According to the NCI website, Luspatercept is a soluble, recombinant fusion protein. Check for active clinical trials using this agent. (NCI Thesaurus)

According to WIKI Luspatercept is a drug for the treatment of anemia in beta thalassemia and myelodysplastic syndromes.

Link to Drug Information Portal, a service of the U.S. National Library of Medicine, National Institutes of Health
Link to National Cancer Institute

Wiki
Link to European Medicines Agency (EMEA)