Early bactericidal activity and pharmacokinetics of PA-824 in smear-positive tuberculosis patients

Antimicrob Agents Chemother. 2010 Aug;54(8):3402-7. doi: 10.1128/AAC.01354-09. Epub 2010 May 24.

Abstract

PA-824 is a novel nitroimidazo-oxazine being evaluated for its potential to improve tuberculosis (TB) therapy. This randomized study evaluated safety, tolerability, pharmacokinetics, and extended early bactericidal activity of PA-824 in drug-sensitive, sputum smear-positive, adult pulmonary tuberculosis patients. Fifteen patients per cohort received 1 of 4 doses of oral PA-824: 200, 600, 1,000, or 1,200 mg per day for 14 days. Eight subjects received once daily standard antituberculosis treatment as positive control. The primary efficacy endpoint was the mean rate of change in log CFU of Mycobacterium tuberculosis in sputum incubated on agar plates from serial overnight sputum collections, expressed as log10 CFU/day/ml (+/-standard deviation [SD]). The drug demonstrated increases that were dose linear but less than dose proportional in serum concentrations in doses from 200 to 1,000 mg daily. Dosing of 1,200 mg gave no additional exposure compared to 1,000 mg daily. The mean daily CFU fall under standard treatment was 0.148 (+/-0.055), consistent with that found in previous studies. The mean daily fall under PA-824 was 0.098 (+/-0.072) and was equivalent for all four dosages. PA-824 appeared safe and well tolerated; the incidence of adverse events potentially related to PA-824 appeared dose related. We conclude that PA-824 demonstrated bactericidal activity over the dose range of 200 to 1,200 mg daily over 14 days. Because maximum efficacy was unexpectedly achieved at the lowest dosage tested, the activity of lower dosages should now be explored.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Antitubercular Agents / administration & dosage
  • Antitubercular Agents / adverse effects
  • Antitubercular Agents / pharmacokinetics*
  • Antitubercular Agents / pharmacology*
  • Colony Count, Microbial
  • Culture Media
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Drug Administration Schedule
  • Female
  • Humans
  • Male
  • Mycobacterium tuberculosis / drug effects*
  • Nitroimidazoles / administration & dosage
  • Nitroimidazoles / adverse effects
  • Nitroimidazoles / pharmacokinetics*
  • Nitroimidazoles / pharmacology*
  • Sputum / microbiology
  • Treatment Outcome
  • Tuberculosis, Pulmonary / drug therapy*
  • Tuberculosis, Pulmonary / microbiology
  • Young Adult

Substances

  • Antitubercular Agents
  • Culture Media
  • Nitroimidazoles
  • pretomanid