PLoS ONE (Jan 2014)

Preclinical evaluation of the novel, orally bioavailable Selective Inhibitor of Nuclear Export (SINE) KPT-335 in spontaneous canine cancer: results of a phase I study.

  • Cheryl A London,
  • Luis Feo Bernabe,
  • Sandra Barnard,
  • William C Kisseberth,
  • Antonella Borgatti,
  • Mike Henson,
  • Heather Wilson,
  • Kiersten Jensen,
  • Daisuke Ito,
  • Jaime F Modiano,
  • Misty D Bear,
  • Michael L Pennell,
  • Jean-Richard Saint-Martin,
  • Dilara McCauley,
  • Michael Kauffman,
  • Sharon Shacham

DOI
https://doi.org/10.1371/journal.pone.0087585
Journal volume & issue
Vol. 9, no. 2
p. e87585

Abstract

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BackgroundThe purpose of this study was to evaluate the activity of Selective Inhibitors of Nuclear Export (SINE) compounds that inhibit the function of the nuclear export protein Exportin 1 (XPO1/CRM1) against canine tumor cell lines and perform a Phase I clinical trial of KPT-335 in dogs with spontaneous cancer to provide a preliminary assessment of biologic activity and tolerability.Methods and findingsCanine tumor cell lines derived from non-Hodgkin lymphoma (NHL), mast cell tumor, melanoma and osteosarcoma exhibited growth inhibition and apoptosis in response to nanomolar concentrations of SINE compounds; NHL cells were particularly sensitive with IC50 concentrations ranging from 2-42 nM. A Phase I clinical trial of KPT-335 was performed in 17 dogs with NHL (naive or relapsed), mast cell tumor or osteosarcoma. The maximum tolerated dose was 1.75 mg/kg given orally twice/week (Monday/Thursday) although biologic activity was observed at 1 mg/kg. Clinical benefit (CB) including partial response to therapy (PR, n = 2) and stable disease (SD, n = 7) was observed in 9/14 dogs with NHL with a median time to progression (TTP) for responders of 66 days (range 35-256 days). A dose expansion study was performed in 6 dogs with NHL given 1.5 mg/kg KPT-335 Monday/Wednesday/Friday; CB was observed in 4/6 dogs with a median TTP for responders of 83 days (range 35-354 days). Toxicities were primarily gastrointestinal consisting of anorexia, weight loss, vomiting and diarrhea and were manageable with supportive care, dose modulation and administration of low dose prednisone; hepatotoxicity, anorexia and weight loss were the dose limiting toxicities.ConclusionsThis study provides evidence that the novel orally bioavailable XPO1 inhibitor KPT-335 is safe and exhibits activity in a relevant, spontaneous large animal model of cancer. Data from this study provides critical new information that lays the groundwork for evaluation of SINE compounds in human cancer.