Related Experiment Video
Updated: May 16, 2026
Comprehensive Protocol to Sample and Process Bone Marrow for Measuring Measurable Residual Disease and Leukemic Stem Cells in Acute Myeloid Leukemia
Published on: March 5, 2018
BCR-ABL1 Transcript ≤10% IS an Early Molecular Response Predictor of Treatment-Free Remission Eligibility in Chronic
Eman O Rasekh1, Menna M Sherif1, Nagwa Ibrahim1
1Clinical Pathology Department, National Cancer Institute, Cairo University, Cairo, Egypt.
Background:
Tyrosine kinase inhibitors (TKIs) have revolutionized chronic myeloid leukemia (CML) treatment. Early assessment of TKI response is crucial, and while deep molecular responses enable treatment discontinuation in selected patients, strict eligibility criteria are needed to prevent relapse. This study aimed to evaluate factors affecting early response to first-line imatinib in CML to help define criteria for safe treatment discontinuation and achieving treatment-free remission (TFR).
Patients And Methods:
This retrospective cohort study included all adult patients diagnosed with CML who received first-line imatinib therapy between February 2016 and February 2020.
Results:
A total of 144 adult patients with CML were included. The median age at diagnosis was 40 years (range: 21-76 years). Early molecular response (EMR), defined as BCR-ABL1 transcript level ≤10% international scale, was achieved in 72 of 116 evaluable patients (62%), and these patients demonstrated significantly superior event-free survival (p = .001), overall survival (p = .003), and failure-free survival (FFS, p < .001) compared with those without EMR. High-risk scores in SOKAL, ELTS, Hasford, and EUTOS systems were associated with EMR failure. Complete hematologic remission at 3 months (p = .001) and achieving BCR-ABL1 log reductions at 3, 6, and 12 months predicted improved FFS. The b3a2 BCR-ABL1 transcript and achieving BCR-ABL1 levels ≤10% at 3 months were both significantly linked to eligibility for treatment discontinuation (p = .04 and p < .0001, respectively).
Conclusion:
EMR should be considered a strong surrogate marker for identifying treatment failure. Imatinib-treated patients achieving EMR and carrying the b3a2 BCR-ABL1 transcript may be suitable for TFR if closely monitored under strict protocols.
Insights
Achieving early molecular response (EMR) with imatinib in chronic myeloid leukemia (CML) is vital for treatment success. Patients with EMR, especially those with the b3a2 BCR-ABL1 transcript, may be candidates for treatment-free remission (TFR) under close monitoring.
Area of Science:
- Hematology
- Oncology
- Molecular Biology
Background:
- Tyrosine kinase inhibitors (TKIs) have transformed chronic myeloid leukemia (CML) treatment.
- Early assessment of TKI response is critical for managing CML.
- Deep molecular responses can allow treatment discontinuation in select CML patients, necessitating strict criteria to prevent relapse.
Purpose of the Study:
- To evaluate factors influencing early response to first-line imatinib therapy in CML patients.
- To identify criteria for safe treatment discontinuation and achieving treatment-free remission (TFR).
Main Methods:
- Retrospective cohort study of adult CML patients receiving first-line imatinib.
- Data collected from February 2016 to February 2020.
- Analysis of factors affecting early molecular response (EMR) and survival outcomes.
Main Results:
- 62% of 116 evaluable CML patients achieved EMR (BCR-ABL1 ≤10%).
- EMR was associated with significantly superior event-free, overall, and failure-free survival (FFS).
- High-risk scores, complete hematologic remission at 3 months, and BCR-ABL1 log reductions predicted improved FFS; b3a2 transcript and BCR-ABL1 ≤10% at 3 months predicted TFR eligibility.
Conclusions:
- Early molecular response (EMR) is a strong indicator for predicting treatment failure in CML.
- Imatinib-treated CML patients with EMR and the b3a2 BCR-ABL1 transcript may be candidates for TFR with strict monitoring.
