Safety and Efficacy of Reduced-Intensity Conditioning Allogeneic Hematopoietic Stem Cell Transplantation for Salvage Therapy of Myelofibrosis.

OBJECTIVE

To evaluate the efficacy and safety of reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (allo-HSCT) for a salvage therapy of patients with myelofibrosis (MF).

METHODS

We conducted a retrospective study of 17 MF patients with poor performance status, refractory disease, or progressive disease who underwent RIC-allo-HSCT. Overall survival (OS), progression-free survival (PFS), hematopoietic reconstitution, the cumulative incidence of relapse and improvements in myelofibrosis and splenomegaly were analyzed.

RESULTS

All 17 patients received RIC regimens. The neutrophil and platelet engraftment rates were 94.1% and 88.2%, respectively, with median engraftment times of 16 days (range, 11-22 days) and 22 days (range, 10-148 days). The cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) within 100 days post-transplant was 41.2%, and that of grade III-IV aGVHD was 17.6%. The overall incidence of chronic GVHD (cGVHD) was 35.3%. The reactivation rates of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) were 47.1% and 29.4%, respectively. Before transplantation, there were 10 patients (58.8%) with MF-3 and splenomegaly. At six months after transplantation, the proportion of MF-3 decreased to 26.7%, MF-0 increased to 40.0%, and the proportion of splenomegaly decreased to 53.3%. As of the follow-up date, the proportion of MF-3 had decreased to 21.4%, MF-0 had increased to 57.1%, and all eight remaining patients with splenomegaly had shown varying degrees of spleen size reduction. The estimated 1-year OS and PFS were 88.2% (95% CI, 60.6%-96.9%) and 81.9% (95% CI, 53.8%-93.8%), and the estimated 3-year OS and PFS were 70.6% (95% CI, 26.0%-91.4%) and 65.5% (95% CI, 25.7%-87.7%), respectively.

CONCLUSION

RIC-allo-HSCT is a feasible and effective alternative for salvage therapy in MF patients.