A 45-year-old woman has CML in chronic phase confirmed by BCR-ABL t(9;22). She is started on imatinib. After 12 months of therapy, BCR-ABL IS (International Scale) is 0.8% (>1 log reduction from baseline but not complete). By European LeukemiaNet (ELN) 2020 criteria, what is this response classified as?

• A Optimal response
• B Failure — switch TKI
• C Deep molecular response (DMR)
• D Warning — consider change or close monitoring ✓

Explanation

By ELN 2020 CML response milestones on TKI therapy, at 12 months: Optimal = BCR-ABL IS ≤0.1% (MMR, 3-log reduction); Warning = BCR-ABL IS 0.1–1%; Failure = BCR-ABL IS >1%. BCR-ABL IS of 0.8% at 12 months therefore constitutes a "Warning" response, which calls for increased monitoring, compliance assessment, and consideration of switching TKI generation. Deep molecular response (DMR, MR4.5) requires BCR-ABL IS ≤0.0032%.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.