Association of baseline factors with 1-year outcomes in the SB11-ranibizumab equivalence trial: A post hoc analysis

PURPOSE

To identify baseline factors associated with 1-year outcomes when treating neovascular age-related macular degeneration (nAMD) with ranibizumab biosimilar SB11 or reference ranibizumab (rRBZ), and to compare efficacy of the two products within subgroups judged to be clinically relevant.

DESIGN

Post hoc analysis of a prospective, equivalence phase 3 randomized clinical trial (RCT) METHODS: 705 patients with nAMD were randomized 1:1 to receive SB11 or rRBZ for 48 weeks. Pooled and randomized groups were used to identify baseline factors associated with clinical outcomes at Week 52 using multiple linear regression models. Significant factors identified in regression analyses were confirmed in analyses of variance. Subgroup analyses comparing best-corrected visual acuity (BCVA) changes between SB11 and rRBZ were conducted.

RESULTS

634 (89.9%) participants completed the 52-week visit. Regression analyses showed that younger age, lower BCVA, and smaller total lesion area at baseline were associated with greater BCVA gain at Week 52, while older age, lower BCVA, and thicker central subfield thickness (CST) at baseline were predictors of greater CST reduction in the pooled group. Subgroup analyses demonstrated that BCVA outcomes appeared comparable for the SB11 and rRBZ groups.

CONCLUSION

Post hoc analyses of the SB11-rRBZ equivalence study showed that baseline age, BCVA, CST, and total lesion area were prognostic factors for visual and anatomical outcomes of nAMD, while subgroup analyses demonstrated comparable results for SB11 and rRBZ. Collectively, the results appear comparable to similar RCTs of anti-vascular endothelial growth factor reference products for nAMD and strengthen confidence in the biosimilarity of SB11.

Exposure-response analysis using time-to-event data for bevacizumab biosimilar SB8 and the reference bevacizumab

Purpose: This analysis aimed to characterize the exposure-response relationship of bevacizumab in non-small-cell lung cancer (NSCLC) and evaluate the efficacy of SB8, a bevacizumab biosimilar, and Avastin®, the reference bevacizumab sourced from the European Union (EU), based on the exposure reported in a comparative phase III efficacy and safety study (EudraCT, 2015-004026-34; NCT02754882). Materials and methods: The overall survival (OS) and progression-free survival (PFS) data from 224 patients with steady-state trough concentrations (Css,trough) were analyzed. A parametric time-to-event (TTE) model was developed using NONMEM®, and the effects of treatments (SB8 and bevacizumab-EU) and patient demographic and clinical covariates on OS and PFS were evaluated. Simulations of median OS and PFS by bevacizumab Css,trough were conducted, and concentrations required to achieve 50% and 90% of the maximum median TTE were computed. Results: A log-logistics model with Css,trough best described the OS and PFS data. Treatment was not a predictor of the hazard for OS or PFS. Simulations revealed steep exposure-response curves with a phase of rapid rise before saturating to a plateau. The median Css,trough values of SB8 and bevacizumab-EU reported from the clinical study were on the plateaus of the exposure-response curves. The concentrations required to achieve 50% and 90% of the maximum effect were 82.4 and 92.2 μg/mL, respectively, for OS and 79.7 and 89.1 μg/mL, respectively, for PFS. Conclusion: Simulations based on the constructed TTE models for OS and PFS have well described the exposure-response relationship of bevacizumab in advanced NSCLC. The analysis demonstrated comparable efficacy between SB8 and bevacizumab-EU in terms of OS and PFS based on their exposure levels.

Interchangeability for Biologics is a Legal Distinction in the USA, Not a Clinical One

Biologics are increasingly vital medicines that significantly reduce morbidity as well as mortality, yet access continues to be an issue even in apparently wealthy countries, such as the USA. While patient access is expected to improve with the introduction of biosimilars, misperceptions in a significant part based on terminology continue to make a sustained contribution by biosimilars difficult. Patients are and will continue to suffer needlessly if biosimilars continue to be impugned. Consequently, it is increasingly urgent that semantics are clarified, and in particular, the implication that interchangeable biologics are better biosimilars dismissed. This paper distinguishes between the real differences between biologics that matter clinically to patients and discusses the actual meaning of a US Food and Drug Administration designation of interchangeability for a biosimilar product. This will help highlight where there is need for further Food and Drug Administration education and which stakeholders likely need that education the most.

Para-aminosalicylic acid significantly reduced tenofovir exposure in human subjects: Mismatched findings from in vitro to in vivo translational research

AIMS

Tenofovir and para-aminosalicylic acid (PAS) may be coprescribed to treat patients with concomitant infections of human immunodeficiency virus and Mycobacterium tuberculosis bacteria. Both drugs are known to have remarkable renal uptake transporter-mediated clearance. Owing to the lack of clinical studies on drug-drug interaction between the 2 drugs, we conducted a translational clinical study to investigate the effect of PAS on tenofovir pharmacokinetics (PK).

METHODS

Initially, we studied in vitro renal uptake transporter-mediated drug-drug interactions using stably transfected cells with human organic anion transporters (OAT1 and OAT3). Later, we estimated clinical drug interactions using static and physiologically based PK modelling. Finally, we investigated the effects of PAS-calcium formulation (PAS-Ca) on tenofovir disoproxil fumarate PK in healthy male Korean subjects.

RESULTS

PAS inhibited OAT1- and OAT3-mediated tenofovir uptake in vitro. The physiologically based PK drug-drug interaction model suggested a 1.26-fold increase in tenofovir peak plasma concentration when coadministered with PAS. By contrast, an open-label, randomized, crossover clinical trial evaluating the effects of PAS-Ca on tenofovir PK showed significantly altered geometric mean ratio (90% confidence intervals) of maximum plasma concentration (C_max ) and area under the curve (AUC_0-inf ) by 0.33 (0.28-0.38) and 0.29 (0.26-0.33), respectively.

CONCLUSION

Our study findings suggest that the PAS-Ca formulation significantly reduced systemic exposure to tenofovir through an unexplained mechanism, which was contrary to the initial prediction. Caution should be exercised while predicting in vivo PK profiles from in vitro data, particularly when there are potential confounders such as pharmaceutical interactions.

Pharmacokinetics and relative bioavailability of fixed-dose combination of clopidogrel and aspirin versus coadministration of individual formulations in healthy Korean men

Background

Simultaneous prescription of clopidogrel and low-dose aspirin is recommended for the treatment of acute coronary syndrome because of improvements in efficacy and patient compliance. In this study, the pharmacokinetics of a fixed-dose combination (FDC) of clopidogrel and aspirin was compared with coadministration of individual formulations to clarify the equivalence of the FDC.

Methods

This was a randomized, open-label, two-period, two-treatment, crossover study in healthy Korean men aged 20–55 years. Subjects received two FDC capsules of clopidogrel/aspirin 75/100 mg (test) or two tablets of clopidogrel 75 mg and two capsules of aspirin 100 mg (reference) with a 14-day washout period. Plasma concentrations of clopidogrel, aspirin, and salicylic acid were measured using validated ultraperformance liquid chromatography–tandem mass spectrometry. Bioequivalence was assessed by analysis of variance and calculation of the 90% confidence intervals (CIs) of the ratios of the geometric means (GMRs) for AUC_last and C_max for clopidogrel and aspirin.

Results

Sixty healthy subjects were enrolled, and 53 completed the study. Clopidogrel, aspirin, and salicylic acid showed similar absorption profiles and no significant differences in C_max, AUC_last, and T_max between FDC administration and coadministration of individual formulations. The GMRs (90% CI) for the C_max and AUC_last of clopidogrel were 1.08 (0.95, 1.23) and 0.93 (0.84, 1.03), respectively. The GMRs (90% CI) for the C_max and AUC_last of aspirin were 0.98 (0.84, 1.13) and 0.98 (0.93, 1.04), respectively. Both treatments were well tolerated in the study subjects.

Conclusion

The FDC of clopidogrel and aspirin was bioequivalent to coadministration of each individual formulation. The FDC capsule exhibited similar safety and tolerability profiles to the individual formulations. Therefore, clopidogrel/aspirin 75 mg/100 mg FDC capsules can be prescribed to improve patient compliance.

Inhibitory Interaction Potential of 22 Antituberculosis Drugs on Organic Anion and Cation Transporters of the SLC22A Family

Twenty-two currently marketed antituberculosis drugs were comprehensively evaluated for their inhibitory effect on organic anionic transporter (OAT)- and organic cation transporter (OCT)-mediated uptake using stably transfected HEK293 cells in vitro We observed moderate to strong inhibitory effects on OAT1- and OAT3-mediated para-aminohippurate (PAH) uptake and OCT1- and OCT2-mediated N-methyl-4-phenylpylidinium acetate (MPP+) uptake. Ciprofloxacin, linezolid, para-aminosalicylic acid (PAS), and rifampin were observed to have strong inhibitory effects, with the concentrations for a 50% inhibitory effect (IC50s) being 35.1, 31.1, 37.6, and 48.1 μM, respectively, for OAT1 and >100, 21.9, 24.6, and 30.2 μM, respectively, for OAT3. Similarly, pyrazinamide, rifabutin, and levofloxacin were observed to have inhibitory effects, with IC50 values being 36.5, 42.7, and 30.3 μM, respectively, for OCT1 and with the IC50 value for PAS being 94.2 μM for OCT2. In addition, we used zidovudine and metformin as clinically prescribed substrates of OATs and OCTs, respectively, and zidovudine and metformin uptake was also strongly inhibited by the antituberculosis drugs. Among the tested drugs, the highest drug-drug interaction (DDI) indexes were found for PAS, which were 9.3 to 13.9 for OAT1 and 12.0 to 17.7 for OAT3, and linezolid, which were 1.18 to 2.15 for OAT1 and 1.7 to 3.01 for OAT3. Similarly, the DDI indexes of pyrazinamide and levofloxacin were 0.57 and 0.30, respectively, for OCT1, and the DDI index of PAS was 3.8 for OCT2, suggesting a stronger possibility (DDI index value cutoff, >0.1) of in vivo DDIs. This is the first comprehensive report of the inhibitory potential of anti-TB drugs on OAT- and OCT-mediated uptake of prototype and clinically prescribed substrate drugs in vitro, providing an ability to predict DDIs between anti-TB drugs and other coprescribed drugs in clinical studies in vivo.

Population Pharmacokinetic Analysis of Piperacillin/Tazobactam in Korean Patients with Acute Infections

Background

For more effective and safer usage of antibiotics, the dosing strategy should be individualized based on the patients’ characteristics, including race. The aim of this study was to investigate the population pharmacokinetic (PK) profiles of piperacillin and tazobactam in Korean patients with acute infections.

Materials and Methods

At least four consecutive 2/0.25 g or 4/0.5 g doses of piperacillin/tazobactam (TZP) were intravenously infused over 1 h every 8 h for patients with creatinine clearance (CL_cr) ≤50 ml/min or CL_cr >50 mL/min, respectively. Blood samples from 33 patients at a steady-state were taken pre-dose and at 0 min, 30 min, and 4-6 h after the fourth infusion. The population PK analysis was conducted using a non-linear mixed-effects method. A likelihood ratio test was used to select significant covariates, with significance levels of P <0.05 for selection and P <0.01 for elimination.

Results

Both piperacillin PK and tazobactam PK were well described by a two-compartment model with first-order elimination. Creatinine clearance and body weight, as covariates on clearance (CL) and volume of central compartment (V1), were selected among the covariates possibly affecting PK parameters of both drugs. CL was defined as CL = 2.9 + 4.03 × CL_cr /47 for piperacillin and CL = 1.76 + 4.81 × CL_cr /47 for tazobactam. V1 was defined as V1 = 19.5 × weight/60 for piperacillin and V1 = 22.6 × weight/60 for tazobactam.

Conclusion

The PK profiles of TZP at a steady-state in Korean patients with acute infections were well described by a two-compartment model with first-order elimination. Both piperacillin and tazobactam clearances were significantly influenced by creatinine clearance.

Association between lutein intake and lutein concentrations in human milk samples from lactating mothers in South Korea

This study was performed to investigate the association between maternal lutein intake and lutein concentrations in human milk among exclusive breast-feeding and mixed-feeding groups of lactating mothers in South Korea. From 99 women who were recruited from March to July 2015, dietary data and breast milk samples were obtained. The means of the daily lutein intakes and breast milk lutein concentrations in lactating mothers were 4.04 mg/day and 10.06 μg/dl, respectively, and they did not differ according to the type of breast-feeding. Breast milk lutein concentrations were positively correlated with the dietary lutein intake of lactating mothers after adjustment for the infant's age and supplement use by the lactating women (r=0.3337, P=0.0008). These correlations appeared in both groups. Further research is needed to identify whether breast milk lutein levels influence infant health, especially eye health.European Journal of Clinical Nutrition advance online publication, 25 May 2016; doi:10.1038/ejcn.2016.84.

The Effect of Age on the Pharmacokinetics of Udenafil in Healthy Subjects

Udenafil, a cyclic guanosine monophosphate-specific phosphodiesterase type 5 inhibitor, has been developed to treat erectile dysfunction. We evaluated the effect of age on the pharmacokinetics and tolerability of udenafil. A single-center, open-label, parallel-group phase 1 study was conducted in healthy adult subjects who took a single oral dose of udenafil (100 mg). The pharmacokinetics and tolerability of udenafil were compared between 12 healthy young men (21-27 years) and 12 healthy elderly men (65-78 years). Serial blood and urine samples were collected for up to 60 and 48 hours after dosing. The plasma concentrations of udenafil and its major metabolite, DA-8164, were analyzed using a validated liquid chromatography-tandem mass spectrometry method. The mean C_max of udenafil tended to be slightly less (214.0 vs 292.8 μg/L) in the elderly compared with the young (GMR, 68.9; 95% CI, 48.9-97.1); however, the AUC did not differ between the groups (1858.8 vs 2100.6 μg·h/L; GMR, 84.6; 95% CI, 66.1-108.4). The mean t_1/2 was prolonged by approximately 5 hours in the elderly (P < .05). The clearance and metabolic AUC ratio did not differ between the elderly and young. In terms of tolerability, all adverse events were mild, and all subjects recovered without additional therapy. The systemic exposure of elderly subjects to udenafil appears to be comparable to or slightly less than that of young healthy subjects. Based on our pharmacokinetic comparisons, udenafil dose adjustment is unlikely to be required in the elderly population.

Population plasma and urine pharmacokinetics of ivabradine and its active metabolite S18982 in healthy Korean volunteers

Ivabradine, a selective inhibitor of the pacemaker current (If ), is used for heart failure and coronary heart disease and is mainly metabolized to S18982. The purpose of this study was to explore the pharmacokinetics (PK) of ivabradine and S18982 in healthy Korean volunteers. Subjects in a phase I study were randomized to receive 2.5, 5, or 10 mg of ivabradine administered every 12 hours for 4.5 days, and serial plasma and urine concentrations of ivabradine and S18982 were measured. The plasma PK of ivabradine was best described by a 2-compartment model with mixed 0- and first-order absorption, linked to a 2-compartment model for S18982. The introduction of interoccasional variabilities and period as covariate into absorption-related parameters improved the model fit. Urine data have been applied to estimate renal and nonrenal clearance, enabling a more detailed description of the elimination process. We developed a population PK model describing the plasma and urine PK of ivabradine and S18982 in healthy Korean adult males. This model might be useful for predicting the plasma and urine PK of ivabradine, potentially helping to identify the optimal dosing regimens in various clinical situations.

A proposal for an individualized pharmacogenetic-guided isoniazid dosage regimen for patients with tuberculosis

BACKGROUND/AIM

Isoniazid (INH) is an essential component of first-line anti-tuberculosis (TB) treatment. However, treatment with INH is complicated by polymorphisms in the expression of the enzyme system primarily responsible for its elimination, N-acetyltransferase 2 (NAT2), and its associated hepatotoxicity. The objective of this study was to develop an individualized INH dosing regimen using a pharmacogenetic-driven model and to apply this regimen in a pilot study.

METHODS

A total of 206 patients with TB who received anti-TB treatment were included in this prospective study. The 2-hour post-dose concentrations of INH were obtained, and their NAT2 genotype was determined using polymerase chain reaction and sequencing. A multivariate regression analysis that included the variables of age, sex, body weight, and NAT2 genotype was performed to determine the best model for estimating the INH dose that achieves a concentration of 3.0-6.0 mg/L. This dosing algorithm was then used for newly enrolled 53 patients.

RESULTS

Serum concentrations of INH were significantly lower in the rapid-acetylators than in the slow-acetylators (2.55 mg/L vs 6.78 mg/L, median, P<0.001). A multivariate stepwise linear regression analysis revealed that NAT2 and body weight independently affected INH concentrations: INH concentration (mg/L) = 13.821-0.1× (body weight, kg) -2.273× (number of high activity alleles of NAT2; 0, 1, 2). In 53 newly enrolled patients, the frequency at which they were within the therapeutic range of 3.0-6.0 mg/L was higher in the model-based treatment group compared to the standard treatment group (80.8% vs 59.3%).

CONCLUSION

The use of individualized pharmacogenetic-guided INH dosage regimens that incorporate NAT2 genotype and body weight may help to ensure achievement of therapeutic concentrations of INH in the TB patients.

Effects of amoxicillin/clavulanic acid on the pharmacokinetics of valproic acid

Valproic acid (VPA) is mainly metabolized via glucuronide, which is hydrolyzed by β-glucuronidase and undergoes enterohepatic circulation. Amoxicillin/clavulanic acid (AMC) administration leads to decreased levels of β-glucuronidase-producing bacteria, suggesting that these antibiotics could interrupt enterohepatic circulation and thereby alter the pharmacokinetics of VPA. This study aimed to evaluate the effects of AMC on the pharmacokinetics of VPA. This was an open-label, two-treatment, one-sequence study in 16 healthy volunteers. Two treatments were evaluated; treatment VPA, in which a single dose of VPA 500 mg was administered, and treatment AMC + VPA, in which multiple doses of AMC 500/125 mg were administered three times daily for 7 days and then a single dose of VPA was administered. Blood samples were collected up to 48 hours. Pharmacokinetic parameters were calculated using noncompartmental methods. Fifteen subjects completed the study. Systemic exposures and peak concentrations of VPA were slightly lower with treatment AMC + VPA than with treatment VPA (AUC_last, 851.0 h·mg/L vs 889.6 h·mg/L; C_max, 52.1 mg/L vs 53.0 mg/L). There were no significant between-treatment effects on pharmacokinetics (95% confidence interval [CI]) of AUC_last and C_max (95.7 [85.9–106.5] and 98.3 [91.6–105.6], respectively). Multiple doses of AMC had no significant effects on the pharmacokinetics of VPA; thus, no dose adjustment is necessary.

Pharmacokinetic comparison of sustained- and immediate-release formulations of cilostazol after multiple oral doses in fed healthy male Korean volunteers

Background

A new extended-release form of cilostazol has recently been developed. This study was conducted to compare the pharmacokinetic characteristics of sustained-release (SR) and immediate-release (IR) formulations of cilostazol after multiple oral doses in healthy male Korean volunteers.

Methods

This was an open-label, randomized, multiple-dose, crossover study conducted in 30 healthy Korean subjects. In each treatment period, subjects received oral doses of 200 mg SR formulation every 24 hours or 100 mg IR formulation every 12 hours for 5 consecutive days in a fed state, with a washout period of 9 days. The plasma concentrations of cilostazol and its metabolites were determined using a validated liquid chromatography-tandem mass spectrometry method. The area under the plasma concentration–time curve within a dosing interval (AUC_T), the measured peak plasma concentration at steady state (C_max,ss), and the time to reach C_max,ss (t_max,ss) were analyzed using a noncompartmental method.

Results

A total of 24 healthy male subjects completed the study. The mean (standard deviation [SD]) AUC_T (96–120 hours) values for SR and IR were 27,378.0 (10,301.6) ng·h/mL and 27,860.3 (7,152.3) ng·h/mL, respectively. The mean (SD) C_max,ss values were 2,741.4 (836.0) ng/mL and 2,051.0 (433.2) ng/mL, respectively. The median t_max,ss values were 8.0 hours and 4.0 hours, respectively. The geometric mean ratios (90% confidence intervals) of the SR to IR formulations were 0.937 (0.863–1.017), 0.960 (0.883–1.043), and 0.935 (0.859–1.017) for AUC_T and 0.644 (0.590–0.703), 0.586 (0.536–0.642), and 0.636 (0.577–0.702) for dose-normalized C_max,ss of cilostazol, OPC-13015 (3,4-dehydro-cilostazol), and OPC-13213 (4′-trans-hydroxyl-cilostazol), respectively. All formulations were well tolerated.

Conclusion

At steady state, the AUC_T of cilostazol SR 200 mg is comparable to that of cilostazol IR 100 mg twice a day in healthy male Korean subjects. Both formulations are well tolerated.

Multiple-Dose Study to Evaluate Pharmacokinetics, Pharmacodynamics, and Safety in Healthy Subjects: A Comparison of Controlled-Release Sarpogrelate and Immediate-Release Sarpogrelate

AIMS

To compare the pharmacokinetics, pharmacodynamics, and safety of sarpogrelate between controlled-release (CR) and immediate-release (IR) formulations after multiple-dose administration.

METHODS

This study was a randomized, open-label, 2-period, 2-treatment, crossover study in healthy subjects. All subjects received CR sarpogrelate 300 mg once daily and IR sarpogrelate 100 mg three times daily by random order each for 3 days with a 7-day washout period. Serial blood sampling was performed over 24 h. Pharmacokinetic parameters were determined by noncompartmental methods. Platelet aggregation to collagen, measured by light transmission aggregometry, was reported as maximal platelet aggregation.

RESULTS

Thirty-two subjects completed the study. CR sarpogrelate increased rapidly, reaching Cmax in 1.25 h (vs. 1.00 h in IR sarpogrelate) and declined with a t1/2 of 3.59 h (vs. 1.12 h in IR sarpogrelate). The 90% CIs for the geometric mean ratio of AUCτ and Cmax,ss between IR and CR formulations were 1.18 to 1.40 and 0.99 to 1.29, respectively. The degree of inhibition of platelet aggregation was similar between two formulations.

CONCLUSIONS

CR sarpogrelate showed slightly higher systemic exposure and similar peak concentration compared with IR sarpogrelate. The profiles of pharmacodynamics and safety were comparable between two formulations.

Bioequivalence evaluation of two amlodipine salts, besylate and orotate, each in a fixed-dose combination with olmesartan in healthy subjects

A fixed-dose combination of amlodipine and olmesartan is used to treat high blood pressure in patients whose hypertension is not sufficiently controlled with either drug alone. The objective of this study was to evaluate the bioequivalence of two fixed-dose combinations, ie, amlodipine orotate/olmesartan medoxomil 10/40 mg and amlodipine besylate/olmesartan medoxomil 10/40 mg, in healthy subjects. A randomized, open-label, single-dose, two-sequence, two-period, crossover study was conducted in 30 healthy adult volunteers. Blood samples were collected for up to 72 hours post-dose in each period. Safety data included the results of physical examinations, clinical laboratory tests, vital signs, an electrocardiogram, and adverse events. For both amlodipine and olmesartan, the 90% confidence intervals for the geometric mean ratios of AUC_last and time to peak plasma concentration fell within the bioequivalence acceptance criteria. The two fixed-dose combinations showed similar safety profiles. Amlodipine orotate/olmesartan medoxomil 10/40 mg was bioequivalent to amlodipine besylate/olmesartan medoxomil 10/40 mg.

A pharmacokinetic and pharmacodynamic drug interaction between rosuvastatin and valsartan in healthy subjects

PURPOSE

Valsartan, an angiotensin-receptor blocker, and rosuvastatin, a competitive inhibitor of the 3-hydroxy-3-methylglutaryl coenzyme A reductase, are frequently coadministered to treat patients with hypertension and dyslipidemia. The study reported here sought to evaluate the pharmacokinetic and pharmacodynamic interactions between rosuvastatin and valsartan in healthy Korean subjects.

SUBJECTS AND METHODS

Thirty healthy male Korean subjects were administered with rosuvastatin (20 mg/day), valsartan (160 mg/day), and both drugs concomitantly for 4 days in a randomized, open-label, multiple-dose, three-treatment, three-period crossover study. Plasma concentrations of rosuvastatin, N-desmethyl rosuvastatin, and valsartan were determined using validated high-performance liquid chromatography with tandem mass spectrometry. Lipid profiles and vital signs (systolic and diastolic blood pressure and pulse rate) were measured for the pharmacodynamic assessment.

RESULTS

For rosuvastatin, the geometric mean ratios (90% confidence intervals [CIs]) of coadministration to mono-administration were 0.8809 (0.7873-0.9857) for maximum plasma concentration at steady state and 0.9151 (0.8632-0.9701) for area under the concentration-time curve (AUC) over a dosing interval at steady state. For valsartan, the geometric mean ratios (90% CIs) of those were 0.9300 (0.7946-1.0884) and 1.0072 (0.8893-1.1406), respectively. There were no significant differences in the metabolic ratio of N-desmethyl rosuvastatin AUC to rosuvastatin AUC between coadministration and rosuvastatin alone. No interaction was found in terms of systolic or diastolic blood pressure or lipid profiles. Combined treatment with valsartan and rosuvastatin was generally well tolerated without serious adverse events.

CONCLUSION

The pharmacokinetic profiles of rosuvastatin and valsartan in combination were comparable with those of rosuvastatin and valsartan administered individually, suggesting that their individual pharmacokinetics were not affected by their coadministration. No dose adjustment was required and the results are supportive of a study in a larger patient population.

Lack of the effect of lobeglitazone, a peroxisome proliferator-activated receptor-γ agonist, on the pharmacokinetics and pharmacodynamics of warfarin

Aims

Lobeglitazone has been developed for the treatment of type 2 diabetes mellitus. This study was conducted to evaluate potential drug–drug interactions between lobeglitazone and warfarin, an anticoagulant with a narrow therapeutic index.

Methods

In this open-label, three-treatment, crossover study, 24 healthy male subjects were administered lobeglitazone (0.5 mg) for 1–12 days with warfarin (25 mg) on day 5 in one period. After a washout interval, subjects were administered warfarin (25 mg) alone in the other period. Pharmacokinetics of R- and S-warfarin and lobeglitazone, as well as pharmacodynamics of warfarin, as measured by international normalized ratio (INR) and factor VII activity, were assessed.

Results

The geometric mean ratios (GMRs) and 90% confidence intervals (CIs) for area under the curve from time zero to the time of the last quantifiable concentration (AUC_last) for warfarin + lobeglitazone: warfarin alone were 1.0076 (90% CI: 0.9771, 1.0391) for R-warfarin and 0.9880 (90% CI: 0.9537, 1.0235) for S-warfarin. The maximum observed plasma concentration (C_max) values were 1.0167 (90% CI: 0.9507, 1.0872) for R-warfarin and 1.0028 (90% CI: 0.9518, 1.0992) for S-warfarin, both of which were contained in the interval 0.80–1.25. Lobeglitazone had no effect on the area under the effect–time curve from time 0 to 168 hours (AUEC) of INR and factor VII activity, as demonstrated by the GMRs of 1.0091 (90% CI: 0.9872, 1.0314) and 0.9355 (90% CI: 0.9028, 0.9695), respectively. In addition, the pharmacokinetics of lobeglitazone was also unaffected by warfarin.

Conclusion

Concomitant administration of lobeglitazone and warfarin was well tolerated. Lobeglitazone had no meaningful effect on the pharmacokinetics or pharmacodynamics of warfarin. These findings indicate that lobeglitazone and warfarin can be coadministered without dosage adjustments for either drug.

Bioequivalence study of two imatinib formulations after single-dose administration in healthy Korean male volunteers

Imatinib mesylate is effective for chronic myeloid leukaemia and gastrointestinal tumours. We aimed to evaluate the pharmacokinetics of a 200-mg imatinib tablet compared to 2×100-mg imatinib tablets in order to meet the regulatory requirements for marketing in Korea.An open-label, randomized, single-dose, 2-period, 2-treatment cross-over study was conducted in 28 healthy Korean male volunteers. Subjects were administered a 200-mg imatinib tablet and 2×100-mg imatinib tablets under a fasting state according to a randomly assigned order with a 2-week wash-out period. Serial blood samples were collected up to 72 h post-dose. The pharmacokinetic parameters were calculated using non-compartmental methods.A total of 28 subjects were enrolled and 23 subjects completed the study. There were no serious adverse events during the study. 23 mild to moderate adverse events were reported (11 events with 200-mg imatinib vs. 12 events with 2×100-mg imatinib) and subjects recovered without sequelae. The Cmax value was 922.8±318.8 μg/L at 3.15 h for 200-mg imatinib tablet, and 986.3±266.0 μg/L at 2.91 h for the 2×100-mg imatinib tablet. The AUClast of 200-mg and 2×100-mg tablets were 13 084.3±39.1 and 14 131.7±3 826.2 h · μg/L, respectively. The geometric mean ratios (90% confidence intervals) for Cmax and AUClast were 0.9121 (0.8188, 1.0161) and 0.9558 (0.8685, 1.0519), respectively.A newly developed 200-mg imatinib tablet was bioequivalent to 2×100-mg imatinib tablets in healthy Korean subjects. A single-dose of either of the 2 formulations was generally well tolerated.

Effect of food on the pharmacokinetic properties of the oral sarpogrelate hydrochloride controlled-release tablet in healthy male Korean subjects

BACKGROUND

A new controlled-release formulation of sarpogrelate, a 5-hydroxytryptamine receptor subtype 2 antagonist that blocks serotonin-induced platelet aggregation, has been developed for once-daily administration.

OBJECTIVE

This study evaluated the effect of food on the pharmacokinetic properties of controlled-release sarpogrelate (sarpogrelate CR) in healthy volunteers.

METHODS

A randomized, open-label, two-period, two-treatment crossover study was performed in healthy male Korean subjects. Following an overnight fast, a single dose of sarpogrelate CR 300 mg was administered either in the fasted condition or immediately after a high-fat breakfast. Pharmacokinetic parameters were calculated using a noncompartmental analysis. Tolerability was determined using clinical laboratory testing and physical examination, including vital sign measurements, electrocardiography, and interviews with the volunteers regarding adverse events (AEs).

RESULTS

A total of 24 healthy subjects were enrolled, 23 of whom completed the study (mean [range] age, 26 years [21-45]; weight, 68.1 kg [56.0-79.9]; body mass index, 22.1 kg/m(2) [18.8-25.0]). Sarpogrelate C(max) and AUC(last) were decreased In the fed condition compared with those in the fasted condition, with geometric mean ratios (90% CI) of 0.4868 (0.4041-0.5864) and 0.7394 (0.6809-0.8028), respectively. T(max) was delayed from 0.75 to 4.0 hours after a high-fat meal, but the fed condition exhibited a similar elimination profile to that of the fasted condition. The most commonly reported AE was headache (n = 2), and other AEs were reported in 1 subject each. All of the AEs were considered mild in intensity, and the participants recovered without treatment.

CONCLUSIONS

Compared with the administration of sarpogrelate CR 300 mg in the fasted condition, administration with food was associated with a decreased rate and extent of absorption, as assessed by C(max) and AUC(last), respectively. The drug was well-tolerated by the healthy subjects in this study.

Pharmacokinetics of a new once-daily controlled-release sarpogrelate hydrochloride compared with immediate-release formulation and the effect of food

WHAT IS KNOWN AND OBJECTIVE

Sarpogrelate is a selective 5-hydroxytryptamine receptor subtype 2A antagonist that inhibits platelet aggregation and vasoconstriction. The aim of this study was to compare the pharmacokinetics of a sarpogrelate controlled-release formulation (CR) with those of the immediate-release formulation (IR). The effect of food on the pharmacokinetics of CR sarpogrelate was also evaluated.

METHODS

A randomized, open-label, 3-period, 3-treatment crossover study was conducted in 50 healthy male subjects. Subjects were allocated into one of six sequence groups. In one period, a 100-mg IR formulation was administered three times at 6-h intervals, and in the other two periods, a 300-mg CR formulation was administered once to fasting and once to fed subjects. Each period was separated by a 7-day washout period. Serial blood samples were collected up to 24 h after the first drug administration in each period. The plasma concentrations of sarpogrelate were analysed by liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated by non-compartmental methods.

RESULTS AND DISCUSSION

After the administration of the IR formulation, the plasma concentration reached a peak at 0·48 h and the drug was eliminated with a half-life (t1/2 ) of 0·7 h. After administration of the CR formulation, the plasma concentration reached a peak at 0·5 h and the drug was eliminated with a t1/2 of 3·23 h. The geometric mean ratios (CR/IR) for sarpogrelate area under the plasma concentration-time curve (AUC) and the maximum plasma drug concentration (Cmax) were 1·2040 (90% confidence interval (CI): 1·0992-1·3188) and 0·9462 (90% CI: 0·8504-1·0529). When CR was administered to fed subjects, the time to peak concentration was prolonged to 3·97 h and t1/2 was shortened to 1·45 h. The geometric mean ratios (fasting/fed) for sarpogrelate AUC and Cmax were 0·8573 (90% CI: 0·7687-0·9561) and 0·6452 (90% CI: 0·5671-0·7341).

WHAT IS NEW AND CONCLUSION

After the administration of CR and IR formulations of the same daily dose of sarpogrelate hydrochloride, the overall systemic exposure was slightly higher for the CR than for the IR formulation, whereas peak concentration was comparable between the two formulations. Food reduced the bioavailability of sarpogrelate CR.

Additive postprandial glucose-lowering effects of mitiglinide and sitagliptin in patients with type 2 diabetes mellitus

INTRODUCTION

The aim of this research was to compare the pharmacodynamics of the combination of mitiglinide and sitagliptin to that of each agent alone in Korean patients with type 2 diabetes mellitus (T2DM).

METHODS

Patients with T2DM received mitiglinide alone, sitagliptin alone, or both drugs together in randomized sequence. A meal tolerance test (MTT) was conducted for each group, and plasma concentrations of glucose, insulin, C-peptide, glucagon, and intact glucagon-like peptide-1, and dipeptidyl peptidase-4 activity were measured from 2 h before breakfast through 4 h after breakfast on day 0 (pretreatment) and day 1 (posttreatment) of each treatment period. Integrated values of these pharmacodynamic variables were analyzed for changes from pretreatment to posttreatment and for differences between the three treatment groups.

RESULTS

Twenty-six patients with glycated hemoglobin A1c level of 7.4% ± 0.6%, fasting plasma glucose concentration of 141 ± 22 mg/dL, postprandial plasma glucose (PPG) concentration of 264 ± 48 mg/dL 1 h after the MTT, and diabetes duration of 3.0 ± 3.1 years (mean ± SD) were included in the study. Compared with mitiglinide or sitagliptin alone, the combination treatment lowered PPG additively (P < 0.001 vs. mitiglinide or sitagliptin alone) and the insulin secretory response (P = 0.03 vs. mitiglinide or sitagliptin alone). The integrated insulin concentrations changed significantly from before to after treatment (P < 0.01), but the change did not differ between the combination and mitiglinide groups. The insulinogenic index increased significantly after the combination treatment (P < 0.001 vs. mitiglinide or sitagliptin alone). The combination of mitiglinide and sitagliptin was generally well tolerated, with no hypoglycemic events.

CONCLUSIONS

The combination of mitiglinide and sitagliptin did not trigger hypoglycemia and controlled postprandial glucose excursion more effectively compared with either drug alone.

Asthma and antibodies to pneumococcal virulence proteins

PURPOSE

We previously reported that asthmatics had lower anti-serotype-specific pneumococcal polysaccharide antibody levels than non-asthmatics, and the T-helper 2 (Th2) immune profile was associated with suboptimal pneumococcal polysaccharide antibody. Our objective was to determine the influence of asthma status on anti-pneumococcal protein antigen antibody levels.

METHODS

We conducted a cross-sectional study, which enrolled 16 children and adults with asthma and 14 subjects without asthma. Asthma was ascertained by predetermined criteria. Serum IgG antibody levels to pneumococcal surface protein A (PspA), pneumococcal surface protein C (PspC), pneumococcal choline-binding protein A (PcpA), and pneumolysin (PLY) were measured by enzyme-linked immunosorbent assays (ELISA). These antibody levels were compared between asthmatics and non-asthmatics. The Th2 immune profile was determined by IL-5 secretion from PBMCs cultured with house dust mite (HDM) and staphylococcal enterotoxin B (SEB) at day 7. The correlation between the anti-pneumococcal antibody levels and the Th2-HDM and SEB-responsive immune profile was assessed.

RESULTS

Of the 30 subjects, 16 (53%) were male and the median age was 26 years. There were no significant differences in anti-PspA, anti-PspC, anti-PcpA, and anti-PLY antibody levels between asthmatics and non-asthmatics. The Th2 immune profile was inversely correlated with the anti-PspC antibody levels (r = -0.53, p = 0.003). This correlation was significantly modified by asthma status (r = -0.74, p = 0.001 for asthmatics vs. r = -0.06, p = 0.83 for non-asthmatics). Other pneumococcal protein antibodies were not correlated with the Th2 immune profile.

CONCLUSION

No significant differences in the anti-pneumococcal protein antigen antibody levels between asthmatics and non-asthmatics were found. Asthma status is an important effect modifier determining the negative influence of the Th2 immune profile on anti-PspC antibody levels.

Evaluation of pharmacokinetic and pharmacodynamic profiles and tolerability after single (2.5, 5, or 10 mg) and repeated (2.5, 5, or 10 mg bid for 4.5 days) oral administration of ivabradine in healthy male Korean volunteers

BACKGROUND

Ivabradine, a selective inhibitor of the pacemaker current in the sinoatrial node, has shown pure heart rate (HR)-reducing effects with anti-ischemic efficacy as well as improvement in heart failure outcomes.

OBJECTIVE

The purpose of this study was to explore pharmacokinetic (PK) and pharmacodynamic (PD) characteristics and tolerability in healthy male Korean volunteers, as well as to compare them with PK/PD profiles of white subjects.

METHODS

This was a randomized, double-blind, placebo-controlled Phase I study conducted in healthy male subjects. For each of the 3 dosing groups, 9 subjects were randomized to receive ivabradine and 3 to receive placebo. Subjects received a single oral dose of ivabradine 2.5, 5, or 10 mg and after a 3-day washout period, repeat doses of 2.5, 5, or 10 mg BID for 4.5 days. Blood and urine samples were collected over 72 hours during each period, and levels of ivabradine and its metabolite S18982 were determined by using validated LC-MS/MS, followed by noncompartmental PK analysis. For PD properties and tolerability, 24-hour Holter recordings were obtained: at baseline, after a single dose, after repeated doses, and after the last dose. Serial resting 12-lead ECG assessments were also performed throughout the study.

RESULTS

Forty-eight subjects were enrolled, and 45 completed the study. After single doses of 2.5, 5, and 10 mg, respective mean Cmax levels of ivabradine were 9, 15, and 39 ng/mL, and mean AUC0-last values were 30, 52, and 121 ng h/mL. At steady state, mean Cmax,ss levels were 11, 19, and 42 ng/mL, reached at a median Tmax of 0.67 hour for all 3 doses. The mean AUC0-τ levels were 43, 58, and 139 ng h/mL, respectively. The PK findings were linear with dose and time. Decreases in mean HR on both the Holter recordings and ECGs were observed in all of the ivabradine groups compared with placebo. After the repeated doses, mean decreases in HR were greater than those for the single doses for the same period. Statistically significant differences were observed between the 5- and 10-mg ivabradine groups and placebo. A total of 3 adverse events were reported in 2 subjects receiving ivabradine; both fully recovered without sequelae.

CONCLUSIONS

Single and repeated administration of ivabradine were generally well tolerated in these healthy male Korean volunteers. Ivabradine induced significant reductions in HR, especially at doses of 5 and 10 mg. PK/PD characteristics were similar to those found in white subjects, suggesting that the dose concentration-response relationship of ivabradine is similar between Korean and white subjects.

A simple dosing scheme for intravenous busulfan based on retrospective population pharmacokinetic analysis in korean patients

Busulfan is an antineoplastic agent with a narrow therapeutic window. A post-hoc population pharmacokinetic analysis of a prospective randomized trial for comparison of four-times daily versus once-daily intravenous busulfan was carried out to search for predictive factors of intravenous busulfan (iBu) pharmacokinetics (PK). In this study the population PK of iBu was characterized to provide suitable dosing recommendations. Patients were randomized to receive iBu, either as 0.8 mg/kg every 6 h or 3.2 mg/kg daily over 4 days prior to hematopoietic stem cell transplantation. In total, 295 busulfan concentrations were analyzed with NONMEM. Actual body weight and sex were significant covariates affecting the PK of iBu. Sixty patients were included in the study (all Korean; 23 women, 37 men; mean [SD] age, 36.5 [10.9] years; weight, 66.5 [11.3] kg). Population estimates for a typical patient weighing 65 kg were: clearance (CL) 7.6 l/h and volume of distribution (V_d) 32.2 l for men and 29.1 L for women. Inter-individual random variabilities of CL and V_d were 16% and 9%. Based on a CL estimate from the final PK model, a simple dosage scheme to achieve the target AUC_0-inf (defined as median AUC_0-inf with a once-daily dosage) of 26.18 mg/l·hr, was proposed: 24.79·ABW^0.5 mg q24h, where ABW represents the actual body weight in kilograms. The dosing scheme reduced the unexplained interindividual variabilities of CL and Vd of iBu with ABW being a significant covariate affecting clearance of iBU. We propose a new simple dosing scheme for iBu based only on ABW.

Pharmacokinetic interaction between pitavastatin and valsartan: a randomized, open-labeled crossover study in healthy male Korean volunteers

BACKGROUND

Pitavastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, and valsartan, an angiotensin receptor blocker, are used concurrently in some patients who are both hyperlipidemic and hypertensive. However, to date, no published studies have explored whether there is an interaction between pitavastatin and valsartan.

OBJECTIVE

The aim of this study was to investigate the potential pharmacokinetic interaction between pitavastatin and valsartan in healthy male volunteers in Korea.

METHODS

A randomized, open-label crossover study was conducted in healthy male Korean volunteers. In varying sequences, each subject received pitavastatin 2 × 2 mg, valsartan 2 × 160 mg, and both treatments, once daily for 7 consecutive days, with a 7-day washout period between each treatment period. Plasma samples were obtained at steady state for the pharmacokinetic evaluation of pitavastatin and valsartan. Pharmacodynamic assessment included lipid profiles and vital sign measurements (systolic and diastolic blood pressure [SBP and DBP, respectively] and pulse rate [PR]). A safety profile assessment, which included vital sign measurements, ECG, and clinical laboratory testing, was performed in each subject.

RESULTS

A total of 24 subjects were enrolled (mean age, 30.5 years [range, 23.0-45.0 years]; mean body weight, 71.2 kg [range, 56.1-86.0 kg]; and mean body mass index, 23.2 kg/m(2) [range, 19.2-25.8 kg/m(2)]). The 95% CIs of the geometric mean ratios of AUC(τ) and C(max,ss) of pitavastatin were 0.97 to 1.11 and 0.73 to 1.09, respectively. The 95% CIs of the geometric mean ratios of AUC(τ) and C(max,ss) of valsartan were 0.90 to 1.27 and 0.81 to 1.29. Pitavastatin administered as monotherapy and in combination with valsartan was associated with significantly lowered total cholesterol and LDL-C compared with valsartan monotherapy (both, P < 0.05). Differences in lipid-lowering effects were not statistically significant between pitavastatin monotherapy and pitavastatin combined with valsartan. Valsartan monotherapy and valsartan combined with pitavastatin were associated with significantly lower SBP and DBP compared with baseline (both, P < 0.05), although no significant changes in PR were observed. No significant differences in BP or PR changes were noted between concurrent administration of valsartan monotherapy compared with pitavastatin + valsartan. There were no serious AEs reported, and none of the subjects discontinued the study due to AEs.

CONCLUSIONS

The pharmacokinetic profiles of pitavastatin and valsartan administered as monotherapy were comparable to combination treatment in these healthy male Korean volunteers, suggesting that individual pharmacokinetic properties are not significantly affected by concurrent administration. The concurrent administration of pitavastatin and valsartan was generally well tolerated. The findings from the present study provide a basis for a larger study in hypertensive patients with hyperlipidemia.

Ganglioneuroblastoma presenting as dilated cardiomyopathy

We report an unusual presentation of ganglioneuroblastoma with features of dilated cardiomyopathy in a 22 month old girl. She was admitted with cardiomegaly; during echocardiography a suspicious abdominal mass was detected by chance. Further imaging studies, including abdominal ultrasonography and spiral computed tomography, revealed a solid mass originating in the right adrenal gland. Metabolic studies and pathological findings were compatible with ganglioneuroblastoma. Following tumour removal and supportive therapy for cardiomyopathy, her clinical condition and laboratory findings improved. Although ganglioneuroblastoma with features of dilated cardiomyopathy is rare, because neurogenic tumours may be involved in its development, measurement of catecholamines in children with dilated cardiomyopathy is strongly recommended.

Effect of SKI 306X, a new herbal anti-arthritic agent, in patients with osteoarthritis of the knee: a double-blind placebo controlled study

SKI 306X is a purified extract from a mixture of three oriental herbal medicines (Clematis mandshurica, Trichosanthes kirilowii and Prunella vulgaris) that have been widely used for the treatment of inflammatory diseases such as lymphadenitis and arthritis in far East Asia. A double-blind, controlled study was performed to evaluate the efficacy and safety of SKI 306X with placebo in 96 patients with classical osteoarthritis of the knee. Patients were randomized to four treatment groups: placebo, 200 mg, 400 mg and 600 mg of SKI 306X t.i.d.. Clinical efficacy and safety were evaluated for 4 weeks continuous treatment. SKI 306X demonstrated its clinical efficacy, as assessed by 100 mm visual analogue scale (VAS), Lequesne index and patients' and investigators opinion of the therapeutic effect compared with placebo (p<0.01). No significant adverse events were observed in patients treated with SKI 306X. This study demonstrated that SKI 306X, a new herbal anti-arthritic agent provided clinical efficacy in patients with osteoarthritis.

Salviae radix root extract inhibits immunoglobulin E-mediated allergic reaction

We investigated the effects of the aqueous extract of Salviae radix root (SRRAE) on immediate allergic reactions. SRRAE inhibited by 72.7% passive cutaneous anaphylaxis activated by anti-dinitrophenyl (DNP) immunoglobulin E (IgE). SRRAE dose dependently inhibited histamine release and tumor necrosis factor-alpha production from the rat peritoneal mast cells (RPMCs) by anti-DNP IgE. However, SRRAE showed no significant inhibitory effect on compound 48/80-induced systemic allergic reaction and histamine release from RPMCs. The level of cAMP in RPMCs, when SRRAE was added, significantly increased compared with that of a normal control. These results indicate that SRRAE may contain compounds with actions that inhibit anti-DNP IgE-induced mast cell degranulation in rats.

Rapid purification and characterization of nucleoside diphosphate kinase isoforms using ATP-sepharose affinity column chromatography

Nucleoside diphosphate kinases (NDP kinases), products of the nm23 gene, catalyze the transfer of the terminal phosphate group of the nucleoside triphosphate to the corresponding diphosphate and may be involved in tumor metastasis suppression, development, and signal transduction. NDP kinase from various sources including human erythrocytes, rat brain tissue and E. coli strain BL21 transformed with pET3C expression plasmids containing nm23-H1 or nm23-H2, were purified in one step to homogeneity using ATP-sepharose affinity column chromatography. This method was applicable for the purification of various NDP kinases which show the same enzymatic activity and immunodetection, but have various molecular weight and quaternary structures.