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. 2012 Nov;37(11):640–648.

Table 2.

2009 European LeukemiaNet (ELN) and 2012 National Comprehensive Cancer Network (NCCN) Response Criteria In Patients With Chronic Myeloid Leukemia

ELN Guidelines NCCN guidelines
Hematological Response
Complete (CHR)

  • WBC count < 10 × 109/L

  • Platelet count < 450 × 109/L

  • Differential: no immature granulocytes; basophils < 5%

  • Nonpalpable spleen

  • Complete normalization of peripheral blood counts with leukocyte count < 10 × 109/L

  • Platelet count < 450 × 109/L

  • No immature cells, such as myelocytes, promyelocytes, or blasts, in peripheral blood

  • No signs or symptoms of disease (e.g., no palpable splenomegaly)
Cytogenetic Response
None > 95% Ph+ metaphases —
Minimal 66% to 95% Ph+ metaphases —
Minor 36% to 65% Ph+ metaphases > 35% Ph+ metaphasesa
Major — 0% to 35% Ph+ metaphasesa (complete + partial response)
Partial (PCyR) 1% to 35% Ph+ metaphases 1% to 35% Ph+ metaphasesa
Complete (CCyR) No Ph+ metaphasesb No Ph+ metaphasesa
Molecular Response
Major (MMR) Ratio of BCR–ABL1 to ABL (or other housekeeping genes) ≤ 0.1% on the International Scale ≥ 3-log reduction in International Scale of BCR–ABL1 mRNA
Complete (CMR) Undetectable BCR–ABL1 mRNA transcripts by real-time quantitative and/or nested PCR in two consecutive blood samples of adequate quality (sensitivity > 104) BCR–ABL1 mRNA undetectable by RT–PCR

CBC = complete blood count; mRNA = messenger RNA; Ph+ = Philadelphia chromosome–positive; PCR = polymerase chain reaction; RT–PCR = reverse transcription polymerase chain reaction; WBC = white blood cell.

a

A minimum of 20 metaphases should be examined.

b

If marrow cell metaphases cannot be obtained or evaluated by chromosome banding analysis, the definition of CCyR may be based on interphase FISH of blood cells, provided that it is performed with BCR–ABL1 extrasignal, dual color, dual fusion, or in situ hybridization probes, and that at least 200 nuclei are scored. CCyR = < 1% BCR–ABL1-positive nuclei. In many studies, PCyRs and CCyRs are counted together and reported as major CyRs.

Adapted with permission from NCCN Guidelines for Chronic Myelogenous Leukemia.13

Additional data from O’Brien SG, et al. N Engl J Med 2003;348)11):994–1004;10 Baccarani M, et al. Best Pract Res Clin Haematol 2009;22(3):331–341;12 Hughes TP, et al. N Engl J Med 2003;349(15):1423–1432.22