Researchers analyzed 805 patients age ≤70 years with primary myelofibrosis to determine the variables predictive of overall survival (OS), then incorporated them into two prognostic scoring systems, one based on clinical and genetic data (MIPSS70) and the other with clinical and genetic data plus cytogenetic information (MIPSS70-plus).
A multivariate analysis identified the following as significant risk factors for overall survival:
- Hemoglobin <100 g/L
- Leukocytes >25 × 109/L
- Platelets <100 × 109/L
- Circulating blasts ≥2%
- Bone marrow fibrosis grade ≥2
- Constitutional symptoms
- Absence of CALR type-1 mutation
- Presence of high-molecular risk mutation (i.e., ASXL1, EZH2, SRSF2, IDH1/2)
- Presence of two or more high-molecular risk mutations
By assigning hazard ratio (HR)-weighted points to these variables, the researchers delineated 3 risk categories for the MIPSS70 model: low-risk, intermediate-risk and high-risk, with 5-year OS of 95%, 70% and 29%, respectively.
In the MIPSS70-plus model, which included cytogenetic information, researchers delineated 4 risk categories, with 5-year OS of 91% (low-risk), 66% (intermediate-risk), 42% (high-risk) and 7% (very high-risk).
The researchers concluded that “MIPSS70 and MIPSS70-plus provide complementary systems of risk stratification for transplantation-age patients with primary myelofibrosis and integrate prognostically relevant clinical, cytogenetic and mutation data.”