Table 2.

ELN response criteria and recommended monitoring frequency in first‐line treatment of CML^a (Baccarani et al, 2013)

Time since start of TKI treatment	ELN response category
	Optimal		Warning		Failure
	Response criteria	Monitoring	Response criteria	Monitoring	Response criteria	Monitoring
Baseline	NA	CBA, Qualitative PCR	High risk or CCA/Ph+, major route	CBA, Qualitative PCR	NA	CBA, Qualitative PCR
3 months	BCR‐ABL1 ≤10% and/or Ph+ ≤35%	RT‐qPCR every 3 months until MMR, then every 3–6 months and/or CBA at 3, 6 and 12 months until CCyR, then FISH	BCR‐ABL1 >10% and/or Ph+ 36–95%	Molecular/cytogenetic tests to be performed more frequently (up to monthly)b	No CHR and/or Ph+ >95%	RT‐qPCR, mutational analysis, and CBA should be performed. Immunophenotyping in blastic phase.
6 months	BCR‐ABL1 <1% and/or Ph+ 0		BCR‐ABL1 1–10% and/or Ph+ 1–35%		BCR‐ABL1 >10% and/or Ph+ >35%
12 months	BCR‐ABL1 ≤0·1%		BCR‐ABL1 >0·1–1%		BCR‐ABL1 >1% and/or Ph+ >0
≥12 months	BCR‐ABL1 ≤0·1%		CCA/Ph− (−7, or 7q−)		Loss of CHR, Loss of CCyR, confirmed loss of MMRc

CBA, chromosome banding analysis of marrow cell metaphases; CCA/Ph⁺, clonal chromosome abnormalities in Philadelphia chromosome‐positive cells; CCA/Ph⁻, clonal chromosome abnormalities in Philadelphia chromosome‐negative cells; CCyR, complete cytogenetic response; CHR, complete haematological response; CML, chronic myeloid leukaemia; ELN, European LeukaemiaNet; FISH, fluorescence in situ hybridisation; MMR, major molecular response; NA, not applicable; PCR, polymerase chain reaction; Ph, Philadelphia chromosome; RT‐qPCR, reverse transcriptase quantitative polymerase chain reaction.

^aThe definitions are the same for patients in chronic phase, accelerated phase and blast phase and also apply to second‐line treatment, when first‐line treatment was changed for intolerance.

^bCBA recommended in case of myelodysplasia or CCA/Ph‐ with chromosome 7 involvement.

^cIn two consecutive tests of which one is with a BCR‐ABL1 transcript level of ≥1%.