Targeted therapy with tyrosine kinase inhibitors (TKIs) has changed the landscape of CML management. They became a global standard of initial treatment where most patients with CML treated with TKIs achieve a complete cytogenetic response. Even after achieving this goal its disease burden continues to decrease with further treatment. Therefore, more sensitive polymerase chain reaction (PCR)–based molecular methods are required to detect and quantify levels of minimal residual disease (MRD).
Low levels of MRD, as measured by real-time quantitative PCR (RQ-PCR) of BCR-ABL RNA, have been shown to be an excellent surrogate marker for long-term outcome. Therefore, BCR-ABL RQ-PCR test has now becoming an essential tool in the management of CML. This molecular testing of peripheral blood samples is more convenient than bone marrow sampling, which is usually required for cytogenetic monitoring and furthermore molecular testing correlates well with clinical response. Doing frequent blood-based molecular testing may reduce the need for invasive bone marrow testing. The European LeukemiaNet and the National Comprehensive Cancer Network recommend RQ-PCR–based molecular monitoring every 3 months until a deep response (i.e., major molecular response [MMR] or CCyR) occurs and every 3–6 months thereafter.
However this test requires standardized and harmonized method of reporting so that the optimal clinical outcome could be defined homogenously across the globe. Haematology lab, HUSM has taken this challenge to provide molecular monitoring test for CML patients who is on active TKI therapy. This seminar is aimed to strengthen the laboratory methods so that its clinical interpretation will able to guide physicians in the management of CML patients.