Outcomes following second allogeneic haematopoietic cell transplantation in patients with myelofibrosis: a retrospective study of the Chronic Malignancies Working Party of EBMT.

Therapeutic management of patients with primary or secondary myelofibrosis (MF) who experience relapse or graft failure following allogeneic haematopoietic cell transplantation (allo-HCT) remains heterogeneous. We retrospectively analyzed 216 patients undergoing a second allo-HCT for either relapse (56%) or graft failure (31%) between 2010 and 2017. Median age was 57.3 years (range 51-63). The same donor as for the first allo-HCT was chosen in 66 patients (31%) of whom 19 received an HLA-identical sibling donor, whereas a different donor was chosen for 116 patients (54%). Median follow-up was 40 months. Three-year overall survival (OS) and relapse-free survival (RFS) were 42% and 39%, respectively. Three-year non-relapse mortality (NRM) and relapse rates were 36% and 25%, respectively. Grade II-IV and III-IV acute GVHD occurred in 25% and 11% of patients, respectively, and the 3-year incidence of chronic GVHD was 33% including 14% for extensive grade. Graft-failure incidence at 1 year was 14%. In conclusion, our data suggest that a second allo-HCT is a potential option for patients failing first allo-HCT for MF albeit careful patient assessment is fundamental to identify individual patients who could benefit from this approach.