ALL-323: Preliminary, Updated Outcomes of the Modified, Pediatric-Based USC ALL Frontline Regimen in Hispanics and Non-Hispanics

Abstract

<h3>Context:</h3> In 2014, USC reported use of multiple doses of pegaspargase (PEG) for newly diagnosed ALL patients (7-year overall survival [OS] 51%). This is currently part of the NCCN Guidelines for frontline ALL treatment. Since then, the regimen consisting of 2 induction phases (IP) was modified, with fractionated doses of cytarabine changed to a single dose and consolidations increased to six cycles (six doses of PEG total). <h3>Objective:</h3> Outcomes since modification of the USC ALL induction regimen, with immunotherapies given when appropriate, in Hispanics <i>versus</i> non-Hispanics. <h3>Design:</h3> Retrospective chart review. <h3>Setting:</h3> Single institution, academic center/county hospital. <h3>Patients or Other Participants:</h3> Male/female patients (18–99 years) with any type of ALL diagnosed by bone-marrow/tissue biopsies during 1/2016–12/2020, treated at our institution. Patients who did not receive the modified USC ALL induction regimen with/without PEG were excluded. <h3>Interventions:</h3> Ninety-four ALL patient chart reviews. <h3>Main Outcomes Measures:</h3> OS, event-free survival (EFS) at 5 years, CR/CRi, minimal residual disease (MRD) flow; 2-sided p-value ≤0.05 was considered significant. <h3>Results:</h3> Among 63 Hispanics and 31 non-Hispanics, 67 achieved CR/CRi, 39 had MRD flow negativity after IP1; 50 CR/CRi, and 29 had MRD flow negativity after IP2. PEG was given in 59% Hispanics and 60% non-Hispanics. Salvage BiTE was given to 30 patients (Hispanic, 63%). Median follow-up for Hispanics was 17 (0.5–60) months and 21 (0.1–53) months for non-Hispanics. Median OS not-reached (NR) in both groups. Estimated OS for Hispanics at 5 years was 80% and 51% for non-Hispanics (p=0.020). Median EFS for Hispanics was 46 months and 34 months for non-Hispanics (p=0.306). <h3>Conclusions:</h3> CR/CRi and MRD flow negativity were appreciable with the median OS NR. Interestingly, a significant improvement in Hispanic OS <i>versus</i> non-Hispanics was noted. An explanation could be on how more Hispanics received salvage BiTE (63.3% of 30 patients). Also, 40% of Hispanics were able to receive stem cell transplant <i>versus</i> 33% of non-Hispanics. No significant difference in median EFS between Hispanics and non-Hispanics was noted.