Criteria of clinical resistance and intolerance to hydroxyurea in PV based on the European LeukemiaNet consensus87
| Type . | Criteria . |
|---|---|
| Resistance | |
| 1 | Need for phlebotomy to keep Hct <45% after 3 months of ≥2 g/day of hydroxyurea, OR |
| 2 | Uncontrolled myeloproliferation, i.e., platelet count >400 × 109/L AND white blood cell count >10 × 109/L after 3 months of ≥2 g/day of hydroxyurea, OR |
| 3 | Failure to reduce massive* splenomegaly by more than 50% as measured by palpation, OR failure to completely relieve symptoms related to splenomegaly after 3 months of ≥2 g/day of hydroxyurea, OR |
| Intolerance | |
| 4 | Absolute neutrophil count <1.0 × 109/L OR platelet count <100 × 109/L or Hb <100 g/L at the lowest dose of hydroxyurea required to achieve a complete or partial clinico-hematological response†, OR |
| 5 | Presence of leg ulcers or other unacceptable hydroxyurea-related nonhematological toxicities, such as mucocutaneous manifestations, gastrointestinal symptoms, pneumonitis, or fever at any dose of hydroxyurea |
| Type . | Criteria . |
|---|---|
| Resistance | |
| 1 | Need for phlebotomy to keep Hct <45% after 3 months of ≥2 g/day of hydroxyurea, OR |
| 2 | Uncontrolled myeloproliferation, i.e., platelet count >400 × 109/L AND white blood cell count >10 × 109/L after 3 months of ≥2 g/day of hydroxyurea, OR |
| 3 | Failure to reduce massive* splenomegaly by more than 50% as measured by palpation, OR failure to completely relieve symptoms related to splenomegaly after 3 months of ≥2 g/day of hydroxyurea, OR |
| Intolerance | |
| 4 | Absolute neutrophil count <1.0 × 109/L OR platelet count <100 × 109/L or Hb <100 g/L at the lowest dose of hydroxyurea required to achieve a complete or partial clinico-hematological response†, OR |
| 5 | Presence of leg ulcers or other unacceptable hydroxyurea-related nonhematological toxicities, such as mucocutaneous manifestations, gastrointestinal symptoms, pneumonitis, or fever at any dose of hydroxyurea |
Organ extending by >10 cm from the LCM.
Complete response was defined as Hct <45% without phlebotomy, platelet count ≤400 × 109/L, white blood cell count ≤10 × 109/L, and no disease-related symptoms. Partial response was defined as: Hct <45% without phlebotomy, or response in three or more of the other criteria (European LeukemiaNet criteria).88