Pharmacokinetic effect of AMD070, an Oral CXCR4 antagonist, on CYP3A4 and CYP2D6 substrates midazolam and dextromethorphan in healthy volunteers.


Journal Article

BACKGROUND:Many antiretroviral drugs used in HIV care involve complex drug metabolism by CYP3A4 and CYP2D6 enzymes, and drug interactions are problematic clinically. AMD070, a novel entry inhibitor, is an inhibitor of X4-tropic HIV virus. In vitro data suggested that it is a CYP3A4 substrate and may inhibit CYP2D6 and CYP3A4. METHODS:Twelve healthy subjects were given a single oral dose of 5 mg of midazolam and 30 mg of dextromethorphan on day 1 and 9, and 200 mg of AMD070 twice daily on days 2 through 9 (inclusive). Pharmacokinetic parameters of midazolam and dextromethorphan were assessed alone and in the presence of AMD070. RESULTS:The mean AUC0-24 and Cmax of dextromethorphan increased 2.86-fold (2.20 to 5.10, 90% confidence interval [CI]) and 2.52-fold (1.99 to 4.24, 90% CI), respectively, in the presence of AMD070. Plasma AUC0-12 of midazolam increased 1.33-fold (1.15 to 1.61, 90% CI) without change in Cmax. The half-life did not change for both drugs, but significant, parallel decrease in apparent oral clearance and volume of distribution was observed. CONCLUSIONS:The data support an alteration in bioavailability due to an AMD070-mediated inhibition of presystemic metabolism, though an intestinal P-glycoprotein effect could also be contributing. Interactions between AMD070 with CYP3A4 and, especially, 2D6 substrates of clinical importance in HIV care should be further explored.

Full Text

Duke Authors

Cited Authors

  • Nyunt, MM; Becker, S; MacFarland, RT; Chee, P; Scarborough, R; Everts, S; Calandra, GB; Hendrix, CW

Published Date

  • April 2008

Published In

Volume / Issue

  • 47 / 5

Start / End Page

  • 559 - 565

PubMed ID

  • 18362694

Pubmed Central ID

  • 18362694

Electronic International Standard Serial Number (EISSN)

  • 1944-7884

International Standard Serial Number (ISSN)

  • 1525-4135

Digital Object Identifier (DOI)

  • 10.1097/qai.0b013e3181627566


  • eng