MPN Response Criteria1

CR (requires each of the following)

Requires all of the following maintained for a minimum of 12 weeks. When reporting the CR achievement date, report the first date when CR was achieved (not the 12 week date in which CR was maintained).

  • Bone marrow with ≤ 5% myeloblasts (including monocytic blast equivalents in CMML) with normal maturation of all cell lines and return to normal cellularity
  • Myelofibrosis absent or ≤ grade 1 fibrosis (mild reticulin fibrosis)
  • Peripheral blood counts showing:
    • WBC ≤ 10 × 109/L
    • Hgb ≥ 11 g/dL
    • PLT ≥ 100 × 109/L; ≤ 450 × 109/L
    • Blasts 0%
    • Neutrophilic precursors reduced to ≤ 2%
    • Monocytes ≤ 1 × 109/L
  • Resolution of any extramedullary disease present prior to therapy; this includes cutaneous disease, disease-related serous effusions, and palpable hepatosplenomegaly

Myelofibrosis CR2

Requires all of the following maintained for a minimum of 12 weeks. When reporting the CR achievement date, report the first date when CR was achieved (not the 12 week date in which CR was maintained).

  • Bone marrow with ≤ 5% myeloblasts with normal maturation of all cell lines
  • Myelofibrosis absent or ≤ grade 1 fibrosis (mild reticulin fibrosis)
  • Peripheral blood counts showing:
    • ANC ≥ 1.0 × 109/L and < upper limit of normal
    • Hgb ≥ 11 g/dL and < upper limit of normal
    • PLT ≥ 100 × 109/L and < upper limit of normal
    • Neutrophilic precursors reduced to ≤ 2%
  • Resolution of disease symptoms and no palpable hepatosplenomegaly; no evidence of extramedullary hematopoiesis

Partial Response

Requires all of the following maintained for a minimum of 12 weeks. When reporting the date when partial response was achieved, report the first date when the criteria for partial response was met (not the 12 week date in which partial response was maintained).

  • Peripheral blood counts showing:
    • ANC ≥ 1.0 × 109/L and < upper limit of normal
    • Hgb ≥ 10.0 g/dL and < upper limit of normal
    • PLT ≥ 100 × 109/L and < upper limit of normal
    • Neutrophilic precursors reduced to ≤ 2%
  • Resolution of disease symptoms and no palpable hepatosplenomegaly; no evidence of extramedullary hematopoiesis

or

  • Bone marrow with ≤ 5% myeloblasts with normal maturation of all cell lines
  • Myelofibrosis absent or ≤ grade 1 fibrosis (mild reticulin fibrosis)
  • Peripheral blood counts showing:
    • ANC ≥ 1.0 × 109/L and < upper limit of normal
    • Hgb ≥ 8.5 g/dL but <10.0 g/dL and < upper limit of normal
    • PLT ≥ 50 × 109/L but <100 × 109/L and < upper limit of normal
    • Neutrophilic precursors reduced to ≤ 2%
  • Resolution of disease symptoms and no palpable hepatosplenomegaly; no evidence of extramedullary hematopoiesis

Clinical Improvement

Requires all of the following maintained for a minimum of 12 weeks. When reporting the date when clinical improvement was achieved, report the first date when the criteria for clinical improvement was met (not the twelve-week date in which clinical improvement was maintained).

  • The achievement of any of the following responses without progressive disease or increase in severity of anemia, thrombocytopenia, or neutropenia
    • Anemia Response
      • Transfusion-independent patients: a ≥ 2.0 g/dL increase in hemoglobin level
      • Transfusion-dependent patients: becoming transfusion independent
    • Spleen Response
      • A baseline splenomegaly that is palpable at 5-10 cm, below the LCM, becomes not palpable or
      • A baseline splenomegaly that is palpable at > 10 cm, below the LCM, decreases by ≥ 50%
      • A baseline splenomegaly that is palpable at < 5 cm, below the LCM, is not eligible for spleen response
      • A spleen response requires confirmation by MRI or computed tomography showing ≥ 35% spleen volume reduction
    • Symptoms Response
      • A ≥ 50% reduction in the MPN-SAF TSS

Stable disease

  • Does not meet any of the other response categories

Progressive Disease

  • Appearance of a new splenomegaly that is palpable at least 5 cm below the LCM or
  • A ≥ 100% increase in palpable distance, below LCM, for baseline splenomegaly of 5-10 cm or
  • A 50% increase in palpable distance, below LCM, for baseline splenomegaly of > 10 cm or
  • Leukemic transformation confirmed by a bone marrow blast count of ≥ 20% or
  • A peripheral blood blast content of ≥ 20% associated with an absolute blast count of ≥ 1 × 109/L that lasts for at least 2 weeks

Relapse from CR

  • No longer meeting criteria for at least CI after achieving CR, PR, or CI, or
  • Loss of anemia response persisting for at least 1 month or
  • Loss of spleen response persisting for at least 1 month

1 Savona, M. R., Malcovati, L., Komrokji, R., Tiu, R. V., Mughal, T. I., Orazi, A., … & List, A. F. (2015). An international consortium proposal of uniform response criteria for myelodysplastic/myeloproliferative neoplasms (MDS/MPN) in adults. Blood, 125(12), 1857-1865.

2 Tefferi, A., Cervantes, F., Mesa, R., Passamonti, F., Verstovsek, S., Vannucchi, A. M., … & Barosi, G. (2013). Revised response criteria for myelofibrosis: international Working Group-Myeloproliferative Neoplasms Research and Treatment (IWG-MRT) and European LeukemiaNet (ELN) consensus report. Blood, 122(8), 1395-1398.

Manual Updates:
Sections of the Forms Instruction Manual are frequently updated. The most recent updates to the manual can be found below. For additional information, select the manual section and review the updated text.

If you need to reference the historical Manual Change History for this form, please click here or reference the retired manual section on the Retired Forms Manuals webpage.

Date Manual Section Add/Remove/Modify Description
8/19/2020 MPN Response Criteria Modify Updated the response criteria for CR, Myelofibrosis CR, Partial Response, and Clinical Improvement by adding in clarification to report the first date in which the disease status was achieved, not the 12 week date in the disease status was maintained. See the following example for CR: When reporting the CR achievement date, report the first date when CR was achieved (not the 12 week date in which CR was maintained).
7/9/2020 MPN Response Criteria Modify Updated the response criteria for CR, Myelofibrosis CR, Partial Response, and Clinical Improvement by adding in the following: Requires all of the following maintained for a minimum of 12 weeks
5/10/2020 MPN Response Criteria Add Separated the MPN response criteria to align with the new MPN disease-specific forms.
Last modified: Aug 19, 2020

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