Hsiao-Hui Tsou

ABCB1 gene polymorphisms are associated with the severity of major depressive disorder and its response to escitalopram treatment

Objective ATP-binding cassette, sub-family B (MDR/TAP), member 1 (ABCB1) is a drug transporter protein expressed on the epithelial cells of the intestine and the endothelial cells of the blood–brain barrier. Intestinal ABCB1 actively transports drugs from the cell membrane and prevents them from entering the blood stream whereas the blood–brain barrier ABCB1 prevents drugs from entering the central nervous system. In this study, we tested whether genetic polymorphisms within the ABCB1 gene are associated with the severity of depression and the effectiveness of the antidepressant, escitalopram (S-CIT), in treating major depressive disorder (MDD). Methods Twenty single nucleotide polymorphisms in the ABCB1 gene were selected and genotyped in 100 MDD patients who had undergone S-CIT treatment continuously for 8 weeks. The serum concentrations of S-CIT and its metabolites (S-desmethylcitalopram and S-didesmethylcitalopram) were then measured at weeks 2, 4, and 8. Results The ABCB1 genotypes of rs1922242 (P=0.0028) and rs1202184 (P=0.0021) showed significant association with the severity of depressive symptoms as assessed by the Hamilton Rating Scale for Depression adjusted with Hamilton Rating Scale for Anxiety. The haplotype block, rs1882478-rs2235048-rs2235047-rs1045642-rs6949448 (from intron 27 to intron 26), of ABCB1 was found strongly associated with the remission rate (global P=0.003, d.f.=69) in which haplotype T-T-T-C-C was associated with a slower remission rate on S-CIT treatment (P=0.001). The haplotypes may not be indicators of the severity of depression or anxiety. Conclusion Our findings suggest that single nucleotide polymorphisms in the ABCB1 gene may be indicators of the severity of depression and of the likely S-CIT treatment remission response in MDD.

A pilot randomized controlled trial to improve geriatric frailty

BackgroundFew randomized controlled trials (RCTs) report interventions targeting improvement of frailty status as an outcome.MethodsThis RCT enrolled 117 older adults (65-79 years of age) in Toufen, Taiwan who scored 3-6 on The Chinese Canadian Study of Health and Aging Clinical Frailty Scale Telephone Version and then score ≥1 on the Cardiovascular Health Study Phenotypic Classification of Frailty (CHS_PCF). With a two by two factorial design, subjects were randomly assigned to interventions (Exercise and nutrition, EN, n = 55 or problem solving therapy, PST, n = 57) or controls (non-EN, n = 62 or non-PST, n = 60). Educational booklets were provided to all. EN group subjects received nutrition consultation and a thrice-weekly exercise-training program while PST group subjects received 6 sessions in 3 month. Subjects were followed at 3, 6, and 12 months. Primary outcome was improvement of the CHS_PCF by at least one category (from pre-frail to robust, or from frail to pre-frail or robust) from baseline assessments. One hundred and one completed final assessments. Intention-to-treat analysis with the generalized estimating equation model was applied with adjustment for time and treatment-by-time interactions.ResultsMean age was 71.4 ± 3.7 years, with 59% females. Baseline characteristic were generally comparable between groups. EN group subjects had a higher improvement rate on the primary outcome than non-EN group subjects (45% vs 27%, adjusted p = 0.008) at 3 months, but not 6 or 12 months. They also had more increase of serum 25(OH) vitamin D level (4.9 ± 7.7 vs 1.2 ± 5.4, p = 0.006) and lower percentage of osteopenia (74% vs 89% p = 0.042) at 12 months. PST group subjects had better improvement (2.7 ± 6.1 vs 0.2 ± 6.7, p = 0.035, 6-month) and less deterioration (−3.5 ± 9.7 vs −7.1 ± 8.7, p = 0.036, 12-month) of dominant leg extension power than non-PST subjects. Some secondary outcomes were also improved in control groups (non-EN or non-PST). No adverse effects were reported.ConclusionsThe three-month EN intervention resulted in short-term (3-month) frailty status improvement and long-term effect on bone mineral density and serum vitamin D (12-month) among Taiwanese community-dwelling elders. The effect of PST was less pronounce.Trial registrationClinicalTrials.gov: EC0970301

CYP2B6 polymorphisms influence the plasma concentration and clearance of the methadone S-enantiomer.

Methadone is a racemic compound composed of the R-form and S-form enantiomers. The drug is usually used in maintenance therapy for the heroin-addicted patients. In our previous study, we found that the cytochrome P-450 (CYP) isozyme 2B6 preferentially metabolizes the S-methadone enantiomer. We thus tested whether CYP2B6 gene polymorphisms had any influence on the concentration or clearance of methadone. Ten single nucleotide polymorphisms within this gene region were evaluated in 366 patients undergoing methadone maintenance for at least 3 months. The plasma steady-state levels of racemic methadone and its metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine were then measured in these individuals. The rs10403955 (T allele in intron 1), rs3745274 (G allele in exon 4), rs2279345 (T allele in intron 5), and rs707265 (A allele in exon 9) CYP2B6 allele types were found to be significantly associated with a higher clearance, a lower plasma concentration, and a lower concentration-to-dosage (C/D) ratio of (S)-methadone (P < 0.0017). Two haplotype blocks of a trinucleotide haplotype (rs8100458-rs10500282-rs10403955 in intron 1) and a hexanucleotide haplotype (rs2279342-rs3745274-rs2279343-rs2279345-rs1038376-rs707265 from intron 2 to exon 9) were constructed within CYP2B6. The major combinations of T-T-T and A-G-A-T-A-A of these particular haplotypes showed significant associations with the plasma concentrations of S-methadone and its C/D ratio (P < 0.0001, respectively). We conclude that genetic polymorphisms in the CYP2B6 gene may therefore be indicators of the clearance, plasma concentration and C/D ratio of S-methadone.

Sample Size Determination for a Specific Region in a Multiregional Trial

Recently, geotherapeutics have attracted much attention from sponsors as well as regulatory authorities. A bridging study defined by the International Conference on Harmonisation (ICH) E5 is usually conducted in the new region after the test product has been approved for commercial marketing in the original region due to its proven efficacy and safety. However, extensive duplication of clinical evaluation in the new region not only requires valuable development resources but also delays availability of the test product to the needed patients in the new regions. To shorten the drug lag or the time lag for approval, simultaneous drug development, submission, and approval in the world may be desirable. On September 28, 2007, the Ministry of Health, Labour and Welfare (MHLW) in Japan published the “Basic Principles on Global Clinical Trials” guidance related to the planning and implementation of global clinical studies. The 11th question and answer for the ICH E5 guideline also discuss the concept of a multiregional trial. Both guidelines have established a framework on how to demonstrate the efficacy of a drug in all participating regions while also evaluating the possibility of applying the overall trial results to each region by conducting a multiregional trial. In this paper, we focus on a specific region and establish statistical criteria for consistency between the region of interest and overall results. More specifically, four criteria are considered. Two criteria are to assess whether the treatment effect in the region of interest is as large as that of the other regions or of the regions overall, while the other two criteria are to assess the consistency of the treatment effect of the specific region with other regions or the regions overall. Sample size required for the region of interest can also be evaluated based on these four criteria.

Genetic polymorphisms in CYP3A4 are associated with withdrawal symptoms and adverse reactions in methadone maintenance patients

AIM Methadone maintenance therapy is one of the standard treatments for heroin addiction. The isozyme CYP3A4 of the CYP system is one of the metabolic enzymes, as well as CYP2B6, responsible for the metabolism of methadone. The aim of the present study is to evaluate the potential use of genetic polymorphisms in CYP3A4 as biomarkers for the prediction of methadone treatment responses. MATERIALS & METHODS A total of 366 Han Chinese methadone maintenance treatment patients in Taiwan were recruited in this study. Main clinical assessments included the clinical opioid withdrawal scale (COWS), the treatment emergent symptom scale (TESS) and the plasma concentrations of methadone and its metabolites. Genetic associations of six SNPs in the CYP3A4 gene were calculated using a general linear model. RESULTS Genotypes and allele types of rs4646440 and rs2242480 were found to be significantly associated with the severity of withdrawal symptoms rated by COWS (p = 0.012, 0.0096, 0.017 and 0.012, respectively) as well as the side effects rated by TESS (p = 0.0089, 0.028, 0.0027 and 0.0085, respectively). The allele types associated with more severe withdrawal symptoms are also associated with more severe side effects and less betel nut (Areca catechu) use (p = 0.009 for rs4646440, p = 0.0063 for rs2242480). Further analyses on specific withdrawal symptoms in COWS showed that the genetic variants in rs4646440 are significantly associated with heart rate (allele type p = 0.0019). CONCLUSION These results suggested that genetic variants in the CYP3A4 gene may be useful indicators for the severity of side effects and withdrawal symptoms for methadone treatment.

Genetic polymorphisms in the opioid receptor mu1 gene are associated with changes in libido and insomnia in methadone maintenance patients

Methadone, a synthetic racemic opioid that primarily works as a μ-opioid receptor (OPRM1) agonist, is commonly used for the treatment of heroin addiction. Genetic association studies have reported that the OPRM1 gene is involved in the physiology of heroin and alcohol addiction. Our current study is designed to test the hypothesis that genetic polymorphisms in the OPRM1 gene region are associated with methadone dosage, plasma concentrations, treatment responses, adverse reactions and withdrawal symptoms in a methadone maintenance treatment (MMT) cohort from Taiwan. Fifteen OPRM1 single nucleotide polymorphisms (SNPs) were selected and genotyped using DNA samples from 366 MMT patients. The plasma concentrations of methadone and its metabolite were measured by high performance liquid chromatography. The results obtained using dominant model analysis indicate that the OPRM1 SNPs rs1074287, rs6912029, rs12209447, rs510769, rs3798676, rs7748401, rs495491, rs10457090, rs589046, rs3778152, rs563649, and rs2075572 are significantly associated with change-in-libido side effects (adjusted p<0.042). Using recessive model analysis, these SNPs were also found to be significantly associated with insomnia side effects in this cohort (p<0.009). The significance of the insomnia findings was mainly contributed by a subgroup of patients who had a positive urine morphine test (p<0.022), and by individuals who did not use benzodiazepine hypnotics (p<0.034). Our current data thus suggest that genetic polymorphisms in OPRM1 may influence the change-in-libido and insomnia side effects sometimes found in MMT patients.

CYP1A2 genetic polymorphisms are associated with treatment response to the antidepressant paroxetine.

AIM Paroxetine is a drug of choice in the treatment of major depressive disorder (MDD). Its metabolism has recently been reported to be mediated through the CYP enzymes 1A2 and 2D6. In our current study, we tested whether genetic polymorphisms in CYP1A2 are associated with the treatment efficacy and side effects of paroxetine. MATERIALS & METHODS A total of 241 MDD patients who had taken paroxetine continually for 8 weeks were recruited, and their steady state paroxetine concentrations were measured at weeks 2, 4 and 8. The genotypes of these patients were then assessed for the presence of nine SNPs, which were selected from either the HapMap Chinese ethnic group, the literature report or through their functional role in the CYP1A2 gene. RESULTS The allele types for SNPs rs4646425 (permutation p = 0.03), rs2472304 (permutation p = 0.01) and rs2470890 (permutation p = 0.004) demonstrated significant associations with paroxetine treatment remission at week 8. Response rates in the Hamilton Rating Scale for Depression (HAM-D) and for The Hamilton Rating Scale for Anxiety (HAM-A) were significantly associated with the SNPs rs4646425 (p = 0.0126 and 0.0088 for HAM-D and HAM-A, respectively) and rs4646427 (p = 0.0067 and 0.0196 for HAM-D and HAM-A, respectively). The inducible SNP rs762551 had a significant association with paroxetine dose at week 4 (permutation p = 0.012). We did not find an association between these SNPs and the side effects or serum concentrations of paroxetine. CONCLUSION Genetic variants in the CYP1A2 region may be indicators of treatment response in MDD patients to paroxetine.

Use of prior information for Bayesian evaluation of bridging studies.

The ICH E5 guideline defines a bridging study as a supplementary study conducted in the new region to provide pharmacodynamic or clinical data on efficacy, safety, dosage, and dose regimen to allow extrapolation of the foreign clinical data to the population of the new region. Therefore, a bridging study is usually conducted in the new region only after the test product has been approved for commercial marketing in the original region based on its proven efficacy and safety. In this paper we address the issue of analysis of clinical data generated by the bridging study conducted in the new region to evaluate the similarity for extrapolation of the foreign clinical data to the population of the new region. Information on efficacy, safety, dosage, and dose regimen of the original region cannot be concurrently obtained from the local bridging studies but available in the trials conducted in the original region. Liu et al. (2002) have proposed a Bayesian approach to synthesize the data generated by the bridging study and foreign clinical data generated in the original region for assessment of similarity based on superior efficacy of the test product over a placebo control. However, the results of the bridging studies using their approach will be overwhelmingly dominated by the results of the original region due to an imbalance of sample sizes between the regions. Therefore, in this paper we propose a Bayesian approach with the use of a mixture prior for assessment of similarity between the new and original region based on the concept of positive treatment effect. Methods for sample size determination for the bridging study are also proposed. Numerical examples illustrate applications of the proposed procedures in different scenarios.

Validation of the Chinese-Canadian study of health and aging clinical frailty scale (CSHA-CFS) telephone version

This was a cross-sectional validation study of the Chinese-Canadian study of health and aging clinical frailty scale telephone version (CSHA-CFS TV). The study pool consisted of 67 patients of outpatient clinics at a tertiary medical center in Taipei, Taiwan. They were enrolled in the program comprehensive geriatric assessment and the frailty study of elderly patients (CGAFSEP). The Chinese-Canadian study of health and aging clinical frailty scale physician version (CSHA-CFS PV) is a 7-point scale assigned after comprehensive geriatric assessments. Higher score indicates frailer status. The Chinese-Canadian study of health and aging clinical frailty scale (CSHA-CFS) telephone version (TV) included 17 questions adapted from the physician version. Two trained research assistants conducted the telephone interviews. Administration time was <3 min. Standard reliability and validity measures were applied. Three-fifths of the subjects were older than 75 years, and half of them were females. Inter-rater reliability was achieved with weighted kappa of 0.684, (p=0.002) between first 20 ratings from 2 interviewers. Criterion validity was achieved with weighted kappa of 0.689 (p<0.0001) and Kendals tau of 0.612 (p<0.0001) between the TV and the PV scores. Divergent validity was demonstrated with significant correlation but only fair agreements comparing both TV and PV scores with the cardiovascular health survey (CHS) phenotypic definition of frailty. One could conclude that the CSHA-CFS TV appears to be a quick, reliable, and valid frailty screening instrument for community-dwelling elderly.

OPRM1 genetic polymorphisms are associated with the plasma nicotine metabolite cotinine concentration in methadone maintenance patients: a cross sectional study

Majority of the heroin-dependent patients smoke cigarettes. Although it has been reported that the OPRM1 genetic polymorphism is associated with the brain mu-opioid receptor binding potential in cigarette smokers, there is no direct evidence showing the impact of plasma cotinine, a nicotine metabolite, on treatment responses to methadone maintenance treatment (MMT). In this study, we aimed to test the hypothesis that the genetic polymorphisms in the OPRM1 are associated with the methadone treatment responses and the severity of cigarette smoking directly measured by the plasma concentration of cotinine in a Taiwanese MMT cohort. Fifteen OPRM1 single-nucleotide polymorphisms (SNPs) were selected and genotyped on DNA samples of 366 MMT patients. Plasma concentrations of cotinine were measured by cotinine enzyme-linked immunosorbent assay. The plasma cotinine concentration had positive correlation with concentrations of methadone (P=0.042) and its metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenyl-pyrrolidine (P=0.037). Methadone treatment non-responders, defined by a positive urine morphine test, had a higher plasma concentration of cotinine (P=0.005), but a lower plasma concentration-to-dose ratio of both R- and S-methadone (P=0.001 and 0.012, respectively) than the responders. OPRM1 genetic variants, rs1074287, rs6912029, rs1799971, rs12209447, rs510769, rs3798676, rs553202, rs7748401, rs495491, rs10457090, rs589046, rs3778152 and rs563649, were significantly associated with the plasma concentration of cotinine when using recessive model for genotypes (general linear model (GLM), P<0.038; false discovery rate (FDR)<0.035) and additive model for allele types (GLM, P<0.03; FDR<0.049) in association analyses. The G allele carriers of SNP rs1799971 (A118G) on exon 1 of OPRM1 gene had a lower plasma cotinine concentration than the A allele carriers (GLM, P=0.029). OPRM1 genetic polymorphisms are associated with the plasma concentration of cotinine in a Taiwanese MMT cohort. Carriers with the major allele of SNP rs1799971 had a higher plasma cotinine concentration.