Evaluation of 5-year imatinib treatment of 458 patients with CP-CML in routine clinical practice and prognostic impact of different BCR-ABL cutoff levels

Evaluation of Molecular Response to Imatinib Mesylate Treatment in Iranian Patients With Chronic Myeloid Leukemia

BACKGROUND

Imatinib mesylate has revolutionized the treatment of patients with chronic myeloid leukaemia (CML); however, some patients fail to respond and have a poor prognosis. Evaluation of molecular response to imatinib is a sensitive method can help physicians make better and quicker therapeutic decisions in the course of this disease. This study aims to evaluate the molecular response to generic imatinib in Iranian patients with CML.

PATIENTS AND METHODS

This prospective study consisted of 255 newly diagnosed patients with CML who received imatinib. Molecular response was analyzed at 3 and 6 months from the start of the treatment and then every 6 months, and long-term outcomes, including overall survival (OS) and progression-free survival (PFS), were evaluated.

RESULTS

At a median follow-up of 34.8 months (range, 3-84 months, (the OS and PFS at 7 years were 94.3% and 92.9%, respectively. Eighty-four-month PFS rates in patients with a BCR-ABLIS ≤ 10% at 3 months and BCR-ABLIS ≤ 1% at 6 months were significantly higher than patients who did not obtain these levels of BCR-ABL transcripts (P = .004 and P < .0001, respectively). The proportion of patients who achieved major molecular response (MMR) was 44.1%, 52.97%, and 60.75% at 12, 18, and 24 months, respectively. At 12, 18, and 84 months, the PFS rates in patients who achieved MMR were significantly higher than in patients who did not achieve MMR (P = .002, P < .0001, and P = .003, respectively).

CONCLUSIONS

The data of this prospective study are highly comparable with that from clinical trials and prospective international studies.

The predictive value of early molecular response in chronic myeloid leukaemia patients treated with imatinib in a single real-world medical centre in a developing country

INTRODUCTION

The prognosis of patients with chronic myeloid leukaemia (CML) has improved since the introduction of imatinib. However, patients who do not achieve complete cytogenetic response (CCyR) and major molecular response (MMR) have poorer prognosis. Recent clinical trials have demonstrated that early and deeper cytogenetic and molecular responses predict a better long-term outcome. This study aimed to analyse the relationship between early molecular response and clinical outcome in a real-life setting.

METHODS

This retrospective study included all patients with CML, in chronic or accelerated phase, who were treated with imatinib at University of Malaya Medical Centre, Malaysia.

RESULTS

A total of 70 patients were analysed. The median follow-up duration was 74 months, and the cumulative percentages of patients with CCyR and MMR were 80.0% and 65.7%, respectively. Overall survival (OS) and event-free survival (EFS) at ten years were 94.3% and 92.9%, respectively. Patients who achieved CCyR and MMR had significantly better OS and EFS than those who did not. At six months, patients who had a BCR-ABL level ≤ 10% had significantly better OS and EFS than those who had a BCR-ABL level > 10%. The target milestone of CCyR at 12 months and MMR at 18 months showed no survival advantage in our patients.

CONCLUSION

Our data showed that imatinib is still useful as first-line therapy. However, vigilant monitoring of patients who have a BCR-ABL level > 10% at six months of treatment should be implemented so that prompt action can be taken to provide the best outcome for these patients.

Current survival measures reliably reflect modern sequential treatment in CML: correlation with prognostic stratifications

Using the data of 723 chronic myeloid leukemia (CML) patients in the chronic phase, we analyzed the prognostic value of the Sokal, Euro, and EUTOS scores as well as the level of BCR-ABL1 and the achievement of complete cytogenetic response (CCgR) at 3 months of imatinib therapy in relation to the so-called current survival measures: the current cumulative incidence (CCI) reflecting the probability of being alive and in CCgR after starting imatinib therapy; the current leukemia-free survival (CLFS) reflecting the probability of being alive and in CCgR after achieving the first CCgR; and the overall survival. The greatest difference between the CCI curves at 5 years after initiating imatinib therapy was observed for the BCR-ABL1 transcripts at 3 months. The 5-year CCI was 94.3% in patients with BCR-ABL1 transcripts ≤ 10% and 57.1% in patients with BCR-ABL1 transcripts > 10% (P = 0.005). Therefore, the examination of BCR-ABL1 transcripts at 3 months may help in early identification of patients who are likely to perform poorly with imatinib. On the other hand, CLFS was not significantly affected by the considered stratifications. In conclusion, our results indicate that once the CCgR is achieved, the prognosis is good irrespective of the starting prognostic risks.