Self-Study 2025 Release I: Myeloproliferative Neoplasms - A Focus on JAK Inhibitors in Myelofibrosis

Ruxolitinib was the first JAK (Janus kinase) inhibitor approved for the treatment of myelofibrosis (MF) in 2011. In the last five years, fedratinib, pacritinib, and momelotinib have become available. JAK inhibitors are associated with clinical benefit in patients with MF, largely related to reduction in spleen volume; however, patients may still experience significant cytopenias and eventual disease progression. The currently available JAK inhibitors exhibit different properties depending on their specific targets, which is relevant to clinical uses and adverse effect profiles. While research continues beyond JAK inhibitors to new targets, sequencing of these agents in the event of inadequate response or loss of response is an area of ongoing interest.