Eriko Kobayashi

Establishment and characterization of two 5-fluorouracil-resistant hepatocellular carcinoma cell lines

5-Fluorouracil (5-FU) chemotherapy is the first choice treatment for advanced hepatocellular carcinoma (HCC), and resistance is the major obstacle to successful treatment. Recent studies have reported that epithelial-to-mesenchymal transition (EMT) is associated with chemoresistance in cancers. We speculated that EMT and 5-FU metabolism are related to the mechanism of 5-FU resistance. First, two 5-FU-resistant cell lines, HLF-R4 and HLF-R10, were established from the HLF undifferentiated human HCC cell line. Whereas cell growth was similar in the HLF and HLF-R cell lines, HLF-Rs are about 4- and 10-fold more resistant compared with the HLF cells; thus, we named these cell lines HLF-R4 and HLF-R10, respectively. The terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling assay also showed a dramatically decreased number of apoptotic cells in the HLF-Rs after treatment with 5-FU. We next assessed the characteristics of the HLF, HLF-R4 and HLF-R10 cells. Consistent with our hypothesis, the HLF-Rs had typical morphologic phenotypes of EMT, loss of cell-cell adhesion, spindle-shaped morphology and increased formation of pseudopodia. Real-time quantitative reverse transcriptase polymerase chain reaction data showed downregulated E-cadherin and upregulated Twist-1 and also indicated that EMT changes occurred in the HLF-Rs. We also found decreased ribonucleotide reductase and increased multidrug resistance protein 5 genes in the HLF-R cells. Our results suggested that the metabolism of EMT and 5-FU has important roles in 5-FU chemoresistance in the HLF-R cells, and that the HLF-R cells would be useful in vitro models for understanding the 5-FU-resistant mechanisms in HCC.

Community pharmacists’ perspectives on generic substitution in Japan

AimThe aim of this study was to evaluate Japanese community pharmacists’ attitudes toward and their recommendation of generic substitution, and to identify the barriers towards performing generic substitution.Subject and methodsA questionnaire survey was conducted from June 2007 to December 2008. A total of 1,590 community pharmacists working for 449 community pharmacies whose owners agreed to participate in the study were involved in the study.ResultsA total of 1,253 community pharmacists responded to the survey (response rate: 78.8%). The majority of respondents (72.1%) were in favor of dispensing generic medicine, but they agreed that they would carefully decide if it is appropriate. In spite of these favorable attitudes, more than half of the respondents (55.6%) seldom or never recommend generic substitution to patients. Respondents indicated four barriers preventing them from performing generic substitution: (1) the generic drug is not in stock or no generic drug equivalent is available yet in the market, (2) only a very small cost savings resulting in patients’ objections, (3) physicians’ objections and (4) presence of skepticism in the quality of generic medicines and inadequate drug information from generic manufacturersConclusionIt is not common for Japanese community pharmacists to recommend generic substitution to patients in spite of their positive attitudes towards generic substitution. Prospective policies on generic substitution are needed to overcome the barriers identified in this study, preventing community pharmacists from performing generic substitutions.

Simultaneous Determination of Morphine, Morphine Glucuronides (M3G, M6G) and Oxycodone in Human Plasma by High-performance Liquid Chromatography

Morphine and oxycodone are widely used as analgesic drugs for cancer pain. Frequently, morphine and oxycodone are given alternately to avoid adverse drug reactions. Morphine is metabolized primarily into two glucuronide metabolites, morphine-3-glucuronide and morphine-6-glucuronide to be pharmacologically active. Morphine-3-glucuronide and morphine-6-glucuronide have neuroexcitatory action and analgesic activity, respectively. Oxymorphone, a metabolite of oxycodone, has an analgesic effect, however it is so small that it can be neglected when considering oxycodone. The pharmacological effects of these drugs and also their metabolites have been reported in experimental papers, but in humans, the relationships between these plasma concentrations and the clinical effects remain unclear. Also the necessity for simultaneous determination of both drugs has been suggested because opioid rotation is performed clinically. However, to date there is no study which has simultaneously determined these four drugs, and also achieved a high recovery. In this paper, in order to perform a reliable pharmacokinetic study of cancer pain patients receiving morphine and oxycodone, an easy, rapid, sensitive and selective analytical method was proposed and validated.

Patients’ perspectives on generic substitution among statin users in Japan

AimThe study was undertaken to reveal the differences in statin users’ characteristics, the views on generic drugs between brand-name statin users and generic statin users, and the factors associated with being generic statin users.Subjects and methodsA questionnaire survey was conducted on patients visiting community pharmacies in order to have their prescriptions including statins dispensed. Respondents answered their views on the questionnaire items using a 5-point Likert-type scale, then answers were dichotomized. Odds ratios were calculated to analyze respondent’s views and respondents’ characteristics associated with being generic users.ResultsIn total, 122 patients agreed to participate in the survey; with regard to respondent’s views associated with being generic statin users, those agreeing “I have a concern in switching any currently taken drugs to generic drugs” were less likely to be generic statin users [OR (95% CI): 0.13, (0.05–0.35)]. Respondents agreeing “generic drugs are less expensive than brand-name drugs” were more likely to be generic users [4.55, (1.77–11.67)]. No respondent’s characteristics were associated with being generic statin users. The majority of respondents agreed “I don’t mind taking the generic drugs that my physician prescribe”. With regard to how much cost savings would encourage them to substitute, 1000–1999 Japanese Yen per pharmacy visit was most often indicated by the respondents.ConclusionA certain level of cost saving is necessary for patients to substitute. Physician-initiated substitution reduce patients’ concerns in switching. The introduction of a kind of policy to widen the price difference between brand-name drugs and generic drugs should be considered as one of the policy options.

Quantitative Assessment of Premium Rates for Clinical Usefulness in New Drug Price Calculation in Japan

Background: In Japan, the reimbursement price of a newly approved drug is calculated according to the rule established by the government. As an incentive to innovative Research & Development, a new drug that meets certain criteria obtains premiums on its price. To quantify the clinical value of new drugs in pricing, a point-based system was proposed by an academic study group. This paper gives the background to and overview of the system, and reviews the drugs that gained the premiums after its introduction. Methods: For drugs to which premiums for innovativeness/usefulness were applied between April 2008 and August 2013, detailed information including the grounds for the premiums was identified. Then, subdivided factors for the requirement of the premium were set and points were allocated to them inductively depending on the degree of clinical impact. Finally, consistency between the rate actually applied and that calculated based on the system were reviewed for new drugs that gained the premiums after its introduction. Results: Forty-seven drugs gained the premium for usefulness between April 2008 and August 2013. Based on the grounds for the premium, a point-based system was established. After its introduction, 11 drugs gained premium for innovativeness/usefulness. The applied rates of premium were consistent with the calculated rate by the system in most cases. Conclusions: Predictability of future drug price is expected to be enhanced by the point-based system. As the control of health expenditure becomes strict, the importance of considering drug pricing policy that properly reflects the drug’s clinical value increases.

Expression of Drug-Resistant Factor Genes in Hepatocellular Carcinoma Patients Undergoing Chemotherapy with Platinum Complex by Arterial Infusion

This study investigated gene expression of drug resistance factors in biopsy tissue samples from hepatocellular carcinoma (HCC) patients undergoing chemotherapy by platinum complex. Liver biopsy was performed to collect tissue from the tumor site (T) and the non-tumor site (NT) prior to the start of treatment. For drug-resistant factors, drug excretion transporters cMOAT and MDR-1, intracellular metal binding protein MT2, DNA repair enzyme ERCC-l and inter-nucleic cell transport protein MVP, were investigated. The comparison of the expression between T and NT indicated a significant decrease of MT2 and MDR-1 in T while a significant increase in ERCC-1 was noted in T. Further, expression was compared between the response cases and non-response cases using the ratios of expression in T to those in NT. The response rate was significantly low in the high expression group when the cutoff value of cMOAT and MT2 was set at 1.5 and 1.0, respectively. Furthermore, when the patients were classified into A group (cMOAT ≧ 1.5 or MT2 ≧ 1.0) and B group (cMOAT < 1.5 and MT2 < 1.0), the response rate of A group was significantly lower than B group when we combined the cutoff values of cMOAT and MT2. It is considered possible to estimate the therapeutic effect of platinum complex at a high probability by combining the expression condition of these two genes.