Haplo-identical Transplantation in Patients With Myelofibrosis - A Phase 2 Prospective Multicentric Prospective Study

Overview

The only curative treatment in patients with primary or secondary myelofibrosis is allogeneic hematopoietic stem cells (HSCT). It has been reported that intermediate and higher risk patients according to international prognostic scores benefit from HSCT in terms of survival (Kröger et al, 2015). In 2013, we conducted in France a prospective trial testing the use of ruxolitinib before transplantation ("JAK-ALLO study" NCT01795677). Outcome of patients was better in patients transplanted with a matched sibling donor than an unrelated donor confirming other studies (Kröger et al, 2009; Rondelli et al, 2014). In the JAK-ALLO trial, acute GVHD incidence was high, often hyperacute and severe. Recently, the EBMT group has reported a registry study on familial haplo-identical transplantation (haplo) in patients with myelofibrosis (Raj et al, 2018). Post-transplant cyclophosphamide was used in 59% of cases. One-year overall survival (OS) and disease-free survival (DFS) were 61 and 58% which favorably compared to outcome after unrelated transplantation. Genova team has also reported impressive results after haplo-identical transplantation in their center (Bregante et al, 2015). Bregante et al have reported outcome of 2 cohorts transplanted from 2000 to 2010 and from 2011 to 2014. The main difference between the 2 periods is the more frequent use of haplo in the second period (54% versus 5%). Outcome was much better in the second period with OS at 70% versus 49% and authors suggest that this improvement is related to the best outcome among haplo transplantation. The improvement of outcome after haplo has been attributed to a better GVHD prophylaxis, especially with the use of post-transplant cyclophosphamide. Given the poor outcome after unrelated transplantation and especially in HLA mismatched unrelated setting and encouraging results in family haplo identical transplantation, this current study proposes to test haplo-identical transplantation in myelofibrosis patients without a matched related donor. The main objective of this study is disease and rejection-free survival one year after haplo-identical transplantation in patients with primary or secondary myelofibrosis.