WILMINGTON, Del.--(BUSINESS WIRE)--Incyte (Nasdaq:INCY) today announced that the U.S. Food and Drug Administration (FDA) has approved Jakafi XR™ (ruxolitinib) extended-release tablets for the treatment of adults with intermediate- or high-risk myelofibrosis (MF); adults with polycythemia vera (PV) who have had an inadequate response to or are intolerant of hydroxyurea; as well as adults and children aged 12 years and older with steroid-refractory acute graft-versus-host disease (GVHD) or chroni.