Yugo Chisaki

Population Pharmacokinetics and Therapeutic Efficacy of Febuxostat in Patients with Severe Renal Impairment

The aim of the present study was to determine the influence of severe renal dysfunction (estimated glomerular filtration rate <30 ml/min/1.73 m2, including hemodialysis) on the pharmacokinetics and therapeutic effects of febuxostat using a population pharmacokinetic analysis. This study recruited patients with hyperuricemia who were initially treated with allopurinol, but were switched to febuxostat, and it consists of 2 sub-studies: a pharmacokinetic study (26 patients) and retrospective efficacy evaluation study (51 patients). The demographic and clinical data of patients were collected from electronic medical records. Plasma febuxostat concentrations were obtained at each hospital visit. Population pharmacokinetic modeling was performed with NONMEM version 7.2. A total of 128 plasma febuxostat concentrations from 26 patients were used in the population pharmacokinetic analysis. The data were best described by a 1-compartment model with first order absorption. Covariate analysis revealed that renal function did not influence the pharmacokinetics of febuxostat, whereas actual body weight significantly influenced apparent clearance and apparent volume of distribution. The retrospective efficacy analysis showed the favorable therapeutic response of febuxostat switched from allopurinol in patients with moderate to severe renal impairment. No serious adverse event associated with febuxostat was observed irrespective of renal function. The population pharmacokinetic analysis and therapeutic analysis of febuxostat revealed that severe renal dysfunction had no influence on the pharmacokinetic parameters of febuxostat. These results suggest that febuxostat is tolerated well by patients with severe renal impairment.

Daphnetin inhibits invasion and migration of LM8 murine osteosarcoma cells by decreasing RhoA and Cdc42 expression.

Daphnetin, 7,8-dihydroxycoumarin, present in main constituents of Daphne odora var. marginatai, has multiple pharmacological activities including anti-proliferative effects in cancer cells. In this study, using a Transwell system, we showed that daphnetin inhibited invasion and migration of highly metastatic murine osteosarcoma LM8 cells in a dose-dependent manner. Following treatment by daphnetin, cells that penetrated the Transwell membrane were rounder than non-treated cells. Immunofluorescence analysis revealed that daphnetin decreased the numbers of intracellular stress fibers and filopodia. Moreover, daphnetin treatment dramatically decreased the expression levels of RhoA and Cdc42. In summary, the dihydroxycoumarin derivative daphnetin inhibits the invasion and migration of LM8 cells, and therefore represents a promising agent for use against metastatic cancer.

Evaluation of thromboembolic events in cancer patients receiving bevacizumab according to the Japanese Adverse Drug Event Report database.

Purpose We aimed to examine the risk factors, time of onset, incidence rates, and outcomes of thromboembolic events induced by bevacizumab in patients with cancer using the Japanese Adverse Drug Event Report (JADER) database of the Pharmaceuticals and Medical Devices Agency. Methods Adverse event data recorded in the JADER database between January 2004 and January 2015 were used. After screening the data using the generic drug name bevacizumab, patient data were classified into two groups by age and five groups by cancer type. The histories of disorders were also categorized. Arterial thromboembolic event and venous thromboembolic event were classified as “favorable” or “unfavorable” outcomes. Results In total, 6076 patients were reported to have developed adverse events during the sample period, of which 233 and 453 developed arterial thromboembolic event and venous thromboembolic event, respectively. Logistic analysis suggested that the presence of cancer was a significant risk factor for both arterial thromboembolic event and venous thromboembolic event. Age (≥70 years), histories of either hypertension or diabetes mellitus were also risk factors for arterial thromboembolic event. Median cumulative times of onset for arterial thromboembolic event and venous thromboembolic event were 60 and 80 days, respectively, and were not significantly different by the log-rank test. By the chi-square test, the rate of unfavorable outcomes was found to be higher after developing arterial thromboembolic event than after venous thromboembolic event. Conclusion Thromboembolism is a leading cause of mortality in patients with cancer. Patients should be monitored for the symptoms of thromboembolic events right from the initial stages of bevacizumab treatment.

Opioid analgesics increase incidence of somnolence and dizziness as adverse effects of pregabalin: a retrospective study

BackgroundPregabalin, a gabapentinoid, is an adjuvant analgesic for treatment of neuropathic pain, but it has serious adverse effects such as somnolence and dizziness, particularly in elderly patients. Although decreased renal function is considered to the contributing factor for high frequency of these adverse effects in elder patients, only a few systematic clinical investigations, especially for hospitalized patients, have been performed on factors that might affect the incidence of its adverse effects. In this study, we performed a retrospective study on the effect of concomitant drugs on induction of somnolence and dizziness as adverse effects of pregabalin in hospitalized patients.MethodsThe subjects were all pregabalin-administered patients in Shiga University of Medical Science Hospital from September 2010 to September 2012, and the subject number was 195. Multivariate logistic regression analysis was performed to determine predictors of the adverse effects, creatinine clearance, duration of pregabalin therapy, initial and maintenance doses of pregabalin, and concomitant drugs, including hypoglycemic drugs, anti-hypertensive ones, non-steroidal anti-inflammatory ones, opioids and central nervous system depressants, being used as independent variables.ResultsThe median initial doses of pregabalin in each renal function group were the same with the case of the defined dose. Although renal function is a well-known factor for prediction of development of adverse effects of pregabalin, we did not detect significant contribution of it. Alternatively, it was demonstrated that concomitant administration of opioids was the significant factor of the incidence of somnolence and dizziness. The first onset date of the adverse effects was frequently detected in the early days of the pregabalin therapy.ConclusionsThe fine tuning of pregabalin dosage schedule based on the renal function appeared to be critical for prevention of development of its adverse effects. Adverse effects tended to develop in the initial phase of pregabalin therapy. Concomitant administration of opioids with pregabalin has the potential to increase the incidence of adverse effects, and thus much more careful attention has to be paid especially in those situations.

Analysis of Adverse Drug Reaction Risk in Elderly Patients Using the Japanese Adverse Drug Event Report (JADER) Database

In general, the risk of adverse drug reactions (ADRs) is higher in elderly patients than in younger patients. In this study, we performed a comprehensive assessment of the risks of possible drug-ADR combinations in elderly patients using the Japanese Adverse Drug Event Report (JADER) database of the Pharmaceutical and Medical Devices Agency (PMDA, Japan) using the reporting odds ratio (ROR) as an index. Data recorded from April 2004 to September 2015 in the JADER database were downloaded from the PMDA website. The patients were classified into younger (≤69 years old) and elderly (≥70 years old) groups. The ROR and 95% confidence interval (CI) were calculated for all combinations of drugs and ADRs for which there were three or more reports in the database, focusing particularly on the combinations where more than 100 cases had been reported in elderly and younger patients. The most frequently reported drug-ADR combination was methotrexate with interstitial lung disease (646 cases). The combination with the highest ROR was methotrexate with lymphoproliferative disorder (ROR: 484.6, 95% CI: 334.1-702.9). In total, 27 drug-ADR combinations were found to have high risk in elderly patients. In conclusion, the findings of this comprehensive assessment of drug-ADR combinations using the JADER database will be valuable for updating the ADR risks for elderly patients in clinical setting.

Population Pharmacodynamic Model for Bayesian Prediction of Myelosuppression Profiles Based on Routine Clinical Data after Gemcitabine and Carboplatin Treatment

Background: Hematological toxicity is a serious adverse event and is often a dose-limiting factor in anticancer drugs. The objective of the present study was to develop a modeling and simulation (M&S) procedure for predictions of time course profiles of blood cell counts that reflect myelosuppression profiles. Methods: A method for Bayesian prediction of myelosuppression profiles during chemotherapy using a population pharmacodynamic model is proposed, and predictabilities of nadir values and times to nadir (Tnadir) after gemcitabine and carboplatin treatment were evaluated. The model is based on an equation for Erlang distribution, which we previously proposed, and it explains time course profiles of platelet (PLT), red blood cell (RBC) and white blood cell (WBC). Results and Conclusion: PLT, RBC and WBC counts were retrospectively collected from 61 time courses (a total of 472 points) of 27 cancer patients. Predictive performance by a one-point Bayesian prediction was evaluated using data from day 8 in consideration of applicability to outpatients. Some good predictability was obtained for nadir values with some exceptions for PLT and RBC, whereas the predictability of Tnadir was insufficient. Although the predictability was not acceptable enough, this M&S approach could be used for supportive care during cancer chemotherapy.

Indication of Adequate Transdermal Fentanyl Dose in Opioid Switching From Oral Oxycodone in Patients With Cancer

Objective: The present study aimed to examine affecting factors for conversion ratio and to predict adequate fentanyl dose for patients with cancer pain in opioid switching from oral oxycodone. Methods: Patient characteristics, biochemical parameters, daily oxycodone dose, and reasons for opioid switching were retrospectively collected. The effect of variables on the conversion ratio was analyzed by multiple regression analysis. Results: Regression analysis for the data from 122 patients suggested that the typical conversion ratio was 95:1; however, this ratio was significantly reduced in patients taking a daily oral morphine-equivalent dose of <45 mg/d and in patients with poor pain control to 52:1 and 64:1, respectively. Conclusion: We should carefully and rapidly control pain in opioid switching based on the adequate dose indicated in this study.