Non-inferior long-term outcomes of adults with Philadelphia chromosome-like acute lymphoblastic leukemia

Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) is associated with inferior outcomes in the chemotherapy setting. We hypothesized that allogeneic hematopoietic cell transplantation (allo-HCT)-based post-remission therapy would improve outcomes of this entity. We examined the frequency and long-term outcomes of adults with Ph-like ALL, particularly focusing on allo-HCT outcomes for Ph-like ALL versus non-Ph-like ALL. Ph-like ALL was determined by anchored multiplex PCR-based targeted next-generation sequencing. Of the 344 patients, 57 (16.6%) had Ph-like ALL, 197 (57.3%) had Ph-positive ALL, and 90 (26.1%) had B-other ALL. To further evaluate the prognosis of Ph-like ALL, outcome analyses were restricted to 147 patients, excluding Ph-positive ALL. The actual allo-HCT rates in complete remission were 87.7% for Ph-like ALL, 71.4% for B-other standard-risk ALL, and 70.4% for B-other poor-risk ALL. Patients with Ph-like ALL had a higher 5-year overall survival (60.6% vs 27.1%; P = 0.008) than B-other poor-risk ALL subgroup, while no difference was observed compared with B-other standard-risk ALL subgroup. Similar results were noted in a separate analysis for patients receiving allo-HCT in complete remission. In multivariate analyses, B-other poor-risk ALL was associated with poorer outcomes. Our data showed that allo-HCT-based post-remission therapy may have contributed to non-inferior outcomes of adult Ph-like ALL.