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BackgroundIn this phase 2 study, we evaluated the efficacy and safety of oral gepotidacin, a novel triazaacenaphthylene bacterial type II topoisomerase inhibitor, for the treatment of uncomplicated urogenital gonorrhea.MethodsAdult participants with suspected urogenital gonorrhea were enrolled and completed baseline (day 1) and test-of-cure (days 4-8) visits. Pretreatment and posttreatment urogenital swabs were collected for Neisseria gonorrhoeae (NG) culture and susceptibility testing. Pharyngeal and rectal swab specimens were collected if there were known exposures. Participants were stratified by gender and randomized 1:1 to receive a 1500-mg or 3000-mg single oral dose of gepotidacin.ResultsThe microbiologically evaluable population consisted of 69 participants, with NG isolated from 69 (100%) urogenital, 2 (3%) pharyngeal, and 3 (4%) rectal specimens. Microbiological eradication of NG was achieved by 97%, 95%, and 96% of participants (lower 1-sided exact 95% confidence interval bound, 85.1%, 84.7%, and 89.1%, respectively) for the 1500-mg, 3000-mg, and combined dose groups, respectively. Microbiological cure was achieved in 66/69 (96%) urogenital infections. All 3 failures were NG isolates that demonstrated the highest observed gepotidacin minimum inhibitory concentration of 1 µg/mL and a common gene mutation. At the pharyngeal and rectal sites, 1/2 and 3/3 NG isolates, respectively, demonstrated microbiological cure. There were no treatment-limiting adverse events for either dose.ConclusionsThis study demonstrated that single, oral doses of gepotidacin were ≥95% effective for bacterial eradication of NG in adult participants with uncomplicated urogenital gonorrhea.Clinical trials registrationNCT02294682.

Background: Gepotidacin is a novel, first-in-class triazaacenaphthylene antibiotic that inhibits bacterial DNA replication by a distinct mechanism of action and is active against most strains of Neisseria gonorrhoeae (N. gonorrhoeae). Phase II data suggested higher exposures were needed for efficacy and to suppress resistance development. A translational approach using in vitro pharmacokinetic/pharmacodynamic (PK/PD) and clinical data was used to select a gepotidacin dose for a phase III study. In this narrative review of previously shown data, we summarise how a translational approach based on in vitro PK/PD and population PK modelling and simulation data was undertaken to select a dosing regimen for the ongoing phase III gepotidacin study in participants with uncomplicated urogenital gonorrhoea.Methods: For dose selection, prior in vitro minimum inhibitory concentrations (MICs) and PK/PD data were available. PK modelling was conducted to determine a dose that would limit plasma concentrations to less than 14 µg/mL (as concentrations above this are associated with QT prolongation and effects associated with acetylcholinesterase inhibition) while maintaining ≥90% probability of target attainment (PTA) for efficacy and resistance suppression against N. gonorrhoeae isolates with gepotidacin MICs ≤1 µg/mL.Results: Two 3000 mg gepotidacin doses, administered 10-12 hours apart, resulted in PTA of ≥97.5% and ≥91.7% for gepotidacin MICs ≤1 µg/mL for the ratio of the area under the free drug plasma concentration-time curve over 24 hours to the MIC (fAUC0-24/MIC) efficacy, and resistance suppression targets of 40 and 46, respectively, but limited the occurrence of maximum plasma concentrations ≥14 µg/mL.Conclusions: Two gepotidacin 3000 mg oral doses 10-12 hours apart provide ~2-fold higher systemic exposures, increase efficacy for higher gepotidacin MIC N. gonorrhoeae isolates, reduce resistance potential and limit plasma concentrations of potential safety concern, compared with higher doses. [ABSTRACT FROM AUTHOR]

Gepotidacin is a novel, bactericidal, first‐in‐class triazaacenaphthylene antibiotic in late‐phase development for uncomplicated urinary tract infection and uncomplicated urogenital gonorrhea. Two clinical studies were conducted to assess the pharmacokinetics (PK) and interethnic comparisons of oral gepotidacin (free‐base and to‐be‐marketed mesylate formulations) administered as single doses ranging from 1500 to 3000 mg in fed and fasted states, and as 2 × 3000‐mg doses given 12 hours apart under fed conditions in healthy participants of Japanese ancestry. Dose proportionality was observed in plasma exposures, and comparable area under the concentration‐time curve (AUC) and maximum concentration were observed in fed and fasted states. Interethnic comparisons for Japanese versus non‐Japanese participant data showed slightly higher plasma maximum concentration (7%‐30%) yet similar plasma AUCs; slightly lower urine AUCs (11%‐18%) were observed. The slightly higher plasma exposures in healthy Japanese versus White participants in the same study were attributed to lower mean body weights (64 kg versus ≈80 kg). Adverse events were primarily gastrointestinal, and when administered with food, gastrointestinal tolerability was improved. Overall, the gepotidacin PK and safety‐risk profiles in healthy Japanese support potential evaluation of the global clinical doses in future studies. [ABSTRACT FROM AUTHOR]

A 333 bp sequence from a cDNA clone, which was one of three having laccase sequence and was designed in lambda gt-11 using mRNA from an 11 day old mycelium of Agaricus bisporus, was used by researchers to identify more cDNA clones and a genomic clone. The coding sequences discovered were of two similar types but not identical. Other fungal laccases that were cloned, when compared to the deduced amino acid sequences, show that the overall similarities are low, though some sequence is totally conserved at and around the amino acid residues connected with copper binding.

The structure andsynthesis of Agaricus bisporus laccase were described. Purified laccase from both malt-extract and compost cultures showed a predominant band of 65 kDa molecular mass, together with lesser amounts of smaller polypeptides. After treatment with N-glycanase, the polypeptide showed an increase in electrophoretic mobility equivalent to a reduction in molecular mass of about 5kDa, suggesting that the enzyme contained about equal amounts of N- and O-linked carbohydrate. Moreover, the result of C-terminal labelling of laccase showed that the C-terminus of the uncleaved polypeptide may be blocked.