Prevention and treatment of transformation of myeloproliferative neoplasms to acute myeloid leukemia.

Philadelphia-chromosome negative (Ph-neg) myeloproliferative neoplasms (MPNs) are hematopoietic stem disorders with a risk of progression to the accelerated-phase (AP) or blastphase (BP) that is influenced by clinical, pathologic, cytogenetic, and molecular variables. Overall survival is limited in MPN-AP/BP with current treatment approaches, particularly in those patients that cannot receive an allogeneic hematopoietic stem cell transplant (allo-HCT). In addition, long-term survival with allo-HCT is predominantly seen in chronic-phase MPNs which suggests that the ideal time for intervention may be before MPNs evolve to AP/BP. Over the course of this review we will focus on the risk factors for progression to MPN-AP/BP, identification of high-risk chronic-phase MPNs, potential early-intervention strategies, and considerations around the timing of allo-HCT. We will also summarize current survival outcomes in MPN-AP/BP, discuss the uncertainty around how to best gauge response to therapy, and outline clinical trial considerations for this patient population. Lastly, we will highlight future directions in the management of high-risk MPNs.