Pacritinib is a kinase inhibitor with activity against Janus-associated kinase 2 (JAK2) and Fms-like receptor tyrosine kinase 3 (FLT3). Pacritinib inhibits both wild-type JAK2 and the JAK2V617F mutant form that is common in patients with myeloproliferative neoplasms. Pacritinib also exhibits inhibitory activity against additional cellular kinases (such as colony-stimulating factor 1 and interleukin 1 receptor-associated kinase 1), the clinical relevance of which is unknown.