Integration of ruxolitinib into dose-intensified therapy targeted against a novel JAK2 F694L mutation in B-precursor acute lymphoblastic leukemia

Clinical features and prognosis of pediatric acute lymphocytic leukemia with JAK-STAT pathway genetic abnormalities: a case series

The objective of this study is to explore the clinical features and outcomes of pediatric patients with acute lymphoblastic leukemia (ALL) harboring JAK-STAT signaling pathway genetic abnormalities. This retrospective case series examined the clinical data of pediatric patients diagnosed with ALL harboring JAK-STAT pathway genetic abnormality at the Children's Hospital of the Capital Institute of Pediatrics between January 2016 and January 2022. Bone marrow next-generation sequencing was used to reveal the JAK pathway abnormalities. Descriptive statistics were used. From 432 children with ALL during the study period, eight had JAK-STAT pathway genetic abnormalities. Regarding immunotyping, there were four patients with common-B cell types and one with pre-B cell type. The three patients with T-ALL had early T-cell precursor(ETP) type, pre-T cell type, and T cell type. Gene mutations were more common than fusion genes. There was no central nervous system involvement in eight patients. All patients were considered at least at intermediate risk before treatments. Four patients underwent hematopoietic stem cell transplantation (HSCT). One child had a comprehensive relapse and died. The child had a severe infection and could not tolerate high-intensity chemotherapy. Another child relapsed 2 years after HSCT and died. Disease-free survival was achieved in six children. JAK-STAT pathway genetic abnormalities in pediatric Ph-like ALL are rare. Special attention should be paid to treatment-related complications, such as infection and combination therapy (chemotherapy, small molecule targeted drugs, immunotherapy, etc.) to reduce treatment-related death and improve long-term quality of life.

BCR::ABL1-like acute lymphoblastic leukaemia: a single institution experience on identification of potentially therapeutic targetable cases

BACKGROUND

BCR::ABL1-like acute lymphoblastic leukaemia (BCR::ABL1-like ALL) is characterized by inferior outcomes. Current efforts concentrate on the identification of molecular targets to improve the therapy results. The accessibility to next generation sequencing, a recommended diagnostic method, is limited. We present our experience in the BCR::ABL1-like ALL diagnostics, using a simplified algorithm.

RESULTS

Out of 102 B-ALL adult patients admitted to our Department in the years 2008-2022, 71 patients with available genetic material were included. The diagnostic algorithm comprised flow cytometry, fluorescent in-situ hybridization, karyotype analysis and molecular testing with high resolution melt analysis and Sanger Sequencing. We recognized recurring cytogenetic abnormalities in 32 patients. The remaining 39 patients were screened for BCR::ABL1-like features. Among them, we identified 6 patients with BCR::ABL1-like features (15.4%). Notably, we documented CRLF2-rearranged (CRLF2-r) BCR::ABL1-like ALL occurrence in a patient with long-term remission of previously CRLF2-r negative ALL.

CONCLUSIONS

An algorithm implementing widely available techniques enables the identification of BCR::ABL1-like ALL cases in settings with limited resources.

Philadelphia-like acute lymphoblastic leukemia: the journey from molecular background to the role of bone marrow transplant-review article

Philadelphia chromosome-like (Ph-like) ALL is a recent subtype of acute lymphoblastic leukemia. Although it does not express the BCR-ABL fusion gene, it has a behavior like true BCR/ABL1-positive cases. This subtype harbors different molecular alterations most commonly CRLF2 rearrangements. Most cases of Ph-like ALL are associated with high white blood cell count, high minimal residual disease level after induction therapy, and high relapse rate. Efforts should be encouraged for early recognition of Ph-like ALL to enhance therapeutic strategies. Recently, many trials are investigating the possibility of adding the tyrosine kinase inhibitor (TKI) to chemotherapy to improve clinical outcomes. The role and best timing of allogeneic bone marrow transplant in those cases are still unclear. Precision medicine should be implemented in the treatment of such cases. Here in this review, we summarize the available data on Ph-like ALL.

Novel pharmacological and dietary approaches to target mTOR in B-cell acute lymphoblastic leukemia

High-risk subtypes of B-cell acute lymphoblastic leukemia (B-ALL) are frequently associated with aberrant activation of tyrosine kinases (TKs). These include Ph+ B-ALL driven by BCR-ABL, and Ph-like B-ALL that carries other chromosomal rearrangements and/or gene mutations that activate TK signaling. Currently, the tyrosine kinase inhibitor (TKI) dasatinib is added to chemotherapy as standard of care in Ph+ B-ALL, and TKIs are being tested in clinical trials for Ph-like B-ALL. However, growth factors and nutrients in the leukemia microenvironment can support cell cycle and survival even in cells treated with TKIs targeting the driving oncogene. These stimuli converge on the kinase mTOR, whose elevated activity is associated with poor prognosis. In preclinical models of Ph+ and Ph-like B-ALL, mTOR inhibitors strongly enhance the anti-leukemic efficacy of TKIs. Despite this strong conceptual basis for targeting mTOR in B-ALL, the first two generations of mTOR inhibitors tested clinically (rapalogs and mTOR kinase inhibitors) have not demonstrated a clear therapeutic window. The aim of this review is to introduce new therapeutic strategies to the management of Ph-like B-ALL. We discuss novel approaches to targeting mTOR in B-ALL with potential to overcome the limitations of previous mTOR inhibitor classes. One approach is to apply third-generation bi-steric inhibitors that are selective for mTOR complex-1 (mTORC1) and show preclinical efficacy with intermittent dosing. A distinct, non-pharmacological approach is to use nutrient restriction to target signaling and metabolic dependencies in malignant B-ALL cells. These two new approaches could potentiate TKI efficacy in Ph-like leukemia and improve survival.

Clinical screening for Ph-like ALL and the developing role of TKIs

Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) is a common subtype of B-lineage acute lymphoblastic leukemia (B-ALL) with increasing frequency across the age spectrum. Characterized by a kinase-activated gene expression profile and driven by a variety of genetic alterations involving cytokine receptors and kinases, Ph-like ALL is associated with high rates of residual disease and relapse in patients treated with conventional chemotherapy. In this case-based review, we describe the biology of the 2 major ABL-class and JAK pathway genetic subtypes of Ph-like ALL, discuss current diagnostic testing methodologies, and highlight targeted inhibitor and chemo/immunotherapy approaches under clinical investigation in children, adolescents, and adults with these high-risk leukemias.

Efficacy of ruxolitinib in acute lymphoblastic leukemia: A systematic review

Philadelphia-like acute lymphoblastic leukemia (Ph-like ALL) is a high-risk molecular subtype with a gene expression profile similar to Philadelphia-positive ALL, but not harboring the BCR-ABL1 gene fusion. We aimed to investigate the efficacy of target therapy with the Janus kinase inhibitor, ruxolitinib, in patients with Ph-like ALL and molecular signature of JAK-STAT signaling pathway. A systematic search of the literature was performed to identify reports concerning administration of ruxolitinib in Ph-like ALL patients. Additionally, Polish Pediatric ALL registries were searched for patients with Ph-like ALL treated with ruxolitinib. Extracted information included epidemiological background, somatic aberrations, treatment response, and patient outcome. After PubMed database search, twelve patients were identified, and one was identified in the Polish Pediatric ALL registry. In nine patients gene fusions affecting JAK2 (n = 7) and EPOR (n = 2) were detected. Surface overexpression of CRLF2 and IKZF1 deletions were observed in two and three patients, respectively. Induction failure occurred in all the patients. Therapy with ruxolitinib led to complete (n = 7) and partial (n = 2) remission, in three individuals no information was found. Based on the limited number of studies describing the efficacy of ruxolitinib as an additional compound administrated with standard ALL therapy, we conclude that this approach can be considered in patients with aberrations activating JAK-STAT pathway.

JAK2 Alterations in Acute Lymphoblastic Leukemia: Molecular Insights for Superior Precision Medicine Strategies

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer, arising from immature lymphocytes that show uncontrolled proliferation and arrested differentiation. Genomic alterations affecting Janus kinase 2 (JAK2) correlate with some of the poorest outcomes within the Philadelphia-like subtype of ALL. Given the success of kinase inhibitors in the treatment of chronic myeloid leukemia, the discovery of activating JAK2 point mutations and JAK2 fusion genes in ALL, was a breakthrough for potential targeted therapies. However, the molecular mechanisms by which these alterations activate JAK2 and promote downstream signaling is poorly understood. Furthermore, as clinical data regarding the limitations of approved JAK inhibitors in myeloproliferative disorders matures, there is a growing awareness of the need for alternative precision medicine approaches for specific JAK2 lesions. This review focuses on the molecular mechanisms behind ALL-associated JAK2 mutations and JAK2 fusion genes, known and potential causes of JAK-inhibitor resistance, and how JAK2 alterations could be targeted using alternative and novel rationally designed therapies to guide precision medicine approaches for these high-risk subtypes of ALL.

BCR/ABL1-Like Acute Lymphoblastic Leukemia: From Diagnostic Approaches to Molecularly Targeted Therapy

BACKGROUND

BCR/ABL1-like acute lymphoblastic leukemia is a newly recognized high-risk subtype of ALL, characterized by the presence of genetic alterations activating kinase and cytokine receptor signaling. This subtype is associated with inferior outcomes, compared to other B-cell precursor ALL.

SUMMARY

The recognition of BCR/ABL1-like ALL is challenging due to the complexity of underlying genetic alterations. Rearrangements of CRLF2 are the most frequent alteration in BCR/ABL1-like ALL and can be identified by flow cytometry. The identification of BCR/ABL1-like ALL can be achieved with stepwise algorithms or broad-based testing. The main goal of the diagnostic analysis is to detect the underlying genetic alterations, which are critical for the diagnosis and targeted therapy.

KEY MESSAGES

The aim of the manuscript is to review the available data on BCR/ABL1-like ALL characteristics, diagnostic algorithms, and novel, molecularly targeted therapeutic options.

Diagnosis and Treatment of Myeloproliferative Neoplasms With PCM1-JAK2 Rearrangement: Case Report and Literature Review

Myeloproliferative neoplasm (MPN) with PCM1-JAK2 rearrangement is a rare disease with poor prognosis and lacks uniform treatment guidelines. Several studies confirmed the efficacy of ruxolitinib in hematological malignancies with PCM1-JAK2 fusion, but the efficacy is variable. Here, we report two patients diagnosed with MPN with PCM1-JAK2 fusion who were treated with ruxolitinib-based regimen, including the first case of ruxolitinib combined with pegylated interferon (Peg-IFN), and we conduct a literature review. We found that ruxolitinib combined with Peg-IFN is an effective treatment option in the case of poor efficacy of ruxolitinib monotherapy.

Clinical Efficacy of Ruxolitinib Monotherapy and Haploidentical Hematopoeitic Stem Cell Transplantation in a Child with Philadelphia Chromosome-like Relapsed/Refractory acute lymphoblastic leukemia

INTRODUCTION

(Ph-like) ALL is a subset of leukemia which has a gene expression profile similar to Ph+disease, but without the presence of BCR-ABL1 translocation.

CASE DESCRIPTION

We reported an exceptional case of a child with relapsed Ph-like ALL with IKZF1 gene deletion treated with high-dose ruxolitinib as monotherapy, after multi-agent chemotherapy. He remains in continued MRD-negative leukemia remission with full donor chimerism at 12 months post-HSCT.

DISCUSSION

The circumstance that makes our case featured is the usage of ruxolitinib as monotherapy. This report, we believe, is a pioneering report for a frequent disease with a high risk of failure for the outcome.

Genomic landscape of B-other acute lymphoblastic leukemia in an adult retrospective cohort with a focus on BCR-ABL1-like subtype

INTRODUCTION

BCR-ABL1-like acute lymphoblastic leukemia (ALL) is a high-risk disease with a complex genomic background. Though extensively studied, data on the frequency and mutual associations of present mutations are still incomplete in adult patients. This retrospective study aims to map the genomic landscape of B-other ALL in a cohort of adult patients with a focus on the BCR-ABL1-like ALL subtype.

METHODS

We analyzed bone marrow and peripheral blood samples of adult B-other ALL patients treated consecutively at three major Czech teaching hospitals. Samples were analyzed by cytogenetic methods, gene expression profiling, multiplex ligation-dependent probe amplification (MLPA), and next-generation sequencing (NGS).

RESULTS

Fifty-eight B-other ALL patients (not BCR-ABL1, KMT2A-rearranged, ETV6-RUNX1, TCF3-PBX1, or iAMP21) were included in the study. Median follow-up was 23.8 months. Samples from 33 patients were available for a gene expression analysis, 48.9% identified as BCR-ABL1-like ALL. Of the BCR-ABL1-like ALL cases, 18.8% harbored IGH-CRLF2 and 12.5% P2RY8-CRLF2 fusion gene. We observed a higher MRD failure rate in BCR-ABL1-like than in non-BCR-ABL1-like ALL patients after the induction treatment (50.0 vs. 13.3%, p=.05). There was a trend to worse progression-free and overall survival in the BCR-ABL1-like group, though not statistically significant. Deletions in IKZF1 gene were found in 31.3% of BCR-ABL1-like cases. Patients with concurrent IKZF1 and CDKN2A/B, PAX5 or PAR1 region deletions (IKZF1^plus profile) had significantly worse progression-free survival than those with sole IKZF1 deletion or IKZF1 wild-type (p=.02). NGS analysis was performed in 54 patients and identified 99 short variants in TP53, JAK2, NRAS, PAX5, CREBBP, NF1, FLT3, ATM, KRAS, RUNX1, and other genes. Seventy-five of these gene variants have not yet been described in B-cell precursor ALL to date.

CONCLUSION

This study widens existing knowledge of the BCR-ABL1-like and B-other ALL genomic landscape in the adult population, supports previous findings, and identifies a number of novel gene variants.

JAK Inhibitors for the Treatment of Pediatric Alopecia Areata

Alopecia areata is a common autoimmune condition that disproportionately affects children and can significantly hinder quality of life. Few safe and effective therapies are available for the treatment of severely affected pediatric patients. JAK inhibitors have been recently established as an effective and well-tolerated therapy in adults, but there are limited data regarding the use of JAK inhibitors to treat alopecia areata in children. Here, we review the available literature regarding the use of JAK inhibitors in children in dermatology and across other medical disciplines.

Optimal therapy for adolescents and young adults with acute lymphoblastic leukemia-current perspectives

Adolescents and young adults (AYA) with acute lymphoblastic leukemia (ALL) have worse prognosis than children. Differing biology of ALL may account for some of this disparity in outcome, with AYA patients having far lower incidence of good risk cytogenetic abnormalities, and higher proportion of patients with genetic lesions associated with inferior survival such as Ph-like ALL. Actual chemotherapy may also contribute to differences in outcome. Retrospective studies have shown that AYA patients treated on pediatric-based regimens had higher survival than those treated with adult regimens; the superiority of pediatric protocols has also been proven in several prospective comparative trials. Increase in rate of enrollment of AYA patients in clinical trials may further improve outcome. Cure based on chemotherapy may further limit the role of allogeneic hematopoietic cell transplantation (HCT) in AYA patients. The unique biology of AYA ALL may allow for novel methods of targeted therapy, while immunotherapy, the efficacy of which has been proven for both children and adults, may also play a major role in the treatment of relapsed/refractory ALL.

High incidence of RAS pathway mutations among sentinel genetic lesions of Korean pediatric BCR-ABL1-like acute lymphoblastic leukemia

INTRODUCTION

Recent advances in genetic analysis have led to the discovery of novel genetic subtypes of precursor B-cell acute lymphoblastic leukemia (B-ALL) with prognostic relevance. In this study, we studied a cohort of pediatric B-ALL patients to retrospectively determine the incidence of patients harboring novel genetic subtypes, as well as their outcome.

METHODS

B-ALL patients (N = 190) diagnosed in a single Korean hospital were included in the study. Patients' medical records were reviewed for data on established genetic abnormalities and outcome. CRLF2 expression was analyzed by quantitative RT-PCR. Anchored multiplex PCR-based enrichment was used to detect fusions and point mutations in 81 ALL-related genes.

RESULTS

Incidence of established recurrent genetic subtypes was as follows: high hyperdiploidy (21.6%), ETV6-RUNX1 (21.6%), BCR-ABL1 (7.9%), KMT2A rearrangement (7.4%) TCF3-PBX1/TCF3-HLF (7.4%), and hypodiploidy (1.1%). Incidence of new genetic subtypes was as follows: BCR-ABL1-like (13.2%), ETV6-RUNX1-like (2.1%), EWSR1-ZNF384 (1.1%), and iAMP21 (1.1%). Median age at diagnosis of BCR-ABL1-like ALL was 6.8 years. According to type of genetic abnormality, BCR-ABL1-like ALL was divided into ABL class (12%), CRLF2 class (8%), JAK-STAT class (12%), and RAS class (68%). The 5-year event-free survival (EFS) of BCR-ABL1-like patients was significantly inferior to non-BCR-ABL1-like low- and standard-risk patients (71.5 ± 9.1% vs 92.5 ± 3.2%, P = .001) and comparable to non-BCR-ABL1-like high (75.2 ± 6.2%) and very high-risk patients (56.8 ± 7.4%). All four ETV6-RUNX1-like patients survived event-free.

CONCLUSION

Analogous to previous studies, incidence of BCR-ABL1-like ALL in our cohort was 13.2% with outcome comparable to high and very high-risk patients. A significantly high number of RAS class mutations was a distinct feature of our BCR-ABL1-like ALL group.

New biomarkers and therapeutic strategies in acute lymphoblastic leukemias: Recent advances

Acute lymphoblastic leukemia (ALL) represents a heterogeneous group of hematologic malignancies, and it is normally characterized by an aberrant proliferation of immature lymphoid cells. Moreover, dysregulation of multiple signaling pathways that normally regulate cellular transcription, growth, translation, and proliferation is frequently encountered in this malignancy. ALL is the most frequent tumor in childhood, and adult ALL patients still correlate with poor survival. This review focuses on modern therapies in ALL that move beyond standard chemotherapy, with a particular emphasis on immunotherapeutic approaches as new treatment strategies. Bi-specific T-cell Engagers (BiTE) antibodies, the chimeric antigen receptor (CAR)-T cells, or CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats [CRISPR]-associated nuclease 9) represent other new innovative approaches for this disease. Target and tailored therapy could make the difference in previously untreatable cases, i.e., precision and personalized medicine. Clinical trials will help to select the most efficient novel therapies in ALL management and to integrate them with existing treatments to achieve durable cures.

How I diagnose and manage Philadelphia chromosome-like acute lymphoblastic leukemia

Advances in our understanding of mechanisms of leukemogenesis and driver mutations in acute lymphoblastic leukemia (ALL) lead to a more precise and informative sub-classification, mainly of B-cell ALL. In parallel, in recent years, novel agents have been approved for the therapy of B-cell ALL, and many others are in active clinical research. Among the newly recognized disease subtypes, Philadelphia-chromosome-like ALL is the most heterogeneous and thus, diagnostically challenging. Given that this subtype of B-cell ALL is associated with a poorer prognosis, improvement of available therapeutic approaches and protocols is a burning issue. Herein, we summarize, in a clinically relevant manner, up-to-date information regarding diagnostic strategies developed for the identification of patients with Philadelphia-chromosome-like ALL. Common therapeutic dilemmas, presented as several case scenarios, are also discussed. It is currently acceptable that patients with B-cell ALL, treated with an aim of cure, irrespective of their age, be evaluated for a Philadelphia-chromosome-like signature as early as possible. Following Philadelphia-chromosome-like recognition, a higher risk of resistance or relapse must be realized and treatment should be modified based on the patient’s specific genetic driver and clinical features. However, while active targeted therapeutic options are limited, there is much more to do than just prescribe a matched inhibitor to the identified mutated driver genes. In this review, we present a comprehensive evidence-based approach to the diagnosis and management of Philadelphia-chromosome-like ALL at different time-points during the disease course.

Precision medicine approaches may be the future for CRLF2 rearranged Down Syndrome Acute Lymphoblastic Leukaemia patients

Breakthrough studies over the past decade have uncovered unique gene fusions implicated in acute lymphoblastic leukaemia (ALL). The critical gene, cytokine receptor-like factor 2 (CRLF2), is rearranged in 5-16% of B-ALL, comprising 50% of Philadelphia-like ALL and cooperates with genomic lesions in the Jak, Mapk and Ras signalling pathways. Children with Down Syndrome (DS) have a predisposition to developing CRLF2 rearranged-ALL which is observed in 60% of DS-ALL patients. These patients experience a poor survival outcome. Mutations of genes involved in epigenetic regulation are more prevalent in DS-ALL patients than non-DS ALL patients, highlighting the potential for alternative treatment strategies. DS-ALL patients also suffer greater treatment-related toxicity from current ALL treatment regimens compared to non-DS-ALL patients. An increased gene dosage of critical genes on chromosome 21 which have roles in purine synthesis and folate transport may contribute. As the genomic landscape of DS-ALL patients is different to non-DS-ALL patients, targeted therapies for individual lesions may improve outcomes. Therapeutically targeting each rearrangement with targeted or combination therapy that will perturb the transforming signalling pathways will likely improve the poor survival rates of this subset of patients.

New biological and genetic classification and therapeutically relevant categories in childhood B-cell precursor acute lymphoblastic leukemia

Traditionally, genetic abnormalities detected by conventional karyotyping, fluorescence in situ hybridization, and polymerase chain reaction divided childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) into well-established genetic subtypes. This genetic classification has been prognostically relevant and thus used for the risk stratification of therapy. Recently, the introduction of genome-wide approaches, including massive parallel sequencing methods (whole-genome, -exome, and -transcriptome sequencing), enabled extensive genomic studies which, together with gene expression profiling, largely expanded our understanding of leukemia pathogenesis and its heterogeneity. Novel BCP-ALL subtypes have been described. Exact identification of recurrent genetic alterations and their combinations facilitates more precise risk stratification of patients. Discovery of targetable lesions in subsets of patients enables the introduction of new treatment modalities into clinical practice and stimulates the transfer of modern methods from research laboratories to routine practice.

Inclusion of special populations in clinical research: important considerations and guidelines

BACKGROUND

Trials that involve human participants call for experiments or observations that are performed in a clinical research setting. Currently, there are over 16,000 clinical trials open in the United States. Despite continuing efforts to include "special populations" in clinical trials, there are gaps in participation for people who are either minors or elderly adults, are from historically under-represented minorities, or live in rural communities. The inclusion of these special populations in clinical trials research is essential for conclusions that benefit all populations. Data suggest that study partic-ipation rates for special populations have fallen to levels that could endanger the successful performance of some types of research. This is particularly concerning in the 21st century, where demographic trends in the United States continue to shift towards an older and Hispanic population with fewer rural dwellers. Trends in New Mexico and other minority-majority states mirror many of these shifts.

RELEVANCE FOR PATIENTS

In this review, we highlight improvement strategies for enhanced clinical trial participation by members of special populations. Key drivers for disparate clinical trials participation and outcomes often include differences in genetics, physiology, and perceptions of mistrust towards researchers. To overcome these barriers, we focus on best practices in recruitment strategies from the perspectives of the participants, the researchers and the institutions that support clinical trials.

A phase II study of the oral JAK1/JAK2 inhibitor ruxolitinib in advanced relapsed/refractory Hodgkin lymphoma

JAK2 constitutive activation/overexpression is common in classical Hodgkin lymphoma, and several cytokines stimulate Hodgkin lymphoma cells by recognizing JAK1-/JAK2-bound receptors. JAK blockade may thus be therapeutically beneficial in Hodgkin lymphoma. In this phase II study we assessed the safety and efficacy of ruxolitinib, an oral JAK1/2 inhibitor, in patients with relapsed/refractory Hodgkin lymphoma. The primary objective was overall response rate according to the International Harmonization Project 2007 criteria. Thirty-three patients with advanced disease (median number of prior lines of treatment: 5; refractory: 82%) were included; nine (27.3%) received at least six cycles of ruxolitinib and six (18.2%) received more than six cycles. The overall response rate after six cycles was 9.4% (3/32 patients). All three responders had partial responses; another 11 patients had transient stable disease. Best overall response rate was 18.8% (6/32 patients). Rapid alleviation of B-symptoms was common. The median duration of response was 7.7 months, median progression-free survival 3.5 months (95% CI: 1.9–4.6), and the median overall survival 27.1 months (95% CI: 14.4–27.1). Forty adverse events were reported in 14/33 patients (42.4%). One event led to treatment discontinuation, while 87.5% of patients recovered without sequelae. Twenty-five adverse events were grade 3 or higher. These events were mostly anemia (n=11), all considered related to ruxolitinib. Other main causes of grade 3 or higher adverse events included lymphopenia and infections. Of note, no cases of grade 4 neutropenia or thrombocytopenia were observed. Ruxolitinib shows signs of activity, albeit short-lived, beyond a simple anti-inflammatory effect. Its limited toxicity suggests that it has the potential to be combined with other therapeutic modalities. ClinicalTrials.gov: NCT01877005

Infections in Children on Biologics

Biologics target various pathways to modify immunologic activity. Biologic use to treat pediatric patients continues to expand; but limited data exist regarding infectious complications of these agents, especially for newer agents. Infectious events reported in the literature for pediatric patients indicate that a variety of bacterial, mycobacterial, viral, and fungal infections can occur. Further pediatric-specific reports are needed to fill knowledge gaps in the complications related to these agents.

How should we treat the AYA patient with newly diagnosed ALL?

Adolescent and young adult (AYA) patients with acute lymphoblastic leukaemia (ALL) are recognized as a unique population with specific characteristics and needs. In adolescents aged 15-20 years old, the use of full paediatric protocols is supported by many comparative studies of paediatric and adult cooperative groups. In young adults, growing evidence suggests that paediatric-inspired approaches may also improve outcomes and lead to long-term survival rates of almost 70%. In the last decade, better knowledge of ALL oncogenic landscape, age distribution, and minimal residual disease prognostic impact have improved risk stratification. New targets have emerged mostly in the heterogeneous subgroup of Philadelphia-like ALL and will require both in-depth molecular investigations and specific evaluations in rare subgroups of ALL. The remaining gap with the excellent results reported in children has many other contributing factors that should not be underestimated including late or difficult access to care, or poor adherence to treatment.

BCR-ABL1-like acute lymphoblastic leukaemia: From bench to bedside

Acute lymphoblastic leukaemia (ALL) occurs in approximately 1:1500 children and is less frequently found in adults. The most common immunophenotype of ALL is the B cell lineage and within B cell precursor ALL, specific genetic aberrations define subtypes with distinct biological and clinical characteristics. With more advanced genetic analysis methods such as whole genome and transcriptome sequencing, novel genetic subtypes have recently been discovered. One novel class of genetic aberrations comprises tyrosine kinase-activating lesions, including translocations and rearrangements of tyrosine kinase and cytokine receptor genes. These newly discovered genetic aberrations are harder to detect by standard diagnostic methods such as karyotyping, fluorescent in situ hybridisation (FISH) or polymerase chain reaction (PCR) because they are diverse and often cryptic. These lesions involve one of several tyrosine kinase genes (among others, v-abl Abelson murine leukaemia viral oncogene homologue 1 (ABL1), v-abl Abelson murine leukaemia viral oncogene homologue 2 (ABL2), platelet-derived growth factor receptor beta polypeptide (PDGFRB)), each of which can be fused to up to 15 partner genes. Together, they compose 2-3% of B cell precursor ALL (BCP-ALL), which is similar in size to the well-known fusion gene BCR-ABL1 subtype. These so-called BCR-ABL1-like fusions are mutually exclusive with the sentinel translocations in BCP-ALL (BCR-ABL1, ETV6-RUNX1, TCF3-PBX1, and KMT2A (MLL) rearrangements) and have the promising prospect to be sensitive to tyrosine kinase inhibitors similar to BCR-ABL1. In this review, we discuss the types of tyrosine kinase-activating lesions discovered, and the preclinical and clinical evidence for the use of tyrosine kinase inhibitors in the treatment of this novel subtype of ALL.

Novel therapy for childhood acute lymphoblastic leukemia

INTRODUCTION

During recent decades, the prognosis of childhood acute lymphoblastic leukemia (ALL) has improved dramatically, nowadays, reaching a cure rate of almost 90%. These results are due to a better management and combination of old therapies, refined risk-group stratification and emergence of minimal residual disease (MRD) combined with treatment's intensification for high-risk subgroups. However, the subgroup of patients with refractory/relapsed ALL still presents a dismal prognosis indicating necessity for innovative therapeutic approaches. Areas covered: We performed an exhaustive review of current first-line therapies for childhood ALL in the worldwide main consortia, summarized the major advances for front-line and relapse treatment and highlighted recent and promising innovative therapies with an overview of the most promising ongoing clinical trials. Expert opinion: Two major avenues marked the beginning of 21^st century. First, is the introduction of tyrosine-kinase inhibitor coupled to chemotherapy for treatment of Philadelphia positive ALL opening new treatment possibilities for the recently identified subgroup of Ph-like ALL. Second, is the breakthrough of immunotherapy, notably CAR T-cell and specific antibody-based therapy, with remarkable success observed in initial studies. This review gives an insight on current knowledge in these innovative therapeutic directions, summarizes currently ongoing clinical trials and addresses challenges these approaches are faced with.