Effect of pre‐transplant JAK1/2 inhibitors and CD34 dose on transplant outcomes in myelofibrosis. (27th July 2021) - Cyriac, Sunu
Abstract: Allogeneic hematopoeitic cell transplantation (allo‐HCT) is the only curative treatment for myelofibrosis (MF). We evaluate the impact of various factors on survival outcomes post‐transplant in MF. Data of 89 consecutive MF patients (primary 47%) who underwent allo‐HCT between 2005 and 2018 was evaluated. Fifty‐four percent patients had received JAK1/2 inhibitors (JAKi) pre‐HCT. The median CD34 count was 7.1x10 6 cells/kg. Graft failure was seen in 10% of the patients. Grade 3‐4 acute GVHD (aGVHD) and moderate/severe chronic graft versus host disease (cGVHD) occurred in 24% and 40% patients, respectively. Two‐year overall survival (OS) and relapse free survival (RFS) were 51% and 43%, respectively. Cumulative incidence of relapse (CIR) and non‐relapse mortality (NRM) at 2 years were 11% and 46%, respectively. Higher CD34 cell dose (≤5 × 10 6 cells/kg vs 5‐9 or ≥9 × 10 6 cells/kg) and lower pre‐HCT ferritin (</=1000 ng/ml) were associated with better OS, RFS and lower NRM. Grade 3‐4 aGVHD was associated with higher NRM. Use of pre‐transplant JAKi was associated with lower incidence of grade 3‐4 aGVHD. In summary, higher CD34 cell dose is associated with better allo‐HCT outcomes in MF and pre‐HCT JAKi use is associated with reduced risk of severe aGVHD. These two modifiable parameters should be considered during allo‐HCT for MF.