No abstract

Mirabegron is a potent and selective β3-adrenoceptor agonist developed for the treatment of overactive bladder. In vitro studies demonstrated that mirabegron partly acts as a (quasi-) irreversible, metabolism-dependent inhibitor of CYP2D6. The effect of steady-state mirabegron on single doses of the sensitive CYP2D6 substrates metoprolol (100 mg) and desipramine (50 mg) was assessed in two open-label, one-sequence crossover studies in healthy subjects (CYP2D6 extensive metabolizers). Mirabegron 160 mg/day increased metoprolol maximum plasma concentration (C max) 1.90-fold (90 % confidence interval [CI] 1.54; 2.33) and total exposure (AUC0-∞) 3.29-fold (90 % CI 2.70; 4.00) in 12 males (study 1). Mean metoprolol half-life increased from 2.96 to 4.11 h. α-Hydroxymetoprolol C max and AUC to last measurable concentration decreased 2.6-fold and 2.2-fold, respectively. In study 2, mirabegron 100 mg/day increased desipramine C max 1.79-fold (90 % CI 1.69; 1.90) and AUC0-∞ 3.41-fold (90 % CI 3.07; 3.80) in 14 males and 14 females. Mean desipramine half-life increased from 19.5 to 35.8 h. C max of 2-hydroxydesipramine decreased ~twofold, while AUC increased ~1.3-fold. Desipramine was administered again 2 weeks after the last mirabegron dose. Desipramine C max and AUC0-∞ were still ~1.13-fold increased; the 90 % CIs fell within the 0.80-1.25 interval. All treatments were well tolerated. In conclusion, mirabegron is a moderate CYP2D6 inhibitor (ratio and 90 % CI <5.0).

ADX10059 decreased reflux episodes in healthy subjects. The MR formulation is suitable for longer-term treatment to evaluate symptom control in GERD patients.

Mirabegron, a selective β3 -adrenoceptor agonist, is approved for the treatment of overactive bladder (OAB). Solifenacin is a muscarinic receptor antagonist widely used in the treatment of OAB. This open-label, 1-sequence, 2-arm study investigated whether any pharmacokinetic interaction exists between mirabegron and solifenacin. In arm 1, 21 healthy men and women received 10 mg solifenacin succinate alone and in combination with mirabegron 100 mg qd. In arm 2, 20 healthy men and women received 100 mg mirabegron alone and in combination with solifenacin succinate 10 mg qd. Plasma samples were collected and tolerability was assessed. Following coadministration of mirabegron and solifenacin in arm 1, solifenacin geometric mean ratios (90% confidence interval [CI]) for Cmax and AUCinf were 1.23 (1.15, 1.31) and 1.26 (1.17, 1.35), respectively, compared with solifenacin alone, with a 1.07-fold increase in mean t1/2 . In arm 2, mirabegron ratios (90% CI) for Cmax and AUCinf were 0.99 (0.78, 1.26) and 1.15 (1.01, 1.30), respectively, for the combination relative to mirabegron alone, with an increase in mean tmax of approximately 1 hour. Mirabegron or solifenacin alone or in combination was generally well tolerated.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• Darexaban is an oral direct factor Xa inhibitor developed as an antithrombotic for several indications. Several other new oral anticoagulants are metabolized via CYP3A4 and transported by P-glycoprotein, displaying clinically relevant drug interactions with rifampicin and ketoconazole.• Darexaban is almost entirely metabolized to darexaban glucuronide, which is the main active moiety. In vitro, CYP3A4 metabolism is not involved in the formation or metabolism of darexaban glucuronide; and darexaban, but not darexaban glucuronide, is a P-glycoprotein substrate in vitro. WHAT THIS STUDY ADDS• The study shows that rifampicin does not affect the pharmacokinetic profiles of darexaban glucuronide and darexaban to a clinically relevant degree, suggesting that the potential for drug-drug interactions between darexaban and CYP3A4 or P-glycoprotein-inducing agents is low.• This study was carried out to confirm the susceptibility of darexaban/darexaban glucuronide to CYP3A4 and P-glycoprotein induction in vivo in humans. AIMSWe investigated the effects of rifampicin on the pharmacokinetics (PK) of the direct clotting factor Xa inhibitor darexaban (YM150) and its main active metabolite, darexaban glucuronide (YM-222714), which almost entirely determines the antithrombotic effect. METHODSIn this open-label, single-sequence study, 26 healthy men received one dose of darexaban 60 mg on day 1 and oral rifampicin 600 mg once daily on days 4-14. On day 11, a second dose of darexaban 60 mg was given with rifampicin. Blood and urine were collected after study drug administration on days 1-14. The maximal plasma drug concentration (Cmax) and exposure [area under the plasma concentration-time curve from time zero to time of quantifiable measurable concentration; (AUClast) or AUClast extrapolated to infinity (AUC•)] were assessed by analysis of variance of PK. Limits for statistical significance of 90% confidence intervals for AUC and Cmax ratios were predefined as 80-125%. RESULTSDarexaban glucuronide plasma exposure was not affected by rifampicin; the geometric mean ratio (90% confidence interval) of AUClast with/without rifampicin was 1.08 (1.00, 1.16). The Cmax of darexaban glucuronide increased by 54% after rifampicin [ratio 1.54 (1.37, 1.73)]. The plasma concentrations of darexaban were very low (<1% of darexaban glucuronide concentrations) with and without rifampicin. Darexaban alone or in combination with rifampicin was generally safe and well tolerated. CONCLUSIONSOverall, rifampicin did not affect the PK profiles of darexaban glucuronide and darexaban to a clinically relevant degree, suggesting that the potential for drug-drug interactions between darexaban and CYP3A4 or P-glycoprotein-inducing agents is low.