By Jennifer Ahlstrom | Posted - Sep 14th, 2020

 

 

 

 

Response Definitions After Myeloma Treatment

When your doctor tells you that your multiple myeloma is "in remission", what exactly does that mean? Myeloma experts divide patients into different response categories following treatment according to CIBMTR. These response levels are used in myeloma clinical trials to indicate a more granular way of measuring response to therapy. 

Minimal residual disease (MRD) testing is now even more sensitive than the descriptions below. Achieving MRD negativity is preferred following treatment, but some patients have continuous low levels of disease for long periods of time. We anticipate that more study on MRD testing will be performed and get us closer to a way of predicting long-term outcomes. Today, MRD testing is being used in clinical trials but is not necessarily used to determine whether treatment will be stopped. 

So the next time you are tested following myeloma therapy, ask your doctor what type of response you achieved and then reference the below to better understand what it means. 

Stringent Complete Response

  • Normal free light chain ratio
  • No myeloma in the bone marrow
  • A kappa lambda ratio on less than 4:1 (for kappa patients) or over 1:2 (for lambda patients)  counting 100 plasma cells

Complete Response (CR)

  • Negative immunofixation on blood and urine samples
  • Disappearance of any soft tissue plasmacytomas
  • < 5% plasma cells in the bone marrow 

Very Good Partial Response (VGPR)

  • Heavy Chain Myeloma (e.g., IgG kappa, IgG lambda, IgG only, etc.)
    • Serum and urine M-protein detectable by immunofixation but not on electrophoresis
    • ≥ 90% reduction in serum M-protein and urine M-protein level < 100 mg/24 hours
  • Light Chain Only Myeloma (e.g., kappa or lambda only)
    • Serum and urine M-protein detectable by immunofixation but not on electrophoresis
    • ≥ 90% decrease in the difference between involved and uninvolved free light chain levels (applicable to Light Chain Only Myeloma)

Partial Response (PR)

Both of the following criteria must be met*:

  • Heavy Chain Myeloma (e.g., IgG kappa, IgG lambda, IgG only, etc.)
    • ≥ 50% reduction in serum M-protein
    • Reduction in 24-hour urinary M-protein by ≥ 90% or to < 200 mg/24 hours
  • Light Chain Only Myeloma (e.g., kappa or lambda only)
    • ≥ 50% reduction in serum M-protein
    • ≥ 50% decrease in the difference between the involved and uninvolved free light chain levels (applicable to Light Chain Only Myeloma)

Stable Disease (SD)

  • Does not meet the criteria for CR, VGPR, PR, or PD.

  • Stable Disease requires two consecutive assessments (by the same method) made at any time before the institution of any new therapy. If radiographic studies were performed, there must be no known evidence of new or progressive bone lesions. Radiographic studies are not required to satisfy SD requirements.

Progressive Disease (PD)

One or more of the following criteria must be met:

  • Heavy Chain Myeloma (e.g., IgG kappa, IgG lambda, IgG only, etc.)
    • Increase of ≥ 25% from the lowest response value achieved in one or more of the following:
      • Serum M-component with an absolute increase ≥ 0.5 g/dL (for progressive disease, serum M-component increases of ≥ 1 g/dL are sufficient if the starting M-component is ≥ 5 g/dL)
      • Urine M-component with an absolute increase ≥ 200 mg/24 hours
      • Bone marrow plasma cell percentage with an absolute increase of at least 10% plasma cells
    • Definite development of new bone lesions or soft tissue plasmacytomas, or definite increase in the size of any existing bone lesions or soft tissue plasmacytomas (≥ 50% increase from nadir in size of > 1 lesion, or a ≥ 50% increase in the longest diameter of a previous lesion > 1 cm in short axis); and/or
    • ≥ 50% increase in circulating plasma cells (minimum of 200 cells per µL) if this is the only measure of disease
  • Light Chain Only Myeloma (e.g., kappa or lambda only)
    • Increase of ≥ 25% from the lowest response value achieved in one or more of the following:
      • The difference between involved and uninvolved free light chain levels with an absolute increase > 10 mg/dL (applicable to Light Chain Only Myeloma)
      • Bone marrow plasma cell percentage with an absolute increase of at least 10% plasma cells
    • Definite development of new bone lesions or soft tissue plasmacytomas, or definite increase in the size of any existing bone lesions or soft tissue plasmacytomas (≥ 50% increase from nadir in size of >1 lesion, or a ≥ 50%
    • ≥ 50% increase in circulating plasma cells (minimum of 200 cells per µL) if this is the only measure of disease

If a patient has light chain only myeloma, has myeloma that can't be measured or is considered "non-secretory" which means the myeloma is not making a protein detectible in the blood, please refer to these criteria for treatment responses. 

 

 
Jennifer Ahlstrom
About the Author

Jennifer Ahlstrom - Jenny A - Myeloma survivor, patient advocate, wife, mom of 6. Believer that patients can help accelerate a cure by weighing in and participating in clinical trials. Founder of Myeloma Crowd, Myeloma Crowd Radio, HealthTree and the CrowdCare Foundation.

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