC/s/mg protein (95% confidence interval 0.664-0.728) after administration.

CONCLUSION

The semi-physiological model adequately described the nonlinear PK and PD of bortezomib in plasma. This model can be used to further optimize dosing of bortezomib.

The MLL recombinome of acute leukemias in 2017

Chromosomal rearrangements of the human MLL/KMT2A gene are associated with infant, pediatric, adult and therapy-induced acute leukemias. Here we present the data obtained from 2345 acute leukemia patients. Genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) were determined and 11 novel TPGs were identified. Thus, a total of 135 different MLL rearrangements have been identified so far, of which 94 TPGs are now characterized at the molecular level. In all, 35 out of these 94 TPGs occur recurrently, but only 9 specific gene fusions account for more than 90% of all illegitimate recombinations of the MLL gene. We observed an age-dependent breakpoint shift with breakpoints localizing within MLL intron 11 associated with acute lymphoblastic leukemia and younger patients, while breakpoints in MLL intron 9 predominate in AML or older patients. The molecular characterization of MLL breakpoints suggests different etiologies in the different age groups and allows the correlation of functional domains of the MLL gene with clinical outcome. This study provides a comprehensive analysis of the MLL recombinome in acute leukemia and demonstrates that the establishment of patient-specific chromosomal fusion sites allows the design of specific PCR primers for minimal residual disease analyses for all patients.

Non-anaplastic peripheral T cell lymphoma in children and adolescents-an international review of 143 cases

Peripheral T cell lymphomas (PTCL) are rare in children and adolescents, and data about outcome and treatment results are scarce. The present study is a joint, international, retrospective analysis of 143 reported cases of non-anaplastic PTCL in patients <19 years of age, with a focus on treatment and outcome features. One hundred forty-three patients, between 0.3 and 18.7 years old, diagnosed between 2000 and 2015 were included in the study. PTCL not otherwise specified was the largest subgroup, followed by extranodal NK/T cell lymphoma, hepatosplenic T cell lymphoma (HS TCL), and subcutaneous panniculitis-like T cell lymphoma (SP TCL). Probability of overall survival (pOS) at 5 years for the whole group was 0.56 ± 0.05, and probability of event-free survival was (pEFS) 0.45 ± 0.05. Patients with SP TCL had a good outcome with 5-year pOS of 0.78 ± 0.1 while patients with HS TCL were reported with 5-year pOS of only 0.13 ± 0.12. Twenty-five percent of the patients were reported to have a pre-existing condition, and this group had a dismal outcome with 5-year pOS of 0.29 ± 0.09. The distribution of non-anaplastic PTCL subtypes in pediatric and adolescent patients differs from what is reported in adult patients. Overall outcome depends on the subtype with some doing better than others. Pre-existing conditions are frequent and associated with poor outcomes. There is a clear need for subtype-based treatment recommendations for children and adolescents with PTCL.

Preexisting conditions in pediatric ALL patients: Spectrum, frequency and clinical impact

INTRODUCTION

The etiology of acute lymphoblastic leukemia remains undisclosed in the majority of cases. A number of rare syndromic conditions are known to predispose to different forms of childhood cancer including ALL. The present study characterized the spectrum and clinical impact of preexisting diseases in a cohort of ALL patients from Germany, Austria and Switzerland with a focus on genetic diseases predisposing to cancer development.

METHODS

Retrospective database and study chart review included all patients from Germany, Austria and Switzerland (n = 4939) enrolled into multicenter clinical trial AIEOP-BFM ALL 2000 between July 1999 and June 2009. Patients enrolled into study AIEOP-BFM ALL 2009 - which was initiated subsequent to AIEP-BFM ALL 2000 - who were reported with a cancer prone syndrome or chromosomal abnormality were additionally included in this study to increase conclusiveness of observations.

RESULTS

A total of 233 patients with at least one reported condition could be identified. The following conditions were reported in more than one patient: Gilbert's disease (n = 13), neurofibromatosis type I (n = 8), ataxia telangiectasia (n = 8), thalassemia (n = 7), Nijmegen Breakage syndrome (n = 6), cystic fibrosis (n = 4), glucose-6-phosphate dehydrogenase deficiency (n = 4), Noonan syndrome (n = 2), Klinefelter syndrome (n = 2), alpha-1-antitrypsin deficiency (n = 2), primary ciliary dyskinesia (n = 2). Especially those syndromes with a known cancer predisposition (NF type I, Ataxia telangiectasia, Nijmegen Breakage syndrome etc.) were associated with certain general and ALL-related characteristics, high therapy-related toxicity and reduced survival.

CONCLUSION

The spectrum of underlying diseases within ALL patients is dispersed. A small number of ALL patients are reported with cancer predisposition syndromes at initial diagnosis which are associated with high rates of therapy-related toxicity and a markedly reduced chance of survival. The true prevalence of these conditions within the ALL population remains unknown due to inapparent clinical presentation. A targeted clinical and/or genetic examination for certain diagnoses like NF type I, Ataxia telangiectasia or Nijmegen Breakage syndrome could identify patients who benefit from adjustment of antileukemic therapy or intensification of supportive care.

Minimal residual disease-based treatment is adequate for relapse-prone childhood acute lymphoblastic leukemia with an intrachromosomal amplification of chromosome 21: the experience of the ALL-BFM 2000 trial

BACKGROUND

Recently, the UK CCLG and COG reported that an intrachromosomal amplification of chromosome 21 (iAMP21) in acute lymphoblastic leukemia (ALL) loses its adverse prognostic impact with intensified therapy.

PATIENT AND METHODS

We evaluated the prognosis of iAMP21 among patients from the ALL-BFM (Berlin-Frankfurt-Münster) 2000 trial with 46 of 2 637 (2%) patients iAMP21+.

RESULTS

8-year event-free-survival (EFS, 64 ± 8% vs. 81 ± 1%, p=0.0026) and cumulative incidence of relapse (CIR, 29 ± 8% vs. 14 ± 1%, p=0.008) of the iAMP21 cases were significantly worse compared with non-iAMP21 patients. Within the MRD low-risk group, iAMP21 cases (n=14) had an inferior 8-year EFS (76 ± 12% vs. 92 ± 1%, p=0.0081), but no increased CIR (10 ± 10% vs. 6 ± 1%, p=0.624). Within the MRD intermediate-risk group, iAMP21 cases (n=27) had a worse 8-year EFS (56 ± 11% vs. 78 ± 2%, p=0.0077) and CIR (44 ± 11% vs. 20 ± 2%, p=0.003) with 6/10 relapses occurring after 2 years.

CONCLUSIONS

Conclusively, we believe that there is no necessity for enrolling all iAMP21 patients into the high-risk arm of ongoing ALL-BFM trials because MRD low-risk patients have a moderate relapse risk under current therapy. Whether the increased relapse risk in MRD intermediate-risk patients can be avoided by late treatment intensification remains to be answered by the AIEOP-BFM ALL 2009 trial randomly using protracted pegylated L-asparaginase during delayed intensification and early maintenance.

Blocking ETV6/RUNX1-induced MDM2 overexpression by Nutlin-3 reactivates p53 signaling in childhood leukemia

ETV6/RUNX1 (E/R) is the most common fusion gene in childhood acute lymphoblastic leukemia. It is responsible for the initiation of leukemia but also indispensable for disease maintenance and propagation, although its function in these latter processes is less clear. We therefore investigated the effects of the perceived p53 pathway alterations in model cell lines and primary leukemias and, in particular, how E/R upregulates MDM2, the predominant negative regulator of p53. We found that E/R transactivates MDM2 in both p53(+/+) and p53(-/-) HCT116 cells by binding to promoter-inherent RUNX1 motifs, which indicates that this activation occurs in a direct and p53-independent manner. Treatment of E/R-positive leukemic cell lines with Nutlin-3, a small molecule that inhibits the MDM2/p53 interaction, arrests their cell cycle and induces apoptosis. These phenomena concur with a p53-induced expression of p21, pro-apoptotic BAX and PUMA, as well as caspase 3 activation and poly ADP-ribose polymerase cleavage. The addition of DNA-damaging and p53-activating chemotherapeutic drugs intensifies apoptosis. Moreover, Nutlin-3 exposure leads to an analogous p53 accumulation and apoptotic surge in E/R-positive primary leukemic cells. Our findings clarify the role of p53 signaling in E/R-positive leukemias and outline the potential basis for its therapeutic exploitation in this setting.

Prediction of outcome by early response in childhood acute lymphoblastic leukemia

BACKGROUND

In the ALL-BFM studies for treatment of acute lymphoblastic leukemia, reduction of leukemic blasts in peripheral blood after a one-week prednisone pre-phase - the so-called prednisone response - has been used for risk stratification since the 1980s and has been one of the most relevant factors for identification of high-risk patients. In the trial ALL-BFM 95, early cytomorphological marrow response on day 15 of induction therapy was prospectively evaluated and its prognostic value was analyzed in comparison to the prednisone response and other established prognostic factors.

RESULTS

Compared to prednisone response, day 15 marrow response was superior in outcome prediction - yet with differential effect depending on blast lineage. Outcome was poor in T cell leukemia patients with prednisone poor-response independent of day 15 marrow response, whereas among patients with prednisone good-response different risk groups could be identified by day 15 marrow response. In contrast, prednisone response lost prognostic significance in precursor B cell leukemia when stratified by day 15 marrow response.

CONCLUSIONS

Selective addition of day 15 marrow response to conventional stratification criteria applied on ALL-BFM 95 may significantly improve risk-adapted treatment delivery. Even though cutting-edge trial risk stratification is meanwhile dominated by minimal residual disease evaluation, an improved conventional risk assessment, as presented here, could be of great importance to countries lacking the technical and/or financial resources associated with the application of minimal residual disease analysis.

Non-Hodgkin's lymphoma in adolescents: experiences in 378 adolescent NHL patients treated according to pediatric NHL-BFM protocols

Age-related differences in the distribution, biology and treatment response of non-Hodgkin's lymphoma (NHL) in adolescents remain to be elucidated. The current analyses present clinical parameters and outcomes of adolescents treated in pediatric NHL-BFM trials. Patients were stratified by histological subtype: lymphoblastic lymphoma (LBL); mature B-NHL, including Burkitt's lymphoma/leukemia (BL/B-AL), diffuse B-cell lymphoma (DLBCL-CB) and mediastinal B-cell lymphoma (PMLBL); and anaplastic large cell lymphoma (ALCL). Between October 1986 and December 2007, 2915 patients were registered, including 378 (13%) adolescents (15-18 years) with BL/B-AL (n=101), ALCL (n=74), DLBCL-CB (n=55), T-LBL (n=45), PMLBL (n=24), pB-LBL (n=13) and rare or not-specified NHL subtypes (n=66). The 5-year event-free survival (EFS) was 79±2% for adolescents compared with 85±1% for patients aged <15 years (P=0.014). EFS was 83±7% for adolescents with T-LBL, 82±4% with BL/B-AL, 85±5% with DLBCL-CB, 57±10% with PMLBL and 70±6% with ALCL. According to sex, the 5-year EFS in females versus males, respectively, was 70±5 versus 83±2% overall (P=0.004), 57±17 versus 92±6% (P=0.0036) for T-LBL patients and 71±9 versus 97±3% (P=0.0067) for DLBCL-CB patients. Adolescents with NHL treated according to pediatric NHL-BFM protocols had an EFS of 79±2%, which is marginally inferior to that of children. In adolescents with T-LBL and DLBCL-CB, female sex was associated with a worse prognosis.

Distinct fluctuations of ammonia levels during asparaginase therapy for childhood acute leukemia

BACKGROUND

The enzyme asparaginase (L-Asp) catalyses the hydrolysis of the non-essential amino acids asparagine and glutamine to aspartic and glutamic acid and ammonia. Ammonia therefore represents a direct metabolite of the biochemical reaction induced by this enzyme. However, data regarding the dynamics and clinical relevance of ammonia levels during L-Asp therapy are lacking.

PROCEDURE

We prospectively followed the dynamics of ammonia levels during L-Asp containing induction therapy according to the ALL-BFM 2000 protocol in 10 pediatric patients with acute lymphoblastic leukemia (ALL), in order to assess the possible relevance of ammonia levels for clinical practice and its use as a possible surrogate parameter of L-Asp enzyme activity.

RESULTS

We observed a significant elevation of ammonia levels 1 day after intravenous L-Asp administration with ammonia levels reaching up to the seventh fold of normal values, followed by a steep decline to basal values within another 2 days, resulting in an undulating course of ammonia concentrations during L-Asp containing induction treatment.

CONCLUSIONS

Although there are potential neurotoxic properties of ammonia, central nervous system (CNS) toxicity has not been observed in our study and is generally not seen as a common side effect of L-Asp therapy. Furthermore, due to the characteristic fluctuation profile, ammonia levels may represent a suitable surrogate parameter of L-Asp enzyme activity and may enable the monitoring of silent inactivation of L-Asp.

Importance of allogeneic T-cells for disease control after stem cell transplantation for high-risk Langerhans cell histiocytosis

Reduced intensity conditioning followed by allogeneic SCT (RIC-SCT) has recently emerged as promising new salvage option for children suffering from Langerhans cell histiocytosis (LCH) with risk organ involvement and failure to conventional therapy. We report on the posttransplant course of female toddler with high-risk LCH, who achieved complete remission after RIC-SCT, despite a posttransplant chimerism constellation, in which only the T-cell subset proved to be of donor origin in the long-term. We therefore suggest that allogeneic T-cells have played a crucial role in controlling disease activity in this patient and may exert the major curative effect after RIC-SCT for LCH.

The MLL recombinome of acute leukemias

Chromosomal rearrangements of the human MLL gene are a hallmark for aggressive (high-risk) pediatric, adult and therapy-associated acute leukemias. These patients need to be identified in order to subject these patients to appropriate therapy regimen. A recently developed long-distance inverse PCR method was applied to genomic DNA isolated from individual acute leukemia patients in order to identify chromosomal rearrangements of the human MLL gene. We present data of the molecular characterization of 414 samples obtained from 272 pediatric and 142 adult leukemia patients. The precise localization of genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) was determined and several new TPGs were identified. The combined data of our study and published data revealed a total of 87 different MLL rearrangements of which 51 TPGs are now characterized at the molecular level. Interestingly, the four most frequently found TPGs (AF4, AF9, ENL and AF10) encode nuclear proteins that are part of a protein network involved in histone H3K79 methylation. Thus, translocations of the MLL gene, by itself coding for a histone H3K4 methyltransferase, are presumably not randomly chosen, rather functionally selected.

Improved outcome of treatment-resistant high-risk Langerhans cell histiocytosis after allogeneic stem cell transplantation with reduced-intensity conditioning

Children with multisystem Langerhans cell histiocytosis (LCH) and risk organ involvement who fail to respond to conventional chemotherapy have an extremely poor prognosis. Myeloablative stem cell transplantation (SCT) as a possible salvage approach for these patients has been associated with a high risk of transplant-related mortality. Therefore, allogeneic stem cell transplantation following a reduced-intensity conditioning regimen (RIC-SCT) has recently been performed as an alternative salvage approach. We report on the experience with allogeneic RIC-SCT in nine pediatric high-risk LCH patients. Conditioning regimen included fludarabine in all patients, melphalan in eight patients, total lymphoid irradiation in six patients, total body irradiation in two, antithymocyte globulin in five, and Campath in four patients. RIC-SCT was well tolerated with regard to common procedure-related complications. Two patients died 50 and 69 days after RIC-SCT, respectively. Seven out of the nine patients survived and showed no signs of disease activity (including one with nonengraftment and full autologous hematopoietic recovery) after median follow-up of 390 days post-SCT. Based on this observation, we conclude that RIC-SCT is a feasible procedure with low transplant-related morbidity and mortality and a promising new salvage approach for high-risk LCH patients with resistant risk organ involvement.

Incidence and relevance of secondary chromosome abnormalities in childhood TEL/AML1+ acute lymphoblastic leukemia: an interphase FISH analysis

The aim of the present study was to determine the frequency and clinical relevance of the most common secondary karyotype abnormalities in TEL/AML1+ B-cell precursor acute lymphoblastic leukemia (ALL) as assessed with fluorescence in situ hybridization (FISH) analyses. Screening of 372 patients who were enrolled in two consecutive Austrian childhood ALL multicenter trials identified 94 (25%) TEL/AML1+ cases. TEL deletions, trisomy 21 and an additional der(21)t(12;21) were detected in 52 (55%), 13 (14%) and 14 (15%) TEL/AML1+ patients, respectively. The 12p aberrations (P=0.001) and near tetraploidy (P=0.045) were more common in TEL/AML1+ patients, whereas the incidence of diploidy, pseudodiploidy, hypodiploidy, low hyperdiploidy, near triploidy, del(6q), chromosome 9 and 11q23 abnormalities was similar among TEL/AML1+ and TEL/AML1- patients. None of the TEL/AML1+ patients had a high hyperdiploid karyotype. Univariate analysis indicated that among TEL/AML1+ patients those with a deletion of the nontranslocated TEL allele had a worse prognosis than those without this abnormality (P=0.034). We concluded that the type and incidence of the most common secondary aberrations in TEL/AML1+ ALL can be conveniently identified with little additional effort during interphase screening with appropriate TEL and AML1 FISH probes. We also provided preliminary evidence that the deletion of the nontranslocated TEL allele may adversely influence the clinical course of TEL/AML1+ ALL.

Effects of Dose-Reduced Medac® L-Asparaginase on Coagulation in Trial ALL-BFM 2000

BACKGROUND

Glucocorticoids and L-asparaginase (L-ASP) are essential elements of contemporary chemotherapy of childhood acute lymphoblastic leukemia (ALL). Both cytotoxic drugs are well-known to induce significant alterations in hemostasis, especially affecting the inhibitors of coagulation including antithrombin III (AT III), protein C and protein S.

PATIENTS AND METHODS

The objectives of the present prospective study were to analyze the course and degree of the changes of several coagulation proteins during induction therapy of 16 patients treated according to the Berlin-Frankfurt-Münster (BFM) ALL protocol 2000. The induction protocol included a 7-day mono-therapy with glucocorticoids followed by 4 weeks with additional vincristine, daunorubicin and E. coli L-ASP (Medac) which was administered at a dosage of 5000 IU/m (2) 8-times at 3-day intervals.

RESULTS AND CONCLUSIONS

This analysis is the first to show that 5000 IU/m (2) of the Medac L-ASP leads to a less pronounced decrease of the plasma AT III and fibrinogen concentrations during induction therapy (after the 5 (th) L-ASP dose), as compared to previous BFM protocols which used the Medac L-ASP in a dosage of 10 000 IU/m (2). Our results confirmed that following a mono-therapy with glucocorticoids the AT III, protein C and protein S levels increased while the fibrinogen level decreased. As the D-Dimers remained within the normal range during the 3 weeks of L-ASP combination chemotherapy and none of the patients suffered a thromboembolic event, we also concluded that despite of the significant decrease of anticoagulant proteins, there might be a balance between coagulation and fibrinolysis; thus the D-Dimers may eventually serve as a helpful indicator for therapeutic interventions.

Neuroblastoma cells provoke Schwann cell proliferation in vitro

BACKGROUND

A subset of human neuroblastomas (NBs) has the capacity to mature completely, imitating sympathetic ganglia. Previously, we showed that the neuronal population in spontaneously maturing NBs usually has a near-triploid DNA content without 1p deletions, and we concluded that the constantly diploid Schwann cells (SCs) do not belong to the neoplastic component of these tumours. We therefore hypothesised that NB cells are able to stimulate SC proliferation, and that SCs trigger NB differentiation.

PROCEDURE

We performed in vitro experiments to test this model and to test whether SCs can also influence the growth of aggressive NBs. Human SCs were co-cultivated with NB tumours and cell lines, and were harvested after defined time intervals. Proliferative activity of the SCs and the NB cells was determined by visualisation of 5-bromo-2'-deoxyuridine (BrdU) incorporation or Ki-67 staining. Neurite outgrowth and neurofilament (NF) expression were analysed immunocytochemically and apoptotic rate was determined by a terminal deoxynucleotidyl transferase-mediated dUTP-X fluorescein nick end labelling (TUNEL) assay.

RESULTS

Human NB tumours or cell lines unequivocally increased the proliferation of SCs in vitro. In cocultivated NB cells, the proliferative activity was not altered in the first days of cocultivation, although neurite outgrowth and NF expression were enhanced. However, after 10 days, the mitotic rate of neuroblastic cells decreased and the apoptotic rate showed a marked increase.

CONCLUSIONS

The results of the cocultivation experiments provide an experimental hint that the in vivo growth of SCs in NBs is caused by the neoplastic neuroblasts, and they also indicate that cells from peripheral nerves can influence the growth of aggressive NB cells if cocultivated.