Pre-Transplant JAK Inhibitor Use Predicts Post-Transplant Survival in Patients With Myelofibrosis

A study published in the European Journal of Hematology evaluated the effects of various patient and clinical factors on survival outcomes in 89 patients with myelofibrosis who had undergone allogeneic cell transplantation (allo-HCT). Participants had allo-HCT between 2005 and 2018.

Of this group, 54% of patients had received JAK1/2 inhibitors prior to transplant. The median CD34 count was 7.1×106 cells/kg.

Graft failure was seen in 10% patients. In addition, 24% of patients experienced grade 3-4 acute graft-versus-host (GVHD) and 40% experienced moderate/severe chronic GVHD. Rates of two-year overall survival (OS) and relapse-free survival (RFS) were 51% and 43%, respectively. The cumulative incidences of relapse (CIR) and non-relapse mortality (NRM) at two years were 11% and 46%, respectively.

Looking at factors associated with survival outcomes, the researchers found that higher CD34 cell dose (≤5 vs. 5-9 or ≥9×106 cells/kg) and lower pre-HCT ferritin (≤1,000 ng/ml) were associated with better OS, RFS, and lower NRM. Development of grade 3-4 acute GVHD was associated with higher NRM. Use of pre-transplant JAK inhibitors was associated with lower incidence of grade 3-4 acute GVHD.

Together, these findings suggest that higher CD34 cell dose and pre-transplant JAK inhibition is associated with reduced risk of severe acute GVHD. “These two modifiable parameters should be considered during allo-HCT for MF,” the researchers concluded.