Microbiological analysis from a phase 2 randomized study in adults evaluating single oral doses of gepotidacin in the treatment of uncomplicated urogenital gonorrhea caused by neisseria gonorrhoeae

Academic Article


  • We evaluated microbiological correlates for the successful treatment of Neisseria gonorrhoeae isolates from a phase 2 study of gepotidacin, a novel triazaacenaphthylene antibacterial, for therapy of uncomplicated urogenital gonorrhea. Culture, susceptibility testing, genotypic characterization, and frequency of resistance (FoR) were performed for selected isolates. Microbiological success was defined as culture-confirmed eradication of N. gonorrhoeae. Against 69 baseline urogenital isolates, gepotidacin MICs ranged from 0.06 to 1 g/ml (MIC90 0.5 g/ml). For gepotidacin, the ratio of the area under the free-drug concentration-time curve to the MIC (fAUC/MIC) was associated with therapeutic success. Success was 100% (61/ 61) at fAUC/MICs of 48 and decreased to 63% (5/8) for fAUC/MICs of 25. All 3 isolates from microbiological failures were ciprofloxacin resistant, had a baseline gepotidacin MIC of 1 g/ml, and carried a preexisting ParC D86N mutation, a critical residue for gepotidacin binding. In a test-of-cure analysis, the resistance to gepotidacin emerged in 2 isolates (MICs increased 32-fold) with additional GyrA A92T mutations, also implicated in gepotidacin binding. Test-of-cure isolates had the same sequence type as the corresponding baseline isolates. For 5 selected baseline isolates, all carrying a ParC D86N mutation, the in vitro FoR to gepotidacin was low (109 to 1010); the resistant mutants had the same A92T mutation as the 2 isolates in which resistance emerged. Five participants with isolates harboring the ParC D86N mutation were treatment successes. In summary, fAUC/MICs of 48 predicted 100% microbiological success, including 3 isolates with the ParC D86N mutation (fAUC/MICs 97). Pharmacokinetic/pharmacodynamic determinations may help to evaluate new therapies for gonorrhea; further study of gepotidacin is warranted. (This study has been registered at ClinicalTrials.gov under identifier NCT02294682.)
  • Authors

    Published In

    Digital Object Identifier (doi)

    Pubmed Id

  • 7949688
  • Author List

  • Scangarella-Oman NE; Hossain M; Dixon PB; Ingraham K; Min S; Tiffany CA; Perry CR; Raychaudhuri A; Dumont EF; Huang J
  • Volume

  • 62
  • Issue

  • 12