Imatinib has adverse effect on growth in children with chronic myeloid leukemia

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.

Demographic and disease-related factors impact bone turnover and vitamin D in children with hemato-oncological diseases

Children with hemato-oncological diseases may have significant skeletal morbidity, not only during and after treatment but also at the time of diagnosis before cancer treatment. This study was designed to evaluate the vitamin D status and circulating bone metabolic markers and their determinants in children at the time of diagnostic evaluation for hemato-oncological disease. This cross-sectional study included 165 children (91 males, median age 6.9 yr range 0.2-17.7 yr). Of them, 76 patients were diagnosed with extracranial or intracranial solid tumors, 83 with leukemia, and 6 with bone marrow failure. Bone metabolism was assessed by measuring serum 25OHD, PTH, bone alkaline phosphatase, intact N-terminal propeptide of type I procollagen, and C-terminal cross-linked telopeptide of type I collagen. Vitamin D deficiency was found in 30.9% of children. Lower 25OHD levels were associated with older age, lack of vitamin D supplementation, season outside summer, and a country of parental origin located between latitudes -45° and 45°. Children diagnosed with leukemia had lower levels of markers of bone formation and bone resorption than those who had solid tumors or bone marrow failure. In conclusion, vitamin D deficiency was observed in one-third of children with newly diagnosed cancer. Bone turnover markers were decreased in children with leukemia, possibly because of the suppression of osteoblasts and osteoclasts by leukemic cells. The identification of patients with suboptimal vitamin D status and compromised bone remodeling at cancer diagnosis may aid in the development of supportive treatment to reduce the adverse effects of cancer and its treatment.

Bosutinib in Resistant and Intolerant Pediatric Patients With Chronic Phase Chronic Myeloid Leukemia: Results From the Phase I Part of Study ITCC054/COG AAML1921

PURPOSE

Bosutinib is approved for adults with chronic myeloid leukemia (CML): 400 mg once daily in newly diagnosed (ND); 500 mg once daily in resistant/intolerant (R/I) patients. Bosutinib has a different tolerability profile than other tyrosine kinase inhibitors (TKIs) and potentially less impact on growth (preclinical data). The primary objective of this first-in-child trial was to determine the recommended phase II dose (RP2D) for pediatric R/I and ND patients.

PATIENTS AND METHODS

In the phase I part of this international, open-label trial (ClinicalTrials.gov identifier: NCT04258943), children age 1-18 years with R/I (per European LeukemiaNet 2013) Ph+ CML were enrolled using a 6 + 4 design, testing 300, 350, and 400 mg/m2 once daily with food. The RP2D was the dose resulting in 0/6 or 1/10 dose-limiting toxicities (DLTs) during the first cycle and achieving adult target AUC levels for the respective indication. As ND participants were only enrolled in phase II, the ND RP2D was selected based on data from R/I patients.

RESULTS

Thirty patients were enrolled; 27 were evaluable for DLT: six at 300 mg/m2, 11 at 350 mg/m2 (one DLT), and 10 at 400 mg/m2 (one DLT). The mean AUCs at 300 mg/m2, 350 mg/m2, and 400 mg/m2 were 2.20 μg h/mL, 2.52 μg h/mL, and 2.66 μg h/mL, respectively. The most common adverse event was diarrhea (93%; ≥grade 3: 11%). Seven patients stopped because of intolerance and eight because of insufficient response. Complete cytogenetic and major molecular response to bosutinib appeared comparable with other published phase I/II trials with second-generation TKIs in children.

CONCLUSION

Bosutinib was safe and effective. The pediatric RP2D was 400 mg/m2 once daily (max 600 mg/d) with food in R/I patients and 300 mg/m2 once daily (max 500 mg/d) with food in ND patients, which achieved targeted exposures as per adult experience.

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.

Continuous therapy response references for BCR::ABL1 monitoring in pediatric chronic myeloid leukemia

Response to tyrosine kinase inhibitor (TKI) therapy in patients with chronic myeloid leukemia (CML) is monitored by quantification of BCR::ABL1 transcript levels. Milestones for assessing optimal treatment response have been defined in adult CML patients and are applied to children and adolescents although it is questionable whether transferability to pediatric patients is appropriate regarding genetic and clinical differences. Therefore, we analyzed the molecular response kinetics to TKI therapy in 129 pediatric CML patients and investigated whether response assessment based on continuous references can support an early individual therapy adjustment. We applied a moving quantiles approach to establish a high-resolution response target curve and contrasted the median responses in all patients with the median of the ideal target curve obtained from a subgroup of optimal responders. The high-resolution response target curve of the optimal responder group presents a valuable tool for continuous therapy monitoring of individual pediatric CML patients in addition to the fixed milestones. By further comparing BCR::ABL1 transcript levels with BCR::ABL1 fusion gene copy numbers, it is also possible to model the differential dynamics of BCR::ABL1 expression and cell number under therapy. The developed methodology can be transferred to other biomarkers for continuous therapy monitoring.

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.

Alterations in cellular metabolisms after TKI therapy for Philadelphia chromosome-positive leukemia in children: A review

Incidence rates of chronic myeloid leukemia (CML) and Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) are lower but more aggressive in children than in adults due to different biological and host factors. After the clinical application of tyrosine kinase inhibitor (TKI) blocking BCR/ABL kinase activity, the prognosis of children with CML and Ph+ ALL has improved dramatically. Yet, off-target effects and drug tolerance will occur during the TKI treatments, contributing to treatment failure. In addition, compared to adults, children may need a longer course of TKIs therapy, causing detrimental effects on growth and development. In recent years, accumulating evidence indicates that drug resistance and side effects during TKI treatment may result from the cellular metabolism alterations. In this review, we provide a detailed summary of the current knowledge on alterations in metabolic pathways including glucose metabolism, lipid metabolism, amino acid metabolism, and other metabolic processes. In order to obtain better TKI treatment outcomes and avoid side effects, it is essential to understand how the TKIs affect cellular metabolism. Hence, we also discuss the relevance of cellular metabolism in TKIs therapy to provide ideas for better use of TKIs in clinical practice.

Physician risk perceptions and surveillance practices for tyrosine kinase inhibitor long-term effects in pediatric CML

Chronic myeloid leukemia (CML) is effectively treated with long-term tyrosine kinase inhibitor (TKI) therapy, yet little is known about risks of prolonged TKI exposure in young patients, and long-term effect monitoring is not standardized. We surveyed North American pediatric oncologists (n = 119) to evaluate perceived risk of and surveillance practices for potential toxicities associated with prolonged TKI exposure in children and adolescents/young adults (AYAs) with CML. Survey domains included general and specific risk perceptions and surveillance practices for asymptomatic patients on chronic TKI therapy. We analyzed data descriptively and explored relationships between risk perceptions and surveillance. Risk perceptions varied among oncologists but were similar across six categories (thyroid, cardiac, vascular, metabolic, fertility, psychologic), with less than one-third rating each risk as moderate or high in pediatric and AYA patients. More oncologists perceived moderate or high risk of growth abnormalities in children (62% pediatric, 14% AYA) and financial toxicity in all patients (60% pediatric, 64% AYA). A greater proportion of oncologists with moderate or high perceived risk of thyroid abnormalities reported testing thyroid function compared to those with lower perceived risk; patterns for metabolic risk/lipid tests and cardiac risk/tests were similar. In summary, we found that pediatric oncologists had variable risk perceptions and surveillance practices for potential toxicities associated with prolonged TKI exposure. Standardizing surveillance would help quantify risks and refine recommendations.Supplemental data for this article is available online at https://doi.org/10.1080/08880018.2021.2017085 .

Real-World Experience of Treating Pediatric Chronic Myeloid Leukemia: Retrospective Study from a Cancer Center in Southern India

Introduction Chronic myeloid leukemia (CML) is rare in children and constitutes 2% of all leukemia. We present our institute experience in treating pediatric CML for 20 years.

Objectives There is a paucity of data on pediatric CML from India, hence we would like to present treatment responses and survival rates in our pediatric population treated with tyrosine kinase inhibitors at our center.

Materials and Methods Patients aged less than 18 years, diagnosed with CML from 2000 to 2019, and treated with imatinib were analyzed retrospectively considering demographic features, treatment characteristics, and survival outcomes. Descriptive analysis was done for the baseline characteristics. Event-free survival (EFS) and overall survival (OS) were calculated using the Kaplan-Meier method and the factors were compared using the log-rank test.

Results During the study period, 95 patients were diagnosed with CML of which 54 (56.8%) were males. The most common stage at presentation was the chronic phase (CP) with 84 (88.4%) patients followed by accelerated phase (AP) and blast crisis (BC) with 6 (6.3%) and 5 (5.3%) patients respectively. The median duration of follow-up for all patients was 98 months. EFS and OS at 8 years for patients with CML-CP were 43.1% and 80.4% respectively. Complete hematological response, complete cytogenetic response, and major molecular response was documented in 91 (95.7%), 73 (76.8%), and 63 (66.3%) patients respectively.

Conclusion Outcomes in pediatric CML are comparable to that of adults. Imatinib is well tolerated in children.

Vemurafenib provides a rapid and robust clinical response in pediatric Langerhans cell histiocytosis with the BRAF V600E mutation but does not eliminate low-level minimal residual disease per ddPCR using cell-free circulating DNA

BACKGROUND

Langerhans cell histiocytosis (LCH) is a disease that arises from myeloid cells that phenotypically resemble Langerhans cells (LC), which is typically driven by the BRAF V600E mutation. High-risk LCH has a poor prognosis.

PROCEDURE

Fifteen children with BRAF V600E + LCH received vemurafenib between March 2016 and February 2020. The median age at LCH onset was 2 months and the median age at the start of vemurafenib treatment was 22 months. The median disease activity score (DAS) at the start of vemurafenib treatment was 12 points.

RESULTS

The median duration of vemurafenib treatment was 29 months. All patients responded to treatment, with median DAS of 4 points at week 4 and 1 point at 6 months. Two patients died: 1 of hepatic failure after NSAID overdose and 1 of neutropenic sepsis. Cessation of vemurafenib resulted in relapse in 5 patients and was only possible for 1 patient. Serial measurements of BRAF V600E using cell-free circulating DNA revealed that 7 patients had persistently high mutant allele levels.

CONCLUSION

Vemurafenib is effective in children with BRAF V600E + LCH. However, treatment with vemurafenib does not eradicate the disease and its long-term toxicity has not been established.

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.

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.

Chronic Myelogenous Leukemia in Childhood

PURPOSE OF REVIEW

Chronic myelogenous leukemia (CML) is rare in children, requiring extrapolation from treatment of adults. In this review, we explore similarities and differences between adult and pediatric CML with a focus on therapeutic advances and emerging clinical questions.

RECENT FINDINGS

Pediatric CML is effectively treated with long-term targeted therapy using tyrosine kinase inhibitors (TKIs). Newly diagnosed pediatric patients in chronic phase can now be treated with imatinib, dasatinib, or nilotinib without allogeneic hematopoietic stem cell transplantation. While treatment-free remission is possible in adults in chronic phase with optimal response to therapy, data are currently insufficient to support stopping TKI in pediatrics outside of a clinical trial. Knowledge gaps remain regarding long-term and late effects of TKIs in pediatric CML. Targeted therapy has markedly improved outcomes for pediatric CML, while raising a number of clinical questions, including the possibility of treatment-free remission and long-term health implications of prolonged TKI exposure at a 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.

[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。

Imatinib-Induced Hypogammaglobulinemia in Children and Adolescents with Chronic Myeloid Leukemia

Imatinib-induced tyrosine kinase inhibition extends beyond the BCR-ABL mutation, resulting in adverse effects. We evaluated hypogammaglobulinemia as a potential 'off-target' action of imatinib in children with CML. A cross-sectional, observational study was performed. Patients with CML in chronic phase, age <18-years at diagnosis, receiving imatinib for a duration exceeding 6-months were enrolled. Serum immunoglobulin G, A, and M were measured by end-point nephelometry. Thirty patients were enrolled. The mean age at diagnosis was 10.4 ± 3.1 years (range: 5-18). The mean age at enrollment was 16.4 ± 4.1 years (range: 9-23). The median dose of imatinib was 287.5 mg/m² (IQR: 267.3, 345.0). The median duration of imatinib-therapy was 6-years (IQR: 3.0, 10.3). The median (IQR) normalized levels of IgG, IgA, and IgM were 33.0% (IQR: -12.8, 58.7), 28.1% (IQR: -17.0, 90.1) and 15.9% (IQR: -9.3, 40.5), respectively. The IgG, IgA, and IgM levels were reduced in 9 (30%), 8 (27%), and 10 (33%) patients, respectively. Five (17%) patients had pan-hypogammaglobulinemia. We suggest checking immunoglobulin levels in patients with CML receiving imatinib with recurrent/unusual infections.

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.

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.

Discontinuation of Imatinib in a Child With Chronic Myeloid Leukemia

Chronic myeloid leukemia (CML) has different disease biology with a more aggressive clinical course in children. Achieving treatment-free remission is the ideal goal for the pediatric CML population to avoid long-term toxicities of tyrosine kinase inhibitors. Here, we present our experience of stopping Imatinib in a pediatric patient of CML who had excessive weight gain with Imatinib. He is currently maintaining treatment-free remission for 15 months after stopping therapy at the time of last follow-up. The patient also had normalization of body mass index with the stopping of Imatinib.

[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.

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.

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.

Imatinib: Major photocatalytic degradation pathways in aqueous media and the relative toxicity of its transformation products

Imatinib (IMA) is a highly potent tyrosine kinase inhibitor used as first-line anti-cancer drug in the treatment of chronic myeloid leukemia. Due to its universal mechanism of action, IMA also has endocrine and mutagenic disrupting effects in vivo and in vitro, which raises the question of its environmental impact. However, to date, very little information is available on its environmental fate and the potential role of its transformation products (TPs) on aquatic organisms. Given the IMA resistance to hydrolysis and direct photolysis according to the literature, we sought to generate TPs through oxidative and radical conditions using the AOPs pathway. Thus, the reactivity of the cytotoxic drug IMA in water in the presence of OH and h+ was investigated for the first time in the present work. In this regard, a non-targeted screening approach was applied in order to reveal its potential TPs. The tentative structural elucidation of the detected TPs was performed by LC-HRMSⁿ. The proposed approach allowed detecting a total of twelve TPs, among which eleven are being described for the first time in this work. Although the structures of these TPs could not be positively confirmed due to lack of standards, their chemical formulas and product ions can be added to databases, which will allow their screening in future monitoring studies. Using the quantitative structure-activity relationship (QSAR) approach and rule-based software, we have shown that the detected TPs possess, like their parent molecule, comparable acute toxicity as well as mutagenic and estrogenic potential. In addition to the in silico studies, we also found that the samples obtained at different exposure times to oxidative conditions, including those where IMA is no longer detected, retained toxicity in vitro. Such results suggest further studies are needed to increase our knowledge of the impact of imatinib on the environment.

Precision medicine in pediatric oncology

Outcome in treatment of childhood cancers has improved dramatically since the 1970s. This success was largely achieved by the implementation of cooperative clinical research trial groups that standardized and developed treatment of childhood cancer. Nevertheless, outcome in certain types of malignancies is still unfavorable. Intensification of conventional chemotherapy and radiotherapy improved outcome only marginally at the cost of acute and long-term side effects. Hence, it is necessary to develop targeted therapy strategies.Here, we review the developments and perspectives in precision medicine in pediatric oncology with a special focus on targeted drug therapies like kinase inhibitors and inducers of apoptosis, the impact of cancer genome sequencing and immunotherapy.

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.

Comparative Study of Clinico-hematological Features, Molecular Spectrum and Response to Imatinib in Chronic Myelogenous Leukemia Patients: Pediatric and Adolescent Versus Adults

Chronic myelogenous leukemia (CML) is a rare disease in children, accounting for approximately 3% of leukemias in children and adolescents, with an annual incidence of 1 case per million children in western countries. This study was conducted, at PGIMER, Chandigarh. Ninety eight patients, 48 in children and adolescents group, and 50 in adult group were included in the study. Their hematological profiles along with the bone marrow findings were analyzed. The diagnosis of CML was confirmed by cytogenetics and/or molecular analysis. The complete hematological response (CHR) was analyzed at 3 months and cytogentic response (CgR) at 12 months after starting imatinib therapy. Compared to adults, pediatric and adolescent patients were more symptomatic at presentation (93.5 vs. 75%). Among symptomatic patients, massive splenomegaly (>10 cm), higher total leucocyte and platelet counts were seen more frequently in pediatric patients. The most common transcript in both groups was e14a2. The distribution of pediatric and adolescent cases in Sokal, Hasford and EUTOS score, showed only statistically significant difference for low risk Sokal group, which had more patients in pediatric group. Compared to adults, pediatric and adolescent patients had similar CHR rate (91.3 vs. 92%), but showed lesser major CgR rate (90.9 vs. 95.5%) however, this was not statistically significant.

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.

Pharmacology and pharmacokinetics of imatinib in pediatric patients

INTRODUCTION

The tyrosine kinase inhibitor (TKI) imatinib was rationally designed to target BCR-ABL1 which is constitutively activated in chronic myeloid leukemia (CML). Following the tremendous success in adults, imatinib also became licensed for treatment of CML in minors. The rarity of pediatric CML hampers the conduction of formal trials. Thus, imatinib is still the single TKI approved for CML treatment in childhood. Areas covered: This review attempts to provide an overview of the literature on pharmacology, pharmacokinetic, and pharmacogenetic of imatinib concerning pediatric CML treatment. Articles were identified through a PubMed search and by reviewing abstracts from relevant hematology congresses. Additional information was provided from the authors' libraries and expertise and from our own measurements of imatinib trough plasma levels in children. Pharmacokinetic variables (e.g. alpha 1-acid glycoprotein binding, drug-drug/food-drug interactions via cytochrome P450 3A4/5, cellular uptake mediated via OCT-1-influx variations and P-glycoprotein-mediated drug efflux) still await to be addressed in pediatric patients systematically. Expert commentary: TKI response rates vary among different individuals and pharmacokinetic variables all can influence CML treatment success. Adherence to imatinib intake may be the most prominent factor influencing treatment outcome in teenagers thus pointing towards the potential benefits of regular drug monitoring.

Chronic Myeloid Leukemia in India

Background

In the last decade, the use of imatinib has brought a paradigm shift in the management of chronic myeloid leukemia (CML). In India, imatinib has been available for more than a decade and has been made accessible to all segments of the population because of patient assistance programs and cheaper generic versions. Despite improvements in survival, there are unique challenges in the Indian context.

Methods

We reviewed published data pertaining to CML in India for the period of 1990 to 2016, using PubMed advanced search with the terms chronic myeloid leukemia and India, and included studies that reported on epidemiology, monitoring for therapy, treatment outcomes, and resistance. Additionally, the references in retrieved articles were also reviewed.

Results

Thirty-seven studies were identified. The incidence of CML may be slightly lower in India than in the West, but there was only a single article reporting population-based data. Indian patients presented with more advanced disease. Most centers have access to imatinib as first-line therapy, but there is limited availability of molecular monitoring and second-line therapy. Most of the outcome data were retrospective but seemed comparable with that reported in Western centers. Drug adherence was impaired in at least one third of patients and contributed to poor survival.

Conclusion

Focused prospective studies and cooperative studies might improve the quality of data available. Future studies should focus on adherence, its effects on outcomes, and methods to address this problem.

Prognostic factors and treatment of pediatric acute lymphoblastic leukemia

The event-free survival (EFS) for pediatric acute lymphoblastic leukemia (ALL) has shown remarkable improvement in the past several decades. In Korea also, a recent study showed 10-year EFS of 78.5%. Much of the improved outcome for pediatric ALL stems from the accurate identification of prognostic factors, the designation of risk group based on these factors, and treatment of appropriate duration and intensity according to risk group, done within the setting of cooperative clinical trials. The schema of first-line therapy for ALL remains mostly unchanged, although many groups have now reported on the elimination of cranial irradiation in all patients with low rates of central nervous system relapse. Specific high risk subgroups, such as Philadelphia chromosome-positive (Ph+) ALL and infant ALL continue to have significantly lower survival than other ALL patients. The introduction of tyrosine kinase inhibitors into therapy has led to enhanced outcome for Ph+ ALL patients. Infant ALL patients, particularly those with MLL rearrangements, continue to have poor outcome, despite treatment intensification including allogeneic hematopoietic cell transplantation. Relapsed ALL is a leading cause of mortality in pediatric cancer. Recent advances in immunotherapy targeting the CD19 of the ALL blast have shown remarkable efficacy in some of these relapsed and refractory patients. With improved survival, much of the current focus is on decreasing the long-term toxicities of treatment.

Adverse effects of imatinib in children with chronic myelogenous leukemia

BACKGROUND

Imatinib mesylate (IM) is a selective tyrosine kinase inhibitor and is approved for indefinite treatment of pediatric chronic myelogenous leukemia (CML). Potential side-effects regarding growth failure and bone metabolism have been reported but data are still scarce in pediatric CML.

METHODS

Six chronic-phase CML children on IM treatment with a median age of 9.87 years (range, 5.33-12.67 years) were enrolled in the study. Growth, bone mineral density (BMD), bone parameters, 25(OH)-vitamin D3 (25-OHD3) and blood tests including parathyroid hormone, insulin-like growth factor-1 (IGF-1), IGF binding protein 3, thyroid function test and sex hormones were assessed.

RESULTS

Median duration of IM treatment was 78.5 months. Height velocity was suppressed during the first 30 months of treatment and improved gradually afterwards. Two patients (33.3%) had decreased lumbar spine BMD z-scores (<1.5 SD). Patients with decreased BMD had higher mean IM exposure time than those with normal BMD. The majority of patients (n = 5) had low 25-OHD3 (<30 ng/mL), but there was no correlation between BMD and 25-OHD3 status. Other blood tests were normal.

CONCLUSIONS

This study supports and confirms the need for monitoring the side-effects of IM treatment on growth, bone density and vitamin D status in pediatric CML. Prolonged IM treatment was associated with low BMD without disturbing bone parameters. There was high prevalence of vitamin D insufficiency. Therefore, the beneficial effect of vitamin D supplement should be explored with regard to the effects on height velocity and BMD in CML patients with vitamin D insufficiency.

Survival trends in childhood chronic myeloid leukaemia in Southern-Eastern Europe and the United States of America

AIM

To assess trends in survival and geographic disparities among children (0-14 years) with chronic myeloid leukaemia (CML) before and after the introduction of molecular therapy, namely tyrosine kinase inhibitors (TKIs) in Southern-Eastern European (SEE) countries and the USA.

METHODS

We calculated survival among children with CML, acute lymphoblastic (ALL) and acute myeloid leukaemia (AML) in 14 SEE (1990-2014) cancer registries and the U.S. Surveillance, Epidemiology and End Results Program (SEER, 1990-2012). We used Kaplan-Meier curves and multivariate Cox regression models to calculate hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

Among 369 CML cases, substantial improvements were noted in 2-year survival during the post-TKI (range: 81-89%) compared to pre-TKI period (49-66%; HR: 0.37, 95% CI: 0.23-0.60). Risk of death was three times higher for <5-year-old children versus those aged 10-14 years (HR: 3.03, 95% CI: 1.85-4.94) and 56% higher for those living in SEE versus SEER (HR: 1.56, 95% CI: 1.01-2.42). Regardless of geographic area and period of TKI administration, however, age seems to be a significant determinant of CML prognosis (pre-TKI period, HR_0-4y: 2.71, 95% CI: 1.53-4.79; post-TKI period, HR_0-4y: 3.38, 95% CI: 1.29-8.85). Noticeably, post-TKI survival in CML overall approximates that for ALL, whereas therapeutic advancements for AML remain modest.

CONCLUSION

Registry data show that introduction of molecular therapies coincides with revolutionised therapeutic outcomes in childhood CML entailing dramatically improved survival which is now similar to that in ALL. Given that age disparities in survival remain substantial, offering optimal therapy to entire populations is an urgent priority.

Recognizing Endocrinopathies Associated With Tyrosine Kinase Inhibitor Therapy in Children With Chronic Myelogenous Leukemia

Side effects of tyrosine kinase inhibitor (TKI) treatment vary in children and adults with chronic myelogenous leukemia (CML). As children have a much longer life expectancy than adults, TKI therapy may continue for decades and with long-term consequences that differ from adults. Children may develop endocrinopathies related to "off-target" effects of TKIs, such as delayed growth, changes in bone metabolism, thyroid abnormalities, and effects on puberty and fertility. These endocrinopathies present additional challenges for pediatric patients with CML. This review critically evaluates the literature on long-term endocrine side effects of TKIs in the pediatric CML population and provides suggested recommendations.

Outcomes of Allogeneic Hematopoietic Cell Transplantation in Children and Young Adults with Chronic Myeloid Leukemia: A CIBMTR Cohort Analysis

Chronic myeloid leukemia (CML) in children and young adults is uncommon. Young patients have long life expectancies and low morbidity with hematopoietic cell transplantation (HCT). Prolonged tyrosine kinase inhibitor (TKI) use may cause significant morbidity. In addition, indication for HCT in patients in the first chronic phase is not established. We hence retrospectively evaluated outcomes in 449 CML patients with early disease receiving myeloablative HCT reported to the CIBMTR. We analyzed various factors affecting outcome, specifically the effect of age and pre-HCT TKI in pediatric patients (age < 18 years, n = 177) and young adults (age 18 to 29 years, n = 272) with the goal of identifying prognostic factors. Post-HCT probability rates of 5-year overall survival (OS) and leukemia-free survival (LFS) were 75% and 59%, respectively. Rates of OS and LFS were 76% and 57% in <18-year and 74% and 60% in 18- to 29-year group, respectively, by univariate analysis (P = .1 and = .6). Five-year rates of OS for HLA matched sibling donor (MSD) and bone marrow (BM) stem cell source were 83% and 80%, respectively. In multivariate analysis there was no effect of age (<18 versus 18 to 29) or pre-HCT TKI therapy on OS, LFS, transplant related mortality, or relapse. Favorable factors for OS were MSD (P < .001) and recent HCT (2003 to 2010; P = .04). LFS was superior with MSD (P < .001), BM as graft source (P = .001), and performance scores > 90 (P = .03) compared with unrelated or mismatched peripheral blood stem cells donors and recipients with lower performance scores. Older age was associated with increased incidence of chronic graft-versus-host disease (P = .0002). In the current era, HCT outcomes are similar in young patients and children with early CML, and best outcomes are achieved with BM grafts and MSD.

Optimal management for pediatric chronic myeloid leukemia

Chronic myeloid leukemia (CML) is rare among childhood leukemias. Its incidence increases with age, from 0.09/100 000 at ≤15 years old to 7.88/100 000 at ≥75 years old. There are several biological and clinical differences between pediatric and adult CML. Markedly increased leukocyte count and a higher incidence of splenomegaly are characteristic features at diagnosis in pediatric patients. The therapeutic approach to CML has changed since the introduction of the tyrosine kinase inhibitor (TKI) imatinib, followed by dasatinib and nilotinib. Given the efficacy of TKI in adult CML, TKI are regarded as the established first-line treatment in adult patients. In 2011, a prospective phase IV study in pediatric patients showed the excellent efficacy and safety of imatinib. Imatinib is also accepted as a first-line option for childhood chronic phase CML. Although the efficacy of dasatinib and nilotinib reported in adult studies seems very attractive for pediatric patients, neither drug has been prospectively investigated in a large pediatric cohort. TKI are designed to inhibit BCR-ABL1 kinase, but they have unfavorable effects, so-called "off-target" complications, such as growth impairment. Long-term morbidity due to TKI is unknown. Furthermore, the adverse effects on growing children have not been clearly elucidated, even though the exposure period to imatinib is relatively short. To establish the standard therapeutic management for pediatric CML, it is important to prospectively confirm the attractive outcomes obtained in adult studies via pediatric clinical trials with a careful monitoring system for TKI-induced adverse effects, especially in growing children.

How can we improve on the already impressive results in pediatric ALL?

The past 70 years have seen childhood acute lymphoblastic leukemia move from a fatal disease with a survival of barely 4 months to a curable disease in >85% of patients. It has become clear that as treatment has intensified, more children are cured but at the expense of increased toxicity which for some can cause significant long-term morbidity and even mortality. The drive in more recent years has been to identify sensitive markers of disease and response to treatment to allow a reduction in therapy in those who do not require it and more intensive treatment in those who do. Clinical characteristics have been used to stratify patients into different risk groups and this, coupled with following response at a molecular level, has done much to tailor treatment to the patient. Considerable research has been focused on the molecular characteristics of the leukemia itself to elucidate the biologic mechanisms underlying both the disease and the comparative or absolute resistance of some types of leukemia. These molecular markers can also act as targets for novel therapies, which require newer trial methodologies to prove their utility. There has been less focus on the biology of the patient but it is clear that some patients are more susceptible to adverse events and toxicities than others. Through the use of pharmacogenomics, modification to therapy may be appropriate in certain patients based on their genetic profile. As novel therapies become available, suitable controlled trials in children are essential for their safe use in this population and will ensure that children are not denied timely access to advances in treatment.