Geometric Mean Ratios Of AUC Research Articles

Effects of the selective AMPA modulator NBI-1065845 on the pharmacokinetics of midazolam or ethinyl estradiol-levonorgestrel in healthy adults.

This parallel-arm, phase I study investigated the potential cytochrome P450 (CYP)3A induction effect of NBI-1065845 (TAK-653), an investigational α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor potentiator in phase II development for major depressive disorder. The midazolam treatment arm received the sensitive CYP3A substrate midazolam on Day 1, followed by NBI-1065845 alone on Days 5-13; on Day 14, NBI-1065845 was administered with midazolam, then NBI-1065845 alone on Day 15. The oral contraceptive treatment arm received ethinyl estradiol-levonorgestrel on Day 1, then NBI-1065845 alone on Days 5-13; on Day 14, NBI-1065845 was administered with ethinyl estradiol-levonorgestrel, then NBI-1065845 alone on Days 15-17. Blood samples were collected for pharmacokinetic analyses. The midazolam treatment arm comprised 14 men and 4 women, of whom 16 completed the study. Sixteen of the 17 healthy women completed the oral contraceptive treatment arm. After multiple daily doses of NBI-1065845, the geometric mean ratios (GMRs) (90% confidence interval) for maximum observed concentration were: midazolam, 0.94 (0.79-1.13); ethinyl estradiol, 1.00 (0.87-1.15); and levonorgestrel, 0.99 (0.87-1.13). For area under the plasma concentration-time curve (AUC) from time 0 to infinity, the GMRs were as follows: midazolam, 0.88 (0.78-0.98); and ethinyl estradiol, 1.01 (0.88-1.15). For levonorgestrel, the GMR for AUC from time 0 to the last quantifiable concentration was 0.87 (0.78-0.96). These findings indicate that NBI-1065845 is not a CYP3A inducer and support its administration with CYP3A substrates. NBI-1065845 was generally well tolerated, with no new safety signals observed after coadministration of midazolam, ethinyl estradiol, or levonorgestrel.

Study of the pharmacokinetics, pharmacodynamics, and safety of the biosimilar pembrolizumab RPH-075 compared to Keytruda® in patients with malignant neoplasms

Introduction: Pembrolizumab is a humanized monoclonal antibody selectively blocking the interaction between the PD-1 receptor and its ligands. The drug RPH-075 is a biosimilar to the original Keytruda®.Objective: To establish the equivalence of pharmacokinetic (PK) properties, as well as pharmacodynamic (PD) parameters, safety, and immunogenicity of the drug RPH-075 compared to Keytruda® in patients with malignant tumors.Materials and Methods: This multicenter double-blind randomized study included 90 patients with melanoma and non-small cell lung cancer who were randomized into two treatment groups (RPH-075 and Keytruda ®) in 1:1 ratio. In both groups, pembrolizumab was administered as monotherapy at a dose of 200 mg intravenously every 3 weeks until progression or intolerable toxicity. The primary aim of the study was to assess PK after the first administration. The primary endpoint for PK assessment was AUC(0–504), and for safety, it was the frequency of adverse events (AE). The decision on PK equivalence was planned to be made if the two-sided 90 % confidence interval (CI) for the geometric mean ratio of AUC(0–504) after a single administration of each drug would be within 80.00–125.00 %. Secondary endpoints included Cmax after the first administration, as well as the other PK, safety, and immunogenicity parameters. This study also assessed PK and PD parameters after multiple administrations, and a pilot efficacy assessment was planned.Results: This article presents the analysis of data from the first stage of the study (after the first drug administration with a 3‑week observation period). The data analysis was blinded, and the treatment groups were coded as A and B. The 90 % CI for the geometric mean ratio of AUC(0–504) after the administration of drug A to AUC(0–504) of drug B was 93.50–121.16 %, and for the ratio of B to A, it was 82.54–106.95 %. The obtained intervals met the specified equivalence limit of 80.00–125.00 %, allowing us to conclude that RPH-075 and original Keytruda® are PK equivalent. Both drugs demonstrated comparably high saturation of PD-1 receptors on CD4+ / CD8+ lymphocytes at the end of the first cycle (day 22). Binding antibodies to pembrolizumab were detected in 2 patients (one in each group) over the analyzed period, indicating comparably low immunogenicity for both drugs. Safety profile analysis during this period revealed 7 AEs in 4 patients in group A and 4 AEs in 3 patients in group B. The frequency of AEs did not significantly differ between the groups.Conclusions: PK, PD, immunogenicity, and safety parameters of the pembrolizumab biosimilar RPH-075 were equivalent to those of the original Keytruda®.

Cytochrome P450 activity in rheumatoid arthritis patients during continuous IL-6 receptor antagonist therapy

BackgroundInflammation suppresses cytochrome P450 (CYP) enzyme activity, and single-dose interleukin 6 receptor antagonists (anti-IL-6R) reverse this effect. Here, we assess the impact of continuous anti-IL-6R therapy in patients with rheumatoid arthritis.MethodsIn a clinical pharmacokinetic trial, the Basel cocktail was administered before and after 3 and 12 weeks of anti-IL-6R therapy to assess CYP enzyme activity (registered in the ClinicalTrials.gov database (identifier NCT04842981) on April 13th, 2021). In a retrospective study, the 4β-hydroxycholesterol/cholesterol ratio was measured as a biomarker for CYP3A4 activity before and after 3 and 6 months of anti-IL-6R therapy. The control group was patients initiating a tumor necrosis factor alfa (TNF-α) inhibitor.ResultsIn the clinical pharmacokinetic trial (n = 3), midazolam metabolic ratio (CYP3A4) was inconclusive due to the limited sample size. Midazolam AUC and Cmax indicate a weak impact on CYP3A4 activity after 3 weeks of anti-IL-6R therapy compared to baseline (AUC geometric mean ratio (GMR): 0.80, 95% CI: 0.64–0.99 and Cmax GMR: 0.58, 95% CI: 0.37–0.91), which returns to baseline levels after 12 weeks of therapy (AUC GMR 1.02, 95% CI: 0.72–1.46 and Cmax GMR 1.03, 95% CI 0.72–1.47). No effect on the 4β-hydroxycholesterol/cholesterol ratio was observed in the retrospective study.ConclusionBased on sparse data from three patients, continuous anti-IL-6R therapy seems to cause an acute but transient increase in CYP3A4 activity in rheumatoid arthritis patients, which may be due to a normalization of the inflammation-suppressed CYP activity. Further studies are warranted to understand the mechanism behind this putative transient effect.Trial registration Registered in the ClinicalTrials.gov database (identifier NCT04842981) on April 13th, 2021.

Pharmacokinetics of cenobamate as monotherapy compared with adjunctive therapy

ObjectiveCenobamate was approved by the US Food and Drug Administration (FDA) based on studies of adjunctive therapy in patients with focal epilepsy. To support the use of cenobamate monotherapy, this pharmacokinetic (PK)-based simulation analysis evaluated the predicted PK exposure of cenobamate when used as monotherapy versus adjunctive therapy. MethodsA population pharmacokinetic (PopPK) model of cenobamate was developed using pooled human data from eight phase 1 studies in healthy subjects or special populations, and three phase 2 and 3 studies in patients with focal seizures (N = 960). Concomitant antiseizure medications (ASMs) with a statistically significant effect on the apparent systemic clearance (CL/F) of cenobamate in the PopPK model were used to compare simulated patient plasma exposures (area under the plasma concentration vs time curve [AUC]) following monotherapy versus adjunctive therapy. Treatment equivalence between monotherapy and adjunctive therapy was concluded if the 90% confidence interval (CI) of the geometric mean AUC ratio was within 0.8–1.25. ResultsIn the PopPK model, statistically significant effects on cenobamate CL/F were shown for clobazam (decreased cenobamate CL/F by 19%) and carbamazepine (increased cenobamate CL/F by 15%); these differences were not considered clinically meaningful. Other ASMs (lacosamide, lamotrigine, levetiracetam, oxcarbazepine, topiramate, and valproate) when coadministered with cenobamate did not have significant effects on the disposition (ie, PK or efficacy) of cenobamate. The geometric mean ratio (90% CIs) of cenobamate AUC for adjunctive therapy/monotherapy was 0.87 (0.816–0.925) for adjunctive carbamazepine and 1.24 (1.147–1.339) for adjunctive clobazam. The 90% CI was within the no-effect limits (90% CIs 0.8–1.25) for adjunctive carbamazepine and partially exceeding no-effect limits for adjunctive clobazam. ConclusionsBased on the results from this PopPK analysis, cenobamate monotherapy can be expected to result in comparable exposures to those that have been demonstrated to be safe and effective when used as adjunctive therapy for the treatment of focal seizures, supporting the use of cenobamate as monotherapy in these patients.

PBPK perspective on alternative CYP3A4 inducers for rifampin.

PBPK perspective on alternative CYP3A4 inducers for rifampin.

Physiologically Based Absorption Modelling to Explore the Formulation and Gastric pH Changes on the Pharmacokinetics of Acalabrutinib.

Acalabrutinib, a selective Bruton's tyrosine kinase inhibitor, is a biopharmaceutics classification system class II drug. The aim of this study was to develop a physiologically based pharmacokinetic (PBPK) model to mechanistically describe absorption of immediate release capsule formulation of acalabrutinib in humans. Integration of in vitro biorelevant measurements, dissolution studies and in silico modelling provided clinically relevant inputs for the mechanistic absorption PBPK model. The batch specific dissolution data were integrated in two ways, by fitting a diffusion layer model scalar to the drug product dissolution with integration of drug substance laser diffraction particle size data, or by fitting a product particle size distribution to the dissolution data. The latter method proved more robust and biopredictive. In both cases, the drug surface solubility was well predicted by the Simcyp simulator. The model using the product particle size distribution (P-PSD) for each clinical batch adequately captured the PK profiles of acalabrutinib and its active metabolite. Average fold errors were 0.89 for both Cmax and AUC, suggesting good agreement between predicted and observed PK values. The model also accurately predicted pH-dependent drug-drug interactions between omeprazole and acalabrutinib, which was similar across all clinical formulations. The model predicted acalabrutinib geometric mean AUC ratios (with omeprazole vs acalabrutinib alone) were 0.51 and 0.68 for 2 batches of formulations, which are close to observed values of 0.43 and 0.51~0.63, respectively. The mechanistic absorption PBPK model could be potentially used for future applications such as optimizing formulations or predicting the PK for different batches of the drug product.

1122. Effect of Aluminum Hydroxide/Magnesium Hydroxide/Simethicone and Omeprazole on the Pharmacokinetics of Tebipenem Pivoxil Hydrobromide (TBP-PI-HBr) in Healthy Adult Subjects

BackgroundTebipenem pivoxil hydrobromide (TBP-PI-HBr) is an oral prodrug that is converted to tebipenem (TBP), the active moiety being developed for treating complication urinary tract infections. Antacids and proton pump inhibitors are known to change gastric pH after administration, which could affect the absorption of oral medications. This study evaluated the effect of a single dose of aluminum hydroxide/magnesium hydroxide/simethicone and the effect of multiple doses of omeprazole on the PK of TBP, following a single dose of TBP-PI-HBr.MethodsThis was an open-label, 3-period, fixed sequence drug-drug interaction study. On Day 1, Period 1, subjects received a single oral dose of TBP-PI-HBr 600 mg (2 x 300 mg tablets) at Hour 0. On Day 1, Period 2, subjects received a single oral 20 mL dose of aluminum hydroxide 800 mg/magnesium hydroxide 800 mg/simethicone 80 mg suspension per 10 mL (Maalox® Advanced Maximum Strength oral suspension) with a single oral dose of TBP-PI-HBr 600 mg at Hour 0. In Period 3, on Days 1 through 5, subjects received a single oral dose of omeprazole 40 mg (Prilosec®) once daily (QD), at Hour -2. On Day 5, a single oral dose of 600 mg TBP-PI-HBr was administered at Hour 0. Whole blood sampling for TBP PK occurred pre-dose and up to 24 hours post dose. Whole blood samples were assayed for TBP by liquid chromatography-tandem mass spectrometry.ResultsTwenty subject were enrolled and completed the study. Geometric mean ratios for AUC indicated mean TBP exposure (AUC) was approximately 11% lower and mean Cmax was 22% lower for TBP-PI-HBr combined with aluminum hydroxide/magnesium hydroxide/simethicone vs. TBP-PI-HBr alone (Figure). Similarly, geometric mean ratios for AUC indicated mean TBP exposure (AUC) was approximately 11% lower and mean Cmax was 43% lower for TBP-PI-HBr in combination with omeprazole vs. TBP-PI-HBr alone. Because the PK/PD driver for TBP efficacy is AUC dependent, concomitant administration is not expected to impact the efficacy of oral TBP-PI-HBr. Figure 1. Arithmetic mean plasma TBP concentrations following a 600 mg dose of clinical study drug product (A1 and A2) and registrational drug product (B) – PK population.ConclusionAdministration of TBP-PI-HBr combined with aluminum hydroxide/magnesium hydroxide/simethicone or omeprazole QD had no meaningful effect on plasma TBP exposure; Cmax decreased with both agents. Co-administration was generally safe and well tolerated.Disclosures Vipul K. Gupta, Ph.D., Spero Therapeutics (Employee, Shareholder) Gina Patel, PhD, Spero Therapeutics, Inc. (Consultant) Leanne Gasink, MD, Spero Therapeutics, Inc. (Consultant) Floni Bajraktari, MSc, Spero Therapeutics, Inc. (Employee) Yang Lei, PhD, Spero Therapeutics, Inc. (Employee) Akash Jain, PhD, Spero Therapeutics, Inc. (Employee) Praveen Srivastava, MS, BS, Spero Therapeutics, Inc. (Employee) Angela Talley, MD, Spero Therapeutics, Inc. (Employee)

Effect of Particle Size and Viscosity of Suspensions on Topical Ocular Bioavailability of Budesonide, a Corticosteroid.

Purpose: To determine the effect of particle size and viscosity of suspensions on topical ocular bioavailability of budesonide, a corticosteroid drug. Methods: Budesonide microparticle and nanoparticle (MP and NP) suspensions were prepared with or without homogenization and microfluidization. Using different grades of hydroxyl propyl methyl cellulose, low viscosity NP (NP-LV) and low and high viscosity MP (MP-LV and MP-HV) were prepared. Suspensions were characterized for particle size, viscosity, and osmolality. Budesonide suspensions were administered topically to rabbits and aqueous humor was collected and analyzed for budesonide. Budesonide Cmax, tmax, and the area under the concentration time curve (AUC (0-6h)) values were determined. The geometric mean ratio of AUC and bioequivalence was evaluated using a bootstrap method. Results: The particle sizes for NP and MP were ∼700 and 2,000 nm. The viscosities for low and HV formulations were ∼5 and 50 cP. The geometric mean budesonide Cmax values for the suspensions NP-LV, MP-LV, and MP-HV were 0.22, 0.22, and 0.31 μg/g, tmax values were 0.67, 0.60 and 0.53 h, and AUC0-6h values were 0.72, 0.53, and 0.95 μg h/g, respectively. Bootstrap analysis indicated that the 90% confidence intervals of the geometric mean ratio of AUC0-6h values were 1.00-1.74 (MP-HV vs. NP-LV), 0.57-0.96 (MP-LV vs. NP-LV), and 0.45-0.70 (MP-LV vs. MP-HV). Conclusions: The 3 budesonide suspensions assessed in this study were not bioequivalent. Results suggested that an increase in viscosity improves the bioavailability of budesonide from the microsuspension formulation.

The Effect of Food on the Absorption of Abiraterone Acetate from a Fine Particle Dosage Form: A Randomized Crossover Trial in Healthy Volunteers

Abiraterone acetate (AA) is approved for treatment of metastatic castration-resistant prostate cancer. The originator AA (OAA) formulation has been associated with AUC and C max increases of 10- and 17-fold, respectively, when administered following a high-fat meal relative to the fasted state. AA fine particle (AAFP) is a proprietary formulation (utilizing SoluMatrix Fine Particle Technology™) that has enhanced dissolution properties. It was designed to increase the oral bioavailability of AA, and to potentially reduce variability in drug exposure and food effects compared with OAA. In healthy subjects, AAFP 500 mg was previously shown to be bioequivalent to OAA 1000 mg when taken in fasted conditions. Healthy male subjects (N = 25) fasted 10 h overnight before randomization in a crossover design received a single 500-mg dose of AAFP under fasted or fed conditions. The extent of AAFP drug exposure was significantly (P < 0.001) greater under fed versus fasted conditions. Following a single dose of AAFP, relative bioavailability measured by the geometric mean ratio of AUC and C max of abiraterone indicated that the extent of drug absorption increased under fed conditions by approximately 4.5- and 6.5-fold, respectively, versus under fasted conditions. AAFP was safe and well-tolerated. AAFP under fed conditions has higher bioavailability and is not bioequivalent to AAFP under fasted conditions. The food effect with AAFP 500 mg was approximately 50% less than what has been reported for OAA 1000 mg. Although diminished, the potential for excessive abiraterone plasma concentrations in patients who are noncompliant with dosing instructions remains. Churchill Pharmaceuticals LLC.

Effect of Low-Furanocoumarin Hybrid Grapefruit Juice Consumption on Midazolam Pharmacokinetics.

The objectives of this study were to investigate the effect of grapefruit juice low in furanocoumarins on CYP3A activity and to summarize previous findings of enzyme inhibition measured by the metabolism of midazolam after intake of grapefruit juice. Twelve healthy volunteers participated in a prospective, randomized, double-blinded, 3-way crossover clinical study to determine the effect of regular grapefruit juice (RGJ) and a novel, low-furanocoumarin hybrid grapefruit juice (HGJ) on the metabolism of oral midazolam, used as a probe for in vivo CYP3A activity, compared with water as a control. The RGJ was 100% hand-squeezed "Hudson" grapefruit juice, and the HGJ contained low amounts of furanocoumarin constituents. The point estimates (90% confidence intervals) for the RGJ/water midazolam AUC geometric mean ratio was 122% (107-140). The point estimate for the HGJ/water midazolam AUC ratio was within the 80% to 125% bioequivalence range, indicating an absence of interaction. This finding also prompted a systematic review of available evidence on the pharmacokinetic alteration of midazolam by grapefruit juice. Although most studies demonstrated alteration in midazolam pharmacokinetics supporting inhibition of CYP3A activity as a likely mechanism, the cohorts included in these studies and the extent of the pharmacokinetic interaction varied widely. The current study indicated grapefruit juice-drug interaction varies substantially based on patient characteristics and/or grapefruit juice product-related factors, including the amount of furanocoumarin constituents present in the juice.

Evaluation of Mutual Drug-Drug Interaction within Geneva Cocktail for Cytochrome P450 Phenotyping using Innovative Dried Blood Sampling Method.

Cytochrome P450 (CYP) activity can be assessed using a 'cocktail' phenotyping approach. Recently, we have developed a cocktail (Geneva cocktail) which combines the use of low-dose probes with a low-invasiveness dried blood spots (DBS) sampling technique and a single analytical method for the phenotyping of six major CYP isoforms. We have previously demonstrated that modulation of CYP activity after pre-treatment with CYP inhibitors/inducer could be reliably predicted using Geneva cocktail. To further validate this cocktail, in this study, we have verified whether probe drugs contained in the latter cause mutual drug-drug interactions. In a randomized, four-way, Latin-square crossover study, 30 healthy volunteers received low-dose caffeine, flurbiprofen, omeprazole, dextromethorphan and midazolam (a previously validated combination with no mutual drug-drug interactions); fexofenadine alone; bupropion alone; or all seven drugs simultaneously (Geneva cocktail). Pharmacokinetic profiles of the probe drugs and their metabolites were determined in DBS samples using both conventional micropipette sampling and new microfluidic device allowing for self-sampling. The 90% confidence intervals for the geometric mean ratios of AUC metabolite/AUC probe for CYP probes administered alone or within Geneva cocktail fell within the 0.8-1.25 bioequivalence range indicating the absence of pharmacokinetic interaction. The same result was observed for the chosen phenotyping indices, that is metabolic ratios at 2 hr (CYP1A2, CYP3A) or 3 hr (CYP2B6, CYP2C9, CYP2C19, CYP2D6) post-cocktail administration. DBS sampling could successfully be performed using a new microfluidic device. In conclusion, Geneva cocktail combined with an innovative DBS sampling device can be used routinely as a test for simultaneous CYP phenotyping.

Investigation of Potential Pharmacodynamic and Pharmacokinetic Interactions Between Selexipag and Warfarin in Healthy Male Subjects

PurposeSelexipag is a new orally available nonprostanoid prostacyclin receptor agonist for the treatment of pulmonary arterial hypertension. Warfarin is commonly used in patients with pulmonary arterial hypertension. Possible pharmacodynamic and pharmacokinetic interactions between selexipag and warfarin in healthy individuals were investigated. MethodsThis was a double-blind, 2-way, 2-treatment crossover, Phase I study. Nineteen healthy men received a single dose of selexipag 400 μg or placebo on day 1, followed by selexipag 400 μg or placebo BID on days 2 to 12. A concomitant single dose of warfarin 20 mg was administered in the morning of day 8. FindingsBoth treatments were well tolerated. The most frequently reported adverse event was headache in both treatments. Geometric mean ratios and 90% CIs of the maximum international normalized ratio (geometric mean ratio = 0.96; 90% CI, 0.90–1.03) and international normalized ratio AUC0–144h (geometric mean ratio = 0.98; 90% CI, 0.96–1.00)] during treatment with warfarin and selexipag versus treatment with only warfarin were inside the reference limits of 0.80 to 1.25. The 90% CIs of the geometric mean ratios of AUC and Cmax for R- and S-warfarin during treatment with warfarin and selexipag versus treatment with warfarin alone were inside the reference range of 0.80 to 1.25. After repeated-dose administration of 400 μg selexipag, the AUC of selexipag and its active metabolite, ACT-333679, at steady state were not affected by a single dose of 20 mg warfarin. ImplicationsSteady-state levels of selexipag and ACT-333679 after repeated doses of 400 μg selexipag had no influence on the warfarin pharmacodynamic variables. There was no pharmacokinetic interaction between selexipag and warfarin.

Multiple-Dose Study to Evaluate Pharmacokinetics, Pharmacodynamics, and Safety in Healthy Subjects: A Comparison of Controlled-Release Sarpogrelate and Immediate-Release Sarpogrelate

Aims: To compare the pharmacokinetics, pharmacodynamics, and safety of sarpogrelate between controlled-release (CR) and immediate-release (IR) formulations after multiple-dose administration. Methods: This study was a randomized, open-label, 2-period, 2-treatment, crossover study in healthy subjects. All subjects received CR sarpogrelate 300 mg once daily and IR sarpogrelate 100 mg three times daily by random order each for 3 days with a 7-day washout period. Serial blood sampling was performed over 24 h. Pharmacokinetic parameters were determined by noncompartmental methods. Platelet aggregation to collagen, measured by light transmission aggregometry, was reported as maximal platelet aggregation. Results: Thirty-two subjects completed the study. CR sarpogrelate increased rapidly, reaching C_max in 1.25 h (vs. 1.00 h in IR sarpogrelate) and declined with a t_1/2 of 3.59 h (vs. 1.12 h in IR sarpogrelate). The 90% CIs for the geometric mean ratio of AUC_τ and C_max,ss between IR and CR formulations were 1.18 to 1.40 and 0.99 to 1.29, respectively. The degree of inhibition of platelet aggregation was similar between two formulations. Conclusions: CR sarpogrelate showed slightly higher systemic exposure and similar peak concentration compared with IR sarpogrelate. The profiles of pharmacodynamics and safety were comparable between two formulations.

Effect of lopinavir/ritonavir on the pharmacokinetics of selexipag an oral prostacyclin receptor agonist and its active metabolite in healthy subjects.

This study investigated the effect of a fixed dose combination of lopinavir/ritonavir on the pharmacokinetics (PK) of selexipag and its active metabolite ACT-333679. This was an open label, randomized, single centre, two way, crossover study. Twenty healthy male subjects were treated with a single dose of 400 µg selexipag alone and in combination with multiple doses of lopinavir/ritonavir (400/100 mg) twice daily. The results showed that lopinavir/ritonavir approximately doubled the exposure to selexipag. The area under the plasma concentration-time curve from time zero to infinity (AUC(0,∞) and the maximum plasma concentration (Cmax) of selexipag were 2.2- and 2.1-fold higher, respectively, than under selexipag alone, with a 90% confidence interval (CI) of the geometric mean ratio (GMR) of 1.9, 2.7 and 1.7, 2.6, respectively. For ACT-333679, the clinically more relevant component of selexipag, systemic exposure was increased by 8% (GMR of AUC(0,∞) 1.1, 90% CI 0.9, 1.3), when lopinavir/ritonavir was co-administered with selexipag. The most frequently reported adverse event (AE) was headache. A single dose of selexipag, administered either alone or together with multiple doses of lopinavir/ritonavir, was safe and well tolerated. Lopinavir/ritonavir does not affect the PK parameters of selexipag and ACT-333679 to a clinically relevant extent. Therefore, adaptation of the selexipag dose is not required when co-administered with inhibitors of the organic anion-transporting polypeptide (OATP) 1B1/ 1B3, P-glycoprotein (P-gp) and/or CYP3A4.

Effect of food on the pharmacokinetics of canagliflozin/metformin (150/1,000 mg) immediate-release fixed-dose combination tablet in healthy participants.

To assess the effect of food on the pharmacokinetics (PK) of canagliflozin and metformin following administration of a canagliflozin/metformin (150/1,000 mg) immediate-release (IR) fixed-dose combination (FDC) tablet. A randomized, open-label, singlecenter, single-dose, 2-period, 2-sequence crossover study was conducted in healthy participants. Participants were randomized to 2 sequences of fasted and fed (or vice versa) administration of one 150/1,000 mg canagliflozin/metformin IR FDC, with 10-14 day washout between treatments PK parameters (AUC, Cmax, tmax, t1/2) were assessed for canagliflozin and metformin. Safety was evaluated. When comparing the IR FDC tablet administered with and without food, PK parameters of canagliflozin were bioequivalent as the 90% confidence intervals (CIs) for log-transformed AUClast, AUC∞, and Cmax were within the bioequivalence limits of 80-125%. For metformin, overall exposure was similar under fed and fasted conditions as geometric mean ratios for AUC and associated 90% CI were contained within the bioequivalence limits, but geometric mean Cmax decreased by 16% in the fed compared to fasted state. Both treatments were well tolerated with similar adverse events and most common were gastrointestinal events, generally attributed to metformin. Food did not affect canagliflozin bioavailability parameters (Cmax and AUCs) or AUCs of metformin. The Cmax of metformin was decreased by 16%, which is not considered clinically meaningful. The canagliflozin/metformin FDC tablet is recommended to be taken with meals to reduce the symptoms of gastrointestinal intolerability associated with metformin.

Assessing Pharmacokinetic Interactions Between the Sodium Glucose Cotransporter 2 Inhibitor Empagliflozin and Hydrochlorothiazide or Torasemide in Patients With Type 2 Diabetes Mellitus: A Randomized, Open-Label, Crossover Study

PurposeEmpagliflozin is a potent, selective sodium glucose cotransporter 2 inhibitor approved for the treatment of type 2 diabetes mellitus. Thiazide or loop diuretics are commonly prescribed in patients with type 2 diabetes mellitus. This study investigated potential pharmacokinetic drug−drug interactions between empagliflozin and hydrochlorothiazide (HCTZ) or torasemide (TOR). MethodsThis was an open-label, crossover study. Patients with type 2 diabetes mellitus were randomized to receive empagliflozin 25 mg once daily for 5 days and either HCTZ 25 mg once daily for 4 days followed by HCTZ 25 mg once daily plus empagliflozin 25 mg once daily for 5 days or TOR 5 mg once daily for 4 days followed by TOR 5 mg once daily plus empagliflozin once daily for 5 days in 1 of 4 sequences, with at least a 7-day washout period between treatments. Pharmacokinetic parameters of empagliflozin, HCTZ, and TOR were assessed and standard bioequivalence criteria (80%−125%) were applied. Tolerability assessments included the frequency of adverse events and an investigator assessment of global tolerability. FindingsMean (SD) age of the 22 patients treated was 54.0 (8.1) years and body mass index was 27.1 (3.7) kg/m2. Coadministration of empagliflozin with HCTZ or TOR had no effect on exposure to empagliflozin, HCTZ, or TOR. Geometric mean ratios (90% CIs) for empagliflozin AUC over a uniform dosing interval and Cmax at steady state were 107.1% (90% CI, 97.1−118.1) and 102.8% (90% CI, 88.6−119.3), respectively, when coadministered with HCTZ versus administration alone, and 107.8% (90% CI, 100.1−116.1) and 107.5% (90% CI, 97.9−118.0), respectively, when coadministered with TOR versus administration alone. For HCTZ, the geometric mean ratios for AUC over a uniform dosing interval and Cmax at steady state were 96.3% (90% CI, 89.1−104.0) and 101.8% (90% CI, 88.6−116.9), respectively, and for TOR were 101.4% (90% CI, 99.1−103.9) and 104.4% (90% CI, 93.8−116.3), respectively, for combined treatment versus administration alone. The pharmacokinetic profiles of empagliflozin, HCTZ, and TOR were similar after administration alone and in combination. Global tolerability was good for all patients after each treatment, and no severe or serious adverse events were reported. ImplicationsNo pharmacokinetic drug−drug interaction was observed between empagliflozin and HCTZ or TOR. ClinicalTrials.gov identifier: NCT01276288.

Assessment of cytochrome P450-mediated drug-drug interaction potential of orteronel and exposure changes in patients with renal impairment using physiologically based pharmacokinetic modeling and simulation.

Orteronel is a nonsteroidal, selective inhibitor of 17,20-lyase that was recently in phase 3 clinical development as a treatment for castration-resistant prostate cancer. In humans, the primary clearance route for orteronel is renal excretion. Human liver microsomal studies indicated that orteronel weakly inhibits CYP1A2, 2C8, 2C9 and 2C19, with IC50 values of 17.8, 27.7, 30.8 and 38.8 µm, respectively, whereas orteronel does not inhibit CYP2B6, 2D6 or 3A4/5 (IC50 > 100 µm). Orteronel also does not exhibit time-dependent inhibition of CYP1A2, 2B6, 2C8, 2C9, 2C19, 2D6 or 3A4/5. The results of a static model indicated an [I]/Ki ratio >0.1 for CYP1A2, 2C8, 2C9 and 2C19. Therefore, a physiologically based pharmacokinetic (PBPK) model was developed to assess the potential for drug-drug interactions (DDIs) between orteronel and theophylline, repaglinide, (S)-warfarin and omeprazole, which are sensitive substrates of CYP1A2, 2C8, 2C9 and 2C19, respectively. Simulation of the area under the plasma concentration-time curve (AUC) of these four CYP substrates in the presence and absence of orteronel revealed geometric mean AUC ratios <1.25. Therefore, in accordance with the 2012 US FDA Draft Guidance on DDIs, orteronel can be labeled a 'non-inhibitor' and further clinical DDI evaluation is not required. In PBPK models of moderate and severe renal impairment, the AUC of orteronel was predicted to increase by 52% and 83%, respectively. These results are in agreement with those of a clinical trial in which AUC increases of 38% and 87% were observed in patients with moderate and severe renal impairment, respectively.

Effect of Ketoconazole on Lobeglitazone Pharmacokinetics in Korean Volunteers

PurposeLobeglitazone, a peroxisome proliferator–activated receptor-γ agonist, is metabolized primarily by the cytochrome P450 (CYP) 3A4 isoenzyme. Individuals concomitantly taking lobeglitazone and a CYP3A4 inhibitor may experience some adverse effects secondary to increased systemic exposure to lobeglitazone. To address such potential concern, we evaluated the effects of ketoconazole, a prototypic CYP3A4 inhibitor, on the pharmacokinetic (PK) properties and associated adverse effects of lobeglitazone. MethodsA PK drug-drug interaction study was conducted in healthy individuals between 20 and 45 years old in a randomized, open-label, 2-way crossover design. Even though the PK study was performed on a single dose of lobeglitazone, multiple ketoconazole doses were given to ensure that the full extent of inhibition of CYP3A4 was maintained during the PK sampling. All study participants received a single oral dose of lobeglitazone 0.5 mg with or without 9 oral 200-mg doses of ketoconazole pretreatment twice daily. The primary PK parameter end points (AUC and Cmax) were estimated using noncompartmental analysis, and the 90% CIs for the geometric mean ratios (ratio of lobeglitazone and ketoconazole to lobeglitazone alone) were investigated. Tolerability (adverse events, vital signs, ECG, and laboratory tests) was also assessed. FindingsA total of 24 Korean men (mean age, 26 years; age range, 20-32 years; mean weight, 68 kg; weight range, 59-81 kg) completed the study and were evaluable for lobeglitazone PK properties and tolerability. The mean (SD) Cmax values of lobeglitazone with and without ketoconazole were 49 (7) ng/mL and 48 (6) ng/mL at 1.5 and 1.0 hours after dosing, respectively. The mean (SD) AUC∞ values were 532 (117) ng·h/mL and 405 (110) ng·h/mL, respectively. Although the Cmax was not significantly affected, the geometric mean ratio for AUC∞ was increased by a point estimate of 1.33 (90% CI, 1.23-1.44). A single oral administration of lobeglitazone 0.5 mg with or without ketoconazole pretreatment did not produce any clinically significant adverse effects on vital signs, 12-lead ECG profiles, or laboratory tests. ImplicationsThe administration of lobeglitazone, 0.5 mg alone or in combination with multiple doses of ketoconazole, was generally well tolerated. The systemic exposure of lobeglitazone was increased to a modest extent by pretreatment with 9 twice-daily doses of ketoconazole. Clinicaltrials.gov identifier: NCT01330563

Metabolite parameters as an appropriate alternative approach for assessment of bioequivalence of two verapamil formulations.

A bioequivalence study of two verapamil formulations (generic verapamil tablets and Isoptin(®) tablets) was performed by comparing pharmacokinetic parameters of the parent drug and its major metabolite, norverapamil following a single dose administration of 80 mg verapamil hydrochloride in 22 healthy volunteers according to a randomized, two-period, crossover-design study. Moreover, the feasibility of proving bioequivalence of verapamil oral dosing form by means of norverapamil pharmacokinetic parameters was evaluated. Concentrations of verapamil and norverapamil were quantified in plasma using a validated high-performance liquid chromatography (HPLC) with fluorescence detection. The 90% CIs for the log-transformed ratios of verapamil Cmax (maximum plasma concentration) and AUC0-∞(area under the plasma concentration-versus-time curve from time zero to the infinity) were 73 to 101 and 80 to 103, respectively. Similarly, the corresponding ranges for norverapamil were 80-100 and 84-103, respectively. According to the parent drug data, the 90% confidence intervals around the geometric mean ratio of AUC happened to fit within preset bioequivalence limits of 80-125%, whereas those for Cmax did not. The 90% confidence intervals for both Cmax and AUC of norverapamil met preset bioequivalence limits. The AUC and Cmax of metabolite, when compared to parent drug, showed a much lower degree of variability and the 90% confidence intervals of the metabolite were therefore narrower than those of the parent drug. These observations indicate that bioequivalence studies using metabolite, norverapamil, could be a more suitable and preferable approach to assess bioequivalence of verapamil formulations due to its much lower variability and therefore lower number of volunteers that are required to conduct the study.

Pharmacokinetics of Coadministered Guanfacine Extended Release and Lisdexamfetamine Dimesylate

BackgroundIn clinical practice, α2-adrenoceptor agonists have been adjunctively administered with psychostimulants for the treatment of attention-deficit/hyperactivity disorder (ADHD). Two studies have examined the adjunctive use of guanfacine extended release (GXR, Intuniv®; Shire Development LLC, Wayne, PA, USA) with psychostimulants in children and adolescents with a suboptimal response to psychostimulant treatment. However, the potential for pharmacokinetic drug–drug interactions (DDIs) between GXR and lisdexamfetamine dimesylate (LDX, Vyvanse®; Shire US LLC, Wayne, PA, USA) has not been thoroughly evaluated.ObjectiveThe primary objective of this study was to examine the pharmacokinetics of GXR 4 mg and LDX 50 mg given as single doses alone and in combination.Study DesignThis was an open-label, randomized, three-period crossover, DDI study.SettingThe study was conducted in a single clinical research center.ParticipantsForty-two healthy adults were randomized in this study.InterventionsSubjects were administered single oral doses of GXR 4 mg, LDX 50 mg, or GXR and LDX in combination.Main Outcome MeasuresBlood samples collected predose and up to 72 h postdose assessed guanfacine, LDX, and d-amphetamine levels. Bioequivalence was defined as the 90 % confidence intervals (CIs) of the geometric mean ratios of the area under the plasma concentration–time curve extrapolated to infinity (AUC0–∞) and maximum plasma concentration (C max) falling within the bioequivalence reference interval (0.80–1.25). Safety measures included adverse events, vital signs, and electrocardiograms (ECGs).ResultsForty subjects completed the study. Following administration of LDX alone or in combination with GXR, the statistical comparisons of the AUC0–∞ and C max of d-amphetamine fell entirely within the reference interval. For guanfacine, the 90 % CI of the geometric mean ratio of AUC∞ for the two treatments was within the bioequivalence criteria, but for C max the upper bound of the 90 % CI exceeded the standard range for bioequivalence by 7 %. This relatively small change is unlikely to be clinically meaningful. Treatment-emergent adverse events (TEAEs) were reported by 42.9 % of subjects; the most commonly reported TEAEs included dizziness (5.0, 7.3, and 7.3 %) and headache (7.5, 4.9, and 7.3 %) following administration of GXR, LDX, and GXR and LDX in combination, respectively. Clinically significant ECG abnormalities occurred in one subject following administration of LDX and in one subject following coadministration of GXR and LDX.ConclusionsIn healthy adults, coadministration of GXR and LDX did not result in a clinically meaningful pharmacokinetic DDI compared with either treatment alone. No unique TEAEs were observed with coadministration of GXR and LDX compared with either treatment alone.