Pharmacokinetic and pharmacodynamic drug-drug interactions between evogliptin and empagliflozin or dapagliflozin in healthy male volunteers.

Evogliptin (EV) is a novel dipeptidyl peptidase-4 inhibitor (DPP4i) for glycemic control in patients with type 2 diabetes mellitus (T2DM). This study evaluated the pharmacokinetic (PK) and pharmacodynamic (PD) interactions between EV and sodium glucose cotransporter-2 inhibitors (SGLT2i) in healthy volunteers since combination therapy of DPP4i and SGLT2i has been considered as an effective option for T2DM treatment. A randomized, open-label, multiple-dose, two-arm, three-period, three treatments, two-sequence crossover study was conducted in healthy Korean volunteers. In arm 1, subjects were administered 5 mg of EV once daily for 7 days, 25 mg of empagliflozin (EP) once daily for 5 days, and the combination once daily for 5 days (EV + EP). In arm 2, subjects were administered 5 mg of EV once daily for 7 days, 10 mg of dapagliflozin (DP) once daily for 5 days, and the combination once daily for 5 days (EV + DP). Serial blood samples were collected for PK analysis, and oral glucose tolerance tests were conducted for PD analysis. In each arm, a total of 18 subjects completed the study. All adverse events (AEs) were mild with no serious AEs. The geometric mean ratio and confidence interval of the main PK parameters (maximum concentration of the drug in plasma at steady state and area under the plasma drug concentration-time curve within a dosing interval at a steady state) between EV and either EP or DP alone were not significantly altered by co-administration. Administration of EV + EP or EV + DP did not result in significant PD changes, as determined by the glucose-lowering effect. Administration of EV + EP or EV + DP had no significant effects on the PK profiles of each drug. All treatments were well-tolerated.

Evaluation of pharmacokinetic interactions between lobeglitazone, empagliflozin, and metformin in healthy subjects.

Concomitant administration of lobeglitazone, empagliflozin, and metformin is expected to enhance blood glucose-lowering effects and improve medication compliance in patients with diabetes mellitus. In this study, we investigated the pharmacokinetic (PK) interactions and safety of lobeglitazone and co-administered empagliflozin and metformin, which are approved agents used in clinical settings. Two randomized, open-label, multiple-dose, 2-treatment, 2-period, 2-sequence crossover clinical trials (parts 1 and 2) were conducted independently. In part 1, lobeglitazone monotherapy or lobeglitazone, empagliflozin, and metformin triple therapy was administered for 5 days. In part 2, empagliflozin and metformin dual therapy or the abovementioned triple therapy were administered for 5 days. Serial blood samples were collected up to 24 hours after the last dose in each period for PK evaluation. The primary PK parameters (AUCtau,ss, Cmax,ss) of treatment regimens in each study part were calculated and compared. For lobeglitazone, the geometric mean ratios (GMRs) with 90% confidence intervals (CI) for triple therapy over monotherapy were 1.08 (1.03-1.14) for Cmax,ss and 0.98 (0.90-1.07) for AUCtau,ss. For empagliflozin, the GMRs and 90% CIs for triple therapy over dual therapy were 0.87 (0.78-0.97) for Cmax,ss and 0.97 (0.93-1.00) for AUCtau,ss. For metformin, the GMRs and 90% CIs for triple therapy over dual therapy were 1.06 (0.95-1.17) for Cmax,ss and 1.04 (0.97-1.12) for AUCtau,ss. All reported adverse events were mild. The triple therapy consisting of lobeglitazone, empagliflozin, and metformin did not show any clinically relevant drug interactions in relation to the PKs and safety of each drug substance. Trial Registration: ClinicalTrials.gov Identifier: NCT04334213.

Pharmacokinetics and safety of evogliptin in hepatically impaired patients.

AIMS: Evogliptin is a potent and selective dipeptidyl peptidase-4 inhibitor for glycaemic control in patients with type 2 diabetes mellitus. Since evogliptin is mainly eliminated through hepatic metabolism, we investigated the pharmacokinetics (PKs) and safety characteristics of evogliptin in Korean patients with mild or moderate hepatic impairment. METHODS: An open-label, parallel-group study was conducted in patients with mild or moderate hepatic impairment and healthy control subjects matched to each patient for sex, age and body mass index. A single dose (5 mg) of evogliptin was administered orally, and serial blood samples were collected over 120 h to assess the PK profile of evogliptin and its main metabolites (M7 and M8). RESULTS: Patients with mild hepatic impairment and their matched healthy controls showed similar maximum concentration (Cmax ) and area under the concentration-time curve values from 0 to 120 h (AUClast ); the geometric mean ratio (GMR) and 90% confidence interval (CI) were 1.04 (0.80, 1.35) and 1.01 (0.90, 1.14), respectively. Exposure to evogliptin (Cmax and AUClast ) was increased by about 40% in patients with moderate hepatic impairment-the GMR and 90% CI were 1.37 (1.09, 1.72) and 1.44 (1.18, 1.75), respectively. The metabolic ratios of M7 and M8 were lower in patients with moderate hepatic impairment than in matched healthy controls. Evogliptin was well tolerated by both patients and healthy subjects. CONCLUSION: Although evogliptin exposure was increased in patients with moderate hepatic impairment, the increase is unlikely to affect safety and efficacy adversely, and no dose adjustment is warranted.

Evaluation of pharmacokinetic interactions between amoxicillin, clarithromycin, and the potassium-competitive acid blocker YH4808 in healthy subjects.

YH4808 is a novel potassium-competitive acid blocker that was developed as a therapeutic agent for gastric acid-related diseases; it may replace proton pump inhibitors, which are widely used in combination with amoxicillin and clarithromycin for Helicobacter pylori eradication. We compared the pharmacokinetic (PK) profiles and safety of amoxicillin, clarithromycin, and YH4808 used as monotherapies or in combination for evaluating potential drug interactions. An open-label, randomized, single-dose, Latin-square (4 × 4) crossover study was conducted in 32 healthy Korean volunteers. Subjects were randomly assigned to one of the 4 treatment sequences that consisted of 4 periods separated by 21-day washout intervals. PK parameters of YH4808, amoxicillin and clarithromycin administered in combination were compared with those of the respective monotherapies. The geometric mean ratios of the maximum concentration (Cmax) and the area under the time-concentration curve from time zero to time of the last quantifiable concentration (AUClast) of YH4808 increased during the triple therapy by 48.6% and 29.1%, respectively. Similarly, the Cmax and AUClast of M3 (active metabolite of YH4808) increased by 23.3% and 16.0%, respectively. The Cmax and AUClast of clarithromycin increased by 27.4% and 30.5%, and those of 14-hydroxyclarithromycin were increased by 23.1% and 32.4%, respectively. The corresponding amoxicillin values decreased during the triple therapy by 21.5% and 15.6%, respectively. There was no clinically significant change in safety assessment related to either monotherapies or triple therapy. In conclusion, amoxicillin, clarithromycin and YH4808 administered as triple therapy did not exhibit significant PK interactions and were not associated with safety issues. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01921647.

Efficacy of Lenvervimab, a Recombinant Human Immunoglobulin, in Treatment of Chronic Hepatitis B Virus Infection.

The mechanism of action of hepatitis B immunoglobulin (HBIG) for chronic hepatitis B (CHB) treatment is not fully understood. A clinical trial in Japan suggested that HBIG therapy might benefit patients with CHB.1 Lenvervimab, a recombinant monoclonal HBIG developed by GC Pharma (Yongin, South Korea), has been screened from an anti-HBs-enriched phage-display library cloned from hepatitis B vaccine-boosted human blood cells and was produced in Chinese hamster ovary cells.2-4.

The safety, pharmacodynamics, and pharmacokinetics of immediate-release formulation containing esomeprazole 20 mg/sodium bicarbonate 800 mg in healthy adult male.

BACKGROUND: Esomeprazole is the most effective treatment for acid-related disorders and is widely used with enteric coating due to rapid degradation in the acidic environment. However, the enteric-coated formulation delays absorption and onset of action. To overcome this limitation, an immediate-release formulation containing esomeprazole 20 mg and sodium bicarbonate 800 mg (IR-ESO) was developed. PURPOSE: To evaluate the safety, pharmacokinetics (PK), and pharmacodynamics of IR-ESO compared to those of esomeprazole 20 mg (ESO). METHODS: A randomized, open-label, multiple-dose, two-treatment, two-sequence crossover study was conducted in 40 healthy male subjects. Subjects received either IR-ESO or ESO for 7 days. After single and multiple dosing, blood samples were collected for PK analysis, and intragastric pH was assessed by 24-hr pH monitoring. RESULTS: Plasma esomeprazole exposure of IR-ESO was similar to that of ESO after single and multiple dosing. Time to peak concentration of IR-ESO (0.50-0.75 hr) was shorter than that of ESO (1.25-1.50 hr). Percentage changes in 24-hr integrated gastric acidity from baseline for IR-ESO were similar to those for ESO. In addition, mean time to maintain gastric pH >4 for 24 hr was similar for both drugs (IR-ESO 55.5-69.9% vs ESO 56.8-70.2%). Evaluation of time to first reach pH 4 after dosing indicated that IR-ESO showed a faster onset than ESO. All subjects found the drug tolerable, and there were no significant differences in adverse events between two drugs. CONCLUSION: This study showed that IR-ESO produced a rapid, safe and sustained gastric acid suppression (ClinicalTrials.gov: NCT03211143).

Comparison of the Pharmacokinetic-Pharmacodynamic Relationships of Two Darbepoetin Alfa Formulations in Healthy Male Volunteers.

OBJECTIVE: This study compared the pharmacokinetic (PK), pharmacodynamic (PD), and safety properties of the test (CJ-40001) and reference (NESP®) versions of darbepoetin alfa following a single subcutaneous (SC) or intravenous (IV) administration in healthy male subjects. METHODS: A single-blind, randomized, single-dose, two-period, two-intervention crossover study was conducted, with two separate parts consisting of SC or IV administration. In each period, either a test or reference product was administered via the SC or IV route. Serial blood samples for PK analysis and the reticulocyte, hematocrit, hemoglobin, and red blood cell counts for PD analysis were collected for up to 360 or 264 h after SC or IV administration, respectively. The PK and PD parameters were calculated using non-compartmental methods. The 90% confidence intervals of the geometric mean ratios for the PK and PD parameters between the two interventions were estimated. Safety and anti-drug antibody profile assessments were performed. RESULTS: The mean darbepoetin alfa concentration-time profiles were comparable between the two products for SC and IV administration. Additionally, the PD and safety profiles were similar between the two products. Anti-drug antibody reactivity was negative for all samples from both intervention groups for SC and IV administration. The time-matched serum darbepoetin alfa concentration and the PD markers presented a counter-clockwise hysteresis, which suggests a time delay between the exposure and response. CONCLUSION: The test and reference darbepoetin alfa formulations had similar PK, PD, and safety profiles. Thus, it is expected that the two formulations are able to be used interchangeably in clinical settings. ClinicalTrials.gov Identifier: NCT03542916.

Comparison of biosimilar filgrastim with a reference product: pharmacokinetics, pharmacodynamics, and safety profiles in healthy volunteers.

PURPOSE: Filgrastim, a granulocyte-colony stimulating factor, is used to treat patients with neutropenia, including neutropenic fever. Leucostim® is a recombinant filgrastim product tested for biosimilarity with its reference product, Neupogen®. We conducted a comparative clinical trial of the 2 products. PATIENTS AND METHODS: A randomized, open-label, 2-way crossover, single-dose Phase I study was conducted for 56 healthy subjects. After a 5 and 10 µg/kg single subcutaneous administration of test and reference product, pharmacokinetic and pharmacodynamic parameters (absolute neutrophil count and CD34+ cell count) were compared. During the study, safety tests and adverse event monitoring were performed. RESULTS: The test and the reference products had a comparable pharmacokinetic, pharmacodynamic, and safety profile. In both 5 and 10 µg/kg dosing, the 90% CIs of the test to reference ratio for primary parameters (peak plasma concentration and area under the plasma concentration vs time curve from time 0 extrapolated to the infinite time for plasma filgrastim concentration; maximal effect and area under the time-effect curve from time 0 to time of the last quantifiable effect for absolute neutrophil count) were within the 0.8-1.25 range. In addition, safety profiles between the 2 products were similar without any serious adverse events. CONCLUSION: This study has provided firm clinical evidence that the test filgrastim product is similar to its reference filgrastim product.

Physiologically-based pharmacokinetic predictions of intestinal BCRP-mediated drug interactions of rosuvastatin in Koreans.

It was recently reported that the Cmax and AUC of rosuvastatin increases when it is coadministered with telmisartan and cyclosporine. Rosuvastatin is known to be a substrate of OATP1B1, OATP1B3, NTCP, and BCRP transporters. The aim of this study was to explore the mechanism of the interactions between rosuvastatin and two perpetrators, telmisartan and cyclosporine. Published (cyclosporine) or newly developed (telmisartan) PBPK models were used to this end. The rosuvastatin model in Simcyp (version 15)'s drug library was modified to reflect racial differences in rosuvastatin exposure. In the telmisartan-rosuvastatin case, simulated rosuvastatin CmaxI/Cmax and AUCI/AUC (with/without telmisartan) ratios were 1.92 and 1.14, respectively, and the Tmax changed from 3.35 h to 1.40 h with coadministration of telmisartan, which were consistent with the aforementioned report (CmaxI/Cmax: 2.01, AUCI/AUC:1.18, Tmax: 5 h → 0.75 h). In the next case of cyclosporine-rosuvastatin, the simulated rosuvastatin CmaxI/Cmax and AUCI/AUC (with/without cyclosporine) ratios were 3.29 and 1.30, respectively. The decrease in the CLint,BCRP,intestine of rosuvastatin by telmisartan and cyclosporine in the PBPK model was pivotal to reproducing this finding in Simcyp. Our PBPK model demonstrated that the major causes of increase in rosuvastatin exposure are mediated by intestinal BCRP (rosuvastatin-telmisartan interaction) or by both of BCRP and OATP1B1/3 (rosuvastatin-cyclosporine interaction).

Population pharmacokinetics of remifentanil in critically ill patients receiving extracorporeal membrane oxygenation.

Extracorporeal membrane oxygenation (ECMO) is associated with pharmacokinetic (PK) changes of drugs. It presents considerable challenges to providing optimal dosing regimens for patients receiving ECMO. We aimed to describe the population PK of remifentanil in critically ill adult patients receiving venoartrial extracorporeal membrane oxygenation (VA-ECMO) and to identify determinants associated with altered remifentanil concentrations. The population PK model of remifentanil was developed using nonlinear mixed effects modelling (NONMEM). Fifteen adult patients who received a continuous infusion of remifentanil during VA-ECMO participated in the study. The PK of remifentanil was best described by a one-compartment model with additive and proportional residual errors. Remifentanil concentrations were affected by sex and ECMO pump speed. The final PK model included the effect of sex and ECMO pump speed on clearance is developed as followed: clearance (L/h) = 366 × 0.502sex × (ECMO pump speed/2350)2.04 and volume (L) = 41. Remifentanil volume and clearance were increased in adult patients on VA-ECMO compared with previously reported patients not on ECMO. We suggest that clinicians should consider an increased remifentanil dosing to achieve the desired level of sedation and provide a dosing regimen according to sex and ECMO pump speed.

Bortezomib pharmacokinetics in tumor response and peripheral neuropathy in multiple myeloma patients receiving bortezomib-containing therapy.

The usefulness of pharmacokinetics of bortezomib for multiple myeloma (MM) with respect to the maximum response to bortezomib and bortezomib-induced peripheral neuropathy (BIPN) development was studied. Maximum response to subcutaneous bortezomib therapy and BIPN occurrence for the first 12 weeks of treatment in 35 MM patients treated by bortezomib-dexamethasone (VD) and bortezomib-melphalan-prednisone (VMP) were evaluated. On day 1 of cycle 1, seven whole-blood samples were collected for 3 h after dosing completion to obtain the maximum plasma concentration and area under the time-concentration curve during 3 h postdose (AUC0-3) in each patient. A total of 35 patients with complete data were analyzed and the overall response rate was 91.4%. Complete response (CR) was observed in 42.9% patients. The maximum plasma concentration (Cmax) was significant for the CR rate in two different models [full model: odds ratio (OR)=1.092; P=0.038, final model: OR=1.081; P=0.038]. In addition, Cmax was associated with a progression-free survival advantage. Overall, 48.6% of patients developed BIPN including peripheral sensory neuropathy and neuralgia. The VMP-treated patients had a higher risk compared with the VD-treated patients (OR=21.662; P=0.029). Cmax had a tendency to affect the occurrence of BIPN (≥grade 2) (OR=1.064; P=0.092). In real-world clinical practice using bortezomib for MM patients, Cmax among pharmacokinetic factors significantly affected the achievement of CR. The VMP-treated patients showed vulnerability to BIPN, suggesting the necessity for more careful monitoring.

Decreased potency of fimasartan in liver cirrhosis was quantified using mixed-effects analysis.

Fimasartan is a nonpeptide angiotensin II receptor blocker. In a previous study that compared the pharmacokinetics (PK) of fimasartan between patients with hepatic impairment (cirrhosis) and healthy subjects, the exposure to fimasartan was found to be higher in patients, but the decrease of blood pressure (BP) was not clinically significant in those with moderate hepatic impairment. The aims of this study were to develop a population PK-pharmacodynamic (PD) model of fimasartan and to evaluate the effect of hepatic function on BP reduction by fimasartan using previously published data. A 2-compartment linear model with mixed zero-order absorption followed by first-order absorption with a lag time adequately described fimasartan PK, and the effect of fimasartan on BP changes was well explained by the inhibitory sigmoid function in the turnover PK-PD model overlaid with a model of circadian rhythm (NONMEM version 7.2). According to our PD model, the lower BP responses in hepatic impairment were the result of the increased fimasartan EC50 in patients, rather than from a saturation of effect. This is congruent with the reported pathophysiological change of increased plasma ACE and renin activity in hepatic cirrhosis.

Pharmacokinetic drug interaction between atorvastatin and ezetimibe in healthy Korean volunteers.

Atorvastatin and ezetimibe are frequently co-administered to treat patients with dyslipidemia for the purpose of low-density lipoprotein cholesterol control. However, pharmacokinetic (PK) drug interaction between atorvastatin and ezetimibe has not been evaluated in Korean population. The aim of this study was to investigate PK drug interaction between two drugs in healthy Korean volunteers. An open-label, randomized, multiple-dose, three-treatment, three-period, Williams design crossover study was conducted in 36 healthy male subjects. During each period, the subjects received one of the following three treatments for seven days: atorvastatin 40 mg, ezetimibe 10 mg, or a combination of both. Blood samples were collected up to 96 h after dosing, and PK parameters of atorvastatin, 2-hydroxyatorvastatin, total ezetimibe (free ezetimibe + ezetimibe-glucuronide), and free ezetimibe were estimated by non-compartmental analysis in 32 subjects who completed the study. Geometric mean ratios (GMRs) with 90% confidence intervals (CIs) of the maximum plasma concentration (Cmax,ss) and the area under the curve within a dosing interval at steady state (AUCτ,ss) of atorvastatin when administered with and without ezetimibe were 1.1087 (0.9799-1.2544) and 1.1154 (1.0079-1.2344), respectively. The corresponding values for total ezetimibe were 1.0005 (0.9227-1.0849) and 1.0176 (0.9465-1.0941). There was no clinically significant change in safety assessment related to either atorvastatin or ezetimibe. Co-administration of atorvastatin and ezetimibe showed similar PK and safety profile compared with each drug alone. The PK interaction between two drugs was not clinically significant in healthy Korean volunteers.

Retracted: Physiologically based pharmacokinetic predictions of intestinal BCRP-mediated effect of telmisartan on the pharmacokinetics of rosuvastatin in humans.

'Physiologically based pharmacokinetic predictions of intestinal BCRP-mediated effect of telmisartan on the pharmacokinetics of rosuvastatin in humans' by Soo Hyeon Bae, Wan-Su Park, Seunghoon Han, Gab-jin Park, Jongtae Lee, Taegon Hong, Sangil Jeon and Dong-Seok Yim The above article, published online on 06 February 2017 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor in Chief, K. Sandy Pang, and John Wiley & Sons, Ltd. The authors retracted the paper due to errors associated with use of log D vs. log P of telmisartan as inputs of the PBPK model. The authors concluded that there are too many changes in the article to be resolved by an Erratum, and had requested a retraction. Reference Bae, S. H., Park, W.-S., Han, S., Park, G., Lee, J., Hong, T., Jeon, S., and Yim, D.-S. (2016) Physiologically based pharmacokinetic predictions of intestinal BCRP-mediated effect of telmisartan on the pharmacokinetics of rosuvastatin in humans. Biopharm. Drug Dispos., doi: 10.1002/bdd.2060.

Use of a Target-Mediated Drug Disposition Model to Predict the Human Pharmacokinetics and Target Occupancy of GC1118, an Anti-epidermal Growth Factor Receptor Antibody.

GC1118 is an anti-epidermal growth factor receptor (EGFR) monoclonal antibody that is currently under clinical development. In this study, the pharmacokinetics (PK) of GC1118 were modelled in monkeys to predict human PK and receptor occupancy (RO) profiles. The serum concentrations of GC1118 and its comparator (cetuximab) were assessed in monkeys with a non-compartmental analysis and a target-mediated drug disposition (TMDD) model after intravenous infusion (3-25 mg/kg) of these drugs. The scaling exponent of the EGFR synthesis rate was determined using a sensitivity analysis. The human cetuximab exposures were simulated by applying different exponents (0.7-1.0) for the EGFR synthesis rate in the allometric monkey PK model. Simulated Cmax and area under the curve values therein were compared with those previously reported in the literature to find the best exponent for the EGFR synthesis rate in human beings. The TMDD model appropriately described the monkey PK profile, which showed a decrease in clearance (CL; 1.2-0.4 ml/hr/kg) as the dose increased. The exponents for CL (0.75) and volume of distribution (Vd; 1.0) were used for the allometric scaling to predict human PK. The allometric coefficient for the EGFR synthesis rate chosen by the sensitivity analysis was 0.85, and the RO profiles that could not be measured experimentally were estimated based on the predicted concentrations of the total target and the drug-target complex. Our monkey TMDD model successfully predicts human PK and RO profiles of GC1118 and can be used to determine the appropriate dose for a first-in-human study investigating this drug.

Comparison of oral absorption models for pregabalin: usefulness of transit compartment model.

Pregabalin is an anticonvulsant used for the treatment of neuropathic pain and partial seizure in adults. The aim of this study was to develop a population pharmacokinetic (PK) model to describe the absorption characteristics of pregabalin given fasted or after meals. Data from five healthy subject PK studies (n=88) of single- or multiple-dose pregabalin (150 mg) were used. Pregabalin was administered twice daily, without meals or 30 min after a meal (regular or high-fat diet) in the morning and 30 min or 4 h after a meal (regular diet) in the evening. Serial plasma samples were collected up to 24 h after the last dose for PK analysis. Because the peak concentrations were not properly modeled by a conventional first-order absorption model, Erlang frequency distribution, Weibull-type absorption, and transit compartment models were tested on a two-compartment linear PK model using a nonlinear mixed-effects method (NONMEM; version 7.3). The transit compartment model best described the absorption characteristics of pregabalin regardless of meal status. We conclude that the absorption model should be carefully chosen based on the principle of model development and validation and not by following a conventional first-order absorption model for its popularity and simplicity, especially when the PK dataset includes densely sampled absorption-phase data.

Comparative Pharmacokinetic Analysis of Thiamine and Its Phosphorylated Metabolites Administered as Multivitamin Preparations.

PURPOSE: Fursultiamine and benfotiamine are lipophilic thiamine derivatives used as oral sources of thiamine. Although there are many publications on the pharmacokinetic (PK) properties of thiamine-containing products, no direct comparisons between these agents . We aimed to compare the PK profiles of these lipophilic thiamine derivatives and to compare the extent of the increase in bioavailability to that of naïve thiamine. METHODS: Two randomized, single-dose, 2-way crossover, full PK studies were conducted in healthy Korean male subjects (n = 24 per group). Among the test compounds, fursultiamine was compared with benfotiamine (reference A in study A) and thiamine nitrate (reference B in study B). All formulations were multivitamin preparations containing the test or reference formulation as the major thiamine source. In study A, the plasma and hemolysate concentrations of thiamine and its metabolites were measured, while only the plasma thiamine concentration was assayed in study B. FINDINGS: The systemic thiamine exposure of the test compound was slightly greater than that of reference A, based on the geometric mean ratio (%) of the AUClast value for plasma (116.6%) and hemolysate (137.5%). The thiamine diphosphate (TDP) distribution between plasma and hemolysate showed clear differences according to the formulations, in that more TDP was present in the hemolysate when thiamine was given as the test formulation. The AUClast value of plasma thiamine showed a >300% increase when thiamine was given as the test formulation in study B. The summed total exposure to thiamine (thiamine + TDP in both plasma and hemolysate) observed as a point estimate after the administration of fursultiamine was slightly greater than that with benfotiamine; however, the 90% CI was within the conventional bioequivalence range. IMPLICATIONS: These findings support clear benefits of lipophilic thiamine derivatives in the absorption of thiamine in healthy volunteers. Clinical Research Information Service identifiers: KCT0001419 (study A), KCT0001628 (study B).

Immunogenicity and Safety of Trivalent Split Influenza Vaccine in Healthy Korean Adults with Low Pre-Existing Antibody Levels: An Open Phase I Trial.

PURPOSE: A phase I clinical trial was conducted to evaluate the immunogenicity and safety of newly developed egg-cultivated trivalent inactivated split influenza vaccine (TIV) in Korea. MATERIALS AND METHODS: The TIV was administered to 43 healthy male adults. Subjects with high pre-existing titers were excluded in a screening step. Immune response was measured by a hemagglutination inhibition (HI) assay. RESULTS: The seroprotection rates against A/California/7/2009 (H1N1), A/Perth/16/2009 (H3N2) and B/Brisbane/60/2009 were 74.42% [95% confidence interval (CI): 61.38-87.46], 72.09% (95% CI: 58.69-85.50), and 86.05% (95% CI: 75.69-96.40), respectively. Calculated seroconversion rates were 74.42% (95% CI: 61.38-87.46), 74.42% (95% CI: 61.38-87.46), and 79.07% (95% CI: 66.91-91.23), respectively. There were 25 episodes of solicited local adverse events in 21 subjects (47.73%), 21 episodes of solicited general adverse events in 16 subjects (36.36%) and 5 episodes of unsolicited adverse events in 5 subjects (11.36%). All adverse events were grade 1 or 2 and disappeared within three days. CONCLUSION: The immunogenicity and safety of TIV established in this phase I trial are sufficient to plan a larger scale clinical trial.

Model-based adaptive phase I trial design of post-transplant decitabine maintenance in myelodysplastic syndrome.

BACKGROUND: This report focuses on the adaptive phase I trial design aimed to find the clinically applicable dose for decitabine maintenance treatment after allogeneic hematopoietic stem cell transplantation in patients with higher-risk myelodysplastic syndrome and secondary acute myeloid leukemia. METHODS: The first cohort (three patients) was given the same initial daily dose of decitabine (5 mg/m(2)/day, five consecutive days with 4-week intervals). In all cohorts, the doses for Cycles 2 to 4 were individualized using pharmacokinetic-pharmacodynamic modeling and simulations. The goal of dose individualization was to determine the maximum dose for each patient at which the occurrence of grade 4 (CTC-AE) toxicities for both platelet and neutrophil counts could be avoided. The initial doses for the following cohorts were also estimated with the data from the previous cohorts in the same manner. RESULTS: In all but one patient (14 out of 15), neutrophil count was the dose-limiting factor throughout the cycles. In cycles where doses were individualized, the median neutrophil nadir observed was 1100/mm(3) (grade 2) and grade 4 toxicity occurred in 5.1 % of all cycles (while it occurred in 36.8 % where doses were not individualized). The initial doses estimated for cohorts 2 to 5 were 4, 5, 5.5, and 5 mg/m(2)/day, respectively. The median maintenance dose was 7 mg/m(2)/day. CONCLUSIONS: We determined the acceptable starting dose and individualized the maintenance dose for each patient, while minimizing the toxicity using the adaptive approach. Currently, 5 mg/m(2)/day is considered to be the most appropriate starting dose for the regimen studied. TRIAL REGISTRATION: Clinicaltrials.gov NCT01277484.

Simulation of PET scan timings for receptor occupancy studies of CNS drugs: a simple fixed-time design performed as well as scattered time point designs.

PURPOSE: This study aimed to determine the effect of PET scan timings on the reliability of occupancy parameter estimates and to identify the scan timing design that gives the most reliable occupancy parameter estimates. METHODS: We compared the performance of designs with various sets of sampling time points using the stochastic simulation and estimation method in Perl-speaks-NONMEM. Biases, relative standard errors, relative estimation errors, and root mean square errors were used to compare the performance of designs. RESULTS: Unlike the results of a previous report, we found that rather complicated designs where each subject or group of subjects are allocated to different scan timings were not superior to the simple, conventional fixed-time designs regardless of whether effect compartment or receptor binding models were used. CONCLUSIONS: We conclude that the conventional fixed-time designs that have been used so far may give robust PD parameter estimates for occupancy data obtained from human PET studies of CNS drugs.