Clinical assessment of gepotidacin (GSK2140944) as a victim and perpetrator of drug-drug interactions via CYP3A metabolism and transporters.

Gepotidacin is a novel triazaacenaphthylene antibiotic in phase III development. Based on nonclinical in vitro characterization of gepotidacin metabolism, two phase I studies were conducted in healthy participants to investigate clinical drug-drug interactions (DDIs). We assessed gepotidacin as a DDI victim with a potent cytochrome P450 (CYP) 3A4/P-glycoprotein (P-gp) inhibitor (itraconazole), potent CYP3A4 inducer (rifampicin), and nonspecific organic cation transporter (OCT)/multidrug and toxic extrusion transporter (MATE) renal transport inhibitor (cimetidine) via single doses of gepotidacin before and after co-administration with multiple doses of the modulator drugs. Gepotidacin DDI perpetrator potential for P-gp inhibition (digoxin) and CYP3A4 inhibition (midazolam) was evaluated via single doses of the two-drug cocktail without and with gepotidacin. The DDI magnitudes were interpreted based on area under the concentration-time curve (AUC). A weak DDI (AUC increase 48%-50%) was observed for gepotidacin co-administered with itraconazole. A clinically significant decrease in gepotidacin plasma AUC (52%) was observed with rifampicin coadministration, indicating a moderate DDI. There was no DDI for gepotidacin with cimetidine; a unique biomarker approach showed increased serum creatinine (24%), decreased renal clearance of creatinine (21%), and N1-methylnicotinamide (39%), which confirmed extensive MATE inhibition and partial OCT2 inhibition. Gepotidacin was not a P-gp DDI perpetrator, although the maximum plasma concentration of digoxin increased (53%) and is potentially clinically relevant given its narrow therapeutic index. Gepotidacin demonstrated weak CYP3A4 inhibition with midazolam (<2-fold AUC increase). There were no new safety-risk profile findings. These results will inform the safe and efficacious clinical use of gepotidacin when co-administered with other drugs.

Selective androgen receptor modulation for muscle weakness in chronic obstructive pulmonary disease: a randomised control trial.

BACKGROUND: Selective androgen receptor modulators (SARMs) increase muscle mass via the androgen receptor. This phase 2A trial investigated the effects of a SARM, GSK2881078, in conjunction with exercise, on leg strength in patients with chronic obstructive pulmonary disease (COPD) and impaired physical function. METHODS: 47 postmenopausal women and 50 men with COPD (forced expiratory volume in 1 s 30%-65% predicted; short physical performance battery score: 3-11) were enrolled into a randomised double-blind, placebo control trial. Patients were randomised 1:1 to once daily placebo or oral GSK2881078 (females: 1.0 mg; males: 2.0 mg) for 13 weeks with a concurrent home-exercise programme, involving strength training and physical activity. Primary endpoints were change from baseline in leg strength at 90 days (one-repetition maximum; absolute (kg) and relative (% change)) and multiple safety outcomes. Secondary endpoints included lean body mass, physical function and patient-reported outcomes. RESULTS: GSK2881078 increased leg strength in men. The difference in adjusted mean change from baseline and adjusted mean percentage change from baseline between treatment and placebo were: for women, 8.0 kg (90% CI -2.5 to 18.4) and 5.2% (90% CI -4.7 to 15.0), respectively; for men, 11.8 kg (90% CI -0.5 to 24.0) and 7.0% (90% CI 0.5 to 13.6), respectively. Lean body mass increased, but no changes in patient-reported outcomes were observed. Reversible reductions in high-density lipoprotein-cholesterol and transient elevations in hepatic transaminases were the main treatment-related safety findings. CONCLUSIONS: GSK2881078 was well tolerated and short-term treatment increased leg strength, when expressed as per cent predicted, in men with COPD more than physical training alone. TRIAL REGISTRATION NUMBER: NCT03359473.

Pharmacokinetic, Safety, and Tolerability Evaluations of Gepotidacin (GSK2140944) in Healthy Japanese Participants.

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.

Therapeutic index of inhaled corticosteroids in asthma: A dose-response comparison on airway hyperresponsiveness and adrenal axis suppression.

AIMS: To compare the airway potency, systemic activity and therapeutic index of three inhaled corticosteroids that differ in glucocorticoid receptor binding affinity, physicochemical and pharmacokinetic properties. METHODS: This escalating-dose, placebo-controlled, cross-over study randomised adults with asthma to 1 or 2 treatment periods with ≥25 days washout in-between. Each treatment period comprised five 7-day dose escalations (µg/d): fluticasone furoate (FF; 25 → 100 → 200 → 400 → 800), fluticasone propionate (FP; 50 → 200 → 500 → 1000 → 2000), budesonide (BUD; 100 → 400 → 800 → 1600 → 3200) or placebo. Airway hyperresponsiveness to adenosine-5'-monophosphate (AMP PC20 ) was assessed on day 8. Plasma cortisol was assessed on day 1 (predose baseline) and from pre-PM dose on day 6 to pre-PM dose day 7 (24-h weighted mean). RESULTS: Fifty-four subjects were randomised. FF showed greater airway potency than FP and BUD (AMP PC20 dose at which 50% of the maximum effect is achieved [ED50 ] values: 48.52, 1081.27 and 1467.36 µg/d, respectively). Systemic activity (cortisol suppression) ED50 values were 899.99, 1986.05 and 1927.42 µg/d, respectively. The therapeutic index (ED50 cortisol suppression/ED50 AMP PC20 ) was wider for FF (18.55) than FP (1.84) and BUD (1.31). FF 100 µg/d and 200 µg/d were both comparable in terms of airway potency with high doses of FP (≥1000 µg twice daily [BID]) and BUD (≥1500 µg/BID). The systemic activity of FF 100 µg/d and 200 µg/d (cortisol suppression: 7.41% and 14.28%, respectively) was comparable with low doses of FP (100 µg/BID and 250 µg/BID) and BUD (100 µg/BID and 200 µg/BID). CONCLUSION: This study provides evidence that FF can provide more protection against airway hyperresponsiveness, with less systemic activity, than FP or BUD. This suggests that all inhaled corticosteroids are not therapeutically similar and may differ in their therapeutic index. (203162; NCT02991859).