# Implication of Post-Induction Minimal Residual Disease in the Management of Pediatric Acute Lymphoblastic Leukemia in a Resource-Limited Setting

## TL;DR

This study shows that measuring minimal residual disease (MRD) on Day 29 helps assess treatment response in children with leukemia, especially in areas with limited resources.

## Contribution

The study introduces Day 29 MRD as a cost-effective tool for managing pediatric ALL in resource-limited settings.

## Key findings

- 85.6% of patients had negative MRD on Day 29 and continued the same treatment regimen.
- MRD results strongly correlated with interim bone marrow assessments.
- Day 29 MRD evaluation is proposed as a single best tool for response evaluation in resource-limited areas.

## Abstract

Background: Minimal residual disease (MRD) measurement in pediatric acute lymphoblastic leukemia (ALL) is the most powerful tool for treatment response assessment.

Objective: This study aims to assess the implications of post-induction Day 29 MRD evaluation in the management of pediatric ALL within a resource-limited setting and its correlation with interim Day 8/15 bone marrow assessment.

Materials and methods: A prospective analytical study was conducted at the pediatric hematology oncology department from January 1​​​, ​2022, to December 31​​​​​, 2022. Flowcytometry-based newly diagnosed ALL patients aged 1-16 years were included. MRD assessment on Day 29 of induction and interim bone marrow evaluations on Day 8/15 were performed according to the UKALL-2019 protocol.

Results: Out of 578 patients, 407 (70.4%) were males, and 171 (29.6%) were females. The predominant age group was 5-10 years, including 324 (56.0%) patients. Flow cytometry revealed pre-B ALL in 468 (81.0%) and pre-T ALL in 110 (19.0%). High-risk patients receiving four-drug induction numbered 379 (65.6%), while 199 (34.4%) were standard risk. Interim bone marrow response was M2 in 502 (86.9%) and M3 in 73 (12.6%). Post-induction Day 29 MRD was < 0.01% (negative) in 495 (85.6%) patients who continued the same regimen, and >0.01% (positive) in 83 (14.4%) requiring treatment escalation. Among those with M3 interim marrow response, 42 (7.3%) were high-risk and MRD-positive. Induction mortality occurred in 32 (5.5%) patients, and treatment abandonment occurred in 46 (8.0%).

Conclusion: Our study has demonstrated significant induction remission response in ALL by achieving negative MRD, which correlates strongly with interim bone marrow assessment, proposing Day 29 MRD as a single best cost-effective tool for response evaluation in resource-limited settings.