Jocelyne Chabert

The AmpliChip CYP450 test: cytochrome P450 2D6 genotype assessment and phenotype prediction

Polymorphisms of the cytochrome P450 2D6 (CYP2D6) gene affecting enzyme activity are involved in interindividual variability in drug efficiency/toxicity. Four phenotypic groups are found in the general population: ultra rapid (UM), extensive (EM), intermediate (IM) and poor (PM) metabolizers. The AmpliChip CYP450 test is the first genotyping array allowing simultaneous analysis of 33 CYP2D6 alleles. The main aim of this study was to evaluate the performance of this test in CYP2D6 phenotype prediction. We first verified the AmpliChip CYP450 test genotyping accuracy for five CYP2D6 alleles routinely analysed in our laboratory (alleles 3,4,5,6, × N; n=100). Results confirmed those obtained by real-time PCR. Major improvements using the array are the detection of CYP2D6 intermediate alleles and identification of the duplicated alleles. CYP2D6 phenotype was determined by assessing urinary elimination of dextromethorphan and its metabolite dextrorphan and compared to the array prediction (n=165). Although a low sensitivity of UM prediction by genotyping was observed, phenotype prediction was optimal for PM and satisfying for EM and IM.

Influence of ABCB1 Gene Polymorphisms and P-Glycoprotein Activity on Cyclosporine Pharmacokinetics in Peripheral Blood Mononuclear Cells in Healthy Volunteers

The calcineurin inhibitor cyclosporine is removed from lymphocytes by the drug efflux transporter P-glycoprotein (P-gp) encoded by the ABCB1 gene for which several single nucleotide polymorphisms (SNPs) have been identified. Of a total of 87 healthy volunteers genotyped for ABCB1 G2677T/A and C3435T SNPs, 10 GG-CC and 9 TT-TT individuals were selected and received a single oral dose of cyclosporine. Peripheral blood mononuclear cell (PBMC) ABCB1 mRNA expression, P-gp activity in CD4(+) and CD8(+) cells and the 24h cyclosporine pharmacokinetics in PBMCs and whole blood were determined. No correlation was observed between cyclosporine PBMC and whole blood levels (AUC(0-24), Spearman, r(S)=0.09, p=0.71). Intraindividual PBMC and whole blood levels followed parallel profiles that did not significantly differ with respect to t(max) (Wilcoxon, p=0.53) and t((1/2)) (p=0.49). Significant negative correlations between cyclosporine t((1/2)) in PBMCs and P-gp activity in CD4(+) (r(S)=-0.82, p=0.007) and CD8(+) (r(S)=-0.72, p=0.03) were observed among TT-TT subjects. Similarly, a negative correlation was detected in the GG-CC group between P-gp activity in CD4(+) and cyclosporine PBMC AUC(0-24) (r(S)=-0.69, p=0.03), as well as PBMC to whole blood AUC(0-24) ratio (r(S)=-0.60, p=0.07). Tested ABCB1 genotypes had no influence on cyclosporine pharmacokinetic parameters in PBMCs and whole blood. The haplotypes investigated were neither significantly correlated with PBMC ABCB1 mRNA expression nor with P-gp activity in CD4(+) and CD8(+). In conclusion, cyclosporine PBMC pharmacokinetics was influenced by P-gp activity and cyclosporine whole blood concentrations did not predict PBMC drug levels, suggesting that despite values in the therapeutic range, some subjects could have inadequate intracellular drug levels.

Oral Flurbiprofen Metabolic Ratio assessment Using a Single-Point Dried Blood Spot

We investigated whether a single blood measurement using the minimally invasive technique of a finger prick to draw a blood sample of 5 µl (to yield a dried blood spot (DBS)) is suitable for the assessment of flurbiprofen (FLB) metabolic ratio (MR). Ten healthy volunteers who had been genotyped for CYP2C9 were recruited as subjects. They received FLB alone in session 1 and FLB with fluconazole in session 2. In session 3, the subjects were pretreated for 4 days with rifampicin and received FLB with the last dose of rifampicin on day 5. Plasma and DBS samples were obtained between 0 and 8 h after FLB administration, and urine was collected during the 8 h after administration. The pharmacokinetic profiles of the drugs were comparable in DBS and plasma. FLBs apparent clearance values decreased by 35% in plasma and DBS during session 2 and increased by 75% in plasma and by 30% in DBS during session 3. Good correlations were observed between MRs calculated from urine, plasma, and DBS samples.

Using venlafaxine to treat behavioral disorders in patients with autism spectrum disorder.

OBJECTIVE To test the efficacy of venlafaxine at a dose of 18.75 mg/day on the reduction of behavioral problems such as irritability and hyperactivity/noncompliance in patients with intellectual disabilities and autism spectrum disorder (ASD). Our secondary hypothesis was that the usual doses of zuclopenthixol and/or clonazepam would decrease in the venlafaxine-treated group. METHODS In a randomized double-blind study, we compared six patients who received venlafaxine along with their usual treatment (zuclopenthixol and/or clonazepam) with seven patients who received placebo plus usual care. Irritability, hyperactivity/noncompliance, and overall clinical improvement were measured after 2 and 8 weeks, using validated clinical scales. RESULTS Univariate analyses showed that the symptom of irritability improved in the entire sample (p = 0.023 after 2 weeks, p = 0.061 at study endpoint), although no difference was observed between the venlafaxine and placebo groups. No significant decrease in hyperactivity/noncompliance was observed during the study. At the end of the study, global improvement was observed in 33% of participants treated with venlafaxine and in 71% of participants in the placebo group (p = 0.29). The study found that decreased cumulative doses of clonazepam and zuclopenthixol were required for the venlafaxine group. Multivariate analyses (principal component analyses) with at least three combinations of variables showed that the two populations could be clearly separated (p b 0.05). Moreover, in all cases, the venlafaxine population had lower values for the Aberrant Behavior Checklist (ABC), Behavior Problems Inventory (BPI), and levels of urea with respect to the placebo group. In one case, a reduction in the dosage of clonazepam was also suggested. For an additional set of variables (ABC factor 2, BPI frequency of aggressive behaviors, hematic ammonia at Day 28, and zuclopenthixol and clonazepam intake), the separation between the two samples was statistically significant as was the Bartletts test, but the Kaiser–Meyer–Olkin Measure of Sampling Adequacy was below the accepted threshold. This set of variables showed a reduction in the cumulative intake of both zuclopenthixol and clonazepam. CONCLUSION Despite the small sample sizes, this study documented a statistically significant effect of venlafaxine. Moreover, we showed that lower doses of zuclopenthixol and clonazepam were needed in the venlafaxine group, although this difference was not statistically significant. This was confirmed by multivariate analyses, where this difference reached statistical significance when using a combination of variables involving zuclopenthixol. Larger-scale studies are recommended to better investigate the effectiveness of venlafaxine treatment in patients with intellectual disabilities and ASD.

420 SIGNIFICANCE OF GENETIC AND NEUROPHYSIOLOGICAL ASPECTS IN FIBROMYALGIA

Background and Aims: The published experience about the multidisciplinary treatment of fibromyalgia is controversial. Our aim is to describe the results of our multidisciplinary treatment in a group of selected fibromyalgia patients with disability, and willing to return to work. Methods: After multidisciplinary meeting, 264 patients with fibromyalgia (94% female; mean age 43 (8.6) years) were included in the study, and allocated by consensus to an intensive medical, psychological, physical and occupational treatment (twelve sessions, three-day weekly basis). Patients were affected by significant disability, were free of major psychopathology (suicide risk, schizophrenia or other psychotic disorders, and severe personality disorder), considered return-to-work as a therapeutic aim, and were not applying for disability pension or in the course of labor litigation. All patients were followed at discharge, and at 6 and 12 months. Results: Significant differences were observed in pain (VAS) at discharge (Mean difference: 3.1; p< 0.01), at 6 and at 12-month follow-up (Mean difference: 2.1 and 3.2; p< 0.01), in depressive symptoms at discharge and at 12 month follow-up (Mean difference (BDI): 5.7 and 8.4; p< 0.01), and in functional ability (HAQ) at discharge, at 6 and at 12 month follow-up (Mean difference: 0.8, 0.8 and 0.9 respectively p< 0.01). At discharge, 63% of patients returned to work. Conclusions: The intensive multidisciplinary treatment for fibromyalgia is effective in patients with possibilities of functional restoration, and willing to return to work.

419 CENTRAL PAIN SENSITIZATION AND PSYCHOLOGICAL FACTORS IN FIBROMYALGIA

Background and Aims: The published experience about the multidisciplinary treatment of fibromyalgia is controversial. Our aim is to describe the results of our multidisciplinary treatment in a group of selected fibromyalgia patients with disability, and willing to return to work. Methods: After multidisciplinary meeting, 264 patients with fibromyalgia (94% female; mean age 43 (8.6) years) were included in the study, and allocated by consensus to an intensive medical, psychological, physical and occupational treatment (twelve sessions, three-day weekly basis). Patients were affected by significant disability, were free of major psychopathology (suicide risk, schizophrenia or other psychotic disorders, and severe personality disorder), considered return-to-work as a therapeutic aim, and were not applying for disability pension or in the course of labor litigation. All patients were followed at discharge, and at 6 and 12 months. Results: Significant differences were observed in pain (VAS) at discharge (Mean difference: 3.1; p< 0.01), at 6 and at 12-month follow-up (Mean difference: 2.1 and 3.2; p< 0.01), in depressive symptoms at discharge and at 12 month follow-up (Mean difference (BDI): 5.7 and 8.4; p< 0.01), and in functional ability (HAQ) at discharge, at 6 and at 12 month follow-up (Mean difference: 0.8, 0.8 and 0.9 respectively p< 0.01). At discharge, 63% of patients returned to work. Conclusions: The intensive multidisciplinary treatment for fibromyalgia is effective in patients with possibilities of functional restoration, and willing to return to work.

Pharmacokinetics and analgesic effects of intravenous buprenorphine

buprenorphine (BUP), a semi‐synthetic opioid, is used as an analgesic for post‐operative and chronic pain. Because of very low plasma concentrations its pharmacokinetics and related pharmacodynamics are not well characterized. BUP pharmacokinetics and pharmacodynamics were investigated as part of a study on the efficacy of naltrexone (NTX) in reversing its analgesic effects.