 Imatinib is the first tyrosine kinase inhibitor TKI, which has changed the treatment paradigm of CML since its approval from U.S. Food and Drug Administration in 2001 for the treatment of CML. It signifies a new era of oncological treatment using targeted therapy. Subsequent generation TKIs have been marketed as a more potent therapy for CML. Tyrosine kinase inhibitor is conventionally thought not able to cure CML and it has to be taken for life. It is able to induce a very deep molecular response MR in about 10 of CML patients as evidenced by persistent undetectable or 0.0032 International Scale IS BCR-ABL1 transcript in quantitative polymerase chain reaction PCR test on current molecular assays, which is labelled as MR4.5 or more. However these patients have to continue taking their TKIs as per recommendations from the European Leukaemia Net and this is the current practice in our institution and in Malaysia. Long term treatment is cumbersome, there is a concern of chronic side effects with long term tyrosine kinase inhibition and it is a financial burden on most countries health budget as these drugs are very expensive. 