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

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.

Chronic myeloid leukemia (CML) in children and adolescents-Clinicopathological findings

BACKGROUND

Barely two per million Belgian children/adolescents are diagnosed with chronic myeloid leukemia (CML) annually. In this retrospective study, we aimed to investigate the diagnostic features, clinical and laboratory characteristics, and treatment outcome of this rare entity.

METHODS

Medical records of all pediatric CML patients (age ≤ 17 years) diagnosed at the University Hospitals Leuven between 1986 and 2021 were reviewed.

RESULTS

Fourteen patients (median age at diagnosis 12.5 years) were included, all presenting in chronic phase. Five patients were diagnosed before 2003; main therapy included hydroxyurea (n = 5/5), interferon-alfa (n = 3/5) and allogeneic hematopoietic stem cell transplantation (allo-Tx) (n = 3/5). Complete hematologic response (CHR), complete cytogenetic response (CCyR) and major molecular response (MMR) was reached in resp. 4/5, 4/5 and in 2/3 of evaluable patients. Three patients progressed to accelerated/blast phase (median time 19 months) and 1/5 is alive and disease-free at last follow-up. Nine patients were diagnosed after 2003 and were treated with first generation (1°G) tyrosine kinase inhibitors (TKI): 3/9 subsequently underwent an allo-Tx, 4/9 were switched to 2°G TKI, one patient was additionally switched to 3°G TKI. CHR, CCyR and MMR was reached in 9/9, 9/9 and 8/9 of these patients. No progression to accelerated/blast phase was observed and none of these patients deceased. At last follow-up, 7/9 patients were in MMR or disease free, the two remaining patients did not reach or lost MMR, both related to compliance issues.

CONCLUSION

Our study confirmed that TKI significantly improved the prognosis of pediatric CML. However, drug compliance poses a considerable challenge.

Therapeutic drug monitoring of imatinib - how far are we in the leukemia setting?

INTRODUCTION

Tyrosine kinase inhibitors (TKIs) have revolutionized survival rates of chronic myeloid leukemia (CML) and Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) and replaced hematopoietic stem cell transplantation (hSCT) as the key treatment option for these patients. More recently, the so-called Philadelphia chromosome-like (Ph-like) ALL has similarly benefitted from TKIs. However, many patients shift from the first generation TKI, imatinib, due to treatment-related toxicities or lack of treatment efficacy. A more personalized approach to TKI treatment could counteract these challenges and potentially be more cost-effective. Therapeutic drug monitoring (TDM) has led to higher response rates and less treatment-related toxicity in adult CML but is rarely used in ALL or in childhood CML.

AREAS COVERED

This review summarizes different antileukemic treatment indications for TKIs with focus on imatinib and its pharmacokinetic/-dynamic properties as well as opportunities and pitfalls of TDM for imatinib treatment in relation to pharmacogenetics and co-medication for pediatric and adult Ph+/Ph-like leukemias.

EXPERT OPINION

TDM of imatinib adds value to standard monitoring of ABL-class leukemia by uncovering non-adherence and potentially mitigating adverse effects. Clinically implementable pharmacokinetic/-dynamic models adjusted for relevant pharmacogenetics could improve individual dosing. Prospective trials of TDM-based treatments, including both children and adults, are needed.

BCR/ABL-Positive Chronic Myeloid Leukemia in Children: Current Treatment Approach

PURPOSE OF REVIEW

The purpose of this review is to summarize the most updated treatment recommendations for pediatric CML, and to discuss current areas of investigation.

RECENT FINDINGS

There is new phase 1 data to support the safety of the non-ATP competitive tyrosine kinase inhibitor (TKI) asciminib in the pediatric cohort. Ongoing studies are investigating the role of treatment-free remission in children. Chronic phase CML in children is managed with lifelong TKI therapy; however, evidence of deeper remissions sustained with second-generation TKIs may permit shorter treatment courses. Use of more specific TKIs may mitigate some of the side effects specific to the pediatric cohort. Children with advanced phase CML should achieve a complete hematologic remission with use of a second-generation TKI prior to transplant to achieve the best outcome.

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.

Front-Line Tyrosine Kinase Inhibitors in Pediatric Chronic Myeloid Leukemia: A Study on Efficacy and Safety

We conducted a retrospective study on 51 pediatric patients with newly diagnosed chronic myeloid leukemia chronic phase or accelerated phase. The patients were classified into the IMA group (N = 33), treated with imatinib, and the DSA group (N = 18), treated with dasatinib, as front-line tyrosine kinase inhibitors (TKIs). At 12 months, the rates of complete cytogenetic response were similar between the IMA group (92.3%) and DSA group (100%) (p = 0.305). However, the rate of early molecular response was higher in the DSA group than in the IMA group (100.0% vs. 80.0%, p = 0.043). By 12 and 24 months, the DSA group showed faster and higher cumulative rates of both major (DSA group: 72.2% and 100%, respectively; IMA group: 41.2% and 68.7%, respectively; p = 0.002) and deep molecular responses (DSA group: 26.0% and 43.6%, respectively; IMA group: 13.8% and 17.5%, respectively; p = 0.004). Both TKIs were well tolerated. Although the height standard deviation scores decreased in both groups, the height decline was greater in the DSA group between one and two years from the start of TKI therapy. In this study, dasatinib achieved faster and higher molecular responses with an acceptable safety profile. Further follow-up is necessary to assess the long-term outcomes of TKI treatment in children.

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.

Patient-reported long-term outcome following allogeneic hematopoietic stem cell transplantation in pediatric chronic myeloid leukemia

Background

Pediatric CML is very rare. Before the introduction of tyrosine kinase inhibitors (TKIs), allogeneic hematopoietic stem cell transplantation (HSCT) from a donor -if available- was the standard cure attempt. Data on the long-term outcome and health-related quality of life (HRQOL) in former pediatric CML patients undergoing HSCT are lacking.

Study question

We investigated long-term survivors' self-reporting to a questionnaire sent out to patients formerly enrolled in pediatric CML-HSCT trials.

Methods

Individuals with CML transplanted at age <18 years were identified from the German Childhood Cancer Registry database. Long-term survivors received a questionnaire based on the SF-36 and FACT-BMT asking them to self-report HRQOL issues. (Ethical vote #541_20 B, Medical Faculty, University of Erlangen-Nürnberg).

Results

111/171 (64.9%) individuals survived HSCT long-term and 86/111 (77.5%) fulfilled all inclusion criteria and received the questionnaire. 37/86 (43%) participants (24 female, 13 male, median age at HSCT 12 years [range 2-18], median age at the time of the survey 29 years [range 18-43]) responded after a median follow-up period of 19 years (range 4-27) after HSCT. 10/37 (27%) participants underwent no regular medical follow-up examinations. Self-reported symptoms like chronic graft-versus-host disease (cGvHD)-associated organ impairments and conditioning regimen consequences could causatively not sharply be separated in each case. Complains comprised hypothyroidism (N=11, 30%), infertility (N=9, 24%), lung problems, dry eyes (each N=7, 19%), skin alterations (N=6, 17%), hair problems (N=4, 11%), and sexual dysfunction (N=3, 9%). 10 (27%) participants experienced 13 CML relapses after a median interval from HSCT of 31 months (range 2-93). Only one patient underwent 2nd SCT after failure of relapse treatment with TKIs. Six secondary malignancies (dysplastic melanocytic nevus and ALL, basal cell carcinoma (N=2), rhabdomyosarcoma, and thyroid carcinoma developed in 5 (13%) participants. As assessed by the SF-36 questionnaire, impaired physical health was mainly associated with cGvHD. The mental component summary score showed that also participants without cGvHD scored significantly lower than the general population. When assessed by the FACT-BMT, participants with cGvHD scored significantly lower while participants without cGvHD scored even 5 points higher than the data from controls. 18 (49%) participants considered the sequelae of HSCT an obstacle to education. Out of the total cohort, N=20 (54%), N=7 (19%), N=5 (14%), and N=4 (11%) participants worked full time, part-time, were unemployed, or had not yet finalized their education, respectively. 20 (54%) participants lived as singles, 8 (22%) lived in a partnership, 6 (16%) were married, and 3 (8%) had been divorced. Four (11%) participants reported a total number of 7 children.

Conclusion

This first assessment of HRQOL in former pediatric patients with CML surviving HSCT for more than two decades demonstrates self-reported satisfactory well-being only in the absence of cGvHD. Research-based on self-reported outcomes sheds light on former patients' perspectives and provides an additional layer of valuable knowledge for pediatric and adult hematologists. Regular follow-up examinations are mandatory helping to avoid that late secondary neoplasias, CML-relapse, and disorders forming the broad range of possible long-term consequences of HSCT are not detected too late.

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.

Management of Chronic Myeloid Leukemia in Children and Young Adults

Purpose of Review

Due to lack of pediatric-specific data, the management of chronic myeloid leukemia (CML) in pediatric, adolescents, and young adults is guided by adult CML evidence-based recommendations. Pediatric CML presents differently than adult CML and is often a more aggressive disease with different biological and host factors, yet there is sparse literature on how to address those differences.

Recent Findings

Over the past two decades, tyrosine kinase inhibitors (TKIs) have changed the way CML is treated. There are currently three FDA-approved TKIs (imatinib, dasatinib, and nilotinib) for pediatric patients. When choosing which TKI to begin treatment with, there are many factors that should be considered on a case-to-case basis to obtain optimal outcomes. The safety profiles for long-term TKI use in pediatrics require further study. Unlike adults, children are still actively growing during TKI use, and the effect on development can be detrimental. TKI therapy is not recommended during pregnancy with variable but significant risk of fetal abnormalities and miscarriage, warranting counseling for young female patients prior to beginning TKIs. Attempts for treatment-free remission (TFR) by planned TKI cessation in eligible adult patients in deep and sustained molecular remission are now done as a standard of practice. However, data is sparse in the pediatric population. There is currently an ongoing Children’s Oncology Group (COG) study to determine the feasibility of TFR as a treatment goal.

Summary

Further research and additional pediatric trials are needed to characterize the unique aspects of CML in children and adolescents and optimize outcomes.

Outcome prediction of chronic myeloid leukemia (CML) in children

We evaluated the feasibility of existing risk assessment tools for chronic myeloid leukemia (CML) in children. Fifty-five patients with newly diagnosed CML between 1996 and 2019 were included. Forty-nine patients presented in chronic phase, thirty-six of whom were treated with upfront tyrosine kinase inhibitor (CP-TKI group); one presented in accelerated phase and four in blastic phase. Treatment, survival, responses, and tolerance were evaluated. All patients in the CP-TKI group received imatinib as their first TKI treatment. The 10-year overall survival (OS), progression-free survival (PFS), and event-free survival (EFS) of TKI-treated group was 97%, 91.4%, and 72.3%, respectively. At 60 months, the rates of major molecular response were 81.2% and deep molecular response was 67.5%. The EUTOS long-term survival (ELTS) risk grouping did not predict OS, PFS, or EFS. The IMAFAIL risk groups were correlated with the risk of imatinib failure. Further studies are required to modify the existing risk assessment tools for children.

Endocrine Late Effects in Childhood Cancer Survivors

Simple Summary

Recent advances in cancer treatment have led to improved survival, with an exponential increase in sequelae among survivors. Around 50% of survivors will experience at least one hormonal disorder, with radiotherapy, hematopoietic stem cell transplantation, and alkylating chemotherapy being the most frequently related. Therefore, lifelong monitoring of childhood cancer survivors at risk is paramount. With this review, we describe in detail the most prevalent endocrine sequelae, considering new approaches such as proton beam therapy and immune-related endocrinopathies with the advent of precision oncology treatment. We hope to encourage oncologists and endocrinologists to develop early detection guidelines that minimize sequelae and have a positive impact on their quality of life.

Abstract

Childhood cancer management has improved considerably over the years, leading to a significant improvement in survival of up to 80%. However, childhood cancer survivors are at the highest risk of developing sequelae resulting from treatment, with endocrine complications being frequently observed among survivors. Multiple predisposing factors for endocrine sequelae have been identified, including age at diagnosis, treatment received, radiation, tumor type, and genetic polymorphisms, which could explain the individual predisposition to develop drug toxicity. Novel agents targeting tumor growth and immune checkpoint inhibitors have recently become the cornerstone for the treatment of different cancers, triggering a myriad of immune-related endocrinopathies. Endocrine sequelae of cancer therapy will have an impact on not only childhood but also on the survival and quality of life of these highly complex patients. Therefore, lifelong monitoring of childhood cancer survivors at risk of endocrine diseases is paramount. Encouraging oncologists and endocrinologists to develop new follow-up and early detection guidelines that minimize sequelae among these patients has become a priority, promoting integration between pediatric and adult units since many sequelae may manifest only after years to decades of follow-up.

Safety of growth hormone replacement in survivors of cancer and intracranial and pituitary tumours: a consensus statement

Growth hormone (GH) has been used for over 35 years, and its safety and efficacy has been studied extensively. Experimental studies showing the permissive role of GH/insulin-like growth factor 1 (IGF-I) in carcinogenesis have raised concerns regarding the safety of GH replacement in children and adults who have received treatment for cancer and those with intracranial and pituitary tumours. A consensus statement was produced to guide decision-making on GH replacement in children and adult survivors of cancer, in those treated for intracranial and pituitary tumours and in patients with increased cancer risk. With the support of the European Society of Endocrinology, the Growth Hormone Research Society convened a Workshop, where 55 international key opinion leaders representing 10 professional societies were invited to participate. This consensus statement utilized: (1) a critical review paper produced before the Workshop, (2) five plenary talks, (3) evidence-based comments from four breakout groups, and (4) discussions during report-back sessions. Current evidence reviewed from the proceedings from the Workshop does not support an association between GH replacement and primary tumour or cancer recurrence. The effect of GH replacement on secondary neoplasia risk is minor compared to host- and tumour treatment-related factors. There is no evidence for an association between GH replacement and increased mortality from cancer amongst GH-deficient childhood cancer survivors. Patients with pituitary tumour or craniopharyngioma remnants receiving GH replacement do not need to be treated or monitored differently than those not receiving GH. GH replacement might be considered in GH-deficient adult cancer survivors in remission after careful individual risk/benefit analysis. In children with cancer predisposition syndromes, GH treatment is generally contraindicated but may be considered cautiously in select patients.

Discontinuation of tyrosine kinase inhibitors based on BCR-ABL1 monitoring by digital droplet PCR in pediatric chronic myeloid leukemia

Lifelong treatment of pediatric chronic myeloid leukemia (CML) patients with tyrosine kinase inhibitors (TKIs) can affect their growth and development. For these reasons, clinical trials have explored the feasibility of TKI discontinuation in children with a sufficient TKI response. We evaluated the analytical performance of digital droplet PCR (ddPCR) to quantify BCR-ABL1 and compared the results with reverse transcription quantitative polymerase chain reaction (RT-qPCR). We further investigated whether ddPCR could be used to determine TKI discontinuation in a clinical setting. Performance of ddPCR was evaluated using standard materials for BCR-ABL1, and a total of 197 clinical samples from 45 pediatric CML patients was included for comparison with RT-qPCR. ddPCR showed excellent analytical sensitivity with 0.001% international scale (IS) and linearity with R ² > 0.99 in log scale. BCR-ABL1 % IS results correlated well with those of RT-qPCR (R ² = 0.9435), however, they showed a moderate strength for agreement with a Cohen's kappa of 0.41 due to higher sensitivity of ddPCR. Among 45 pediatric CML patients, 42 were treated with first-line TKIs including imatinib (n = 27, 64%) and dasatinib (n = 12, 29%), and three patients that were started with imatinib were switched to dasatinib. When we evaluated whether follow-up samples fulfilled ABL1 copies ≥ 10,000 required for deep molecular response (DMR), all samples were acceptable by ddPCR, whereas 18% by RT-qPCR did not reached acceptable ABL1 copies. Moreover, 52 and 13% reached ABL1 copies ≥ 32,000 required for MR4.5 by ddPCR and RT-qPCR, respectively. Seven patients discontinued TKI and the median TKI treatment duration was 73 months prior to discontinuation. Prior to discontinuation, the median duration of sustained undetected BCR-ABL1 was 60 months. Two patients experienced loss of major MR (MMR) during follow-up and restarted dasatinib 5 months after discontinuation. They achieved MMR again and maintained better than DMR afterward. Results from those patients demonstrated that RT-qPCR did not match the need for adequate ABL1 copies for MR4.5 while majority of ddPCR could. Therefore, ddPCR was technically more acceptable to decide and monitor pediatric CML patients before and after TKI discontinuation.

Targeted cancer treatment and fertility: effect of immunotherapy and small molecule inhibitors on female reproduction

Targeted cancer therapy is rapidly evolving the landscape of personalized health care. Novel approaches to selectively impeding tumour growth carry significant potential to improve survival outcomes, particularly for reproductive-aged patients harbouring treatment refractory disease. Current agents fall within two classes: immunotherapy and small molecule inhibitors. These are collectively divided into the following subclasses: monoclonal antibodies; immunomodulators; adoptive cell therapy; treatment vaccines; kinase inhibitors; proteasome inhibitors; metalloproteinase and heat shock protein inhibitors; and promoters of apoptosis. The short- and long-term effects of these treatments on the female reproductive system are not well understood. As a result, clinicians are rendered unable to appropriately counsel women on downstream effects to their fertility. Data-driven consensus recommendations are desperately needed. This review aims to characterize the effect of targeted cancer therapy on the female hypothalamic-pituitary-ovary axis, direct ovarian function and conception.

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.

Rationale for the use of tyrosine kinase inhibitors in the treatment of paediatric desmoid-type fibromatosis

In children with desmoid-type fibromatosis (DTF) in whom disease progression occurs after an initial watch-and-wait strategy, prolonged low-dose chemotherapy using vinblastine and methotrexate (VBL-MTX) is currently the standard of care. These conventional drugs have been prospectively evaluated but their efficacy and safety profiles are limited, and alternative therapeutic options are therefore essential. Based on the results of clinical trials, the use of tyrosine kinase inhibitors (TKIs) in the treatment of DTF is currently considered only in adult patients. TKIs such as imatinib show superior therapeutic efficacy to VBL-MTX and tolerable short-term side effects for the treatment of adult DFT, supporting the concept of the use of TKIs for the treatment of paediatric DFT. Moreover, new-generation TKIs, such as pazopanib and sorafenib, have shown improved therapeutic efficacy compared to imatinib in adult non-comparative studies. A tolerable safety profile of TKI therapy in children with disease entities other than DTF, such as leukaemia, has been reported. However, the efficacy and, in particular, the long-term safety of TKIs, including childhood-specific aspects such as growth and fertility, for the treatment of children with DTF should be investigated prospectively, as DFT therapy requires long-term drug exposure.

Tyrosine Kinase Inhibitors and Beyond for Chronic Myeloid Leukemia in Children

Chronic myeloid leukemia (CML) is rare in children but presents a unique challenge as recent drug innovations have turned CML into a chronic disease with implications for treatment into adulthood. With the approval of newer-generation tyrosine kinase inhibitors (TKIs) in addition to imatinib, providers have more options for the treatment of chronic-phase CML (CML-CP) in children. The second-generation TKIs approved for use in children, nilotinib and dasatinib, have higher response rates than first-generation imatinib; however, overall survival rates appear to be the same. Even more options may soon become available with ongoing investigations into the use of bosutinib and ponatinib and other new agents in children. Possible long-term side effects of TKIs, including growth failure, should be carefully acknowledged by the treating provider. Although these known associations may not preclude treatment, providers should be aware of them to guide their management of pediatric patients with CML being treated long term with TKI therapy. Treatment-free remission is a desired goal for pediatric patients and providers alike, but current recommendations are for attempts at achieving this to be restricted to clinical study settings.

Fertility considerations in targeted biologic therapy with tyrosine kinase inhibitors: a review

PURPOSE

To review the impact of tyrosine kinase inhibitors (TKIs) on fertility in men and women, embryo development, and early pregnancy, and discuss considerations for fertility preservation in patients taking TKIs.

METHODS

A comprehensive literature search using the PubMed database was performed through February 2021 to evaluate the current literature on imatinib, nilotinib, dasatinib, and bosutinib as it relates to fertility and reproduction. Published case series were analyzed for pregnancy outcomes.

RESULTS

TKIs adversely affect oocyte and sperm maturation, gonadal function, and overall fertility potential in a self-limited manner. There are insufficient studies regarding long-term consequences on fertility after discontinuation of TKIs. A total of 396 women and 236 men were on a first- or second-generation TKI at the time of conception. Of the women with detailed pregnancy and delivery outcomes (n = 361), 51% (186/361) resulted in a term birth of a normal infant, 4.3% (16/361) of pregnancies had a pregnancy complication, and 5% (20/361) of pregnancies resulted in the live birth of an infant with a congenital anomaly. About 22% of pregnant women (87/396) elected to undergo a termination of pregnancy, while 16% (63/396) of pregnancies ended in a spontaneous abortion. In contrast, of the 236 men, 87% conceived pregnancies which resulted in term deliveries of normal infants. Elective terminations, miscarriage rate, pregnancy complication rate, and incidence of a congenital malformation were all less than those seen in females (4%, 3%, 2%, and 2.5%, respectively).

CONCLUSION

Women should be advised to avoid conception while taking a TKI. Women on TKIs who are considering pregnancy should be encouraged to plan the pregnancy to minimize inadvertent first trimester exposure. In women who conceive while taking TKIs, the serious risk of relapse due to discontinuation of TKI should be balanced against the potential risks to the fetus. The risk of teratogenicity to a fathered pregnancy with TKI use is considerably lower. Fertility preservation for a woman taking a TKI can be considered to plan a pregnancy with a minimal TKI-free period. With careful monitoring, providers may consider a TKI washout period followed by controlled ovarian stimulation to cryopreserve oocytes or embryos, with a plan to resume TKIs until ready to conceive or to transfer an embryo to achieve pregnancy quickly. Fertility preservation is also indicated if a patient on TKI is requiring a gonadotoxic therapy or reproductive surgery impacting fertility.

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.

A case of ovarian stimulation for fertility preservation in a patient with Philadelphia chromosome-positive acute lymphoblastic leukemia after treatment with dasatinib

Tyrosine kinase inhibitors (TKIs) are effective for treating Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL). However, the use of TKIs may decrease the number of collected oocytes during fertility preservation procedures. We report the case of a 19-year-old patient with Ph+ALL for whom 21 oocytes were frozen after controlled ovarian stimulation was initiated 2 days after the completion of 28 days of remission induction therapy with dasatinib. After collecting the oocytes, consolidation therapy was initiated immediately, and a hematopoietic stem cell transplant from her younger brother was scheduled. It is believed that a 2-day withdrawal period is sufficient for fertility preservation or that the effect of dasatinib on the number of oocytes obtained is minimal.

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。

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.

Vaccination With Live Attenuated Vaccines in Four Children With Chronic Myeloid Leukemia While on Imatinib Treatment

Chronic myeloid leukemia (CML) in childhood and adolescence is a rare malignancy that can successfully be treated with the tyrosine kinase inhibitor (TKI) imatinib. According to the current experience, treatment is necessary for years and, in the majority of cases, a lifelong approach is required to control the malignant disease. To what extent imatinib causes immunosuppression in different age cohorts is a controversial discussion. According to general medical recommendations, live vaccines are contraindicated in individuals treated with imatinib. However, a recent increase in the number of globally reported cases of measles has been observed and continues to rise. Due to the high contagiousness of the virus, near-perfect vaccination coverage (herd immunity of 93 to 95%) is required to effectively protect against measles resurgence-a scenario that is not realistic in many countries. When four teenagers with CML (median age 13 years, range 12-15) who were enrolled into pediatric trial CML-paed II while on imatinib treatment (median treatment duration 36 months, range 11-84) were identified without protective measles and/or varicella titers, we carefully balanced the risks of a live vaccination under immunosuppressive TKI medication against the benefit of being protected. The patients underwent live vaccination with the live attenuated vaccines M-M-RVAX Pro® and Varivax® simultaneously (Patient #1), Priorix® and Varilix® consecutively (Patient #2), and Priorix® (Patients #3 and #4). While the first three patients were vaccinated while receiving TKI therapy, treatment with imatinib was interrupted in patient #4 for 1 week prior and 2 weeks after vaccination. Patients #1 and #3 reacted with stable long-term seroconversion. In Patient #2, serum titer conversion against measles and varicella could not be demonstrated and thus revaccination with Priorix® and Varilix® was performed 3 years later. However, protective titers did not develop or were lost again. Patient #4 also lost protective titers against measles when assessed 10 months after vaccination, but revaccination resulted in stable seroprotective titers over 12 months after the last vaccination during ongoing imatinib treatment. We conclude that in all patients, the safety of live vaccines could be documented, as no acute or late adverse events were observed. However, in line with observations that memory B-cells are lost under exposure to imatinib, revaccination may become necessary (two out of four patients in this small series lost their seroprotection). Considering that the number of cases is very small, we also suggest some criteria for decision-making regarding live vaccinations of CML patients treated with imatinib.

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.

Pharmacokinetics of Nilotinib in Pediatric Patients with Philadelphia Chromosome-Positive Chronic Myeloid Leukemia or Acute Lymphoblastic Leukemia

PURPOSE

We investigated nilotinib exposure in pediatric patients with chronic myeloid leukemia (CML) or Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) resistant to, relapsed on, refractory to, or intolerant of previous treatment.

PATIENTS AND METHODS

Fifteen patients (aged 1-<18 years) with CML resistant to or intolerant of imatinib and/or dasatinib (n = 11) or Ph+ ALL relapsed on or refractory to standard therapy (n = 4) enrolled in this phase I study. Nilotinib (230 mg/m2 twice daily; equivalent to the adult 400-mg twice-daily dose) was administered orally in 12 or 24 cycles of 28 days. The primary objective was to characterize the pharmacokinetics of nilotinib in pediatric patients.

RESULTS

The area under the concentration-time curve at steady state was slightly lower in pediatric patients versus adults (14,751.4 vs. 17,102.9 ng/h/mL); the geometric mean ratio (GMR; pediatric:adult) was 0.86 [90% confidence interval (CI), 0.70-1.06]. Body surface area-adjusted systemic clearance was slightly higher in pediatric versus adult patients (GMR, 1.30; 90% CI, 1.04-1.62). Nilotinib was generally well tolerated. The most common adverse events were headache, vomiting, increased blood bilirubin, and rash. Three patients with CML achieved major molecular response, and three with Ph+ ALL achieved complete remission.

CONCLUSIONS

Nilotinib 230 mg/m2 twice daily in pediatric patients provided a pharmacokinetics and safety profile comparable with the adult reference dose; clinical activity was demonstrated in both CML and Ph+ ALL. This dose is recommended for further evaluation in pediatric patients. The safety profile was consistent with that in adults.

Experience with ponatinib in paediatric patients with leukaemia

Ponatinib has proven to be effective in adults with Philadelphia chromosome-positive leukaemias, but data in paediatrics are scarce. Among paediatric patients with chronic myeloid leukaemia (n = 9) or acute lymphoblastic leukaemia (n = 12) treated with varying doses of ponatinib in 13 centres, 71% showed a decrease in disease burden after a median of three months. Ponatinib was well tolerated, with grade 3 toxicities occurring in 29% of patients. Toxicities were similar to those reported in adults, with the exception of arterial thrombotic events, which were not observed. Ponatinib has a favourable safety profile in this paediatric cohort, but dose-finding studies are needed.

Pharmacology of tyrosine kinase inhibitors in chronic myeloid leukemia; a clinician's perspective

OBJECTIVE

In this review, we have summarized the pharmacokinetics, pharmacodynamics and adverse effects of imatinib, dasatinib, nilotinib, bosutinib, ponatinib and radotinib with focus on pharmacogenomic studies with clinical end points. We have discussed the key phase 3 trials of tyrosine kinase inhibitors (TKI) comparing with each other, treatment free remission (TFR) and selection of TKI. Upcoming concepts and related trials in the management of chronic myeloid leukemia (CML) along with future directions have been touched upon.

EVIDENCE ACQUISITION

PubMed, Embase, Google, Cochrane library and Medline were searched to identify relevant literature for the review. Clinicaltrial.gov was searched for upcoming data and trials.

RESULTS

There are lot of gap in pharmacokinetics and pharmacodynamics of TKI. Imatinib appears to be the safest TKI. Newer TKI's achieve better achievement of therapeutic milestones, deeper molecular response and less chances of progression of CML compared to imatinib. Newer TKI appears to be better choice for achieving TFR. When the objective is survival, imatinib is still the TKI of choice. Primary prophylaxis with antiplatelet drugs for TKI having cardiovascular and thromboembolic side effects should be considered.

CONCLUSION

Pharmacogenetic data of TKI is still immature to guide in therapeutic decision making in clinical practice. There is need for further research in pharmacology and pharmacogenomics of newer TKI's. Randomized controlled trials are required to decide the optimum TKI for TFR. Safe and effective TKI for targeting T315I mutation, CML accelerated phase and blast crisis are an active area of 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.

Childhood Cancer Treatments and Associated Endocrine Late Effects: A Concise Guide for the Pediatric Endocrinologist

Endocrine complications are frequently observed in childhood cancer survivors (CCS); in many instances, these complications develop months to years after the completion of cancer therapy. The estimated prevalence of endocrine late effects is 50% among CCS; the main risk factors are external beam radiation that includes key endocrine organs (the hypothalamus/pituitary, thyroid and gonads) and/or alkylating agents. Novel agents targeting tumor growth have increased the options available to a small number of patients albeit with the need for treatment over long periods of time. Some of these agents, such as certain tyrosine kinase inhibitors and immune system modulators have been shown to cause permanent endocrine deficits. This chapter offers a brief summary of the conventional treatment strategies for the most common cancers of childhood and a brief overview of the endocrine late effects most commonly associated with these exposures. The impact of targeted therapies on the endocrine system will also be discussed. The aim of this chapter is to provide basic guidance to the consulting pediatric endocrinologist in preparation for the clinical encounter with a CCS. A more detailed discussion of the management of specific endocrine late effects can be found in the other chapters in this series.

Evaluating the endometabolic and bone health effects of Tyrosine Kinase Inhibitors in Chronic Myeloid Leukaemia: a systematic review protocol

INTRODUCTION

Chronic Myeloid Leukaemia (CML) constitutes 15% of new adult leukaemia cases as well as 2%-3% of leukaemia in children under 15% and 9% of leukaemias in adolescents 15-19 years of age annually. The introduction of Tyrosine Kinase Inhibitors (TKI) therapy has dramatically improved survival in these patients, yet the off-target effects of this treatment may have long-term health impacts on CML survivors. The risk of adverse health outcomes is especially important in children, where TKI exposure may occur during critical windows of growth and puberty, and patients require treatment for prolonged periods of time. The aim of this systematic review protocol is to report on the methods used to conduct a systematic review to investigate the endometabolic and bone health effects of TKI therapy in CML.

METHODS AND ANALYSIS

Searches will be conducted in the Cochrane Central Register of Controlled Trials, EMBASE and MEDLINE from inception on August 1st, 2019. Searches may be updated while performing the systematic review to ensure new evidence is included if applicable. Grey literature search will include ClinicalTrials.gov and ProQuest Dissertations and Theses A&I. We will perform a meta-analysis if there are at least two studies reporting similar populations, interventions, methods and tracking the same outcome measures. The studies should also have similar age and sex distributions.

ETHICS AND DISSEMINATION

As this is a systematic review protocol, it does not include patient data; therefore, Research Ethics Board approval is not indicated. The systematic review will be published in a peer-reviewed journal and presented at international conferences.

PROSPERO REGISTRATION NUMBER

CRD42018091175.

Management of chronic myeloid leukemia in children and adolescents: Recommendations from the Children's Oncology Group CML Working Group

Chronic myeloid leukemia (CML) accounts for 2-3% of leukemias in children under 15 and 9% in adolescents aged 15-19. The diagnosis and management of CML in children, adolescents, and young adults have several differences compared to that in adults. This review outlines the diagnosis and management of the underlying disease as well as challenges that can occur when dealing with CML in this patient population.

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.

Endocrine Consequences of Childhood Cancer Therapy and Transition Considerations

Childhood cancer survivors are at risk for chronic health conditions related to their cancer or their therapy. Of these chronic sequelae, endocrinopathies are some of the most common complications and may include thyroid disorders, reproductive and pituitary dysfunction, and metabolic syndrome. It is important for the primary care physician and endocrinologist to be aware of these possible consequences, as many of them develop months or years after the initial cancer diagnosis and therapy. They may affect adolescents and young adults during a vulnerable time, when they are ideally transitioning into a more independent role in their care and possibly preparing to transfer their health care to new providers. The purpose of this article is to summarize the endocrine complications that may occur following therapy for childhood cancer, and to briefly describe specific considerations in transitioning this population. [Pediatr Ann. 2019;48(8):e326-e332.].

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.

The Bone Phenotype and Pain Response to Pamidronate in Tyrosine Kinase Inhibitor-Treated Chronic Myelogenous Leukemia

Tyrosine kinase inhibitors (TKIs) have been linked to bone pain and linear growth attenuation in children with TKI-treated chronic myelogenous leukemia (CML). We describe the skeletal phenotype in an 11-year-old boy with chronic bone pain due to TKI-treated CML, including his response to intravenous (IV) pamidronate. This boy was diagnosed with Philadelphia chromosome-positive CML at 4 years of age. He was treated with imatinib for 3 years, followed by dasatinib for 4 years. At age 11 years, he was seen in a bone health clinic with a 4-year history of leg pains that necessitated regular nonsteroidal anti-inflammatory drugs (NSAIDS) and downward crossing of height percentiles (from the 25th to fifth). The bone volume/tissue volume Z-score was +1.6 for a trans-iliac bone biopsy specimen, with an increase in trabecular number (Z-score, +3.1). Bone formation and resorption parameters on trabecular surfaces were within normal limits. Tibia volumetric bone mineral density (BMD) and bone geometry were normal by peripheral quantitative computed tomography, areal BMD Z-scores were average or above average at multiple skeletal sites by dual-energy x-ray absorptiometry, and tibia length Z-score was reduced (−2.3). Growth- and bone-related biochemical studies were unremarkable except a low serum alkaline phosphatase level. His bone pain resolved completely after 9 months of low-dose IV pamidronate. An increase in trans-iliac trabecular number and shortened tibia were the main skeletal features in this patient. Short-term IV pamidronate was effective for mitigating bone pain, allowing this boy to continue receiving dasatinib without the need for chronic NSAID therapy.

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.

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.

Factors influencing risk-based care of the childhood cancer survivor in the 21st century

The population of adult survivors of childhood cancer continues to grow as survival rates improve. Although it is well established that these survivors experience various complications and comorbidities related to their malignancy and treatment, this risk is modified by many factors that are not directly linked to their cancer history. Research evaluating the influence of patient-specific demographic and genetic factors, premorbid and comorbid conditions, health behaviors, and aging has identified additional risk factors that influence cancer treatment-related toxicity and possible targets for intervention in this population. Furthermore, although current long-term follow-up guidelines comprehensively address specific therapy-related risks and provide screening recommendations, the risk profile of the population continues to evolve with ongoing modification of treatment strategies and the emergence of novel therapeutics. To address the multifactorial modifiers of cancer treatment-related health risk and evolving treatment approaches, a patient-centered and risk-adapted approach to care that often requires a multidisciplinary team approach, including medical and behavioral providers, is necessary for this population. CA Cancer J Clin 2018;68:133-152. © 2018 American Cancer Society.

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.

T-cell-rich HLA-haploidentical hematopoietic stem cell transplantation for relapsed/refractory pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia without posttransplant tyrosine kinase inhibitor therapy

Intensive chemotherapy with tyrosine kinase inhibitor (TKI) improves the prognosis of patients with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-ALL). However, the prognosis of cases of relapsed or refractory Ph-ALL remains poor. Here, we aimed to assess the efficacy of T-cell-rich HLA-haploidentical hematopoietic stem cell transplantation (TCR-haplo-HSCT) in eight patients with relapsed or refractory pediatric Ph-ALL. Transplant-related mortality was observed in two patients. All patients discontinued TKI after receiving TCR-haplo-HSCT. The 3-year probability of overall survival and event-free survival was 75.0 and 62.5%, respectively. These results indicate the efficacy of TCR-haplo-HSCT for relapsed/refractory pediatric Ph-ALL.