A phase I study of oral ixabepilone in patients with advanced solid tumors

John F. Deeken, John L. Marshall, Michael J. Pishvaian, Jimmy Hwang, Christoph M. Ahlers, Pamela L. Clemens, Susan M. Parker, Lisa Iacono, Patricia M. LoRusso

Research output: Contribution to journalArticlepeer-review


Background: Intravenous infusion of ixabepilone is Food and Drug Administration-approved for treatment of patients with metastatic breast cancer. The aim of this study was to establish the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), safety, and pharmacokinetics (PK) of a novel oral formulation of ixabepilone in patients with advanced solid tumors. Patients and methods: Forty-four patients received one of six daily doses of oral ixabepilone (5, 10, 15, 20, 25, or 30 mg) on days 1-5 of a 21-day cycle. PK parameters were evaluated in cycle 1 for all treated patients and in cycle 1 and cycle 2 for patients participating in assessments of food and gastric pH effects. Results: The most common DLTs (reported in at least one patient) were neutropenia, neutropenic fever, diarrhea, ileus, and hypokalemia. The MTD of oral ixabepilone was 25 mg. Plasma concentrations of ixabepilone showed high variability; coefficients of variation for the area under the curve and the peak plasma concentration ranged from 61 to 131 % and from 17 to 172 %, respectively. The mean half-life of ixabepilone calculated after day 5 of cycle 1 ranged from 24 to 47 h. Ixabepilone exposure was higher when administered with a low-fat meal compared with the fasted state, and when administered 2 h after the histamine H2 receptor antagonist famotidine. Conclusions: The MTD of oral ixabepilone when administered once daily for five consecutive days every 21 days was 25 mg. Ixabepilone exposure was highly variable; therefore, safety and efficacy of this novel oral formulation might not be reliably predicted.

Original languageEnglish (US)
Pages (from-to)1071-1078
Number of pages8
JournalCancer Chemotherapy and Pharmacology
Issue number5
StatePublished - May 2014
Externally publishedYes


  • Advanced solid tumors
  • Ixabepilone
  • Oral
  • Pharmacokinetics

ASJC Scopus subject areas

  • Oncology
  • Toxicology
  • Pharmacology
  • Cancer Research
  • Pharmacology (medical)


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