13
Table 5. IMWG Response Criteria
Response IMWG criteria
1
sCR CR as defined below plus normal free light chain (FLC) ratio and
absence of clonal cells in bone marrow
2
by immunohistochemistry or
immunofluorescence
3
CR Negative immunofixation on the serum and urine and disappearance
of any so tissue plasmacytomas and <5% plasma cells in bone
marrow
2
VGPR Serum and urine M-protein detectable by immunofixation but not
on electrophoresis or >90% reduction in serum M-protein plus urine
M-protein level <100 mg/24 h
PR ≥50% reduction of serum M-protein and reduction in 24 hours
urinary M-protein by ≥90% or to <200 mg/24 h
If the serum and urine M-protein are unmeasurable,
4
a ≥50% decrease
in the difference between involved and uninvolved FLC levels is
required in place of the M-protein criteria
If serum and urine M-protein are not measurable, and serum free
light assay is also not measureable, ≥50% reduction in plasma cells is
required in place of M-protein, provided baseline bone marrow plasma
cell percentage was ≥30%
In addition to the above listed criteria, if present at baseline, a ≥50%
reduction in the size of so tissue plasmacytomas is also required
MR NA
No change/
Stable disease
Not meeting criteria for CR, VGPR, PR, or progressive disease
Plateau NA
Progressive
disease
4
Increase of ≥25% from lowest response value in any one or more of the
following :
• Serum M-component and/or (the absolute increase must be
≥0.5 g/dL)
5
• Urine M-component and/or (the absolute increase must be
≥200 mg/24 h)
• Only in patients without measurable serum and urine M-protein
levels; the difference between involved and uninvolved FLC levels.
The absolute increase must be >10 mg/dL
• Bone marrow plasma cell percentage; the absolute percentage must
be ≥10%
6
• Definite development of new bone lesions or soft tissue
plasmacytomas or definite increase in the size of existing bone
lesions or soft tissue plasmacytomas
• Development of hypercalcaemia (corrected serum calcium >11.5
mg/dL or 2.65 mmol/L) that can be attributed solely to the plasma
cell proliferative disorder
