Pharmacokinetics of the novel PAR-1 antagonist vorapaxar in patients with hepatic impairment.

PURPOSE: To determine whether hepatic impairment has an effect on the pharmacokinetics (PK) of vorapaxar or M20, its main pharmacologically active metabolite. METHODS: This was an open-label study in which a single 40-mg oral dose of vorapaxar was administered to patients with mild (n = 6), moderate (n = 6), and severe (n = 4) hepatic impairment and healthy controls (n = 16) matched for age, gender, weight, and height. Blood samples for vorapaxar and M20 assay were collected predose and at frequent intervals up to 8 weeks postdose. RESULTS: Plasma vorapaxar and M20 PK profiles were similar between patients with impaired liver function and healthy controls. Group mean values for vorapaxar C(max) and AUC(tf) were 206-279 ng/mL and 14,200-18,200 ng·h/mL, respectively, with the lowest values observed in patients with severe impairment. Vorapaxar median T(max) and mean t(1/2) values were 1.00-1.75 h and 298-366 h, respectively. There was no apparent correlation between vorapaxar or M20 exposure or t(1/2) values and disease severity. Vorapaxar was generally well tolerated; one serious adverse event (gastrointestinal bleeding secondary to ruptured esophageal varices) was reported in a patient with severe hepatic impairment. CONCLUSIONS: Hepatic impairment had no clinically relevant effect on the PK of vorapaxar and M20. No dose or dosage adjustment of vorapaxar will be required in patients with mild to moderate hepatic impairment. Although systemic exposure to vorapaxar does not appear to increase in patients with severe hepatic impairment, administration of vorapaxar to such patients is not recommended given their bleeding diathesis.

No differences in the pharmacodynamics and pharmacokinetics of the thrombin receptor antagonist vorapaxar between healthy Japanese and Caucasian subjects.

BACKGROUND: Vorapaxar, a novel antiplatelet agent in advanced clinical development for the prevention and treatment of atherothrombotic disease, is a potent, orally bioavailable thrombin receptor antagonist selective for the protease-activated receptor 1 (PAR-1). METHODS: Since race/ethnicity may affect the safety, efficacy and dosage of drugs, this study was conducted to evaluate potential differences in the pharmacodynamics, pharmacokinetics and safety of vorapaxar after single (5, 10, 20, or 40 mg) or multiple (0.5, 1, or 2.5 mg once daily) doses in healthy Japanese and matched (gender, age, height, and weight) Caucasian volunteers. RESULTS: Vorapaxar was well tolerated in both Japanese and Caucasian subjects. Pharmacodynamic and pharmacokinetic profiles of vorapaxar in the two racial/ethnic groups were similar. In both racial groups, complete inhibition of platelet aggregation was achieved most rapidly with vorapaxar 40 mg and was consistently achieved and maintained with a 2.5 mg daily maintenance dose. CONCLUSION: There were no substantial differences in the safety, pharmacokinetics or pharmacodynamics of vorapaxar between Japanese and Caucasian subjects.

Pharmacokinetics and pharmacodynamics of the novel PAR-1 antagonist vorapaxar in patients with end-stage renal disease.

PURPOSE: To determine whether impaired renal function alters the pharmacokinetics (PK) of vorapaxar or its ability to inhibit thrombin receptor agonist peptide (TRAP)-induced platelet aggregation. METHODS: This was an open-label study in which 8 patients with end-stage renal disease (ESRD) on hemodialysis and 7 matched (based on age, gender, weight, and height) healthy controls were administered a single 10-mg oral dose of vorapaxar. Blood samples for vorapaxar PK and pharmacodynamic analysis were collected predose and at frequent intervals up to 6 weeks postdose. RESULTS: Mean vorapaxar bioavailability (based on area under the curve of plasma vorapaxar concentration over time) was identical in the two subject groups; the ESRD/healthy geometric mean ratio (GMR, expressed in percent) was 98. Mean maximum observed plasma concentration (77.4-98.2 ng/mL) was numerically lower in patients with ESRD compared with matched controls (GMR=76; 90% confidence interval=48 to 118). Median time of maximum observed plasma concentration was 2 h in both subject groups. The observed means for elimination half-life were 186 and 231 h in the ESRD and control groups, respectively. Inhibition of platelet aggregation was similar in the two groups. Four out of 15 (27%) subjects reported adverse events, all of which were characterized by the investigator as mild and unrelated to treatment. CONCLUSIONS: ESRD had no clinically relevant effect on the PK profile of vorapaxar or its ability to inhibit TRAP-induced platelet aggregation.

Characteristics of youths with hearing loss admitted to substance abuse treatment.

The purpose of this study is to provide a profile of youths with hearing loss admitted to substance abuse treatment facilities. Intake data on 4,167 youths (28% female; 3% reporting a hearing loss) collected via the Global Appraisal of Individual Need-I assessment was used for the analyses. Information on demographics, environmental characteristics, substance use behaviors, and symptoms of co-occurring psychological problems for youths with and without a hearing loss was analyzed via Pearson chi-square tests and effect sizes. The groups reported similar backgrounds and comparable rates of marijuana and alcohol use. However, youths in the hearing loss group reported substance use behaviors indicative of a more severe level of involvement. Across all measures of co-occurring symptoms, youths with hearing loss reported greater levels of distress and were more often victims of abuse. Results of this study will help inform treatment needs of youths with hearing loss and define a baseline for future research.

Development of MK-8353, an orally administered ERK1/2 inhibitor, in patients with advanced solid tumors.

BACKGROUND: Constitutive activation of ERK1/2 occurs in various cancers, and its reactivation is a well-described resistance mechanism to MAPK inhibitors. ERK inhibitors may overcome the limitations of MAPK inhibitor blockade. The dual mechanism inhibitor SCH772984 has shown promising preclinical activity across various BRAFV600/RAS-mutant cancer cell lines and human cancer xenografts. METHODS: We have developed an orally bioavailable ERK inhibitor, MK-8353; conducted preclinical studies to demonstrate activity, pharmacodynamic endpoints, dosing, and schedule; completed a study in healthy volunteers (P07652); and subsequently performed a phase I clinical trial in patients with advanced solid tumors (MK-8353-001). In the P07652 study, MK-8353 was administered as a single dose in 10- to 400-mg dose cohorts, whereas in the MK-8353-001 study, MK-8353 was administered in 100- to 800-mg dose cohorts orally twice daily. Safety, tolerability, pharmacokinetics, pharmacodynamics, and antitumor activity were analyzed. RESULTS: MK-8353 exhibited comparable potency with SCH772984 across various preclinical cancer models. Forty-eight patients were enrolled in the P07652 study, and twenty-six patients were enrolled in the MK-8353-001 study. Adverse events included diarrhea (44%), fatigue (40%), nausea (32%), and rash (28%). Dose-limiting toxicity was observed in the 400-mg and 800-mg dose cohorts. Sufficient exposure to MK-8353 was noted that correlated with biological activity in preclinical data. Three of fifteen patients evaluable for treatment response in the MK-8353-001 study had partial response, all with BRAFV600-mutant melanomas. CONCLUSION: MK-8353 was well tolerated up to 400 mg twice daily and exhibited antitumor activity in patients with BRAFV600-mutant melanoma. However, antitumor activity was not particularly correlated with pharmacodynamic parameters. TRIAL REGISTRATION: ClinicalTrials.gov NCT01358331. FUNDING: Merck Sharp & Dohme Corp., a subsidiary of Merck & Co. Inc., and NIH (P01 CA168585 and R35 CA197633).

Boston Society's 11th Annual Applied Pharmaceutical Analysis conference.

Boston Society's 11th Annual Applied Pharmaceutical Analysis conference, Hyatt Regency Hotel, Cambridge, MA, USA, 14-16 September 2015 The Boston Society's 11th Annual Applied Pharmaceutical Analysis (APA) conference took place at the Hyatt Regency hotel in Cambridge, MA, on 14-16 September 2015. The 3-day conference affords pharmaceutical professionals, academic researchers and industry regulators the opportunity to collectively participate in meaningful and relevant discussions impacting the areas of pharmaceutical drug development. The APA conference was organized in three workshops encompassing the disciplines of regulated bioanalysis, discovery bioanalysis (encompassing new and emerging technologies) and biotransformation. The conference included a short course titled 'Bioanalytical considerations for the clinical development of antibody-drug conjugates (ADCs)', an engaging poster session, several panel and round table discussions and over 50 diverse talks from leading industry and academic scientists.

Vorapaxar, an oral PAR-1 receptor antagonist, does not affect the pharmacokinetics of rosiglitazone.

PURPOSE: To evaluate the potential effects of vorapaxar on the pharmacokinetics and safety of rosiglitazone. METHODS: This was an open-label, two-period, two-treatment, fixed-sequence study in 18 healthy subjects. On Day 1, Period 1, subjects received a single dose of rosiglitazone 8 mg. In Period 2, subjects received vorapaxar 40 mg on Day 1, vorapaxar 7.5 mg once-daily on Days 2-7, and a single dose of rosiglitazone 8 mg on Day 7. Rosiglitazone and N-desmethylrosiglitazone pharmacokinetics were assessed alone (Period 1) and after coadministration with vorapaxar (Period 2). Vorapaxar and its M20 metabolite pharmacokinetics were assessed on Day 7, Period 2. Safety and tolerability were assessed throughout the study. RESULTS: Coadministration of rosiglitazone with vorapaxar had no effect on rosiglitazone or N-desmethylrosiglitazone pharmacokinetics. The ratio of geometric means (GMR) and 90% confidence intervals (CI) of the coadministration versus monotherapy for Cmax (GMR 95; 90% CI 88, 103) and AUC0-24 h (GMR 103; 90% CI 98, 108) were within the 80-125% bioequivalence criteria. The metabolite-to-parent exposure ratio with and without vorapaxar was unaltered. Coadministration of vorapaxar with rosiglitazone was generally well tolerated. CONCLUSION: Coadministration of vorapaxar with rosiglitazone or drugs metabolized via CYP2C8 is unlikely to cause a significant pharmacokinetic interaction.

The effect of multiple doses of ketoconazole or rifampin on the single- and multiple-dose pharmacokinetics of vorapaxar.

This randomized, open-label, parallel-group study evaluated the effects of multiple-dose ketoconazole or rifampin on the single- and multiple-dose pharmacokinetics of vorapaxar. Healthy subjects randomly received one of the following three treatments (N = 12/group): (1) ketoconazole 400 mg once daily (QD) for 28 days (Days 1-28) and single-dose vorapaxar 20 mg on Day 7 followed by vorapaxar 2.5 mg QD for 21 days (Days 8-28); (2) rifampin 600 mg QD for 28 days (Days 1-28) and single-dose vorapaxar 20 mg on Day 7 followed by vorapaxar 2.5 mg QD for 21 days (Days 8-28); and (3) placebo QD for 28 days (Days 1-28) and single-dose vorapaxar 20 mg on Day 7 followed by vorapaxar 2.5 mg QD for 21 days (Days 8-28). Ketoconazole increased the steady-state vorapaxar AUC(0-24 h) and C(max) by approximately twofold (GMR [90% CI]: 196% [173,222]; 193% [166,223], respectively), while rifampin decreased vorapaxar AUC(0-24 h) and C(max) by approximately 50% (GMR [90% CI]: 45.5% [40,52]; 61.4% [52,72], respectively) versus vorapaxar alone. Potent CYP3A4 inhibitors or inducers may cause moderate increases or decreases in vorapaxar exposure, respectively, which may have safety and/or efficacy implications; therefore, their concomitant use with vorapaxar is not recommended.

The Influence of Multiple-Dose Vorapaxar, an Oral PAR-1 Receptor Antagonist, on the Single-Dose Pharmacokinetics and Pharmacodynamics of Digoxin.

Vorapaxar is a novel orally active thrombin receptor antagonist selective for the PAR-1 receptor. This open-label, single-center, fixed-sequence, 2-period, 2-treatment study assessed the pharmacokinetics and pharmacodynamics of single-dose digoxin in the presence/absence of multiple-dose vorapaxar. Eighteen healthy adult subjects received two treatments in a fixed sequence separated by ≥8-day washout: (A) digoxin 0.5 mg (Day 1); (B) vorapaxar 2.5 mg/day Days 1-6 and single-dose vorapaxar 40 mg administered with single-dose digoxin 0.5 mg Day 7. The geometric mean ratio (%; GMR) for the two treatments (digoxin alone and digoxin plus vorapaxar) and 90% confidence intervals (CIs) for and AUCtf and Cmax of digoxin were calculated. Pharmacodynamics of digoxin was assessed by measuring changes in electrocardiogram (ECG) parameters. The GMR (90% CIs) estimates for digoxin AUCtf and Cmax were 105% (91, 121) and 154% (130, 181), respectively. Except for differences in peak plasma concentrations, the pharmacokinetics of digoxin were similar between the two treatments. Coadministration of vorapaxar plus digoxin had no effect on digoxin Tmax or ECG parameters. The results of this study suggest that the coadministration of vorapaxar and digoxin is unlikely to cause a clinically significant drug-drug interaction.

Effect of Food, Antacid, and Age on the Pharmacokinetics of the Oral Thrombin Receptor Antagonist Vorapaxar (SCH 530348) in Healthy Volunteers.

This randomized, open-label, parallel group study examined the effects of food, antacid, and age on the pharmacokinetics of vorapaxar. In total, 101 subjects were enrolled including 83 young adults (18-45 years) and 18 elderly subjects (>65 years). Subjects received single-dose vorapaxar 40 mg after a 10-hour fast (young and elderly) or with extra-strength antacid, food, or 1 or 2 hours after food (young only). Vorapaxar 40 mg was rapidly absorbed after a fast (median Tmax : 1 hour). Administration with food or 1 or 2 hours post-meal modestly increased vorapaxar mean area under the curve (AUC) and Cmax and prolonged median Tmax by 1 hour. Concomitant food modestly increased vorapaxar AUC from time zero to infinity [AUC(I)] and Cmax 43% and 31%, respectively. Antacid modestly decreased vorapaxar AUC(I) by 15% and Cmax by 38%, and increased median Tmax by 1 hour. Vorapaxar AUC(I) and Cmax were 41% and 29% higher, respectively, in elderly versus young subjects. Concomitant food and older age were associated with modest increases, and antacid was associated with a small decrease in vorapaxar exposure, which are not expected to affect the drug's safety or efficacy.

Determination of a novel thrombin receptor antagonist (SCH 530348) in human plasma: evaluation of Ultra Performance Liquid Chromatography™-tandem mass spectrometry for routine bioanalytical analysis.

SCH 530348 is a safe and effective oral anti-platelet agent for patients with acute coronary syndrome. Clinical study results suggest that SCH 530348 dosage at 20 mg or 40 mg is feasible to achieve rapid maximum platelet inhibition following an acute coronary event or intervention procedure. To permit accurate determinations of circulating SCH 530348 in plasma following dosing, a method for measuring SCH 530348 concentrations in human plasma was validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method utilized semi-automated 96-well protein precipitation with gradient chromatography using an ACQUITY™ UPLC BEH C18 (2.1 mm×50 mm, 1.7 µm) column. The retention time of SCH 530348 was approximately 1.5 min. This method was validated for routine quantitation of SCH 530348 over the concentration range of 1.00-1000 ng/mL. Inter-run accuracy based on mean percent theoretical for replicate quality control samples was better than 95.2%. Inter-run precision based on percent relative deviation for replicate quality control samples was ≤3.3%. SCH 530348 quality control samples were stable in human plasma for up to three freeze/thaw cycles, for at least 467 days when frozen at -20 °C and for at least 7 h when stored at room temperature. The lower limit of quantitation was 1.00 ng/mL for a 100 µL plasma aliquot.