[Treatment of two chronic myeloid leukemia patients with V299L mutation by using nilotinib]

This study was aimed to enhance clinical understanding the effect of nilotinib on CML patients with V299L mutation who were resistant to imatinib. Bone marrow specimens from 2 cases of CML with V299L mutation were collected before and after the treatment with nilotinib. ABL mutation was detected by nested reverse transcription polymerase chain reaction (PCR) followed by direct sequencing. The clinical characteristics of the two cases were analyzed. The results showed that both cases were resistant to imatinib presented V299L mutation. Out of them 1 case achieved complete haematological response (CHR) after treatment with nilotinib for 6 months and another case abstained obvious molecular response after using nilotinib for 7 month. V299L mutation of both cases was turned into negative after the treatment with nilotinib. It is concluded that the nilotinib can safely and effectively override tyrosine kinase inhibitor (TKI) resistance mediated by the V299L mutation. The safety and efficacy of nilotinib for treatment of CML patients with TKI resistance and V299L mutation are satisfactory.