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Objective: The potential for drug-drug interaction of multiple-dose intranasal zavegepant on the single-dose oral contraceptive ethinyl estradiol and levonorgestrel (EE-LNG) was evaluated., Background: Zavegepant (as a nasal spray) is a calcitonin gene-related peptide receptor antagonist approved in the United States for treatment of acute migraine in adults., Methods: This single-center, Phase 1, open-label, fixed-sequence study included healthy, nonsmoking females (18-45 years old). In treatment Period 1, a single oral dose of EE-LNG 0.02-0.10 mg was administered on Day 1. In treatment Period 2, intranasal zavegepant (20 mg daily; 10 mg per nostril separated by 1 h) was administered on Days 1-5; 1 oral dose of EE-LNG 0.02-0.10 mg was administered immediately after first 10 mg intranasal zavegepant dose on Day 2. Blood samples for EE-LNG concentrations were collected on Day 1, treatment Period 1, and Day 2, treatment Period 2, and zavegepant concentrations on Day 2, treatment Period 2. Noncompartmental pharmacokinetic parameters included maximum observed concentration (C max ), area under the concentration-time curve (AUC) from Time 0 to last non-zero concentration (AUC 0-t ), and AUC from Time 0 to infinity (AUC 0-inf ). The safety and pharmacokinetic sample sizes were 26 and 23, respectively., Results: Statistical comparisons of pharmacokinetic exposure parameters after co-administration of zavegepant and EE-LNG versus EE-LNG alone showed small, but statistically insignificant, changes in either EE or LNG exposure. EE comparison ratios (90% confidence intervals [CIs]) were 109.9% (105.3%, 114.8%) for AUC 0-inf and 110.2% (104.6%, 116.1%) for C max . LNG comparison ratios (90% CIs) were 107.0% (100.2%, 114.3%) for AUC 0-inf and 108.8% (99.9%, 118.4%) for C max . Frequently reported treatment-emergent adverse events included dysgeusia (n = 25, 96%), throat irritation (n = 11, 42%), headache (n = 10, 39%), nasal discomfort (n = 7, 27%), pharyngeal paresthesia (n = 5, 19%), and nausea (n = 4, 15%)., Conclusion: Co-administration of zavegepant nasal spray with a single dose of an oral contraceptive resulted in no clinically meaningful changes (<12% increase) in EE-LNG exposure., (© 2024 Pfizer Inc. and The Author(s). Headache: The Journal of Head and Face Pain published by Wiley Periodicals LLC on behalf of American Headache Society.)

Objective: To evaluate the pharmacodynamic (PD) and pharmacokinetic (PK) interactions between zavegepant and sumatriptan in healthy adults., Background: Zavegepant is a high-affinity, selective, small-molecule calcitonin gene-related peptide receptor antagonist administered as a nasal spray approved in the United States for the acute treatment of migraine. Triptans, including sumatriptan, are a different class of drugs for acute migraine treatment and are associated with a risk of increased blood pressure (BP). Hence, it is important to study the drug-drug interactions between zavegepant and sumatriptan due to potential coadministration in clinical settings., Methods: This was a Phase 1, single-center, partially blind, randomized, placebo-controlled, single-arm study. Eligible participants were males aged ≥ 18 and ≤ 40 years or females aged ≥ 18 and ≤ 50 years. On Day 1, participants received sumatriptan 2 × 6 mg subcutaneous injections (1 h apart) and were then randomized (6:1 ratio) to receive zavegepant 2 × 10 mg nasal spray (1 in each nostril) or placebo on Days 2 and 3. On Day 4, zavegepant or placebo was coadministered with sumatriptan after the second sumatriptan injection. BP, PK, and safety were evaluated at pre-specified time points., Results: Forty-two participants enrolled in the study received at least one dose of any treatment and were included in the safety analyses. Forty-one participants who completed the study were included in the BP and PK analyses. The mean (standard deviation) time-weighted average (TWA) of mean arterial pressure (MAP [sumatriptan + zavegepant 87.2 (6.8) vs. sumatriptan 86.9 (6.0)]), diastolic BP (DBP [sumatriptan + zavegepant 72.3 (6.8) vs. sumatriptan 72.1 (6.2)]), and systolic BP (SBP [sumatriptan + zavegepant 116.8 (10.2) vs. sumatriptan 116.2 (8.6)]) did not change following zavegepant and sumatriptan coadministration on Day 4 compared to sumatriptan alone on Day 1. Statistical comparisons of the TWA of MAP, DBP, and SBP between sumatriptan and zavegepant coadministration and sumatriptan alone were similar; the differences observed were 0.04 mmHg for MAP (90% confidence interval [CI]: -0.69, 0.77 mmHg), 0.00 mmHg for DBP (90% CI: -0.76, 0.76 mmHg), and 0.33 mmHg for SBP (90% CI: -0.97, 1.63 mmHg). Sumatriptan PK after sumatriptan and zavegepant coadministration versus sumatriptan alone was similar; the comparison ratios were 102.5% (90% CI: 100.7%, 104.2%) for AUC 0-inf and 104.1% (90% CI: 98.0%, 110.6%) for C max . A small difference in zavegepant PK exposure after sumatriptan and zavegepant coadministration versus zavegepant alone was not considered clinically relevant: the comparison ratios were 112.4% (90% CI: 103.4%, 122.3%) for AUC 0-24 and 96.7% (90% CI: 88.9%, 105.2%) for C max . Overall, 90% (38/42) of participants experienced ≥ 1 treatment-emergent adverse event that was mild or moderate in severity. All treatments were generally safe and well tolerated., Conclusion: Coadministration of zavegepant with sumatriptan was safe and without PD or PK interactions in healthy adults., (© 2024 Pfizer Inc and The Author(s). Headache: The Journal of Head and Face Pain published by Wiley Periodicals LLC on behalf of American Headache Society.)

Rimegepant is a calcitonin gene-related peptide receptor antagonist approved for migraine treatment. This phase 1, open-label, single-center, fixed-sequence study evaluated the effect of rimegepant on the pharmacokinetics (PK) of metformin. Twenty-eight healthy participants received metformin 500 mg twice daily from Days 1 to 4 and Days 7 to 10, and once daily on Days 5 and 11. Rimegepant, 75 mg tablet, was administered once daily from Days 9 to 12. At pre-specified time points, plasma metformin concentration, serum glucose levels, and safety and tolerability were evaluated. A 16% increase in the area under the plasma metformin concentration-time curve (AUC) for 1 dosing interval (AUC 0-τ,ss ), a statistically insignificant increase in maximum and minimum steady-state metformin concentration (C max,ss and C min,ss ), and a decrease in metformin renal clearance were observed on Day 11 following metformin-rimegepant coadministration compared with metformin alone; however, the changes were not clinically relevant. Additionally, coadministration of rimegepant with metformin did not induce clinically meaningful change in the maximum observed glucose concentration (G max ) or AUC gluc compared with metformin alone. Overall, rimegepant and metformin coadministration did not result in clinically relevant changes in metformin PK, renal clearance, or the antihyperglycemic effects of metformin. Rimegepant is considered safe for use with metformin., (© 2024 Pfizer Inc and The Authors. Clinical Pharmacology in Drug Development published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Crizotinib is a small-molecule, multitargeted tyrosine kinase inhibitor that exhibits decreased aqueous solubility at a higher pH. This open-label, randomized, phase 1 study (NCT01549574) evaluated the effect of multiple doses of the proton pump inhibitor esomeprazole on the pharmacokinetics (PK) of crizotinib and the safety of crizotinib with or without esomeprazole in healthy adults. Participants received a single 250-mg crizotinib dose after overnight fast or a single 250-mg crizotinib dose following esomeprazole 40 mg/day for 5 days. After a washout of ≥14 days, participants crossed over to the alternate treatment. Blood samples for plasma analysis were taken up to 144 hours after crizotinib dosing and relevant PK parameters estimated. Safety was assessed in all participants receiving ≥1 dose of study medication. Fifteen participants were evaluable for PK and safety for each treatment. Coadministration with esomeprazole resulted in a slight decrease (≈10%) in the crizotinib geometric mean area under the plasma concentration-time profile from time 0 to infinity (adjusted geometric mean ratio, 89.81% [90% confidence interval, 79.05-102.03]). Coadministration of esomeprazole did not affect peak crizotinib exposure. Adverse events (AEs) occurred in similar numbers between treatments; no serious or severe AEs occurred. The most common AE was diarrhea. Although esomeprazole decreased total exposure of crizotinib, it is not considered clinically meaningful, and dose modification is not required when crizotinib is coadministered with agents that affect gastric pH., (© 2021 Pfizer Inc. Clinical Pharmacology in Drug Development published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

A fixed-dose combination (FDC) product of a selective sodium-glucose cotransporter 2 inhibitor ertugliflozin and immediate-release metformin is approved for type 2 diabetes mellitus in the United States, European Union countries, Canada, and other countries. Two studies were conducted to assess the bioequivalence of metformin in the ertugliflozin/metformin FDC tablets to the corresponding doses of Canadian-sourced metformin (Glucophage) coadministered with ertugliflozin. Both studies were phase 1 randomized, open-label, 2-period, single-dose crossover studies (n = 32) in which healthy subjects received an ertugliflozin/metformin FDC tablet (2.5/500 mg or 7.5/850 mg) and the respective doses of the individual components (ertugliflozin coadministered with Canadian-sourced metformin) under fasted (n = 18) or fed (n = 14) conditions. Blood samples were collected 72 hours postdose to determine metformin concentrations. The 90% confidence intervals were within the bioequivalence acceptance criteria for the adjusted geometric mean ratios (FDC:coadministered) for metformin area under the plasma concentration-time curve from time zero to time t, where t is the last point with a measurable concentration and peak observed plasma concentration for both dose strengths under fasted and fed conditions. All study medications were well tolerated. Bioequivalence was demonstrated for the metformin component of the ertugliflozin/metformin FDC tablets and the corresponding doses of the Canadian-sourced metformin coadministered with ertugliflozin., (© 2020 Pfizer Inc. Meck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc. Clinical Pharmacology in Drug Development published by Wiley Periodicals LLC on behalf of American College of Clinical Pharmacology.)

Ertugliflozin, a sodium-glucose cotransporter 2 inhibitor for the treatment of type 2 diabetes mellitus, prevents renal glucose reabsorption resulting in urinary glucose excretion. This open-label, parallel cohort, randomized study conducted in healthy Chinese adults residing in China assessed the pharmacokinetics, tolerability, and safety of 5 mg and 15 mg of ertugliflozin following single (fasted condition) and multiple-dose (fed condition) administration. Sixteen subjects were randomized and completed the study. Ertugliflozin absorption was rapid, with maximum plasma concentrations observed 1 hour after dosing under fasted conditions and 2 to 4 hours after dosing under fed conditions. Following single- and multiple-dose administration, ertugliflozin exhibited dose-proportional exposures with an apparent mean terminal half-life of approximately 9.5 to 11.9 hours. Steady state was reached after 4 once-daily doses. The accumulation ratio based on the area under the plasma concentration-time curve after multiple-dose administration was approximately 1.3 and 1.2 for ertugliflozin 5 mg and 15 mg, respectively. Ertugliflozin was generally well tolerated following administration of single and multiple oral doses of 5 mg and 15 mg in healthy Chinese subjects. Pharmacokinetic comparison with non-Asian subjects indicated that there are no clinically meaningful racial differences and no dose modification of ertugliflozin is required based on race or body weight., (© 2019 The Authors. Clinical Pharmacology in Drug Development published by Wiley Periodicals, Inc. on behalf of American College of Clinical Pharmacology.)

A fixed-dose combination (FDC) tablet of ertugliflozin, a selective inhibitor of sodium-glucose cotransporter 2, and sitagliptin, a dipeptidyl peptidase-4 inhibitor, was developed for the treatment of patients with type 2 diabetes mellitus. Four studies were conducted under fasted conditions to demonstrate bioequivalence of ertugliflozin/sitagliptin FDC tablets and individual components at respective strengths when coadministered in healthy subjects. All studies had open-label, randomized, 2-period, 2-sequence, single-dose crossover designs. In each study 18 or 19 subjects were enrolled and received an ertugliflozin/sitagliptin FDC tablet (5 mg/50 mg, 5 mg/100 mg, 15 mg/50 mg, or 15 mg/100 mg) and corresponding strengths of ertugliflozin and sitagliptin coadministered as individual components. For both ertugliflozin and sitagliptin, the 90%CIs for the ratio (FDC:coadministration) of geometric means for area under the plasma concentration-time profile from time 0 extrapolated to infinite time, and maximum observed plasma concentration, were within acceptance criteria for bioequivalence (80% to 125%). All adverse events were mild in intensity. The 4 studies demonstrated that each strength of FDC tablet is bioequivalent to the respective dose of coadministered individual components. This indicates that the known efficacy and tolerability of ertugliflozin and sitagliptin when coadministered can be translated to the use of a FDC formulation., (© 2019 Pfizer Inc. Clinical Pharmacology in Drug Development published by Wiley Periodicals, Inc. on behalf of The American College of Clinical Pharmacology.)

Ertugliflozin, an inhibitor of sodium-glucose cotransporter 2, is approved in the United States and European Union for the treatment of type 2 diabetes in adults, both as monotherapy and as part of fixed-dose combination (FDC) therapies with either sitagliptin or immediate-release metformin. The effect of a standard, high-fat breakfast on the pharmacokinetics of the highest strengths of ertugliflozin monotherapy (15 mg), ertugliflozin/sitagliptin FDC (15-/100-mg), and ertugliflozin/metformin FDC (7.5-/1000-mg) tablets was evaluated. In 3 separate open-label, 2-period, 2-sequence, single-dose, crossover studies, 14 healthy subjects per study were randomized to receive either ertugliflozin monotherapy or FDC tablets comprising ertugliflozin and sitagliptin or ertugliflozin and metformin under fasted and fed (or vice versa) conditions. Food did not meaningfully affect the pharmacokinetics of ertugliflozin, sitagliptin, or metformin. For FDCs, the effect of food was consistent with that described for individual components. All treatments were well tolerated. Ertugliflozin and ertugliflozin/sitagliptin FDC tablets can be administered without regard to meals. As metformin is administered with meals because of its gastrointestinal side effects, the ertugliflozin/metformin FDC should also be administered with meals., (© 2018 The Authors. Clinical Pharmacology in Drug Development Published by Wiley Periodicals, Inc. on behalf of The American College of Clinical Pharmacology.)

Ertugliflozin, a selective sodium-glucose cotransporter-2 inhibitor, is being developed for the treatment of type 2 diabetes mellitus. This randomized, 6-sequence, 3-period crossover study assessed the effect of ertugliflozin (100 mg; supratherapeutic dose) vs placebo and moxifloxacin (400 mg; positive control) on the QT interval corrected for heart rate (QTc) in 42 male or female healthy subjects. Triplicate electrocardiograms were performed predose and serially over 48 hours postdose in each treatment period. The maximum observed least-squares mean (90% CI) difference in QTc using the Fridericia correction (QTcF) between ertugliflozin and placebo was 2.99 (1.68, 4.30) milliseconds, 24 hours postdose, below the 5-millisecond threshold of potential clinical concern. The upper limits of the 2-sided 90% CI were less than 10 milliseconds at all postdose time points. The lower 90% CIs for the least-squares mean QTcF difference between moxifloxacin and placebo were greater than 5 milliseconds at the preselected time points of 2, 3, and 4 hours postdose, establishing study sensitivity. The majority of adverse events were mild in severity. In healthy volunteers, at a supratherapeutic dose of 100 mg, ertugliflozin was not associated with QTc interval prolongation., (© 2018, The American College of Clinical Pharmacology.)

This study evaluated the absolute bioavailability of bosutinib and assessed its safety and tolerability after single-dose oral and intravenous administration. In this phase 1 open-label, 2-sequence, 2-period crossover study, healthy, fed subjects aged 18-55 years were randomized to 1 of 2 treatment sequences (n = 7/sequence): oral bosutinib (100 mg × 5) followed by intravenous bosutinib (120 mg in approximately 240 mL over 1 hour), with a ≥14-day washout, or intravenous bosutinib and then oral bosutinib. Results of plasma pharmacokinetics analyses demonstrated that exposure to intravenous bosutinib was 3-fold higher than for oral bosutinib (16.2 and 5.5 ng·h/mL/mg, respectively), and mean terminal half-life was similar (35.5 and 31.7 hours). The ratio of adjusted geometric means (90%CI) for the dose-normalized area under the plasma concentration-time profile (AUC 0-∞ /D) was 33.85% (30.65%-37.38%). Most treatment-emergent adverse events (AEs) were mild in severity. Gastrointestinal (GI) AEs occurred in 9 of 13 subjects given oral bosutinib, whereas no subjects given intravenous bosutinib experienced GI AEs, suggesting bosutinib present in the GI tract had an effect. Bosutinib exhibited an absolute bioavailability of 33.85% based on the ratio of AUC 0-∞ /D. Both oral and intravenous bosutinib were safe and well tolerated in healthy, fed adult subjects., (© 2017, The American College of Clinical Pharmacology.)

ALO-02 is an abuse-deterrent formulation consisting of capsules filled with pellets of extended-release oxycodone surrounding sequestered naltrexone. This randomized, double-blind, placebo-/active-controlled, 4-way crossover study examined the abuse potential of crushed ALO-02 administered intranasally to healthy, nondependent, recreational opioid users. Following drug discrimination and naloxone challenge, eligible participants (n = 32) entered a 4-way crossover treatment phase: crushed single dose of 1 of 2 placebos, ALO-02 30 mg/3.6 mg (oxycodone/naltrexone) or oxycodone immediate-release (IR) 30 mg. Primary end points were Drug Liking and High, measured on visual analog scales (VAS) summarized as maximum effect (Emax ) and effect occurring over 2 hours postdose (AUE0-2  h ). Crushed ALO-02 resulted in significantly lower scores versus oxycodone IR on Drug Liking (Emax , 60.5 vs 92.8; AUE0-2  h , 105.4 vs 160.0, respectively) and High (Emax , 25.2 vs 86.9; AUE0-2  h , 27.1 vs 136.4, respectively; n = 28; P < .0001). Adverse events occurred most frequently with oxycodone IR, followed by ALO-02, then placebo, and were considered mild and consistent with opioid therapy. Crushed ALO-02 administered intranasally to nondependent recreational opioid users resulted in significantly lower scores on Drug Liking/High VAS and other positive subjective measures versus crushed oxycodone IR, suggesting less abuse potential. Demonstration of actual abuse deterrence in the real world requires further research., (© 2015, The American College of Clinical Pharmacology.)

What Is Known and Objective: ALO-02 is being developed as an abuse-deterrent formulation of extended-release oxycodone hydrochloride with naltrexone hydrochloride sequestered in the core of pellets contained in capsules. The primary objective of this study was to assess the effects of administration of ALO-02 capsule whole under fed conditions or sprinkling the pellets from ALO-02 capsule on applesauce under fasting conditions on the pharmacokinetics (PK) of oxycodone, naltrexone and 6-ß-naltrexol compared with ALO-02 capsule administered whole under fasting conditions. The plasma naltrexone and 6-ß-naltrexol concentrations were used to assess the sequestration of naltrexone in the ALO-02 formulation. The secondary objective was to evaluate the safety and tolerability of single 40 mg doses of ALO-02 in healthy volunteers., Methods: This was an IRB-approved, open-label, single-dose, randomized, 3-period crossover study in 24 healthy adult volunteers, aged 18-55 years. Each subject was assigned to receive single 40 mg doses of ALO-02 administered whole (intact capsule) under fasting conditions, administered whole under fed conditions (high-fat breakfast ∼ 950 calories), or sprinkling the contents of the ALO-02 capsule (pellets) over applesauce and swallowing the dose without chewing under fasting conditions. Each treatment was separated by a 7-day washout interval. Plasma samples were analyzed just before dosing through 48 hours postdose for oxycodone, and through 120 hours postdose for naltrexone and its major metabolite, 6-ß-naltrexol. Pharmacokinetic parameters included maximum plasma concentration [Cmax ], area under the plasma concentration-time profile from time 0 to infinity [AUCinf ] and to the last quantifiable concentration [AUClast ], time to Cmax [Tmax ], and terminal half life [t1/2 ]. Adverse events, vital signs, and laboratory parameters were monitored for safety assessment., Results: The t1/2 and Tmax values for oxycodone were similar for all 3 treatments. There was a lack of effect of food (whole capsule, fed vs. fasted) or of sprinkling on applesauce (pellets vs. whole capsule, fasted) on oxycodone bioavailability. The Test/Reference ratios of adjusted geometric means for oxycodone AUCinf , AUClast , and Cmax were 99.2%, 100%, and 107%, respectively, for the effect of food; and 101%, 101%, and 97.5%, respectively, for the effect of sprinkling on applesauce. The 90% confidence intervals contained entirely within the bioequivalence limits of 80% to 125% for each comparison. Naltrexone remained sequestered during each treatment, based on the sporadic and low measurable plasma concentrations of naltrexone and 6-ß-naltrexol. Single doses of ALO-02 40 mg were well tolerated, and adverse events were mild, with no apparent difference in frequency for all 3 treatments., What Is New and Conclusion: Results indicate that ALO-02 can be administered without regard to food. Also, the contents of ALO-02 can be sprinkled over applesauce and consumed without chewing as an alternative treatment option by subjects with difficulty swallowing. Naltrexone remained sequestered in the ALO-02 formulation under all 3 treatments., (© 2015, The American College of Clinical Pharmacology.)

Safety, tolerability, and pharmacokinetics of tigecycline in 76 healthy Japanese subjects were determined in three randomized, double-blind, placebo-controlled studies. Subjects in an ascending single-dose study (n = 40) received 25-150 mg intravenously, whereas subjects in two multiple-dose studies received every 12-hour (q12h) dosing with 25 mg (n = 10) or 25, 50, or 100 then 50 mg (n = 30). Serial blood samples and urine were collected, drug concentrations determined, and pharmacokinetic parameters calculated. Fecal samples were also collected in the second multiple-dose study. After 10 days of tigecycline 50 mg q12h, mean ± standard deviation pharmacokinetics in 8/10 subjects were: maximum concentration 1,118 ± 127 ng/mL, area under the concentration-time curve 0-12 hours 3,261 ± 937 ng h/mL, clearance 0.25 ± 0.05 L/h/kg, half-life 60.7 ± 23.4 hours, and volume of distribution 11.9 ± 2.3 L/kg. The most common adverse events were nausea and vomiting. Changes in total bilirubin were also observed. Enterococci in the intestinal microflora were reduced, whereas the number of Enterobacteriaceae and Bacteroides remained relatively constant. Several strains of Bacteroides spp. resistant to tigecycline treatment were found in fecal samples on days 30 and 31. The pharmacokinetic profile of tigecycline was similar to non-Japanese subjects; tolerability and change in intestinal microflora were also similar., (© 2013, The American College of Clinical Pharmacology.)

In order to evaluate the potential for CYP3A4 induction by moxidectin, midazolam pharmacokinetic (PK) parameters were compared before and after moxidectin administration. Healthy subjects received a single 8 mg dose of moxidectin and 3 single 7.5 mg doses of midazolam 3 days before, and 7 and 89 days after the moxidectin. Blood samples were taken for 24 hours to measure midazolam and metabolites in plasma, and for 89 days to measure moxidectin in plasma after dose administration. Noncompartmental PK analyses were performed for each analyte. Analysis of variance was performed on log-transformed midazolam parameters with treatment day as a fixed effect. Adverse events were recorded and laboratory tests, physical examinations, pulse oximetry monitoring, vital sign measurement, and electrocardiograms performed. Thirty-nine subjects were enrolled in the study; PK data were available for 37 subjects. Moxidectin PK parameters were similar to previous studies. There were no significant changes in PK for midazolam or its metabolites 7 or 89 days after moxidectin administration. Adverse events were generally mild and there were no relevant changes in safety assessments. Thus, 8 mg moxidectin does not induce CYP3A4 activity and other CYP3A4 substrates are unlikely to be affected by moxidectin co-administration., (© 2013, The American College of Clinical Pharmacology.)

Sirolimus, metabolized primarily by intestinal and hepatic CYP3A4, is a substrate for P-glycoprotein. CYP3A4 inducers would be expected to decrease sirolimus exposure. This open-label, nonrandomized study investigated effects of CYP3A4 induction, by rifampin, on sirolimus pharmacokinetics. Healthy volunteers received sirolimus 20 mg on day 1. After washout period, multiple 600-mg rifampin doses were administered daily for 14 days. On day 9, one 20-mg sirolimus dose was administered after an overnight fast (≥10 hours). Whole blood samples for sirolimus collected for 144 hours after each dose were analyzed by liquid chromatography/tandem mass spectrometry. Pharmacokinetic parameters, assessed using noncompartmental methods, were compared using analysis of variance. Geometric mean ratios of Cmax and AUCinf were 29% (90% CI: 26, 32%) and 18% (90% CI: 16, 21%), respectively, with rifampin co-administration versus sirolimus alone. Corresponding decreases in Cmax and AUC were 71% and 82%, respectively, which would likely cause trough concentrations to fall below the recommended therapeutic range. Mean CL/F increased approximately fivefold with rifampin versus sirolimus alone. Co-administering sirolimus and potent CYP3A inducers is not recommended. If co-administration is necessary, dose adjustment and concentration monitoring should be conducted., (© 2013, The American College of Clinical Pharmacology.)

The pharmacokinetic parameters of tigecycline were assessed in subjects with severe renal impairment (creatinine clearance <30 mL/min, n = 6), subjects receiving hemodialysis (4 received tigecycline before and 4 received tigecycline after hemodialysis), and subjects with age-adjusted, normal renal function (n = 6) after administration of single 100-mg doses. Serial serum and urine samples were collected and assayed using validated liquid chromatography with tandem mass spectrometer (LC/MS/MS) methods. Concentration-time data were then analyzed using noncompartmental pharmacokinetic methods. Tigecycline renal clearance in subjects with normal renal function represented approximately 20% of total systemic clearance. Tigecycline clearance was reduced by approximately 20%, and area under the tigecycline concentration-time curve increased by approximately 30% in subjects with severe renal impairment. Tigecycline was not efficiently removed by dialysis; thus, it can be administered without regard to timing of hemodialysis. Based on these pharmacokinetic data, tigecycline requires no dosage adjustment in patients with renal impairment.

Availability of a lower dose tablet would add to the dosing flexibility of currently available 1- and 2-mg sirolimus tablets for optimal concentrations and patient compliance. A randomized, 3-period crossover study was conducted in 30 fasting healthy volunteers (29 men, aged 31 ± 8 years, weight 79 ± 12 kg). Subjects were given 5 mg of sirolimus, either as doses of the 0.5-mg nonshellac-core prototype, 0.5-mg shellac-core prototype, or approved 1-mg tablet. Whole blood samples were collected at selected time points for 144 hours after dosing and analyzed using LC/MS/MS assay. Noncompartmental pharmacokinetic analysis was performed, followed by bioequivalence assessment. Twenty-four subjects completed all dosing periods, and no formulation-associated adverse events were reported. Ratios of maximum plasma concentration (Cmax ), area under the concentration-time curve to the last measured concentration (AUCT ), and area under the concentration-time curve from time 0 to infinity (AUC) for the nonshellac-core prototype compared with the 1-mg tablet were within the 80% to 125% range dictated by bioequivalence conventions. Similar results were observed when comparing the ratios of AUCT and AUC for the shellac-core prototype, while 90% confidence interval of the ratio of Cmax values was 105% to 129%. Within the context of clinical equivalence standards established by a phase 3 study comparing liquid to tablet formulations, it was concluded that both prototypes were clinically bioequivalent to the reference formulation., (2012 American College of Clinical Pharmacology.)

Background and Purpose: This study was designed to establish the pathology-specific inhibitory effects of the IKur/Ito/IK,ACh blocker AVE0118 on atrium-selective channels and its corresponding effects on action potential shape and effective refractory period in patients with chronic AF (cAF)., Experimental Approach: Outward K+-currents of right atrial myocytes and action potentials of atrial trabeculae were measured with whole-cell voltage clamp and microelectrode techniques, respectively. Outward currents were dissected by curve fitting., Key Results: Four components of outward K+-currents and AF-specific alterations in their properties were identified. Ito was smaller in cAF than in SR, and AVE0118 (10 microM) apparently accelerated its inactivation in both groups without reducing its amplitude. Amplitudes of rapidly and slowly inactivating components of IKur were lower in cAF than in SR. The former was abolished by AVE0118 in both groups, the latter was partially blocked in SR, but not in cAF, even though its inactivation was apparently accelerated in cAF. The large non-inactivating current component was similar in magnitude in both groups, but decreased by AVE0118 only in SR. AVE0118 strongly suppressed AF-related constitutively active IK,ACh and prolonged atrial action potential and effective refractory period exclusively in cAF., Conclusions and Implications: In atrial myocytes of cAF patients, we detected reduced function of distinct IKur components that possessed decreased component-specific sensitivity to AVE0118 most likely as a consequence of AF-induced electrical remodelling. Inhibition of profibrillatory constitutively active IK,ACh may lead to pathology-specific efficacy of AVE0118 that is likely to contribute to its ability to convert AF into SR.

Nine subjects with severe hepatic impairment (Child-Pugh grade C) and 9 healthy matched control subjects were given a single 15-mg dose of sirolimus by oral solution. Increases (P < or = .002) in mean whole-blood sirolimus t(1/2) (168%), AUC(0-infinity) (210%), and MRT(oral) (261%), together with a decrease (P = .001) in CL/F (-67%), were observed in subjects with severe hepatic impairment compared with healthy matched controls. Sirolimus pharmacokinetic data in Child-Pugh grade A (n = 13, mild) and B (n = 5, moderate) subjects from a previous identically designed study were available for an inter-study comparison. Overall, mean t(1/2), weight-normalized AUC, and MRT(oral) increased steadily, whereas mean CL/F decreased steadily, with increasing degrees of hepatic impairment. CL/F showed large intersubject variabilities within subject types and extensive overlap among the subject types. The results of this study suggest that an initial sirolimus dose reduction of approximately 60% is appropriate in patients with acute severe hepatic impairment; this should be followed by further dose adjustment, based on therapeutic drug monitoring, until the trough concentrations have stabilized at sirolimus levels existing prior to the onset of acute liver failure.

Eighteen adult subjects with mild to moderate hepatic impairment and 18 healthy control subjects were given a single 15-mg dose of sirolimus by oral solution. Mean whole-blood sirolimus weight-normalized oral-dose clearances (CL/F) were significantly decreased (P = .02) in subjects with mild to moderate hepatic impairment by -31.8% and -36.0%, respectively, compared with controls. There were no significant differences in mean sirolimus C(max) and t(max) values among groups. The observed decreases in CL/F may be relevant in renal transplant patients with mild to moderate hepatic impairment, based on the close similarity of sirolimus CL/F in controls and previously studied stable renal transplant patients receiving multiple-dose administration of sirolimus and cyclosporine. There was considerable overlap in the CL/F values of hepatic-impaired subjects and controls, suggesting that whole-blood sirolimus trough concentrations in renal transplant patients exhibiting mild to moderate hepatic impairment be initially monitored to assess the need for dose adjustments.