title: Preclinical testing of the nitroimidazopyran PA-824 for activity against Mycobacterium tuberculosis in a series of in vitro and in vivo models.
abstract: This study extends earlier reports regarding the in vitro and in vivo efficacies of the nitroimidazopyran PA-824 against Mycobacterium tuberculosis. PA-824 was tested in vitro against a broad panel of multidrug-resistant clinical isolates and was found to be highly active against all isolates (MIC<1 microg/ml). The activity of PA-824 against M. tuberculosis was also assessed grown under conditions of oxygen depletion. PA-824 showed significant activity at 2, 10, and 50 microg/ml, similar to that of metronidazole, in a dose-dependent manner. In a short-course mouse infection model, the efficacy of PA-824 at 50, 100, and 300 mg/kg of body weight formulated in methylcellulose or cyclodextrin/lecithin after nine oral treatments was compared with those of isoniazid, rifampin, and moxifloxacin. PA-824 at 100 mg/kg in cyclodextrin/lecithin was as active as moxifloxacin at 100 mg/kg and isoniazid at 25 mg/kg and was slightly more active than rifampin at 20 mg/kg. Long-term treatment with PA-824 at 100 mg/kg in cyclodextrin/lecithin reduced the bacterial load below 500 CFU in the lungs and spleen. No significant differences in activity between PA-824 and the other single drug treatments tested (isoniazid at 25 mg/kg, rifampin at 10 mg/kg, gatifloxacin at 100 mg/kg, and moxifloxacin at 100 mg/kg) could be observed. In summary, its good activity in in vivo models, as well as its activity against multidrug-resistant M. tuberculosis and against M. tuberculosis isolates in a potentially latent state, makes PA-824 an attractive drug candidate for the therapy of tuberculosis. These data indicate that there is significant potential for effective oral delivery of PA-824 for the treatment of tuberculosis.
authors.affiliation: Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA. lenaerts@colostate.edu
authors.forename: Anne J
authors.initials: AJ
authors.lastname: Lenaerts
authors.forename: Veronica
authors.initials: V
authors.lastname: Gruppo
authors.forename: Karen S
authors.initials: KS
authors.lastname: Marietta
authors.forename: Christine M
authors.initials: CM
authors.lastname: Johnson
authors.forename: Diane K
authors.initials: DK
authors.lastname: Driscoll
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Tompkins
authors.forename: Jerry D
authors.initials: JD
authors.lastname: Rose
authors.forename: Robert C
authors.initials: RC
authors.lastname: Reynolds
authors.forename: Ian M
authors.initials: IM
authors.lastname: Orme
mesh_terms: D000818:Animals; D000995:Antitubercular Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D015169:Colony Count, Microbial; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D005260:Female; D006801:Humans; D008168:Lung / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D009593:Nitroimidazoles / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000382:microbiology; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy* / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D009593:Nitroimidazoles; C410767:pretomanid