Table 5 International Myeloma Working Group uniform response criteria: CR and other response categories

From: International uniform response criteria for multiple myeloma

Response subcategory Response criteria a
CR  Negative immunofixation on the serum and urine and
   Disappearance of any soft tissue plasmacytomas and
 5% plasma cells in bone marrowb
sCR CR as defined above plus
   Normal FLC ratio and
   Absence of clonal cells in bone marrowb by immunohistochemistry or immunofluorescencec
VGPR  Serum and urine M-component detectable by immunofixation but not on electrophoresis or
   90 or greater reduction in serum M-component plus urine M-component <100 mg per 24 h
PR 50% reduction of serum M-protein and reduction in 24-h urinary M-protein by 90% or to <200 mg per 24 h
   If the serum and urine M-protein are unmeasurable,d a 50% decrease in the difference between involved and uninvolved FLC levels is required in place of the M-protein criteria2, 3
   If serum and urine M-protein are unmeasurable, and serum free light assay is also unmeasurable, 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 soft tissue plasmacytomas is also required
SD (not recommended for use as an indicator of response; stability of disease is best described by providing the time to progression estimates)  Not meeting criteria for CR, VGPR, PR or progressive disease
  1. Abbreviations: CR, complete response; FLC, free light chain; PR, partial response; SD, stable disease; sCR, stringent complete response; VGPR, very good partial response.
  2. a All response categories require two consecutive assessments made at anytime before the institution of any new therapy; complete and PR and SD categories also require no known evidence of progressive or new bone lesions if radiographic studies were performed. Radiographic studies are not required to satisfy these response requirements.
  3. b Confirmation with repeat bone marrow biopsy not needed.
  4. c Presence/absence of clonal cells is based upon the k/λ ratio. An abnormal k/λ ratio by immunohistochemistry and/or immunofluorescence requires a minimum of 100 plasma cells for analysis. An abnormal ratio reflecting presence of an abnormal clone is k/λ of >4:1 or <1;2. Alternatively, the absence of clonal plasma cells can be defined based on the investigation of phenotypically aberrant PC. The sensitivity level is 10−3 (less than one phenotypically aberrant PC within a total of 1000 Pc). Examples of aberrant phenotypes include (1) CD38 +dim and CD56+ strong and CD19 and CD45; (2) CD38+dim and CD138+ and CD56++ and CD28+; (3) CD138+, CD19 CD56++, CD117+.
  5. d Refer to Table 4 for definitions of measurable disease
  6. References
  7. 1. Wei A, Juneja A. Bone marrow immunohistology of plasma cell neoplasms. J Clin Pathol 2003; 56: 406–411.
  8. 2. San Miguel JF, Almeida J, Mateo G et al. Immunophenotypic evaluation of the plasma cell compartment in multiple myeloma: a tool for comparing the efficacy of different treatment strategies and predicting outcome. Blood 2002; 99: 1853–1856.