Cardiac surgery in infective endocarditis and predictors of in-hospital mortality

INTRODUCTION

Infective endocarditis (IE) is a serious disease with significant in-hospital mortality (15-30%) despite advances in medical and surgical therapy.

AIMS

To perform a clinical characterization of patients undergoing cardiac surgery for IE and to identify factors that predict in-hospital mortality.

METHODS

We retrospectively analyzed 145 patients with IE admitted between January 2006 and October 2017.

RESULTS

The median age was 72 years. IE was acquired mainly in the community (69%), and involved the native aortic valve in 54% of patients, biological prosthetic valves in 22.1% and mechanical valves in 10.3%. Staphylococcus spp. (31.0%) were the most frequent etiological agents. Cardiac surgery was emergent in 29 patients, urgent in 108, and elective in eight. The main indications were heart failure (57.9%), large vegetations (20%), systemic embolism (17.2%) and valve dysfunction (15.2%). Overall, biological valves were implanted in 62.1% of patients and mechanical valves in 37.2%. A total of 19 patients (13.1%) died. Predictors of mortality were preoperative atrial fibrillation and lower left ventricular ejection fraction, postoperative severe valve regurgitation associated with cardiogenic shock, sepsis, septic shock associated with cardiogenic shock, cardiac tamponade, need for renal replacement therapy and, although without statistical significance, emergent surgery.

CONCLUSIONS

There is a need for better indicators to enable early identification of surgical candidates for IE, implementation of a heart team, and better surgical strategies, including more rapid intervention, more specific postoperative care, and optimal antibiotic therapy.

Abstract 565: Genome-wide miRNA Expression Profiling and OPLS Discriminant Analysis in Hypertension and Cardiac Disease

MicroRNAs (miRNAs) are regulators of gene expression and play a key role in the pathophysiology of various disease processes, namely cardiovascular disease. This study aimed at the identification of the miRNA expression pattern of peripheral blood mononuclear cells derived from hypertensive subjects (HT) and non-hypertensive subjects with cardiac disease (CD) using a genome-wide approach. Furthermore, we explored the potential of orthogonal partial least squares-discrimination analysis (OPLS-DA) to analyze miRNA expression data. The homogeneity of the population was assessed with Principal Component Analysis (PCA) and verified by the clear separation of the three groups on the basis of the miRNA expression levels. Moreover, local PCA of HT group indicates the splitting of this group in two distinct subgroups. This distinction correlates with two subject’s characteristics (smoking habits and history of myocardial infarction) that are closest to the CD group. OPLS-DA analysis confirms the separation of three groups and identified the most important miRNA to discrimination between groups. Among the most influential miRNA to the positive differentiation of HT from CD and control, several of them are relevant to endothelial dysfunction. On the other hand, miRNAs associated with angiogenesis positively differentiate CD from HT and control. Mir-186, a regulator of myogenin, is the most important miRNA to discriminate HT from CD. These results provide evidence of altered miRNA profile in hypertensives and cardiac disease and demonstrate that PCA and OPLS-DA are very useful and robust tools to analyze how different miRNAs contribute to the separations of groups and to find interesting patterns within the multidimensional data.

Effect of opicapone and entacapone upon levodopa pharmacokinetics during three daily levodopa administrations

BACKGROUND AND OBJECTIVES

Opicapone is a novel third generation catechol-O-methyltransferase (COMT) inhibitor. The purpose of this study was to compare the levodopa pharmacokinetic profile throughout a day driven by the COMT inhibition either following repeated doses of opicapone or concomitant administration with entacapone.

METHODS

A randomized, double-blind, gender-balanced, parallel-group study was performed in 4 groups of 20 healthy subjects each. Four subjects in each group received placebo during the entire study. Sixteen subjects in one group received placebo once daily for 11 days and on day 12, 200 mg entacapone concomitantly with each levodopa/carbidopa dose (three times separated by a 5-h interval). Sixteen subjects in each of the remaining three groups received respectively 25, 50, and 75 mg opicapone once daily for 11 days and on day 12, placebo concomitantly with each levodopa/carbidopa dose.

RESULTS

Levodopa minimum plasma concentration (Cmin) for each levodopa/carbidopa dose and for the mean of all levodopa/carbidopa doses increased substantially with all active treatments (entacapone and opicapone) when compared to the control group (placebo), with values ranging from 1.7-fold (200 mg entacapone) to 3.3-fold (75 mg opicapone). No statistical difference was found for levodopa peak of systemic exposure (as assessed by maximum observed plasma concentration (Cmax)) between all active treatments and placebo. A significant increase in the levodopa extent of systemic exposure (as assessed by concentration-time curve (AUC)) occurred with all opicapone treatments in relation to placebo. No statistical difference was found for levodopa AUC when entacapone was compared to placebo. When compared to entacapone, both 50 and 75 mg opicapone presented a significant increase for the levodopa AUC. All active treatments significantly inhibited both peak (as assessed by Emax) and extent (as assessed by effect-time curve (AUEC)) of the COMT activity in relation to placebo. When compared to entacapone, all opicapone treatments significantly decreased the extent (AUEC) of the COMT activity due to a long-lasting and sustained effect. The tolerability profile was favorable for all active treatments.

CONCLUSION

Opicapone, a novel third generation COMT inhibitor, when compared to entacapone, provides a superior response upon the bioavailability of levodopa associated to more pronounced, long-lasting, and sustained COMT inhibition. The tolerability profile was favorable. On the basis of the results presented in this study and along with the earlier pharmacology studies, it is anticipated that opicapone adjunct therapy at the dosages of 25 and 50 mg will provide an enhancement in levodopa availability that will translate into clinical benefit for Parkinson's disease patients.

Pharmacokinetics and tolerability of eslicarbazepine acetate and oxcarbazepine at steady state in healthy volunteers

PURPOSE

Investigate the pharmacokinetics of once-daily (QD; 900 mg) and twice-daily (BID; 450 mg) regimens of eslicarbazepine acetate (ESL) and BID (450 mg) regimen of oxcarbazepine (OXC) at steady state in healthy volunteers.

METHODS

Single-center, open-label, randomized, three-way (n = 12) crossover studies in healthy volunteers.

KEY FINDINGS

Mean eslicarbazepine Cmax,ss (in μm) following ESL QD (87.3) was 33.3% higher (p < 0.05) compared to ESL BID (65.5) and 82.1% higher (p < 0.05) compared to OXC BID (48.0). The mean area under the curve (AUC)ss,0-τ (in μmol h/L) following the last dose of an 8-day repeated dosing was 1156.3, 1117.6, and 968.4 for ESL QD, ESL BID, and OXC BID, respectively. The ratio eslicarbazepine plasma exposure (μmol h/L) to ESL daily-dose (μmol) was 0.381 (1156.3:3037.3), 0.368 (1117.6:3037.3), and 0.271 (968.4:3567.6) for ESL-QD, ESL-BID, and OXC-BID, respectively, which translates into a 40.6% increase in the ability of ESL-QD compared to OXC-BID to deliver into the plasma their major active entity eslicarbazepine. The extent of plasma exposure to ESL minor metabolites: (R)-licarbazepine and oxcarbazepine after ESL-QD was 71.5% and 61.1% lower, respectively, than after OXC-BID. Twenty, 24 and 38 treatment emergent adverse events were reported with ESL-QD, ESL-BID, and OXC-BID, respectively.

SIGNIFICANCE

ESL-QD resulted in 33.3% higher peak plasma concentration (Cmax,ss ) of eslicarbazepine and similar extent of plasma exposure (AUCss,0-τ ) when compared to ESL-BID, which may contribute to the efficacy profile reported with once-daily ESL. In comparison to OXC-BID, administration of ESL-QD resulted in 40.6% increase in the delivery of eslicarbazepine into the plasma as well as a significantly lower systemic exposure to (R)-licarbazepine and oxcarbazepine.

Effect of eslicarbazepine acetate on the pharmacokinetics of a combined ethinylestradiol/levonorgestrel oral contraceptive in healthy women

OBJECTIVE

To investigate the effect of once-daily (QD) eslicarbazepine acetate (ESL) 800 mg and 1,200 mg administration on pharmacokinetics of a combined ethinylestradiol/levonorgestrel oral contraceptive (OC) in women of childbearing potential.

METHODS

Two two-way, crossover, two-period, randomized, open-label studies were performed in 20 healthy female subjects, each. In one period (ESL+OC period), subjects received ESL 800 mg QD in one study and ESL 1200 mg QD in the other study, for 15 days; concomitantly with the Day 14 ESL dose, an oral single dose of 30 μg ethinylestradiol and 150 μg levonorgestrel was administered. In the other period (OC alone), a single dose of 30 μg ethinylestradiol and 150 μg levonorgestrel was administered. Three weeks or more separated the periods. An analysis of variance (ANOVA) was used to test for differences between pharmacokinetic parameters of 30 μg ethinylestradiol and 150 μg levonorgestrel following ESL+OC and OC alone, and 90% confidence intervals (90%CI) for the ESL+OC/OC alone geometric mean ratio (GMR) were calculated.

RESULTS

ESL significantly decreased the systemic exposure to both ethinylestradiol and levonorgestrel. GMR (90%CI) for AUC0-24 of ethinylestradiol were 68% (64%; 71%) following 1,200 mg ESL and 75% (71%; 79%) following 800 mg ESL. GMR (90%CI) for AUC0-24 of levonorgestrel were 76% (68%; 86%) following 1,200 mg ESL and 89% (82%; 97%) following 800 mg ESL.

CONCLUSIONS

A clinically relevant dose-dependent effect of ESL administration on the pharmacokinetics of ethinylestradiol and levonorgestrel was observed. Therefore, to avoid inadvertent pregnancy, women of childbearing potential should use other adequate methods of contraception during treatment with ESL, and, in case ESL treatment is discontinued, until CYP3A4 activity returns to normal.

Abstract 358: Signature microRNA Expression Pattern of Essential Hypertension in a Portuguese Population

Hypertension is a complex, multifactorial disease, and its development is determined by a combination of genetic susceptibility and environmental factors. microRNAs have been implicated in numerous biologic processes. Moreover, several studies have demonstrated associations between diseases and specific microRNAs, especially in the cardiovascular system. The present study we assessed the microRNA system in a Portuguese population of hypertensive subjects and explored the potential of microRNAs as biomarkers for essential hypertension. Using Agilent Human miRNA Microarrays, Release 16.0 in combination with a one-color based hybridization protocol and bioinformatic analysis, we determined the microRNA signature of peripheral blood mononuclear cells (PBMCs) from a total of 66 hypertensive subjects (divided into three classes: group 1, medicated HTA I and II; group 2, medicated HTA III; group 3, non-hypertensive with cardiac disease) and 13 non-hypertensive subjects. Bioinformatic analysis revealed 4 miRNAs (miR-4306, miR-146a, miR-22 and miR-146b-5pn) as upregulated not yet related to essential hypertension, and one (miR-186) previously described in myocardial infarction. Endothelial-specific miR-126, nephrosclerosis marker miR-192 and miR-98 (previously implicated in NO and ANP signaling) were found to be upregulated exclusively in group 1 comparing to control. Determining functions and identifying the specific targets of miR-4306, miR-146a, miR-22 and miR-146b-5pn, could determine their value as therapeutic targets for essential hypertension. Supported by FCT (PIC/IC/83204/2007)

Safety, tolerability, and pharmacokinetics of etamicastat, a novel dopamine-β-hydroxylase inhibitor, in a rising multiple-dose study in young healthy subjects

BACKGROUND

Activation of the sympathetic nervous system is an important feature in hypertension and congestive heart failure. A strategy for directly modulating sympathetic nerve function is to reduce the biosynthesis of norepinephrine (noradrenaline) via inhibition of dopamine-β-hydroxylase (DβH).

OBJECTIVE

To assess the safety, tolerability, and pharmacokinetics of etamicastat (BIA 5-453), a new DβH inhibitor, following repeated dosing.

METHODS

A double-blind, randomized, placebo-controlled study was conducted in healthy young male volunteers. Participants received once-daily doses of placebo or etamicastat 25, 50, 100, 200, 400, or 600 mg, for 10 days.

RESULTS

Etamicastat underwent N-acetylation to its metabolite BIA 5-961. Etamicastat and BIA 5-961 maximum concentrations were achieved at 1-3 and 2-4 hours, respectively, after dosing. Elimination half-lives ranged from 18.1 to 25.7 hours for etamicastat and 6.7 to 22.5 hours for BIA 5-961. Both etamicastat and BIA 5-961 followed linear pharmacokinetics. The extent of systemic exposure to etamicastat and BIA 5-961 increased in an approximately dose-proportional manner, and steady-state plasma concentrations were attained up to 9 days of dosing. Etamicastat accumulated in plasma following repeated administration. The mean observed accumulation ratio was 1.3-1.9 for etamicastat and 1.3-1.6 for BIA 5-961. Approximately 40% of the etamicastat dose was recovered in urine in the form of parent compound and BIA 5-961. There was a high variability in pharmacokinetic parameters, attributable to different N-acetyltransferase-2 (NAT2) phenotype. Urinary excretion of norepinephrine decreased following repeated administration of etamicastat. Etamicastat was generally well tolerated. There was no serious adverse event or clinically significant abnormality in clinical laboratory tests, vital signs, or ECG parameters.

CONCLUSION

Etamicastat was well tolerated. Etamicastat undergoes N-acetylation, which is markedly influenced by NAT2 phenotype. NAT2 genotyping could be a step toward personalized medicine for etamicastat.

TRIAL REGISTRATION

EudraCT No. 2007-004142-33.

Pharmacokinetics and tolerability of etamicastat following single and repeated administration in elderly versus young healthy male subjects: an open-label, single-center, parallel-group study

BACKGROUND

Etamicastat is a new dopamine-β-hydroxylase (DβH) inhibitor currently in clinical development for the treatment of hypertension and heart failure.

OBJECTIVES

To evaluate the pharmacokinetics and tolerability of etamicastat after single and repeated administration in elderly subjects (aged ≥65 years) relative to young adult healthy controls (aged 18-45 years).

METHODS

This was a single-center, open-label, parallel-group study in young male adults (n = 13; mean [SD] age 32.6 [16.4] years; range, 18-44 years; weight 79.0 [16.4] kg; systolic blood pressure 117 [12] mm Hg and diastolic blood pressure 61 [7] mm Hg) and 12 elderly male volunteers (n = 12; age 69.3 [3.3] years; weight 69.2 [9.5] kg; systolic blood pressure 115 [13] mm Hg and diastolic blood pressure 64 [4] mm Hg), conducted in 2 consecutive periods. All subjects were white, except for 1 black elderly subject. In Phase A, subjects received a single dose of 100 mg etamicastat. In Phase B, subjects received 100 mg/d etamicastat for 7 days. The pharmacokinetic parameters of etamicastat and its acetylated metabolite BIA 5-961 were calculated after the single dose of Phase A and the last dose of Phase B. Subjects' N-acetyltransferase type 1 (NAT1) and type 2 (NAT2) genotyping was performed and acetylator status inferred.

RESULTS

After a single dose of etamicastat 100 mg, mean (SD) plasma C(max) and plasma AUC(0-∞) were, respectively, 1.3 (0.5) ng/mL/kg and 12.4 (7.8) ng × h/mL/kg in elderly subjects, and 1.3 (0.4) ng/mL/kg and 10.0 (6.6) ng × h/mL/kg in young subjects. At steady-state, C(max) and AUC(0-24) were 1.8 (0.5) ng/mL/kg and 15.0 (6.4) ng × h/mL/kg in elderly subjects, and 1.5 (0.7) ng/mL/kg and 12.5 (6.5) ng × h/mL/kg in young subjects. Elderly/young geometric mean ratios and 90% CIs were, respectively, 0.944 (0.788-1.131) and 1.164 (0.730-1.855) for etamicastat C(max) and AUC(0-∞) after a single dose, and 1.225 (0.960-1.563) and 1.171 (0.850-1.612) for etamicastat C(max) and AUC(0-24) at steady state. Etamicastat steady-state plasma concentrations were reached after 3 to 4 days of dosing. The mean etamicastat accumulation ratio was 1.7 in both age groups. Following etamicastat single dose, mean (SD) BIA 5-961 C(max) and AUC(0-∞) were, respectively, 3.5 (2.1) ng/mL/kg and 28.4 (14.7) ng × h/mL/kg in elderly subjects, and 2.5 (1.5) ng/mL/kg and 16.5 (9.7) in young subjects. At steady state, BIA 5-961, C(max), and AUC(0-24) were 4.3 (2.6) ng/mL/kg and 34.6 (17.6) ng × h/mL/kg in elderly subjects, and 3.1 (2.0) ng/mL/kg and 22.2 (11.8) ng × h/mL/kg in young subjects. Large interindividual variability dependent on the NAT2 acetylator status was found in the pharmacokinetic parameters of etamicastat and BIA 5-961. Systemic exposure to etamicastat was higher and systemic exposure to BIA 5-961 was lower in NAT2 poor metabolizers compared with rapid metabolizers. No effect on heart rate and blood pressure was found in the young group. In the elderly, a decrease of supine blood pressure was observed. Postural changes in blood pressure were unaffected. Four adverse events (AEs) were reported by each group: nasopharyngeal pain, sciatica, asthenia, and back pain the elderly group, and headache (2 cases), insomnia, and myopericarditis by the young group. Myopericarditis led to study discontinuation for this subject and was considered to be of probable viral etiology. All other AEs were mild to moderate in intensity.

CONCLUSION

The pharmacokinetic profile of etamicastat was not significantly different in these small groups of healthy young versus elderly adult male volunteers.

Effect of food on the pharmacokinetic profile of etamicastat (BIA 5-453)

BACKGROUND

Etamicastat is a novel, potent, and reversible peripheral dopamine-β-hydroxylase inhibitor that has been administered orally at doses up to 600 mg once daily for 10 days to male healthy volunteers and appears to be well tolerated.

OBJECTIVE

The aim of this study was to investigate the effect of food on the pharmacokinetics of etamicastat.

MATERIAL AND METHODS

A single-center, open-label, randomized, two-way crossover study in 12 healthy male subjects was performed. Subjects were administered a single dose of etamicastat 200 mg following either a standard high-fat and high-calorie content meal (test) or 10 hours of fasting (reference). The statistical method for testing the effect of food on the pharmacokinetic parameters of interest was based upon the 90% confidence interval (CI) for the test/reference geometric mean ratio (GMR). The parameters of interest were maximum plasma concentration (C(max)), area under the plasma concentration-time curve (AUC) from time zero to the last measurable concentration (AUC(last)), and AUC from time zero to infinity (AUC(∞)). Bioequivalence was assumed when the 90% CI fell within the recommended acceptance interval (80, 125).

RESULTS

Etamicastat C(max), AUC(last), and AUC(∞) were 229 ng/mL, 1856 ng · h/mL, and 2238 ng · h/mL, respectively, following etamicastat in the fasting, and 166 ng/mL, 1737 ng · h/mL, and 2119 ng · h/mL, respectively, following etamicastat in the fed condition. Etamicastat test/reference GMR was 72.27% (90% CI 64.98, 80.38) for C(max), 93.59% (90% CI 89.28, 98.11) for AUC(last), and 96.47% (90% CI 91.67, 101.53) for AUC(∞). Time to C(max) was prolonged by the presence of food (p < 0.001). The C(max), AUC(last), and AUC(∞) values of the inactive metabolite BIA 5-961 were 275 ng/mL, 1827 ng · h/mL, and 2009 ng · h/mL, respectively, in the fasting, and 172 ng/mL, 1450 ng · h/mL, and 1677 ng · h/mL, respectively, in the fed condition. BIA 5-961 test/reference GMR was 62.42% (90% CI 56.77, 68.63) for C(max), 79.41% (90% CI 56.77, 68.63) for AUC(last), and 83.47% (90% CI 76.62, 90.93) for AUC(∞). A total of six mild to moderate unspecific adverse events were reported by four subjects. There was no clinically significant abnormality in laboratory assessments.

CONCLUSION

Etamicastat was well tolerated. The C(max) of etamicastat decreased 28% following oral administration of etamicastat in the presence of food, while AUC remained within the pre-defined acceptance interval. The delay in absorption and decrease in peak exposure of etamicastat is not clinically significant, and therefore etamicastat could be administered without regard to meals.

TRIAL REGISTRATION

EudraCT No. 2007-006530-33.

Chronopharmacology of nebicapone, a new catechol-O-methyltransferase inhibitor

OBJECTIVE

To investigate the chronopharmacology of nebicapone, a new catechol-O-methyltransferase (COMT) inhibitor currently being developed for use as an adjunct to levodopa/carbidopa or levodopa/benserazide in the treatment of Parkinson's disease.

METHODS

This was a double-blind, randomised, placebo-controlled, parallel-group study. Eighteen Caucasian subjects were randomly assigned to treatment with either nebicapone 100 mg (n = 6), nebicapone 200 mg (n = 6) or placebo (n = 6) at 4-h intervals for 7 days. First dose occurred at 8:00 AM on day 1 and last dose at 8:00 AM on day 8. Blood samples for the determination of plasma drug concentrations of nebicapone and its glucuronidated and methylated metabolites and for the assay of erythrocyte soluble COMT (S-COMT) activity were taken at frequent times following the first and last doses, and before the 8:00 AM and 8:00 PM doses on days 2-7.

RESULTS

Three men and three women in each group participated in the study. Mean +/- SD (range) age of study participants was 23.7 +/- 3.1 (21-28) years in the nebicapone 100 mg group, 22.2 +/- 0.4 (22-23) years in the nebicapone 200 mg group and 24.3 +/- 5.4 (18-32) in the placebo group. A circadian variation in the pre-dose nebicapone and nebicapone-glucuronide plasma concentrations was apparent. Both nebicapone and nebicapone-glucuronide levels were lower before the 8 PM dose in comparison to the 8 AM dose, suggesting that the absorption of nebicapone may follow a circadian variation. S-COMT activity showed no circadian variation in the placebo group. Therefore, the S-COMT activity variation found in nebicapone-treated subjects is considered to be due to changes in plasma concentrations of nebicapone, which is consistent with the fact that the pre-dose S-COMT activity was lower at the time at which nebicapone levels were maximal. Four subjects in the nebicapone 100 mg and placebo groups and six subjects in the nebicapone 200 mg group reported at least one adverse event (AE). All AEs were of mild or moderate intensity. Both nebicapone treatment regimens were subjectively well-tolerated, but a clinically relevant elevation in aspartate transaminase was observed in one subject of each nebicapone group.

CONCLUSION

Nebicapone showed chronopharmacology in young Caucasian healthy subjects. The clinical impact of the circadian variation in the nebicapone metabolism and activity in Parkinson's disease patients deserves evaluation as it may have implications for drug prescription by modulating the distribution of the total daily dose along the 24-h scale.

Pharmacokinetic-pharmacodynamic interaction between nebicapone, a novel catechol-o-methyltransferase inhibitor, and controlled-release levodopa/carbidopa 200 mg/50 mg : randomized, double-blind, placebo-controlled, crossover study in healthy subjects

BACKGROUND AND OBJECTIVES

Levodopa is the most effective symptomatic treatment for Parkinson's disease (PD), but its use is often associated with development of motor complications. These adverse responses to fluctuations in dopaminergic stimulation can be reduced by concomitant administration of a catechol-O-methyltransferase (COMT) inhibitor. Nebicapone is a new COMT inhibitor currently being developed for use as an adjunct to levodopa/dopa decarboxylase inhibitor in the treatment of PD. This article aimed to investigate the effect of single oral doses (50 mg, 100 mg and 200 mg) of nebicapone on levodopa pharmacokinetics and erythrocyte-soluble COMT (S-COMT) activity when coadministered with a single dose of controlled-release (CR) levodopa/carbidopa 200 mg/50 mg (Sinemet((R)) CR 200/50) in healthy subjects (n = 16).

METHODS

This was a randomized, double-blind, placebo-controlled, four-way crossover study in healthy subjects, with at least 5 days of washout between treatment periods.

RESULTS

There was a dose-dependent and significant increase in levodopa extent of exposure (area under the plasma concentration-time curve from time zero to infinity [AUC(infinity)]) without a significant change in peak exposure (maximum plasma concentration; [C(max)]). Using placebo as a reference, levodopa geometric mean ratios (GMRs) and 90% CIs following nebicapone 50 mg, 100 mg and 200 mg were, respectively, 1.13 (0.98, 1.30), 1.04 (0.90, 1.19) and 1.10 (0.96, 1.27) for C(max) and 1.26 (1.16, 1.34), 1.37 (1.27, 1.75) and 1.47 (1.42, 1.65) for AUC(infinity). For 3-O-methyldopa (3-OMD), the GMRs and 90% CIs were, respectively, 0.61 (0.55, 0.67), 0.45 (0.41, 0.50) and 0.33 (0.30, 0.36) for C(max) and 0.69 (0.61, 0.78), 0.53 (0.41, 0.61) and 0.41 (0.37, 0.47) for AUC(infinity). Nebicapone dose dependently and significantly decreased COMT activity. Maximum COMT inhibition occurred at 1.5-2.4 hours post-dose and ranged from 56% to 73% with nebicapone 50 mg and 200 mg, respectively. There was a good correlation between plasma concentrations of nebicapone and inhibition of S-COMT activity. Treatments were well tolerated.

CONCLUSION

Following concomitant administration with levodopa/carbidopa CR 200 mg/50 mg, single doses of nebicapone 50 mg, 100 mg and 200 mg significantly and dose-dependently inhibited S-COMT activity, increased systemic exposure to levodopa, and reduced 3-OMD formation.

Effect of nebicapone on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects

OBJECTIVE

Nebicapone is a new catechol-O-methyltransferase inhibitor. In vitro, nebicapone has showed an inhibitory effect upon CYP2C9, which is responsible for the metabolism of S-warfarin. The objective of this study was to investigate the effect of nebicapone on warfarin pharmacokinetics and pharmacodynamics in healthy subjects.

METHODS

Single-centre, open-label, randomised, two-period crossover study in 16 healthy volunteers. In one period, subjects received nebicapone 200 mg thrice daily for 9 days and a racemic warfarin 25-mg single dose concomitantly with the nebicapone morning dose on day 4 (test). In the other period, subjects received a racemic warfarin 25-mg single dose alone (reference). The treatment periods were separated by a washout of 14 days.

RESULTS

For R-warfarin, mean +/- SD C(max) was 1,619 +/- 284 ng/mL for test and 1,649 +/- 357 ng/mL for reference, while AUC(0-t ) was 92,796 +/- 18,976 ng x h/mL (test) and 73,597 +/- 11,363 ng x h/mL (reference). The R-warfarin test-to-reference geometric mean ratio (GMR) and 90% confidence interval (90%CI) were 0.973 (0.878-1.077) for C(max) and 1.247 (1.170-1.327) for AUC(0-t ). For S-warfarin, mean +/- SD C(max) was 1,644 +/- 331 ng/mL for test and 1,739 +/- 392 ng/mL for reference, while AUC(0-t ) was 66,627 +/- 41,199 ng x h/mL (test) and 70,178 +/- 42,560 ng x h/mL (reference). The S-warfarin test-to-reference GMR and 90%CI were 0.932 (0.845-1.028) for C(max) and 0.914 (0.875-0.954) for AUC(0-t ). No differences were found for the pharmacodynamic parameter (INR).

CONCLUSION

Nebicapone showed no significant effect on S-warfarin pharmacokinetics or on the coagulation endpoint (INR). A mild inhibition of the R-warfarin metabolism was found but is unlikely to be of clinical relevance.

Why healthy subjects volunteer for phase I studies and how they perceive their participation?

OBJECTIVE

To characterize the motivations and attitudes of healthy subjects who volunteer for phase I studies as well as their perception of the informed consent procedure and participation in the study.

METHODS

Subjects (n = 136, 48.5/51.5% males/females, 26.9 +/- 5.5 years; 51.9% students, 42.2% employed, 5.9% unemployed) anonymously answered questionnaires regarding study participation and personality (Revised NEO Personality Inventory).

RESULTS

Financial reward was the most important motivation and was most valued by subjects with a lower monthly income (p < 0.01) and lower education (p < 0.05). Personality traits correlated differently with the various motivators for participation. "Word-of-mouth" (mainly by ex-participants) was the source of information on the phase I study for 94.9% of the participants. Most (88.2%) subjects consulted other people (family member/partner, 53.3% of participants; friends, 40.0%; physician, 25.0%) before deciding to participate. In 80% of the cases, the people consulted recommended that the subject not participate, with the risk of serious complications being the main objection in 75.7% cases. The information provided was generally assessed favorably; 34.6% of subjects considered the discomfort caused by participation to be less than that originally reported during the consent procedure, 58.8% considered it to be identical and 6.6% considered it to be higher. Most of the subjects (81.6%) declared that they never felt at risk of a serious complication during their participation in the study, 16.2% occasionally felt that they were at risk and 2.2% felt that they were at risk for a significant period of time. Personality traits correlated with the decision to ask someone else's opinion, the manner in which information provided was rated and the perception of the risk taken during participation.

CONCLUSION

Financial reward as the main motivator for participation in phase I studies was less valued by healthy volunteers with a higher income and education. A subject's motivations and perceptions toward participation were found to be influenced by individual characteristics, including some personality traits.

Effect of Food on the Pharmacokinetic Profile of Eslicarbazepine Acetate (BIA 2-093)

OBJECTIVE

To investigate the effect of food on the pharmacokinetics of eslicarbazepine acetate (BIA 2-093), a new voltage-gated sodium channel antagonist.

MATERIAL AND METHODS

Single-centre, open-label, randomised, two-way crossover study in 12 healthy subjects. The study consisted of two consecutive treatment periods separated by a washout of 14 days or more. In each of the study periods subjects were administered a single dose of eslicarbazepine acetate 800 mg following either a standard high-fat content meal or 10 hours of fasting.

RESULTS

Eslicarbazepine acetate was rapidly and extensively metabolised to BIA 2-005. Maximum BIA 2-005 plasma concentrations (C(max)) in fed (test) and fasting (reference) conditions were, respectively, 12.8 +/- 1.8 microg/mL and 11.3 +/- 1.9 microg/mL, and the areas under the plasma concentration time curve from 0 to infinity (AUC(infinity)) were, respectively, 242.5 +/- 32.1 microg.h/mL and 243.6 +/- 31.1 microg.h/mL (arithmetic mean +/- SD). The point estimate (PE) and 90% confidence interval (90% CI) of the test/reference C(max )geometric mean ratio were 1.14 and 1.04, 1.25, respectively; for the AUC(infinity) ratio, the PE and 90% CI were 1.00 and 0.95, 1.04, respectively. Bioavailability of eslicarbazepine acetate administered in fed and fasting conditions was similar and bioequivalence is accepted for both AUC(infinity) and C(max) because the 90% CI lies within the acceptance range of 0.80-1.25. No statistically significant differences were found in time of occurrence of C(max).

CONCLUSION

The presence of food had no significant effect on the pharmacokinetics of eslicarbazepine acetate and therefore this new voltage-gated sodium channel antagonist may be administered without regard to meals.

Bioavailability and Bioequivalence of??Two Enteric-Coated Formulations of??Omeprazole in Fasting and Fed Conditions

OBJECTIVE

To investigate the relative bioavailability and bioequivalence, in fasting and fed conditions, of repeated doses of two omeprazole enteric-coated formulations in healthy volunteers.

MATERIAL AND METHODS

Open label, single-centre study consisting of two consecutive randomised, two-way crossover trials (a fasting trial and a fed trial). Each trial consisted of two 7-day treatment periods in which subjects received one daily dose of the test (Ompranyt((R))) or reference (Mopral((R))) formulations. At day 7 and day 14 (fasting trial), products were administered in fasting conditions and blood samples were taken for omeprazole plasma assay over 12 hours. At day 21 and day 28 (fed trial), products were administered after a standard high-calorie and high-fat meal and 12-hour blood samples taken. Omeprazole plasma concentrations were quantified by a validated method using a reverse-phase high performance liquid chromatography with UV detection (HPLC-UV).

RESULTS

Twenty-four subjects were enrolled and 23 completed the study. Under fasting conditions, the mean +/- SD maximum omeprazole plasma concentration (C(max)) was 797 +/- 471 mug/L for Ompranyt((R)) and 747 +/- 313 mug/L for Mopral((R)) with a point estimate (PE) of 1.01 and a 90% confidence interval (CI) of 0.88, 1.16. The mean +/- SD area under the plasma concentration curve from administration to last observed concentration (AUC(0-12)) was 1932 +/- 1611 mug . h/L and 1765 +/- 1327 mug . h/L for Ompranyt((R)) and Mopral((R)), respectively (PE = 1.09; 90% CI 0.95, 1.25). In the presence of food, the C(max) was 331 +/- 227 mug/L and 275 +/- 162 mug/L (PE = 1.21; 90% CI 0.92, 1.59) and AUC(0-12) was 1250 +/- 966 mug . h/L and 1087 +/- 861 mug . h/L (PE = 1.16; 90% CI 0.92, 1.47) for Ompranyt((R)) and Mopral((R)), respectively. Bioequivalence of the formulations in the fasting condition was demonstrated both for AUC(0-12) and for C(max) because the 90% CI lay within the acceptance range of 0.80-1.25. In contrast with the fasting condition, there were significant reductions in rate (C(max)) and extent (AUC(0-12)) of systemic exposure when test and reference formulations were administered with food. The food effect was more marked with Mopral((R)) than with Ompranyt((R)), and the bioequivalence criterion was not fulfilled because the 90% CI fell out of the acceptance range of 0.80, 1.25, for both C(max) and AUC(0-12). The two formulations were similarly well tolerated.

CONCLUSION

Bioequivalence of Ompranyt((R)) (test formulation) and Mopral((R)) (reference) formulations was demonstrated after repeated dosing in the fasting condition. Following a high-calorie and high-fat meal, there was a significant reduction in rate and extent of systemic exposure for both products, with Ompranyt((R)) being less affected than Mopral((R)) by the presence of food.

Pharmacokinetic-pharmacodynamic interaction between BIA 3-202, a novel COMT inhibitor, and levodopa/carbidopa

This study investigated the tolerability and the pharmacokinetic and pharmacodynamic interactions between single oral administration of BIA 3-202 (50 mg, 100 mg, 200 mg, and 400 mg), a novel catechol-O-methyltransferase (COMT) inhibitor, and standard carbidopa/levodopa 25 mg/100 mg (Sinemet 25/100) in healthy adult volunteers. This was a single-center, double-blind, placebo-controlled, randomized, crossover study with 5 single-dose treatment periods with a washout period of 2 weeks between doses. During each treatment period, a different dose of BIA 3-202 or placebo was administered concomitantly with Sinemet 25/100. Tolerability was assessed by recording adverse events, vital signs, continuous EKG, and clinical laboratory parameters. Pharmacokinetic parameters of levodopa and 3-O-methyl-levodopa (3-OMD) were determined. The activity of soluble COMT in erythrocytes was also measured. Eighteen subjects (10 men and 8 women) participated in the study. The drug combination was well tolerated, with the adverse events reported being transient and generally mild in severity. Mean levodopa Cmax values were attained at 0.8 to 1.8 hours postdose. Thereafter, plasma levodopa levels declined with a mean t1/2 that increased in a manner that depended on the dose of BIA 3-202. The increase in systemic exposure to levodopa (AUC0-infinity) occurred at all doses of BIA 3-202, attaining its maximum at 200 mg BIA 3-202 (95% conficence interval, 1.43-1.73). The mean Cmax and AUC0-infinity values of 3-OMD decreased dose proportionally in BIA 3-202-treated subjects, with differences being statistically significant for all the doses tested. Maximum COMT inhibition occurred between 0.8 and 2.0 hours postdose, and ranged from 56 (50 mg) to 85% (400 mg). Time to return to baseline COMT activity ranged from 6 (50 mg) to 18 hours (400 mg), following the same dose-dependent tendency. In conclusion, the novel COMT inhibitor BIA 3-202 increased the bioavailability of levodopa and reduced the formation of 3-OMD when administered with standard levodopa/carbidopa.

[Endothelin system and heart failure: a potential therapeutic target]

Neurohormonal activation is a marker and one of the most important pathophysiologic aspects of heart failure. The hyperactivation and participation of the endothelin system in several manifestations of this syndrome have been widely documented in the last few years. These data support attempts to view the endothelin system as a potential pharmacological target in order to reduce the high morbidity and mortality associated with heart failure. This is a short review of the main aspects of endothelin biology, its mechanisms of action, including those at the molecular level, and its pathophysiological role in heart failure. Finally, the potential benefits of the pharmacological manipulation of the endothelin system as well as some results of clinical trials in this context will be presented.

Pharmacokinetic-pharmacodynamic interaction between BIA 3-202, a novel COMT inhibitor, and levodopa/benserazide

BIA 3-202 is a novel catechol-O-methyltransferase (COMT) inhibitor being developed for use as a levodopa-sparing agent in Parkinson's disease. This study investigated the effect of four single oral doses of BIA 3-202 (50 mg, 100 mg, 200 mg, and 400 mg) compared with placebo on plasma concentrations of levodopa and its metabolite 3- O-methyl-levodopa (3-OMD) and on inhibition of erythrocyte COMT in healthy subjects receiving 100 mg of levodopa and 25 mg of benserazide (Madopar 125). This was a single-centre, double-blind, placebo-controlled, randomised, crossover study with five single-dose treatment periods. The washout period between doses was 2 weeks. On each treatment period, a different dose of BIA 3-202 or placebo was administered concomitantly with Madopar 125. Tolerability was assessed by recording adverse events, vital signs, continuous electrocardiogram and clinical laboratory parameters. In the study, 18 subjects (12 male and 6 female) participated. The drug combination was well tolerated. All doses of BIA 3-202 significantly increased the area under the concentration-time curve (AUC) versus placebo, ranging from 39% (95% confidence intervals, 1.06-1.69) with 50 mg to 80% (95% confidence intervals, 1.42-2.22) with 400 mg. No significant change in mean maximum plasma concentrations (C(max)) of levodopa was found. Mean C(max) and AUC of 3-OMD significantly decreased for all doses tested. BIA 3-202 caused a rapid and reversible inhibition of S-COMT activity, ranging from 57% (50 mg) to 84% (400 mg). In conclusion, the novel COMT inhibitor BIA 3-202 was well tolerated and significantly increased the bioavailability of levodopa and reduced the formation of 3-OMD when administered with standard release levodopa/benserazide.

[Angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor antagonists. Pharmacologic features]

The development of pharmacological agents that block the renin-angiotensin system (RAS) specifically have helped to define all the components of the system and their contribution to blood-pressure control and to the pathogenesis of hypertension, congestive heart failure and chronic renal failure. The angiotensin converting-enzyme inhibitors (ACEi) are among all available drugs that interfere with the RAS, the most efficient, so far, in the treatment of several cardiovascular diseases, with comfortable posologic schemes and an acceptable safety profile. The most important difference between them are more related to pharmacokinetic profile rather than to pharmacodynamic characteristics. With the use of ACEi the interference with other neurohumoral systems is unavoidable and the controversy has been pharmacologically and clinically installed. With the advent of oral selective AT1 angiotensin II receptor blockers (ARB) the pharmacological interference became eventually much more selective. Their antihypertensive efficacy is identical and their tolerability is better than that showed by ACEi. The ARBs differ mainly in their pharmacokinetics and in their binding capacity to the AT1 angiotensin receptor. The results of several ongoing clinical trials will show if the ARBs as ACEi will be capable to protect target-organs and to promote a significant reduction in cardiovascular morbility and mortality. In parallel there is an intense experimental and clinical research with other groups of drugs which also markedly interfere with RAS: renin inhibitors, chymase inhibitors and simultaneous inhibitors of vasopeptidases (ACE, endothelin converting-enzyme, neutral endopeptidase). From the pharmacological point of view, it is now possible to block effectively RAS with some relevant clinical results that will be certainly widen in the near future.

The role of the endocardium in the facilitatory effect of bradykinin on electrically-induced release of noradrenaline in rat cardiac ventricle

1. The present investigation was undertaken to study the role of bradykinin in noradrenaline release from the ventricle of the rat induced by electrical stimulation. Slices of the left ventricle of adult Wistar rats with or without endocardium were previously loaded with 0.2 microM [3H]-noradrenaline and washed out before electrical stimulation was applied. 2. Bradykinin (0.1-100 nM) concentration-dependently increased tritium release evoked by electrical stimulation (EC50 = 3.5 (1.2-10.2) nM; n = 12). The angiotensin converting enzyme inhibitor, captopril (1 microM), which per se had no effect on tritium release, caused a marked enhancement of the bradykinin facilitatory effect, shifting the concentration-response curve of bradykinin to the left by about one log unit. The compound Hoe 140, a selective inhibitor of B2-bradykinin receptors, competitively antagonized the effect of bradykinin, indicating the involvement of these receptors in the action of bradykinin. 3. In endocardium-free ventricle, bradykinin had no effect either in the absence or in the presence of captopril. 4. These results show that: (1) bradykinin is able to facilitate noradrenaline release evoked by electrical stimulation of the rat ventricle through activation of B2-bradykinin receptors located on endocardial cells; (2) this action of bradykinin which is markedly potentiated by the inhibition of the angiotensin-converting enzyme seems to be exerted through the release of some factor which is formed in the endocardium and diffuses into the myocardium where it acts.