A phase II trial of tipifarnib in myelofibrosis: primary, post-polycythemia vera and post-essential thrombocythemia

Leukemia. 2007 Sep;21(9):1964-70. doi: 10.1038/sj.leu.2404816. Epub 2007 Jun 21.


Patients with primary myelofibrosis (PMF) or post-polycythemia vera or post-essential thrombocythemia myelofibrosis (post-PV/ET MF) have limited therapeutic options. The farnesyltransferase-inhibitor tipifarnib inhibits in vitro proliferation of myeloid progenitors from such patients. In the current phase II clinical trial, single-agent oral tipifarnib (300 mg twice daily x 21 of 28 days) was given to 34 symptomatic patients with either PMF (n=28) or post-PV/ET MF (n=6). Median time to discontinuation of protocol therapy was 4.6 months; reasons for early termination (n=19; 56%) included disease progression (21%) and adverse drug effects (18%). Toxicities (>/=grade 3) included myelosuppression (n=16), neuropathy (n=2), fatigue (n=1), rash (n=1) and hyponatremia (n=1). Response rate was 33% for hepatosplenomegaly and 38% for transfusion-requiring anemia. No favorable changes occurred in bone marrow fibrosis, angiogenesis or cytogenetic status. Pre- and post-treatment patient sample analysis for in vitro myeloid colony growth revealed substantial reduction in the latter. Clinical response did not correlate with either degree of colony growth, measurable decrease in quantitative JAK2(V617F) levels or tipifarnib IC(50) values (median 11.8 nM) seen in pretreatment samples. The current study indicates both in vitro and in vivo tipifarnib activity in PMF and post-PV/ET MF.

Publication types

  • Clinical Trial, Phase II
  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Aged, 80 and over
  • Anemia / drug therapy
  • Anemia / etiology
  • Antineoplastic Agents / administration & dosage*
  • Antineoplastic Agents / adverse effects
  • Bone Marrow / pathology
  • Female
  • Humans
  • Janus Kinase 2 / genetics
  • Male
  • Middle Aged
  • Polycythemia Vera / complications*
  • Polycythemia Vera / genetics
  • Primary Myelofibrosis / drug therapy*
  • Primary Myelofibrosis / etiology
  • Primary Myelofibrosis / genetics
  • Primary Myelofibrosis / pathology
  • Prospective Studies
  • Quinolones / administration & dosage*
  • Quinolones / adverse effects
  • Thrombocythemia, Essential / complications*
  • Thrombocythemia, Essential / genetics
  • Treatment Outcome


  • Antineoplastic Agents
  • Quinolones
  • JAK2 protein, human
  • Janus Kinase 2
  • tipifarnib