Gepotidacin is a novel, first-in-class triazaacenaphthylene antibiotic that may provide a new treatment option for antibiotic-resistant pathogens. Two pharmacokinetic evaluations of oral gepotidacin are presented; a relative bioavailability study that guided formulation development, followed by an adult and adolescent study of the final formulation. In the relative bioavailability study, after gepotidacin administration to 26 healthy adults as free base roller compacted (RC) tablets, free base high shear wet granulation (HSWG) tablets, and mesylate salt reference capsules, the RC tablet exposure ratios and 90% confidence intervals (CIs) were within the 0.80 to 1.25 confidence bounds; however, the HSWG tablet maximum observed concentration (C max ) was higher compared to the reference (ratio: 1.15; 90% CIs: 1.0113, 1.3047). In the healthy adult (n=16) and adolescent (n=17) study, a gepotidacin mesylate salt tablet was evaluated as a 1,500-mg single dose, 2 doses administered 6 or 12 h apart (6,000 mg total), or placebo. Single-dose mean C max was ∼27% higher in adolescents versus adults and area under the concentration-time curve (AUC) was comparable in both populations. After 2 doses were administered, mean C max was similar for both ages and mean AUC was ∼35% higher in adolescents versus adults. Concentrations increased proportionally with dose. Safety-risk profiles were similar in both ages. Across studies, the most common adverse events were gastrointestinal. Overall, the pharmacokinetics of the final gepotidacin mesylate salt tablet have been well-characterized, enrollment of adolescents into the pivotal trials is supported, and dosing intervals were determined that should provide adequate exposures for microbiological efficacy.

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.

Introduction: Hormonal contraceptives are among the most effective forms of reversible contraception, but many other compounds, including some antiretrovirals, have clinically meaningful drug-drug interactions (DDIs) with hormonal contraceptives. Islatravir is a novel human immunodeficiency virus nucleoside reverse transcriptase translocation inhibitor currently in clinical development for treatment and prevention of HIV infection. A phase 1 clinical trial was conducted to evaluate the DDI of islatravir and the combination of oral contraceptive levonorgestrel (LNG)/ethinyl estradiol (EE). Methods:This was an open-label, two-period, fixed-sequence, DDI clinical trial in healthy, postmenopausal or bilaterally oophorectomized females aged 18 through 65 years in the United States between October 2016 and January 2017. A single dose of LNG 0.15 mg/EE 0.03 mg was given followed by a 7-day washout. Islatravir, 20 mg, was then dosed once weekly for 3 weeks; a single dose of LNG 0.15 mg/EE 0.03 mg was given concomitantly with the third dose of islatravir. Pharmacokinetic samples for plasma LNG and EE concentrations were collected pre-dose and up to 120 hours post-dose in each period. Safety and tolerability were assessed throughout the trial by clinical assessments, laboratory evaluations and examination of adverse events. Results and Discussion: Fourteen participants were enrolled. The pharmacokinetics of LNG and EE were not meaningfully altered by co-administration with islatravir. For the comparison of (islatravir + LNG/EE)/(LNG/EE alone), the geometric mean ratios (GMRs) (90% confidence intervals [CIs]) for LNG AUC 0-inf and C max were 1.13 (1.06, 1.20) and 0.965 (0.881, 1.06), respectively. For EE, the GMRs (90% CI) for AUC 0-inf and C max were 1.05 (0.981, 1.11) and 1.02 (0.971, 1.08), respectively. Co-administration of all three drugs was generally well tolerated. Conclusions: The results of this trial support the use of LNG/EE contraceptives in combination with islatravir without dose adjustment.

BackgroundOver 2 million girls and young women are living with HIV, being newly infected at disproportionately high rates. HIV infection adds risks to pregnancy, including vertical transmission and maternal death. Hormonal contraceptives are among the most effective reversible contraceptives, but they have clinically meaningful drug–drug interactions (DDI) with many antiretrovirals (ARV). MK-8591 is a novel nucleoside reverse transcriptase translocation inhibitor (NRTTI) currently in Phase 2 clinical development for treatment of HIV. Unlike many ARVs, MK-8591 is not an inhibitor or inducer of major CYP enzymes and is not expected to alter the pharmacokinetics (PK) of hormonal contraceptives. This clinical study evaluated the DDI of MK-8591 with levonorgestrel (LNG) and ethinyl estradiol (EE) to support use of hormonal contraceptives with MK-8591.MethodsThis was an open-label, two-period, fixed-sequence DDI study in 14 healthy, postmenopausal or oopherectomized females aged 50–64. A single dose of LNG 0.15 mg/EE 0.03 mg was given followed by a 7-day washout. MK-8591 20 mg was then dosed once weekly for 3 weeks; a single dose of LNG 0.15 mg/EE 0.03 mg was given concomitantly with the third dose of MK-8591. PK samples were collected for evaluation of LNG and EE levels. Individual values of AUC0-inf and Cmax were natural log-transformed prior to analysis and evaluated separately using a linear mixed effects model with a fixed effects term for treatment. An unstructured covariance matrix was used to allow for unequal treatment variances and to model the correlation between the treatment measurements within each subject.ResultsThe PK of EE and LNG were not meaningfully altered by co-administration with MK-8591. For the comparison of (MK-8591 + LNG/EE) / (LNG/EE alone), the geometric mean ratios (GMRs) (90% confidence intervals (CIs)) for LNG AUC0-inf and Cmax were 1.13 (1.06, 1.20) and 0.965 (0.881, 1.06), respectively. For EE the GMRs (90% CI) for AUC0-inf and Cmax were 1.05 (0.981, 1.11) and 1.02 (0.971, 1.08), respectively. Co-administration of all three drugs was generally well tolerated.ConclusionThe results of this study support use of hormonal contraceptives in HIV-infected patients receiving MK-8591.Disclosures W. Ankrom, Merck & Co, Inc.: Employee and Shareholder, Salary. D. Jonathan, Merck: Employee, Salary. D. Rudd, Merck & Co., INC.: Employee, Salary. S. Zhang, Merck & Co, Inc.: Employee, Salary. K. Fillgrove, Merck & Co., Inc.: Employee, Salary. K. Gravesande, Kezia Gravesande: Research Contractor, Salary. R. Matthews, Merck: Employee, Salary. A. Stoch, Merck & Co, Inc.: Employee and Shareholder, Salary. M. Iwamoto, Merck & Co, Inc.: Employee and Shareholder, Salary.

For both comparisons, the 90% CIs of the test/reference ratios were within the regulatory acceptance range (80-125%), suggesting that both test formulations (low Cform and high C-form) were bioequivalent to the reference formulation for Cmax, AUC0-t, and AUC0-∞.