Table 2.

Measures of response in chronic myeloid leukemia and prognostic significance [2,13–15]

Response type	Definition	Prognostic significance
Hematologic (HR)	Complete normalization of peripheral blood counts with leukocyte count <10 × 109/L Platelet count <450 × 109/L No immature cells, eg myelocytes, promyelocytes, or blasts in peripheral blood No signs and symptoms of disease with disappearance of palpable splenomegaly	Failure to achieve an HR at 3 months predicts poor outcomes
Cytogenetic (CyR)	Complete: no Ph-positive metaphases Partial: 1–35% Ph-positive metaphases Major: 0–35% Ph-positive metaphases Minor: 36–65% Ph-positive metaphases Minimal: 66–94% Ph-positive metaphases None: ≥95% Ph-positive metaphases	Complete CyR (CCyR) is the best early predictor for good long-term outcomes Achievement of CyR at 3 and 6 months and of CCyR at 12 and 18 months are regarded as key targets
Molecular (MR)	Complete: BCR-ABL mRNA undetectable by reverse transcriptase polymerase chain reaction Major: ≥3-log reduction (or ≤0.1%) on the International Scale of BCR-ABL mRNA	Although of prognostic value, the timing and grade of response remains controversial Loss of MR is also of prognostic significance

Ph, Philadelphia chromosome.