Distinct impact of imatinib on growth at prepubertal and pubertal ages of children with chronic myeloid leukemia

Screening and interventional strategies for the late effects and toxicities of hematological malignancy treatments in pediatric survivors

INTRODUCTION

Advancements in pediatric cancer treatment have increased patient survival rates; however, childhood cancer survivors may face long-term health challenges due to treatment-related effects on organs. Regular post-treatment surveillance and early intervention are crucial for improving the survivors' quality of life and long-term health outcomes. The present paper highlights the significance of late effects in childhood cancer survivors, particularly those with hematologic malignancies, stressing the importance of a vigilant follow-up approach to ensure better overall well-being.

AREAS COVERED

This article provides an overview of the treatment history of childhood leukemia and lymphoma as well as outlines the emerging late effects of treatments. We discuss the various types of these complications and their corresponding risk factors.

EXPERT OPINION

Standardizing survivorship care in pediatric cancer aims to improve patient well-being by optimizing their health outcomes and quality of life. This involves early identification and intervention of late effects, requiring collaboration among specialists, nurses, and advocates, and emphasizing data sharing and international cooperation.

How I treat long-term survivors of childhood acute leukemia

ABSTRACT

The population of survivors of childhood leukemia who reach adulthood is growing due to improved therapy. However, survivors are at risk of long-term complications. Comprehensive follow-up programs play a key role in childhood leukemia survivor care. The major determinant of long-term complications is the therapeutic burden accumulated over time. Relapse chemotherapy, central nervous system irradiation, hematopoietic stem cell transplantation, and total body irradiation are associated with greater risk of long-term complications. Other parameters include clinical characteristics such as age and sex as well as environmental, genetic, and socioeconomic factors, which can help stratify the risk of long-term complications and organize follow-up program. Early diagnosis improves the management of several late complications such as anthracycline-related cardiomyopathy, secondary cancers, metabolic syndrome, development defects, and infertility. Total body irradiation is the treatment associated with worse long-term toxicity profile with a wide range of complications. Patients treated with chemotherapy alone are at a lower risk of long-term complications, although the optimal long-term follow-up remains unclear. Novel immunotherapies and targeted therapy are generally associated with a better short-term safety profile but still require careful long-term toxicity monitoring. Advances in understanding genetic susceptibility to long-term complications could enable tailored therapeutic strategies for leukemia treatment and optimized follow-up programs.

Treatment and follow-up of children with chronic myeloid leukaemia in chronic phase (CML-CP) in the tyrosine kinase inhibitor (TKI) era-Two decades of experience from the Tata Memorial Hospital paediatric CML (pCML) cohort

Tyrosine kinase inhibitors (TKIs) have drastically improved the outcomes of pCML (paediatric CML) but data on long-term off-target toxicities of TKIs in children are scarce. In this single-centre, retrospective cum prospective study of pCML in chronic phase, we report our experience of treating 173 children with imatinib and following them for long-term toxicities. Mean (SD) time to attain CHR, CCyR and MMR were 3.05 (2.1), 10.6 (8.4) and 43.4 (31.8) months respectively. DMR was not attained in 59 (34%) patients at last follow-up. Ten patients were switched to second-generation TKIs (2G-TKIs; nilotinib = 1/dasatinib = 9) due to poor/loss in response, of which seven had kinase domain mutations. Three patients progressed to the blastic phase. At a median follow-up of 84 (3-261) months, the 5-year EFS and OS for the entire cohort were 96.9% (95% CI: 93.4-100) and 98.7% (95% CI: 96.9-100) respectively. Screening for long-term toxicities revealed low bone density and hypovitaminosis D in 70% and 80% respectively. Other late effects included short stature (27%), delayed puberty (15%), poor sperm quality (43%) and miscellaneous endocrinopathies (8%). Children younger than 5 years at diagnosis were more susceptible to growth and endocrine toxicities (p = 0.009). Regular monitoring for long-term toxicities, timely intervention and trial of discontinuation whenever feasible are likely to improve the long-term outlook of pCML.

Impact of Childhood Cancer on Growth

Along with improvements in cancer treatment over time, the number of childhood cancer survivors has been growing. Survivors are at risk for serious medical complications, and growth impairment is among the most common. There are multiple factors that may cause impaired growth among survivors. In this article, we review the impact of cancer on growth in children and adolescents. We first provide an overview of growth disturbance among childhood cancer patients and survivors due to nonhormonal causes, including a recent understanding of the effect of targeted cancer therapies (eg, tyrosine kinase inhibitors and immune checkpoint inhibitors) on growth. Then we describe the hormonal causes of growth impairment among survivors, focusing on growth hormone deficiency, including the prevalence, risk factors, and treatment. Lastly, we briefly summarize overgrowth and tall stature in childhood cancer. It is critical to assess the linear growth of children and adolescents, especially in cancer survivors who are at risk for growth disturbance, since growth is an important measure of their health.

Male Fertility and Fatherhood in Chronic Myeloid Leukemia: Current Understanding and Future Perspectives

Chronic myeloid leukemia (CML), while traditionally a disease of the elderly, has recently risen in incidence among younger patients. Hence, fertility concerns have emerged considering the disease process and treatments, especially with the current scarce and conflicting recommendations. This review explores the impact of CML treatments including the first-line tyrosine kinase inhibitors (TKIs) and other treatments on male fertility in chronic myeloid leukemia (CML) patients. The aim of this review was to compile the available evidence on male fertility to ultimately tailor treatment plans for male CML patients for whom fertility and future chances for conception pose a concern. The data available on the conventional and newer TKIs to address fertility concerns were reviewed, particularly the potential long- and short-term effects. Also, the possible side effects on subsequent generations were a crucial focus point of this review to reach a more comprehensive CML management approach. We found and compared the evidence on TKIs approved to treat CML. We also reported the effects of hydroxyurea, interferon, and transplantation, which are considered second-line treatments. Our findings suggest that these drugs might have an undiscovered effect on fertility. More research with larger sample sizes and longer follow-up periods is essential to solidify our understanding of these effects.

Philadelphia Chromosome Positive and Philadelphia-Like Acute Lymphoblastic Leukemia in Children and Adolescents: Current Management, Controversies and Emerging Concepts

Philadelphia chromosome positive (Ph+) acute lymphoblastic lymphoma (ALL) is an uncommon subtype of ALL in children, seen in 2-5% cases. Diagnostic evaluation includes conventional karyotyping and detection of BCR-ABL1 translocation by fluorescence in-situ hybridization (FISH) or reverse transcriptase polymerase chain reaction (RT-PCR). For children, the frontline management includes combination of intensive chemotherapy along with imatinib (300-340 mg/m2/d) or dasatinib (60-80 mg/m2/d). Imatinib/dasatinib should be introduced in induction as soon as results for BCR-ABL are available. Minimal residual disease (MRD) monitoring is essential; multi-parametric flowcytometry and immunoglobulin/T-cell receptor rearrangement PCR are the preferred methods. Intrathecal therapy with at least 12 doses of methotrexate is adequate for central nervous system (CNS) prophylaxis, but cranial radiation is necessary for CNS3 involvement. Allogeneic hematopoietic stem cell transplantation (HSCT) in first remission may be considered in high-risk cases (persistent MRD positivity/induction failure). Maintenance therapy with tyrosine kinase inhibitors (TKI) in children is debatable, with potential concerns for long term adverse effects. At relapse, the choice of TKI is guided by the presence of BCR-ABL tyrosine kinase domain resistance mutations, although the frequency of resistance mutations in children are lower. Allogeneic HSCT is essential for consolidation in second remission, if not done. Ph-like ALL is a newly recognized molecular entity, with gene expression profile similar to Ph+ALL and poor survival outcomes. In resource-constrained settings, a stepwise cost-effective diagnostic evaluation should be considered among high-risk patients without recurrent genetic abnormalities. Current treatment strategies remain similar to Ph-negative ALL. Enrolment in clinical trials is encouraged for such children to evaluate potential targeted agents in this subtype.

The long-term efficacy and safety of nilotinib in pediatric patients with CML: a 5-year update of the DIALOG study

The efficacy and safety of nilotinib in pediatric patients with imatinib/dasatinib resistant/intolerant (R/I) or newly diagnosed (ND) Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia in chronic phase (CML-CP) was demonstrated in the phase 2, open-label DIALOG study. In this final analysis, long-term efficacy and safety are presented for patients who completed 66 cycles (of 28 days) of treatment with nilotinib (230 mg/m2 twice daily) or discontinued early. Overall, 59 patients were enrolled and 58 were treated (R/I, n = 33; ND, n = 25; median time on treatment: 60.5 and 51.9 months, respectively). In the R/I cohort, the cumulative major molecular response (MMR; BCR::ABL1 international scale [IS] ≤ 0.1%) rate was 60.6%, and no patients had a confirmed loss of MMR. Among ND patients, the best overall MMR rate was 76.0%; 3 patients had a confirmed loss of MMR. The cumulative molecular response MR4 (BCR::ABL1IS ≤ 0.01%) and MR4.5 (BCR::ABL1IS ≤ 0.0032%) rates by 66 cycles were 27.3% and 12.1% in the R/I cohort, and 56.0% and 44.0% in the ND cohort, respectively. The safety profile of nilotinib was consistent with those of earlier reports. No on-treatment deaths occurred. These long-term (up to ∼5 years) data support the efficacy and safety of nilotinib in pediatric patients with Ph+ CML-CP. This trial was registered at www.clinicaltrials.gov.uk as #NCT01844765.

Effect of the tyrosine kinase inhibitors on the growth in children with Philadelphia chromosome-positive acute lymphoblastic leukemia: a case-control study

Background

First-generation ABL-targeted tyrosine kinase inhibitor (TKI) imatinib is known to retard growth in children but it is not known if the second-generation ABL-targeted TKI dasatinib has the same effect. We aimed to determine the impact of the first- or second-generation TKI on the growth of children treated for Philadelphia chromosome-positive (Ph+) childhood acute lymphoblastic leukemia (ALL).

Methods

We evaluated the longitudinal growth changes in 140 children with Ph+ ALL treated with imatinib or dasatinib in additional to intensive cytotoxic chemotherapy and 280 matched controls treated with the same intensity of cytotoxic chemotherapy without TKI on Chinese Children's Cancer Group ALL-2015 protocol between 2015 and 2019. We retrospectively reviewed the height data obtained during routine clinic visits at 4 time points: at diagnosis, the end of therapy, 1 year and 2 years off therapy. Height z Scores were derived with the aid of WHO Anthro version 3.2.2 and WHO AnthroPlus version 1.0.4, global growth monitoring tool.

Findings

This study consisted only patients who have completed all treatment in continuous complete remission without major events, including 33 patients randomized to receive imatinib, 43 randomized to receive dasatinib, and 64 assigned to receive dasatinib. Similar degree of loss of height z scores from diagnosis to the end of therapy was observed for the 33 imatinib- and the 107 dasatinib-treated patients (median △ = -0.84 vs. -0.88, P = 0.41). Adjusting for height z score at diagnosis, puberty status, and sex, there was no significant difference in the longitudinal mean height z scores between patients treated with imatinib and those with dasatinib (0.08, 95% CI, -0.22 to 0.38, P = 0.60). The degree of loss of height z scores from diagnosis to end of therapy was significantly greater in the 140 TKI-treated patients than the 280 controls (median △ = -0.88 vs. -0.18, P < 0.001). The longitudinal mean height z scores in the TKI-treated patients were significantly lower than those of the controls (-0.84, 95% CI, -0.98 to -0.69; P < 0.001).

Interpretation

These data suggest that dasatinib and imatinib have the similar adverse impact on the growth of children with Ph+ ALL.

Funding

This study was supported by the National Natural Science Foundation of China (grant 81670136 [JCai and JT]), the fourth round of Three-Year Public Health Action Plan (2015-2017; GWIV-25 [SS]), Shanghai Health Commission Clinical Research Project (202140161 [JCai]), the US National Cancer institute (CA21765 [C-H Pui]), and the American Lebanese Syrian Associated Charities (CC, JJY, and C-HP). The content of this paper is solely the responsibility of the authors and does not necessarily represent the official views of the US National Institutes of Health.

Effect of Imatinib Mesylate on Growth in Pediatric Chronic Myeloid Leukemia: A Systematic Review and Meta-analysis

The outcomes of pediatric chronic myeloid leukemia (CML) have improved with the use of imatinib mesylate (IM). Multiple reports of growth deceleration with IM have raised concerns, necessitating careful monitoring and evaluation in children with CML. We systematically searched the databases of PubMed, EMBASE, Scopus, CENTRAL, and conferences-abstracts, reporting the effect of IM on growth among children with CML, and published in the English language from inception till March 2022. For observational studies, the modified Newcastle Ottawa Scale was used to assess the risk of bias. Pooled estimates were derived using a random-effects meta-analysis, and heterogeneity was assessed using Cochrane Q statistic test of heterogeneity and I2 statistic. Of the 757 studies identified through electronic search, 15 (n=265) were included in the final analysis. Six studies (n=178) were included in the meta-analysis of the primary outcome. There was a significant deleterious effect of IM on height-standardized mean difference (SMD): -0.52 (95% CI: -0.76; -0.28) ( I2 =13%). The adverse effect of IM on height was significant among studies with a follow-up period <3 years [SMD: -0.66 (95% CI: -0.93, -0.40), I2 =0%, P =0.59] but not in studies with follow-up period ≥3 years [SMD: -0.26 (95% CI: -0.63, 0.11), I2 =0, P =0.44], indicating that the effect of IM on height is a short-term effect. The effect of IM on height was not dependent upon pubertal status at the initiation of therapy. Prospective studies with adequate sample size are required to confirm the findings of the effect of IM on height in children with CML.

Pediatric Autologous Hematopoietic Stem Cell Transplantation: Safety, Efficacy, and Patient Outcomes. Literature Review

Autologous stem cell transplantation (auto-HSCT) is a part of the therapeutic strategy for various oncohematological diseases. The auto-HSCT procedure enables hematological recovery after high-dose chemotherapy, otherwise not tolerable, by the infusion of autologous hematopoietic stem cells. Unlike allogeneic transplant (allo-HSCT), auto-HSCT has the advantage of lacking acute-graft-versus-host disease (GVHD) and prolonged immunosuppression, however, these advantages are counterbalanced by the absence of graft-versus-leukemia. Moreover, in hematological malignancies, the autologous hematopoietic stem cell source may be contaminated by neoplastic cells, leading to disease reappearance. In recent years, allogeneic transplant-related mortality (TRM) has progressively decreased, almost approaching auto-TRM, and many alternative donor sources are available for the majority of patients eligible for transplant procedures. In adults, the role of auto-HSCT compared to conventional chemotherapy (CT) in hematological malignancies has been well defined in many extended randomized trials; however, such trials are lacking in pediatric cohorts. Therefore, the role of auto-HSCT in pediatric oncohematology is limited, in both first- and second-line therapies and still remains to be defined. Nowadays, the accurate stratification in risk groups, according to the biological characteristics of the tumors and therapy response, and the introduction of new biological therapies, have to be taken into account in order to assign auto-HSCT a precise role in the therapeutic strategies, also considering that in the developmental age, auto-HSCT has a clear advantage over allo-HSCT, in terms of late sequelae, such as organ damage and second neoplasms. The purpose of this review is to report the results obtained with auto-HSCT in the different pediatric oncohematological diseases, focusing on the most significant literature data in the context of the various diseases and discussing this data in the light of the current therapeutic landscape.

Recent progress in the management of pediatric chronic myeloid leukemia

Chronic myeloid leukemia (CML) is a rare myeloproliferative disease in children. The primary cause of CML is the chimeric BCR::ABL1 gene in hematopoietic stem cells, which leads to leukocytosis, platelet proliferation, and splenomegaly. Lately, tyrosine kinase inhibitors (TKIs) have replaced hematopoietic cell transplantation, which was previously considered the only curative therapy, as the first-line treatment for chronic-phase CML. However, the clinical efficacy of TKIs, including those effective in adult CML, has not been well-investigated in pediatric CML. This review describes the recommended TKI-based management strategies for pediatric CML according to the literature and guidelines. Furthermore, we discuss the prospects for TKI discontinuation to avoid important adverse events, such as growth impairment, in children.

Guest editorial: recent progress in pediatric leukemia

Recent progress in comprehensive genomic analysis and well-designed clinical trials has dramatically improved the treatment strategies for pediatric leukemia, resulting in better prognosis and reducing acute and late adverse events. This review series describes successes and challenges for the future in the management of pediatric leukemia.

Modulation of 25(OH) vitamin D3 level by Imatinib mesylate in patients with chronic myelogenous leukaemia: The role of uptake and efflux transporters

Background

Objective

Methods

Results

Conclusions

Distribution and frequency of tyrosine kinase inhibitor-associated long-term complications in children with chronic myeloid leukemia

BACKGROUND

Tyrosine kinase inhibitors (TKIs) improve outcomes for pediatric malignancies characterized by specific gene rearrangements and mutations; however, little is known about the long-term impact of TKI exposure. Our objective was to assess the incidence and type of late-onset TKI-related toxicities in children with chronic myeloid leukemia (CML).

METHODS

We reviewed medical records from patients diagnosed with CML between 2006 and 2019 at <21 years of age and prescribed one or more TKIs. Patients treated with stem cell transplant were excluded. Outcomes were captured beginning at 1 year after CML diagnosis. Outcome incidence was described overall and stratified by TKI exposure during the data-capture period.

RESULTS

Twenty-two eligible TKI-exposed patients with CML were identified. The median follow-up was 6.0 years (range: 2.2-14.3). All pericardial (n = 3) or pleural (n = 3) effusion outcomes occurred in patients treated with TKIs during the data-capture period. Other outcomes included hypertension (n = 2), ectopy on electrocardiogram (n = 2), and gastrointestinal bleed (n = 1). All outcomes were graded as mild to moderate: some resulted in a temporary discontinuation of TKI, but none led to a change in TKI. No differences were noted in outcome incidence by type of TKI exposure.

CONCLUSIONS

TKIs have substantially improved prognosis for subsets of childhood leukemia, but there are limited long-term data to inform exposure-based risk for late-onset complications and screening. Our results suggest that TKI-exposed survivors may be at risk for long-term outcomes that extend well into survivorship.

Discontinuation of tyrosine kinase inhibitors in pediatric chronic myeloid leukemia

BACKGROUND

The feasibility of tyrosine kinase inhibitor (TKI) discontinuation in pediatric chronic myeloid leukemia (CML) remains to be fully elucidated.

PROCEDURES

TKI was prospectively discontinued in patients who were diagnosed with CML at <20 years of age, treated with TKI for ≥3 years, and sustained molecular response 4.0 (MR4.0) for ≥2 years. Molecular relapse was defined as a single loss of major molecular response (MMR) (BCR-ABL1^IS >0.1%). Relapsed patients resumed the same TKI therapy administered before discontinuation.

RESULTS

Twenty-two patients with chronic-phase CML were enrolled, and the median ages at diagnosis and at TKI discontinuation were 9 (range: 1-14) years and 16 (5-26) years, respectively. The median follow-up time after TKI discontinuation was 37 months (range: 24-41 months). The median duration of TKI treatment before discontinuation was 100 (42-178) months, and that of MR4.0 was 53.5 (25-148) months. The treatment-free remission (TFR) rate at 12 months was 50.0% (90% confidence interval: 31.7%-65.8%). Eleven patients experienced loss of MMR within 4 months after TKI discontinuation and resumed TKI as originally prescribed. No progression was observed, and all 11 patients regained MR4.0 after TKI resumption. No patient had a withdrawal syndrome. The quality-of-life analysis suggested that successful TFR may improve academic performance in some patients. In patients who discontinued TKI therapy before puberty, the possibility of improvement in growth velocity upon TKI discontinuation was observed.

CONCLUSIONS

TKI could be discontinued safely in patients with pediatric CML showing a sustained deep MR.

Prognostic Factors for Outcomes of Allogeneic HSCT for Children and Adolescents/Young Adults with CML in the TKI Era

BACKGROUND

The breakthrough effects of tyrosine kinase inhibitors (TKIs) have lessened indications for allogeneic hematopoietic stem cell transplantation (HSCT) in chronic myeloid leukemia (CML). However, HSCT is still attractive for children and adolescents/young adults (AYAs) requiring lifelong TKI therapy. Nevertheless, little has been reported on the outcomes of large clinical studies of HSCT targeting these age groups.

OBJECTIVE

This study aimed to identify prognostic factors for the outcomes of HSCT, including reduced-intensity conditioning (RIC)-HSCT, for children and AYAs with CML in the TKI era.

STUDY DESIGN

We performed a registry analysis for 200 patients with CML aged <30 years who underwent pretransplant TKI therapy from the observational nationwide database established by the Japanese Society for Transplantation and Cellular Therapy. The patients received bone marrow (BM), peripheral blood (PB), or cord blood (CB) from either related or unrelated donors. The indication for HSCT for individual patients was determined by the institution according to European LeukemiaNet recommendations and other guidelines.

RESULTS

The 5-year overall survival (OS) rates for patients with chronic phase (CP) (n = 124), accelerated phase (AP) (n = 23), and blastic phase (BP) (n = 53) at diagnosis were 82.8%, 71.1%, and 73.3%, respectively, with no significant difference (P = 0.3293). The strongest predictor of engraftment was transplant source, with CB (hazard ratio [HR], 0.33) and PB (HR, 2.00) (compared with BM) being independent unfavorable and favorable predictors, respectively. Transplant source was also an independent predictor of chronic GVHD, with PB (HR, 1.81) and CB (HR, 0.39) (compared with BM) being unfavorable and favorable predictors, respectively. The strongest predictor of OS rate for patients with CP at diagnosis was disease phase at HSCT, with second or greater CP, AP, or BP (HR, 2.81) (compared with first CP [CP1]) being an unfavorable predictor. In addition, patients with CP at diagnosis who had major and complete molecular responses at HSCT had excellent outcomes, with 5-year OS rates of 100% and 94.4%, respectively. The 5-year OS rate was compared between RIC (n = 31) and myeloablative conditioning (MAC) (n = 58) in patients with CP1, both of which were 89.3%, with no significant difference (P = 0.9440). On univariate analysis for the RIC cohort with CP at diagnosis, the age at HSCT (HR, 1.27) (increase per year) and the time from diagnosis to HSCT (HR, 1.83) (increase per year) were significant predictors for OS.

CONCLUSIONS

Our study demonstrates that RIC may be an appropriate alternative to MAC for children and AYAs with CP1. As for the transplant source, we recommend first selecting BM because of a higher engraftment rate compared to CB and a lower incidence of chronic GVHD compared to PB. Although HSCT in the status of a major molecular response is desirable, it is not advisable to continue TKI pointlessly long because age at HSCT and timing of HSCT are prognostic factors that determine survival. The decision to perform RIC-HSCT instead of continuing TKI should be carefully made, considering the possibility of transplant-related complications.

A phase 2 study of nilotinib in pediatric patients with CML: long-term update on growth retardation and safety

The phase 2, open-label study (DIALOG) of nilotinib in pediatric patients with Philadelphia chromosome-positive chronic myelogenous leukemia (CML) met its coprimary end points, showing sustained nilotinib efficacy in patients with newly diagnosed (ND) or imatinib/dasatinib resistant/intolerant (R/I) CML. This update assessed growth and safety profiles in patients who had completed ≥48, 28-day treatment cycles of nilotinib 230 mg/m2 twice daily, or previously discontinued the study. Height was assessed regularly and reported using standard deviation scores (SDSs) based on World Health Organization growth charts. All data were summarized descriptively (cutoff, 6 March 2019). Overall, 33 patients in the R/I cohort and 25 patients in the ND cohort received nilotinib. Each cohort showed a negative slope in height SDS over the course of the study, indicating attenuated growth rates during nilotinib treatment: overall median change from baseline in height SDS after 48 cycles was -0.54 SDS (range, - 1.6 to 0.4) and -0.91 SDS (-1.4 to -0.1) in R/I and ND cohorts, respectively. Patients in the R/I cohort were shorter at baseline than those in the ND cohort, and remained so throughout the study. The most common all-cause adverse events were increased blood bilirubin (53.4%), headache (46.6%), pyrexia (37.9%), and increased alanine transferase (36.2%). Apart from the impact on growth, the safety profile of nilotinib was generally consistent with previous reports. This study was registered on www.clinicaltrials.gov at #NCT01844765.

Treatment-Free Remission-A New Aim in the Treatment of Chronic Myeloid Leukemia

Tyrosine kinases inhibitors (TKIs) revolutionized chronic myeloid leukemia (CML) treatment for many years, prolonging patients' life expectancy to be comparable to age-matched healthy individuals. According to the latest the European LeukemiaNet (ELN) recommendations, CML treatment aims to achieve long-term remission without treatment (TFR), which is feasible in more than 40% of patients. Nearly all molecular relapses occur during the first 6 months after TKI withdrawal and do not progress to clinical relapse. The mechanisms that are responsible for CML relapses remain unexplained. It is suggested that maintaining TFR is not directly related to the total disposing of the gene transcript BCR-ABL1, but it might be a result of the restoration of the immune surveillance in CML. The importance of the involvement of immunocompetent cells in the period of TKI withdrawal is also emphasized by the presence of specific symptoms in some patients with "withdrawal syndrome". The goal of this review is to analyze data from studies regarding TFRs in order to characterize the elements of the immune system of patients that might prevent CML molecular relapse. The role of modern droplet digital polymerase chain reaction (ddPCR) and next-generation sequencing (NGS) in better identification of low levels of BCR-ABL1 transcripts was also taken into consideration for refining the eligibility criteria to stop TKI therapy.

Adolescents experienced more treatment failure than children with chronic myeloid leukemia receiving imatinib as frontline therapy: a retrospective multicenter study

To explore the differences in the clinical features, treatment responses, and outcomes among children, adolescents, and adults with chronic myeloid leukemia in the chronic phase (CML-CP) receiving imatinib as first-line therapy. Data from children (0-8 years for girls and 0-10 years for boys), adolescents (9-19 years for girls and 11-19 years for boys), and adults (age ≥ 20 years) with newly diagnosed CML-CP receiving imatinib as first-line therapy between 2006 and 2019 were retrospectively reviewed. In total, 135 children (cohort 1), 189 adolescents (cohort 2), and 658 adults (cohort 3: age 20-39 years, n = 305; cohort 4: age 40-59 years, n = 270; and cohort 5: age 60-83 years, n = 83) were included in this study. When compared with children, adolescents showed a significantly higher white blood cell count (P = 0.033) and basophil percentage in peripheral blood (P = 0.002) and a significantly higher prevalence of splenomegaly (P = 0.004). Both children and adolescents presented with more aggressive clinical features than adults. During median follow-ups of 28 months (range, 3-161 months) in children, 33 months (range, 3-152 months) in adolescents, and 48 months (range, 3-157 months) in adults, multivariate analysis showed that children and adolescents had higher probabilities of achieving complete cytogenetic response, major molecular response, and molecular response^4.5. Notably, compared with not only adults (cohort 3 vs. cohort 1: HR = 2.03 [1.03, 3.98], P = 0.040; cohort 4 vs. cohort 1: HR = 2.15 [1.07, 4.33], P = 0.033; cohort 5 vs. cohort 1: HR = 4.22 [1.94, 9.15], P < 0.001) but also adolescents (cohort 2 vs. cohort 1: HR = 2.36 [1.18, 4.72], P = 0.015), children had significantly longer failure-free survival. Age was not associated with progression-free survival or overall survival. Although they exhibited more aggressive clinical features at diagnosis, both children and adolescents achieved superior treatment responses than adults. Adolescents showed even more adverse features and a poor FFS than children.

Patterns of surveillance for late effects of BCR-ABL tyrosine kinase inhibitors in survivors of pediatric Philadelphia chromosome positive leukemias

BACKGROUND

Targeted anticancer therapies such as BCR-ABL tyrosine kinase inhibitors (TKIs) have improved outcomes for chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL). However, little is known about long-term risks of TKIs in children. Exposure-based survivorship guidelines do not include TKIs, thus surveillance practices may be variable.

METHODS

We retrospectively examined surveillance for cardiac and endocrine late effects in children receiving TKIs for Ph + leukemias, diagnosed at < 21 years between 2000 and 2018. Frequency of echocardiogram (ECHO), electrocardiogram (EKG), thyroid stimulating hormone (TSH), dual-energy x-ray absorptiometry (DXA), and bone age testing were abstracted. Descriptive statistics were stratified by leukemia type.

RESULTS

66 patients (CML n = 44; Ph + ALL n = 22) met inclusion criteria. Among patients with CML, ≥1 evaluation was done: ECHO (50.0%), EKG (48.8%), TSH (43.9%), DXA (2.6%), bone age (7.4%). Among patients with Ph + ALL, ≥1 evaluation was done: ECHO (86.4%), EKG (68.2%), TSH (59.1%), DXA (63.6%), bone age (44.4%). Over a median 6.3 and 5.7 years of observation, respectively, 2% of patients with CML and 57% with Ph + ALL attended a survivorship clinic.

CONCLUSIONS

Despite common exposure to TKIs in survivors of Ph + leukemias, patterns of surveillance for late effects differed in CML and Ph + ALL, with the latter receiving more surveillance likely due to concomitant chemotherapy exposures. Targeted therapies such as TKIs are revolutionizing cancer treatment, but surveillance for late effects and referral to survivorship clinics are variable despite the chronicity of exposure. Evidence based guidelines and longer follow-up are needed.

Opportunities and Challenges in Drug Development for Pediatric Cancers

The use of targeted small-molecule therapeutics and immunotherapeutics has been limited to date in pediatric oncology. Recently, the number of pediatric approvals has risen, and regulatory initiatives in the United States and Europe have aimed to increase the study of novel anticancer therapies in children. Challenges of drug development in children include the rarity of individual cancer diagnoses and the high prevalence of difficult-to-drug targets, including transcription factors and epigenetic regulators. Ongoing pediatric adaptation of biomarker-driven trial designs and further exploration of agents targeting non-kinase drivers constitute high-priority objectives for future pediatric oncology drug development. SIGNIFICANCE: Increasing attention to drug development for children with cancer by regulators and pharmaceutical companies holds the promise of accelerating the availability of new therapies for children with cancer, potentially improving survival and decreasing the acute and chronic toxicities of therapy. However, unique approaches are necessary to study novel therapies in children that take into account low patient numbers, the pediatric cancer genomic landscape and tumor microenvironment, and the need for pediatric formulations. It is also critical to evaluate the potential for unique toxicities in growing hosts without affecting the pace of discovery for children with these life-threatening diseases.

Features and outcome of chronic myeloid leukemia at very young age: Data from the International Pediatric Chronic Myeloid Leukemia Registry

INTRODUCTION

Chronic myeloid leukemia (CML) is rare in the first two decades of life comprising only 3% of newly diagnosed pediatric and adolescent leukemias. We studied the epidemiologic and clinical features of patients with CML diagnosed at younger than 3 years of age and evaluated treatment and long-term outcome.

METHOD

Data from the International Pediatric I-BFM/CML Registry were retrospectively analyzed using the European LeukemiaNet criteria of the year 2006. Characteristics and treatment outcome of patients <3 years old at diagnosis were evaluated from standardized forms.

RESULTS

Twenty-two patients (n = 22/479; 4.6%, male/female:14/8) were enrolled with a median age of 22 months (range, 10-34 m). Major symptoms comprised asthenia (30%), fever (30%), abdominal pain (20%), extramedullary signs (14%), hemorrhage (5%), and weight loss (5%). The extramedullary signs were specified in eight children: blueberry muffin (n = 1), sudden swollen abdomen (n = 1), sustained vomiting (n = 1), and cervical and inguinal lymph nodes (n = 5). Two of five children with cervical and inguinal lymph nodes were categorized as accelerated phase. Overall, 19 of 22 (86%) children were diagnosed in chronic phase, while the remaining three patients were in advanced phase. Median follow-up was 78 months (range, 7-196 m). Twenty-one out of 22 patients initially received imatinib, while one child received IFN + ARA-C. Imatinib was changed to second-line tyrosine kinase inhibitors (TKIs) in 29% of cases. During follow-up, 41% patients underwent stem cell transplantation (SCT). While on TKI, major molecular response (MMR) was achieved in 48% of children. Among the remaining patients, 21% are alive on TKI without MMR and 22% achieved complete molecular response following SCT. Twenty-one of 22 (95%) children are alive, while one patient died of posttransplant complications.

CONCLUSION

This report demonstrates for the first time the efficacy and long-term effects of upfront imatinib in the so far largest cohort of children with CML diagnosed at very young age.

Long-term safety and efficacy of imatinib in pediatric patients with chronic myeloid leukemia: single-center experience from China

Chronic myeloid leukemia (CML) is a rare disease among children. A retrospective study was conducted from November 2002 to March 2019 at a single institution in China. A total of 36 pediatric CML patients (25 male and 11 female) were enrolled. Median follow-up time was 51 months (range 8-144), and 5-year overall survival and event-free survival were 95.5 ± 4.4% and 88.9 ± 6.0%, respectively. Among the 25 patients whose response to imatinib mesylate (IM) was regularly monitored, 92.0% achieved complete hematologic response at 3 months, 80.0% achieved complete cytogenetic response at 12 months, and 64.0% achieved major molecular response at 18 months after IM therapy. A higher WBC count at diagnosis was associated with failure to achieve early molecular response (EMR). Height standard deviation score after long-term treatment was significantly and positively correlated with age at diagnosis and at the start of IM therapy. Overall, IM therapy was effective in treating pediatric CML, and WBC count at diagnosis might be an ideal predictor of EMR. Moreover, retardation of height and weight growth due to IM tended to affect patients younger than 9 years old at diagnosis, and longitudinal growth might normalize further into treatment.

Endocrine Health in Childhood Cancer Survivors

Endocrine late effects, including reproductive disorders and secondary thyroid cancer, have been reported in up to 50 %childhood cancer survivors (CCS) more than 5 years after treatment. Most endocrine disorders are amenable to treatment; awareness of symptoms is therefore of great importance. Recognition of these symptoms may be delayed however because many are nonspecific. Timely treatment of endocrine disorders improves quality of life in CCS and prevents possible consequences, such as short stature, bone and cardiovascular disorders, and depression. At-risk CCS must therefore be regularly and systematically monitored. This article provides a summary of the most commonly reported endocrine late effects in CCS.

The Future of Childhood Cancer Survivorship: Challenges and Opportunities for Continued Progress

As treatment evolves and the population who survive childhood cancer ages and increases in number, researchers must use novel approaches to prevent, identify and mitigate adverse effects of treatment. Future priorities include collaborative efforts to pool large cohort data to improve detection of late effects, identify late effects of novel therapies, and determine the contribution of genetic factors along with physiologic and accelerated aging among survivors. This knowledge should translate to individual risk prediction and prevention strategies. Finally, we must utilize health services research and implementation science to improve adoption of survivorship care recommendations outside of specialized pediatric oncology centers.

[Effect of imatinib on the height of children with chronic myeloid leukemia in the chronic phase]

目的

评估伊马替尼对慢性髓性白血病慢性期（CML-CP）儿童身高的影响。

方法

2018年7月至2019年7月，在全国范围内对诊断时年龄<18周岁、接受伊马替尼治疗至少3个月的CML儿童或其家长发放问卷，调查受访者伊马替尼治疗前后身高的变化。主要评价指标为身高标准差积分值（HtSDS）以及标准差积分的差值（ΔHtSDS），并分析其相关影响因素。

结果

共有238例受访者符合标准并被纳入研究，男性138例（58.0％），初诊时中位年龄11.0（1.4～17.9）岁，青春期前93例（39.0％），至填写答卷时，中位年龄15.0（2.0～34.0）岁，中位伊马替尼服药时间28（3～213）个月。受访者填写答卷时HtSDS（−0.063±1.361）较治疗前HtSDS（0.391±1.244）显著下降（P<0.001），71.0％的患儿出现身高增长减慢。青春期前服药者治疗后HtSDS下降显著（P<0.05），而青春期开始后服药者HtSDS变化不明显（P>0.05）。多因素分析显示，服药初始年龄较小（偏回归系数为0.122，B＝0.572，t＝10.733，P<0.001）和服药时间较长（偏回归系数为−0.006，B＝−0.211，t＝−4.062，P<0.001）是伊马替尼抑制身高增长的独立影响因素。

结论

伊马替尼引起CML-CP儿童身高增长障碍，服药初始年龄越小、服药时间越长，伊马替尼对身高的影响越明显。

Sustained molecular response following a failed attempt of tyrosine kinase inhibitor discontinuation & the effects on growth in a child with chronic myeloid leukemia: not always a short story

We report a patient who developed chronic myelogenous leukemia (CML) at 12 months of age. She was treated aggressively with stem cell transplant (SCT), interferon, donor lymphocytes and imatinib, with subsequent molecular progression. She received dasatinib, achieving a complete molecular response. Dasatinib was discontinued at 3 years but she had a molecular recurrence. Dasatinib was restarted and continued for 5 additional years with a second major molecular remission (MMR). While on dasatinib therapy she suffered growth failure and was treated with concurrent growth hormone (GH). After discontinuing dasatinib and GH, catch-up growth continues and she remains in MMR. Discontinuation of TKI therapy and the toxicity of long-term TKI therapy is discussed.

Bcr-Abl Tyrosine Kinase Inhibitors in the Treatment of Pediatric CML

The therapeutic approach to Chronic Myeloid Leukemia (CML) has changed since the advent of the tyrosine kinase inhibitor (TKI) imatinib, which was then followed by the second generation TKIs dasatinib, nilotinib, and, finally, by ponatinib, a third-generation drug. At present, these therapeutic options represent the first-line treatment for adults. Based on clinical experience, imatinb, dasatinib, and nilotinib have been approved for children even though the studies that were concerned with efficacy and safety toward pediatric patients are still awaiting more specific and high-quality data. In this scenario, it is of utmost importance to prospectively validate data extrapolated from adult studies to set a standard therapeutic management for pediatric CML by employing appropriate formulations on the basis of pediatric clinical trials, which allow a careful monitoring of TKI-induced adverse effects especially in growing children exposed to long-term therapy.

Impact of tyrosine kinase inhibitors on the statural growth in children with acute lymphoblastic leukemia

PURPOSE

To investigate the effect of tyrosine kinase inhibitors (TKIs) on the statural growth in children with acute lymphoblastic leukemia (ALL).

METHODS

We retrospectively collected data from 344 children with ALL younger than 17 years old at diagnosis identified in pediatric department of Peking University People's Hospital. The children were divided into three groups: conventional chemotherapy group, imatinib group and dasatinib group. Height was expressed as standard deviation score(HtSDS). In the three groups, we compared the HtSDS and △HtSDS at the start of treatment and during follow-up period and also compared the adult height and median parental height(MPH). We further compared the HtSDS classified by age and gender in imatinib group. At last, univariate analysis was used to analyze the influencing factors on the deceleration of height growth by imatinib.

RESULTS

There were 298 children in conventional chemotherapy group, 39 in imatinib group and 7 in dasatinib group. In imatinib group, the mean HtSDS of children at follow-up time was significantly lower than that at the start of treatment (P < 0.05), regardless of age and gender. In imatinib group, the decrease of HtSDS in girls was more obvious than in boys(P = 0.031). The HtSDS gradually decreased in the first and the second year in imatinib group. After discontinuation of imatinib, the HtSDS had no obvious change. Multivariate analysis showed that the HtSDS at the start of imatinib was negatively correlated with severe growth impairment on imatinib therapy. The HtSDS in dasatinib group and conventional chemotherapy group maintained a high degree of consistency.

CONCLUSION

Imatinib can affect growth velocity in children with ALL, regardless of age and gender. With the discontinuation of imatinib, the inhibitory effect will not continue. The lower HtSDS at the start of imatinib therapy, the more obvious effect of imatinib on growth impairment will be, and the effect will be more obvious in girls than boys.

Chronic Myeloid Leukemia in Children: Challenges and Opportunities : Based on 7th Dr. I. C. Verma Excellence Award for Young Pediatricians Delivered as Oration on 29th Sept. 2019

Treatment with tyrosine kinase inhibitors (TKI) is an effective therapy for children and adolescents with chronic phase of chronic myeloid leukemia (CML). For the majority of patients with CML in low- and middle-income countries (LMIC), imatinib is the TKI of choice for reasons of cost, availability, and experience. Children are exposed to therapy for a greater proportion of their lifetime as compared to adults. The adverse effects of prolonged administration of TKI is a subject of ongoing research, as more experience is collected. Therapy with TKI is currently considered to be life-long. Trials on stopping treatment are ongoing to explore if it may be feasible in selected patients, as reported in adults. Growth-failure is a concerning adverse effect. Currently, it seems unclear if the final height attained is within the expected range of the mid-parenteral height and growth standards. Whether the children will achieve a normal height at the end of their growth potential or remain below the predicted range is critical to decide if therapeutic interventions (E.g., growth hormone therapy, or interruption in TKI) should be considered during the period of growth potential. Research on CML in children is at a relatively slow pace, largely due to the rarity of the disease. This provides a unique opportunity for research in population-dense LMICs, as several tertiary centers tend to have a sizable cohort of children and adolescents with CML on follow-up. This narrative summarises the challenges and opportunities in dealing with CML in children, particularly in reference to a center in LMIC.

Risk Factors for Small Adult Height in Childhood Cancer Survivors

PURPOSE

Between 10% and 20% of childhood cancer survivors (CCS) experience impaired growth, leading to small adult height (SAH). Our study aimed to quantify risk factors for SAH or growth hormone deficiency among CCS.

METHODS

The French CCS Study holds data on 7,670 cancer survivors treated before 2001. We analyzed self-administered questionnaire data from 2,965 CCS with clinical, chemo/radiotherapy data from medical records. SAH was defined as an adult height ≤ 2 standard deviation scores of control values obtained from a French population health study.

RESULTS

After exclusion of 189 CCS treated with growth hormone, 9.2% (254 of 2,776) had a SAH. Being young at the time of cancer treatment (relative risk [RR], 0.91 [95% CI, 0.88 to 0.95] by year of age), small height at diagnosis (≤ 2 standard deviation scores; RR, 6.74 [95% CI, 4.61 to 9.86]), pituitary irradiation (5-20 Gy: RR, 4.24 [95% CI, 1.98 to 9.06]; 20-40 Gy: RR, 10.16 [95% CI, 5.18 to 19.94]; and ≥ 40 Gy: RR, 19.48 [95% CI, 8.73 to 43.48]), having received busulfan (RR, 4.53 [95% CI, 2.10 to 9.77]), or > 300 mg/m² of lomustine (300-600 mg/m²: RR, 4.21 [95% CI, 1.61 to 11.01] and ≥ 600 mg/m²: RR, 9.12 [95% CI, 2.75 to 30.24]) were all independent risk factors for SAH. Irradiation of ≥ 7 vertebrae (≥ 15 Gy on ≥ 90% of their volume) without pituitary irradiation increased the RR of SAH by 4.62 (95% CI, 2.77 to 7.72). If patients had also received pituitary irradiation, this increased the RR by an additional factor of 1.3 to 2.4.

CONCLUSION

CCS are at a high risk of SAH. CCS treated with radiotherapy, busulfan, or lomustine should be closely monitored for growth, puberty onset, and potential pituitary deficiency.

Phase 2 study of nilotinib in pediatric patients with Philadelphia chromosome-positive chronic myeloid leukemia

Chronic myeloid leukemia (CML) is rare in children and accounts for ≤15% of all myeloid leukemia cases. When we initiated this study with nilotinib, imatinib was the only tyrosine kinase inhibitor indicated for pediatric patients with Philadelphia chromosome-positive (Ph+) CML in chronic phase (CP); alternative treatment options were needed, particularly for patients who developed resistance or intolerance (R/I) to imatinib. This phase 2 study enrolled pediatric patients with either Ph+ CML-CP R/I to imatinib or dasatinib or newly diagnosed Ph+ CML-CP. Data presented are from analyses with minimum follow-up of up to 24 cycles (1 cycle is 28 days). Fifty-nine patients with Ph+ CML-CP were enrolled, and 58 were treated (R/I, n = 33; newly diagnosed, n = 25). Major molecular response (MMR) rate at cycle 6 in the R/I cohort was 39.4% (primary end point); 57.6% of patients achieved or maintained MMR and 81.8% achieved or maintained complete cytogenetic response (CCyR) by 24 cycles. In patients with newly diagnosed disease, rates of MMR by cycle 12 and CCyR at cycle 12 were 64.0% each (primary end points); by cycle 24, cumulative MMR and CCyR rates were 68.0% and 84.0%, respectively. The safety profile of nilotinib in pediatric patients was generally comparable with the known safety profile in adults, although cardiovascular events were not observed in this study, and hepatic laboratory abnormalities were more frequent; no new safety signals were identified. In summary, nilotinib demonstrated efficacy and a manageable safety profile in pediatric patients with Ph+ CML-CP. This trial was registered at www.clinicaltrials.gov as #NCT01844765.

Acquired neuro-secretory defect in growth hormone secretion due to Imatinib mesylate and the efficacy of growth hormone therapy in children with chronic myeloid leukemia

Imatinib results in growth retardation in children with chronic myeloid leukemia (CML). The study was planned to assess the GHRH-GH-IGF1 axis in children with CML, receiving Imatinib and to evaluate the efficacy of human growth hormone (hGH) therapy. Twenty children with CML, receiving Imatinib for a period exceeding 6 months, with resultant growth retardation were included. The GHRH-GH-IGF1 axis was assessed using growth hormone stimulation tests. IGF-1 generation test was performed for the evaluation of GH insensitivity. The mean age at inclusion was 15.2 years. The mean duration of treatment with Imatinib was 5.7 years. The mean decrease in height SDS since the start of Imatinib was -0.95 (p = 0.008). IGF-1 SDS was <-2 in all the patients. 71.4% of patients had a suboptimal GH response following stimulation with GHRH-Arginine. All patients had stimulable, although a delayed GH response with glucagon stimulation. 20% of patients had GH insensitivity. Four patients were treated with hGH for a mean duration of 5.75 months, achieved normalization of IGF-1 levels and improvement in growth velocity improved from 0.21 to 0.86 cm/month. Imatinib results in an acquired neurosecretory defect in GH secretion. Treatment with growth hormone leads to an improvement in growth velocity and normalization of IGF-1.

Current and coming challenges in the management of the survivorship population

With the widespread adoption of multimodality treatment, 5-year survival of children diagnosed with cancer has improved dramatically in the past several decades from approximately 60% in 1970 to greater than 85% currently. As a result, there are an estimated nearly half a million long-term survivors of childhood cancer living in the United States today. However, survivors have, on average, significantly greater serious medical and psychosocial late effects compared with the general population. In this review, we will discuss the current epidemiology of childhood cancer survivorship, including new methods to estimate the burden of late effects and genetic susceptibility toward late effects. We will also review the development of surveillance guidelines for childhood cancer survivors and early toxicity signals from novel agents now being tested and used increasingly to treat pediatric and adult cancers. We conclude with an overview of current models of survivorship care and areas for future research.

[Influence of dasatinib treatment on body height in children with acute myeloid leukemia]

OBJECTIVE

To study the influence of dasatinib treatment on body height in children with acute myeloid leukemia (AML).

METHODS

A retrospective analysis was performed for the clinical data of 86 AML children aged <17 years. According to the treatment regimen, these children were divided into a conventional chemotherapy group and a dasatinib chemotherapy group. The 57 children in the conventional chemotherapy group were given conventional chemotherapy drugs without tyrosine kinase inhibitor, and the 29 children in the dasatinib chemotherapy group were given conventional chemotherapy drugs and dasatinib. The two groups were compared in terms of height standard deviation score (HtSDS) at the beginning of treatment and after treatment, as well as the change in HtSDS after 1 and 2 years of treatment.

RESULTS

There was no significant difference in HtSDS between the conventional and dasatinib chemotherapy groups before treatment. Within the first two years of treatment, the dasatinib chemotherapy group had a similar change trend of HtSDS as the conventional chemotherapy group. Four children in the dasatinib chemotherapy group reached the final adult height during follow-up, which was significantly lower than the target height (P=0.044). In the conventional chemotherapy group, there was no significant difference between final adult height and target height. In the dasatinib chemotherapy group, the children in adolescence had a significant change in HtSDS after treatment (P=0.032).

CONCLUSIONS

Dasatinib treatment may affect the final height of children with AML, and the use of dasatinib after the beginning of adolescence may lead to growth disorder, but dasatinib treatment has little effect on body height in the short-term treatment.

Growth Disturbances in Childhood Cancer Survivors

Survival from childhood cancer has improved dramatically over the last few decades, resulting in an increased need to address the long-term follow-up and care of childhood cancer survivors. Appropriate linear growth is an important measure of health, with alterations of growth in children and short adult height in those who have completed growth serving as potential indicators of the sequelae of the underlying diagnosis or the cancer treatments. It is therefore critical that clinicians, particularly endocrinologists, be familiar with the patterns of altered growth which may be seen following diagnosis and treatment for childhood cancer. In this article, we will review the growth alterations seen in childhood cancer survivors, focusing on risk factors and considerations in evaluation and care.

Paediatric chronic myeloid leukaemia: Is it really a different disease?

Paediatric chronic myeloid leukaemia (CML) has biological and clinical differences from adult CML. Management of paediatric CML presents unique challenges in growing children, and there are no specific guidelines for paediatric CML. This review focusses on the clinical characteristics, diagnostic issues and management of paediatric CML. Major studies that provide the basis of managing paediatric CML are summerized here. Studies conducted on adult CML patients were used to guide the management of places where studies were lacking in paediatric CML. Recently, dasatinib and nilotinib have been approved for treatment of paediatric CML, and their role has been discussed in the current management perspective. Allogeneic transplant, fertility and vaccination in paediatric CML, have also been discussed.

Longer treatment duration and history of osteoarticular symptoms predispose to tyrosine kinase inhibitor withdrawal syndrome

The effectiveness of tyrosine kinase inhibitors (TKIs) has made it possible to consider treatment discontinuation in chronic myeloid leukaemia (CML) patients that achieve an excellent response. However, a few of the patients included in the Europe Stop Tyrosine Kinase Inhibitors (EURO-SKI) trial reported musculoskeletal pain shortly after stopping TKIs, considered as a withdrawal syndrome (WS). To identify factors that may predispose to TKI WS, we analysed the pharmacovigilance declarations for the 6 months after stopping TKIs in a large cohort of CML (n = 427) that combined the French patients included in the STop IMatinib 2 (STIM2; n = 224) and EURO-SKI (n = 203) trials. Among these patients, 23% (99/427) developed TKI WS after stopping imatinib (77/373; 20·4%), nilotinib (12/29; 41·4%) or dasatinib (10/25; 40%). WS concerned mainly the upper body joints, and required multiple symptomatic treatments in 30% of patients. Univariate and multivariate analyses identified two risk factors: duration of TKI treatment [risk ratio (RR) = 1·68 (1·02-2·74)] with a 93-month cut-off time, and history of osteoarticular symptoms [RR = 1·84 (1·04-3·28)]. These findings confirm that WS is a TKI class effect. CML patients should be carefully screened before treatment initiation to identify pre-existent osteoarticular symptoms. Moreover, before TKI discontinuation, patients should be informed of the possibility of WS, particularly after a long treatment period.

Profile of Pediatric Chronic Myeloid Leukemia in the Era of Imatinib: A Study from South India

Introduction: Chronic myeloid leukemia (CML), a chronic hematologic malignancy, is rare in pediatric patients. Studies of the tyrosine kinase inhibitor imatinib are required so that uniform guidelines may focus on disease therapy and follow-up for children. We analyzed the clinicohematologic features of the disease, treatment response to imatinib, follow-up measures, and the impact of the disease on the patients and their family. Materials and Methods: All pediatric patients diagnosed with CML and treated and followed-up were studied regarding demographics, clinical features at presentation, and diagnostic profile, including laboratory parameters, peripheral blood smear test, fluorescent in situ hybridization and karyotyping, and reverse-transcriptase polymerase chain reaction for the BCR-ABL fusion gene. Treatment modalities, adverse reactions, remedial measures, assessment at every follow-up visit, patient’s education, parents’ socioeconomic status, and economic and psychological stresses were also evaluated. Results: Six patients were administered upfront therapy with a standard dose of imatinib. Hematological and biochemical parameters were monitored after the drug administration. We assessed the treatment response using molecular detection of the BCR-ABL transcripts. All patients who complied with drug therapy showed a complete molecular response and minimal toxic symptoms. However, parents found it difficult to cope socially and economically. Conclusion: Imatinib mesylate is effective and has a good molecular response, minimal toxicity, and good patient compliance. However, due to its cost, families reacquire financial debt, and the disease creates uncertainty about the child’s future, thereby necessitating psychosocioeconomic support for parents. Changes in the policies of cancer support groups are urgently needed to provide lifelong, lifesaving drugs free of cost.

Imatinib mesylate and nilotinib decrease synthesis of bone matrix in vitro

Tyrosine kinase inhibitors (TKIs), such as imatinib (IMA) and nilotinib (NIL), are the cornerstone of chronic myeloid leukemia (CML) treatment via the blockade of the oncogenic BCR-ABL1 fusion protein. However, skeletal side effects are commonly observed in pediatric patients receiving long-term treatment with IMA. Additionally, in vitro studies have shown that IMA and NIL alter vitamin D metabolism, which may further impair bone metabolism. To determine whether TKIs directly affect bone cell function, the present study treated the human osteoblastic cell line SaOS-2 with IMA or NIL and assessed effects on their mineralization capacity as well as mRNA expression of receptor activator of nuclear factor κB ligand (RANKL) and osteoprotegerin (OPG), two cytokines that regulate osteoclastogenesis. Both TKIs significantly inhibited mineralization and downregulated osteoblast marker genes, including alkaline phosphatase, osteocalcin, osterix, as well as genes associated with the pro-osteogenic Wnt signaling pathway; NIL was more potent than IMA. In addition, both TKIs increased the RANKL/OPG ratio, which is known to stimulate osteoclastogenesis. The present results suggested that the TKIs IMA and NIL directly inhibited osteoblast differentiation and directly promoted a pro-osteoclastogenic environment through the RANKL-OPG signaling axis. Thus, we propose that future work is required to determine whether the bone health of CML patients undergoing TKI-treatment should be routinely monitored.

Effect of imatinib on growth in children with chronic myeloid leukemia

Imatinib is a preferred drug for pediatric Chronic Myeloid Leukemia (CML). Long-term use has inhibitory effects on other tyrosine kinase pathways causing off-target complications such as growth impairment. Our aim was to evaluate impact of long-term use on longitudinal growth in children with CML in Kerala. We hypothesized that the impact would be lesser compared to Northern India as Kerala has the lowest rates of underweight and stunting, with a high literacy rate and per capita income. Children ≤14 years of age, diagnosed with CML and received imatinib for at least 1 year were included. Girls >9 years of age and boys >11 years were considered pubertal. Height Z scores were derived using WHO AnthroPlus. Paired t test compared difference of Z scores in prepubertal and postpubertal age groups. Height Z scores were compared with mid-parental height and sibling height Z scores. Thirty-six children were included (M = 21; F = 15). Median duration of imatinib exposure was 84 months. Decrease in longitudinal growth affected children in both prepubertal and postpubertal age groups. Decrease in height Z scores was more in prepubertal age group when imatinib therapy was initiated (p = .0018). Of 10 patients currently above 19 years (of whom 8 were in pubertal age and 2 in prepubertal age at start of imatinib) none are stunted. Patient's height Z scores was lesser compared to sibling height Z scores (p = .027). Children on continuous imatinib showed a significant stunting when treatment was initiated during prepubertal age. There is a catch-up of growth as the final height reached is within normal limits of WHO reference values.

How I treat chronic myeloid leukemia in children and adolescents

Evidence-based recommendations have been established for treatment of chronic myeloid leukemia (CML) in adults treated with tyrosine kinase inhibitors (TKIs), but the rarity of this leukemia in children and adolescents makes it challenging to develop similar recommendations in pediatrics. In addition to imatinib, which was approved for pediatric CML in 2003, the second-generation TKIs dasatinib and nilotinib were recently approved for use in children, expanding the therapeutic options and pushing allogeneic stem cell transplantation to a third-line treatment of most pediatric cases. Yet, without sufficient data on efficacy and safety specific to pediatric patients, the selection of a TKI continues to rely on clinical experience in adults. Here, we present 4 case scenarios highlighting common yet challenging issues encountered in the treatment of pediatric CML (suboptimal response, poor treatment adherence, growth retardation, and presentation in advanced phases). Limited experience with very young children, the transition of teenagers to adult medicine, and the goal of achieving treatment-free remission for this rare leukemia are additional significant obstacles that require further clinical investigation through international collaboration.

Hypothalamic-Pituitary and Growth Disorders in Survivors of Childhood Cancer: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

To formulate clinical practice guidelines for the endocrine treatment of hypothalamic-pituitary and growth disorders in survivors of childhood cancer.

PARTICIPANTS

An Endocrine Society-appointed guideline writing committee of six medical experts and a methodologist.

CONCLUSIONS

Due to remarkable improvements in childhood cancer treatment and supportive care during the past several decades, 5-year survival rates for childhood cancer currently are >80%. However, by virtue of their disease and its treatments, childhood cancer survivors are at increased risk for a wide range of serious health conditions, including disorders of the endocrine system. Recent data indicate that 40% to 50% of survivors will develop an endocrine disorder during their lifetime. Risk factors for endocrine complications include both host (e.g., age, sex) and treatment factors (e.g., radiation). Radiation exposure to key endocrine organs (e.g., hypothalamus, pituitary, thyroid, and gonads) places cancer survivors at the highest risk of developing an endocrine abnormality over time; these endocrinopathies can develop decades following cancer treatment, underscoring the importance of lifelong surveillance. The following guideline addresses the diagnosis and treatment of hypothalamic-pituitary and growth disorders commonly encountered in childhood cancer survivors.

New Agents, Emerging Late Effects, and the Development of Precision Survivorship

Incremental improvements in the treatment of children and adolescents with cancer have led to 5-year survival rates reaching nearly 85%. In the past decade, impressive progress has been made in understanding the biology of many pediatric cancers. With that understanding, multiple new agents have become available that offer the promise of more-effective and less-toxic treatment. These include agents that target various cell surface antigens and engage the adaptive immune system, as well as those that interfere with key signaling pathways involved in tumor development and growth. For local control, surgery and radiation techniques also have evolved, becoming less invasive or featuring new techniques and particles that more precisely target the tumor and limit the dose to normal tissue. Nevertheless, targeted agents, like conventional chemotherapy, radiotherapy, and surgery, may have off-target effects and deserve long-term follow-up of their safety and efficacy. These include injury to the endocrine, cardiovascular, and immunologic systems. New radiation and surgical techniques that theoretically reduce morbidity and improve long-term quality of life must also be validated with actual patient outcomes. Finally, with advances in genomics, information on host susceptibility to late effects is beginning to emerge. Such knowledge, coupled with improved metrics that better describe the spectrum of potential late effects across the entire lifespan, can lead to the development of decision models that project the potential long-term health outcomes associated with various treatment and follow-up strategies. These developments will help extend the current focus on precision medicine to precision survivorship, where clinicians, patients, and families will have a better grasp of the potential risks, benefits, and tradeoffs associated with the growing number of cancer treatment options.

Front-line imatinib treatment in children and adolescents with chronic myeloid leukemia: results from a phase III trial

A total of 156 patients (age range 1.3-18.0 years, median 13.2 years; 91 (58.3%) male) with newly diagnosed CML (N = 146 chronic phase (CML-CP), N = 3 accelerated phase (CML-AP), N = 7 blastic phase (CML-BP)) received imatinib up-front (300, 400, 500 mg/m², respectively) within a prospective phase III trial. Therapy response, progression-free survival, causes of treatment failure, and side effects were analyzed in 148 children and adolescents with complete data. Event-free survival rate by 18 months for patients in CML-CP (median follow-up time 25 months, range: 1-120) was 97% (95% CI, 94.2-99.9%). According to the 2006 ELN-criteria complete hematologic response by month 3, complete cytogenetic response (CCyR) by month 12, and major molecular response (MMR) by month 18 were achieved in 98, 63, and 59% of the patients, respectively. By month 36, 86% of the patients achieved CCyR and 74% achieved MMR. Thirty-eight patients (27%) experienced imatinib failure because of unsatisfactory response or intolerance (N = 9). In all, 28/148 patients (19%) underwent stem cell transplantation (SCT). In the SCT sub-cohort 2/23 patients diagnosed in CML-CP, 0/1 in CML-AP, and 2/4 in CML-BP, respectively, died of relapse (N = 3) or SCT-related complications (N = 2). This large pediatric trial extends and confirms data from smaller series that first-line imatinib in children is highly effective.

Imatinib Inhibits GH Secretion From Somatotropinomas

Background: Imatinib, a tyrosine kinase inhibitor, causes growth failure in children with chronic myeloid leukemia probably by targeting the growth hormone (GH)/insulin like growth factor-1 (IGF-1) axis. We aim to explore the imatinib targets expression in pituitary adenomas and study the effect of imatinib on GH secretion in somatotropinoma cells and GH3 cell line. Materials and Methods: The expression pattern of imatinib's targets (c-kit, VEGF, and PDGFR-α/β) was studied using immunohistochemistry and immunoblotting 157 giant (≥4 cm) pituitary adenomas (121 non-functioning pituitary adenomas, 32 somatotropinomas, and four prolactinomas) and compared to normal pituitary (n = 4) obtained at autopsy. The effect imatinib on GH secretion, cell viability, immunohistochemistry, electron microscopy, and apoptosis was studied in primary culture of human somatotropinomas (n = 20) and in rat somato-mammotroph GH3 cell-line. A receptor tyrosine kinase array was applied to human samples to identify altered pathways. Results: Somatotropinomas showed significantly higher immunopositivity for c-kit and platelet-derived growth factor receptor-β (PDGFR-β; P < 0.009 and P < 0.001, respectively), while staining for platelet-derived growth factor receptor-α (PDGFR-α) and vascular endothelial growth factor (VEGF) revealed a weaker expression (P < 0.001) compared to normal pituitary. Imatinib inhibited GH secretion from both primary culture (P < 0.01) and GH3 cells (P < 0.001), while it did not affect cell viability and apoptosis. The receptor tyrosine kinase array showed that imatinib inhibits GH signaling via PDGFR-β pathway. Conclusion: Imatinib inhibits GH secretion in somatotropinoma cells without affecting cell viability and may be used as an adjunct therapy for treating GH secreting pituitary adenomas.