Real-world clinical outcomes for patients with chronic myeloid leukemia who needed to switch from second generation TKI therapy.

This study described real-world outcomes for patients with chronic myeloid leukemia (CML) that started a second-generation tyrosine kinase inhibitor (TKI) therapy and needed to switch to an alternative TKI. The authors concluded that intolerance was the major reason to switch to an alternative TKI and that outcomes were very good for these patients. 

CML is a type of bone marrow and blood cancer. This form of leukemia is due to a cancer-causing gene called the BCR-ABL gene. Targeted therapies that block this gene called BCR-ABL TKIs have improved the outcomes of patients with CML. Imatinib (Gleevec) is the first TKI developed and is considered first-generation. Second-generation TKIs include dasatinib (Sprycel) and nilotinib (Tasigna) and are used in patients with intolerance or resistance to imatinib.  

Despite the effectiveness of second-generation TKIs, first-line therapy is sometimes stopped. However, data on the frequency of patients stopping second-generation TKIs in a real-world setting remains limited and requires investigation.

This study included 232 patients with chronic phase CML, that received first-line therapy with dasatinib (187 patients) or nilotinib (45 patients). 76 patients (32.8%) were switched to an alternative TKI, after an average of 10 months after starting first-line therapy. Reasons for switching and outcomes were evaluated.

60 patients were switched to an alternative TKI due to intolerance. 88% of these patients maintained major molecular response (MMR; the quantity of the BCR-ABL gene is less than 0.001) and 90.5% were alive without cancer worsening after 5 years. Most of these patients remained on second-line TKI.

16 patients were switched to an alternative TKI because of resistance. 8 patients achieved MMR after the switch. 80.4% were alive without cancer worsening after 5 years.

Overall, 95.2% of the patients that switched due to intolerance, and 80% of those that switched because of resistance were alive after 5 years.

The study indicated that intolerance was the major reason for a treatment switch from first-line dasatinib or nilotinib therapy in patients with CML and the outcomes of these patients were very good.

This study was based on medical records. Some data might have been missing. One factor that is important is adherence to treatment which could not be verified.