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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).

AGM-130 is a cyclin-dependent kinase inhibitor that exhibits dose-dependent efficacy in xenograft mouse models. During preclinical pharmacokinetic (PK) studies, mice and rats showed comparable PK parameters while dogs showed unusually high clearance (CL), which has made human PK prediction challenging. To address this discrepancy, we performed a human microdosing PK and developed a mouse PK/PD model in order to guide the first-in-human studies. A microdose of AGM-130 was given via intravenous injection to healthy subjects. Efficacy data obtained using MCF-7 breast cancer cells implanted in mice was analyzed using pre-existing tumor growth inhibition models. We simulated a human PK/PD profile with the PK parameters obtained from the microdose study and the PD parameters estimated from the xenograft PK/PD model. The human CL of AGM-130 was 3.08 L/h/kg, which was comparable to CL in mice and rats. The time-courses of tumor growth in xenograft model was well described by a preexisting model. Our simulation indicated that the human doses needed for 50 and 90% inhibition of tumor growth were about 100 and 400 mg, respectively. This is the first report of using microdose PK and xenograft PK/PD model to predict efficacious doses before the first-in-human trial in cancer patients. In addition, this work highlights the importance of integration of all of information in PK/PD analysis and illustrates how modeling and simulation can be used to add value in the early stages of drug development.

Gab-jin Park,1 Soo Hyeon Bae,1 Wan-Su Park,1 Seunghoon Han,1 Min-Ho Park,2 Seok-Ho Shin,2 Young G Shin,2 Dong-Seok Yim1,2 1Department of Clinical Pharmacology and Therapeutics, Seoul St Mary’s Hospital, PIPET (Pharmacometrics Institute for Practical Education and Training), College of Medicine, Catholic University of Korea, Seoul, South Korea; 2College of Pharmacy, Chungnam National University, Daejeon, South Korea Purpose: A microdose drug–drug interaction (DDI) study may be a valuable tool for anticipating drug interaction at therapeutic doses. This study aimed to compare the magnitude of DDIs at microdoses and regular doses to explore the applicability of a microdose DDI study. Patients and methods: Six healthy male volunteer subjects were enrolled into each DDI study of omeprazole (victim) and known perpetrators: fluconazole (inhibitor) and rifampin (inducer). For both studies, the microdose (100 µg, cold compound) and the regular dose (20 mg) of omeprazole were given at days 0 and 1, respectively. On days 2–9, the inhibitor or inducer was given daily, and the microdose and regular dose of omeprazole were repeated at days 8 and 9, respectively. Full omeprazole pharmacokinetic samplings were performed at days0, 1, 8, and 9 of both studies for noncompartmental analysis. Results: The magnitude of the DDI, the geometric mean ratios (with perpetrator/omeprazole only) of maximum concentration (Cmax) and area under the curve to the last measurement (AUCt) of the microdose and the regular dose were compared. The geometric mean ratios in the inhibition study were: 2.17 (micro) and 2.68 (regular) for Cmax, and 4.07 (micro), 4.33 (regular) for AUCt. For the induction study, they were 0.26 (micro) and 0.21 (regular) for Cmax, and 0.16 (micro) and 0.15 (regular) for AUCt. There were no significant statistical differences in the magnitudes of DDIs between microdose and regular-dose conditions, regardless of induction or inhibition. Conclusion: Our results may be used as partial evidence that microdose DDI studies may replace regular-dose studies, or at least be used for DDI-screening purposes. Keywords: drug–drug interaction, microdose, CYP2C19

Taegon Hong,1,2 Seunghoon Han,1,2 Jongtae Lee,1,2 Sangil Jeon,1,2 Gab-Jin Park,1,2 Wan-Su Park,1,2 Kyoung Soo Lim,3 Jae-Yong Chung,4 Kyung-Sang Yu,3 Dong-Seok Yim1,2 1Department of Pharmacology, College of Medicine, the Catholic University of Korea, Seoul, Republic of Korea; 2PIPET (Pharmacometrics Institute for Practical Education and Training), the Catholic University of Korea, Seoul, Republic of Korea; 3Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of Korea; 4Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Bundang Hospital, Seongnam, Republic of Korea Abstract: A single 400 mg dose of moxifloxacin has been the standard positive control for thorough QT (TQT) studies. However, it is not clearly known whether a 400 mg dose is also applicable to TQT studies in Asian subjects, including Koreans. Thus, we aimed to develop a pharmacokinetic (PK)-pharmacodynamic (PD) model for moxifloxacin, to evaluate the time course of its effect on QT intervals in Koreans. Data from three TQT studies of 33 healthy male Korean subjects who received 400 and 800 mg of moxifloxacin and placebo (water) were used. Twelve-lead electrocardiograms were taken for 2 consecutive days: 1 day to record diurnal changes and the next day to record moxifloxacin or placebo effects. Peripheral blood samples were also obtained for PK analysis. The PK-PD data obtained were analyzed using a nonlinear mixed-effects method (NONMEM ver. 7.2). A two-compartment linear model with first-order absorption provided the best description of moxifloxacin PK. Individualized QT interval correction, by heart rate, was performed by a power model, and the circadian variation of QT intervals was described by two mixed-effect cosine functions. The effect of moxifloxacin on QT interval prolongation was well explained by the nonlinear dose-response (Emax) model, and the effect by 800 mg was only slightly greater than that of 400 mg. Although Koreans appeared to be more sensitive to moxifloxacin-induced QT prolongation than were Caucasians, the PK-PD model developed suggests that a 400 mg dose of moxifloxacin is also applicable to QT studies in Korean subjects. Keywords: thorough QT study, PK-PD model, NONMEM, Emax model

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.

In this paper we will define semi-Girard quantales whose properties are weaker than the properties of Girard quantales. We will give an example which is a simi-Girard quantale but not a Girard quantale. We will show that the right(or left) divisor of the dualizing element by itself is the identity of a semi-Girard Quantale. We will define some derivations on a simi-Girard quantale whose dualizing element is the bottom element 0, and investigate some properties of such derivations. Mathematics Subject Classification: 06F07, 06F25

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 naive 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 AUC last 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 AUC last 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).

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/m2/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/mm3 (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/m2/day, respectively. The median maintenance dose was 7 mg/m2/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/m2/day is considered to be the most appropriate starting dose for the regimen studied. Trial registration Clinicaltrials.gov NCT01277484

'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.

Gab-jin Park, Wan-Su Park, Soohyun Bae, Sung-min Park, Seunghoon Han and Dong-Seok Yim* Department of Clinical Pharmacology and Therapeutics, Seoul St. Mary’s Hospital, PIPET (Pharmacometrics Institute for Practical Education and Training), College of Medicine, The Catholic University of Korea, Seoul 06591, Korea *Correspondence: D. S. Yim; Tel: +82-2-2258-7327, Fax: +82-2-2258-7876, E-mail: yimds@catholic.ac.kr

Sunil Youn, Wan-su Park, Gab-jin Park, Doo Yeon Jang, Soo Hyeon Bae, Seunghoon Han* and Dong-Seok Yim Department of Clinical Pharmacology and Therapeutics, Seoul St. Mary’s Hospital, PIPET (Pharmacometrics Institute for Practical Education and Training), College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea *Correspondence: S. H. Han; Tel: +82-2-2258-7326, Fax: +82-2-2258-7876, E-mail: waystolove@catholic.ac.kr

Seunghoon Han,1,2 Sangil Jeon,1,2 Taegon Hong,1,2 Jongtae Lee,1,2 Soo Hyeon Bae,1,2 Wan-su Park,1,2 Gab-jin Park,1,2 Sunil Youn,1,2 Doo Yeon Jang,1,2 Kyung-Soo Kim,3 Dong-Seok Yim1,2 1Department of Pharmacology, College of Medicine, The Catholic University of Korea, 2Pharmacometrics Institute for Practical Education and Training, 3Department of Family Medicine, Seoul St Mary’s Hospital, Seochogu, Seoul, Republic of KoreaAbstract: No wholly successful weight-control drugs have been developed to date, despite the tremendous demand. We present an exposure–response model of sibutramine mesylate that can be applied during clinical development of other weight-control drugs. Additionally, we provide a model-based evaluation of sibutramine efficacy. Data from a double-blind, randomized, placebo-controlled, multicenter study were used (N=120). Subjects in the treatment arm were initially given 8.37mg sibutramine base daily, and those who lost