At the 20th Congress of the European Hematology Association (EHA), Claire Harrison, MD, DM, FRCP, FRCPath, of Guy’s and St Thomas’ NHS Foundation Trust, London, UK, discusses the results of the phase 3 PERSIST-1 trial, which compared the efficacy and safety of pacritinib, a Janus kinase 2 inhibitor, versus best available therapy in patients with primary myelofibrosis, post-polycythemia vera myelofibrosis or post-essential thrombocythemia myelofibrosis.