Study Cohort:
As per the above-mentioned eligibility criteria the study cohort comprised of children newly diagnosed with ALL during the period January 2002 until December 2018 aged 1 to 14 years, either refractory to first-line treatment or experiencing relapse at medullary and / or extra-medullary site. The study cohort included patients who received treatment for relapse during the study defined period i.e. January 2002 to December 2018 at King Faisal Specialist Hospital & Research Centre (KFSH&RC), Jeddah, Saudi Arabia.
The study commenced after obtained regulatory approvals from the Institutional Review Board (IRB) utilizing the IRB-approved study Case Report Form (CRF) to abstract data from paper-based and electronic medical charts of the identified study cohort. Date was collected and managed utilizing the REDCap electronic data capture softed hosted by KFSH&RC, Jeddah. The overall conduct of the study was in compliance in Good Clinical Practice (GCP) guidelines and no personal identifiable information ever collected throughout the conduct of the study, while access to study data restricted to the research team through password-controlled users.