Allogeneic hematopoietic stem cell transplantation for primary and secondary myelofibrosis

a retrospective, multicenter study of the Kanto Study Group for Cell Therapy (KSGCT)

Abstract

The optimal candidates and timing for allogeneic stem cell transplantation (allo-SCT) in patients with primary myelofibrosis (PMF) and secondary myelofibrosis (sMF) are unknown. We retrospectively examined the outcomes of PMF (n=13) and sMF (n=8)patients who underwent allo-SCT between 1997 and 2008. The median age at transplantation was 50 years (range, 21-60). Thirteen subjects (61.9%) received myeloablative conditioning. The source of hematopoietic cells was HLA-matched related (52.3%), -matched unrelated (33.3%), or -mismatched unrelated (9.5%) donors. All patients achieved engraftment, and the median time to neutrophil and platelet recovery was 19 (range, 13-36) and 75 (range, 15-411) days, respectively. With a median follow-up of 16.7(range, 1-134) months, overall survival (OS) at 60 months was 55.6% (95% CI, 34.0-77.0%). No significant differences in OS were observed between PMF and sMF patients and between myeloablative and reduced-intensity conditioning. HLA-mismatched donors, lower platelet count (<10×10 ⁴ /μl), and previous blastic transformation were associated with a significantly worse prognosis. These data suggest that allo-SCT with myeloablative or reduced-intensity conditioning is potentially effective for PMF and sMF patients aged <60 years. However, a platelet count of <10×10 ⁴ /μl is a strong adverse factor.