Comparison of Response to Treatment with Imatinib Versus Nilotinib in the Initial Three Months in Chronic Myeloid Leukaemia

BACKGROUND Chronic myeloid leukemia (CML) accounts for 15 - 20 % of leukemia in adults worldwide. At present, the three tyrosine kinase inhibitors (TKI) imatinib, dasatinib, or nilotinib are accepted as the standard first-line treatment in chronic phase (CP). Nilotinib is a second generation TKI having faster and deeper response compared to imatinib. We wanted to see if the response achieved with nilotinib in the first three months could be translated into long term benefits when imatinib was given after 3 months. METHODS Newly diagnosed CML-CP patients were randomized into two arms. The patients on the first arm were given imatinib and in the second arm nilotinib was given for first 3 months. After three months nilotinib was switched over to imatinib. The molecular response was assessed in both arms at 3 months and 6 months. RESULTS Twenty-six patients in each arm were analysed. The optimal molecular response (QPCR <10 %) after 3 months was significantly higher in patients receiving nilotinib than imatinib (96.1 % vs 65.38 %; P < 0.0048). The optimal response after 6 months (QPCR < 1 %) was found to be more in the initial nilotinib arm than the initial imatinib arm (76.9 % vs 65.3 %; P - value = 0.35). CONCLUSIONS Patients on nilotinib arm did well even after switching to imatinib. It gives us an important platform for an economically backward country like India where the therapy with more potent drug like nilotinib is given in the initial three months or even six months. KEYWORDS Chronic Myeloid Leukaemia, Imatinib, Nilotinib, Optimal Response, Major Molecular Response