Treatment Free Remission (TFR) in Chronic Myeloid Leukaemia (CML): The Tawam Hospital Experience

Introduction:CML is a chronic myeloproliferative neoplasm that is characterized by presence of Philadelphia chromosome (a translocation between chromosomes 9 and 22 leading to BCR-ABL1 fusion gene and protein). This fusion can be detected by karyotyping, FISH and polymerase chain reaction (PCR). The therapy of CML has evolved from hydroxyurea, interferon, allogeneic stem cell transplant and lately tyrosine kinase inhibitors (TKI). The target of therapy is molecular response (MR) and has also evolved from the major molecular response (MMR), defined as ≥3-log reduction in BCR/ABL1fusion transcript using real-time quantitative PCR (RQ-PCR) to deep molecular response (DMR, ≥4-log reduction). The experience from a number of clinical trials, including STIM, TWISTER, A-STIM and KIDS, has generated interest in stopping TKIs in patients who have reached a sustained DMR. Hughes et al(Blood 2016) have published practical guidelines for selection of candidates for TFR and their subsequent management. Here we report our experience with TFR in patients with CML in DMR.