Acute Promyelocytic Leukemia With Torque Teno Mini Virus::RARA Fusion: An Approach to Screening and Diagnosis.

Acute promyelocytic leukemia (APL) with variant RARA translocation is linked to over 15 partner genes. Recent publications encompassing 6 cases have expanded the spectrum of RARA partners to torque teno mini virus (TTMV). This entity is likely underrecognized due to the lack of clinician and pathologist familiarity, inability to detect the fusion using routine testing modalities, and informatic challenges in its recognition within next-generation sequencing (NGS) data. We describe a clinicopathologic approach and provide the necessary tools to screen and diagnose APL with TTMV::RARA using existing clinical DNA- or RNA-based NGS assays, which led to the identification of 4 cases, all without other known cytogenetic/molecular drivers. One was identified prospectively and 3 retrospectively, including 2 from custom automated screening of multiple data sets (50,257 cases of hematopoietic malignancy, including 4809 acute myeloid leukemia/myeloid sarcoma/APL cases). Two cases presented as myeloid sarcoma, including 1 with multiple relapses after acute myeloid leukemia-type chemotherapy and hematopoietic stem cell transplant. Two cases presented as leukemia, had a poor response to induction chemotherapy, but achieved remission upon reinduction (including all-trans retinoic acid in 1 case) and subsequent hematopoietic stem cell transplant. Neoplastic cells demonstrated features of APL including frequent azurophilic granules and dim/absent CD34 and HLA-DR expression. RARA rearrangement was not detected by karyotype or fluorescent in situ hybridization. Custom analysis of NGS fusion panel data identified TTMV::RARA rearrangements and, in the prospectively identified case, facilitated monitoring in sequential bone marrow samples. APL with TTMV::RARA is a rare leukemia with a high rate of treatment failure in described cases. The diagnosis should be considered in leukemias with features of APL that lack detectable RARA fusions and other drivers, and may be confirmed by appropriate NGS tests with custom informatics. Incorporation of all-trans retinoic acid may have a role in treatment but requires accurate recognition of the fusion for appropriate classification as APL.

Single-cell RNA-seq reveals developmental plasticity with coexisting oncogenic states and immune evasion programs in ETP-ALL.

Lineage plasticity and stemness have been invoked as causes of therapy resistance in cancer, because these flexible states allow cancer cells to dedifferentiate and alter their dependencies. We investigated such resistance mechanisms in relapsed/refractory early T-cell progenitor acute lymphoblastic leukemia (ETP-ALL) carrying activating NOTCH1 mutations via full-length single-cell RNA sequencing (scRNA-seq) of malignant and microenvironmental cells. We identified 2 highly distinct stem-like states that critically differed with regard to cell cycle and oncogenic signaling. Fast-cycling stem-like leukemia cells demonstrated Notch activation and were effectively eliminated in patients by Notch inhibition, whereas slow-cycling stem-like cells were Notch independent and rather relied on PI3K signaling, likely explaining the poor efficacy of Notch inhibition in this disease. Remarkably, we found that both stem-like states could differentiate into a more mature leukemia state with prominent immunomodulatory functions, including high expression of the LGALS9 checkpoint molecule. These cells promoted an immunosuppressive leukemia ecosystem with clonal accumulation of dysfunctional CD8+ T cells that expressed HAVCR2, the cognate receptor for LGALS9. Our study identified complex interactions between signaling programs, cellular plasticity, and immune programs that characterize ETP-ALL, illustrating the multidimensionality of tumor heterogeneity. In this scenario, combination therapies targeting diverse oncogenic states and the immune ecosystem seem most promising to successfully eliminate tumor cells that escape treatment through coexisting transcriptional programs.

Predictors of thrombosis in children receiving therapy for acute lymphoblastic leukemia: Results from Dana-Farber Cancer Institute ALL Consortium trial 05-001.

BACKGROUND/OBJECTIVES: Although thromboembolism (TE) is a serious complication in patients with acute lymphoblastic leukemia (ALL), thromboprophylaxis is not commonly used due to the inherent bleeding risk in this population. Identifying prothrombotic risk factors will help target thromboprophylaxis to those at highest thrombotic risk. We aimed to define predictors and the impact of TE on ALL outcome in children (1-18 years) treated on the Dana-Farber Cancer Institute ALL 05-001 trial. METHODS: Clinical and laboratory data including TE events were prospectively collected. PCR-based allelic discrimination assay identified single-nucleotide polymorphisms (SNP) for prothrombin G20210A (rs1799963) and Factor V G1691A (rs6025). Univariate and multivariable competing risk regression models evaluated the effect of diagnostic clinical (age, sex, body mass index, ALL-immunophenotype, risk group) and laboratory variables (presenting leukocyte count, blood group, SNPs) on the cumulative incidence of TE. Cox regression modeling explored the impact of TE on survival. RESULTS: Of 794 patients [median age 4.97 (range, 1.04-17.96) years; males 441], 100 developed TE; 25-month cumulative incidence 13.0% (95% CI, 10.7%-15.5%). Univariate analyses identified older age (≥10 years), presenting leucocyte count, T-ALL, high-risk ALL, and non-O blood group as risk factors. Age and non-O blood group were independent predictors of TE on multivariable regression; the blood group impact being most evident in patients 1-5 years of age (P = 0.011). TE did not impact survival. Induction TE was independently associated with induction failure (OR 6.45; 95% CI, 1.64-25.47; P = 0.008). CONCLUSION: We recommend further evaluation of these risk factors and consideration of thromboprophylaxis for patients ≥10 years (especially those ≥15 years) when receiving asparaginase.

Impact of acute lymphoblastic leukemia induction therapy: findings from metabolomics on non-fasted plasma samples from a biorepository.

INTRODUCTION: Acute lymphoblastic leukemia (ALL) is among the most common cancers in children. With improvements in combination chemotherapy regimens, the overall survival has increased to over 90%. However, the current challenge is to mitigate adverse events resulting from the complex therapy. Several chemotherapies intercept cancer metabolism, but little is known about their collective role in altering host metabolism. OBJECTIVES: We profiled the metabolomic changes in plasma of ALL patients initial- and post- induction therapy. METHODS: We exploited a biorepository of non-fasted plasma samples derived from the Dana Farber Cancer Institute ALL Consortium; these samples were obtained from 50 ALL patients initial- and post-induction therapy. Plasma metabolites and complex lipids were analyzed by high resolution tandem mass spectrometry and differential mobility tandem mass spectrometry. Data were analyzed using a covariate-adjusted regression model with multiplicity adjustment. Pathway enrichment analysis and co-expression network analysis were performed to identify unique clusters of molecules. RESULTS: More than 1200 metabolites and complex lipids were identified in the total of global metabolomics and lipidomics platforms. Over 20% of those molecules were significantly altered. In the pathway enrichment analysis, lipids, particularly phosphatidylethanolamines (PEs), were identified. Network analysis indicated that the bioactive fatty acids, docosahexaenoic acid (DHA)-containing (22:6) triacylglycerols (TAGs), were decreased in the post-induction therapy. CONCLUSION: Metabolomic profiling in ALL patients revealed a large number of alterations following induction chemotherapy. In particular, lipid metabolism was substantially altered. The changes in metabolites and complex lipids following induction therapy could provide insight into the adverse events experienced by ALL patients.

Identification of prognostic factors in childhood T-cell acute lymphoblastic leukemia: Results from DFCI ALL Consortium Protocols 05-001 and 11-001.

BACKGROUND/OBJECTIVES: While outcomes for pediatric T-cell acute lymphoblastic leukemia (T-ALL) are favorable, there are few widely accepted prognostic factors, limiting the ability to risk stratify therapy. DESIGN/METHODS: Dana-Farber Cancer Institute (DFCI) Protocols 05-001 and 11-001 enrolled pediatric patients with newly diagnosed B- or T-ALL from 2005 to 2011 and from 2012 to 2015, respectively. Protocol therapy was nearly identical for patients with T-ALL (N = 123), who were all initially assigned to the high-risk arm. End-induction minimal residual disease (MRD) was assessed by reverse transcription polymerase chain reaction (RT-PCR) or next-generation sequencing (NGS), but was not used to modify postinduction therapy. Early T-cell precursor (ETP) status was determined by flow cytometry. Cases with sufficient diagnostic DNA were retrospectively evaluated by targeted NGS of known genetic drivers of T-ALL, including Notch, PI3K, and Ras pathway genes. RESULTS: The 5-year event-free survival (EFS) and overall survival (OS) for patients with T-ALL was 81% (95% CI, 73-87%) and 90% (95% CI, 83-94%), respectively. ETP phenotype was associated with failure to achieve complete remission, but not with inferior OS. Low end-induction MRD (<10-4 ) was associated with superior disease-free survival (DFS). Pathogenic mutations of the PI3K pathway were mutually exclusive of ETP phenotype and were associated with inferior 5-year DFS and OS. CONCLUSIONS: Together, our findings demonstrate that ETP phenotype, end-induction MRD, and PI3K pathway mutation status are prognostically relevant in pediatric T-ALL and should be considered for risk classification in future trials. DFCI Protocols 05-001 and 11-001 are registered at www.clinicaltrials.gov as NCT00165087 and NCT01574274, respectively.

Recurrent and novel USP6 fusions in cranial fasciitis identified by targeted RNA sequencing.

Cranial fasciitis is a benign myofibroproliferative lesion of the scalp and underlying bones typically occurring in the pediatric population. Histologically, it is characterized by loose fascicles of stellate cells in a fibromyxoid background, findings similar to those described in the closely related variant nodular fasciitis. Previously characterized as a reactive process, the identification of USP6 translocations in over 90% of nodular fasciitis cases prompted their reclassification as a clonal neoplastic process. Unlike nodular fasciitis, the molecular underpinnings of cranial fasciitis are less clear. While a subset of cranial fasciitis has been associated with Wnt/ß-catenin pathway dysregulation, recent case reports suggest that this entity may also harbor USP6 fusions, a finding we sought to further investigate. We identified fifteen archival cases of cranial fasciitis, five females and ten males ranging in age from 3 months to 9 years (median 11 months), composed of formalin-fixed paraffin-embedded and fresh frozen tissues (11 and 4 cases respectively). Samples were evaluated on an RNA-based targeted sequencing panel targeting genes recurrently rearranged in neoplasia, including USP6. Five of fifteen cases (33%) were positive for USP6 rearrangements predicted to result in the fusion of the entire USP6 coding region to the promoter of the 5' partner, (three of which were novel):  two SERPINH1-USP6 (novel) and one each of COL3A1-USP6 (novel), SPARC-USP6, and MYH9-USP6. These results demonstrate the recurrent nature of USP6 rearrangements in cranial fasciitis, and highlight the success of targeted RNA sequencing in identifying known and novel fusion partners. The identification of USP6 promoter-swapping rearrangements is helpful in understanding the underlying biology of cranial fasciitis, and reinforces its biologic relationship to nodular fasciitis. Targeted RNA sequencing is a helpful tool in diagnosing this pseudosarcomatous lesion.

Recurrent RET gene fusions in paediatric spindle mesenchymal neoplasms.

AIMS: The classification of paediatric spindle mesenchymal tumours is evolving, and the spectrum of so-called 'infantile fibrosarcoma' has expanded to include tumours with NTRK, BRAF and MET gene fusions. RET-rearranged paediatric spindle cell neoplasms are an emerging group; there is sparse literature on their clinical, pathological and genetic features, and their nosological place in the canon of soft tissue tumours is uncertain. In this study, we report five RET-rearranged paediatric spindle cell tumours with fusion partners MYH10, KIAA1217 and CLIP2. METHODS AND RESULTS: The tumours occurred in the pelvic region, paraspinal region, kidney and subcutaneous tissue of hand and abdomen. The patients' ages ranged from 6 months to 13 years (median 1 year). The tumours were composed of monomorphic spindle cells arranged in a fascicular pattern. Lesional cells had minimally atypical ovoid or tapered nuclei and pale cytoplasm with indistinct borders. Necrosis was not identified. Mitoses numbered three to 12 per 10 high-power field. Cases showed inconsistent and variable expression of S100, CD34 and SMA. Clinical behaviour ranged from small lesions potentially cured by simple resection to large lesions exhibiting metastasis, but responsive to kinase inhibitor therapy. CONCLUSIONS: Our findings help to define RET-rearranged spindle cell tumours. Although it is likely that these tumours comprise part of the morphological and clinical spectrum of infantile fibrosarcoma (IFS), identification of RET gene alteration is important for its unique therapeutic implications.

Making the most of small samples: Optimization of tissue allocation of pediatric solid tumors for clinical and research use.

INTRODUCTION: Tissue from pediatric solid tumors is in high demand for use in high-impact research studies, making the allocation of tissue from an anatomic pathology laboratory challenging. We designed, implemented, and assessed an interdepartmental process to optimize tissue allocation of pediatric solid tumors for both clinical care and research. METHODS: Oncologists, pathologists, surgeons, interventional radiologists, pathology technical staff, and clinical research coordinators participated in the workflow design. Procedures were created to address patient identification and consent, prioritization of protocols, electronic communication of requests, tissue preparation, and distribution. Pathologists were surveyed about the value of the new workflow. RESULTS: Over a 5-year period, 644 pediatric solid tumor patients consented to one or more studies requesting archival or fresh tissue. Patients had a variety of tumor types, with many rare and singular diagnoses. Sixty-seven percent of 1768 research requests were fulfilled. Requests for archival tissue were fulfilled at a significantly higher rate than those for fresh tissue (P > .001), and requests from resection specimens were fulfilled at a significantly higher rate than those from biopsies (P > .0001). In an anonymous survey, seven of seven pathologists reported that the process had improved since the introduction of the electronic communication model. CONCLUSIONS: A collaborative and informed model for tissue allocation is successful in distributing archival and fresh tissue for clinical research studies. Our workflows and policies have gained pathologists' approval and streamlined our processes. As clinical and research programs evolve, a thoughtful tissue allocation process will facilitate ongoing research.

High NPM1 mutant allele burden at diagnosis correlates with minimal residual disease at first remission in de novo acute myeloid leukemia.

Acute myeloid leukemia (AML) with mutated NPM1 is a newly recognized separate entity in the revised 2016 WHO classification, and is associated with a favorable prognosis. While previous studies have evaluated NPM1 in a binary fashion, we recently demonstrated a significant independent negative prognostic effect of high NPM1 mutant allele burden (VAF) at diagnosis in a cohort of de novo AML patients. Although the importance of minimal residual disease (MRD) monitoring in NPM1-mutated AML has been well characterized, the potential relationship between diagnostic allele burden and MRD is unknown. We retrospectively evaluated for MRD at first remission (CR1). We used either next-generation sequencing (NGS) [n = 71], and/or immunohistochemistry (IHC) for mutant NPM1 (NPM1c) [n = 60], in a subset of patients from our recently examined cohort. We identified a statistically significant positive correlation between the VAF at diagnosis, and at CR1 (Spearman r = 0.4, P = .006), and enrichment for MRD in high diagnostic VAF patients (P = .05), as previously defined. IHC-positivity also correlated significantly with a higher median diagnostic NPM1 VAF (0.42 vs 0.39, P = .02), and with the VAF at CR1 (Spearman r = 0.7, P = .003). In multivariable analyses, both high diagnostic VAF (P = .003) and MRD (P = .02) were independent predictors of shorter event-free survival (EFS). Our findings suggest a relationship between the NPM1 mutant allele burden at diagnosis, and the presence of MRD at first remission. Our findings support IHC as a potentially useful adjunctive tool for disease monitoring.

Recurrent EML4-NTRK3 fusions in infantile fibrosarcoma and congenital mesoblastic nephroma suggest a revised testing strategy.

Infantile fibrosarcoma and congenital mesoblastic nephroma are tumors of infancy traditionally associated with the ETV6-NTRK3 gene fusion. However, a number of case reports have identified variant fusions in these tumors. In order to assess the frequency of variant NTRK3 fusions, and in particular whether the recently identified EML4-NTRK3 fusion is recurrent, 63 archival cases of infantile fibrosarcoma, congenital mesoblastic nephroma, mammary analog secretory carcinoma and secretory breast carcinoma (tumor types that are known to carry recurrent ETV6-NTRK3 fusions) were tested with NTRK3 break-apart FISH, EML4-NTRK3 dual fusion FISH, and targeted RNA sequencing. The EML4-NTRK3 fusion was identified in two cases of infantile fibrosarcoma (one of which was previously described), and in one case of congenital mesoblastic nephroma, demonstrating that the EML4-NTRK3 fusion is a recurrent genetic event in these related tumors. The growing spectrum of gene fusions associated with infantile fibrosarcoma and congenital mesoblastic nephroma along with the recent availability of targeted therapies directed toward inhibition of NTRK signaling argue for alternate testing strategies beyond ETV6 break-apart FISH. The use of either NTRK3 FISH or next-generation sequencing will expand the number of cases in which an oncogenic fusion is identified and facilitate optimal diagnosis and treatment for patients.

Pediatric-type nodal follicular lymphoma: a biologically distinct lymphoma with frequent MAPK pathway mutations.

Pediatric-type nodal follicular lymphoma (PTNFL) is a variant of follicular lymphoma (FL) characterized by limited-stage presentation and invariably benign behavior despite often high-grade histological appearance. It is important to distinguish PTNFL from typical FL in order to avoid unnecessary treatment; however, this distinction relies solely on clinical and pathological criteria, which may be variably applied. To define the genetic landscape of PTNFL, we performed copy number analysis and exome and/or targeted sequencing of 26 PTNFLs (16 pediatric and 10 adult). The most commonly mutated gene in PTNFL was MAP2K1, encoding MEK1, with a mutation frequency of 43%. All MAP2K1 mutations were activating missense mutations localized to exons 2 and 3, which encode negative regulatory and catalytic domains, respectively. Missense mutations in MAPK1 (2/22) and RRAS (1/22) were identified in cases that lacked MAP2K1 mutations. The second most commonly mutated gene in PTNFL was TNFRSF14, with a mutation frequency of 29%, similar to that seen in limited-stage typical FL (P = .35). PTNFL was otherwise genomically bland and specifically lacked recurrent mutations in epigenetic modifiers (eg, CREBBP, KMT2D). Copy number aberrations affected a mean of only 0.5% of PTNFL genomes, compared with 10% of limited-stage typical FL genomes (P < .02). Importantly, the mutational profiles of PTNFLs in children and adults were highly similar. Together, these findings define PTNFL as a biologically and clinically distinct indolent lymphoma of children and adults characterized by a high prevalence of MAPK pathway mutations and a near absence of mutations in epigenetic modifiers.

Genomic and clinical characterization of B/T mixed phenotype acute leukemia reveals recurrent features and T-ALL like mutations.

The B/T subtype of mixed phenotype acute leukemia (B/T MPAL) is defined by co-expression of antigens of both B- and T-cell lineages on leukemic blasts. Although it has been suggested that multilineage antigen expression portends poor response to chemotherapy, the clinical characteristics and driver mutations that underlie the pathogenesis of this rare subtype of acute leukemia are scarcely known. We identified nine cases of B/T MPAL from multiple institutions and correlated clinical and immunophenotypic findings with next-generation sequencing data. We report that B/T MPAL commonly presents with lymphadenopathy in adolescence and young adulthood. While the tumors have diverse cytogenetic and genomic perturbations, recurrent acquired aberrations include mutations in the putative transcriptional regulator PHF6 and the JAK-STAT and Ras signaling pathways. Alterations were also identified in genes encoding hematopoietic transcription factors, cell cycle regulators/tumor suppressors, and chromatin modifying enzymes. The genomic landscape of B/T MPAL strongly resembles that of T-ALL subgroups associated with early developmental arrest, while genetic alterations that are common in B-ALL were rarely seen. Two-thirds of the patients responded to ALL-based chemotherapy with or without stem cell transplantation. Our observations lay the groundwork for further study of the unique biology and clinical trajectory of B/T MPAL.

Phase I trial of the mTOR inhibitor everolimus in combination with multi-agent chemotherapy in relapsed childhood acute lymphoblastic leukemia.

BACKGROUND: We sought to determine the feasibility of co-administering everolimus with a four-drug reinduction in children and adolescents with acute lymphoblastic leukemia (ALL) experiencing a first marrow relapse. PROCEDURE: This phase I study tested everolimus with vincristine, prednisone, pegaspargase and doxorubicin in patients with marrow relapse occurring >18 months after first complete remission (CR). The primary aim was to identify the maximum tolerated dose of everolimus. Three dose levels (DLs) were tested during dose escalation (2, 3, and 5 mg/m2 /day). Additional patients were enrolled at the 3- and 5 mg/m2 /day DLs to further evaluate toxicity (dose expansion). RESULTS: Thirteen patients enrolled during dose escalation and nine during dose expansion. During dose escalation, one dose-limiting toxicity occurred (grade 4 hyperbilirubinemia) in six evaluable patients at DL3 (5 mg/m2 /day). The most common grade ≥3 adverse events were febrile neutropenia, infections, transaminitis, hyperbilirubinemia, and hypophosphatemia. Two of the 12 patients treated at DL3 developed Rothia mucilaginosa meningitis. Nineteen patients (86%) achieved a second CR (CR2). Of those, 13 (68%) had a low end-reinduction minimal residual disease (MRD) level (≤10-3 by polymerase chain reaction-based assay). The CR2 rate for patients with B-cell ALL treated at DL3 (n = 12) was 92%; 82% of these patients had low MRD. CONCLUSIONS: Everolimus combined with four-drug reinduction chemotherapy was generally well tolerated and associated with favorable rates of CR2 and low end-reinduction MRD. The recommended phase 2 dose of everolimus given in combination with a four-drug reinduction is 5 mg/m2 /day. This promising combination should be further evaluated in a larger patient cohort.

Outcome of children and adolescents with Down syndrome treated on Dana-Farber Cancer Institute Acute Lymphoblastic Leukemia Consortium protocols 00-001 and 05-001.

BACKGROUND: Children and adolescents with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) are reported to have increased relapse rates and therapy-related mortality (TRM). Treatment regimens for DS-ALL patients often include therapy modifications. Dana-Farber Cancer Institute (DFCI) ALL Consortium protocols have used same risk-stratified treatment for patients with and without DS. PROCEDURES: We compared clinical and outcome data of DS (n = 38) and non-DS (n = 1,248) patients enrolled on two consecutive DFCI ALL trials 00-001 (2000-2004) and 05-001 (2005-2011) with similar risk adapted therapy regardless of DS status. RESULTS: There was no difference in demographic or presenting clinical features between two groups except absence of T-cell phenotype and lower frequency of hyperdiploidy in DS-ALL group. All DS-ALL patients achieved complete remission; four relapsed and one subsequently died. There was no TRM in DS-ALL patients. DS-ALL patients had significantly higher rates of mucositis (52% vs. 12%, p < 0.001), non-CNS thrombosis (18% vs. 8%; p = 0.036), and seizure (16% vs. 5%, p = 0.010). Compared to non-DS-ALL patients, DS-ALL patients had a higher incidence of infections during all therapy phases. The 5-year event-free and overall survival rates of DS-ALL patients were similar to non-DS-ALL patients (91% [95% confidence interval (CI), 81-100] vs. 84% [95% CI, 82-86]; 97% [95% CI, 92-100] vs. 91% [95% CI, 90-93]). CONCLUSION: The low rates of relapse and TRM indicate that uniform risk-stratified therapy for DS-ALL and non-DS-ALL patients on DFCI ALL Consortium protocols was safe and effective, although the increased rate of toxicity in the DS-ALL patients highlights the importance of supportive care during therapy.

c-Myc inhibition prevents leukemia initiation in mice and impairs the growth of relapsed and induction failure pediatric T-ALL cells.

Although prognosis has improved for children with T-cell acute lymphoblastic leukemia (T-ALL), 20% to 30% of patients undergo induction failure (IF) or relapse. Leukemia-initiating cells (LICs) are hypothesized to be resistant to chemotherapy and to mediate relapse. We and others have shown that Notch1 directly regulates c-Myc, a known regulator of quiescence in stem and progenitor populations, leading us to examine whether c-Myc inhibition results in efficient targeting of T-ALL-initiating cells. We demonstrate that c-Myc suppression by small hairpin RNA or pharmacologic approaches prevents leukemia initiation in mice by eliminating LIC activity. Consistent with its anti-LIC activity in mice, treatment with the BET bromodomain BRD4 inhibitor JQ1 reduces C-MYC expression and inhibits the growth of relapsed and IF pediatric T-ALL samples in vitro. These findings demonstrate a critical role for c-Myc in LIC maintenance and provide evidence that MYC inhibition may be an effective therapy for relapsed/IF T-ALL patients.

Intravenous pegylated asparaginase versus intramuscular native Escherichia coli L-asparaginase in newly diagnosed childhood acute lymphoblastic leukaemia (DFCI 05-001): a randomised, open-label phase 3 trial.

BACKGROUND: l-asparaginase is a universal component of treatment for childhood acute lymphoblastic leukaemia, and is usually administered intramuscularly. Pegylated Escherichia coli asparaginase (PEG-asparaginase) has a longer half-life and is potentially less immunogenic than the native Escherichia coli (E coli) preparation, and can be more feasibly administered intravenously. The aim of the Dana-Farber Cancer Institute Acute Lymphoblastic Leukaemia Consortium Protocol 05-001 (DFCI 05-001) was to compare the relative toxicity and efficacy of intravenous PEG-asparaginase and intramuscular native E colil-asparaginase in children with newly diagnosed acute lymphoblastic leukaemia. METHODS: DFCI 05-001 enrolled patients aged 1-18 years with newly diagnosed acute lymphoblastic leukaemia from 11 consortium sites in the USA and Canada. Patients were assigned to an initial risk group on the basis of their baseline characteristics and then underwent 32 days of induction therapy. Those who achieved complete remission after induction therapy were assigned to a final risk group and were eligible to participate in a randomised comparison of intravenous PEG-asparaginase (15 doses of 2500 IU/m(2) every 2 weeks) or intramuscular native E colil-asparaginase (30 doses of 25 000 IU/m(2) weekly), beginning at week 7 after study entry. Randomisation (1:1) was unmasked, and was done by a statistician-generated allocation sequence using a permuted blocks algorithm (block size of 4), stratified by final risk group. The primary endpoint of the randomised comparison was the overall frequency of asparaginase-related toxicities (defined as allergy, pancreatitis, and thrombotic or bleeding complications). Predefined secondary endpoints were disease-free survival, serum asparaginase activity, and quality of life during therapy as assessed by PedsQL surveys. All analyses were done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00400946. FINDINGS: Between April 22, 2005, and Feb 12, 2010, 551 eligible patients were enrolled. 526 patients achieved complete remission after induction, of whom 463 were randomly assigned to receive intramuscular native E colil-asparaginase (n=231) or intravenous PEG-asparaginase (n=232). The two treatment groups did not differ significantly in the overall frequency of asparaginase-related toxicities (65 [28%] of 232 patients in the intravenous PEG-asparaginase group vs 59 [26%] of 231 patients in the intramuscular native E colil-asparaginase group, p=0·60), or in the individual frequency of allergy (p=0·36), pancreatitis (p=0·55), or thrombotic or bleeding complications (p=0·26). Median follow-up was 6·0 years (IQR 5·0-7·1). 5-year disease-free survival was 90% (95% CI 86-94) for patients assigned to intravenous PEG-asparaginase and 89% (85-93) for those assigned to intramuscular native E colil-asparaginase (p=0·58). The median nadir serum asparaginase activity was significantly higher in patients who received intravenous PEG-asparaginase than in those who received intramuscular native E colil-asparaginase. Significantly more anxiety was reported by both patients and parent-proxy in the intramuscular native E colil-asparaginase group than in the intravenous PEG-asparaginase group. Scores for other domains were similar between the groups. The most common grade 3 or worse adverse events were bacterial or fungal infections (47 [20%] of 232 in the intravenous PEG-asparaginase group vs 51 [22%] of 231 patients in the intramuscular E colil-asparaginase group) and asparaginase-related allergic reactions (14 [6%] vs 6 [3%]). INTERPRETATION: Intravenous PEG-asparaginase was not more toxic than, was similarly efficacious to, and was associated with decreased anxiety compared with intramuscular native E colil-asparaginase, supporting its use as the front-line asparaginase preparation in children with newly diagnosed acute lymphoblastic leukaemia. FUNDING: National Cancer Institute and Enzon Pharmaceuticals.

Pediatric aplastic anemia and refractory cytopenia: A retrospective analysis assessing outcomes and histomorphologic predictors.

Pediatric acquired aplastic anemia (AA) is a bone marrow disorder that is difficult to distinguish from inherited bone marrow failure syndromes and hypocellular refractory cytopenia of childhood (RCC). Historically, patients with hypocellular RCC have been given the diagnosis of AA. To assess the clinical and histologic distinction between RCC and AA, we performed a retrospective analysis of 149 patients previously diagnosed with AA between 1976 and 2010. We evaluated event free survival (EFS), overall survival (OS), response rates to immunosuppressive therapy, treatment-related toxicities and clonal evolution. The 5-year EFS and OS were 50.8% ± 5.5% and 73.1% ± 4.7%, respectively. Patients with very severe AA had worse OS compared to patients with severe and moderately severe AA. Seventy-two patients had diagnostic pathology specimens available for review. Three pediatric hematopathologists reviewed and reclassified these specimens as AA, RCC or Other based on 2008 WHO Criteria. The concordance between pathologists in the diagnosis of AA or RCC was modest. RCC was associated with a trend toward improved OS and EFS and was not prognostic of immunosuppression therapy treatment failure. There was a low rate of clonal evolution exclusively associated with moderately severe AA. Our findings indicate that a diagnosis of RCC is difficult to establish with certainty and does not predict outcomes, calling into question the reproducibility and clinical significance of the RCC classification and warranting further studies.

Imaging findings in children with proliferative disorders following multivisceral transplantation.

BACKGROUND: Multivisceral transplantation represents an important treatment option for children with intestinal failure. The attendant immunosuppression can lead to a spectrum of cellular proliferations including benign and malignant smooth muscle tumors and lymphoproliferative disorders, many related to cellular dysregulation from Epstein-Barr virus infection. OBJECTIVE: The purpose of this study is to investigate the rates of post-transplantation proliferative disorders among children with multivisceral transplantation and to characterize the imaging and pathological features of these disorders. MATERIALS AND METHODS: We identified all consecutive children who underwent multivisceral transplant from August 2004 to October 2011 with at least 27 months of clinical and imaging follow-up. We reviewed medical records to determine the underlying causes of the multivisceral transplant, age at transplantation, onset of neoplasm development, and outcome. Two pediatric radiologists reviewed all imaging studies independently and diagnosis of disease was made by consensus interpretation. Pathological specimens were reviewed for histopathological findings of post-transplantation neoplasm in this pediatric patient population. RESULTS: The study population consisted of 14 consecutive pediatric patients (7 boys and 7 girls; mean age 26 months, range 4-113 months). Of these 14 children, 4 (29%) developed histologically confirmed post-transplant neoplasms at a mean time of 2.4 years after multivisceral transplantation. Types of neoplasms included post-transplant lymphoproliferative disorder (PTLD) in three (21%) and Epstein-Barr-virus-associated smooth muscle tumor in two (14%). (One child developed both neoplasms following transplantation). Both children with smooth muscle tumor associated with Epstein-Barr virus presented with characteristic hypointense solid masses with peripheral rim enhancement on cross-sectional imaging studies. The mortality rate of children who developed post-transplant neoplasms was higher than that of those who did not develop post-transplant neoplasm (50% vs. 10%, P = 0.17), suggesting a possible risk factor for death. CONCLUSION: Post-transplant neoplasm in children with multivisceral transplantation occurs with high frequency, often presents as Epstein-Barr-virus-associated smooth muscle tumor showing characteristic peripheral rim enhancement on cross-sectional imaging studies.