Dasatinib second and third-line treatment in chronic phase chronic myeloid leukemia

This study aimed to investigate the effectiveness and safety of dasatinib as a second- and third-line therapy in patients with chronic phase chronic myeloid leukemia (CP-CML). 

This study concluded that dasatinib was effective as a second-line treatment in these patients but showed limited effectiveness as a third-line treatment.  

Dasatinib (Sprycel) is a targeted therapy used to treat CP-CML. Dasatinib is a tyrosine kinase inhibitor (TKI) which works to prevent growth and spread of cancer. Second and third-line treatments are used when the first therapy fails.  

It was not known if dasatinib would be safe and effective as a second- or third-line treatment in CP-CML patients.  

This study involved 48 patients with CP-CML. Patients were split into two groups. Those who were receiving dasatinib as a second-line therapy (D2) and those who were receiving dasatinib as a third-line therapy (D3). 

The optimal molecular responses (OMR) at 3, 6 and 12 months were measured. The major molecular response (MMR) rate and complete cytogenic response (CCyR) were also measured. MMR is based on the number of leukemia cells in the blood. MMR means that the amount of BCR-ABL gene in the blood is at a low level. CCyR is based on mutated (abnormal) chromosomes. CCyR is when no cells with the Philadelphia chromosome can be found in the bone marrow. 

In the D2 group, 87% achieved the OMR at 3 months, 87% achieved OMR at 6 months and 72.2% achieved OMR at 12 months. 45.8% of patients in the D2 group achieved MMR. 72.7% of patients in the D2 group achieved CCyR. In the D3 group, 34.8% achieved the OMR at 3 months and at 6 months. 33.3% achieved OMR at 12 months. 20.8% of patients in the D3 group achieved MMR. 46.2% of patients in the D3 group achieved CCyR.   

A BCR-ABL1 (cancer gene) level of less than 10% at the start of dasatinib treatment was associated with a higher probability of achieving MMR. A BCR-ABL1 level of greater than 10% at the start of dasatinib treatment was associated with better performance as a second-line than third-line therapy.  

This study concluded that dasatinib was effective as a second-line treatment in CP-CML patients with a BCR-ABL1 level of less than 10% at the initiation of treatment. It was also concluded that dasatinib was less effective as a third-line treatment in patients with BCR-ABL1 greater than 10% at the start of treatment.  

This study has a small sample and short follow up period. Also, it included only Chinese participants. Further studies are needed.