Mixed phenotype acute leukemia: Biological profile, clinical characteristic and treatment outcomes: Report of the population‐based study

Abstract

Objectives The aim of this population‐based, retrospective study was to analyze biological and clinical features and treatment results in children diagnosed with MPAL in all Polish pediatric oncology centers between 2007 and 2018. Methods Among 2893 children and adolescents diagnosed and treated for acute leukemia, 39 (1.35%) patients fulfilled the WHO criteria of MPAL. The T/myeloid phenotype was most prevalent. Results Cytogenetics findings were seen in 2 (5.1%), while chromosomal abnormalities were found in 14 (35.9%) patients. Thirty‐two patients achieved CR‐1, including 23 (92.0%) treated with ALL‐directed chemotherapy and 9 (64.3%) treated with AML‐type induction regimens. Within these patients, 4 (12.5%) died due to treatment‐related complications and 11 (34.4%) relapsed. Nineteen (63.3%) patients underwent allo‐HSCT in CR‐1 and 14 (73.7%) of them have been in CR‐1. In total, 17 (43.6%) patients remain in CR‐1 for 1‐12 years, including 14 (58.3%) with T/myeloid MPAL. The 5‐year pOS and pEFS were 51.8% and 44.2%, respectively. The overall survival for ALL‐directed therapy was significantly better than the one for AML‐type chemotherapy (P = .001). It was also better for patients who underwent HSCT in CR‐1 (P = .001). Conclusions The prognosis of MPAL is unsatisfactory, but initial treatment with ALL‐directed chemotherapy consolidated with allo‐HSCT improves the outcomes in MPAL.

Case Report: Targeting 2 Antigens as a Promising Strategy in Mixed Phenotype Acute Leukemia: Combination of Blinatumomab With Gemtuzumab Ozogamicin in an Infant With a KMT2A-Rearranged Leukemia

“…Among 28 children treated for a MPAL with lymphoid-type treatment between 1996 and 2006 in the Czech Republic, 3 had a KMT2A/ AFF1 rearrangement, only one being alive after HSCT in CR2 (1). In a more recent series of 39 pediatric MPAL cases treated in Poland from 2007 to 2018, four cases presented with a KMT2A rearrangement but no details are provided regarding their specific treatment and outcome (7). An international cooperative study (18 centers participating in the iBFM-AMBI2012 study) looked at the therapeutic strategies and the outcome of 233 children with ambiguous lineage acute leukemia (ALAL) between 2002 and 2015 (176 single-population ALAL, 45 bilineal ALAL, 12 undifferentiated).…”

“…Lineage switch (B to M or vice versa) or persistence of only the lymphoid or myeloid clone is frequently observed in biphenotypic/bilineal cases, highlighting their lineage plasticity. Prognosis of MPAL remains bleak, with an event-free survival (EFS) of less than 50% in children (1,(5)(6)(7). A lymphoid-type therapeutic approach appears to be more effective (6, 7) but failures to achieve complete remission (CR) remain significant.…”

Pediatric Mixed-Phenotype Acute Leukemia: What’s New?

“…Patients treated with an ALL approach appear to be less likely to relapse than patients treated with an AML therapy approach. In addition, the remission durations of relapsed patients tend to be shorter, while age, lineage switch, and higher white counts are not predictive of worse outcomes per se [ 60 ].…”