Real-world Experience of Imatinib in Pediatric Chronic Phase Chronic Myeloid Leukemia: A Single-center Experience From India

Sex Bias in Treatment Abandonment of Childhood Cancer in India

OBJECTIVES

To explore the magnitude of sex bias and determinants of treatment abandonment (TA) in childhood cancer in India.

METHODS

Individual data of children (0-19 y) registered between January 1, 2017 and July 31, 2022, was compiled. TA was defined as defaulting curative intent treatment ≥4 wk. Defaulting treatment irrespective of intent ≥4 wk was defined as Treatment Default (TD). The primary outcome was the proportion of male-to-female children with TA. Secondary outcomes included the proportion of male-to-female children with upfront TA, TA at relapse, TD, TD-p (TD only in the palliative setting). The impact of clinico-demographic factors on TA was analysed using multivariable regression and propensity score matching (PSM).

RESULTS

Three thousand two hundred eighty four patients were analysed. The overall male-to-female ratio (MFR) was 2.08 (95% CI 1.94-2.24). Of 2906 patients treated with curative intent, 415 (14·3%) abandoned treatment. TA was higher in females than males (16·4% vs. 13·3%; p = 0·022) with adjusted MFR of 0·81 (0·66-0·98). The adjusted MFR of TA for treatment-naïve and relapsed patients and TD were 0·73 (0·59-0·91), 1·13 (0·65-1·96) and 0·84 (0·71-1·00) respectively. Sex independently predicted TA on multivariable analysis. However, on PSM analysis including socio-economic variables, lower maternal education predicted higher TA in children with cancer (10·1% vs. 6%, p = 0·015).

CONCLUSIONS

Child sex predicted TA in childhood cancer in India with more females abandoning treatment. Maternal education is a more crucial factor predicting TA over child sex, when socio-economic factors were considered. Hence, policies promoting female education and gender equality may mitigate sex-based gaps in childhood cancer care.

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.

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

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

Children with chronic myeloid leukaemia treated with front-line imatinib have a slower molecular response and comparable survival compared with adults: a multicenter experience in Taiwan

BACKGROUND

The direct comparison of molecular responses of front-line imatinib (IM) monitored at the same laboratory between children and adults with chronic phase (CP) of chronic myeloid leukaemia (CML) had not been reported. In this multicenter study, we compared the landmark molecular responses and outcomes of paediatric and adult CML-CP cohorts treated with front-line IM in whom the BCR::ABL1 transcript levels were monitored at the same accredited laboratory in Taiwan.

METHODS

Between June 2004 and July 2020, 55 newly diagnosed paediatric and 782 adult CML-CP patients, with molecular diagnosis and monitoring at the same reference laboratory in Taiwan, were enrolled. The criteria of 2020 European LeukemiaNet were applied to evaluate the molecular responses.

RESULTS

By year 5, the cumulative incidences of IS <1%, MMR, MR4.0 and MR4.5 of paediatric patients were all significantly lower than those of adult patients (58 vs 75%, 48 vs 66%, 25 vs 44%, 16 vs 34%, respectively). The 10-year progression-free survival (PFS) (90%) and overall survival (OS) (94%) of paediatric patients did not differ from those (92%) of adult patients.

CONCLUSIONS

We demonstrated the paediatric cohort had slower molecular responses to front-line IM and similar outcomes in 10-year PFS and OS in real-world practice.

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.

Long-Term Outcome of Philadelphia Chromosome Positive Leukemia From Eastern Indian Subcontinent: An Experience in the Era of Tyrosine Kinase Inhibitor (TKI) Therapy

INTRODUCTION

Philadelphia chromosome (Ph) marks a group of leukemia with almost all cases of chronic myeloid leukemia (CML), a subset of acute lymphoid leukemia (ALL) and rare cases of acute myeloid leukemia (AML). In the era of precision medicine, such cases are successfully managed with tyrosine kinase inhibitor (TKI) drugs. This study examined the features and long-term outcome of Ph+ve cases from a tertiary cancer care center from Eastern Indian subcontinent.

MATERIALS AND METHODS

Reviewing retrospective case-records registered between 2005 and 2015, cases of CML and ALL were documented under Ph+ve category; while no instance of Ph+ve AML was found.

RESULTS

In CML cohort, adult and juvenile incidences were 95.2% and 4.8% respectively; in ALL cohort, the same was found for 66.67% and 33.33% cases. Among the CML cases, 10-year overall survival (OS) and progression-free survival (PFS) were significantly affected upon the phase of disease at time of detection. Furthermore, both OS and PFS significantly dropped whenever non-TKI-based treatment was applied prior to TKI-commencement. Long-term (10-year) sensitivity to 1st generation TKI, imatinib, was noted 88.51% and 83.33% for adult and juvenile CML cohorts, respectively. For Ph+ ALL cohort, the OS was benefitted upon combinatorial TKI and chemotherapy. However, large fractions of affected individual from CML as well as ALL cohorts were found to discontinue follow-up.

CONCLUSION

Together with differences in outcome on the basis of drug-use from onset, age (juvenile versus adult) and stage at diagnosis, our analyses bring forward the real-world scenario of Ph+ve leukemia managed with precision medicine.