Currently, the treatments of anemia in patients with myeloproliferative neoplasms (MPNs) include blood transfusions (receiving red blood cells intravenously to replace the lack of functioning red blood cells), erythropoietin stimulating agents given as injections which will help stimulate red blood cell production in the bone marrow, and sometimes steroids. These interventions are supportive but are often insufficient and temporary as they are not capable of blocking the effects of the cancer cells causing anemia. 
   
The purpose of this study is to assess how well vactosertib works in MPNs to improve anemia. This study will also provide new information about how vactosertib blocks TGFβ signaling in MPN cells and how this, in turn, can block MPN cancer cells themselves and/or their ill-effects on the bone marrow such as fibrosis.

Vactosertib is considered investigational which means it has not yet been approved by the U.S. Food and Drug Administration (FDA). 

The the dose of vactosertib will be adjusted during the study to evaluate how well vactosertib works and to ensure that the dose used is not causing unexpected toxicities. The research team will monitor patients closely during the study. 

Total study participation will last between 6 months-1 year.