Incidence and risk factors for graft failure after allogeneic hematopoietic stem cell transplantation in patients with myelofibrosis.

Graft failure (GF) is a barrier to successful allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with myelofibrosis (MF). We investigated the incidence, risk factors, and prognosis for GF after allo-HSCT for MF. Two hundred and eleven patients with MF who underwent allo-HSCT across 32 hematology centers in China between December 2008 and December 2024 were retrospectively analyzed. Among them, 66 underwent matched sibling donor HSCT, 127 haploidentical HSCT, and 18 unrelated donor HSCT. The overall GF incidence was 12.5%. GF incidence was significantly associated with donor type (matched sibling, 4.8%; alternative, 13.3%; P = 0.024). Pretransplant massive splenomegaly increased GF incidence (non-massive splenomegaly, 8.5%; massive, 18.5%; P = 0.034). In multivariate analysis, massive splenomegaly (HR = 3.047; P = 0.007) and alternative donors (HR = 3.528; P = 0.041) increased GF risk. With median follow-up of 734 days, 3-year OS, DFS, relapse rate and NRM was 65.5%, 60.8%, 10.1% and 27.8%, respectively. Multivariate analysis showed pretransplant splenomegaly reduced 3-year DFS (HR = 1.671; P = 0.025), and alternative donors reduced 3-year OS (HR = 2.033; P = 0.015). In conclusion, Allo-HSCT provides curative outcomes for MF patients. However, GF remains a significant challenge, particularly in haploidentical HSCT and those with massive pretransplant splenomegaly.