Page 13 - 2020_07-Haematologica-web

Editorials
This article is valuable to clinicians as it confirms the adverse presenting features, poor early response and EFS/OS rates of a large cohort of ABL-class fusion positive B-ALL patients, similar to prior anecdotal reports7 or smaller retrospective series.8,10 Moreover, the authors highlight the striking clinical resemblance between ABL- class fusion positive B-ALL and Ph+ ALL. Both disease entities comprise approximately 3% of pediatric ALL, tend to be older patients with hyperleukocytosis, elevat-
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BC
ed MRD at the end of induction and consolidation, and the reported 5-year EFS of less than 50% for the ABL- class cohort mirrors that of Ph+ ALL in the pre-TKI era treated with the same chemotherapy backbone.11,12 This has important therapeutic implications, suggesting that the addition of TKI to chemotherapy, which has trans- formed survival of Ph+ ALL, may similarly translate into improved outcomes for ABL-class patients.13,14 In this series, six of the eight ABL-class patients who started TKI
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Figure 1. (A) Frequency of Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL), Ph-like ALL and ABL-class fusions in B-lineage ALL (B-ALL) according to National Cancer Institute (NCI) risk status and age group, based on the following studies: Roberts et al.,21 Reshmi et al.,5 Roberts et al.,4 and Roberts et al.6 NCI SR: National Cancer Institute Standard Risk; NCI HR: National Cancer Institute High Risk. (B) Frequency of ABL-class fusions in Ph-like ALL. (C) Outcomes of ABL-class fusion positive B-ALL patients treated on the AIEOP-BFM ALL 2000 and 2009 trials. pEFS: projected event-free survival; pOS: projected overall survival. (D) Proposed treatment paradigm for ABL-class fusion positive B-ALL. Early introduction of tyrosine kinase inhibitor (TKI) to induction chemotherapy to achieve remis- sion. Good-responders may continue with TKI and post-induction chemotherapy. Poor-responders will undergo allogeneic hematopoietic stem cell transplantation in first remission (CR1). Incorporation of immunotherapy with or without TKI is being considered in future trials to improve outcomes. yr: year.
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