The development, safety and efficacy of pacritinib for the treatment of myelofibrosis

Expert Rev Anticancer Ther. 2016 Nov;16(11):1101-1108. doi: 10.1080/14737140.2016.1233061. Epub 2016 Sep 21.


Dysregulation of janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway has been described in myelofibrosis (MF). Currently, there is an unmet need for agents that have the benefit of JAK inhibition, yet also are safe and effective in patients with thrombocytopenia. Areas covered: We discuss the various preclinical and clinical studies describing pacritinib, a selective JAK2/FLT3 inhibitor. So far, it has shown promising results, without significant thrombocytopenia. A PubMed search, using keywords 'pacritinib', 'SB 1518' and 'myelofibrosis' was conducted. Published abstracts from recent national and international meetings were also reviewed for unpublished data. Expert commentary: Currently, pacritinib is on hold by Food and Drugs Administration. It would be imperative to understand if there is a treatment related toxicity that would limit its use. If a safe path is found for this agent, it could have a significant benefit in various settings, based on the data so far.

Keywords: Anemia; JAK2 inhibitor; Myelofibrosis; Pacritinib; Thrombocytopenia.

Publication types

  • Review

MeSH terms

  • Animals
  • Bridged-Ring Compounds / adverse effects
  • Bridged-Ring Compounds / pharmacology
  • Bridged-Ring Compounds / therapeutic use*
  • Drug Design
  • Humans
  • Janus Kinase 2 / antagonists & inhibitors
  • Primary Myelofibrosis / drug therapy*
  • Primary Myelofibrosis / physiopathology
  • Protein Kinase Inhibitors / adverse effects
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use*
  • Pyrimidines / adverse effects
  • Pyrimidines / pharmacology
  • Pyrimidines / therapeutic use*
  • fms-Like Tyrosine Kinase 3 / antagonists & inhibitors


  • 11-(2-pyrrolidin-1-ylethoxy)-14,19-dioxa-5,7,26-triazatetracyclo(,6).1(8,12))heptacosa-1(25),2(26),3,5,8,10,12(27),16,21,23-decaene
  • Bridged-Ring Compounds
  • Protein Kinase Inhibitors
  • Pyrimidines
  • FLT3 protein, human
  • fms-Like Tyrosine Kinase 3
  • JAK2 protein, human
  • Janus Kinase 2