The Amelioration of Myelofibrosis with Thrombocytopenia by a JAK1/2 Inhibitor, Ruxolitinib, in a Post-polycythemia Vera Myelofibrosis Patient with a JAK2 Exon 12 Mutation

Intern Med. 2017;56(13):1705-1710. doi: 10.2169/internalmedicine.56.7871. Epub 2017 Jul 1.

Abstract

Less than 5% of patients with polycythemia vera (PV) show JAK2 exon 12 mutations. Although PV patients with JAK2 exon 12 mutations are known to develop post-PV myelofibrosis (MF) as well as PV with JAK2V617F, the role of JAK inhibitors in post-PV MF patients with JAK2 exon 12 mutations remains unknown. We describe how treatment with a JAK1/2 inhibitor, ruxolitinib, led to the rapid amelioration of marrow fibrosis, erythrocytosis and thrombocytopenia in a 77-year-old man with post-PV MF who carried a JAK2 exon 12 mutation (JAK2H538QK539L). This case suggests that ruxolitinib is a treatment option for post-PV MF in patients with thrombocytopenia or JAK2 exon 12 mutations.

Keywords: JAK2 exon 12 mutation; myelofibrosis; polycythemia vera; ruxolitinib; thrombocytopenia.

Publication types

  • Case Reports

MeSH terms

  • Aged, 80 and over
  • Exons
  • Humans
  • Janus Kinase 2 / antagonists & inhibitors
  • Janus Kinase 2 / genetics*
  • Male
  • Mutation
  • Nitriles
  • Polycythemia / genetics
  • Polycythemia / physiopathology
  • Polycythemia Vera / drug therapy*
  • Polycythemia Vera / genetics*
  • Primary Myelofibrosis / genetics
  • Primary Myelofibrosis / physiopathology
  • Pyrazoles / pharmacology
  • Pyrazoles / therapeutic use*
  • Pyrimidines
  • Thrombocytopenia / genetics
  • Thrombocytopenia / physiopathology

Substances

  • Nitriles
  • Pyrazoles
  • Pyrimidines
  • ruxolitinib
  • Janus Kinase 2