Treatment options for chronic myeloid leukemia patients with failed imatinib treatment

This study aimed to investigate the safety and effectiveness of dasatinib (Sprycel) and nilotinib (Tasigna) in chronic phase chronic myeloid leukemia patients with failed imatinib (Gleevec) treatment.

This study concluded that dasatinib and nilotinib were safe and effective in this group of patients.

Chronic phase chronic myeloid leukemia (CP-CML) is usually treated with imatinib, a tyrosine kinase inhibitor (TKI). Imatinib targets an enzyme produced by the abnormal BCR-ABL1 gene, which is a cancer-causing gene found in CP-CML patients. However, imatinib does not work for some patients and a second-generation TKI (2G-TKI) is needed. Dasatinib and nilotinib are 2G-TKIs that lead to good responses in patients who fail imatinib treatment. These 2G-TKIs have led to complete cytogenic response (CCyR) rates of about 50% and major molecular response (MMR) rates of about 40%. CCyR is when no BCR-ABL1 can be found in the bone marrow. MMR is when there is only a small amount of BCR-ABL1 in the bone marrow.

It was not known if dasatinib or nilotinib would be more effective and if they would provide deep molecular response (DMR; no BCR-ABL found in bone marrow) for patients with CP-CML.

This study involved information on 163 CP-CML patients who received dasatinib or nilotinib after imatinib failure. The two groups were compared. Patients were followed for an average of 48 months.

75% of patients who were not in CCyR when they started 2G-TKI achieved CCyR. 60% of patients who were not in MMR when they started 2G-TKI achieved MMR.

DMR was achieved by 37.4% of patients. The rate of stable DMR at 5 years was 24%. Stable DMR is needed to end treatment.

After 48 months 60% of patients continued 2G-TKI treatment. The most common side effect with dasatinib was fluid around the lungs (10.5%). The most common side effect with nilotinib was peripheral arterial obstructive disease (blockage of an artery in the leg, 5.8%).

Dasatinib and nilotinib showed similar cytogenic responses, molecular responses, progression free survival (time from treatment until disease progression) and overall survival (time from treatment until death from any cause).

This study concluded that dasatinib and nilotinib had equal effectiveness and safety after imatinib failure. This study also concluded that 2G-TKIs achieved high rates of CCyR, MMR and good chance of stable DMR.

Discuss with your physician what options are available after imatinib failure.