Hybrid chemotherapy regimen (FLAG-IDA-vincristine-prednisone) for acute leukemia with mixed-phenotype blasts

Acute leukemia with mixed-phenotype blasts is associated with poor outcomes. There are no standard treatment regimens. Due to disease heterogeneity, controversy exists over whether an AML-based, ALL-based, or a combined (hybrid) AML/ALL-based regimen is most appropriate.

We conducted a single-center, retrospective case series review of patients with acute leukemia with mixed phenotype blasts as described by the European Group for Immunological Characterization of Leukemia (EGIL) or the 2008 WHO classification. Patients were treated from November 2014 and December 2019 with the combination chemotherapy regimen FLAG-idarubicin-vincristine-prednisone with or without rituximab. Outcomes included induction response, time to transplant, time to relapse, overall survival, time to neutrophil or platelet recovery, infection, and duration of hospitalization.

The median age was 68 years (range 21-77). Six patients (87.5 %) had unfavorable/complex cytogenetics. All patients achieved a complete remission (CR) or complete remission with incomplete hematologic recovery (CRi). Estimated 1-year overall survival was 85.7 %. There were no deaths during induction, with a 22 day median duration of hospitalization for induction.

The combination of FLAG, idarubicin, vincristine, and prednisone (FLAG-VIPR) demonstrated favorable induction responses in a disease state with historically poor outcomes and should be studied in a prospective clinical trial.