Use of a Bayesian approach in the design and evaluation of NCE2s.

Taiwan's regulatory agency defines New Chemical Entity 2 (NCE2) as a compound drug that has been approved and marketed for ten years in a top-ten pharmaceutically-advanced country but which is new in Taiwan. To apply for registration of NCE2 in Taiwan, a clinical trial may be conducted in Taiwan to evaluate the efficacy and safety. Since the NCE2 has been approved in at least one of the top-ten pharmaceutically-advanced countries, we can borrow the information from all of the observed data from other countries to synthesize the data from both Taiwan and other countries to assess the NCE2 efficacy. In this paper, we propose a Bayesian approach that uses a mixture of prior information to help evaluate an NCE2's efficacy. Numerical examples illustrate applications of the proposed approach in different scenarios. A method for sample-size determination for such trials is also proposed.

rs2841277 (PLD4) is associated with susceptibility and rs4672495 is associated with disease activity in rheumatoid arthritis.

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases, can lead to long-term joint damage, chronic pain, and loss of motor function in the hands, and may share some common genetic factors with other autoimmune disorders, such as ankylosing spondylitis (AS). Many single-nucleotide polymorphisms (SNPs) were reported by genome-wide association studies (GWASs) of RA, but some of them have not been examined in the Taiwanese population. In this study, for 15 SNPs reported in previous RA and AS GWASs, we investigated their association with RA in a Taiwanese population. Based on 334 RA patients recruited from the Taichung Veterans General Hospital and 16,036 healthy subjects from the Taiwan Biobank (TWB) project, we observed that subjects having minor allele C at rs2841277 (phospholipase D family, member 4 (PLD4)) have lower susceptibility of RA, compare to those having genotype TT (Odds ratio (OR) = 0.6, p = 3.0 × 10-6). Among the RA patients, we observed that subjects having GG at rs4672495 have a lower proportion of severe RA, compare to other subjects (OR = 0.09, p = 5.6 × 10-3). Results of a bioinformatics approach showed that rs2841277 is able to influence expression of LINC00638 and AHNAK2 and rs4672495 is able to influence the expression of B3GNT2. In summary, this study replicated an association of rs2841277 with RA susceptibility and showed an AS-associated SNP, rs4672495, is associated with RA activity in the Taiwanese population.

In vitro and in vivo release of dinalbuphine sebacate extended release formulation: Effect of the oil ratio on drug release.

Nalbuphine is a semi-synthetic opioid indicated for the relief of moderate to severe pain. Dinalbuphine sebacate (DNS) is a prodrug of nalbuphine for which we have developed long-acting lipophilic formulations in a benzyl benzoate/sesame oil mixture for intramuscular (IM) injection. In this study, we found that the in vitro release profile of DNS could be affected by adjusting the weight ratio of benzyl benzoate to sesame oil (the solvent/oil ratio). A longer release period could be attained by increasing the solvent/oil ratio in the formulation. A pharmacokinetic study was conducted in beagle dogs to verify the relationship between the in vitro release and the drug release from the formulations in vivo. The pharmacokinetic study confirmed that the formulation with a higher benzyl benzoate to oil ratio exhibits a longer drug release profile with a lower maximum concentration (Cmax) and a longer time to peak blood concentration level (Tmax) than the formulation with a lower benzyl benzoate to oil ratio.

Pharmacokinetics of dinalbuphine sebacate and nalbuphine in human after intramuscular injection of dinalbuphine sebacate in an extended-release formulation.

Nalbuphine is a semi-synthetic opioid indicated for the relief of moderate to severe pain. Its short half-life requires frequent injections in clinical practice, resulting in a greater incidence of adverse events. A prodrug of nalbuphine has been developed, dinalbuphine sebacate (DNS), dissolved in a simple oil-based injectable formulation, which could deliver and maintain an effective blood level of nalbuphine. An open-label, prospective, two-period study was performed in healthy volunteers to verify the extended blood concentration profile of nalbuphine. Twelve healthy Taiwanese were randomized to receive an intramuscular injection of 20 mg nalbuphine HCl and 150 mg DNS sequentially with a washout period of 5 days. To prevent DNS hydrolysis during sample analysis, the effect of four esterase inhibitors was evaluated in the quantitation of DNS in human whole blood and thenoyltrifluoroacetone was chosen. The bioavailability of nalbuphine from intramuscularly injected DNS relative to that from nalbuphine HCl was 85.4%. The mean absorption time of nalbuphine from DNS was 145.2 h. It took approximately 6 days for the complete release of DNS into the blood stream where DNS was rapidly hydrolysed to nalbuphine; suggesting a single injection of 150 mg DNS in our extended-release formulation could provide long-lasting pain relief.

Pharmacokinetics and protein binding of MPT0B292.

MPT0B292 was identified through screening of compounds able selectively to acetylate α-tubulins in cells and it exhibited potent anti-tumor, anti-angiogenesis and anti-metastatic effects in vitro and in vivo. Because of its poor water solubility, MPT0B292 is difficult to formulate with conventional approaches and hence difficulties are experienced in research practices. MPT0B292 was mixed with albumin in an aqueous solvent to form drug albumin nanoparticles with a size range around 333 nm. Unbound fractions of these nanoparticles were investigated in different or the same albumin concentration solutions. Unlike most drugs, the binding of MPT0B292 in human serum albumin increased with increasing drug concentrations. An analytical method was also developed and validated to determine MPT0B292 in rat plasma. This analytical method was applied successfully to the intravenous pharmacokinetic study of MPT0B292 in rats. A single dose study was regularly done to characterize the pharmacokinetic properties of the drug. Additionally, a novel i.v. infusion study was carried out to verify the extraction ratio of MPT0B292. The pharmacokinetic analysis revealed that MPT0B292 was a high extraction ratio drug with high systemic clearance, a high volume of distribution and a short half-life in rats. Copyright © 2017 John Wiley & Sons, Ltd.

rs657075 (CSF2) Is Associated with the Disease Phenotype (BAS-G) of Ankylosing Spondylitis.

Ankylosing spondylitis (AS) is a systemic autoimmune disease mainly affecting the lumbar spine and sacroiliac joints, and exhibits peripheral inflammatory arthropathy. More than 25 loci have been identified as associated with AS. Because both AS and rheumatoid arthritis (RA) are autoimmune diseases that may share some common genetic factors, we therefore examined if the newly identified RA genetic polymorphisms were associated with AS in a Taiwanese population. In this study, we enrolled 475 AS patients and 11,301 healthy subjects from a Taiwanese biobank as controls. Although none of single-nucleotide polymorphisms (SNPs) were associated with the susceptibility to AS, the AS disease index Bath AS Global (BAS-G) clinical phenotype was observed as significantly correlated to the AA genotype of rs657075 (CSF2). The significance remains after gender/age/disease duration adjustment and after group categorization by human leukocyte antigen-B 27 (HLA-B27) genotype. We further investigated the possible functions of rs657075 through bioinformatics approaches. Results revealed that polymorphism of rs657075 is able to influence the expression of acyl-CoA synthetase long-chain family member 6 (ACSL6). In conclusion, our study indicated that rs657075 (CSF2) is strongly associated with the AS disease index Bath AS Global (BAS-G) clinical phenotype.

A statistical analysis to assess the most critical bioequivalence parameters for generic liposomal products.

OBJECTIVES: The purpose of the study was to identify the most sensitive analyte (i.e., encapsulated, free, and total forms) for assessing the bioequivalence (BE) of liposome drug products using Monte Carlo simulation. METHODS: We proposed a liposome classification system that divided liposome drug products into four classes according to the extent of reticuloendothelial system uptake and in vivo release rate: class I: low reticuloendothelial system uptake-rapid release rate; class II: low reticuloendothelial system uptake-slow release rate; class III: high reticuloendothelial system uptake-rapid release rate; Class IV: high reticuloendothelial system uptake-slow release rate. In conjunction with the proposed classification scheme, a variety of drug classes were simulated to determine which analyte provides the most sensitive measure of BE. All drug classes were investigated in single and multiple dose studies. The sensitivity of analytes for measuring BE was evaluated using the power curve. RESULTS AND CONCLUSIONS: Our simulations indicated the encapsulated form provides the most accurate assessment BE for liposome drug products with low reticuloendothelial system uptake (i.e., class I and II). For liposome drug products with high reticuloendothelial system uptake (i.e., class III and IV), the free form provides the best indication BE. Measurement of total drug form to assess BE was preferred only for liposome drug products with low reticuloendothelial system uptake and slow release rates (i.e., class II liposomal drug product). In general, a single dose form is sufficient for demonstrating the BE of liposome drug products.

Evaluation of etanercept dose reduction in patients with rheumatoid arthritis using pharmacokinetic/pharmacodynamic modeling and simulation.

OBJECTIVES: In this study, we attempt to explore the feasibility of alternative dosing regimens of etanercept in patients with rheumatoid arthritis (RA) using pharmacokinetic/pharmacodynamic (PK/PD) modeling and simulation. METHODS: All data used for estimation of PK/PD model parameters were collected from previously published literatures. American College of Rheumatology (ACR) 20/50/70 response rate and a disease activity score in 28 joints (DAS28) was selected as the principal clinical endpoint for further PK/PD modeling. The cumulative AUC (area under the concentration-time curve) of etanercept for different dosing regimens was calculated based on the final PK model and was then linked to the time course of clinical endpoints. Ten different dosing regimens were simulated in this study. RESULTS: The PK model that best fit the serum concentration-time data for etanercept was a one-compartment model with first order absorption and elimination. Based on the PK/PD analysis, the relationship between the predicted cumulative AUC of etanercept to the ACR 20/50/70 response rate and DAS28 score was well characterized by Emax logistic and inhibitory Emax model, respectively. In our simulations, the following dosing regimens that are equally effective to current recommended dosage of 25 mg twice weekly (b.i.w.): (1) 25 mg once weekly (q.w.); (2) 50 mg every 2 weeks (q2w); (3) 25 mg b.i.w. for 3 months and 25 mg q2w thereafter; and (4) 50 mg q.w. for 3 months and 50 mg q2w thereafter. CONCLUSION: In this study, the clinical data was well described by the models developed, and several alternative dosing regimens were proposed. Further clinical studies in patients are still needed to confirm our findings.

Studies on pharmacokinetic mechanism of phenytoin resistance in refractory epilepsy.

P-glycoprotein (P-gp) is a drug efflux pump in many organs, including the intestine and liver. Two single nucleotide polymorphisms (SNPs) of P-gp gene, 2677G>T and 3435C>T, were reported to influence function and expression of P-gp and have the controversial effects on drug disposition. Phenytoin is one substrate of P-gp. Persistent low phenytoin levels in plasma and P-gp overexpression in brain in several refractory epilepsy patients were reported. P-gp polymorphisms may also affect phenytoin efficacy by altering its bioavailability (F). Because two P-gp SNPs, 2677G>T and 3435C>T, may affect P-gp expression in tissue, we examined phenytoin disposition in patients of different P-gp haplotypes, G/G2677C/C3435 and T/T2677T/T3435. We found that the mean absolute F of phenytoin in T/T2677T/T3435 subjects (91%) is slightly higher than in G/G2677C/C3435 subjects (82%). There was no difference in the maximum concentration (Cmax ) and the area under the serum concentration-time curve of phenytoin administered orally between two genotypic groups. However, the time of maximum concentration was higher in T/T2677T/T3435 subjects (10 h) than in G/G2677C/C3435 subjects (6 h). The study ruled out the possibility that genetic polymorphisms of P-gp may affect phenytoin efficacy through the decreased absorption or the increased elimination. P-gp SNPs could affect phenytoin efficacy in refractory epilepsy patients probably because of central nervous system.

Sesamin: A Naturally Occurring Lignan Inhibits CYP3A4 by Antagonizing the Pregnane X Receptor Activation.

Inconsistent expression and regulation of drug-metabolizing enzymes (DMEs) are common causes of adverse drug effects in some drugs with a narrow therapeutic index (TI). An important cytochrome, cytochrome P450 3A4 (CYP3A4), is predominantly regulated by a nuclear receptor, pregnane X receptor (PXR). Sesamin, a major lignan constituent in sesame seeds and oil, exhibits a variety of biological functions; however, the effect of sesamin on the modulation of CYP3A4 is not well understood. In this study, the effects of sesamin on the PXR-CYP3A4 pathway were characterized, as well as the underlying mechanisms of those effects. Sesamin potently attenuated CYP3A4 induction in a dose-dependent manner by blocking the activation of PXR. The PXR inducer-mediated inhibition of CYP3A4 was further evidenced by the ability of sesamin to attenuate the effects of several PXR ligands in the CYP3A4 reporter assay. Further mechanistic studies showed that sesamin inhibited PXR by interrupting the interacting with coregulators. These results may lead to the development of new therapeutic and dietary approaches to reduce the frequency of inducer-drug interaction. Sesamin was established as a novel inhibitor of PXR and may be useful for modulating DMEs expression and drug efficacies. Modification of CYP3A4 expression and activity by consumption of sesamin may have important implications for drug safety.

Polymorphisms of transforming growth factor-ß signaling pathway and Kawasaki disease in the Taiwanese population.

Kawasaki disease (KD) is a systemic vasculitis associated with cardiovascular symptom. A previous study in the European descent has indicated that genetic variants of the transforming growth factor-ß (TGF-ß) pathway are involved in the KD susceptibility and clinical status. This study was conducted to investigate if polymorphisms in TGF-ß signaling pathway are associated with KD susceptibility, and the coronary artery lesion formation. A total of 950 subjects (381 KD patients and 569 controls) were investigated to identify 12 single-nucleotide polymorphisms in the TGF-ß signaling pathway (rs2796817, rs10482751, rs2027567, rs12029576, rs11466480, rs4776338, rs12901071, rs7162912, rs1438386, rs6494633, rs12910698 and rs4776339) by using TaqMan Allelic Discrimination assay. Our results indicated that rs1438386 in the SMAD3 is significantly associated with the susceptibility of KD. Additionally, both haplotypes of TGFß2 and SMAD3 were also associated with the risk of KD. This study showed that genetic polymorphisms in TGF-ß signaling pathway are associated with KD susceptibility, but not coronary artery lesions formation, or intravenous immunoglobulin treatment response in the Taiwanese population.

Inhibition of CYP3A4 expression by ketoconazole is mediated by the disruption of pregnane X receptor, steroid receptor coactivator-1, and hepatocyte nuclear factor 4alpha interaction.

BACKGROUND: Earlier studies have shown that ketoconazole inhibits CYP3A4 expression through pregnane X receptor (PXR)-mediated transcription and coactivator interaction. The involvement of other nuclear receptors remains to be elucidated. It was recently reported that hepatocyte nuclear receptor 4alpha (HNF4alpha), a master regulator of several nuclear receptors, associates with PXR thus regulates the expression of CYP3A4 under rifampin treatment. We therefore focused on the role of PXR-HNF4alpha interaction in the transcriptional regulation of CYP3A4 under rifampin-mediated ketoconazole inhibition. METHODS AND RESULTS: Several approaches were used to characterize this role and to investigate the relation between the regulatory function of the PXR-HNF4alpha complex and CYP3A4 expression, including a mammalian two-hybrid system, DNA affinity precipitation assay, co-immunoprecipitation, and HNF4alpha silencing by RNA interference. Here, we report that HNF4alpha plays a critical role in CYP3A4 promoter activation, and the interaction between PXR and HNF4alpha, which is closely related to the expression of CYP3A4, might be involved in ketoconazole-mediated inhibition of CYP3A4 gene expression. These observations indicate that the inhibition of the interaction of PXR with HNF4alpha is likely an important mechanism of drug-drug interaction.

Interplay of pregnane X receptor with other nuclear receptors on gene regulation.

Human body needs to protect itself from a diverse array of harmful chemicals. These chemicals are also involved in drug metabolism, enzyme induction, and can cause adverse drug-drug interactions. Being a member of nuclear receptors (NRs), pregnane X receptor (PXR) has recently emerged as transcriptional regulators of cytochrome P450 (CYP) and transporters expression so as to against xenobiotics exposure. This review describes some common nuclear receptors, i.e. farnesoid X receptor (FXR), small heterodimer partner (SHP), hepatocyte nuclear factor-4alpha (HNF-4alpha), liver X receptor (LXR), glucocorticoid receptor (GR), constitutive androstane receptor (CAR) that crosstalk with PXR and involvement of coregulators thus control target genes expression.

Androgen receptor gene polymorphism may affect the risk of urothelial carcinoma.

The study sought to explore if androgen receptor gene (AR) polymorphisms are associated with the risk of urothelial carcinoma (UC) which is male-predominant. AR CAG and GGN repeat lengths were analyzed in 277 UC cases and 280 age and sex-matched controls by direct sequencing of leukocyte DNA. Smoking habits were obtained using a structured questionnaire interview. Relative risks were compared between groups categorized by all possible cutoffs of AR CAG and GGN repeat lengths. Men and women who had 23 and 44 (cumulative) CAG repeats had a significantly greater risk of UC, respectively (OR 2.09, 95% CI: 1.05-4.17, p = 0.036 and OR 4.95, 95% CI: 1.56-15.73, p = 0.007). Amongst males who were medium-dose cigarette smokers, those who had 23 CAG and shorter GGN (<22) repeats, had an elevated risk than those with longer CAG and GGN (OR 4.32 and 4.57, p = 0.034 and 0.042, respectively). However, neither CAG nor GGN affected the UC risk in non-smokers or heavy smokers (> or =25 packs per day-years). AR CAG polymorphism may affect the risk of UC in both genders. In addition, AR polymorphisms may influence carcinogenic effect of medium-dose of cigarette smoking in men.

Pregnane X receptor polymorphism affects CYP3A4 induction via a ligand-dependent interaction with steroid receptor coactivator-1.

BACKGROUND: The human pregnane X receptor is a ligand-dependent transcription factor that plays critical roles in regulating detoxification genes such as CYP3A4 by recruiting transcriptional coactivators such as steroid receptor coactivator-1 in a ligand-dependent manner. In a previous study (Pharmacogenetics and Genomics 2005, 15: 337-341), we reported a novel pregnane X receptor single nucleotide polymorphism, Q158K, which impaired transactivation of CYP3A4. METHODS AND RESULTS: By using DNA affinity precipitation assay and electrophoretic mobility shift assay, we have now shown that Q158K does not alter the binding affinity of pregnane X receptor for the CYP3A4 promoter. Instead, as shown using a mammalian two-hybrid assay, it decreased the interaction of pregnane X receptor with steroid receptor coactivator-1 in the presence of rifampin, clotrimazole, paclitaxel, or nifedipine but not in their absence. Rifampin treatment markedly increased pregnane X receptor protein in the wild-type pregnane X receptor-transfected cells as shown by coimmunoprecipitation but not in Q158K pregnane X receptor-transfected cells. The impaired transactivation of the CYP3A4 promoter was reversed by transfecting steroid receptor coactivator-1 expression plasmids. An additional nine pregnane X receptor variants were isolated and selected by random mutagenesis. Mutations Q158, W223, F257, I346, and L424 also reduced CYP3A4 transactivation and interaction in mammalian two-hybrid assays only in the presence of ligands. Although Q158K did not greatly affect the interaction of pregnane X receptor to silencing mediator of retinoid and thyroid hormone receptor, pregnane X receptor-silencing mediator of retinoid and thyroid hormone receptor interaction was impaired in the F257L and I346T variants with or without the presence of pregnane X receptor ligands. CONCLUSION: Our data indicate that the impaired induction by the Q158K variant is probably due to defective steroid receptor coactivator-1 interaction in the presence of a pregnane X receptor ligand. As the whole ligand binding domain of pregnane X receptor is required for the interaction with steroid receptor coactivator-1, we propose that, not only the Q158K variant found in Chinese, but also in native pregnane X receptor variants in other ethnic groups (D163G, A370T, R381W, and I403V) affect CYP3A4 induction by altering steroid receptor coactivator-1 recruitment.

The effects of ergoloid mesylates and ginkgo biloba on the pharmacokinetics of ticlopidine.

Ticlopidine is sometimes coadministered with ergoloid mesylates or ginkgo biloba in clinical situations. Our objective was to examine the effect of ergoloid mesylates and ginkgo biloba on ticlopidine pharmacokinetics. Ticlopidine, ergoloid mesylates, and ginkgo biloba significantly inhibited the organic anion transporting polypeptide (OATP-B)-mediated uptake of [(3)H]-estrone-3-sulfate in a concentration-dependent manner. When ergoloid mesylates was coadministered with ticlopidine, the ticlopidine area under the plasma drug concentration-time profile (AUC) from 0 to 12 hours was decreased 30% and the peak plasma drug concentration (C(max)) was decreased 29%, compared with ticlopidine administration alone. There were no significant changes in the pharmacokinetic parameters of ticlopidine when it was coadministered with ginkgo biloba. In summary, ergoloid mesylates is a more potent inhibitor of OATP-B than is ginkgo biloba, and it can reduce the oral bioavailability of drugs transported by OATP-B. Ergoloid mesylates markedly decreased the AUC and C(max) of ticlopidine, probably by inhibiting the OATP-B-mediated uptake of ticlopidine during the intestinal absorption phase. The results support a new model of intestinal drug-drug interaction.

Enhanced expression of multidrug resistance-associated protein 2 and reduced expression of aquaglyceroporin 3 in an arsenic-resistant human cell line.

Arsenic-resistant cells (R15), derived from a human lung adenocarcinoma cell line (CL3), were 10-fold more resistant to sodium arsenite (As(III)). Because R15 cells accumulated less arsenic than parental CL3 cells, this arsenic resistance may be due to higher efflux and/or lower uptake of As(III). We therefore compared expression of the multidrug resistance-associated proteins MRP1, MRP2, and MRP3 in these two cell lines. MRP2 expression was 5-fold higher in R15 cells than in CL3 cells, whereas MRP1 and MRP3 expression levels were similar. Furthermore, verapamil and cyclosporin A, inhibitors of multidrug resistance transporters, significantly reduced the efflux of arsenic from R15. Thus, increased arsenic extrusion by MRP2 may contribute to arsenic resistance in R15 cells. We also examined the expression of several aquaglyceroporins (AQPs), which mediate As(III) uptake by cells. Little AQP7 or AQP9 mRNA was detected by reverse transcription-PCR in either cell line, whereas AQP3 mRNA expression was 2-fold lower in R15 cells than in CL3 cells. When AQP3 expression in CL3 cells was knocked down by RNA interference, CL3 cells accumulated less arsenic and became more resistant to As(III). Conversely, overexpression of AQP3 in human embryonic kidney 293T cells increased arsenic accumulation, and the cells were more susceptible to As(III) than 293T cells transfected with vector alone. These results suggest that AQP3 is involved in As(III) accumulation. Taken together, our results suggest that enhanced expression of MRP2 and lower expression of AQP3 are responsible for lower arsenic accumulation in arsenic-resistant R15 cells.

Phase I and pharmacokinetic study of oral thalidomide in patients with advanced hepatocellular carcinoma.

PURPOSE: To evaluate the dose-limiting toxicities (DLT), maximum tolerated dose (MTD), and pharmacokinetics of thalidomide in patients with advanced hepatocellular carcinoma (HCC). METHODS: Patients with advanced HCC who were not feasible for definitive local therapy were eligible. Patients were enrolled in a cohort of three to receive thalidomide twice daily for 1 week to determine the MTD. Intra-patient dose escalation was permitted. Pharmacokinetic studies were performed at the first dose level and repeated at the second dose level of each patient. RESULTS: Fifteen patients were accrued at four dose levels with the starting dose range 100-400 mg/day. Two patients at 400 mg/day experienced DLT (grade 3 angioedema and dyspnea, respectively). The MTD of twice-daily schedule was determined as 300 mg/day. The mean steady-state maximal blood concentration and mean steady-state area under the curve had a trend toward positive correlation, but non-linear proportionate, to the daily dose of thalidomide. Pharmacokinetic parameters are comparable for patients of Child-Pugh's A and B. Apparent mild, transient drug-induced transaminitis was early onset, self-limited, which occurred in 30.7% of patients. Serum hepatitis B or C viral titers was largely not affected. CONCLUSION: The absorption and elimination of thalidomide are not significantly different in HCC patients with compensated or decompensated hepatic dysfunction.