Evaluation of the effect of Naloxegol on cardiac repolarization: a randomized, placebo- and positive-controlled crossover thorough QT/QTc study in healthy volunteers

Clin Ther. 2013 Dec;35(12):1876-83. doi: 10.1016/j.clinthera.2013.09.019. Epub 2013 Nov 13.


Background: Opioid-induced constipation (OIC) is a common adverse effect associated with opioid use. Naloxegol is a PEGylated derivative of naloxone in clinical development as a once-daily oral treatment of OIC.

Objectives: A thorough QT/QTc study was conducted, according to International Conference on Harmonisation E14 guidelines, to characterize the effect of naloxegol on cardiac repolarization.

Methods: In this randomized, positive- and placebo-controlled crossover study, healthy men received a single dose of naloxegol 25 mg (therapeutic dose), naloxegol 150 mg (supratherapeutic dose), moxifloxacin 400 mg (positive control), or placebo in 1 of 4 sequences (Williams Latin square design). The washout time between treatment periods was at least 5 days. Digital 12-lead ECGs were recorded at baseline and at 10 time points over 24 hours after dosing in each treatment period. QT intervals were corrected for heart rate using the Fridericia formula (QTcF) and the Bazett formula (QTcB).

Results: A total of 52 subjects were enrolled (mean age, 28 years), and 45 received all 4 treatments. The placebo-corrected, baseline-adjusted, mean increases in QTcF with naloxegol 25 and 150 mg were both <5 msec at each time point, and all upper limits of the 2-sided 90% CI were <10 msec. Similar findings were observed using QTcB; the upper limits of the 2-sided 90% CI were <10 msec at all time points after dosing with naloxegol 25 or 150 mg. With moxifloxacin 400 mg, mean QTcF was increased by a maximum of 11.1 msec (90% CI, 9.3-12.9 msec), supporting assay sensitivity.

Conclusion: Naloxegol at 25 and 150 mg was not associated with QT/QTc interval prolongation in these healthy men, and at the proposed therapeutic dose of 25 mg/d, naloxegol is not expected to have a clinically relevant effect on cardiac repolarization in patients with OIC. ClinicalTrials.gov identifier: NCT01325415.

Keywords: cardiac repolarization; electrocardiography; naloxegol; opioid antagonist; opioid-induced constipation; peripheral µ-opioid receptor antagonist.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aza Compounds / administration & dosage
  • Aza Compounds / adverse effects
  • Aza Compounds / pharmacokinetics
  • Constipation / chemically induced
  • Constipation / drug therapy
  • Cross-Sectional Studies
  • Dose-Response Relationship, Drug
  • Drug Administration Schedule
  • Electrocardiography / drug effects
  • Fluoroquinolones
  • Healthy Volunteers
  • Heart / drug effects*
  • Heart Rate / drug effects*
  • Humans
  • Male
  • Middle Aged
  • Morphinans / administration & dosage*
  • Morphinans / adverse effects
  • Morphinans / pharmacokinetics
  • Moxifloxacin
  • Naloxone / administration & dosage*
  • Naloxone / adverse effects*
  • Naloxone / pharmacokinetics
  • Narcotic Antagonists / administration & dosage*
  • Narcotic Antagonists / adverse effects*
  • Narcotic Antagonists / pharmacokinetics
  • Polyethylene Glycols / administration & dosage*
  • Polyethylene Glycols / adverse effects
  • Polyethylene Glycols / pharmacokinetics
  • Quinolines / administration & dosage
  • Quinolines / adverse effects
  • Quinolines / pharmacokinetics
  • Young Adult


  • Aza Compounds
  • Fluoroquinolones
  • Morphinans
  • Narcotic Antagonists
  • Quinolines
  • Naloxone
  • Polyethylene Glycols
  • naloxegol
  • Moxifloxacin

Associated data

  • ClinicalTrials.gov/NCT01325415