Outcomes of Philadelphia Positive Acute Lymphoblastic Leukemia in Adolescent and Young Adults

Background Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) accounts for 25% of acute lymphoblastic leukemia cases in the adolescent and young adult (AYA) age subgroup. It is associated with poor outcomes and is considered a standard indication for allogeneic stem cell transplant (Allo-SCT). Improved outcomes have been reported with addition of tyrosine kinase inhibitors (TKIs) to chemotherapy in children and the role of Allo-SCT is now being debated in the first remission. Complete response (CR) at three months is associated with improved survival even without Allo-SCT in first CR. In this study, we have analyzed disease-free survival (DFS), overall survival (OS), and factors affecting survival outcomes of Ph+ ALL in the AYA subgroup, in resource-limited settings treated with chemotherapy and TKIs. Materials and methods This is a retrospective, multicenter cohort study of Ph+ ALL AYA patients, aged 18-40 years, and registered between January 2015 and December 2020. Primary objectives are to calculate disease-free survival (DFS) and overall survival (OS). Secondary objectives are to identify prognostic factors affecting response rates and outcomes. List of cases was obtained from hospital information system (HIS) and data were collected from patient case notes and electronic medical records. Data analysis was done utilizing the SPSS statistical program (Armonk, NY: IBM Corp.). Results Forty-nine patients were identified with Ph+ ALL with a median age of 23 years (range: 18-40 years) and a male-to-female ratio of 2.5:1. None of the patients had central nervous system (CNS) disease. White cell count was >30,000 per mm(3) in 26% of patients, while 13% had additional cytogenetic abnormalities. Thirty-three percent patients received adult (hyper-cyclophosphamide, vincristine, Adriamycin, and dexamethasone {CVAD}) protocols while 67% received pediatric-inspired (Berlin-Frankfurt-Munster {BFM} 2000 or UK-ALL 2003/2011) protocols. TKI therapy was received by 66% of patients during treatment (early: 37%; late: 29%) and 34% did not receive TKIs due to financial constraints. CR after induction was achieved in 69% cases. Induction mortality was 16%. The median DFS for the entire cohort was 27 months (0.93-53.06) and the median OS was 29 months (8.89-49.10). The median OS in Allo-SCT group was not reached vs 8.0±8.8 months (p=0.05) with chemotherapy only. The OS was significantly better in patients with no additional cytogenetic abnormalities, pediatric-inspired chemotherapy protocols, early use of TKIs in induction phase, Allo-SCT, and post-Allo-SCT use of TKIs. Conclusion Addition of TKIs to pediatric-inspired chemotherapy protocols in Ph+ ALL AYA patients and Allo-SCT results in better overall survival. TKI availability remains a significant issue in low-income countries due to significant financial burden on the patients. Allo-SCT continues to be an attractive option, particularly in low-income countries providing an option for cure in Ph+ ALL.