CYP3A-fenotype hos leddgiktpasienter i relasjon til inflammasjonsstatus og behandling med biologiske DMARDs

Bakgrunn: Enzymer tilhørende cytokrom P-450 3A (CYP3A)-subfamilien er de viktigste i metabolisme av legemidler. Systemisk inflammasjon er foreslått som en faktor til den store interindividuelle variabiliteten i CYP3A-fenotype, og 4β-hydroksykolesterol (4β-OH-K) er en aktuell biomarkør for denne variasjonen. Hensikten med dette masterprosjektet var å undersøke om CYP3A-fenotype, målt som serumkonsentrasjon av 4β-OH-K, i) endres etter oppstart med biologiske DMARDs (disease-modifying antirheumatic drugs/ sykdomsmodifiserende antirevmatiske legemidler, bDMARDs) hos leddgiktpasienter, og ii) skiller seg mellom leddgiktpasienter og personer uten kjent revmatisk sykdom. Sekundært skulle det også undersøkes i hvilken grad 4β-OH-K korrelerer med inflammasjonsstatus, målt som CRP og senkningsreaksjon (SR), før og etter oppstart med bDMARDs. Metode: Masterprosjektet tok utgangspunkt i registerstudien NOR-DMARD koordinert av Revmatologisk avdeling, Diakonhjemmet Sykehus. I alt 59 pasienter behandlet med bDMARDs i ca. 3 måneder mot revmatoid artritt (RA) og 52 levetiracetam-behandlede pasienter uten kjent revmatisk sykdom ble inkludert i prosjektet. Serumkonsentrasjon av 4β- OH-K ble bestemt ved bruk av en validert UPLC-APCI-MS/MS-metode ved Senter for Psykofarmakologi, Diakonhjemmet Sykehus. Nivåer av 4β-OH-K og inflammasjonsmarkører (CRP og SR), før og etter oppstart med bDMARDs, ble sammenlignet ved parrede, ikke- parametriske, tester («Wilcoxon»). En ikke-parametrisk, uparret test («Mann-Whitney») ble brukt for sammenligning av 4β-OH-K-konsentrasjoner mellom antatt friske og RA-pasienter, og Spearmans signed rank test ble benyttet i korrelasjonsanalysene mellom 4β-OH-K, CRP og SR. Resultater: Median CRP og SR var redusert, henholdsvis fra 6 til 2 mg/L (p=0.07) og fra 23 til 14 mm/h (p0.3), men etter 3 måneders bDMARD-behandling ble det observert signifikant korrelasjon (p<0.01, Spearman r -0.40 (CRP) og -0.34 (SR)). VI Konklusjon: Denne studien indikerer at CYP3A-fenotype er redusert med ca. 20-30 % i RA- pasienter sammenlignet med pasienter uten inflammatorisk sykdom. Behandling med bDMARDs forbedrer ikke CYP3A-fenotype i løpet av 3 måneder, men CYP3A-fenotype er negativt korrelert med nivå av inflammasjonsmarkører etter oppstart med bDMARDs

Metabolite Profiling of Clozapine in Patients Switching Versus Maintaining Treatment: A Retrospective Pilot Study

Purpose/Background Pharmacokinetics may be of relevance for the risk of clozapine discontinuation. We compared metabolite profiles, accounting for smoking habits, in patients switching versus maintaining clozapine treatment at therapeutic concentrations. Methods/Procedures Adult patients with clozapine serum levels above 1070 nmol/L (350 ng/mL) were retrospectively included from a Norwegian therapeutic drug monitoring service during 2018–2020. Inclusion criteria were (1) known smoking habits, (2) blood sample drawn within 10 to 30 hours after last clozapine intake, and (3) detectable levels of N-desmethylclozapine, clozapine-N-oxide, clozapine-5N-glucuronide, or clozapine-N+-glucuronide. Patients comedicated with cytochrome P450 enzyme inducers, inhibitors, or valproic acid were excluded. The high-resolution mass spectrometry assay enabled detection of 21 clozapine metabolites. Metabolite profiles were compared between patients switching treatment (switchers), measured as clozapine being replaced by another antipsychotic drug in blood samples, versus maintaining clozapine treatment (nonswitchers) during the study period. Findings/Results Of the 84 patients fulfilling the study criteria, 7 patients (8.3%) were identified as clozapine switchers. After correcting for smoking habits, the clozapine-5N-glucuronide/clozapine ratio was 69% lower (P < 0.001), while the clozapine-N+-glucuronide/clozapine-5N-glucuronide ratio was 143% higher (P = 0.026), respectively, in switchers versus nonswitchers. The other metabolite ratios did not significantly differ between switchers and nonswitchers. Implications/Conclusions The present study found a significantly reduced 5N-glucuronidation phenotype in patients switching from clozapine at therapeutic serum concentrations (>1070 nmol/L) to other antipsychotic drugs. This may indicate that glucuronidation, as a potential detoxification mechanism, is related to clozapine tolerability. However, the causality of this observation needs to be investigated in future studies with larger patient populations

Short- and long-term effects of body weight loss following calorie restriction and gastric bypass on CYP3A-activity – a non-randomized three-armed controlled trial

It remains uncertain whether pharmacokinetic changes following Roux-en-Y gastric bypass (RYGB) can be attributed to surgery-induced gastrointestinal alterations per se and/or the subsequent weight loss. The aim was to compare short- and long-term effects of RYGB and calorie restriction on CYP3A-activity, and cross-sectionally compare CYP3A-activity with normal weight to overweight controls using midazolam as probe drug. This three-armed controlled trial included patients with severe obesity preparing for RYGB (n = 41) or diet-induced (n = 41) weight-loss, and controls (n = 18). Both weight-loss groups underwent a 3-week low-energy-diet (<1200 kcal/day) followed by a 6-week very-low-energy-diet or RYGB (both <800 kcal/day). Patients were followed for 2 years, with four pharmacokinetic investigations using semisimultaneous oral and intravenous dosing to determine changes in midazolam absolute bioavailability and clearance, within and between groups. The RYGB and diet groups showed similar weight-loss at week 9 (13 ± 2.4% vs. 11 ± 3.6%), but differed substantially after 2 years (−30 ± 7.0% vs. −3.1 ± 6.3%). At baseline, mean absolute bioavailability and clearance of midazolam were similar in the RYGB and diet groups, but higher compared with controls. On average, absolute bioavailability was unaltered at week 9, but decreased by 40 ± 7.5% in the RYGB group and 32 ± 6.1% in the diet group at year 2 compared with baseline, with no between-group difference. No difference in clearance was observed over time, nor between groups. In conclusion, neither RYGB per se nor weight loss impacted absolute bioavailability or clearance of midazolam short term. Long term, absolute bioavailability was similarly decreased in both groups despite different weight loss, suggesting that the recovered CYP3A-activity is not only dependent on weight-loss through RYGB

Short- and long-term effects of body weight loss following calorie restriction and gastric bypass on CYP3A-activity : a non-randomized three-armed controlled trial

It remains uncertain whether pharmacokinetic changes following Roux-en-Y gastric bypass (RYGB) can be attributed to surgery-induced gastrointestinal alterations per se and/or the subsequent weight loss. The aim was to compare short- and long-term effects of RYGB and calorie restriction on CYP3A-activity, and cross-sectionally compare CYP3A-activity with normal weight to overweight controls using midazolam as probe drug. This three-armed controlled trial included patients with severe obesity preparing for RYGB (n = 41) or diet-induced (n = 41) weight-loss, and controls (n = 18). Both weight-loss groups underwent a 3-week low-energy-diet (&lt;1200 kcal/day) followed by a 6-week very-low-energy-diet or RYGB (both &lt;800 kcal/day). Patients were followed for 2 years, with four pharmacokinetic investigations using semisimultaneous oral and intravenous dosing to determine changes in midazolam absolute bioavailability and clearance, within and between groups. The RYGB and diet groups showed similar weight-loss at week 9 (13 ± 2.4% vs. 11 ± 3.6%), but differed substantially after 2 years (−30 ± 7.0% vs. −3.1 ± 6.3%). At baseline, mean absolute bioavailability and clearance of midazolam were similar in the RYGB and diet groups, but higher compared with controls. On average, absolute bioavailability was unaltered at week 9, but decreased by 40 ± 7.5% in the RYGB group and 32 ± 6.1% in the diet group at year 2 compared with baseline, with no between-group difference. No difference in clearance was observed over time, nor between groups. In conclusion, neither RYGB per se nor weight loss impacted absolute bioavailability or clearance of midazolam short term. Long term, absolute bioavailability was similarly decreased in both groups despite different weight loss, suggesting that the recovered CYP3A-activity is not only dependent on weight-loss through RYGB

Short- and long-term effects of body weight loss following calorie restriction and gastric bypass on CYP3A-activity – a non-randomized three-armed controlled trial

It remains uncertain whether pharmacokinetic changes following Roux-en-Y gastric bypass (RYGB) can be attributed to surgery-induced gastrointestinal alterations per se and/or the subsequent weight loss. The aim was to compare short- and long-term effects of RYGB and calorie restriction on CYP3A-activity, and cross-sectionally compare CYP3A-activity with normal weight to overweight controls using midazolam as probe drug. This three-armed controlled trial included patients with severe obesity preparing for RYGB (n = 41) or diet-induced (n = 41) weight-loss, and controls (n = 18). Both weight-loss groups underwent a 3-week low-energy-diet (<1200 kcal/day) followed by a 6-week very-low-energy-diet or RYGB (both <800 kcal/day). Patients were followed for 2 years, with four pharmacokinetic investigations using semisimultaneous oral and intravenous dosing to determine changes in midazolam absolute bioavailability and clearance, within and between groups. The RYGB and diet groups showed similar weight-loss at week 9 (13 ± 2.4% vs. 11 ± 3.6%), but differed substantially after 2 years (−30 ± 7.0% vs. −3.1 ± 6.3%). At baseline, mean absolute bioavailability and clearance of midazolam were similar in the RYGB and diet groups, but higher compared with controls. On average, absolute bioavailability was unaltered at week 9, but decreased by 40 ± 7.5% in the RYGB group and 32 ± 6.1% in the diet group at year 2 compared with baseline, with no between-group difference. No difference in clearance was observed over time, nor between groups. In conclusion, neither RYGB per se nor weight loss impacted absolute bioavailability or clearance of midazolam short term. Long term, absolute bioavailability was similarly decreased in both groups despite different weight loss, suggesting that the recovered CYP3A-activity is not only dependent on weight-loss through RYGB

Correlations between 4 beta-hydroxycholesterol and hepatic and intestinal CYP3A4 : protein expression, microsomal ex vivo activity, and in vivo activity in patients with a wide body weight range

Purpose Variability in cytochrome P450 3A4 (CYP3A4) metabolism is mainly caused by non-genetic factors, hence providing a need for accurate phenotype biomarkers. Although 4 beta-hydroxycholesterol (4 beta OHC) is a promising endogenous CYP3A4 biomarker, additional investigations are required to evaluate its ability to predict CYP3A4 activity. This study investigated the correlations between 4 beta OHC concentrations and hepatic and intestinal CYP3A4 protein expression and ex vivo microsomal activity in paired liver and jejunum samples, as well as in vivo CYP3A4 phenotyping (midazolam) in patients with a wide body weight range. Methods The patients (n = 96; 78 with obesity and 18 normal or overweight individuals) were included from the COCKTAIL-study (NCT02386917). Plasma samples for analysis of 4 beta OHC and midazolam concentrations, and liver (n = 56) and jejunal (n = 38) biopsies were obtained. The biopsies for determination of CYP3A4 protein concentration and microsomal activity were obtained during gastric bypass or cholecystectomy. In vivo CYP3A4 phenotyping was performed using semi-simultaneous oral (1.5 mg) and intravenous (1.0 mg) midazolam. Results 4 beta OHC concentrations were positively correlated with hepatic microsomal CYP3A4 activity (rho = 0.53, p &lt; 0.001), and hepatic CYP3A4 concentrations (rho = 0.30, p = 0.027), but not with intestinal CYP3A4 concentrations (rho = 0.18, p = 0.28) or intestinal microsomal CYP3A4 activity (rho = 0.15, p = 0.53). 4 beta OHC concentrations correlated weakly with midazolam absolute bioavailability (rho = - 0.23, p = 0.027) and apparent oral clearance (rho = 0.28, p = 0.008), but not with systemic clearance (rho = - 0.03, p = 0.81). Conclusion These findings suggest that 4 beta OHC concentrations reflect hepatic, but not intestinal, CYP3A4 activity. Further studies should investigate the potential value of 4 beta OHC as an endogenous biomarker for individual dose requirements of intravenously administered CYP3A4 substrate drugs