CS-8635, a fixed-dose triple combination of olmesartan, amlodipine, and hydrochlorothiazide, was developed to address the growing need for additional blood pressure (BP) reduction in patients not controlled with dual-combination therapies. Prior to Phase III, modeling and simulation (M&S) was conducted to estimate the additional BP lowering effect of CS-8635 compared to the respective dual combinations. The Phase III study evaluated CS-8635 BP lowering effects only at the highest dose strength among the five dose strengths to be developed. Post-trial M&S was performed using an integrated dataset from three Phase III programs; CS-8635 plus two prior dual combinations. M&S robustly estimated and described the BP lowering effects of CS-8635 evaluated in a clinical setting. Furthermore, M&S evaluated BP lowering effects of the additional four dose strengths not studied. In summary, M&S aided the development of the clinical study and full characterization of the BP lowering effects of CS-8635 across intermediate doses.

SummaryEdoxaban is a novel, orally available, highly specific direct inhibitor of factor Xa and is currently being developed for the treatment and prevention of venous thromboembolism and prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation (NVAF). The objectives of the present analyses were to characterise edoxaban population pharmacokinetics (PPK) and identify potential intrinsic and extrinsic factors affecting variability in edoxaban exposure, determine if there are relationships between edoxaban pharmacokinetics or biomarkers and the risk of bleeding in patients with NVAF using an exposure-response model, and to use the PPK and exposure-response model to support dose selection for a phase III trial of edoxaban in patients with NVAF. PPK analysis of data from 1,281 edoxaban-dosed subjects with intrinsic factors such as renal impairment or NVAF and extrinsic factors such as concomitant medications revealed significant effects of renal impairment and concomitant strong P-glycoprotein (P-gp) inhibitors on the pharmacokinetics of edoxaban. Exposure-response analysis found that in patients with NVAF, the incidence of bleeding events increased significantly with increasing edoxaban exposure, with steady-state minimum concentration (Cmin,ss) showing the strongest association. Clinical trial simulations of bleeding incidence were used to select 30 mg and 60 mg once-daily edoxaban with 50% dose reductions for patients with moderate renal impairment or receiving concomitant strong P-gp inhibitors as the treatment regimens in the ENGAGE AF-TIMI 48 (NCT00781391) trial.The results of this study were previously presented at the 2009 International Society on Thrombosis and Haemostasis, July 2009, Boston, Massachusetts, USA.

Modeling and simulation were used extensively in the development of an indication for the use of olmesartan medoxomil in pediatric patients with hypertension. Simulations based on models developed in adult patients indicated that two dose groups were sufficient to estimate a dose-response relationship, thereby reducing by one-third the number of subjects required for the phase III pediatric study. Model-based predictions for blood pressure reduction agreed with the observed results of the subsequent phase III study, showing statistically significant dose-response relationships with respect to both systolic and diastolic blood pressure. Previously established pharmacokinetic and exposure-response relationships in adults, adjusted for the influence of body weight on clearance (wt(0.80)), were confirmed in the pediatric population. Together, these findings support an olmesartan dosing recommendation in pediatric subjects aged 6 to 16 years of 10 mg for subjects weighing <35 kg and 20 mg for those weighing >= 35 kg.

Background: The prevalence and importance of hypertension in younger patients is becoming increasingly recognized; however, only a limited number of clinical trials have been conducted in the pediatric population.

SummaryEdoxaban is an oral direct factor Xa inhibitor approved for the prevention of venous thromboembolism (VTE) in Japan. The objectives of this analysis were to characterise the population pharmacokinetics (PK) of edoxaban and the relationships between edoxaban exposure and clinical outcomes in a phase IIb study of surgical patients following total hip replacement (THR). A total of 1,795 subjects from a phase IIb study, 10 phase I studies, and three phase IIa studies were included in the PK analysis. The exposure-response analysis included data from surgical patients assigned to edoxaban in the phase IIb study. Edoxaban disposition in healthy and post-surgical patients was well-described with a linear, two-compartment model. Creatinine clearance was significantly correlated with edoxaban clearance and the rate of oral absorption was affected by surgery. The probability of a post-operative VTE was significantly correlated with steady-state metrics of edoxaban exposure estimated for each subject by Bayesian post-hoc methods with age and gender being the significant and expected covariates. The incidence of bleeding was low in these studies and hence no exposure-response relationship could be identified. These analyses suggest that edoxaban has a predictable anticoagulant effect in this patient population leading to dose-proportional reduction in incidence of VTE with low incidence of bleeding.

In TRITON-TIMI 38, levels of the prasugrel active metabolite (pras-AM) were measured in a population pharmacokinetic substudy that characterized the intrinsic and extrinsic factors influencing exposure. Higher exposure to the pras-AM was observed in low-weight or very elderly patients. The authors hypothesized that this higher exposure might explain the higher risk of non-coronary artery bypass graft (CABG)-related TIMI-related bleeding observed in these 2 patient populations. The relationship between estimated exposure to the pras-AM and clinical outcomes was assessed in 1159 prasugrel-treated patients enrolled in the substudy using multivariable logistic regression analysis. There was no relationship between pras-AM exposure and efficacy through 3 days or after 3 days. Higher estimated pras-AM exposure was associated with a higher incidence of non-CABG-related TIMI major or minor bleeding after 3 days (P < .05) but not through 3 days from start of study drug. Factors associated with increased risk for non-CABG-related TIMI bleeding (≥75 years and <60 kg) also identified subgroups with higher exposure to the pras-AM. Within low body weight and very elderly subgroups, bleeding was largely confined to patients having the highest exposure to the pras-AM, indicating that a prasugrel lower dose in these subgroups may reduce the risk of bleeding while maintaining efficacy.

PURPOSE:Prasugrel is a novel thienopyridine prodrug metabolised to an active metabolite that binds irreversibly to the platelet P2Y(12) receptor and inhibits adenosine diphosphate (ADP)-induced platelet aggregation. We compared prasugrel pharmacokinetics, pharmacodynamics, and tolerability in healthy Chinese, Japanese, Korean and Caucasian subjects.METHODS:In an open-label, single-centre, parallel-design study, 89 healthy subjects (25 Chinese, 20 Japanese, 22 Korean and 22 Caucasian) aged 20-65 years were given a prasugrel 60-mg loading dose (LD) followed by daily 10-mg maintenance doses (MD) for 7 days and then 5-mg MD for 10 days. Plasma concentrations of prasugrel's active metabolite and inhibition of ADP-induced platelet aggregation (IPA) were determined.RESULTS:Mean exposure to prasugrel's active metabolite in all treatment regimens was higher in each of the Asian groups than in the Caucasian group, although there was considerable overlap between individual exposure estimates in Asians and Caucasians. The mean IPA was also higher in Asians than in Caucasians following a prasugrel 60-mg LD, although the difference did not consistently achieve statistical significance. Prasugrel 10-mg or 5-mg MD produced statistically significantly higher IPA in each Asian group compared with that in the Caucasians. Prasugrel was well tolerated during the LD and MD regimens by all groups.CONCLUSIONS:Mean exposure to the prasugrel active metabolite following prasugrel 60-mg LD and during daily 10-mg or 5-mg MD was higher in each of the Asian groups than in the Caucasian group, which resulted in greater platelet inhibition.

Thienopyridines are inactive prodrugs that are converted in vivo to active metabolites, which irreversibly bind to and inactivate platelet P2Y(12) receptors, and inhibit platelet activation and aggregation. Prasugrel is a third-generation thienopyridine, recently approved for prevention of thrombotic cardiovascular complications in patients with an acute coronary syndrome undergoing percutaneous coronary intervention. Prasugrel is converted to its active metabolite (Pras-AM; compound R-138727) in two sequential steps: (i) rapid and complete hydrolysis by intestinal human carboxylesterase-2 to form a thiolactone intermediate; and (ii) oxidation of the thiolactone by cytochrome P450 (CYP) enzymes in the gut and/or the liver. CYP3A and CYP2B6 are the primary CYPs contributing to Pras-AM formation, with smaller contributions from CYP2C9 and CYP2C19. Prasugrel is rapidly absorbed and metabolized, with Pras-AM plasma concentrations peaking at about 0.5 hours after oral administration; this helps to account for the rapid onset of inhibition of platelet aggregation (IPA) achieved by prasugrel. In the clinical pharmacology programme for prasugrel, bodyweight had the greatest effect of all covariates that were tested. In the phase III TRITON-TIMI 38 trial, the mean exposure to Pras-AM was 42% greater in patients weighing < 60 kg than in patients with the study population median bodyweight of 85 kg. In a pharmacodynamic meta-analysis of data from healthy subjects a decrease of 1 kg in bodyweight was associated with an increase in IPA of approximately 0.26 percentage points (p < 0.0001). Pras-AM exposure was greater in subjects aged ≥ 75 years, but exposure differences were not as large as those for bodyweight. Pras-AM exposure was greater in Asians than in Caucasians, but this appeared to result from a disproportionately greater exposure difference in Asian subjects with low bodyweight. Sex and allelic variation in CYPs 1A2, 2B6, 2C19, 2C9, 3A4 and 3A5 appeared to have no clinically relevant effect on Pras-AM exposure or IPA. Consistent with the lack of association between genetic status and these pharmacokinetic and pharmacodynamic results in healthy subjects, no significant association was detected between these allelic variants and the composite primary endpoint (cardiovascular death, non-fatal myocardial infarction or non-fatal stroke) in the TRITON-TIMI 38 trial. Studies in renally impaired subjects and subjects with mild or moderate hepatic impairment have indicated that dose adjustment is not required in these patient populations. Prasugrel has few clinically significant drug-drug interactions. Potent CYP3A inhibitors, gastric acid suppressants and food have been shown to reduce the rate of formation of Pras-AM but not its overall exposure. This pharmacokinetic effect reduced the rate of onset of IPA after a loading dose but did not affect the peak IPA after a loading dose or the IPA during maintenance dosing. Potent induction of CYP3A, as well as smoking--which induces CYP1A2--did not affect Pras-AM exposure or IPA. Prior treatment with clopidogrel did not influence tolerability to prasugrel and did not appear to alter IPA during prasugrel treatment. Prasugrel did not affect the activities of CYP2C9, CYP2C19 or P-glycoprotein, but it weakly inhibited CYP2B6. The inhibition of CYP2B6 is potentially clinically significant only for drugs that have a narrow therapeutic window and have CYP2B6 as the primary elimination pathway. No interaction was detected between prasugrel and heparin. Although prasugrel did not alter warfarin pharmacokinetics, prasugrel and warfarin should not be used together, because of an increased bleeding risk associated with their concomitant use.

Inhibition of platelet aggregation (IPA) has been a drug development target in acute coronary syndrome (ACS) for almost 2 decades. The relationship between IPA and cardiovascular (CV) events has not been quantified. Cardiovascular (non fatal myocardial infarction, death) and major bleeding events were extracted from phase 2 or 3 randomized, double‐blind trials that evaluated oral and intravenous glycoprotein 2b/3a (GP2b/3a) antagonists and thienopyridines. IPA was extracted from different sources that studied a similar regimen in a similar population. Events were correlated to IPA using a linear relative‐risk mixed‐effects model. Covariates included type of drug, mean age, gender percentage, and ADP. Clinical trial simulations were conducted to evaluate the relationship between IPA and the likelihood of observing a CV event in a 6‐month end point trial. Data from 81918 subjects in 20 studies were extracted from the literature. To achieve a 20% relative reduction in CV events would require a further 77% (56%‐100%) absolute increase in IPA for IV GP2b/3a antagonists or a further 27%(20%‐41%) absolute increase for thienopyridines. CV risk reduction was less in studies with older subjects and greater in studies with greater percentages of male subjects. Assuming a 3% major bleeding rate in the control group, these drugs had a 1% increase in absolute risk as absolute platelet inhibition increases by 60% (range, 40%‐80%). This relationship in intrinsic bleeding may be different in different population subtypes. Assuming a 12% event rate, a 6‐month active‐controlled thienopyridine trial with 3000 subjects could detect a relationship between CV events and IPA with 80% likelihood. Target IPA increases in ACS are an absolute increase of 80% for IV GP2b/3a antagonists and 30% for thienopyridines. Quantitative models using literature data on IPA and CV events can be used to select dose regimens in early stages of drug development.

BACKGROUND:Prasugrel is an oral antiplatelet agent approved for the reduction of atherothrombotic cardiovascular events in patients presenting with acute coronary syndrome and undergoing percutaneous coronary intervention. Although the approved loading dose is 60 mg, earlier studies of prasugrel suggested that active-metabolite exposure and pharmacodynamic response may be higher in Asian subjects than in white subjects. OBJECTIVES:This study compared the pharmacodynamic response to a single 30-mg dose of prasugrel in healthy Chinese and white subjects and the response to a single 30-mg dose of prasugrel and a single 300-mg dose of clopidogrel in healthy Chinese subjects. The pharmacokinetics and tolerability of both drugs were also assessed. METHODS:This was an open-label, single-dose study conducted in Singapore. Chinese subjects were randomly allocated to receive prasugrel 30 mg or clopidogrel 300 mg; after a 14-day washout period, they received the alternative drug. White subjects received only prasugrel 30 mg. Blood samples for pharmaco-dynamic assessments were collected before dosing and at 0.5, 1, 2, 4, and 24 hours after dosing. Three methods were used to measure inhibition of platelet aggregation (IPA)-traditional light transmission aggregometry (LTA), the Verify Now P2Y12 (VN-P2Y12) assay, and a vasodilator-stimulated phosphoprotein (VASP) phosphorylation flow cytometry assay-and their results were compared. Blood samples for pharmacokinetic assessments were collected at 0.25, 0.5, 1, 1.5, 2, 4, 8, 12, and 24 hours after dosing. Concentrations of the active metabolite of prasugrel were measured using a validated LC-MS/MS method. RESULTS:The study enrolled 18 Chinese subjects and 14 white subjects. Chinese subjects had a mean (SD) age of 31 (10) years and a mean body weight of 65.2 (8.9) kg; 83% were male. The corresponding values for white subjects were 30 (10) years, 77.2 (12.4) kg, and 86%. Thirty of the 32 enrolled subjects completed the study. Two Chinese men were withdrawn from the study, one due to a low platelet-rich plasma count after receipt of prasugrel 30 mg and the other due to mild, intermittent rectal bleeding after bowel movements that began approximately 2 days after receipt of clopidogrel 300 mg. The mean IPA with prasugrel was significantly higher in Chinese than in white subjects at 0.5, 1, and 2 hours after dosing (P < 0.05), but not at 4 or 24 hours. In Chinese subjects, mean maximal IPA (87%) occurred 1 hour after prasugrel dosing; in white subjects, mean maximal IPA (78%) occurred 2 hours after prasugrel dosing. In Chinese subjects, the mean IPA was significantly higher at all time points after administration of prasugrel 30 mg than after administration of clopidogrel 300 mg (P <0.001). After administration of Clopidogrel 300 mg in Chinese subjects, mean maximal IPA (58%) occurred at 4 hours. The VN-P2Y12 and VASP phosphorylation assays yielded results comparable to those obtained by LTA. Mean exposure to prasugrel's active metabolite was higher in Chinese than in white subjects (geometric least squares mean ratio for AUC(0-t) = 1.47 (90% CI, 1.24-1.73). Both drugs were well tolerated. CONCLUSIONS:In this study, platelet inhibition was significantly higher in Chinese than in white subjects up to 2 hours after a single 30-mg dose of prasugrel. Platelet inhibition was significantly higher in Chinese subjects at all time points after a 30-mg dose of prasugrel than after a 300-mg dose of clopidogrel. Both treatments were generally well tolerated.

BACKGROUND:A substantial portion of patients at risk for acute coronary syndrome (ACS) are >65 years old. Prasugrel is a novel antiplatelet agent approved for the treatment of ACS patients undergoing percutaneous coronary intervention, and will be used in this population. OBJECTIVE:This study assessed the effect of age >or=65 years on the pharmacokinetics (PK) and pharmacodynamics (PD) of the active metabolite (R-138727) of prasugrel in healthy subjects taking aspirin (acetylsalicylic acid). METHODS:This was an open-label, single-sequence trial conducted in a single clinical research centre in the UK. A total of 17 subjects aged 65-80 years and 15 subjects aged 20-39 years received a prasugrel 5-mg once-daily maintenance dose for 10 days followed by 10-mg once daily maintenance doses for 10 days. All subjects also received aspirin 75 mg daily. Serial blood samples were collected pre-dose and at various times post-dose for measurement of the active metabolite of prasugrel in plasma on days 10 and 20, following the last 5- and 10-mg prasugrel dose, respectively. PK parameters of the active metabolite of prasugrel included area under the plasma concentration-time curve (AUC) from time zero to the time of the last quantifiable concentration (AUC(last)), maximum plasma concentration (C(max)) and time to C(max) (t(max)). Maximal platelet aggregation (MPA), assessed by light transmission aggregometry using adenosine diphosphate (ADP) 20 micromol/L, was assessed at baseline and on day 10 (5-mg maintenance dose) and day 20 (10-mg maintenance dose). Bleeding times (BTs) were determined on days -5, 1, 10, 11, 20 and 21 using a modified Ivy technique. RESULTS:AUC(last) did not differ significantly between age groups. The steady-state trough MPA to ADP 20 micromol/L during 10-mg maintenance dosing was 30.6% and 26.6% in elderly and young subjects, respectively. Mean MPA was consistently higher in elderly subjects compared with young subjects; however, differences were generally less than ten percentage points. BTs did not differ between the two populations during 5-mg maintenance dosing; however, during 10-mg maintenance dosing, BTs were up to 67% longer in young compared with elderly subjects. A higher frequency of minor bleeding during 10-mg maintenance dosing was observed in elderly subjects compared with young subjects. CONCLUSIONS:These data indicate that prasugrel PK and MPA were similar in healthy subjects regardless of age. Compared with younger subjects, elderly subjects had shorter BTs but a greater frequency of mild bleeding-related adverse events.

A substantial portion of patients at risk for acute coronary syndrome (ACS) are >65 years old. Prasugrel is a novel antiplatelet agent approved for the treatment of ACS patients undergoing percutaneous coronary intervention, and will be used in this population.

Serial pharmacokinetic (PK) sampling in 1159 patients from TRITON-TIMI 38 was undertaken. A multilinear regression model was used to quantitatively predict prasugrel's active metabolite (Pras-AM) concentrations from its 2 downstream inactive metabolites. Population-based methods were then applied to Pras-AM concentration data to characterize the PK. The potential influence of body weight, body mass index, age, sex, renal function, diabetes, tobacco use, and other disease status on Bayesian estimates of Pras-AM exposures was assessed. The PK of Pras-AM was adequately described by a multicompartmental model and consistent with results from previous studies. The systemic exposure of prasugrel was not appreciably affected by body mass index, gender, diabetes, smoking, and renal impairment. Pras-AM mean exposure in patients weighing <60 kg (4.1%) was 30% (90% confidence interval [CI] 1.16-1.45) higher than exposure in patients > or =60 kg. Mean Pras-AM exposures for patients > or =75 years (10.5%) were 19% (90% CI: 1.11-1.28) higher compared with patients <75 years.

OBJECTIVES:This study evaluated flexible-dose pharmacokinetics, safety, and effectiveness of aripiprazole in children and adolescents with conduct disorder (CD). METHODS:This open-label, 15-day, three-center study with an optional 36-month extension enrolled a total of 23 patients: 12 children (6-12 years) and 11 adolescents (13-17 years) with CD and a score of 2-3 on the Rating of Aggression Against People and/or Property (RAAPP). Initially, the protocol used the following dosing: subjects <25 kg, 2 mg/day; subjects 25-50 kg, 5 mg/day; subjects >50-70 kg, 10 mg/day; and subjects >70 kg, 15 mg/day. Due to vomiting and sedation, this schedule was revised to: <25 kg, 1 mg/day; 25-50 kg, 2 mg/day; >50-70 kg, 5 mg/day; and >70 kg, 10 mg/day. RESULTS:Aripiprazole pharmacokinetics were linear, and steady state appeared to be attained within 14 days. Both groups demonstrated improvements in RAAPP scores and Clinical Global Impressions-Severity (CGI-S) scores. Adverse events were similar to the known profile for aripiprazole in adults. CONCLUSION:The pharmacokinetics of aripiprazole in children and adolescents are linear and comparable with those in adults. Aripiprazole was generally well-tolerated in patients with CD, particularly after protocol adjustments, with improvements in aggressive behavior.

Quantitative structure-property relationship (QSPR) models were developed to correlate physicochemical properties of structurally unrelated drugs with extent of in vitro binding to colesevelam, and predicted values were compared with drug exposure changes in vivo following coadministration. The binding of 17 drugs to colesevelam was determined by an in vitro dissolution drug-binding assay. Data from several clinical studies in healthy volunteers to support administration of colesevelam in diabetic patients were also collected along with existing in vivo literature data and compared with in vitro results. Steric, electronic, and hydrophobic descriptors were calculated for test compounds, and univariate and partial least squares regression approaches were used to derive QSPR models to evaluate which of the molecular descriptors correlated best with in vitro binding. A quadrant analysis evaluated the correlation between predicted/actual in vitro binding results and the in vivo data. The in vitro binding assay exhibited high sensitivity, identifying those compounds with a low probability of producing relevant in vivo drug interactions. Drug lipophilicity was identified as the primary determinant of in vitro binding to colesevelam by the final univariate and partial least squares models (R-2 = 0.69 and 0.98; Q(2) = 0.48 and 0.59). The in vitro assay and in silico models represent predictive tools that may allow investigators to conduct only informative clinical drug interaction studies with colesevelam.

The purpose of this study was to assess effects of colesevelam on the pharmacokinetics of glyburide, levothyroxine, estrogen estradiol (EE), norethindrone (NET), pioglitazone, and repaglinide in healthy volunteers. Six drugs with a potential to interact with colesevelam were studied in open-label, randomized clinical studies. The presence of a drug interaction was concluded if the 90% confidence intervals for the geometric least squares mean ratios of AUC(0-t) (AUC(0-48) for levothyroxine) and C(max) fell outside the no-effect limits of (80.0%, 125.0%). Concomitant administration of colesevelam had no effect on the AUC(0-t) or C(max) of pioglitazone but significantly decreased the AUC(0-t) and C(max) of glyburide, levothyroxine, and EE and the C(max) of repaglinide and NET. AUC(0-t) and C(max) of glyburide and EE, but not repaglinide or NET, were significantly decreased when the drug was given 1 hour before colesevelam. When glyburide, EE, or levothyroxine was given 4 hours before colesevelam, no drug interaction was observed. Although colesevelam has a cleaner drug interaction profile than other bile acid sequestrants, it does interfere with absorption of some drugs. A 4-hour window appears sufficient to eliminate these interactions.

Objective: Clopidogrel is an oral thienopyridine antiplatelet agent indicated for the treatment of atherothrombotic events in patients with acute coronary syndrome (ACS). Prasugrel, a novel oral thienopyridine, is under investigation for the reduction of atherothrombotic events in patients with ACS undergoing percutaneous coronary intervention. Prasugrel's solubility decreases with increasing pH, suggesting that concomitantly-administered medications that increase gastric pH may lower the rate and/or extent of prasugrel absorption. This study evaluated the influence of ranitidine coadministration on the pharmacokinetics and pharmacodynamics of the respective active metabolite of prasugrel and clopidogrel.Research design and methods: In this open-label, two-period, two-treatment, crossover study, 47 healthy male subjects were randomized to one of two study arms, receiving either prasugrel (60-mg loading dose [LD], 10-mg maintenance dose [MD] for 7 days; n = 23) or clopidogrel (600-mg LD, 75-mg MD for 7 days; n = 24). In one treatment period, subjects received prasugrel or clopidogrel alone, and in the alternate period received the same thienopyridine with ranitidine (150 mg twice daily, starting 1 day before the LD). Pharmacokinetic parameter estimates (AUC(0-t last), C-max, and t(max)) and inhibition of platelet aggregation (IPA) by light transmission aggregometry were assessed at multiple time points after the LD and final MD.Results: Ranitidine had no clinically significant effect on the area under the plasma-concentration-time curve (AUC) and did not affect the time to Cmax (tmax) for active metabolites of either prasugrel or clopidogrel. It reduced the geometric mean maximum concentrations of active metabolite (C m) after a prasugrel and clopidogrel LD by 14% and 10%, respectively, but these differences were not statistically significant. When coadministered with a 60-mg prasugrel LD, ranitidine did not affect the time to, or magnitude of, peak IPA, but did result in a modest reduction at 0.5 h from 67.4 to 55.1% (p < 0.001). Ranitidine did not affect prasugrel IPA during MD. For clopidogrel, IPA was not affected by ranitidine. Prasugrel and clopidogrel were both well-tolerated, with/without ranitidine.Conclusions: Results from this study suggest that there is no significant drug-drug interaction between oral ranitidine therapy and concomitantly-administered prasugrel or clopidogrel.