Outcomes of Pediatric Mixed Phenotype Acute Leukemia Treated with Lymphoid Directed Therapy: Analysis of an Institutional Series from India

There is limited data regarding pediatric mixed phenotype acute leukemia (MPAL) and there is no global consensus on its management yet. In this retrospective study, we analyzed the outcomes of children diagnosed with MPAL at our institute. This study included children ≤ 14 years with MPAL who presented to a tertiary cancer center in India from January 1st 2009 to December 31st 2015. Over a seven-year period, 1390 patients with leukemia presented to our institute of which 22 patients (1.5%) had MPAL. Sixteen patients (72.7%) had B/myeloid leukemia, while 4 (18.1%) and 2 (9%) patients had T/myeloid and B/T leukemia respectively. Twenty-one patients were treated with a modified BFM ALL 95 protocol. 76.1% (n = 16) of patients had a good prednisolone response (GPR) on day 8 and end-of-induction (EOI) marrow was in remission in 90.5% (n = 19). A poor prednisolone response (PPR) on day 8 correlated with an inferior relapse-free survival (25% vs 79.5%, P=.025). The 4-year event-free survival (EFS) and overall survival (OS) for the entire group was 60.8% and 64.9% respectively while the EFS for patients who had a GPR and remission at the EOI (n = 15) was 80% as compared to 16.7% in patients with PPR or induction failure. Lymphoid directed chemotherapy is seen to have good survival outcomes in pediatric MPAL. However, a PPR on day 8 or a positive EOI marrow may be an indication for more aggressive treatment.