Pharmacokinetics and pharmacodynamics of ticagrelor in subjects on hemodialysis and subjects with normal renal function.

PURPOSE: This single-dose, randomized, open-label, parallel-group, and crossover study assessed pharmacokinetics (PK), pharmacodynamics (PD), and safety of ticagrelor in subjects on hemodialysis versus healthy subjects. METHODS: Hemodialysis subjects were randomized, receiving a single ticagrelor 90-mg dose 1 day post-hemodialysis or just before hemodialysis, with an intervening washout of ≥ 7 days. Healthy subjects (creatinine clearance ≥ 90 mL/min) received a single ticagrelor 90-mg dose. PK, PD (P2Y12 reaction units [PRU], inhibition of platelet aggregation [IPA]), and safety were evaluated. RESULTS: Twenty-seven subjects (14 hemodialysis, 13 healthy) received ticagrelor. The mean maximum plasma concentration (Cmax) and area under the plasma concentration curve from time zero to infinity (AUC0-∞) of ticagrelor were 598.4 ng/mL and 3256.1 ng·h/mL, respectively, in pre-hemodialysis subjects; 560.3 ng/mL and 3015.1 ng·h/mL, respectively, in post-hemodialysis subjects; and 370.8 ng/mL and 2188.8 ng·h/mL, respectively, in healthy subjects. Cmax and AUC0-∞ of AR-C124910XX, the active metabolite, were 152.3 ng/mL and 1144.2 ng·h/mL, respectively, in pre-hemodialysis subjects; 130.8 ng/mL and 1127.8 ng·h/mL, respectively, in post-hemodialysis subjects; and 111.7 ng/mL and 1000.4 ng·h/mL, respectively, in healthy subjects. Mean IPA time curves over 24 h post-dose were almost indistinguishable for all three treatments. The greatest reduction in mean PRU occurred approximately 2 h post-dose for all three treatments. No safety or tolerability issues were identified. CONCLUSION: Hemodialysis resulted in modestly higher exposure to ticagrelor and AR-C124910XX, with no clinically significant effect on PD or tolerability. Accordingly, no dose adjustment is required for hemodialysis patients. Timing of hemodialysis has little impact on ticagrelor PK, or the effect of ticagrelor on IPA.

Pharmacodynamics, pharmacokinetics, and safety of ticagrelor in Chinese patients with stable coronary artery disease.

AIM: The aim of the study was to assess ticagrelor's effects on inhibition of platelet aggregation (IPA), P2Y12 reaction units (PRU, measure of platelet P2Y12 receptor blockade), pharmacokinetic (PK) parameters and safety in Chinese patients with stable coronary artery disease (CAD). METHODS: This was an open label, single centre, randomized study. Thirty-six patients on low dose aspirin (75-100 mg day(-1) ) received ticagrelor 45, 60 or 90 mg (single dose, days 1 and 7; twice daily, days 3-6). IPA (final extent), PRU and ticagrelor and AR-C124910XX plasma concentrations were determined. RESULTS: On day 1, peak IPA >80% occurred 2-6 h post-dose (all doses). PRU was markedly reduced at 1 h vs. baseline (all doses). With ticagrelor 45 and 90 mg twice daily, maximum IPA (mean, SD) was 91% (13%), and 99% (3%), and maximum PRU reduction from baseline (mean, SD) was 82% (17%) and 92% (9%), respectively. Approximate dose-proportional increases (mean [%CV]; 45 vs. 90 mg twice daily) in ticagrelor Cmax (616 [37] vs. 1273 [43] ng ml(-1) ) and AUC (3882 [42] vs. 8206 [51] ng ml(-1) h) and AR-C124910XX parameters were seen. Pharmacodynamic and PK differences between 45 and 60 mg were small. No safety issues were identified. CONCLUSIONS: In Chinese patients with CAD, ticagrelor (45, 60 and 90 mg) markedly reduced platelet aggregation. The IPA and PRU magnitude increased generally with increasing doses. However, the mean pharmacodynamic differences between 45 and 60 mg doses were small. Following single and multiple doses, the mean Cmax and AUC values of ticagrelor and AR-C124910XX increased approximately dose proportionally between 45 and 90 mg doses.

Population pharmacokinetics of ticagrelor in patients with acute coronary syndromes.

OBJECTIVE: Ticagrelor is an orally administered antiplatelet agent used to reduce thrombotic events in patients with acute coronary syndromes. Data from two studies in patients with acute coronary syndromes with large amounts of pharmacokinetic (PK) data (phase IIb DISPERSE-2 study (n = 609)); phase III PLATO PK substudy (n = 6,381)), along with non-linear mixed effects modeling software, were used to develop population PK models for ticagrelor and its metabolite, AR-C124910XX, and to evaluate the impact of demographic and clinical factors on the PK of ticagrelor and AR-C124910XX. METHODS: 32 covariates relating to disease history, biomarkers, clinical chemistry, and concomitant medications were assessed. RESULTS: A one-compartment model with population mean PK parameters of firstorder absorption rate constant (0.67/h), apparent systemic clearance (14 L/h), and apparent volume of distribution (221 L) was shown to best describe the PK profile of ticagrelor. Patients co-administered moderate CYP3A inducers or inhibitors increased (by 110%, 95% confidence interval (CI), 52 - 192%) or decreased (by 64%, 95% CI, 39 - 73%) apparent ticagrelor clearance, respectively, while habitual smoking decreased apparent ticagrelor clearance by 22% (95% CI, 19 - 25%). Ticagrelor bioavailability was 21% (95% CI, 19 - 22%) lower at treatment initiation (visit 1) versus subsequent visits. Compared with Caucasian patients, ticagrelor bioavailability was 39% (95% CI, 33 - 46%) higher in Asian patients and 18% (95% CI, 6 - 28%) lower in Black patients. CONCLUSIONS: In the current analyses, the population PK models developed for ticagrelor and AR-C124910XX described the data obtained in the DISPERSE-2 and PLATO studies well, and were consistent with previous phase I PK studies.

Effect of genetic variations on ticagrelor plasma levels and clinical outcomes.

AIMS: Ticagrelor, a direct-acting P2Y12-receptor antagonist, is rapidly absorbed and partly metabolized to the major metabolite AR-C124910XX (ARC). To identify single-nucleotide polymorphisms (SNPs) associated with pharmacokinetics of ticagrelor and clinical outcomes, we performed a genome-wide association study (GWAS) in patients treated with ticagrelor in the PLATO trial. METHODS AND RESULTS: A two-stage design was used for the GWAS with discovery (discovery phase: n = 1812) and replication cohorts (replication phase: n = 1941). The steady-state area under the curve (AUCss) values, estimated by the population pharmacokinetic (PK) models, were log transformed and analysed on a genome-wide scale using linear regression. SNPs were analysed against clinical events using Cox-regression in 4990 patients. An SNP (rs113681054) in SLCO1B1 was associated with levels of ticagrelor (P = 1.1 × 10(-6)) and ARC (P = 4.6 × 10(-13)). This SNP is in linkage disequilibrium with a functional variant (rs4149056) that results in decreased OATP1B1 transporter activity. Ticagrelor levels were also associated with two independent SNPs (rs62471956, P = 7.7 × 10(-15) and rs56324128, P = 9.7 × 10(-12)) in the CYP3A4 region. Further, ARC levels were associated with rs61361928 (P = 3.0 × 10(-14)) in UGT2B7. At all loci, the effects were small. None of the identified SNPs that affected ticagrelor PK were associated with the primary composite outcome (cardiovascular death myocardial infarction, and stroke), non-CABG-related bleeds or investigator-reported dyspnoea. CONCLUSION: In patients with ACS, ticagrelor pharmacokinetics is influenced by three genetic loci (SLCO1B1, UGT2B7, and CYP3A4). However, the modest genetic effects on ticagrelor plasma levels did not translate into any detectable effect on efficacy or safety during ticagrelor treatment. CLINICAL TRIAL REGISTRATION: NCT00391872.

A randomised trial of the pharmacodynamic and pharmacokinetic effects of ticagrelor compared with clopidogrel in Hispanic patients with stable coronary artery disease.

The objective was to compare the pharmacodynamic (PD) and pharmacokinetic (PK) effects of ticagrelor with clopidogrel among subjects of Hispanic ethnicity, as the PD and PK effects of antiplatelet agents among Hispanics are not specifically known. This was a randomised, open-label, crossover PD/PK study of 40 Hispanic subjects with stable coronary artery disease (CAD). Subjects were allocated to either ticagrelor 180 mg loading dose (LD)/90 mg twice-daily maintenance dose (MD) followed by clopidogrel 600 mg LD/75 mg once-daily MD with an intervening washout period, or vice versa. The primary endpoint was on-treatment reactivity (OTR) at 2 h post-LD according to the VerifyNow P2Y12 test. OTR was significantly lower at 2 h post-LD with ticagrelor compared with clopidogrel (34 PRU vs. 201 PRU, least square means difference = -167 PRU [95 % CI, -197, -137], P < 0.001). OTR was also lower with ticagrelor at 30 min and 8 h post-LD (P < 0.001). The greater magnitude of antiplatelet effect with ticagrelor persisted after 7 days of MD (52 PRU [95 % CI, 30, 73] vs. 182 PRU [95 % CI, 160, 205], P < 0.001). Mean plasma concentration of ticagrelor and its active metabolite were greatest at 2 h post-LD, with similar levels at 2 h post-MD after 7 days of MD. Among Hispanic subjects with stable CAD, ticagrelor provides a more rapid onset of platelet inhibition and a significantly greater antiplatelet effect compared with clopidogrel during both the loading and maintenance phases of treatment.

An open-label, randomized bioavailability study with alternative methods of administration of crushed ticagrelor tablets in healthy volunteers.

OBJECTIVE: To compare the bioavailability and safety profile of crushed ticagrelor tablets suspended in water and administered orally or via nasogastric tube, with that of whole tablets administered orally. METHODS: In this single-center, open-label, randomized, three-treatment crossover study, 36 healthy volunteers were randomized to receive a single 90-mg dose of ticagrelor administered orally as a whole tablet or as crushed tablets suspended in water and given orally or via a nasogastric tube into the stomach, with a minimum 7-day wash-out between treatments. Plasma concentrations of ticagrelor and AR-C124910XX were assessed at 0, 0.5, 1, 2, 3, 4, 6, 8, 10, 12, 16, 24, 36, and 48 hours post-ticagrelor dose for pharmacokinetic analyses. Safety and tolerability was assessed throughout the study. RESULTS: At 0.5 hours postdose, plasma concentrations of ticagrelor and AR-C124910XX were higher with crushed tablets administered orally (148.6 ng/mL and 13.0 ng/mL, respectively) or via nasogastric tube (264.6 ng/mL and 28.6 ng/mL, respectively) compared with whole-tablet administration (33.3 ng/mL and 5.2 ng/mL, respectively). A similar trend was observed at 1 hour postdose. Ticagrelor tmax was shorter following crushed vs. whole-tablet administration (1 vs. 2 hours, respectively). Geometric mean ratios between treatments for AUC and Cmax were contained within the bioequivalence limits of 80-125% for ticagrelor and AR-C124910XX. All treatments were generally well tolerated. CONCLUSIONS: Ticagrelor administered as a crushed tablet is bioequivalent to whole-tablet administration, independent of mode of administration (oral or via nasogastric tube), and resulted in increased plasma concentrations of ticagrelor and ARC124910XX at early timepoints.

Pharmacokinetics, pharmacodynamics, and tolerability of single and multiple doses of ticagrelor in Japanese and Caucasian volunteers.

OBJECTIVES: Two studies assessing ticagrelor pharmacokinetics, pharmacodynamics, and tolerability in healthy Japanese and Caucasian volunteers. MATERIALS AND METHODS: Single-ascending dose (SAD) study: Japanese (n = 20) and Caucasians (n = 20) received single doses of ticagrelor (50, 100, 200, 300, 400, and 600 mg) or placebo. Multiple-ascending dose (MAD) study: Japanese (n = 36) and Caucasians (n = 36) received single doses of 100 mg or 300 mg ticagrelor (day 1), twice-daily 100 mg or 300 mg ticagrelor, or placebo (days 4 – 9), and single doses of 100 mg or 300 mg ticagrelor (day 10). RESULTS: Exposure to ticagrelor and its active metabolite, AR-C124910XX, was generally higher in Japanese vs. Caucasians. In the SAD study, area under the plasma concentration-time curve (AUC) values were 33% (ticagrelor) and 55% (AR-C124910XX) greater in Japanese vs. Caucasians following 600 mg ticagrelor. In the MAD study, AUC values of ticagrelor and AR-C124910XX following multiple doses of ticagrelor 100 mg and 300 mg were statistically significantly greater (33 - 48%) in Japanese vs. Caucasians. In both groups, mean peak inhibition of platelet aggregation was > 86% after single doses (>= 100 mg ticagrelor) and > 84% after multiple doses. Bleeding times were >= 60 minutes in more Japanese than Caucasians with multiple dosing of 100 mg and 300 mg ticagrelor Adverse events were similar between groups (mild-to-moderate intensity). CONCLUSIONS: The pharmacokinetics and tolerability of ticagrelor were broadly similar in Japanese and Caucasians, although exposure was slightly greater in Japanese volunteers. Ticagrelor was generally well tolerated.

Effect of Hepatic and Renal Impairment on the Pharmacokinetics of Dersimelagon (MT-7117), an Oral Melanocortin-1 Receptor Agonist.

Dersimelagon is an orally administered selective melanocortin-1 receptor agonist being investigated for treatment of erythropoietic protoporphyria, X-linked protoporphyria, and diffuse cutaneous systemic sclerosis. Dersimelagon is extensively metabolized in the liver, and potential recipients may have liver dysfunction. Further, effects of renal impairment on pharmacokinetic properties should be established in drugs intended for chronic use. Two separate studies (ClinicalTrials.gov: NCT04116476; NCT04656795) evaluated the effects of hepatic and renal impairment on dersimelagon pharmacokinetics, safety, and tolerability. Participants with mild (n = 7) or moderate (n = 8) hepatic impairment or normal hepatic function (n = 8) received a single oral 100-mg dersimelagon dose. Participants with mild (n = 8), moderate (n = 8), or severe (n = 8) renal impairment or normal renal function (n = 8) received a single 300-mg dose. Systemic exposure to dersimelagon was comparable with mild hepatic impairment but higher with moderate hepatic impairment (maximum observed plasma concentration, 1.56-fold higher; area under the plasma concentration-time curve from time 0 extrapolated to infinity, 1.70-fold higher) compared with normal hepatic function. Maximum observed plasma concentration and area under the plasma concentration-time curve from time 0 extrapolated to infinity were similar with moderate renal impairment but higher with mild (1.86- and 1.87-fold higher, respectively) and severe (1.17- and 1.45-fold higher, respectively) renal impairment versus normal renal function. Dersimelagon was generally well tolerated.

A pharmacokinetic interaction study of ticagrelor and digoxin in healthy volunteers.

PURPOSE: Ticagrelor is a reversibly binding P2Y12 receptor antagonist for the prevention of atherothrombotic events in patients with acute coronary syndrome. Previous in vitro studies showed that ticagrelor is a substrate and inhibitor of P-glycoprotein (ABCB1). Therefore, we examined the potential interaction between digoxin, a P-glycoprotein substrate, and ticagrelor by evaluating the pharmacokinetics, safety, and tolerability. METHODS: This was a randomized, double-blind, two-period crossover study in healthy volunteers (n = 20). Pharmacokinetic parameters of digoxin and ticagrelor were evaluated following co-administration of ticagrelor 400 mg qd or placebo on days 1-16, and digoxin (0.25 mg bid on day 6 and 0.25 mg qd on days 7-14). RESULTS: Co-administration of ticagrelor increased the digoxin maximum plasma concentration by 75 %, from 1.8 ng/ml to 3.0 ng/ml (Gmean ratio [GMR] 1.75 [95 % CI, 1.52-2.01]); minimum plasma concentration by 31 %, from 0.5 ng/ml to 0.7 ng/ml (GMR 1.31, 1.13-1.52); and mean area under the curve by 28 %, from 16.8 ng · h/ml to 21.0 ng · h/ml (GMR 1.28, 1.12-1.46), compared with placebo. Renal clearance of digoxin was unaffected by the presence of ticagrelor. Digoxin had no effect on the pharmacokinetics of ticagrelor or its active metabolite, AR-C124910XX. Co-administration of ticagrelor and digoxin was well tolerated. CONCLUSIONS: Collectively, these results indicate that ticagrelor is a weak inhibitor of the P-glycoprotein transporter. Based on these findings, it is recommended that serum concentrations of drugs like digoxin (P-glycoprotein transporter substrates with a narrow therapeutic range) are monitored when initiating or changing ticagrelor therapy.

Effect of rifampicin on the pharmacokinetics and pharmacodynamics of ticagrelor in healthy subjects.

PURPOSE: Ticagrelor, a reversibly binding oral P2Y12 receptor antagonist, is predominantly metabolized by cytochrome P450 3A and both the parent compound and its active metabolite AR-C124910XX are substrates of P-glycoprotein. Rifampicin was used to assess the effects of CYP3A and P-glycoprotein induction on the single-dose pharmacokinetics and pharmacodynamics of ticagrelor. METHODS: Healthy volunteers received a single 180 mg oral dose of ticagrelor on days 1 and 15, and a once-daily 600 mg dose of rifampicin on days 4-17. Ticagrelor and AR-C124910XX plasma concentrations were quantified for pharmacokinetic analysis (n = 14); inhibition of platelet aggregation (IPA) was also assessed (n = 14). RESULTS: Compared with administration of ticagrelor alone, co-administration of ticagrelor and rifampicin significantly decreased the maximum plasma concentration (Cmax) of ticagrelor from 1091 to 297.8 ng/ml, area under the plasma concentration-time curve from time zero to infinity (AUC) of ticagrelor from 6225 to 864.0 ng.h/ml, and also decreased plasma half-life of ticagrelor from 8.4 to 2.8 h; reductions of 73 %, 86 % and 67 % respectively. With rifampicin, AR-C124910XX Cmax was unaffected, AUC was significantly decreased by 46 %, and metabolite to parent ratio for AUC increased fourfold. Although maximal IPA was unaffected, offset of ticagrelor-mediated IPA was more rapid in the presence of rifampicin; a significant reduction (27 %) in the area under the effect curve between 0 and 24 h was observed following co-administration with rifampicin. CONCLUSION: Co-administration with rifampicin reduced ticagrelor exposure and resulted in a more rapid offset of ticagrelor-mediated IPA. Co-administration of strong CYP3A/P-glycoprotein inducers with ticagrelor should be discouraged.

Pharmacokinetic interaction studies of co-administration of ticagrelor and atorvastatin or simvastatin in healthy volunteers.

PURPOSE: Interactions between ticagrelor and atorvastatin or simvastatin were investigated in two-way crossover studies. METHODS: Both studies were open-label for statin; the atorvastatin study was placebo-controlled for ticagrelor. For atorvastatin, volunteers (n = 24) received ticagrelor (loading dose 270 mg; 90 mg twice daily, 7 days) or placebo, plus atorvastatin calcium (80 mg; day 5). For simvastatin, volunteers (n = 24) received simvastatin 80 mg, or ticagrelor (loading dose 270 mg; 180 mg twice daily, 7 days) plus simvastatin (80 mg; day 5). In each study, volunteers received the alternate treatment after washout (≥ 7 days). RESULTS: Ticagrelor increased mean atorvastatin maximum plasma concentration (C(max)) and area under the plasma concentration-time curve from zero to infinity (AUC) by 23 % and 36 %, respectively. Simvastatin C(max) and AUC were increased by 81 % and 56 % with ticagrelor. Ticagrelor also increased C(max) and AUC of analysed atorvastatin metabolites by 13-55 % and 32-67 %, respectively, and simvastatin acid by 64 % and 52 %, respectively. Co-administration of ticagrelor with each statin was well tolerated. CONCLUSIONS: Exposure to ticagrelor and its active metabolite, AR-C124910XX, was generally unchanged by a single dose of either statin, except for a minor increase in ticagrelor C(max) in the presence of simvastatin. Effects of ticagrelor on atorvastatin pharmacokinetics were modest and unlikely clinically relevant, while with simvastatin, changes were slightly larger, and simvastatin doses >40 mg with ticagrelor should be avoided.

Evaluation of the pharmacokinetics and pharmacodynamics of ticagrelor co-administered with aspirin in healthy volunteers.

The results of two independent, randomized, two-period crossover, single-center studies, conducted to assess the pharmacokinetics of ticagrelor ± aspirin, inhibition of platelet aggregation (IPA) with ticagrelor/aspirin vs. clopidogrel/aspirin, and safety, tolerability, and bleeding times are reported here. In Study A (open-label), 16 volunteers received ticagrelor (50 mg bid Days 1-5; 200 mg bid Days 6-9; one 200 mg dose on Day 10) ± 300 mg qd aspirin (Days 1-10). In Study B (double-blind, double-dummy), 16 volunteers received aspirin (300 mg loading dose/75 mg qd Days 2-9) with either ticagrelor (200 mg bid Days 4-8, one 200 mg dose on Day 9) or clopidogrel (300 mg loading dose Day 4, 75 mg qd Days 5-9). At steady-state ticagrelor (50 mg bid, or 200 mg bid), concomitant aspirin (300 mg qd) had no effect on mean maximum plasma concentration (Cmax), median time to Cmax (tmax), or mean area under the plasma concentration-time curve for the dosing interval (AUC0-τ) for ticagrelor and its primary metabolite, AR-C124910XX. Following 200 mg bid ticagrelor, mean Cmax and AUC0-τ for both parent and metabolite were comparable with co-administration of aspirin at 75 mg and 300 mg qd. Aspirin (300 mg qd) had no effect on IPA (ADP-induced) by ticagrelor. However, aspirin and ticagrelor had an additive effect on IPA (collagen-induced). Ticagrelor/aspirin increased bleeding times vs. baseline. Ticagrelor/aspirin co-administration was well tolerated at all dose combinations evaluated. In summary, the findings of this study demonstrate that co-administration of aspirin (300 mg qd) with ticagrelor (50 mg bid, or 200 mg bid) had no effect on ticagrelor pharmacokinetics or IPA (ADP-induced) by ticagrelor.

Safety, tolerability, pharmacokinetics and pharmacodynamics of high single-ascending doses of ticagrelor in healthy volunteers.

OBJECTIVE: Previous studies have indicated that ticagrelor is well tolerated and exhibits linear pharmacokinetics up to doses of 600 mg/day. The safety, tolerability, pharmacokinetics and pharmacodynamics (bleeding times and pulmonary function tests) of high single-ascending doses of ticagrelor were assessed to determine the maximum tolerated dose of ticagrelor. MATERIALS AND METHODS: This was a randomized, double-blind, placebo-controlled study. Eight healthy volunteers were planned for enrollment in each of 3 dose groups, ticagrelor 900 mg, 1,260 mg, and 1,620 mg (6 : 2 ratio ticagrelor : placebo). RESULTS: The study stopping criteria were met when 3 of the 6 volunteers receiving ticagrelor 1,260 mg experienced moderate gastrointestinal adverse events (AE); none were observed with placebo. One volunteer receiving ticagrelor 1,260 mg had a serious AE - sinus arrest, high-grade atrioventricular block, and ventricular escape rhythm with syncope - and another volunteer had brief, mild dyspnea. Ticagrelor 900 mg was well tolerated. Total exposure to ticagrelor increased dose proportionally. Peak plasma concentration (Cmax) for ticagrelor did not increase much, most likely due to delayed absorption. There were no relevant changes in respiratory parameters. Bleeding times were prolonged in those receiving ticagrelor with respect to placebo, with longer bleeding times in volunteers receiving ticagrelor 1,260 mg than in volunteers receiving 900 mg; no bleeding events were reported. CONCLUSION: These results indicate that the maximum tolerated single dose of ticagrelor is 900 mg in healthy volunteers.

Evaluation of the pharmacokinetic interaction between ticagrelor and tolbutamide, a cytochrome P450 2C9 substrate, in healthy volunteers.

OBJECTIVES: To assess the effect of ticagrelor on the pharmacokinetics of tolbutamide (a CYP2C9 substrate), and the effect of tolbutamide on ticagrelor pharmacokinetics. METHODS: In this randomized, double-blind, two-period, crossover study, 23 healthy volunteers received either placebo or ticagrelor 180 mg twice daily (b.i.d.) for 9 days, with a single open-label oral dose of tolbutamide 500 mg on Day 5. After washout (14 days), volunteers received the alternate treatment. Plasma concentrations of tolbutamide, 4-hydroxytolbutamide, ticagrelor, and AR-C124910XX were determined for pharmacokinetic analyses. RESULTS: Ticagrelor had no effect on tolbutamide or 4-hydroxytolbutamide pharmacokinetic parameters. The geometric least square mean ratios for maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from Time 0 to infinity (AUC0-∞) were lose to unity, and the 90% confidence intervals (CI) were within the range 0.80 - 1.25 for both tolbutamide and 4-hydroxytolbutamide. The terminal elimination half-life (t1/2), and time to maximal plasma concentrations (tmax) for tolbutamide and its metabolite were unaffected by ticagrelor coadministration. Tolbutamide had no effect on the Cmax, area under the concentration curve over the 2-hour dosing interval (AUC0-τ), t1/2 or tmax of either ticagrelor or AR-C124910XX. Coadministration of ticagrelor and tolbutamide was well tolerated. CONCLUSIONS: These results suggest that ticagrelor does not affect tolbutamide metabolism and is therefore unlikely to affect CYP2C9-mediated metabolism of drugs.

The Oral Bioavailability and Effect of Various Gastric Conditions on the Pharmacokinetics of Dersimelagon in Healthy Adult Volunteers.

Dersimelagon is a novel orally administered selective agonist for melanocortin receptor 1 being investigated for the treatment of erythropoietic protoporphyria, X-linked protoporphyria, and diffuse cutaneous systemic sclerosis. In this open-label, multicenter, randomized, two-cohort, sequential crossover study, the relative oral bioavailability of two tablet formulations of dersimelagon was evaluated, and the effect of various gastric conditions (from a high-fat meal, a proton-pump inhibitor, and an acidic carbonated beverage) on the pharmacokinetics of dersimelagon were assessed in healthy participants (N = 50). Both tablet formulations demonstrated rapid absorption, and the 100-mg tablets showed a 97% relative oral bioavailability versus 50-mg tablets. No effect was observed on overall exposure (area under the plasma concentration versus time curve [AUC]) following consumption of a high-fat meal, and Cmax was higher (22%, 90% confidence interval [CI] 1.05-1.42) in a fed state compared with fasted conditions. Similarly, overall exposure AUC of dersimelagon was comparable following administration alone or in combination with esomeprazole; however, coadministration of esomeprazole led to a slight decrease in Cmax (fasted: 9%, 90%CI 0.77-1.07; fed: 24%, 90%CI 0.66-0.88) compared with administration of dersimelagon alone. In general, the consumption of an acidic beverage increased time to Cmax regardless of fed or fasted status and decreased overall exposure AUC and Cmax of dersimelagon.

Effect of age and gender on pharmacokinetics and pharmacodynamics of a single ticagrelor dose in healthy individuals.

PURPOSE: The aim of this study was to assess age and gender effects on ticagrelor pharmacokinetics and pharmacodynamics (PK/PD). METHODS: Forty healthy individuals [18-45 years (young); ≥ 65 years (elderly); ten men, ten women per age group) received 200 mg ticagrelor. RESULTS: Ticagrelor was rapidly absorbed [time to maximum concentration (C(max)) (t(max)) 2.5-3.0 h], and its major active metabolite, AR-C124910XX rapidly formed (t(max) 3.0-3.5 h) in all groups. Ticagrelor exposure was higher in elderly vs. the young [area under the curve from time 0 to infinity (AUC(0-∞)) 52%; C(max) 63% higher] and women vs. men (AUC(0-∞) 37%; C(max) 52% higher). Mean terminal elimination half-life was slightly longer in women vs. men but was unaffected by age. Similar results were observed for AR-C124910XX (elderly vs. young, AUC(0-∞) 48%; C(max) 61% higher), and in women vs. men (AUC(0-∞) 55%; C(max) 56% higher). Across all groups, ticagrelor produced substantial final-extent inhibition of platelet aggregation (IPA): >90% at 4 and 8 h postdose. Individuals with highest ticagrelor exposure (i.e., elderly) had the lowest IPA, indicating an age-related platelet sensitivity effect. In young individuals, platelet sensitivity was greater in men vs. women. Ticagrelor tolerability was not affected by age or gender. CONCLUSIONS: Systemic exposures to ticagrelor and AR-C124910XX were higher in elderly vs. young and in women vs. men. Age- and gender-related changes in IPA were apparent, but substantial IPA was achieved in all groups. No adjustment in ticagrelor dose should be considered necessary based on age and gender.

Response to ticagrelor in clopidogrel nonresponders and responders and effect of switching therapies: the RESPOND study.

BACKGROUND: The antiplatelet effects of the Platelet Inhibition and Patient Outcomes (PLATO) trial dose of ticagrelor in patients nonresponsive to clopidogrel and after they switch agents are unknown. METHODS AND RESULTS: Patients with stable coronary artery disease on aspirin therapy received a 300-mg clopidogrel load; nonresponders were identified by light transmittance aggregometry. In a 2-way crossover design, nonresponders (n=41) and responders (n=57) randomly received clopidogrel (600 mg/75 mg once daily) or ticagrelor (180 mg/90 mg twice daily) for 14 days during period 1. In period 2, all nonresponders switched treatment; half of the responders continued the same treatment, whereas the others switched treatment. Inhibition of platelet aggregation was higher in nonresponders treated with ticagrelor compared with clopidogrel (P<0.05). Treatment with ticagrelor among nonresponders resulted in a >10%, >30%, and >50% decrease in platelet aggregation from baseline in 100%, 75%, and 13% of patients, respectively. Platelet aggregation fell from 59+/-9% to 35+/-11% in patients switched from clopidogrel to ticagrelor and increased from 36+/-14% to 56+/-9% in patients switched from ticagrelor to clopidogrel (P<0.0001 for both). Platelet reactivity was below the cut points previously associated with ischemic risk measured by light transmittance aggregometry, VerifyNow P2Y(12) assay, and vasodilator-stimulated phosphoprotein phosphorylation in 98% to 100% of patients after ticagrelor therapy versus 44% to 76% of patients after clopidogrel therapy. CONCLUSIONS: Ticagrelor therapy overcomes nonresponsiveness to clopidogrel, and its antiplatelet effect is the same in responders and nonresponders. Nearly all clopidogrel nonresponders and responders treated with ticagrelor will have platelet reactivity below the cut points associated with ischemic risk. Clinical Trial Registration- http://www.clinicaltrials.gov. Unique Identifier: NCT00642811.

Randomized double-blind assessment of the ONSET and OFFSET of the antiplatelet effects of ticagrelor versus clopidogrel in patients with stable coronary artery disease: the ONSET/OFFSET study.

BACKGROUND: Ticagrelor is the first reversibly binding oral P2Y(12) receptor antagonist. This is the first study to compare the onset and offset of platelet inhibition (IPA) with ticagrelor using the PLATO (PLATelet inhibition and patient Outcomes) trial loading dose (180 mg) with a high loading dose (600 mg) of clopidogrel. METHODS AND RESULTS: In a multicenter, randomized, double-blind study, 123 patients with stable coronary artery disease who were taking aspirin therapy (75 to 100 mg/d) received ticagrelor (180-mg load, 90-mg BID maintenance dose [n=57]), clopidogrel (600-mg load, 75-mg/d maintenance dose [n=54]), or placebo (n=12) for 6 weeks. Greater IPA (20 micromol/L ADP, final extent) occurred with ticagrelor than with clopidogrel at 0.5, 1, 2, 4, 8, and 24 hours after loading and at 6 weeks (P<0.0001 for all); by 2 hours after loading, a greater proportion of patients achieved >50% IPA (98% versus 31%, P<0.0001) and >70% IPA (90% versus 16%, P<0.0001) in the ticagrelor group than in the clopidogrel group, respectively. A faster offset occurred with ticagrelor than with clopidogrel (4-to-72-hour slope [% IPA/h] -1.04 versus -0.48, P<0.0001). At 24 hours after the last dose, mean IPA was 58% for ticagrelor versus 52% for clopidogrel (P=NS). IPA for ticagrelor on day 3 after the last dose was comparable to clopidogrel at day 5; IPA on day 5 for ticagrelor was similar to clopidogrel on day 7 and did not differ from placebo (P=NS). CONCLUSIONS: Ticagrelor achieved more rapid and greater platelet inhibition than high-loading-dose clopidogrel; this was sustained during the maintenance phase and was faster in offset after drug discontinuation.

Absorption, distribution, metabolism, and excretion of ticagrelor in healthy subjects.

Ticagrelor [(1S,2S,3R,5S)-3-[7-[[(1R,2S)-2-(3,4-difluorophenyl) cyclopropyl]amino]-5-(propylthio)-3H-1,2,3-triazolo[4,5-d]pyrimidin-3-yl]-5-(2-hydroxyethoxy)-1,2-cyclopentanediol)] is a reversibly binding oral P2Y(12) receptor antagonist in development for the prevention of thrombotic events in patients with acute coronary syndromes. The pharmacokinetics, metabolism, and excretion of ticagrelor were investigated over 168 h in six healthy male subjects receiving a single oral suspension dose of 200 mg of [(14)C]ticagrelor. Ticagrelor was rapidly absorbed with a maximum plasma concentration at 1.5 h. The major active metabolite, AR-C124910XX, is formed by O-deethylation. Exposure to AR-C124910XX was 29% of peak and 40% of overall exposure to ticagrelor. In most subjects, radioactivity was undetectable in plasma after 20 h and whole blood after 12 h (half-life values of 6.3 and 4.6 h, respectively). The ratio of radioactivity in plasma to whole blood was 1.69, suggesting that ticagrelor and its metabolites are largely restricted to the plasma space. Mean radioactivity recovery was 26.5% in urine and 57.8% in feces. Major circulating components in the plasma and feces were identified as ticagrelor and AR-C124910XX, whereas in urine the major components were metabolite M5 (AR-C133913XX) and its glucuronide conjugate M4. Levels of unchanged ticagrelor and AR-C124910XX were <0.05% in the urine, indicating that renal clearance of ticagrelor and AR-C124910XX is of minor importance. Interindividual variability was small in both urine and fecal extracts with only small quantitative differences. All 10 of the metabolites were fully or partially characterized and a full biotransformation pathway was proposed for ticagrelor, in which oxidative loss of the hydroxyethyl side chain from ticagrelor forms AR-C124910XX and a second oxidative pathway leads to N-dealkylation of ticagrelor, forming AR-C133913XX.

Pharmacokinetics, pharmacodynamics, safety and tolerability of multiple ascending doses of ticagrelor in healthy volunteers.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: The antiplatelet agent clopidogrel is currently the recommended treatment for acute coronary syndrome (ACS). Inhibition of platelet aggregation (IPA) with clopidogrel is insufficient, which increases the risk for recurrent ischaemic events. Therefore, there is a need for antiplatelet agents with improved IPA. Ticagrelor (AZD6140) is a new antiplatelet agent in clinical development for reduction of thrombotic events in patients with ACS. WHAT THIS STUDY ADDS: This study assesses the optimal dosing schedule for ticagrelor in healthy volunteers and compares the degree of IPA with clopidogrel. Our findings illustrate that the pharmacokinetics of ticagrelor are predictable and are associated with consistent inhibition of platelet activity. IPA with ticagrelor was greater and better sustained at high levels with twice daily ticagrelor than once daily regimens. AIM: To determine the pharmacokinetics, pharmacodynamics, safety and tolerability of multiple oral doses of ticagrelor, a P2Y(12) receptor antagonist, in healthy volunteers. METHODS: This was a randomized, single-blind, placebo-controlled, ascending dose study. Thirty-two subjects received ticagrelor 50-600 mg once daily or 50-300 mg twice daily or placebo for 5 days at three dose levels in two parallel groups. Another group of 16 subjects received a clopidogrel 300 mg loading dose then 75 mg day(-1), or placebo for 14 days. RESULTS: Ticagrelor was absorbed with median t(max) 1.5-3 h, exhibiting predictable pharmacokinetics over the 50-600 mg dose range. Mean C(max) and AUC for ticagrelor and its main metabolite, AR-C124910XX, increased approximately dose-proportionately (approximately 2.2- to 2.4-fold with a twofold dose increase) over the dose range. Inhibition of platelet aggregation (IPA) with ticagrelor was greater and better sustained at high levels with ticagrelor twice daily vs. once daily regimens. Throughout dosing, more consistent IPA was observed at doses > or = 300 mg once daily and > or = 100 mg twice daily compared with clopidogrel. Mean IPA with ticagrelor > or = 100 mg twice daily was greater and less variable (93-100%, range 65-100%) than with clopidogrel (77%, range 11-100%) at trough concentrations. No safety or tolerability issues were identified. CONCLUSIONS: Multiple dosing provided predictable pharmacokinetics of ticagrelor and its metabolite over the dose range of 50-600 mg once daily and 50-300 mg twice daily with C(max) and AUC(0,t) increasing approximately dose-proportionally. Greater and more consistent IPA with ticagrelor at doses > or = 100 mg twice daily and > or = 300 mg once daily were observed than with clopidogrel. Ticagrelor at doses up to 600 mg day(-1) was well tolerated.