Examining predictors of treatment response to dasatinib

This study examined treatment outcomes with dasatinib (Sprycel) for chronic myeloid leukemia (CML). Researchers reported a fast and strong treatment response to first-line dasatinib, particularly in older patients. The levels of a genetic mutation known as BCR-ABL1 at 3 months was found to be a predictor of treatment response.

Targeted therapy is the standard first-line treatment for CML. This refers to a type of treatment that uses drugs or small molecules that block the growth and spread of cancer. Tyrosine kinase inhibitors are a type of targeted therapy that block enzymes called tyrosine kinases. Dasatinib is a recently developed tyrosine kinase inhibitor. Early studies are showing good effectiveness. However, more studies are needed.

Treatment response is often measured based on patients showing decreased abnormal chromosomes (cytogenetic response) or genetic abnormalities (molecular response) in the blood or bone marrow. Major molecular response is often considered the main goal of CML treatment.

This study examined the effectiveness of dasatinib as a first-line treatment for CML. 79 patients with newly diagnosed CML were included in this study. All patients were treated with first-line dasatinib (at 100 mg). Factors that affected treatment outcomes were analyzed.

88.6% of patients achieved complete cytogenetic response at 12 months. 77.2% of patients achieved major molecular response at 12 months. Deep molecular response (the strongest form of treatment response) was observed in 35.4%.

Gender and disease risk score were not found to affect molecular response rates. Having a level of a genetic mutation known as BCR-ABL1 transcript below 54% at diagnosis also did not affect this result. However, being older than 65 years increased the chances of achieving deep molecular response almost 3-fold.

74 patients (93.7%) achieved BCR-ABL1 transcript levels of 10% or lower at 3 months. The reduction rate of BCR-ABL1 within the first 1 to 3 months of therapy was found to be a significant predictor of deep molecular response.

7.6 to 10.1% of patients experienced serious blood-related side effects such as low red or white blood cell counts. Other side effects included fluid in the lungs (29.1%), rash (17.7%), difficulty breathing (17.7%), diarrhea (11.4%), and fatigue (10.1%).

This study concluded that first-line treatment with dasatinib is safe and effective. 

This was an early-phase study that needs to be validated by further clinical trials.