Feasibility of treatment-free remission with generic imatinib: Results of generic imatinib-free trial-in-chronic myeloid leukaemia-chronic phase study

BACKGROUND & OBJECTIVES: Both innovator and generic imatinib are approved for the treatment of Chronic Myeloid Leukaemia-Chronic phase (CML-CP). Currently, there are no studies on the feasibility of treatment-free remission (TFR) with generic imatinib. This study attempted to determine the feasibility and efficacy of TFR in patients on generic Imatinib. METHODS: In this single-centre prospective Generic Imatinib-Free Trial-in-CML-CP study, twenty six patients on generic imatinib for ≥3 yr and in sustained deep molecular response (BCR ABL(IS) ≤0.01% for more than two years) were included. After treatment discontinuation, patients were monitored with complete blood count and BCR ABL(IS) by real-time quantitative PCR monthly for one year and three monthly thereafter. Generic imatinib was restarted at single documented loss of major molecular response (BCR ABL(IS)>0.1%). RESULTS: At a median follow up of 33 months (interquartile range 18.7-35), 42.3 per cent patients (n=11) continued to be in TFR. Estimated TFR at one year was 44 per cent. All patients restarted on generic imatinib regained major molecular response. On multivariate analysis, attainment of molecularly undetectable leukaemia (>MR(5)) prior to TFR was predictive of TFR [P=0.022, HR 0.284 (0.096-0.837)]. INTERPRETATION & CONCLUSIONS: The study adds to the growing literature that generic imatinib is effective and can be safely discontinued in CML-CP patients who are in deep molecular remission.