Response criteria for ET
| . | Criteria . |
|---|---|
| Complete remission | |
| A | Durable* resolution of disease-related signs including palpable hepatosplenomegaly, large symptoms improvement,† AND |
| B | Durable* peripheral blood count remission, defined as: platelet count ≤400 ×109/L, WBC count <10 × 109/L, absence of leukoerythroblastosis, AND |
| C | Without signs of progressive disease, and absence of any hemorrhagic or thrombotic events, AND |
| D | Bone marrow histological remission defined as disappearance of megakaryocyte hyperplasia and absence of >grade 1 reticulin fibrosis. |
| Partial remission | |
| A | Durable* resolution of disease-related signs including palpable hepatosplenomegaly, and large symptoms improvement, AND |
| B | Durable* peripheral blood count remission, defined as: platelet count ≤400 × 109/L, WBC count <10 × 109/L, absence of leukoerythroblastosis, AND |
| C | Without signs of progressive disease, and absence of any hemorrhagic or thrombotic events, AND |
| D | Without bone marrow histological remission, defined as the persistence of megakaryocyte hyperplasia. |
| No response | Any response that does not satisfy partial remission |
| Progressive disease | Transformation into PV, post-ET myelofibrosis, myelodysplastic syndrome or acute leukemia‡ |
| . | Criteria . |
|---|---|
| Complete remission | |
| A | Durable* resolution of disease-related signs including palpable hepatosplenomegaly, large symptoms improvement,† AND |
| B | Durable* peripheral blood count remission, defined as: platelet count ≤400 ×109/L, WBC count <10 × 109/L, absence of leukoerythroblastosis, AND |
| C | Without signs of progressive disease, and absence of any hemorrhagic or thrombotic events, AND |
| D | Bone marrow histological remission defined as disappearance of megakaryocyte hyperplasia and absence of >grade 1 reticulin fibrosis. |
| Partial remission | |
| A | Durable* resolution of disease-related signs including palpable hepatosplenomegaly, and large symptoms improvement, AND |
| B | Durable* peripheral blood count remission, defined as: platelet count ≤400 × 109/L, WBC count <10 × 109/L, absence of leukoerythroblastosis, AND |
| C | Without signs of progressive disease, and absence of any hemorrhagic or thrombotic events, AND |
| D | Without bone marrow histological remission, defined as the persistence of megakaryocyte hyperplasia. |
| No response | Any response that does not satisfy partial remission |
| Progressive disease | Transformation into PV, post-ET myelofibrosis, myelodysplastic syndrome or acute leukemia‡ |
Molecular response is not required for assignment as complete response or partial response. Molecular response evaluation requires analysis in peripheral blood granulocytes. Complete response is defined as eradication of a preexisting abnormality. Partial response applies only to patients with at least 20% mutant allele burden at baseline. Partial response is defined as ≥50% decrease in allele burden.
WBC, white blood cell.
Lasting at least 12 wk.
Large symptom improvement (≥10-point decrease) in MPN-SAF TSS.10
For the diagnosis of PV see World Health Organization criteria (WHO)13 ; for the diagnosis of post-ET myelofibrosis, see the IWG-MRT criteria12 ; for the diagnosis of myelodysplastic syndrome and acute leukemia, see WHO criteria.13