Hematopoietic stem cell transplant versus chemotherapy plus tyrosine kinase inhibitor in the treatment of pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia (ALL)

Abstract

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) remained until recently the molecular genetic abnormality associated with the worst outcome. Hematopoietic stem cell transplant (HSCT) was considered the treatment of choice, however, recent data have indicated that chemotherapy plus tyrosine kinase inhibitor (TKI) maybe an alternative effective therapy. We conducted a retrospective analysis of children (<18 years) with Ph+ ALL who were treated at King Hussein Cancer Center (KHCC) from January 2003 till December 2011. Over a 9 year period, 411 children were diagnosed and treated for ALL at KHCC. Twenty three (6.6%) had Ph+ ALL; 16 males and 7 females. Median age at diagnosis was 9.5 years (range 1.67-17). The median white blood cell count was 58.6×10(3)/μL (range 1.6-459). Twelve patients underwent HSCT from a full matched related donor; and 10 were treated with intensive chemotherapy plus TKI (imatinib). Those who underwent HSCT were significantly older (P=0.004) and had a higher leukocyte count at diagnosis (P=0.53). After a median follow up of 42.2 months (range 12.7-107), the estimated 5 year event free survival (EFS) and overall survival (OS) were 75% and 91.6%, respectively, for those who underwent HSCT as primary therapy and 49.3% and 83.3%, respectively, for those treated with chemotherapy plus imatinib. There was no significant difference in EFS (P=0.98) or OS (P=1) between the two treatment modalities. Our results indicate that chemotherapy plus TKI may be a reasonable treatment option for some children with Ph+ ALL.