The outcomes of stem cell transplant for patients with blast crisis chronic myeloid leukemia pretreated with tyrosine kinase inhibitors

This study aimed to investigate the outcomes of stem cell transplant in patients with blast crisis chronic myeloid leukemia who were pre-treated with tyrosine kinase inhibitors.  

This study concluded that the survival of these patients was strongly dependent on pretransplant remission status. 

The outcome for patients with blast crisis (BC) chronic myeloid leukemia (CML) is commonly very poor. BC or blast phase CML is the phase where there are 20% or more blasts in the blood. Blasts are precursor cells (young) for red blood cells, white blood cells, and platelets. BC-CML makes it difficult to control the level of cells present.  

Allogenic hematopoietic stem cell transplant (allo-HSCT) is the only curative treatment option for patients with BC-CML. Allo-HSCT is a procedure in which a person receives blood-forming stem cells from a donor. 

Patients may receive tyrosine kinase inhibitors (TKI) treatment before allo-HSCT. TKIs work to block the protein (tyrosine kinase) produced by the BCR-ABL cancer gene. It was not known what the outcomes of allo-HSCT in BC-CML patients would be.  

This study involved 170 adult patients with BC-CML who received allo-HSCT. All patients previously received TKI treatment. Before allo-HSCT, 95 patients were in remission and 75 patients had active BC-CML.  

Active BC-CML at the time of transplant was the strongest factor associated with decreased overall survival (OS) and shorter leukemia-free survival (LFS).  

Some risk factors for a lower survival for patients with BC-CML in remission at the time of transplant were advanced age, lower performance status and longer time from diagnosis to transplant. Other risk factors included myeloablative conditioning (bone marrow destroyed) and unrelated donor (UD) transplant.   

In patients with active BC-CML, UD transplant was significantly associated with a prolonged LFS and improved OS.   

This study concluded that the survival of patients treated with an allo-HSCT for BC-CML was strongly dependent on pretransplant remission status. 

This study was based on medical records. Some information was missing, which might have influenced the results. Further studies are needed.