Pharmacokinetics and Bioequivalence of Isavuconazole Administered as Isavuconazonium Sulfate Intravenous Solution via Nasogastric Tube or Orally in Healthy Subjects.

For critically ill patients with invasive fungal infections, a nasogastric (NG) tube can be an alternative route for administration of isavuconazonium sulfate (ISAVUSULF). This was a randomized, open-label, 2-period, 2-sequence single-dose crossover study comparing single doses of 372 mg ISAVUSULF intravenous (i.v.) solution via NG tube (test formulation) to 372-mg ISAVUSULF capsules for oral administration (reference formulation) in healthy male and female subjects. A single dose of ISAVUSULF was administered under fasting conditions on day 1 of each period, with a washout of 30 days between periods. Pharmacokinetic (PK) samples were collected predose through day 21. Standard safety and tolerability assessments were conducted in each period. The analysis of variance estimate of the study population demonstrates that the isavuconazole i.v. NG tube administration geometric least-squares (LS) mean values of the observed maximum concentration (Cmax), area under the plasma concentration-time curve (AUC) to the last measurable concentration (AUClast), AUC to time infinity (AUCinf), and AUC from start of dosing to 72 h (AUC72) were 105.3%, 97.6%, 99.3%, and 97.8%, respectively, of the corresponding oral-administration values. The geometric LS mean ratio and 90% confidence intervals for the PK parameters were completely contained within the prespecified limits of 80% to 125%. There were no deaths or serious adverse events that led to the withdrawal of treatment during the study. The study met its primary endpoint of bioequivalence between the two routes of administration. Both routes of administration were well tolerated.

Single dose pharmacokinetics and absolute bioavailability of mirabegron, a ß3-adrenoceptor agonist for treatment of overactive bladder.

BACKGROUND AND OBJECTIVES: Mirabegron is a potent and selective ß3-adrenoceptor agonist in development for treatment of overactive bladder. METHODS: Mirabegron pharmacokinetics after single intravenous (i.v.) and oral doses, absolute bioavailability (F), dose proportionality, sex differences and tolerability were assessed in 2 single-dose, open-label, randomized, parallel-group, cross-over studies in healthy men (exploratory Study 1, n = 12) and men and women (Study 2, n = 91). RESULTS: After oral dosing (25 - 150 mg), peak plasma concentrations were attained after ~ 4 h. Mean half-life was around 40 h for both routes of administration. Volume of distribution at steady state was 1,670 l and total clearance was around 57 l/h for i.v. dosing. Mirabegron pharmacokinetics were linear after i.v. dosing (7.5 - 50 mg), but exposure increased more than proportionally after oral dosing due to increased F (29% for 25 mg to 45% at 150 mg). About 20% of the (absorbed) dose was excreted unchanged into urine. Area under the curve (AUC) was 27% and 64% higher in females than males after i.v. and oral dosing respectively; differences were mostly attributed to body weight, and for oral dosing, also to F. CONCLUSIONS: Mirabegron pharmacokinetics were linear after i.v. dosing (7.5 - 50 mg), but increased more than proportionally after oral dosing (25 - 150 mg) as a result of increased F. Sex differences in exposure could be explained by body weight and for oral dosing, also by F. Mirabegron was in general well tolerated up to the highest doses studied, 50 mg i.v. and 150 mg oral.

Effect of enzalutamide on PK of P-gp and BCRP substrates in cancer patients: CYP450 induction may not always predict overall effect on transporters.

Drug-drug interaction (DDI) is an important consideration for clinical decision making in prostate cancer treatment. The objective of this study was to evaluate the effect of enzalutamide, an oral androgen receptor inhibitor, on the pharmacokinetics (PK) of digoxin (P-glycoprotein [P-gp] probe substrate) and rosuvastatin (breast cancer resistance protein [BCRP] probe substrate) in men with metastatic castration-resistant prostate cancer (mCRPC). This was a phase I, open-label, fixed-sequence, crossover study (NCT04094519). Eligible men with mCRPC received a single dose of transporter probe cocktail containing 0.25 mg digoxin and 10 mg rosuvastatin plus enzalutamide placebo-to-match on day 1. On day 8, patients started 160 mg enzalutamide once daily through day 71. On day 64, patients also received a single dose of the cocktail. The primary end points were digoxin and rosuvastatin plasma maximum concentration (Cmax ), area under the concentration-time curve from the time of dosing to the last measurable concentration (AUClast ), and AUC from the time of dosing extrapolated to time infinity (AUCinf ). Secondary end points were enzalutamide and N-desmethyl enzalutamide (metabolite) plasma Cmax , AUC during a dosing interval, where tau is the length of the dosing interval (AUCtau ), and concentration immediately prior to dosing at multiple dosing (Ctrough ). When administered with enzalutamide, there was a 17% increase in Cmax , 29% increase in AUClast , and 33% increase in AUCinf of plasma digoxin compared to digoxin alone, indicating that enzalutamide is a "mild" inhibitor of P-gp. No PK interaction was observed between enzalutamide and rosuvastatin (BCRP probe substrate). The PK of enzalutamide and N-desmethyl enzalutamide were in agreement with previously reported data. The potential for transporter-mediated DDI between enzalutamide and digoxin and rosuvastatin is low in men with prostate cancer. Therefore, concomitant administration of enzalutamide with medications that are substrates for P-gp and BCRP does not require dose adjustment in this patient population.

Time-dependent inhibitory effects of (1R,9S,12S,13R,14S,17R,18E,21S,23S,24R,25S,27R)-1,14-dihydroxy-12-(E)-2-[(1R,3R,4R)-4-hydroxy-3-methoxycyclohexyl]-1-methylvinyl-23,25-dimethoxy-13,19,21,27-tetramethyl-17-(2-oxopropyl)-11,28-dioxa-4-azatricyclo[22.3.1.0(4.9)]octacos-18-ene-2,3,10,16-tetrone (FK1706), a novel nonimmunosuppressive immunophilin ligand, on CYP3A4/5 activity in humans in vivo and in vitro.

We investigated the inhibitory effects of (1R,9S,12S,13R,14S,17R,18E,21S,23S,24R,25S,27R)-1, 14-dihydroxy-12-(E)-2-[(1R,3R,4R)-4-hydroxy-3-methoxycyclohexyl]-1-methylvinyl-23,25-dimethoxy-13,19,21,27-tetramethyl-17-(2-oxopropyl)-11,28-dioxa-4-azatricyclo [22.3.1.0(4.9)]octacos-18-ene-2,3,10,16-tetrone (FK1706), a novel nonimmunosuppressive immunophilin ligand, on CYP3A4/5 in in vitro and in vivo settings. First, the inhibitory effects of FK1706 (preincubation dependence, inactivation rate estimation, and reversibility) were tested using human liver microsomes. Second, the effect of repeated oral doses of FK1706 (60 mg q.d. for 14 days) on the pharmacokinetics of midazolam (single oral 2-mg dose) was tested in healthy volunteers. Finally, pharmacokinetic modeling and simulation were performed. In vitro experiments showed that FK1706 inhibited CYP3A4/5 in a time-dependent and irreversible manner. The in vitro maximum inactivation rate constant (k(inact)) and concentration of inhibitor that gave half-maximal k(inact) (K(I)) were estimated to be 10.1 h(-1) and 2050 ng/ml, respectively. In the clinical study, FK1706 produced a 2-fold increase in the area under the time-concentration curve (AUC) of midazolam. A pharmacokinetic model developed for this study, which described the time course of concentrations of both FK1706 and midazolam and incorporated CYP3A4/5 inactivation in the liver and intestine, successfully predicted the change in the pharmacokinetics of midazolam using in vitro k(inact) and K(I) values (1.66- to 2.81-fold increases in AUC predicted) and estimated the in vivo inactivation rate to be 0.00404 to 0.0318 h(-1) x ml/ng. In conclusion, FK1706 weakly or moderately inhibited the activity of CYP3A4/5 in vitro and vivo at the tested dose. The model developed here would be helpful in predicting drug-drug interactions and in the design of dose regimens that avoid drug-drug interactions.

Investigation of Potential Drug-Drug Interactions between Peficitinib (ASP015K) and Methotrexate in Patients with Rheumatoid Arthritis.

BACKGROUND: Methotrexate is frequently used to treat rheumatoid arthritis. Peficitinib (ASP015K; Smyraf®), an oral Janus kinase inhibitor indicated for the treatment of rheumatoid arthritis, may be coadministered with methotrexate. OBJECTIVE: The objective of this study was to investigate potential drug-drug interactions of peficitinib with methotrexate and the short-term safety of coadministration. PATIENTS AND METHODS: This phase I, open-label, single-sequence study included patients with rheumatoid arthritis taking a stable dose of methotrexate. Patients received their prescribed methotrexate dose (Day 1) and then peficitinib (100 mg) twice daily from Day 3 until the morning of Day 9; a second methotrexate dose was coadministered with peficitinib on Day 8. Serial blood samples were collected for methotrexate concentration after dosing on Days 1 (methotrexate alone) and 8 (methotrexate plus peficitinib) and for peficitinib concentration after dosing on Days 7 (peficitinib alone) and 8 (methotrexate plus peficitinib). Pre-dose concentrations of peficitinib were measured (Days 3-8). RESULTS: Peficitinib concentrations reached steady state on Day 5. Administration of peficitinib did not result in changes to methotrexate area under the concentration-time curve from time zero to infinity or maximum observed concentration following a methotrexate dose (15-25 mg), and there was no significant effect of methotrexate (15-25 mg) on peficitinib area under the concentration-time curve within a 12-hour dosing interval. There were no new tolerability or safety signals after coadministration of peficitinib and methotrexate. One patient experienced two serious adverse events and withdrew from the study without receiving peficitinib. CONCLUSIONS: Pharmacokinetic results showed no significant interactions between peficitinib and methotrexate. CLINICALTRIALS. GOV IDENTIFIER: NCT01754805.

Pharmacokinetic Profile of Gilteritinib: A Novel FLT-3 Tyrosine Kinase Inhibitor.

BACKGROUND AND OBJECTIVE: Gilteritinib is a novel, highly selective tyrosine kinase inhibitor approved in the USA, Canada, Europe, Brazil, Korea, and Japan for the treatment of FLT3 mutation-positive acute myeloid leukemia. This article describes the clinical pharmacokinetic profile of gilteritinib. METHODS: The pharmacokinetic profile of gilteritinib was assessed from five clinical studies. RESULTS: Dose-proportional pharmacokinetics was observed following once-daily gilteritinib administration (dose range 20-450 mg). Median maximum concentration was reached 2-6 h following single and repeat dosing of gilteritinib; mean elimination half-life was 113 h. Elimination was primarily via feces. Exposure to gilteritinib was comparable under fasted and fed conditions. Gilteritinib is primarily metabolized via cytochrome P450 (CYP) 3A4; coadministration of gilteritinib with itraconazole (a strong P-glycoprotein inhibitor and CYP3A4 inhibitor) or rifampicin (a strong P-glycoprotein inducer and CYP3A inducer) significantly affected the gilteritinib pharmacokinetic profile. No clinically relevant interactions were observed when gilteritinib was coadministered with midazolam (a CYP3A4 substrate) or cephalexin (a multidrug and toxin extrusion 1 substrate). Unbound gilteritinib exposure was similar between subjects with hepatic impairment and normal hepatic function. CONCLUSIONS: Gilteritinib exhibits a dose-proportional pharmacokinetic profile in healthy subjects and in patients with relapsed/refractory acute myeloid leukemia. Gilteritinib exposure is not significantly affected by food. Moderate-to-strong CYP3A inhibitors demonstrated a significant effect on gilteritinib exposure. Coadministration of gilteritinib with CYP3A4 or multidrug and toxin extrusion 1 substrates did not impact substrate concentrations. Unbound gilteritinib was comparable between subjects with hepatic impairment and normal hepatic function; dose adjustment is not warranted for patients with hepatic impairment. CLINICAL TRIAL REGISTRATION: NCT02014558, NCT02456883, NCT02571816.

Pharmacokinetic drug interaction study between overactive bladder drugs mirabegron and tolterodine in Japanese healthy postmenopausal females.

Mirabegron, the first selective ß3-adrenoceptor agonist for the treatment of overactive bladder (OAB), inhibits cytochrome P450 isozyme CYP2D6. This study was performed in Japanese healthy postmenopausal female volunteers to assess any pharmacokinetic drug interaction between mirabegron and tolterodine, another OAB drug and a sensitive substrate of CYP2D6. Tolterodine 4 mg was orally administered from Days 1-7 and co-administered with mirabegron 50 mg from Days 8-14. Mirabegron 50 mg increased maximum concentration (Cmax) and area under the concentration-time curve from zero to 24 h after dosing (AUC24h) of tolterodine by 2.06-fold (90% confidence interval [CI] 1.81, 2.34) and 1.86-fold (90% CI 1.60, 2.16), respectively, and increased Cmax and AUC24h of the metabolite 5-hydroxymethyl tolterodine by 1.36-fold (90% CI 1.26, 1.47) and 1.25-fold (90% CI 1.15, 1.37), respectively. This suggested a weak pharmacokinetic drug interaction between mirabegron and tolterodine. Mean change from baseline of Fridericia's QT correction formula (ΔQTcF) was slightly higher on Day 14 than on Day 7. No subject had QTcF >480 msec or ΔQTcF >60 msec. All the treatment-emergent adverse events were mild. Mirabegron 50 mg was considered to be safe and well tolerated when coadministered with tolterodine 4 mg in healthy postmenopausal female volunteers.

Effects of food intake on the pharmacokinetic properties of mirabegron oral controlled-absorption system: a single-dose, randomized, crossover study in healthy adults.

BACKGROUND: Mirabegron is a ß3-adrenoceptor agonist used for the treatment of overactive bladder. Mirabegron is formulated as an extended-release tablet using oral controlled-absorption system (OCAS) technology. OBJECTIVE: This study was designed to assess the effects of food on the pharmacokinetic properties of mirabegron OCAS in accordance with regulatory requirements to support dosing recommendations. METHODS: In this single-dose, randomized, open-label, 3-period, parallel-dose-group, crossover study, mirabegron OCAS 50 or 100 mg was administered orally to healthy adult subjects in the fasted state or after a high- or low-fat breakfast. Dose administrations were separated by a washout period of at least 10 days. Blood samples were drawn up to 96 hours after dosing, and plasma concentrations of mirabegron were analyzed by LC/MS-MS. PK properties were determined using noncompartmental methods. Primary end points for the assessment of food effects were Cmax and AUC0-∞. For tolerability assessment, adverse events (AEs) were monitored using investigators' questionnaires and subjects' spontaneous reports, vital sign measurements, hematology, clinical chemistry, and ECG. RESULTS: Thirty-eight subjects (male, 50%; mean age, 32.1 years; mean weight, 77.3 kg; race, 76.3% white) were enrolled in the 50-mg dose group and 38 subjects (male, 52.6%; mean age, 30.9 years; mean weight, 74.5 kg; race, 63.2% white) in the 100-mg dose group. With either fed condition or dose, the 90% CIs for the fed/fasted ratios of both Cmax and AUC0-∞ of mirabegron fell below the predetermined range for bioequivalence (80.0%-125.0%), suggesting that food had no effect on exposure to mirabegron OCAS. With the 50-mg dose, mirabegron Cmax was reduced by 45% with a high-fat breakfast compared with fasted conditions (geometric mean ratio [GMR], 54.8% [90% CI, 43.7%-68.6%]) and AUC0-∞, by 17% (GMR, 83.2% [90% CI, 74.2%-93.4%]). With the 100-mg dose, mirabegron Cmax and AUC0-∞ were reduced by 39% (GMR, 61.3% [90% CI, 47.8%-78.7%]) and 18% (82.4% [72.6%-93.5%]), respectively, after a high-fat breakfast. With the 50-mg dose, mirabegron Cmax was decreased by 75% (GMR, 25.0% [90% CI, 19.9%-31.3%]) and AUC0-∞ by 51% (48.7% [43.3%-54.7%]) after a low-fat breakfast. Corresponding reductions with the 100-mg dose were 64% (GMR, 36.3% [90% CI, 28.2%-46.8%]) for Cmax and 47% (GMR, 53.2% [90% CI, 46.8%-60.5%]) for AUC0-∞. The fed/fasted ratios for mirabegron Cmax and AUC0-∞ were in general independent of dose or sex. Food delayed Tmax compared with the fasted state, with similar increases with the high- and low-fat meals (0.9 hours with 50 mg and 1.5-2.0 hours with 100 mg). Mirabegron was generally well tolerated, with no apparent difference in AE frequency between the fasted and fed states. CONCLUSIONS: Mirabegron OCAS tablets exhibited a decrease in mirabegron plasma exposure with food that was independent of dose (50 or 100 mg) or gender but dependent on meal composition. A greater reduction in mirabegron exposure was observed after a low-fat breakfast compared with after a high-fat breakfast. Based on findings from previous studies, the effects of food observed in this study do not warrant dose adjustment in clinical practice. ClinicalTrials.gov identifier: NCT00939757.

Role of cytochrome p450 isoenzymes 3A and 2D6 in the in vivo metabolism of mirabegron, a ß3-adrenoceptor agonist.

BACKGROUND: Mirabegron is a ß3-adrenoceptor agonist for the treatment of overactive bladder. There has been little information published or presented about the involvement of cytochrome P450 (CYP) isoenzymes 3A and 2D6 in the metabolism of mirabegron in humans; in vitro data indicate that oxidative metabolism is primarily mediated by CYP3A with a minor role for CYP2D6. OBJECTIVE: To determine to what extent CYP3A and CYP2D6 isoenzymes are involved in mirabegron metabolism. METHODS: Two open-label, randomized, one-sequence crossover drug-drug interaction studies in healthy subjects were conducted to assess the effect of ketoconazole and rifampicin on the pharmacokinetics of mirabegron and two parallel-group studies in healthy subjects with either known confirmed or predicted CYP2D6 phenotype. RESULTS: Co-administration of multiple dosages of 400 mg/day ketoconazole with a single 100 mg mirabegron oral controlled absorption system (OCAS) dose increased mirabegron maximum concentration (C(max)) and area under the curve extrapolated to infinity (AUC∞) to 145 % (90 % confidence interval [CI] 123-172 %] and 181 % (90 % CI 163-201 %), respectively. Co-administration of multiple dosages of 600 mg/day rifampicin with a single 100 mg mirabegron OCAS dose decreased mirabegron C max and AUC∞ to 65 % (90 % CI 50-86 %) and 56 % (90 % CI 49-65 %), respectively, without an effect on terminal elimination half-life (t(½)). The urinary excretion of mirabegron was increased by ketoconazole and decreased by rifampicin, reflecting the AUC changes, whereas renal clearance was not affected. Ketoconazole decreased mirabegron t ½ from 50.9 to 37.6 h suggesting that volume of distribution as well as first-pass effect decreased. Rifampicin did not affect mirabegron t ½, suggesting that it affects first pass through the intestinal wall or liver. Rifampicin greatly increased the ratio to parent drug of the presumed CYP-mediated mirabegron metabolites M8 and M15 by 777 and 646 %. Steady-state mirabegron pharmacokinetic parameters (50 and 100 mg mirabegron OCAS) were similar in 13 CYP2D6 poor, 40 intermediate, and 99 extensive metabolizers, whereas C max and AUC under the dosing interval τ of 24 h (AUCτ) were 30-47 % lower in 10 ultrarapid metabolizers. After administration of 160 mg mirabegron immediate release, C(max) was 14 % and AUC∞ 19 % higher in eight poor metabolizers than in eight extensive metabolizers (phenotyped) with similar t ½. All treatments were well tolerated. CONCLUSIONS: Mirabegron is metabolized by CYP3A and to a minor extent by CYP2D6 in humans. Mirabegron is not considered a sensitive substrate of CYP3A in vivo, as ketoconazole increased mirabegron exposure by less than 2-fold. The effect of CYP2D6 phenotype on mirabegron exposure is small and likely of limited clinical importance.

Effect of renal or hepatic impairment on the pharmacokinetics of mirabegron.

BACKGROUND AND OBJECTIVES: Mirabegron, a selective ß3-adrenoceptor agonist for the treatment of overactive bladder (OAB), is eliminated by renal and metabolic routes. The potential influence of renal or hepatic impairment on the pharmacokinetics of mirabegron was evaluated. METHODS: Two separate open-label, single-dose, parallel-group studies were conducted. Male and female subjects (n = 8 per group) were categorized according to their baseline renal function (mild, moderate, severe or no impairment as determined by estimated glomerular filtration rate [eGFR] using the abbreviated modification of diet in renal disease formula) or hepatic function (mild, moderate or no impairment as determined by the Child-Pugh classification). All subjects received a single oral 100 mg dose of mirabegron. Non-compartmental pharmacokinetic parameters were determined from plasma and urine concentration-time data of mirabegron and metabolites. RESULTS: Compared with healthy subjects who were similar overall in terms of age, sex and body mass index (BMI), the geometric mean area under the plasma concentration-time curve from time zero extrapolated to infinity (AUC(∞)) for mirabegron was 31, 66 and 118 % higher in subjects with mild, moderate and severe renal impairment, respectively. Peak plasma concentrations (C(max)) increased 6, 23 and 92 %, respectively, in subjects with mild, moderate and severe renal impairment. Renal clearance but not apparent total body clearance of mirabegron correlated well with renal function. Compared with healthy subjects matched for age, sex and BMI, mirabegron AUC(∞) values were 19 and 65 % higher in subjects with mild and moderate hepatic impairment, respectively. Mirabegron C(max) was 9 and 175 % higher, respectively, compared with matched healthy subjects. No clear relationship was evident between pharmacokinetic parameters and Child-Pugh scores. Protein binding was approximately 71 % in healthy subjects and was not altered to a clinically significant extent in subjects with renal or hepatic impairment. No consistent changes in mirabegron elimination half-life were observed in subjects with renal or hepatic impairment. There was high pharmacokinetic variability and significant overlap in exposures between subjects with renal or hepatic impairment and healthy subjects. CONCLUSION: Mirabegron AUC(∞) and C(max) increased 118 and 92 %, respectively, in subjects with severe renal impairment, and 65 and 175 %, respectively, in subjects with moderate hepatic impairment. Pharmacokinetic changes observed in subjects with mild or moderate renal impairment or mild hepatic impairment are of small magnitude and likely to be without clinical importance.