Distinct outcomes, ABL1 mutation profile, and transcriptome features between p190 and p210 transcripts in adult Philadelphia-positive acute lymphoblastic leukemia in the TKI era

Background The differential signaling and outcome of patients with p190 or p210 transcripts of BCR-ABL1 have been systematically investigated in chronic myeloid leukemia rather than in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL). Methods We analyzed the outcomes and ABL1 mutation profiles in 305 consecutive adult patients with Ph + ALL treated with chemotherapy plus tyrosine kinase inhibitors. We also studied transcriptome features in two newly diagnosed patients with p190 and p210 using single-cell RNA sequencing (scRNA-seq). Results P190 and p210 were found in 199 (65%) and 106 (35%) patients, respectively. Compared to patients with p190, a higher white blood cell count ( p = 0.05), platelet count ( p = 0.047), BCR-ABL1 transcript level ( p < 0.001 ), and lower bone marrow blasts ( p = 0.003) were found in patients with p210. Patients with p210 had fewer types of ABL1 mutations (4 vs. 16) and a higher prevalence of T315I and E225K/V mutations (91.3% vs. 68.6%; p = 0.031). Patients with p210 had a similar complete remission rate (91.0% vs . 90.1%; p = 0.805) but a lower complete molecular remission rate at 1 month (9.9% vs. 22.0%; p = 0.031) compared with p190. Patients with p210 had lower 3-year overall survival (OS) and disease-free survival (DFS) rates than those with p190 (3-year DFS: 10.4% vs. 9.2%, p = 0.069, 3-year OS: 44.3% vs. 38.2%, p = 0.018, respectively). Multivariate analysis revealed that p210 was independently associated with worse OS [HR 1.692 (95% CI 1.009–2.838), p = 0.046]. Allogeneic hematopoietic stem-cell transplantation (allo-HSCT) was associated with a better prognosis in patients with p210 ( p < 0.0001). In addition, scRNA-seq data showed distinct molecular and cellular heterogeneity between bone marrow cells of the two transcripts. Conclusions Ph + ALL patients with p190 and p210 had different clinical characteristics, outcomes, ABL1 mutation profiles, and transcriptome features. Allo-HSCT could improve the outcomes of patients with p210.