10-years on: Imatinib as a first-line therapy for CML

This study examined treatment combinations involving imatinib (Gleevec) for chronic myeloid leukemia (CML). Researchers concluded that treatment with standard-dose imatinib achieved a survival comparable to that of the general population. Patient disease factors affected outcomes more than initial treatment selection.

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, such as imatinib, are a type of targeted therapy that block enzymes called tyrosine kinases. Increasing the dosage of imatinib or combining it with the immunotherapy interferon (Intron) or the chemotherapy cytarabine (Cytosar-U) may increase its effectiveness.

1,536 newly diagnosed CML patients were randomly assigned to 1 of 5 treatment groups. 400 patients were treated with imatinib at 400 mg per day. 420 patients received imatinib at 800 mg. 430 patients received imatinib plus interferon. 158 patients received imatinib plus cytarabine. 128 patients were treated with imatinib after failure of interferon. Average follow-up was 9.5 years.

The average 10-year overall survival rate (proportion who have not died from any cause since treatment) was 82%. 80% of all patients were progression-free at 10 years. No significant differences in survival were observed between the 5 treatment groups.

More deaths were unrelated to CML (169 in total) compared to CML-related deaths (83 in total). The 10-year probability of mortality due to CML was 6%. The non-CML causes of death correspond to those observed in the general population.

Factors such as disease risk score, additional medical conditions, chromosomal abnormalities (making CML more difficult to treat), smoking, and the type of treatment center affected survival. Gender, the type of chromosomal abnormality, and the type of first-line treatment did not.

This study concluded that the standard dose of imatinib achieved a similar survival to that observed in the general population. The standard dose of imatinib is as effective as the doubled dose or combinations with interferon or cytarabine.

The authors received funding from the manufacturers of the drugs used in this study.