Current Challenges in Stem Cell Transplantation in Myelofibrosis

Primary or post-ET/PV myelofibrosis is one of the Philadelphia-negative myeloproliferative neoplasms with worst survival. Allogeneic stem cell transplantation (ASCT) can cure a substantial number of patients but is still not universally applicable due to toxicity which leads to therapy-related morbidity and mortality. In the more recent years, outcome of ASCT has improved by less toxic conditioning regimens and optimization of relapse prevention strategies. The introduction of novel therapies such as JAK2 inhibitors may also be helpful in preparation of the transplant by reducing spleen size and constitutional symptoms. To reduce the risk of relapse, molecular monitoring and adoptive immunotherapy with donor lymphocytes have been introduced. Despite lacking prospective randomized trials, it is justified to offer ASCT to eligible patients with PMF whose median survival is expected to be less than 5 years. This includes patients with intermediate-2 and high risk according to IPSS or DIPSS, respectively. The benefit/risk ratio should be considered in each patient taking also transplant- and patient-specific factors into account.