Survival after relapse in childhood acute lymphoblastic leukemia: impact of site and time to first relapse--the Children's Cancer Group Experience

Isolated lacrimal gland enlargement as a presenting sign of relapse of B-cell acute lymphoblastic leukemia in an adult

A 25-year-old woman with a history of acute lymphoblastic leukemia with Philadelphia chromosome (BCR 22q11.2-ABL1 (9q34)) presented with progressively worsening swelling and pain in her left upper eyelid of 3 months' duration. Magnetic resonance imaging showed a heterogeneously enhancing mass lesion in the left lacrimal gland. An incisional biopsy was performed; histopathology showed atypical lymphocytic cells, and flow cytometry revealed a similar immunophenotype to her previously diagnosed cancer. Her presentation was consistent with recurrence of acute lymphoblastic leukemia in the lacrimal gland, which can rarely be involved in relapse of acute lymphoblastic leukemia.

Three-year results from phase I of ZUMA-4: KTE-X19 in pediatric relapsed/refractory acute lymphoblastic leukemia

Here we present the 3-year results of ZUMA-4, a phase I/II multicenter study evaluating the safety and efficacy of KTEX19, an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, in pediatric/adolescent patients with relapsed/refractory B-cell acute lymphoblastic leukemia. Phase I explored two dose levels and formulations. The primary endpoint was the incidence of dose-limiting toxicities. Thirty-one patients were enrolled; KTE-X19 was administered to 24 patients (median age 13.5 years, range 3-20; median follow-up 36.1 months). No dose-limiting toxicities were observed. All treated patients had grade ≥3 adverse events, commonly hypotension (50%) and anemia (42%). Grade 3 cytokine release syndrome rates were 33% in all treated patients, 75% in patients given the dose of 2×106 CAR T cells/kg, 27% in patients given the dose of 1×106 cells/kg in the 68 mL formulation, and 22% in patients given the dose of 1×106 cells/kg in the 40 mL formulation; the percentages of patients experiencing grade ≥3 neurologic events were 21%, 25%, 27%, and 11% respectively. Overall complete remission rates (including complete remission with incomplete hematologic recovery) were 67% in all treated patients, 75% in patients given 2×106 CAR T cells/kg, 64% in patients given 1×106 cells/kg in the 68 mL formulation, and 67% in patients given 1×106 cells/kg in the 40 mL formulation. Overall minimal residual diseasenegativity rates were 100% among responders; 88% of responders underwent subsequent allogeneic stem-cell transplantation. In the 1×106 (40 mL) group (recommended phase II dose), the median duration of remission censored at allogeneic stem-cell transplantation and median overall survival were not reached. Pediatric/adolescent patients with relapsed/refractory B-cell acute lymphoblastic leukemia achieved high minimal residual disease-negative remission rates with a manageable safety profile after a single dose of KTE-X19. Phase II of the study is ongoing at the dose of 1×106 CAR T cells/kg in the 40 mL formulation. ClinicalTrials.gov: NCT02625480.

Measuring disparities in event-free survival among children with acute lymphoblastic leukemia in an academic institute in Oklahoma, 2005-2019

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common type of childhood cancer. While there have been successes in the treatment of leukemia, less information is available on reasons for disparities in event-free survival (EFS) among underserved populations.

METHODS

We partnered with a children's hospital at an academic institution to abstract data from the institution's cancer registry, the state cancer registry, and electronic medical records on cancer diagnosis, treatment, and outcomes for children with ALL (n = 275) diagnosed from 2005 to 2019 prior to age 20. We evaluated the relation between 1) race/ethnicity, 2) distance to the children's hospital, and 3) area deprivation with EFS, defined as time from diagnosis to relapse, death, or the end of the study period. We evaluated differences in EFS using Kaplan-Meier analysis with the log-rank test. We used the Cox Proportional Hazards Model for multivariable survival analyses.

RESULTS

Most children were diagnosed with ALL under five years of age (45%) and with Pre-B ALL (87%). Twelve percent of children experienced a relapse and 5% died during induction or remission. EFS at 5 years was 82%. Non-Hispanic (NH) Black children had worse, though imprecise, EFS compared to NH White children (Adjusted Hazard Ratio: 2.07, 95% CI: 0.80, 5.38). Children residing in areas with higher deprivation had a higher adjusted hazard of poor outcomes compared to the least deprived areas, though estimates were imprecise (2nd quartile HR: 1.51, 3rd quartile: 1.85, 4th quartile: 1.62). We observed no association between distance to the children's hospital and EFS.

CONCLUSION

We observed poorer EFS for NH Black children and children residing in areas with high deprivation, though the estimates were not statistically significant. Our next steps include further evaluating socioeconomic factors in both rural and urban children to identify disparities in outcomes for children with ALL and other childhood cancers.

Relapses Children's Acute Lymphoblastic Leukemia, Single Center Experience

The prognosis in children and adolescents with relapsed ALL, despite intensive therapy, including hematopoietic stem cell transplantation, is still challenging. This study aims to analyze the incidence of relapsed ALL and survival rates in correlation to the risk factors. Materials and methods: 125 pediatric patients with ALL diagnosed in our department between 2000-2018; age 1−18 years old (median 6.4); female 53.6% vs. male 46.4%. Results: 19 pts (15.2%) were diagnosed with a relapse. Three pts (15.8%) had been diagnosed with very early relapses (2/3 T-ALL), 12 pts (63.1%) as an early relapse, and 4 pts (21.1%) as a late relapse. Bone marrow was the most frequent relapses localization. The five-year survival has been achieved by six patients (31.6%). A significant difference was found in regard to the five-year overall survival and relapse type (p < 0.05). The group with very early relapses (3/3; 100%) has not reached the five-year survival. Conclusions: 1. The main prognostic factor in children’s ALL relapses is still the time of the onset of the relapse. 2. The T lineage acute lymphoblastic leukemia is a worse prognostic factor. 3. The analysis of the above relapse risk factors alongside cytogenethic markers and flow cytometry or polymerase chain reaction minimal residual disease is very important for first-line chemotherapy improvement and a more personalized choice of therapy for ALL patients.

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

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

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

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

Allogeneic Hematopoietic Stem Cell Transplantation for Children With Acute Lymphoblastic Leukemia: Shifting Indications in the Era of Immunotherapy

Pediatric acute lymphoblastic leukemia generally carries a good prognosis, and most children will be cured and become long-term survivors. However, a portion of children will harbor high-risk features at the time of diagnosis, have a poor response to upfront therapy, or suffer relapse necessitating more intensive therapy, which may include allogeneic hematopoietic stem cell transplant (HSCT). Recent advances in risk stratification, improved detection and incorporation of minimal residual disease (MRD), and intensification of upfront treatment have changed the indications for HSCT over time. For children in first complete remission, HSCT is generally reserved for those with the highest risk of relapse. These include patients with unfavorable features/cytogenetics who also have a poor response to induction and consolidation chemotherapy, usually reflected by residual blasts after prednisone or by detectable MRD at pre-defined time points. In the relapsed setting, children with first relapse of B-cell ALL are further stratified for HSCT depending on the time and site of relapse, while all patients with T-cell ALL are generally consolidated with HSCT. Alternatives to HSCT have also emerged over the last decade including immunotherapy and chimeric antigen receptor (CAR) T-cell therapy. These novel agents may spare toxicity while attempting to achieve MRD-negative remission in the most refractory cases and serve as a bridge to HSCT. In some situations, these emerging therapies can indeed be curative for some children with relapsed or resistant disease, thus, obviating the need for HSCT. In this review, we seek to summarize the role of HSCT in the current era of immunotherapy.

Other (Non-CNS/Testicular) Extramedullary Localizations of Childhood Relapsed Acute Lymphoblastic Leukemia and Lymphoblastic Lymphoma-A Report from the ALL-REZ Study Group

Children with other extramedullary relapse of acute lymphoblastic leukemia are currently poorly characterized. We aim to assess the prevalence and the clinical, therapeutic and prognostic features of extramedullary localizations other than central nervous system or testis in children with relapse of acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LBL) treated on a relapsed ALL protocol.

PATIENTS AND METHODS

Patients with relapse of ALL and LBL, treated according to the multicentric ALL-REZ BFM trials between 1983 and 2015, were analyzed for other extramedullary relapse (OEMR) of the disease regarding clinical features, treatment and outcome. Local treatment/irradiation has been recommended on an individual basis and performed only in a minority of patients.

RESULTS

A total of 132 out of 2323 (5.6%) patients with ALL relapse presented with an OEMR (combined bone marrow relapse n = 78; isolated extramedullary relapse n = 54). Compared to the non-OEMR group, patients with OEMR had a higher rate of T-immunophenotype (p < 0.001), a higher rate of LBL (p < 0.001) and a significantly different distribution of time to relapse, i.e., more very early and late relapses compared to the non-OEMR group (p = 0.01). Ten-year probabilities of event-free survival (pEFS) and overall survival (pOS) in non-OEMR vs. OEMR were 0.38 ± 0.01 and 0.32 ± 0.04 (p = 0.0204) vs. 0.45 ± 0.01 and 0.37 ± 0.04 (p = 0.0112), respectively. OEMRs have been classified into five subgroups according to the main affected compartment: lymphatic organs (n = 32, 10y-pEFS 0.50 ± 0.09), mediastinum (n = 35, 10y-pEFS 0.11 ± 0.05), bone (n = 12, 0.17 ± 0.11), skin and glands (n = 21, 0.32 ± 0.11) and other localizations (n = 32, 0.41 ± 0.09). Patients with OEMR and T-lineage ALL/LBL showed a significantly worse 10y-pEFS (0.15 ± 0.04) than those with B-Precursor-ALL (0.49 ± 0.06, p < 0.001). Stratified into standard risk (SR) and high risk (HR) groups, pEFS and pOS of OEMR subgroups were in the expected range whereas the mediastinal subgroup had a significantly worse outcome. Subsequent relapses involved more frequently the bone marrow (58.4%) than isolated extramedullary compartments (41.7%). In multivariate Cox regression, OEMR confers an independent prognostic factor for inferior pEFS and pOS.

CONCLUSION

OEMR is adversely related to prognosis. However, the established risk classification can be applied for all subgroups except mediastinal relapses requiring treatment intensification. Generally, isolated OEMR of T-cell-origin needs an intensified treatment including allogeneic stem cell transplantation (HSCT) as a curative approach independent from time to relapse. Local therapy such as surgery and irradiation may be of benefit in selected cases. The indication needs to be clarified in further investigations.

The role of scrotal ultrasonography from infancy to puberty

Background

Scrotal ultrasonography is an essential diagnostic tool in daily clinical practice. The availability of new‐generation ultrasound machines characterized by clearly improved image quality, low health cost, and higher patient safety, represents only some characteristics of ultrasound investigation. The usefulness of scrotal ultrasonography is particularly evident in the period of life from infancy to puberty, during which males undergo important morphofunctional changes, and several pathological conditions may occur.

Objectives

This pictorial review primarily aimed to investigate the aspects of ultrasonography related to the normal physiological development of the gonads from mini‐puberty to pubertal onset. This study also aimed to provide an update on the use of ultrasonography in main andrological pathologies that may occur during this period. The conditions that are discussed in depth are: cryptorchidism, inguinoscrotal hernias, and hydrocele in the neonatal phase; acute scrotum, epididymo‐orchitis, and testicular cancers in childhood; and hypogonadism, varicoceles, testicular microlithiasis, and oncohematological pathology in puberty.

Discussion

We provided an ultrasound slant for all the above‐mentioned pathologies while purposely avoiding excessive deepening of the pathogenetic, clinical, and therapeutic aspects. Studying the ultrasound aspects of the gonads also facilitates differential diagnosis between various conditions and represents a good aid in evaluating therapeutic success (e.g., in hypogonadism or postsurgical evaluation of varicoceles and cryptorchidism).

Conclusion

Scrotal ultrasonography is now globally recognized as the necessary completion of clinical–laboratory overview in gonads evaluation. This diagnostic procedure is even more indispensable in the infancy–childhood–puberty period for the evaluation of normal gonadal development as well as diagnosis of other possible diseases.

Integrin α6 mediates the drug resistance of acute lymphoblastic B-cell leukemia

Resistance to multimodal chemotherapy continues to limit the prognosis of acute lymphoblastic leukemia (ALL). This occurs in part through a process called adhesion-mediated drug resistance, which depends on ALL cell adhesion to the stroma through adhesion molecules, including integrins. Integrin α6 has been implicated in minimal residual disease in ALL and in the migration of ALL cells to the central nervous system. However, it has not been evaluated in the context of chemotherapeutic resistance. Here, we show that the anti-human α6-blocking Ab P5G10 induces apoptosis in primary ALL cells in vitro and sensitizes primary ALL cells to chemotherapy or tyrosine kinase inhibition in vitro and in vivo. We further analyzed the underlying mechanism of α6-associated apoptosis using a conditional knockout model of α6 in murine BCR-ABL1+ B-cell ALL cells and showed that α6-deficient ALL cells underwent apoptosis. In vivo deletion of α6 in combination with tyrosine kinase inhibitor (TKI) treatment was more effective in eradicating ALL than treatment with a TKI (nilotinib) alone. Proteomic analysis revealed that α6 deletion in murine ALL was associated with changes in Src signaling, including the upregulation of phosphorylated Lyn (pTyr507) and Fyn (pTyr530). Thus, our data support α6 as a novel therapeutic target for ALL.

Prognostic Value and Outcome for ETV6/RUNX1-Positive Pediatric Acute Lymphoblastic Leukemia: A Report From the South China Children's Leukemia Group

PURPOSE

To analyzed the outcome of ETV6/RUNX1-positive pediatric acute B lymphoblastic leukemia (B-ALL) with the aim of identifying prognostic value.

METHOD

A total of 2,530 pediatric patients who were diagnosed with B-ALL were classified into two groups based on the ETV6/RUNX1 status by using a retrospective cohort study method from February 28, 2008, to June 30, 2020, at 22 participating ALL centers.

RESULTS

In total, 461 (18.2%) cases were ETV6/RUNX1-positive. The proportion of patients with risk factors (age <1 year or ≥10 years, WB≥50×10⁹/L) in ETV6/RUNX1-positive group was significantly lower than that in negative group (P<0.001), while the proportion of patients with good early response (good response to prednisone, D15 MRD < 0.1%, and D33 MRD < 0.01%) in ETV6/RUNX1-positive group was higher than that in the negative group (P<0.001, 0.788 and 0.004, respectively). Multivariate analysis of 2,530 patients found that age <1 or ≥10 years, SCCLG-ALL-2016 protocol, and MLL were independent predictor of outcome but not ETV6/RUNX1. The EFS and OS of the ETV6/RUNX1-positive group were significantly higher than those of the negative group (3-year EFS: 90.11 ± 4.21% vs 82 ± 2.36%, P<0.0001, 3-year OS: 91.99 ± 3.92% vs 88.79 ± 1.87%, P=0.017). Subgroup analysis showed that chemotherapy protocol, age, prednisone response, and D15 MRD were important factors affecting the prognosis of ETV6/RUNX1-positive children.

CONCLUSIONS

ETV6/RUNX1-positive pediatric ALL showed an excellent outcome but lack of independent prognostic significance in South China. However, for older patients who have the ETV6/RUNX1 fusion and slow response to therapy, to opt for more intensive treatment.

Cadherins, Selectins, and Integrins in CAM-DR in Leukemia

The interaction between leukemia cells and the bone microenvironment is known to provide drug resistance in leukemia cells. This phenomenon, called cell adhesion-mediated drug resistance (CAM-DR), has been demonstrated in many subsets of leukemia including B- and T-acute lymphoblastic leukemia (B- and T-ALL) and acute myeloid leukemia (AML). Cell adhesion molecules (CAMs) are surface molecules that allow cell-cell or cell-extracellular matrix (ECM) adhesion. CAMs not only recognize ligands for binding but also initiate the intracellular signaling pathways that are associated with cell proliferation, survival, and drug resistance upon binding to their ligands. Cadherins, selectins, and integrins are well-known cell adhesion molecules that allow binding to neighboring cells, ECM proteins, and soluble factors. The expression of cadherin, selectin, and integrin correlates with the increased drug resistance of leukemia cells. This paper will review the role of cadherins, selectins, and integrins in CAM-DR and the results of clinical trials targeting these molecules.

Meta-Analysis of Anxiety in Parents of Young People with Chronic Health Conditions

OBJECTIVE

Chronic health conditions are often associated with uncertainty and threats which may cause anxiety in the family members. The present meta-analysis analyzed whether parents of children with chronic physical diseases and/or sensory/physical disabilities show higher anxiety levels than parents of healthy/nondisabled children or test norms.

METHODS

The databases PSYCINFO, MEDLINE, Google Scholar, CINAHL, and PSYNDEX were searched for relevant studies. In total, 486 studies were identified that fulfilled the inclusion criteria.

RESULTS

We found moderate elevations of anxiety symptoms in parents of young people with chronic conditions (g = .54 standard deviation units). About 16% of the parents fulfilled the criteria for an anxiety disorder. Parents of young people with neuromuscular disorders, HIV-infection/AIDS, and cancer during active treatment showed large elevations of anxiety symptoms. Elevations of anxiety symptoms were smaller in the cases of longer lasting chronic conditions, longer time since the end of active treatment, in families of older children, in samples with lower percentages of mothers, and in studies from economically developed countries compared to less developed countries.

CONCLUSION

Measures for preventing and reducing anxiety symptoms in parents of young people with neuromuscular disorders, HIV-infection/AIDS, and those undergoing cancer treatments are particularly needed.

Integrin-Mediated Adhesion and Chemoresistance of Acute Lymphoblastic Leukemia Cells Residing in the Bone Marrow or the Central Nervous System

Acute Lymphoblastic Leukemia (ALL) is the most common cancer in childhood. Despite a significantly improved prognosis over the last decade with a 5-years survival rate of ~90%, treatment-related morbidity remains substantial and relapse occurs in 10–15% of patients (1). The most common site of relapse is the bone marrow, but early colonization and subsequent reoccurrence of the disease in the central nervous system (CNS) also occurs. Integrins are a family of cell surface molecules with a longstanding history in cancer cell adherence, migration and metastasis. In chronic lymphoblastic leukemia (CLL), the VLA-4 integrin has been acknowledged as a prognostic marker and mounting evidence indicates that this and other integrins may also play a role in acute leukemia, including ALL. Importantly, integrins engage in anti-apoptotic signaling when binding extracellular molecules that are enriched in the bone marrow and CNS microenvironments. Here, we review the current evidence for a role of integrins in the adherence of ALL cells within the bone marrow and their colonization of the CNS, with particular emphasis on mechanisms adding to cancer cell survival and chemoresistance.

Improving Stratification for Children With Late Bone Marrow B-Cell Acute Lymphoblastic Leukemia Relapses With Refined Response Classification and Integration of Genetics

PURPOSE

Minimal residual disease (MRD) helps to accurately assess when children with late bone marrow relapses of B-cell precursor (BCP) acute lymphoblastic leukemia (ALL) will benefit from allogeneic hematopoietic stem-cell transplantation (allo-HSCT). More detailed dissection of MRD response heterogeneity and the specific genetic aberrations could improve current practice.

PATIENTS AND METHODS

MRD was assessed after induction treatment and at different times during relapse treatment until allo-HSCT (indicated in poor responders to induction; MRD ≥ 10−3) for patients being treated for late BCP-ALL bone marrow relapses (n = 413; median follow-up, 9.4 years) in the ALL-REZ BFM 2002 trial/registry (ClinicalTrials.gov identifier: NCT00114348 ).

RESULTS

Patients with both good (MRD < 10−3) and poor responses to induction treatment reached excellent event-free survival (EFS; 72% v 65%) and overall survival (OS; 82% v 74%). Patients with MRD of 10−2 or greater after induction had reduced EFS (56%), and their MRD persisted until allo-HSCT more frequently than it did in patients with MRD of 10−3 or greater to less than 10−2 ( P = .037). Patients with 25% or more leukemic blasts after induction (early nonresponders) had the poorest prognosis (EFS, 22%). Interestingly, patients with MRD of 10−3 or greater before allo-HSCT (late nonresponders) still had an EFS of 50% and OS of 63%, which in principle justifies allo-HSCT in these patients. From a panel of selected candidate genes, TP53 alterations (frequency, 8%) were the only genetic alteration with independent prognostic value in any MRD-based response subgroup.

CONCLUSION

After induction treatment, MRD-based treatment stratification resulted in excellent survival in patients with late relapsed BCP-ALL. Prognosis could be further improved in very poor responders by intensifying treatment directly after induction. TP53 alterations can be defined as a novel genetic high-risk marker in all MRD response groups in late relapsed BCP-ALL. Here we identified early and late nonresponders to be considered as events in future trials.

Cancer Stem Cells in the Development of Novel Therapeutics for Refractory Pediatric Leukemia

Although treatment strategies for pediatric leukemia have improved overall survival rates in the recent past, relapse rates in certain subgroups such as infant leukemia remain unacceptably high. Despite undergoing extensive chemotherapy designed to target the rapidly proliferating leukemia cells, many of these children experience relapse. In refractory leukemia, the existence of cell populations with stemness characteristics, termed leukemia stem cells (LSCs), which remain quiescent and subsequently replenish the blast population, has been described. A significant body of evidence exists, derived largely from xenograft models of adult acute myeloid leukemia, to support the idea that LSCs may play a fundamental role in refractory disease. In addition, clinical studies have also linked LSCs with increased minimal residual disease, higher relapse rate, and decreased survival rates in these patients. Recently, a number of reports have addressed effective ways to utilize new-generation genomic sequencing and transcriptomic analyses to identify targeted therapeutic agents aimed at LSCs, while sparing normal hematopoietic stem cells. These data underscore the value of timely translation of knowledge from adult studies to the unique molecular and physiological characteristics seen in pediatric leukemia. We aim to summarize this article in the rapidly expanding field of stem cell biology in hematopoietic malignancies, focusing particularly on relevant preclinical models and novel targeted therapeutics, and their applicability to childhood leukemia.

Severe Epididymo-Orchitis and Encephalitis Complicating Anti-PD-1 Therapy

BACKGROUND

Immune checkpoint inhibitors such as pembrolizumab and nivolumab have emerged as active treatment options for patients with many cancers, including metastatic melanoma, but can also cause symptomatic or life-threatening immune-related adverse events, including encephalitis. Epididymitis and orchitis are rare complications of these therapies.

CASE PRESENTATION

We describe herein a patient with metastatic melanoma who developed epididymo-orchitis followed by encephalitis while receiving pembrolizumab. The patient developed testicular pain and fever after his third dose of pembrolizumab; ultrasound evaluation demonstrated bilateral epididymo-orchitis. He then developed headaches, fever, and altered mental status over the next week and was admitted to the hospital. Lumbar puncture revealed inflammatory changes consistent with meningoencephalitis; he did not improve with broad-spectrum antibiotics, and an extensive workup for infectious etiologies, including cerebrospinal fluid testing using a clinical metagenomic next-generation sequencing assay, was negative. He received high-dose steroids for suspected autoimmune encephalitis, and both his orchitis and meningoencephalitis improved rapidly after one dose. He fully recovered after a 5-week taper of oral steroids.

DISCUSSION

Here, we report a case of epididymo-orchitis complicating immune checkpoint inhibitor therapy. This patient subsequently developed severe encephalitis but rapidly improved with steroids. Clinicians should be aware of rare complications of these agents.

KEY POINTS

Epididymo-orchitis is a rare and potentially life-threatening complication of anti-programmed death protein 1 (anti-PD-1) therapy.For patients on anti-PD-1 therapy who develop either epididymo-orchitis or epididymitis without clear infectious cause, immune-related adverse events should be considered in the differential diagnosis.If severe, epididymo-orchitis related to anti-PD-1 therapy may be treated with high-dose corticosteroids.

Prognostic gene alterations and clonal changes in childhood B-ALL

Genomic profiles of leukemia patients lead to characterization of variations that provide the molecular classification of risk groups, prediction of clinical outcome and therapeutic decisions. In this study, we examined the diagnostic (n = 77) and relapsed (n = 31) pediatric B-cell acute lymphoblastic leukemia (B-ALL) samples for the most common leukemia-associated gene variations CRLF2, JAK2, PAX5 and IL7R using deep sequencing and copy number alterations (CNAs) (CDKN2A/2B, PAX5, RB1, BTG1, ETV6, CSF2RA, IL3RA and CRLF2) by multiplex ligation proximity assay (MLPA), and evaluated for the clonal changes through relapse. Single nucleotide variations SNVs were detected in 19% of diagnostic 15.3% of relapse samples. The CNAs were detected in 55% of diagnosed patients; most common affected genes were CDKN2A/2B, PAX5, and CRLF2. Relapse samples did not accumulate a greater number of CNAs or SNVs than the cohort of diagnostic samples, but the clonal dynamics showed the accumulation/disappearance of specific gene variations explained the course of relapse. The CDKN2A/2B were most frequently altered in relapse samples and 32% of relapse samples carried at least one CNA. Moreover, CDKN2A/2B alterations and/or JAK2 variations were associated with decreased relapse-free survival. On the other hand, CRLF2 copy number alterations predicted a better survival rate in B-ALL. These findings contribute to the knowledge of CDKN2A/2B and CRLF2 alterations and their prognostic value in B-ALL. The integration of genomic data in clinical practice will enable better stratification of ALL patients and allow deeper understanding of the nature of relapse.

Treatment of higher risk acute lymphoblastic leukemia in young people (CCG-1961), long-term follow-up: a report from the Children's Oncology Group

Children's Cancer Group CCG-1882 improved outcome for 1-21-year old with high risk acute lymphoblastic leukemia and Induction Day 8 marrow blasts ≥25% (slow early responders, SER) with longer and stronger post induction intensification (PII). This CCG-1961 explored alternative PII strategies. We report 10-year follow-up for patients with rapid early response (RER) and for the first time details our experience for SER patients. A total of 2057 patients were enrolled, and 1299 RER patients were randomized to 1 of 4 PII regimens: standard vs. augmented intensity and standard vs. increased length. At the end of interim maintenance, 447 SER patients were randomized to idarubicin/cyclophosphamide or weekly doxorubicin in the delayed intensification phases. The 10-year EFS for RER were 79.4 ± 2.4% and 70.9 ± 2.6% (hazard ratio = 0.65, 95% CI 0.52-0.82, p < 0.001) for augmented and standard strength PII; the 10-year OS rates were 87.2 ± 2.0% and 81.0 ± 2.2% (hazard ratio = 0.64, 95% CI 0.48-0.86, p = 0.003). Outcomes remain similar for standard and longer PII, and for SER patients assigned to idarubicin/cyclophosphamide and weekly doxorubicin. The EFS and OS advantage of augmented PII is sustained at 10 years for RER patients. Longer PII for RER patients and sequential idarubicin/cyclophosphamide for SER patients offered no advantage. CCG-1961 is the platform for subsequent COG studies.

Targeting PI3K Signaling in Acute Lymphoblastic Leukemia

Adhesion of acute lymphoblastic leukemia (ALL) cells to bone marrow stroma cells triggers intracellular signals regulating cell-adhesion-mediated drug resistance (CAM-DR). Stromal cell protection of ALL cells has been shown to require active AKT. In chronic lymphocytic leukemia (CLL), adhesion-mediated activation of the PI3K/AKT pathway is reported. A novel FDA-approved PI3Kδ inhibitor, CAL-101/idelalisib, leads to downregulation of p-AKT and increased apoptosis of CLL cells. Recently, two additional PI3K inhibitors have received FDA approval. As the PI3K/AKT pathway is also implicated in adhesion-mediated survival of ALL cells, PI3K inhibitors have been evaluated preclinically in ALL. However, PI3K inhibition has yet to be approved for clinical use in ALL. Here, we review the role of PI3K in normal hematopoietic cells, and in ALL. We focus on summarizing targeting strategies of PI3K in ALL.

[Use of blinatumomab in children acute lymphoblastic leukemia in the Grand Ouest interregion: A chance for all]

INTRODUCTION

Relapsed/refractory acute lymphoblastic leukemia (ALL) in children has a pejorative prognosis and justifies to be treated by hematopoietic stem cell transplantation (HSCT). A minimal residual disease (MRD) before transplantation is a major part of prognosis. Blinatumomab, a bispecific antibody CD19⁺/CD3⁺, allowed to achieve a cytologic and molecular complete remission in adults with refractory B-precursor ALL. This retrospective study analyses results from a pediatric cohort treated by blinatumomab thanks to an interregional structuring consortium.

PATIENTS AND METHODS

Patients between 0 and 23 years old, from the 7 centers of the french "Grand Ouest" interregional network, treated by blinatumomab for a relapsed or refractory ALL, from January 2015 to January 2018, were included. The efficiency of blinatumomab was assessed in terms of complete remission, minimal residual disease, overall survival, and tolerability of treatment.

RESULTS

Thirteen of 18 patients achieved a complete remission, with negative minimal residual disease for ten of them. Fourteen patients proceeded to stem cell transplantation,. Eight out of 14 patients obtained long term remission after HSCT. As far as tolerance is concerned, no serious adverse event, neurological or psychiatric disorder, was observed.

CONCLUSION

Thanks to an interregional network collaboration, all children with high risk ALL coming from the western french interregion could be treated by blinatumomab. Blinatumomab offered good hematological conditions to undergo HSCT with a good tolerability.

Panel-based next-generation sequencing identifies prognostic and actionable genes in childhood acute lymphoblastic leukemia and is suitable for clinical sequencing

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. Although the cure rate of ALL has greatly improved, a considerable number of patients suffer from relapse of leukemia. Therefore, ALL remains the leading cause of death from cancer during childhood. To improve the cure rate of these patients, precisely detecting patients with high risk of relapse and incorporating new targeted therapies are urgently needed. This study investigated inexpensive, rapid, next-generation sequencing of more than 150 cancer-related genes for matched diagnostic, remission, and relapse samples of 17 patients (3 months to 15 years old) with relapsed ALL. In this analysis, we identified 16 single-nucleotide variants (SNVs) and insertion/deletion variants and 19 copy number variants (CNVs) at diagnosis and 28 SNVs and insertion/deletion variants and 22 CNVs at relapse. With these genetic alterations, we could detect several B cell precursor ALL patients with high-risk gene alterations who were not stratified into the highest-risk group (5/8, 62.5%). We also detected potentially actionable genetic variants in about half of the patients (8/17, 47.1%). Among them, we found that one patient harbored germline TP53 mutation as a secondary finding. This inexpensive, rapid method can be immediately applied as clinical sequencing and could lead to better management of these patients and potential improvement in the survival rate in childhood ALL.

Nucleotide excision repair is a predictor of early relapse in pediatric acute lymphoblastic leukemia

BACKGROUND

Nucleotide Excision Repair (NER) is a major pathway of mammalian DNA repair that is associated with drug resistance and has not been well characterized in acute lymphoblastic leukemia (ALL). The objective of this study was to explore the role of NER in relapsed ALL patients. We hypothesized that increased expression of NER genes was associated with drug resistance and relapse in ALL.

METHODS

We performed secondary data analysis on two sets of pediatric ALL patients that all ultimately relapsed, and who had matched diagnosis-relapse gene expression microarray data (GSE28460 and GSE18497). GSE28460 included 49 precursor-B-ALL patients, and GSE18497 included 27 precursor-B-ALL and 14 T-ALL patients. Microarray data were processed using the Plier 16 algorithm and the 20 canonical NER genes were extracted. Comparisons were made between time of diagnosis and relapse, and between early and late relapsing subgroups. The Chi-square test was used to evaluate whether NER gene expression was altered at the level of the entire pathway and individual gene expression was compared using t-tests.

RESULTS

We found that gene expression of the NER pathway was significantly increased upon relapse in patients that took 3 years or greater to relapse (late relapsers, P = .007), whereas no such change was evident in patients that relapsed in less than 3 years (early relapsers, P = .180). Moreover, at diagnosis, the NER gene expression of the early relapsing subpopulation was already significantly elevated over that of the late relapsing group (P < .001). This pattern was validated by an 'NER score' established by averaging the relative expression of the 20 canonical NER genes. The NER score at diagnosis was found to be significantly associated with disease-free survival in precursor-B-ALL (P < .001).

CONCLUSION

Patients are over two times more likely to undergo early relapse if they have a high NER score at diagnosis, hazard ratio 2.008, 95% CI (1.256-3.211). The NER score may provide a underlying mechanism for "time to remission", a known prognostic factor in ALL, and a rationale for differential treatment.

Survival after stem-cell transplant in pediatric and young-adult patients with relapsed and refractory B-cell acute lymphoblastic leukemia

OBJECTIVE

Allogeneic stem-cell transplant (allo-SCT) is the standard of care for pediatric patients with acute lymphoblastic leukemia (ALL) who relapse after frontline chemotherapy; however, for patients who relapse after allo-SCT, outcomes are very poor. Few studies have examined overall survival in this patient population, particularly in patients who received a second allo-SCT.

METHODS

This was a retrospective analysis using data from the Center for International Blood and Marrow Transplant Research (CIBMTR) registry. The study population included patients aged 3 to 21 years who were diagnosed with B-ALL and underwent their first allo-SCT between 2009 and 2013. The primary endpoint was the time from the date of posttransplant relapse to the date of death due to any reason.

RESULTS

Outcomes in 1349 pediatric and young-adult patients were included in this analysis. The Kaplan-Meier estimated probability of survival at 3 years after first allo-SCT was 63.1% (95% CI, 60.2%-65.8%). Overall, 29.2% of patients relapsed after first allo-SCT and had a median survival of 7.4 months (95% CI, 6.0-9.6 months). Twenty-five patients in the analysis developed secondary malignancies, most of which were lymphoproliferative disorders.

CONCLUSIONS

Survival rates are low in pediatric and young-adult patients who relapse after first and second allo-SCT, and new therapies are needed to improve outcomes in this population. This data can be used as a historical comparison for single-arm trials of novel therapies for this patient population, including chimeric antigen receptor T-cell therapy.

Relapse of childhood acute lymphoblastic leukemia and outcomes at a reference center in Latin America: organomegaly at diagnosis is a significant clinical predictor

OBJECTIVE

Relapse is the major cause of treatment failure in acute lymphoblastic leukemia (ALL) of childhood; it is more frequent among high-risk patients from low-middle income than from high-income countries. The frequency, sites and outcome of relapsed ALL in children of northeast Mexico over a decade was documented.

METHODS

A retrospective analysis of 246 children belonging to a low-income group <16 years with de novo ALL during 2004-2015 was performed. Five-year overall survival (OS) and event-free survival was estimated by Kaplan-Meier analysis. Data on time, site, response to therapy and final outcome of relapse were analyzed. Hazard ratios (HRs) of relapse and death were estimated by the Cox regression model. Very early relapse was defined as that occurring in <18 months, early relapse between 18 and 36 months, and late relapse >36 months from diagnosis, respectively.

RESULTS

Eighty-seven (35.4%) children relapsed. Five-year OS was 82.6% in children without relapse vs. 42% for relapsed patients. Bone marrow (BM) was the most frequent site of relapse (51.72%). Isolated central nervous system (CNS) relapses occurred in 29.9%. Five-year OS was 11.2% for BM and 15.5% for early relapse. HR of relapse for organomegaly was 3.683, 2.247 for an initial white blood cell count >50 000 × 10⁹/l and 1.169 for positive minimal residual disease status.

CONCLUSION

A high rate of very early, CNS, and BM relapse with a considerably low 5-year OS requiring reassessment of therapy was documented. Organomegaly at diagnosis was a highly significant clinical predictor for relapse.

Outcome of Reinduction Chemotherapy with a Modified Dose of Idarubicin for Children with Marrow-Relapsed Acute Lymphoblastic Leukemia: Results of the Childhood Acute Lymphoblastic Leukemia (CALL)-0603 Study

This multicenter, prospective trial was conducted to develop an effective and safe reinduction regimen for marrow-relapsed pediatric acute lymphoblastic leukemia (ALL) by modifying the dose of idarubicin. Between 2006 and 2009, the trial accrued 44 patients, 1 to 21 years old with first marrow-relapsed ALL. The reinduction regimen comprised prednisolone, vincristine, L-asparaginase, and idarubicin (10 mg/m²/week). The idarubicin dose was adjusted according to the degree of myelosuppression. The second complete remission (CR2) rate was 72.7%, obtained by 54.2% of patients with early relapse < 24 months after initial diagnosis and 95.0% of those with late relapse (P = 0.002). Five patients entered remission with extended treatment, resulting in a final CR2 rate of 84.1%. The CR2 rate was not significantly different according to the idarubicin dose. The induction death rate was 2.3% (1/44). The 5-year event-free and overall survival rates were 22.2% ± 6.4% and 27.3% ± 6.7% for all patients, 4.2% ± 4.1% and 8.3% ± 5.6% for early relapsers, and 43.8% ± 11.4% and 50.0% ± 11.2% for late relapsers, respectively. Early relapse and slow response to reinduction chemotherapy were predictors of poor outcomes. In conclusion, a modified dose of idarubicin was effectively incorporated into the reinduction regimen for late marrow-relapsed ALL with a low toxic death rate. However, the CR2 rate for early relapsers was suboptimal, and the second remission was not durable in most patients.

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

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

Synergistic cytotoxic effects of bortezomib and CK2 inhibitor CX-4945 in acute lymphoblastic leukemia: turning off the prosurvival ER chaperone BIP/Grp78 and turning on the pro-apoptotic NF-κB

The proteasome inhibitor bortezomib is a new targeted treatment option for refractory or relapsed acute lymphoblastic leukemia (ALL) patients. However, a limited efficacy of bortezomib alone has been reported. A terminal pro-apoptotic endoplasmic reticulum (ER) stress/unfolded protein response (UPR) is one of the several mechanisms of bortezomib-induced apoptosis. Recently, it has been documented that UPR disruption could be considered a selective anti-leukemia therapy. CX-4945, a potent casein kinase (CK) 2 inhibitor, has been found to induce apoptotic cell death in T-ALL preclinical models, via perturbation of ER/UPR pathway. In this study, we analyzed in T- and B-ALL preclinical settings, the molecular mechanisms of synergistic apoptotic effects observed after bortezomib/CX-4945 combined treatment. We demonstrated that, adding CX-4945 after bortezomib treatment, prevented leukemic cells from engaging a functional UPR in order to buffer the bortezomib-mediated proteotoxic stress in ER lumen. We documented that the combined treatment decreased pro-survival ER chaperon BIP/Grp78 expression, via reduction of chaperoning activity of Hsp90. Bortezomib/CX-4945 treatment inhibited NF-κB signaling in T-ALL cell lines and primary cells from T-ALL patients, but, intriguingly, in B-ALL cells the drug combination activated NF-κB p65 pro-apoptotic functions. In fact in B-cells, the combined treatment induced p65-HDAC1 association with consequent repression of the anti-apoptotic target genes, Bcl-xL and XIAP. Exposure to NEMO (IKKγ)-binding domain inhibitor peptide reduced the cytotoxic effects of bortezomib/CX-4945 treatment. Overall, our findings demonstrated that CK2 inhibition could be useful in combination with bortezomib as a novel therapeutic strategy in both T- and B-ALL.

Adolescent Adherence to Oral Therapy for Leukemia: A Focus Group Study

This secondary qualitative analysis of extant focus group data was performed to develop an understanding of suboptimal adherence to 6-mercaptopurine therapy in adolescents with acute lymphoblastic leukemia. Six participants, aged 16 to 23 years at the time of data collection, were interviewed about their adherence to oral maintenance chemotherapy during their treatment for acute lymphoblastic leukemia. The primary aim of the study was to understand the role of adolescent development in adolescents' perception of adherence to therapy. The secondary aim was to understand how factors other than development, including the features of the disease such as its chronic nature and family involvement, can affect treatment adherence to 6-mercaptopurine. Four broad themes emerged as critical elements in adolescent adherence to oral maintenance therapy: a desire for normalcy, egocentrism, concrete thinking, and parental involvement. Incorporation of these themes into clinical practice with adolescents may help increase adherence and improve clinical outcomes.

Impact of Socioeconomic Status on Timing of Relapse and Overall Survival for Children Treated on Dana-Farber Cancer Institute ALL Consortium Protocols (2000-2010)

BACKGROUND

Population-based evidence suggests that lower socioeconomic status (SES) negatively impacts the overall survival (OS) of children with leukemia; however, the relationships between SES and treatment-related mortality, relapse, and timing of relapse remain unclear.

PROCEDURE

We examined OS, event-free survival (EFS) and cumulative incidence (CI) and timing of relapse by community-level poverty for 575 children aged 1-18 years with newly diagnosed acute lymphoblastic leukemia (ALL) treated on consecutive phase III multicenter Dana-Farber Cancer Institute ALL Consortium Protocols between 2000 and 2010. Children were categorized into high- and low-poverty areas for the analysis using aggregate U.S. Census data linked to zip code.

RESULTS

Children living in high-poverty areas experienced a 5-year OS of 85% as compared with 92% for those in low-poverty areas (P = 0.02); poverty remained marginally significant (P = 0.07) after adjustment for immunophenotype, age, and white blood cell count. There were no differences detected in EFS or CI relapse by poverty area. However, 92% of the relapses observed in children from high-poverty areas occurred <36 months from complete remission, compared to 48% of those in children from low-poverty areas (P = 0.008).

CONCLUSIONS

U.S. children with ALL living in high-poverty areas have a higher risk of early relapse when compared with those living in low-poverty areas despite uniform treatment. This may in part explain decreased OS observed in these children. This finding highlights disparities in childhood cancer outcomes by SES despite uniform treatment. Further investigations of the mechanistic pathways underlying this finding are needed.

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

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

Modeling Chemotherapy Resistant Leukemia In Vitro

It is well established that the bone marrow microenvironment provides a unique site of sanctuary for hematopoietic diseases that both initiate and progress in this site. The model presented in the current report utilizes human primary bone marrow stromal cells and osteoblasts as two representative cell types from the marrow niche that influence tumor cell phenotype. The in vitro co-culture conditions described for human leukemic cells with these primary niche components support the generation of a chemoresistant subpopulation of tumor cells that can be efficiently recovered from culture for analysis by diverse techniques. A strict feeding schedule to prevent nutrient fluxes followed by gel type 10 cross-linked dextran (G10) particles recovery of the population of tumor cells that have migrated beneath the adherent bone marrow stromal cells (BMSC) or osteoblasts (OB) generating a "phase dim" (PD) population of tumor cells, provides a consistent source of purified therapy resistant leukemic cells. This clinically relevant population of tumor cells can be evaluated by standard methods to investigate apoptotic, metabolic, and cell cycle regulatory pathways as well as providing a more rigorous target in which to test novel therapeutic strategies prior to pre-clinical investigations targeted at minimal residual disease.

Childhood relapsed acute lymphoblastic leukemia: Biology and recent treatment progress

Acute lymphoblastic leukemia (ALL) is the most frequent cancer in children. Despite remarkable improvement in the prognosis of childhood ALL over the past few decades, the treatment of relapsed ALL is still challenging. The prognosis of first ALL relapse is associated with time of relapse after initial therapy, sites of relapse, and immunophenotype. More recently, response to treatment, which is evaluated by assessment of minimal residual disease (MRD), has been found to be clinically significant in relapsed ALL as well as in the initially diagnosed disease. Utilizing these factors, risk-oriented treatment stratification for first ALL relapse has been established. In the standard-risk group for first ALL relapse, intensification of conventional ALL-type therapy can provide a cure in approximately 70% of patients. It is important to assess MRD after reinduction therapy to determine the indications for stem cell transplantation in the standard-risk group. In contrast, no standardized therapy has been established for the high-risk group, which accounts for more than half of relapsed ALL patients. Recent studies have shed light on the clonal origin of relapsed ALL, which usually exists as a minor subclone at the time of initial diagnosis. Clonal selection and evolution take place during chemotherapy, resulting in distinct genetic and epigenetic characteristics of relapsed ALL, some of which are linked to drug resistance, a common and problematic feature of ALL after relapse. To overcome resistance to standard ALL-type therapy, and considering the heterogeneous biological background of high-risk relapsed ALL, innovative therapies using new agents are necessary.

Unusual sites of relapse in pre-B acute lymphoblastic leukemia

Relapses of acute lymphoblastic leukemia (ALL) in unusual sites can be challenging to diagnose. We present unusual relapses occurring in children with ALL treated in a single institution over a 22-year period. Of 172 relapses, 9 (5.2%) were at unusual sites (nonmarrow, testes, central nervous system). The most common site of relapse was ocular (66%). The median symptom-to-diagnosis interval was 20 days. Two of 9 children attained second remission. A possibility of relapse should be considered when evaluating unusual symptoms in a child with underlying ALL.

Outcome of central nervous system relapses in childhood acute lymphoblastic leukaemia--prospective open cohort analyses of the ALLR3 trial

The outcomes of Central Nervous System (CNS) relapses in children with acute lymphoblastic leukaemia (ALL) treated in the ALL R3 trial, between January 2003 and March 2011 were analysed. Patients were risk stratified, to receive a matched donor allogeneic transplant or fractionated cranial irradiation with continued treatment for two years. A randomisation of Idarubicin with Mitoxantrone closed in December 2007 in favour of Mitoxantrone. The estimated 3-year progression free survival for combined and isolated CNS disease were 40.6% (25·1, 55·6) and 38.0% (26.2, 49.7) respectively. Univariate analysis showed a significantly better survival for age <10 years, progenitor-B cell disease, good-risk cytogenetics and those receiving Mitoxantrone. Adjusting for these variables (age, time to relapse, cytogenetics, treatment drug and gender) a multivariate analysis, showed a poorer outcome for those with combined CNS relapse (HR 2·64, 95% CI 1·32, 5·31, p = 0·006 for OS). ALL R3 showed an improvement in outcome for CNS relapses treated with Mitoxantrone compared to Idarubicin; a potential benefit for matched donor transplant for those with very early and early isolated-CNS relapses.

TRIAL REGISTRATION

Controlled-Trials.com ISRCTN45724312.

Management of relapsed acute lymphoblastic leukemia in childhood with conventional and innovative approaches

PURPOSE OF REVIEW

To review and summarize the available evidence on factors predicting prognosis of children with relapsed acute lymphoblastic leukemia (ALL) and on the currently used treatment strategies, as well as on the most promising and innovative molecular or cellular therapies.

RECENT FINDINGS

Relapse still represents the most common cause of treatment failure, occurring in approximately 15-20% of childhood ALL. Risk-oriented standard salvage regimens are mostly based on combinations of the same agents incorporated in frontline therapies. Allogeneic hematopoietic stem cell transplantation (HSCT) is largely employed as postremission therapy, being superior to chemotherapy in high-risk patients. With conventional therapies including HSCT, 40-50% of children with relapsed ALL can be rescued. Thus, innovative approaches are needed to further improve the outcome of patients, especially when carrying poor prognostic factors. The last decade has witnessed the development of novel agents, including nucleoside analogues, anti-CD22 monoclonal antibodies and bi-specific, anti-CD3/CD19 antibodies, together with new formulations of existing chemotherapeutic agents and targeted molecules, such as tyrosine kinase inhibitors and FLT3 inhibitors.

SUMMARY

A significant proportion of children with relapsed ALL are salvaged by risk-oriented therapies. Novel agents should be integrated into combination regimens with the aim of further improving outcome of patients.

Role of integrin alpha4 in drug resistance of leukemia

Chemotherapeutic drug resistance in acute lymphoblastic leukemia (ALL) is a significant problem, resulting in poor responsiveness to first-line treatment or relapse after transient remission. Classical anti-leukemic drugs are non-specific cell cycle poisons; some more modern drugs target oncogenic pathways in leukemia cells, although in ALL these do not play a very significant role. By contrast, the molecular interactions between microenvironment and leukemia cells are often neglected in the design of novel therapies against drug resistant leukemia. It was shown however, that chemotherapy resistance is promoted in part through cell–cell contact of leukemia cells with bone marrow (BM) stromal cells, also called cell adhesion-mediated drug resistance (CAM-DR). Incomplete response to chemotherapy results in persistence of resistant clones with or without detectable minimal residual disease (MRD). Approaches for how to address CAM-DR and MRD remain elusive. Specifically, studies using anti-functional antibodies and genetic models have identified integrin alpha4 as a critical molecule regulating BM homing and active retention of normal and leukemic cells. Pre-clinical evidence has been provided that interference with alpha4-mediated adhesion of ALL cells can sensitize them to chemotherapy and thus facilitate eradication of ALL cells in an MRD setting. To this end, Andreeff and colleagues recently provided evidence of stroma-induced and alpha4-mediated nuclear factor-κB signaling in leukemia cells, disruption of which depletes leukemia cells of strong survival signals. We here review the available evidence supporting the targeting of alpha4 as a novel strategy for treatment of drug resistant leukemia.

How to treat relapsed acute lymphoblastic leukemia: transplant vs. conventional chemotherapy

Management of relapsed acute lymphoblastic leukemia (ALL) is challenging and far from satisfactory. The treatment approaches are often varied and controversial. The duration of first remission, site of relapse, immunophenotypic and molecular characteristics of relapsed disease and response to therapy influence treatment outcome. There are three main therapeutic options i.e., chemotherapy alone, induction chemotherapy followed by HLA matched allogeneic transplant and palliation. These may be chosen based on the above mentioned factors. The response to therapy may be evaluated morphologically or by minimal residual disease (MRD). Persistence of MRD, as assessed by molecular techniques or through flowcytometry, clearly influences prognosis in children with relapsed ALL. It not only helps in identifying the subset of patients likely to benefit from allogeneic bone marrow transplant (ABMT) but also in determining the timing of transplant. Patients with non-T phenotype, with late relapsing disease and good response to re-induction therapy have been shown to do equally well with chemotherapy alone. On the other hand patients with early relapse and poor initial response are selected for ABMT. With the improvement in supportive care, better selection of HLA match donors and better immunosuppressive therapies, transplant related mortality has decreased considerably. Despite all of these overall salvage rates are still poor and novel agents are being tested in various trials to establish their role in relapsed ALL therapy.

Kidney and pancreatic extramedullary relapse in adult acute lymphoblastic leukemia: a case report and review of the literature

Extramedullary relapse of acute lymphoblastic leukemia (ALL) is rare and has been primarily reported in pediatric patients or hematopoietic stem cell transplant recipients. We report a case of a 62-year-old woman who presented with relapsed ALL involving her kidneys, pancreas, and bone marrow 2 years after completing chemotherapy with a standard ALL protocol. Unfortunately, her extramedullary disease progressed despite treatment. To the best of our knowledge, this is the first reported case of extramedullary relapse of B-cell ALL to the kidneys and pancreas occurring in an adult patient who had not previously undergone a hematopoietic stem cell transplant. A literature review of kidney and pancreatic extramedullary relapse in ALL is also included.

Outcomes of treatment for relapsed acute lymphoblastic leukaemia in children with Down syndrome

Children with Down syndrome (DS) have a greater risk for developing both acute lymphoblastic leukaemia (ALL) and significant adverse effects of chemotherapy. We investigated their outcome with, and tolerance of, treatment protocols for relapsed ALL optimized in the paediatric population without DS. Probability of survival and causes of treatment failure were determined for 49 children with DS and a matched cohort of 98 children without DS among 2160 children treated for relapsed ALL in clinical trials conducted by the Berlin-Frankfurt-Münster ALL Relapse Study Group between 1983 and 2012. Despite more favourable ALL relapse characteristics, children with DS experienced lower event-free (EFS) and overall survival (OS) than the control group without DS (EFS 17 ± 08% vs. non-DS 41 ± 06%, P = 0·006; OS 17 ± 09% vs. non-DS 51 ± 06%, P < 0·001). Children with DS developed more frequently fatal complications of treatment (34 ± 07% vs. non-DS 10 ± 04%, P < 0·001). During the last decade, EFS and OS were no longer significantly different in children with and without DS (EFS 31 ± 09% vs. 36 ± 09%, P = 0·399; OS 31 ± 12% vs. 53 ± 09%, P = 0·151). DS proved an independent prognostic factor of outcome after ALL relapse. Induction deaths and treatment-related mortality but not subsequent relapse were the main barrier to successful outcomes of relapse therapy in children with DS.

Activating mutations in the NT5C2 nucleotidase gene drive chemotherapy resistance in relapsed ALL

Acute lymphoblastic leukemia (ALL) is an aggressive hematological tumor resulting from the malignant transformation of lymphoid progenitors. Despite intensive chemotherapy, 20% of pediatric patients and over 50% of adult patients with ALL do not achieve a complete remission or relapse after intensified chemotherapy, making disease relapse and resistance to therapy the most substantial challenge in the treatment of this disease. Using whole-exome sequencing, we identify mutations in the cytosolic 5'-nucleotidase II gene (NT5C2), which encodes a 5'-nucleotidase enzyme that is responsible for the inactivation of nucleoside-analog chemotherapy drugs, in 20/103 (19%) relapse T cell ALLs and 1/35 (3%) relapse B-precursor ALLs. NT5C2 mutant proteins show increased nucleotidase activity in vitro and conferred resistance to chemotherapy with 6-mercaptopurine and 6-thioguanine when expressed in ALL lymphoblasts. These results support a prominent role for activating mutations in NT5C2 and increased nucleoside-analog metabolism in disease progression and chemotherapy resistance in ALL.

Where do we stand in the treatment of relapsed acute lymphoblastic leukemia?

Acute lymphoblastic leukemia (ALL) is the most common and one of the most treatable cancers in children. Although the majority of children with ALL are now cured, 10%-20% of patients are predicted to relapse and outcomes with salvage therapy have been disappointing, with approximately only one-third of children surviving long-term after disease recurrence. Several prognostic factors have been identified, with timing of recurrence relative to diagnosis and site of relapse emerging as the most important variables. Despite heterogeneity in the elements of salvage therapy that are delivered in trials conducted internationally, outcomes have been remarkably similar and have remained static. Because most intensive salvage regimens have reached the limit of tolerability, current strategies are focusing on identifying new agents tailored to the unique biology of relapsed disease and identifying methods to develop these agents efficiently for clinical use. Recently, high-resolution genomic analyses of matched pairs of diagnostic and relapse bone marrow samples are emerging as a promising tool for identifying pathways that impart chemoresistance.

Relapsed or refractory pediatric acute lymphoblastic leukemia: current and emerging treatments

Relapsed acute lymphoblastic leukemia (ALL) represents a major cause of morbidity and mortality in pediatrics. With contemporary chemotherapy, >85% of patients with newly diagnosed ALL survive. Unfortunately, 20% of these patients will relapse and for these children, outcomes remain poor despite our best known chemotherapy protocols. Most of these children will achieve a second complete remission, but maintaining this remission remains difficult. Because relapsed ALL is such a significant cause of morbidity and mortality, it is the focus of much research interest. Efforts have been made and continue to focus on understanding the underlying biology that drives relapse. The role of hematopoietic stem cell transplantation in relapsed ALL remains unclear, but many clinicians still favor this for high-risk patients given the poor prognosis with current chemotherapy alone. It is important to use new drugs with little cross-resistance in the treatment of relapsed ALL. New classes of agents are currently being studied. We also discuss prognostic factors and the biology of relapsed ALL.

Prognosis and outcome of relapsed acute lymphoblastic leukemia: a Hong Kong Pediatric Hematology and Oncology Study Group report

BACKGROUND

In 2000, the Hong Kong Pediatric Hematology Oncology Study Group started a new relapsed acute lymphoblastic leukemia (ALL) treatment protocol based on modified ALL-REZ BFM 96 protocol aiming at improving the treatment outcome in Chinese children.

PROCEDURE

All patients in Hong Kong with first relapse of childhood ALL were included. Patients were stratified into four risk groups (S1, S2, S3, and S4) and the treatment consisted of intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation, if indicated.

RESULTS

Fifty-six patients were recruited and median age at diagnosis of ALL was 4.6 (range, 0.3-17) years. The median time from initial diagnosis to relapse was 2.5 (range, 0.3-9.1) years and follow-up time was 2.7 (range, 0-9.9) years. Forty-nine patients (87.5%) achieved second complete remission (CR2). CR2 rates for S1, S2, S3, and S4 groups were 100%, 93%, 90%, and 67%, respectively. Five-year overall survival (OS) was 50.5 ± 6.9% and event-free survival (EFS) was 41.5 ± 7.1%. There was no significant difference in survival among S1, S2, and S3 groups but S4 patients performed significantly worse with 5-year OS and EFS of 8% and 0%, respectively.

CONCLUSION

Children with relapsed ALL of S1-S3 risk groups could be successfully treated with intensified treatment protocol. The S4 high risk group needs more innovative approach to improve treatment outcome.