Bone mineral density in children with acute lymphoblastic leukemia

BACKGROUND

Children with acute lymphoblastic leukemia (ALL) can develop reduced bone mineral density (BMD). However, data from patients who received treatment on a frontline regimen without cranial irradiation are limited, and no genome-wide analysis has been reported.

METHODS

Lumbar BMD was evaluated by quantitative computed tomography at diagnosis, after 120 weeks of continuation therapy, and after 2 years off therapy in pediatric patients with ALL (ages 2-18 years at diagnosis) who were treated on the St. Jude Total XV Protocol. Clinical, pharmacokinetic, and genetic risk factors associated with decreased BMD Z-scores were evaluated.

RESULTS

The median BMD Z-score in 363 patients was 0.06 at diagnosis, declined to -1.08 at week 120, but partly recovered to -0.72 after 2 years off therapy; BMD in patients with low BMD Z-scores at diagnosis remained low after therapy. Older age (≥10 years vs 2-9.9 years at diagnosis; P < .001), a higher BMD Z-score at diagnosis (P = .001), and a greater area under the plasma drug concentration-time curve for dexamethasone in weeks 7 and 8 of continuation therapy (P = .001) were associated with a greater decrease in BMD Z-score from diagnosis to week 120. Single-nucleotide polymorphisms in 2 genes important in osteogenesis and bone mineralization (COL11A1 [reference single-nucleotide polymorphism rs2622849]; P = 2.39 × 10^-7 ] and NELL1 [rs11025915]; P = 4.07 × 10^-6 ]) were associated with a decreased BMD Z-score. NELL1 (P = .003) also was associated with a greater dexamethasone area under the plasma drug concentration-time curve.

CONCLUSIONS

BMD Z-scores decreased during therapy, especially in patients who had clinical, pharmacokinetic, and genetic risk factors. Early recognition of BMD changes and strategies to optimize bone health are essential. Cancer 2018;124:1025-35. © 2017 American Cancer Society.

Hypoxia-induced upregulation of BMX kinase mediates therapeutic resistance in acute myeloid leukemia

Oncogenic addiction to the Fms-like tyrosine kinase 3 (FLT3) is a hallmark of acute myeloid leukemia (AML) that harbors the FLT3-internal tandem duplication (FLT3-ITD) mutation. While FLT3 inhibitors like sorafenib show initial therapeutic efficacy, resistance rapidly develops through mechanisms that are incompletely understood. Here, we used RNA-Seq-based analysis of patient leukemic cells and found that upregulation of the Tec family kinase BMX occurs during sorafenib resistance. This upregulation was recapitulated in an in vivo murine FLT3-ITD-positive (FLT3-ITD+) model of sorafenib resistance. Mechanistically, the antiangiogenic effects of sorafenib led to increased bone marrow hypoxia, which contributed to HIF-dependent BMX upregulation. In in vitro experiments, hypoxia-dependent BMX upregulation was observed in both AML and non-AML cell lines. Functional studies in human FLT3-ITD+ cell lines showed that BMX is part of a compensatory signaling mechanism that promotes AML cell survival during FLT3 inhibition. Taken together, our results demonstrate that hypoxia-dependent upregulation of BMX contributes to therapeutic resistance through a compensatory prosurvival signaling mechanism. These results also reveal the role of off-target drug effects on tumor microenvironment and development of acquired drug resistance. We propose that the bone marrow niche can be altered by anticancer therapeutics, resulting in drug resistance through cell-nonautonomous microenvironment-dependent effects.

Levofloxacin Prophylaxis During Induction Therapy for Pediatric Acute Lymphoblastic Leukemia

BACKGROUND

Infection is the most important cause of treatment-related morbidity and mortality in pediatric patients treated for acute lymphoblastic leukemia (ALL). Although routine in adults with leukemia, antibacterial prophylaxis is controversial in pediatrics because of insufficient evidence for its efficacy or antibiotic choice and concerns about promoting antibiotic resistance and Clostridium difficile infection.

METHODS

This was a single-center, observational cohort study of patients with newly diagnosed ALL, comparing prospectively collected infection-related outcomes in patients who received no prophylaxis, levofloxacin prophylaxis, or other prophylaxis during induction therapy on the total XVI study. A propensity score-weighted logistic regression model was used to adjust for confounders.

RESULTS

Of 344 included patients, 173 received no prophylaxis, 69 received levofloxacin prophylaxis, and 102 received other prophylaxis regimens. Patients receiving prophylaxis had longer duration of neutropenia. Prophylaxis reduced the odds of febrile neutropenia, likely bacterial infection, and bloodstream infection by ≥70%. Levofloxacin prophylaxis alone reduced these infections, but it also reduced cephalosporin, aminoglycoside, and vancomycin exposure and reduced the odds of C. difficile infection by >95%. No increase in breakthrough infections with antibiotic-resistant organisms was seen, but this cannot be excluded.

CONCLUSIONS

This is the largest study to date of antibacterial prophylaxis during induction therapy for pediatric ALL and the first to include a broad-spectrum fluoroquinolone. Prophylaxis prevented febrile neutropenia and systemic infection. Levofloxacin prophylaxis also minimized the use of treatment antibiotics and drastically reduced C. difficile infection. Although long-term antibiotic-resistance monitoring is needed, these data support using targeted prophylaxis with levofloxacin in children undergoing induction chemotherapy for ALL.

CLINICAL TRIALS REGISTRATION

NCT00549848.

Asparaginase-associated pancreatitis in childhood acute lymphoblastic leukaemia: an observational Ponte di Legno Toxicity Working Group study

BACKGROUND

Survival for childhood acute lymphoblastic leukaemia surpasses 90% with contemporary therapy; however, patients remain burdened by the severe toxic effects of treatment, including asparaginase-associated pancreatitis. To investigate the risk of complications and risk of re-exposing patients with asparaginase-associated pancreatitis to asparaginase, 18 acute lymphoblastic leukaemia trial groups merged data for this observational study.

METHODS

Patient files from 26 trials run by 18 trial groups were reviewed on children (aged 1·0-17·9 years) diagnosed with t(9;22)-negative acute lymphoblastic leukaemia between June 1, 1996, and Jan 1, 2016, who within 50 days of asparaginase exposure developed asparaginase-associated pancreatitis. Asparaginase-associated pancreatitis was defined by at least two criteria: abdominal pain, pancreatic enzymes at least three times the upper limit of normal (ULN), and imaging compatible with pancreatitis. Patients without sufficient data for diagnostic criteria were excluded. Primary outcomes were defined as acute and persisting complications of asparaginase-associated pancreatitis and risk of re-exposing patients who suffered an episode of asparaginase-associated pancreatitis to asparaginase. Data were collected from Feb 2, 2015, to June 30, 2016, and analysed and stored in a common database at Rigshospitalet, Copenhagen, Denmark.

FINDINGS

Of 465 patients with asparaginase-associated pancreatitis, 33 (8%) of 424 with available data needed mechanical ventilation, 109 (26%) of 422 developed pseudocysts, acute insulin therapy was needed in 81 (21%) of 393, and seven (2%) of 458 patients died. Risk of assisted mechanical ventilation, need for insulin, pseudocysts, or death was associated with older age (median age for patients with complications 10·5 years [IQR 6·4-13·8] vs without complications 6·1 years [IQR 3·6-12·2], p<0·0001), and having one or more affected vital signs (fever, hypotension, tachycardia, or tachypnoea; 96 [44%] of 217 patients with affected vital signs vs 11 [24%] of 46 patients without affected vital signs, p=0·02). 1 year after diagnosis of asparaginase-associated pancreatitis, 31 (11%) of 275 patients still needed insulin or had recurrent abdominal pain or both. Both the risk of persisting need for insulin therapy and recurrent abdominal pain were associated with having had pseudocysts (odds ratio [OR] 9·48 [95% CI 3·01-35·49], p=0·0002 for insulin therapy; OR 11·79 [4·30-37·98], p<0·0001 for recurrent abdominal pain). Within 8 years of asparaginase-associated pancreatitis, risk of abdominal symptoms dropped from 8% (26 of 312) to 0% (0 of 35) but the need for insulin therapy remained constant (9%, three of 35). 96 patients were re-exposed to asparaginase, including 59 after a severe asparaginase-associated pancreatitis (abdominal pain or pancreatic enzymes at least three times the ULN or both lasting longer than 72 h). 44 (46%) patients developed a second asparaginase-associated pancreatitis, 22 (52%) of 43 being severe. Risk of persisting need for insulin or abdominal pain after having had two versus one asparaginase-associated pancreatitis did not differ (three [7%] of 42 vs 28 [12%] of 233, p=0·51). Risk of a second asparaginase-associated pancreatitis was not associated with any baseline patient characteristics.

INTERPRETATION

Since the risk of a second asparaginase-associated pancreatitis was not associated with severity of the first asparaginase-associated pancreatitis and a second asparaginase-associated pancreatitis did not involve an increased risk of complications, asparaginase re-exposure should be determined mainly by the anticipated need for asparaginase for antileukaemic efficacy. A study of the genetic risk factors identifying patients in whom asparaginase exposure should be restricted is needed.

FUNDING

The Danish Childhood Cancer Foundation and The Danish Cancer Society (R150-A10181).

Decreased relapsed rate and treatment-related mortality contribute to improved outcomes for pediatric acute myeloid leukemia in successive clinical trials

BACKGROUND

Outcomes for children with acute myeloid leukemia (AML) have improved over the past 20 years even though the medications used for induction therapy have not changed.

METHODS

This study analyzed data from patients with AML who were enrolled in successive protocols (AML97 and AML02) to determine the contributors to the improved outcomes of the latter clinical trial.

RESULTS

There were significant improvements in 5-year overall survival (48.9% vs 71.2%; P < .0001) and event-free survival (43.5% vs 61.8%; P = .002) from AML97 to AML02. The 5-year cumulative incidence of early death (ED)/treatment-related mortality (TRM) was reduced for patients treated in AML02 (18.5% vs 7.9%; P = .007). Although the overall incidence of refractory disease (6.5% vs 5.6%; P = .736) and relapse (29.3% vs 21.0%; P = .12) did not differ between the 2 studies, patients with low-risk AML who were treated in AML02 had a reduced incidence of relapse (27.3% vs 8.8%; P = .036).

CONCLUSIONS

The improved outcomes of the AML02 trial resulted from improved disease control for low-risk patients and overall decreased ED/TRM. These results emphasize the importance of supportive-care measures throughout chemotherapy courses and hematopoietic cell transplantation and the value of treatment intensity for patients with low-risk AML while underscoring the need for novel therapy, rather than increased therapy intensity, for children with high-risk AML. Cancer 2017;123:3791-3798. © 2017 American Cancer Society.

Integration of Next-Generation Sequencing to Treat Acute Lymphoblastic Leukemia with Targetable Lesions: The St. Jude Children's Research Hospital Approach

Acute lymphoblastic leukemia (ALL) is the most common type of cancer in children. In recent Total Therapy studies conducted at St. Jude Children's Research Hospital, children with ALL had a 5-year overall survival of around 94%. This is the result of a combination of risk stratification based on the biological features of the leukemic cells and the response to treatment (as assessed by the detection of minimal residual disease), treatment modification based on pharmacodynamic and pharmacogenomic data, and improved supportive care. However, innovative approaches are required to further improve survival to as close to 100% as possible and to reduce the adverse effects of treatment. Next-generation sequencing of leukemic cell DNA and RNA, as well as of germline DNA, can identify submicroscopic genetic structural changes and sequence alterations that contribute to leukemogenesis. Next-generation sequencing data can be used to define new ALL subtypes, to help improve treatment response and reduce adverse effects, and to identify novel prognostic markers and therapeutic targets to facilitate personalized precision medicine. In this article, we describe our approach to detecting targetable lesions in patients with ALL by next-generation sequencing and explain how we integrate the sequencing data into the treatment of these patients.

The Role of Leukapheresis in the Current Management of Hyperleukocytosis in Newly Diagnosed Childhood Acute Lymphoblastic Leukemia

BACKGROUND

Hyperleukocytosis in children with acute lymphoblastic leukemia (ALL) has been associated with early morbidity and mortality. The use of leukapheresis in these children treated with contemporary therapy remains controversial.

PROCEDURE

We analyzed clinical data from patients enrolled onto frontline protocols for ALL (Total Therapy XV and XVI) between 2003 and 2014. We documented adverse events within the first 14 days in patients with a white blood cell (WBC) count ≥200 × 10(9) /l and reviewed their management.

RESULTS

Fifty-three (7.8%) of 678 consecutive pediatric patients with newly diagnosed ALL presented with hyperleukocytosis (median WBC count 393 × 10(9) /l; range 200-1,014). Two deaths in patients without initial hyperleukocytosis occurred within the first 2 weeks from diagnosis secondary to bacterial sepsis. A total of 21 (40%) patients with ALL and hyperleukocytosis developed grade 3 or 4 adverse events regardless of the use of leukapheresis (P > 0.99 and P = 0.19). Sixteen of 53 (30%) patients with ALL received low-dose chemotherapy for leukocytoreduction initially. One-third of patients received urate oxidase, and none of the patients with hyperleukocytosis required hemodialysis.

CONCLUSIONS

The early morbidity and mortality commonly associated with hyperleukocytosis in children with newly diagnosed ALL can be avoided with contemporary supportive care and conservative management possibly obviating the need for costly and potentially dangerous leukapheresis.

Abstract 4786: Integrated high-throughput screen to identify treatment leads for pediatric AML

While dramatic improvements in survival have been achieved for children and adolescents with acute myeloid leukemia (AML), some subtypes are associated with event free survival of &lt;40%. Given that significant improvements in long-term outcome are not expected with conventional therapy alone, new therapeutic strategies are urgently needed. Therefore, we conducted a high-throughput screen (HTS) to identify novel therapeutics for the treatment of pediatric AML. We selected a panel of 8 AML cell lines representing subtypes with the poorest prognosis. An initial primary screen was performed at a single concentration (10μM) with &gt;8000 compounds. Compounds with &gt;50% activity (N = 285) in the primary screen and known clinical candidates were prioritized for a secondary HTS performed in a dose-response manner (10 point curve, 0-10μM). Screening was performed using a 348-well plate format and a Biomek automation workstation for drug delivery. At 72 h cell viability was determined using Cell Titer Glo and automated Envision plate reader. Multiple drug classes had broad activity including: anti-malarials, cytotoxics (antimicrotubules, purine/pyrimidine antimetabolites, floxuridine, trimetrexate, topoI/II inhibitors), epigenetic modifiers (BET, DNMT and HDAC inhibitors), and agents targeting Bcl-2, Chk1, Parp, Hsp90, NF-êB, NAMPT, p53, proteasome, and Wee1. We validated 13 compounds from select drug classes (artesunate, cytarabine, gemcitabine, cabazitaxel, depsipeptide, panobinostat, vorinostat, ABT-199, RG117, bortezomib, carfilizomab, BMN673, MK-1775) using primary blast samples representing 3 high-risk groups (FLT3-ITD-positive, MLL-rearranged, FAB M7). Given the broad activity of gemcitabine and cabazitaxel across AML subtypes and the ability for repurposing in childhood AML, we further evaluated these agents alone and in combination in vitro. After 72h exposure, cabazitaxel was a potent inhibitor of viability in AML cell lines (IC50, 3-11nM) and primary blast samples (IC50, 3.4nM to &gt;10μM); gemcitabine had similar activity (IC50, 3-62nM and 102nM to &gt;10μM, respectively). The combination was evaluated using continuous and sequential administration schedules for up to 72h of treatment in several cell lines; simultaneous treatments were synergistic (CI, 0.2-0.45) and sequential treatments were additive to synergistic (CI, 0.82-0.95). Tolerable combination regimens were identified in NSG mice (5mg/kg cabazitaxel + 50mg/kg gemcitabine q3d x 4 weeks or q4d x 3 weeks) and efficacy studies in AML xenografts and primagrafts are ongoing. Further studies will aim to determine the underlying mechanisms of AML sensitivity to gemcitabine, cabazitaxel, and the combination. Our comprehensive approach to identify treatment leads provide advances in understanding the biology of a heterogeneous disease and development of novel treatment strategies with potential clinical benefit for pediatric AML.

Citation Format: Christina D. Drenberg, Anang Shelat, Shelley J. Orwick, Hiroto Inaba, Raul C. Ribeiro, Jeffrey E. Rubnitz, Tanja A. Gruber, R K. Guy, Sharyn D. Baker. Integrated high-throughput screen to identify treatment leads for pediatric AML. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4786.

NUDT15 polymorphisms alter thiopurine metabolism and hematopoietic toxicity

Widely used as anticancer and immunosuppressive agents, thiopurines have narrow therapeutic indices owing to frequent toxicities, partly explained by TPMT genetic polymorphisms. Recent studies identified germline NUDT15 variation as another critical determinant of thiopurine intolerance, but the underlying molecular mechanisms and the clinical implications of this pharmacogenetic association remain unknown. In 270 children enrolled in clinical trials for acute lymphoblastic leukemia in Guatemala, Singapore and Japan, we identified four NUDT15 coding variants (p.Arg139Cys, p.Arg139His, p.Val18Ile and p.Val18_Val19insGlyVal) that resulted in 74.4-100% loss of nucleotide diphosphatase activity. Loss-of-function NUDT15 diplotypes were consistently associated with thiopurine intolerance across the three cohorts (P = 0.021, 2.1 × 10(-5) and 0.0054, respectively; meta-analysis P = 4.45 × 10(-8), allelic effect size = -11.5). Mechanistically, NUDT15 inactivated thiopurine metabolites and decreased thiopurine cytotoxicity in vitro, and patients with defective NUDT15 alleles showed excessive levels of thiopurine active metabolites and toxicity. Taken together, these results indicate that a comprehensive pharmacogenetic model integrating NUDT15 variants may inform personalized thiopurine therapy.

Multikinase Inhibitors Induce Cutaneous Toxicity through OAT6-Mediated Uptake and MAP3K7-Driven Cell Death

The use of multikinase inhibitors (MKI) in oncology, such as sorafenib, is associated with a cutaneous adverse event called hand-foot skin reaction (HFSR), in which sites of pressure or friction become inflamed and painful, thus significantly impacting quality of life. The pathogenesis of MKI-induced HFSR is unknown, and the only available treatment options involve dose reduction or discontinuation of therapy, which have negative effects on primary disease management. To investigate the underlying mechanisms by which sorafenib promotes keratinocyte cytotoxicity and subsequent HFSR induction, we performed a transporter-directed RNAi screen in human epidermal keratinocytes and identified SLC22A20 (OAT6) as an uptake carrier of sorafenib. Further investigations into the intracellular mechanism of sorafenib activity through in situ kinome profiling identified the mitogen-activated protein kinase MAP3K7 (TAK1) as a target of sorafenib that induces cell death. Finally, we demonstrate that sorafenib induced keratinocyte injury in vivo and that this effect could be reversed by cotreatment with the OAT6 inhibitor probenecid. Collectively, our findings reveal a novel pathway that regulates the entry of some MKIs into keratinocytes and explains the basis underlying sorafenib-induced skin toxicity, with important implications for the therapeutic management of HFSR.

Abstract 2033: Germline mutations in ETV6 confer risk of thrombocytopenia and acute lymphocytic leukemia

Germline mutations of transcription factors (e.g. PAX5, CEBPA, GATA2, RUNX1) have been associated with an inherited susceptibility to acute leukemia. Here we report 2 unrelated kindreds harboring germline mutations in ETV6, the gene encoding the transcription factor ETS variants 6. These kindreds were primarily characterized by thrombocytopenia and acute lymphoblastic leukemia (ALL). The first kindred, identified at MSKCC and HMC, includes 9 individuals with thrombocytopenia, and 3 individuals with pre-B ALL. Sequencing a subset of common and somatically altered leukemia genes in this family identified a rare heterozygous non-synonymous missense variation (T&gt;C) in 6 family members with thrombocytopenia and 2 with ALL. Notably, this variant did not segregate in 9 individuals in the kindred without these phenotypes. The amino acid alteration is predicted to lead to an L349P substitution within the DNA binding domain of ETV6 (L349P, NPP_001978). In silico analyses using SIFT and Polyphen assigned pathogenic variant classifications to the L349P variant. The proband of the second family presented to SJCRH with pre-B ALL, a history of thrombocytopenia, and demonstrated hypersensitivity to methotrexate (grade 3 bone marrow suppression). His leukemia transformated to myelodsyplastic syndrome and acute myeloid leukemia, which was treated by unrelated donor transplantation. The proband's mother, maternal aunt and maternal grandfather had thrombocytopenia, and the maternal great grandfather was diagnosed with chronic myeloid leukemia. The proband and his mother were found to carry a heterozygous 5 bp deletion in ETV6, N385fs (c.1153-5_1153_1delAACAG), which is predicted to produce a truncated protein of 389 amino acids with the last 4 residues different from the canonical ETV6 sequence. This variant has not been described in public sequencing data repositories. Finally, a review of 1,120 cases from the SJCRH/Washington University Pediatric Cancer Genome Project, including 588 cases of leukemia (among which 472 were ALL), revealed 3 rare germline ETV6 variants: L442P (n = 1), R181H (n = 1), and V37M (n = 1), with 2 of these variants L442P and R181H predicted to be pathogenic based on prediction and/or genomic location. Notably, these 2 variants each occurred in patients with ALL.

Collectively, these findings suggest that germline ETV6 mutations are associated with a novel syndrome of thrombocytopenia with susceptibility to leukemia. Furthermore, these mutations may account for approximately 0.4% (2/472) of pediatric ALL cases. Further phenotypic characterization of affected patients and functional assessment of ETV6 germline variants, in progress, will be required to reveal the clinical effects of these mutations, their incidence in patients with ALL and their role in leukemogenesis.

Citation Format: Vijai Joseph, Michael F. Walsh, Sabine Topka, Gang Wu, Rose B. McGee, Emily Quinn, Hiroto Inaba, Christine Hartford, Ching-Hon Pui, Alberto S. Pappo, Michael Edmonson, Lauren Jacobs, Villano Danylo, Kasmintan Schrader, Pragna Gaddam, Zsofia Stadler, Michael Zhang, Polina Stepensky, Peter Steinherz, James Bussel, M Harit, Michael Weintraub, Akiko Shimamura, Jinghui Zhang, James R. Downing, Kenneth Offit, Kim E. Nichols. Germline mutations in ETV6 confer risk of thrombocytopenia and acute lymphocytic leukemia. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2033. doi:10.1158/1538-7445.AM2015-2033

Natural killer cell therapy in children with relapsed leukemia

BACKGROUND

Novel therapies are needed for children with relapsed or refractory leukemia. We therefore tested the safety and feasibility of haploidentical natural killer cell therapy in this patient population.

PROCEDURE

Twenty-nine children who had relapsed or refractory leukemia were treated with chemotherapy followed by the infusion of haploidentical NK cells. Cohort 1 included 14 children who had not undergone prior allogeneic hematopoietic cell transplantation (HCT), whereas Cohort 2 included 15 children with leukemia that had relapsed after HCT.

RESULTS

Twenty-six (90%) NK donors were KIR mismatched (14 with one KIR and 12 with 2 KIRs). The peak NK chimerism levels were >10% donor in 87% of the evaluable recipients. In Cohort 1, 10 had responsive disease and 12 proceeded to HCT thereafter. Currently, 5 (36%) are alive without leukemia. In Cohort 2, 10 had responsive disease after NK therapy and successfully proceeded to second HCT. At present, 4 (27%) are alive and leukemia-free. The NK cell infusions and the IL-2 injections were well-tolerated.

CONCLUSIONS

NK cell therapy is safe, feasible, and should be further investigated in patients with chemotherapy-resistant leukemia.

Performance of the EuroSCORE II and the Society of Thoracic Surgeons Score in patients undergoing aortic valve replacement for aortic stenosis

Aim. The aim of this study was to evaluate the performance of the new European System for Cardiac Operative Risk Evaluation (EuroSCORE) II and the Society of Thoracic Surgeons (STS) score in patients undergoing aortic valve replacement (AVR) for aortic stenosis (AS). This study also evaluated the performance of the EuroSCORE II in high-risk patients. Methods. Three hundred and six consecutive adult patients underwent AVR with or without coronary artery bypass grafting at our institution from August 2002 to June 2012. The cut-off value of 6% for the EuroSCORE II and 10% for the STS score was used to identify high-risk in this study. Results. Operative mortality was 3.5% (N.=11). The mean expected mortality for all patients was 3.1% (O/E ratio=1.12) for the EuroSCORE II and 5.1% (O/E ratio=0.68) for the STS score. Observed versus expected mortality for the high-risk patients was 17.2% versus 11.9% (O/E ratio=1.44) for the EuroSCORE II (N.=29) and 19.3% versus 18.5% (O/E ratio=1.04) for the STS score (N.=31), and that for the low-risk was 2.1% versus 2.2% (O/E ratio=0.95) for the EuroSCORE II and 1.8% versus 3.5% (O/E ratio=0.51) for the STS score. Discrimination power of the STS score was good (area under the receiver operating characteristics curve [AUC] 0.74), but that of the EuroSCORE II was suboptimal (AUC 0.66). Conclusion. Good calibration ability of the EuroSCORE II for low-risk patients and that of the STS score for high-risk are observed. However, the EuroSCORE II underestimates the operative mortality in high-risk patients and the STS score overestimates the risk in low-risk patients.

Germline ETV6 Mutations Confer Susceptibility to Acute Lymphoblastic Leukemia and Thrombocytopenia

Somatic mutations affecting ETV6 often occur in acute lymphoblastic leukemia (ALL), the most common childhood malignancy. The genetic factors that predispose to ALL remain poorly understood. Here we identify a novel germline ETV6 p. L349P mutation in a kindred affected by thrombocytopenia and ALL. A second ETV6 p. N385fs mutation was identified in an unrelated kindred characterized by thrombocytopenia, ALL and secondary myelodysplasia/acute myeloid leukemia. Leukemic cells from the proband in the second kindred showed deletion of wild type ETV6 with retention of the ETV6 p. N385fs. Enforced expression of the ETV6 mutants revealed normal transcript and protein levels, but impaired nuclear localization. Accordingly, these mutants exhibited significantly reduced ability to regulate the transcription of ETV6 target genes. Our findings highlight a novel role for ETV6 in leukemia predisposition.

Clinical utility of sequential minimal residual disease measurements in the context of risk-based therapy in childhood acute lymphoblastic leukaemia: a prospective study

BACKGROUND

The level of minimal residual disease during remission induction is the most important prognostic indicator in patients with acute lymphoblastic leukaemia (ALL). We aimed to establish the clinical significance of minimal residual disease in a prospective trial that used sequential minimal residual disease measurements to guide treatment decisions.

METHODS

Between June 7, 2000, and Oct 24, 2007, 498 assessable patients with newly diagnosed ALL were enrolled in a clinical trial at St Jude Children's Research Hospital. We provisionally classified the risk of relapse as low, standard, or high according to patients' baseline clinical and laboratory features. Final risk assignment to establish treatment intensity was based mainly on minimal residual disease levels measured on days 19 and 46 of remission induction, and on week 7 of maintenance treatment. Additional measurements of minimal residual disease were made on weeks 17, 48, and 120 (end of treatment). The primary aim was to establish the association between event-free survival and patients' minimal residual disease levels during remission induction and sequentially post-remission. This trial was registered at ClinicalTrials.gov, number NCT00137111.

FINDINGS

Irrespective of the provisional risk classification, 10-year event-free survival was significantly worse for patients with 1% or greater minimal residual disease levels on day 19 compared with patients with lower minimal residual disease levels (69·2%, 95% CI 49·6-82·4, n=36 vs 95·5%, 91·7-97·5, n=244; p<0·001 for the provisional low-risk group and 65·1%, 50·7-76·2, n=56 vs 82·9%, 75·6-88·2, n=142; p=0·01 for the provisional standard-risk group). 12 patients with provisional low-risk ALL and 1% or higher minimal residual disease levels on day 19 but negative minimal residual disease (<0·01%) on day 46 were treated for standard-risk ALL and had a 10-year event-free survival of 88·9% (43·3-98·4). For the 280 provisional low-risk patients, a minimal residual disease level of less than 1% on day 19 predicted a better outcome, irrespective of the minimal residual disease level on day 46. Of provisional standard-risk patients with minimal residual disease of less than 1% on day 19, the 15 with persistent minimal residual disease on day 46 seemed to have an inferior 10-year event-free survival compared with the 126 with negative minimal residual disease (72·7%, 42·5-88·8 vs 84·0%, 76·3-89·4; p=0·06) after receiving the same post-remission treatment for standard-risk ALL. Of patients attaining negative minimal residual disease status after remission induction, minimal residual disease re-emerged in four of 382 studied on week 7, one of 448 at week 17, and one of 437 at week 48; all but one of these six patients died despite additional treatment. By contrast, relapse occurred in only two of the 11 patients who had decreasing minimal residual disease levels between the end of induction and week 7 of maintenance therapy and were treated with chemotherapy alone.

INTERPRETATION

Minimal residual disease levels during remission induction treatment have important prognostic and therapeutic implications even in the context of minimal residual disease-guided treatment. Sequential minimal residual disease monitoring after remission induction is warranted for patients with detectable minimal residual disease.

FUNDING

National Institutes of Health and American Lebanese Syrian Associated Charities.

Utility of early screening magnetic resonance imaging for extensive hip osteonecrosis in pediatric patients treated with glucocorticoids

PURPOSE

Hip osteonecrosis frequently complicates treatment with glucocorticoids. When extensive (affecting ≥ 30% of the epiphyseal surface), 80% of joints collapse within 2 years, so interventions are needed to prevent this outcome.

PATIENTS AND METHODS

This prospective cohort magnetic resonance imaging (MRI) screening study included all consecutive children treated for acute lymphoblastic leukemia on a single protocol. Hip MRI was performed at 6.5 and 9 months from diagnosis (early screening) and at completion of chemotherapy (final evaluation) to determine whether screening could identify extensive hip osteonecrosis before symptom development.

RESULTS

Of 498 patients, 462 underwent screening MRI. Extensive asymptomatic osteonecrosis was identified by early screening in 26 patients (41 hips); another four patients (seven hips) were detected after the screening period, such that screening sensitivity was 84.1% and specificity was 99.4%. The number of joints screened to detect one lesion was 20.1 joints for all patients, 4.4 joints for patients older than 10 years, and 198 joints for patients ≤ 10 years old (P < .001). Of the 40 extensive lesions in patients older than 10 years, 19 required total hip arthroplasty and none improved. Of eight extensive lesions in younger patients, none required arthroplasty and four improved.

CONCLUSION

In patients age 10 years old or younger who require prolonged glucocorticoid therapy, screening for extensive hip osteonecrosis is unnecessary because their risk is low and lesions tend to heal. In children older than 10 years, early screening successfully identifies extensive asymptomatic lesions in patients who would be eligible for studies of interventions to prevent or delay joint collapse.

The role of FDG-PET/CT in the evaluation of residual disease in paediatric non-Hodgkin lymphoma

(18) F-labelled-fluorodeoxyglucose positron emission tomography (FDG-PET) findings are challenging to interpret for residual disease versus complete response in paediatric patients with non-Hodgkin lymphoma (NHL). A biopsy is often warranted to confirm the presence or absence of viable tumour if there is clinical or radiographic evidence of residual disease. In this study, we compared conventional imaging and FDG-PET/computerized tomography (CT) findings with biopsy results in 18 children with NHL. Our goal was to provide additional data to establish more reliable criteria for response evaluation. Residual disease was suspected after conventional imaging alone in eight patients, after FDG-PET/CT alone in three and after both modalities in seven patients. Biopsy confirmed the presence of viable tumour in two patients. Two additional patients experienced progressive disease or relapse. The sensitivity and negative predictive value of FDG-PET/CT using the London criteria to indicate residual tumour detectable by biopsy were 100%, but specificity was low (60%), as was the positive predictive value (25%). Thus, in this study, a negative FDG-PET/CT finding was a good indicator of complete remission. However, because false-positive FDG-PET/CT findings are common, biopsy and close monitoring are required for accurate determination of residual disease in individual patients.

Prognostic factors in children with acute myeloid leukaemia and excellent response to remission induction therapy

Minimal residual disease (MRD) is a strong prognostic factor in children and adolescents with acute myeloid leukaemia (AML) but nearly one-quarter of patients who achieve MRD-negative status still relapse. The adverse prognostic factors among MRD-negative patients remain unknown. We analysed the AML02 study cohort to identify demographic and genetic prognostic factors. Among the presenting features, certain 11q23 abnormalities, such as t(6;11) and t(10;11), acute megakaryoblastic leukaemia without the t(1;22), and age ≥10 years were associated with inferior outcome in patients who had MRD-negative status after either remission induction I or II. By contrast, those with rearrangement of CBF genes had superior outcome. Our study identifies patient populations for whom close post-remission MRD monitoring to detect and treat emerging relapse and adjustment in treatment intensity might be indicated.

Skeletal, neuromuscular and fitness impairments among children with newly diagnosed acute lymphoblastic leukemia

This study describes skeletal, neuromuscular and fitness impairments among 109 children (median age 10 [range 4-18] years, 65.1% male, 63.3% white) with acute lymphoblastic leukemia (ALL). Outcomes were measured 7-10 days after diagnosis and compared to age- and sex-specific expected values. Associations between function and health-related quality of life (HRQL) were evaluated with logistic regression. Children with ALL had sub-optimal bone mineral density (BMD) Z-score/height (mean ± standard error: - 0.53 ± 0.16 vs. 0.00 ± 0.14, p < 0.01), body mass index percentile (57.6 ± 3.15 vs. 50.0 ± 3.27%, p = 0.02), quadriceps strength (201.9 ± 8.3 vs. 236.1 ± 5.4 N, p < 0.01), 6 min walk distance (385.0 ± 13.1 vs. 628.2 ± 7.1 m, p < 0.001) and Bruininks-Oseretsky Test of Motor Proficiency scores (23 ± 2.5 vs. 50 ± 3.4%, p < 0.01). Quadriceps weakness was associated with a 20.9-fold (95% confidence interval 2.5-173.3) increase in poor physical HRQL. Children with newly diagnosed ALL have weakness and poor endurance and may benefit from early rehabilitation that includes strengthening and aerobic conditioning.

Feasibility, efficacy, and adverse effects of outpatient antibacterial prophylaxis in children with acute myeloid leukemia

BACKGROUND

Intensive chemotherapy for pediatric acute myeloid leukemia incurs the risk of infectious complications, but the benefits of antibiotic prophylaxis remain unclear.

METHODS

In the current study, among 103 children treated on the AML02 protocol between October 2002 and October 2008 at St. Jude Children's Research Hospital, the authors retrospectively assessed the effect of antibiotic prophylaxis on the frequency of febrile neutropenia, clinically or microbiologically confirmed infections (including bacteremia), and antibiotic resistance, as well as on the results of nasal and rectal surveillance cultures. Initially, patients received no prophylaxis or oral cephalosporin (group A). The protocol was then amended to administer intravenous cefepime alone or intravenous vancomycin plus either oral cephalosporin, oral ciprofloxacin, or intravenous cefepime (group B).

RESULTS

There were 334 infectious episodes. Patients in group A had a significantly greater frequency of documented infections and bacteremia (both P < .0001) (including gram-positive and gram-negative bacteremia; P = .0003 and .001, respectively) compared with patients in group B, especially viridans streptococcal bacteremia (P = .001). The incidence of febrile neutropenia without documented infection was not found to be different between the 2 groups. Five cases of bacteremia with vancomycin-resistant enterococci (VRE) occurred in group B (vs none in group A), without related mortality. Two of these cases were preceded by positive VRE rectal surveillance cultures.

CONCLUSIONS

Outpatient intravenous antibiotic prophylaxis is feasible in children with acute myeloid leukemia and reduces the frequency of documented infection but not of febrile neutropenia. Despite the emergence of VRE bacteremia, the benefits favor antibiotic prophylaxis. Creative approaches to shorten the duration of prophylaxis and thereby minimize resistance should be explored.

Definition of cure in childhood acute myeloid leukemia

BACKGROUND

A better understanding of when cure can be declared in childhood acute myeloid leukemia (AML) would reduce anxiety and improve quality of life of AML survivors. The authors determined the likelihood that patients with AML would maintain long-term remission after the completion of therapy.

METHODS

The cumulative risk of relapse, the time to relapse, event-free survival, and overall survival were analyzed for 604 patients with AML who were enrolled in 7 successive clinical trials divided into 3 treatment eras (1976-1991, 1991-1997, and 2002-2008).

RESULTS

The median time to relapse did not change over time (0.93 years vs 0.76 years vs 0.8 years, respectively, for each consecutive era; P = .22), but the risk of relapse decreased significantly (5-year cumulative incidence of relapse: 52.6% ± 3.1% vs 31.5% ± 3.9% vs 22% ± 3%, respectively, for each consecutive era; P < .001). Among patients who were in remission 4 years from diagnosis, the probabilities of relapse were 1.7%, 2.9%, and 0.9%, respectively, for each consecutive era. In the most recent era, all but 1 of 44 relapses occurred within 4 years of diagnosis.

CONCLUSIONS

Children with AML who receive treatment with contemporary therapy and remain in remission 4 years from diagnosis probably are cured. Although late relapses and late deaths from other causes are rare, long-term follow-up of survivors is necessary for the timely management of late adverse effects.