# Molecularly Targeted Small Molecule Inhibitor Therapy for Pediatric Acute Lymphoblastic Leukemia: A Comprehensive Review of Clinical Trials

## TL;DR

This paper reviews clinical trials of targeted small molecule inhibitors for treating high-risk pediatric acute lymphoblastic leukemia, aiming to improve outcomes with less toxicity than traditional chemotherapy.

## Contribution

The paper provides a comprehensive review of clinical trials for molecularly targeted therapies in pediatric ALL, highlighting progress and future directions in precision medicine.

## Key findings

- Molecularly targeted therapies offer potential for improved outcomes in high-risk pediatric ALL.
- Clinical trials have refined treatment strategies using genomic profiling and precision medicine.
- Targeted therapies are being optimized alongside immunotherapies to reduce chemotherapy reliance.

## Abstract

Acute lymphoblastic leukemia (ALL) is the most frequent cancer of childhood. Although most children are cured with modern frontline chemoimmunotherapy regimens, those with high-risk genetics and/or relapsed/refractory diseases still face poor outcomes. There is a growing need for more precise and less toxic treatment options than traditional chemotherapy. This comprehensive review focuses upon the investigation of biologically relevant small molecule inhibitors for genetic subtypes of childhood B-ALL or T-ALL. We search a large international clinical trial database (clinicaltrials.gov) to identify studies that tested molecularly targeted drugs in children with ALL. By reviewing the results of all completed trials and presenting an overview of ongoing and upcoming studies, we aim to provide a clear picture of how these therapies have been developed so far and discuss the current direction of precision medicine in pediatric ALL.

In the past decades, significant advancements in the biological and genetic characterization of acute leukemias and optimization of risk-adapted multi-agent treatment protocols have dramatically improved cure rates and quality of life for children with acute lymphoblastic leukemia (ALL). Despite these optimal results, patients with relapsed or chemotherapy-refractory (R/R) disease or with high-risk genetic features still face unsatisfactory outcomes. Further intensification of conventional chemotherapy has reached its limits in achieving the desired efficacy without undue side effects, necessitating innovative approaches to improve cure rates while continuing to minimize the toxicities associated with chemotherapy and hematopoietic stem cell transplantation. In the era of precision medicine, two key therapeutic strategies have emerged in hemato-oncology: molecularly targeted therapies and immunotherapies. Antibody-based and cellular immunotherapies have undoubtedly reshaped the landscape of childhood ALL treatment and have significant potential to play leading roles in current and future frontline regimens; these important therapies are well delineated in recent reviews. Molecularly targeted small molecule inhibitor therapies remain a cornerstone of precision medicine, supported by recent advancements in next-generation sequencing, which have enabled the application of transcriptomic and genomic profiling data to risk stratification and therapy optimization. Clinical trials for children with ALL have been instrumental in refining therapies and improving outcomes, a paradigm that remains critical as treatment strategies become increasingly complex. This comprehensive review focuses upon molecularly targeted therapy approaches for childhood ALL and aims to summarize findings from completed clinical trials to highlight the current landscape of ongoing and upcoming trials and to provide insights into future directions for the precision-driven optimization of pediatric B-ALL and T-ALL treatment.