A simple prognostic system in patients with myelofibrosis undergoing allogeneic stem cell transplantation: A CIBMTR/EBMT analysis

To develop a prognostic model for patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HCT) for myelofibrosis (MF). We examined 623 patients undergoing allo-HCT between 2000 - 2016 in the USA (CIBMTR cohort). A Cox multivariable model was used to identify factors prognostic of mortality. A weighted score using these factors was assigned to patients transplanted in Europe (EBMT cohort) (n = 623). Age above 50 (hazard ratio [HR], 1.39; 95% confidence interval [CI], 0.98 -1.96), and HLA matched unrelated donor (HR, 1.29; 95% CI, 0.98-1.7) were associated with increased hazard of death and were assigned 1 point. Hemoglobin lower than 100g/L at time of transplant (HR, 1.63; 95% CI, 1.2- 2.19), and a mismatched unrelated donor (HR, 1.78; 95% CI, 1.25- 2.52), were assigned 2 points. The 3-year overall survival (OS) in patients with a low (1-2 points), intermediate (3-4 points) and high score (5 points) were 69% (95% CI, 61% -76 %), 51 % (95% CI, 46% -56.4 %), and 34% (95% CI, 21% - 49%), respectively (P. < 0.001). Increasing score was predictive of increased transplant related mortality (TRM) (P .0017) but not for relapse (P. 0.12). The derived score was predictive for OS (P. < 0.001) and TRM (P. 0.002) but not relapse (P. 17) in the EBMT cohort as well. The proposed system was prognostic of survival in two large cohorts, CIBMTR and EBMT, and can easily be applied by clinicians consulting patients with MF on transplant outcomes.