A population analysis of the DGAT1 inhibitor GSK3008356 and its effect on endogenous and meal-induced triglyceride turnover in healthy subjects

Non-alcoholic steatohepatitis (NASH) is a liver disease in which fatty infiltration is accompanied by liver inflammation. GSK3008356 is under development as a selective inhibitor of diacylglycerol acyltransferase 1 (DGAT1), a key enzyme involved in the formation of triglyceride (TG). Decreased DGAT1 activity can reduce circulating TG and liver TG, and therefore could potentially prevent or treat NASH. The aim of the current study was to develop a population pharmacokinetic-pharmacodynamic (PKPD) model that characterizes the PK disposition of GSK3008356 and its relation to the changes in blood TG. Drug concentrations were measured in 104 healthy adults receiving various single (SD) and repeat doses (RD) in a first time in human (FiH) study. A 30% fat meal was given at hour 2 postdose, and blood postprandial TG concentrations were measured at various time points. The population PKPD model consists of several parts including a PK model, drug effect model, meal effect model, and a turnover model. The pharmacokinetic data were described using a 3-compartment model. Drug effect was described by an inhibitory sigmoidal Emax model. Since TG levels change with the introduction of a meal, a bi-exponential meal effect model was utilized. The total change in TG was fitted using a turnover model with drug and meal effects on the TG production rate. The current analysis presents a PKPD modeling strategy of time-varying TG data coming from both endogenous and exogenous sources. In general, the presented model could be utilized in the model-based drug development of drugs that influence TG levels in blood.

Pharmacokinetics, Safety, and Tolerability Evaluation of Single and Multiple Doses of GSK3342830 in Healthy Volunteers

This was a first-time-in-human randomized, double-blind, single-center, placebo-controlled dose-escalation study to determine the safety, tolerability, and pharmacokinetic (PK) profiles of GSK3342830 after single and repeat intravenous doses in healthy adult subjects (NCT0271424). Sixty-two subjects were enrolled: 48 subjects in part 1 (single dose) and 14 subjects in part 2 (multiple doses). Following single intravenous infusions, total systemic exposure of GSK3342830 was dose proportional over the 250- to 6000-mg dose range evaluated, whereas peak exposure was approximately dose proportional over the dose range. Following repeat intravenous infusions 3 times a day, GSK3342830 showed time invariance with no drug accumulation. Steady state was reached before day 3, and approximately 90% of GSK3342830 was excreted unchanged in urine. All 48 subjects in part 1 (100.0%) completed the study. In part 2, 9 subjects (64.3%) completed the study, and 5 subjects, all receiving GSK3342830, discontinued early (35.7%), 4 after experiencing fever, headache, and malaise, whereas 1 subject met predefined criteria for drug discontinuation because of transaminitis. GSK3342830 demonstrated PK consistent with other cephalosporin-class antibiotics but poor tolerability following multiple doses in healthy volunteers.

The drug interaction potential of daprodustat when coadministered with pioglitazone, rosuvastatin, or trimethoprim in healthy subjects

This study was conducted to evaluate the likelihood of daprodustat to act as a perpetrator in drug–drug interactions (DDI) with the CYP2C8 enzyme and OATP1B1 transporter using the probe substrates pioglitazone and rosuvastatin as potential victims, respectively. Additionally, this study assessed the effect of a weak CYP2C8 inhibitor, trimethoprim, as a perpetrator of a DDI with daprodustat.

This was a two‐part study: Part A assessed the effect of coadministration of daprodustat on the pharmacokinetics of pioglitazone and rosuvastatin in 20 subjects; Part B assessed the coadministration of trimethoprim on the pharmacokinetics of daprodustat in 20 subjects.

Coadministration of 100 mg of daprodustat with pioglitazone or rosuvastatin had no effect on the plasma exposures of either probe substrate. When trimethoprim was coadministered with 25‐mg daprodustat plasma daprodustat AUC and C_max increased by 48% and 28%, respectively. Additionally, AUC and C_max for the metabolite GSK2531401 were decreased by 32% and 40%, respectively. C_max for the other metabolites was slightly decreased (~8–15%) but no changes in AUC were observed.

As 100‐mg daprodustat exceeds the planned top therapeutic dose, interaction potential of daprodustat as a perpetrator with substrates of the CYP2C8 enzyme and OATP1B1 transporters is very low. Conversely, daprodustat exposure (AUC and C_max) is likely to increase moderately with coadministration of weak CYP2C8 inhibitors.

Intrapulmonary pharmacokinetics of GSK2251052 in healthy volunteers

The plasma and intrapulmonary pharmacokinetics (PK) of intravenous (i.v.) GSK2251052, a novel boron-containing antimicrobial, were evaluated in healthy adult subjects. Thirty subjects underwent bronchoscopy and timed bronchoalveolar lavage (BAL) either following a single dose (cohort 1) or after 5 twice-daily doses (cohort 2) of 1,500 mg GSK2251052 i.v. Serial PK and safety assessments were obtained throughout the study. Bronchoscopy was performed on a single occasion in each subject at 2, 6, or 12 h after start of infusion. Noncompartmental analysis was performed to calculate PK parameters. Thirty subjects completed the study. The mean clearance (CL), volume of distribution at steady state (Vss), and half-life (t1/2) values were 22 liters/h, 231 liters, and 10.7 h, respectively. Approximately 30% of the dose was excreted unchanged in urine. The GSK2251052 concentrations in epithelial lining fluid (ELF) and alveolar macrophages (AM) were approximately 50% and 500 to 600%, respectively, compared to the concentration in plasma. the GSK2251052 exposures in ELF and AM were comparable following single- and repeat-dose administration. The most frequently reported drug-related adverse event (AE) was mild to moderate infusion site reactions (7 subjects) that occurred primarily in the repeat-dose cohort. No serious drug-related AEs or clinically significant trends in laboratory values, vital signs, or electrocardiograms were observed. GSK2251052 given as a 1,500-mg infusion was generally tolerated following single- or repeat-dose administration. GSK2251052 distributes into both the ELF and AM of healthy volunteers, which supports further study in patients with pneumonia.

Steady-state pharmacokinetics of carvedilol and its enantiomers in patients with congestive heart failure

Carvedilol is a relatively new drug with beta- and alpha 1-receptor blocking activity and antioxidant effects recently approved for the treatment of congestive heart failure (CHF). An ascending, multiple-dose study was completed in 20 male patients with stable New York Heart Association (NYHA) Class III or IV CHF. The pharmacokinetics of carvedilol, S(-)-carvedilol, R(+)-carvedilol, and the active metabolites of carvedilol was assessed at steady state after twice-daily oral administration of carvedilol for 7 days at 6.25, 12.5, 25, and 50 mg doses. Carvedilol exhibited stereoselective pharmacokinetics in CHF patients with dose-proportional increases in steady-state plasma concentrations of carvedilol and its enantiomers. Mean AUC and Cmax values for carvedilol were up to twofold higher in patients with Class IV CHF as compared to those with Class III CHF. Steady-state plasma concentrations of the active metabolites also increased in a dose-proportional manner and were typically 10% or less of that observed for carvedilol. In general, carvedilol was adequately tolerated by adult male CHF patients at the dose levels (6.25-50 mg) evaluated in this study as adverse events were consistent with those frequently observed in patients with CHF.

Pharmacokinetics of intravenously and orally administered eprosartan in healthy males: absolute bioavailability and effect of food

Eighteen healthy males received a single 300 mg oral dose of eprosartan as the commercial wet granulation formulation under fasting conditions and following a high-fat breakfast and a single 20 mg intravenous (i.v.) dose. The pharmacokinetics of i.v. eprosartan (mean +/- S.D.) were characterized by a low systemic plasma clearance (131.8 +/- 36.2 mL min(-1)) and a small steady-state volume of distribution (12.6 +/- 2.6 L). Oral bioavailability averaged 13.1%, due to incomplete absorption. In vitro dynamic flow cell dissolution data showed that pH-dependent aqueous solubility of eprosartan is one factor which limits absorption. Eprosartan terminal half-life was shorter after i.v. (approximately 2 h) versus oral (approximately 5-7 h) administration, which may be due to detection of an additional elimination phase or absorption rate-limited elimination following oral administration. Oral administration of eprosartan following a high-fat meal compared with fasting conditions resulted in a similar extent of absorption (based on AUC), but a decreased absorption rate. Cmax was approximately 25% lower, and a median delay of 1.25 h in time to Cmax was observed when eprosartan was administered with food. These minor changes in exposure are unlikely to be of clinical consequence; therefore, eprosartan may be administered without regard to meal times.

Pharmacokinetics and protein binding of eprosartan in healthy volunteers and in patients with varying degrees of renal impairment

This was an open-label, parallel group study to compare the pharmacokinetics of multiple oral doses of eprosartan in subjects with normal renal function (Clcr > 80 mL/min; n = 8) and patients with mild (Clcr 60-80 mL/min; n = 8), moderate (Clcr 30-59 mL/min; n = 15), or severe (Clcr < 30 mL/min; n = 3) renal insufficiency. Each subject received oral eprosartan 200 mg twice daily for 6 days and a single dose on day 7. Mean total maximum concentration (Cmax) and area under the concentration-time curve from 0 to 12 hours (AUC0-12) were similar for healthy subjects and those with mild renal impairment, but were an average of 25% to 35% and 51% to 55% greater for patients with moderate and severe renal impairment, respectively, compared with healthy subjects. Mean renal clearance (Clr), which was similar for healthy subjects and patients with mild renal impairment, was decreased an average of 41% and 95% in the groups with moderate and severe renal impairment, respectively, compared with normal subjects. Eprosartan was highly bound to plasma proteins in all groups; however, the unbound fraction was increased approximately two-fold in the group with severe renal impairment. Mean unbound Cmax and AUC0-12 were an average of 53% to 61% and 185% to 210% greater for the patients with moderate and severe renal impairment, respectively, compared with healthy subjects. Headache was the most common adverse experience reported in all subgroups. Eprosartan was safe and well tolerated regardless of degree of renal impairment. Cmax and AUC were increased and renal clearance decreased in patients with moderate to severe renal impairment in comparison to healthy subjects and patients with mild renal impairment. However, based on the moderate renal clearance and known safety profile of eprosartan, it is not necessary to adjust the dose of eprosartan in patients with renal insufficiency.

Effect of hepatic disease on the pharmacokinetics and plasma protein binding of eprosartan

STUDY OBJECTIVE

To evaluate the pharmacokinetics and plasma protein binding of eprosartan in hepatic disease.

DESIGN

Single-dose, parallel-group study.

SETTING

Oklahoma Foundation for Digestive Research, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma.

PATIENTS

Eight healthy subjects with normal hepatic function and eight patients with hepatic disease.

INTERVENTION

All subjects received a single oral dose of eprosartan 100 mg.

MEASUREMENTS AND MAIN RESULTS

Eprosartan plasma concentrations were quantified by high-performance liquid chromatography; plasma protein binding was determined by ultrafiltration. Using analysis of variance, point estimates (PE) and 90% CIs were calculated. Total and unbound maximum concentrations and degree of plasma protein binding were similar for both groups. Total area under the plasma concentration-time curve (AUC0-t) was approximately 40% higher for the group with hepatic disease (PE 1.42, 90% CI 0.94-2.14). Similarly, unbound AUC0-t was approximately 50% higher (PE 1.53, 90% CI 0.98-2.39).

CONCLUSION

Eprosartan was safe and well tolerated by both groups. Based on the increase in AUC in patients with hepatic disease compared with those with normal hepatic function, the dosage of eprosartan in patients with hepatic disease should be individualized based on tolerability and response.

Lack of effect of eprosartan on the single dose pharmacokinetics of orally administered digoxin in healthy male volunteers

AIMS

To study the effect of eprosartan, a nonbiphenyl tetrazole angiotensin II receptor antagonist, on digoxin pharmacokinetics in a randomized, open-label, two period, period balanced crossover study in 12 healthy men.

METHODS

Each subject received a single 0.6 mg oral dose of digoxin (Lanoxicaps 0.2 mg/capsule, Glaxo Wellcome) alone or following 4 days of dosing with eprosartan 200 mg orally every 12 h. Each study period was separated by a 14 day washout interval. Serial blood samples were obtained for up to 96 h after each digoxin dose for determination of digoxin pharmacokinetics. The effect of eprosartan on digoxin pharmacokinetics was assessed through an equivalence-type approach using AUC(0, t') as the primary endpoint.

RESULTS

For AUC(0, t'), the ratio of digoxin+eprosartan: digoxin alone was 0.99 with a 90% confidence interval (CI) of [0.90, 1.09]. For Cmax, the ratio was 1.00 with a 90% CI of [0.86, 1.17]. tmax was similar for both regimens. Both regimens were safe and well tolerated.

CONCLUSIONS

Based on AUC and Cmax data, it can be concluded that eprosartan has no effect on the pharmacokinetics of a single oral dose of digoxin.