Short- and long-term effects of body weight, calorie restriction and gastric bypass on CYP1A2, CYP2C19 and CYP2C9 activity.

AIM: Roux-en-Y gastric bypass (RYGB) may influence drug disposition due to surgery-induced gastrointestinal alterations and/or subsequent weight loss. The objective was to compare short- and long-term effects of RYGB and diet on the metabolic ratios of paraxanthine/caffeine (cytochrome P450 [CYP] 1A2 activity), 5-hydroxyomeprazole/omeprazole (CYP2C19 activity) and losartan/losartan carboxylic acid (CYP2C9 activity), and cross-sectionally compare these CYP-activities with normal-to-overweight controls. METHODS: This trial included patients with severe obesity preparing for RYGB (n = 40) 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, weeks 0-3) followed by a 6-week very-low-energy diet or RYGB (both <800 kcal/day, weeks 3-9). Follow-up time was 2 years, with four pharmacokinetic investigations. RESULTS: Mean ± SD weight loss from baseline was similar in the RYGB-group (13 ± 2.4%) and the diet group (10.5 ± 3.9%) at week 9, but differed at year 2 (RYGB -30 ± 6.9%, diet -3.1 ± 6.3%). From weeks 0 to 3, mean (95% confidence interval [CI]) CYP2C19 activity similarly increased in both groups (RYGB 43% [16, 55], diet 48% [22, 60]). Mean CYP2C19 activity increased by 30% (2.6, 43) after RYGB (weeks 3-9), but not in the diet-group (between-group difference -0.30 [-0.63, 0.03]). CYP2C19 activity remained elevated in the RYGB group at year 2. Baseline CYP2C19 activity was 2.7-fold higher in controls compared with patients with obesity, whereas no difference was observed in CYP1A2 and CYP2C9 activities. CONCLUSION: Our findings suggest that CYP2C19 activity is lower in patients with obesity and increases following weight loss. This may be clinically relevant for drug dosing. No clinically significant effect on CYP1A2 and CYP2C9 activities was observed.

Correlations between 4ß-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 4ß-hydroxycholesterol (4ßOHC) is a promising endogenous CYP3A4 biomarker, additional investigations are required to evaluate its ability to predict CYP3A4 activity. This study investigated the correlations between 4ßOHC 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 4ßOHC 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: 4ßOHC concentrations were positively correlated with hepatic microsomal CYP3A4 activity (ρ = 0.53, p < 0.001), and hepatic CYP3A4 concentrations (ρ = 0.30, p = 0.027), but not with intestinal CYP3A4 concentrations (ρ = 0.18, p = 0.28) or intestinal microsomal CYP3A4 activity (ρ = 0.15, p = 0.53). 4ßOHC concentrations correlated weakly with midazolam absolute bioavailability (ρ = - 0.23, p = 0.027) and apparent oral clearance (ρ = 0.28, p = 0.008), but not with systemic clearance (ρ = - 0.03, p = 0.81). CONCLUSION: These findings suggest that 4ßOHC concentrations reflect hepatic, but not intestinal, CYP3A4 activity. Further studies should investigate the potential value of 4ßOHC as an endogenous biomarker for individual dose requirements of intravenously administered CYP3A4 substrate drugs. TRIAL REGISTRATION: Clinical. TRIALS: gov identifier: NCT02386917.

Glucagon Like Peptide 1 Receptor Agonists for Targeted Delivery of Antisense Oligonucleotides to Pancreatic Beta Cell.

The extra hepatic delivery of antisense oligonucleotides (ASOs) remains a challenge and hampers the widespread application of this powerful class of therapeutic agents. In that regard, pancreatic beta cells are a particularly attractive but challenging cell type because of their pivotal role in diabetes and the fact that they are refractory to uptake of unconjugated ASOs. To circumvent this, we have expanded our understanding of the structure activity relationship of ASOs conjugated to Glucagon Like Peptide 1 Receptor (GLP1R) agonist peptide ligands. We demonstrate the key role of the linker chemistry and its optimization to design maleimide based conjugates with improved in vivo efficacy. In addition, truncation studies and scoping of a diverse set of GLP1R agonists proved fruitful to identify additional targeting ligands efficacious in vivo including native hGLP1(7-36)NH2. Variation of the carrier peptide also shed some light on the dramatic impact of subtle sequence differences on the corresponding ASO conjugate performance in vivo, an area which clearly warrant further investigations. We have confirmed the remarkable potential of GLP1R agonist conjugation for the delivery of ASOs to pancreatic beta cell by effectively knocking down islet amyloid polypeptide (IAPP) mRNA, a potential proapoptotic target, in mice.

Comparative quantitative systems pharmacology modeling of anti-PCSK9 therapeutic modalities in hypercholesterolemia.

Since the discovery of proprotein convertase subtilisin/kexin type 9 (PCSK9) as an attractive target in the treatment of hypercholesterolemia, multiple anti-PCSK9 therapeutic modalities have been pursued in drug development. The objective of this research is to set the stage for the quantitative benchmarking of two anti-PCSK9 pharmacological modality classes, monoclonal antibodies (mAbs) and small interfering RNA (siRNA). To this end, we developed an integrative mathematical model of lipoprotein homeostasis describing the dynamic interplay between PCSK9, LDL-cholesterol (LDL-C), VLDL-cholesterol, HDL-cholesterol (HDL-C), apoB, lipoprotein a [Lp(a)], and triglycerides (TGs). We demonstrate that LDL-C decreased proportionally to PCSK9 reduction for both mAb and siRNA modalities. At marketed doses, however, treatment with mAbs resulted in an additional ∼20% LDL-C reduction compared with siRNA. We further used the model as an evaluation tool and determined that no quantitative differences were observed in HDL-C, Lp(a), TG, or apoB responses, suggesting that the disruption of PCSK9 synthesis would provide no additional effects on lipoprotein-related biomarkers in the patient segment investigated. Predictive model simulations further indicate that siRNA therapies may reach reductions in LDL-C levels comparable to those achieved with mAbs if the current threshold of 80% PCSK9 inhibition via siRNA could be overcome.

Clinical safety, tolerability, pharmacokinetics and effects on urinary electrolyte excretion of AZD9977, a novel, selective mineralocorticoid receptor modulator.

AIMS: AZD9977 is the first mineralocorticoid receptor modulator in clinical development exerting similar organ protection as eplerenone with minimal urinary electrolyte effects in preclinical studies. The aim was to perform the initial clinical assessment of AZD9977. METHODS: A first-in-human trial explored doses from 5 to 1200 mg. To study effects on urinary electrolyte excretion an additional randomized placebo controlled cross-over four-period clinical trial was performed. Twenty-three healthy volunteers were administered fludrocortisone alone or in combination with AZD9977, eplerenone or both. AZD9977/eplerenone combination was given to assess if AZD9977 can attenuate eplerenone induced natriuresis. RESULTS: AZD9977 at doses from 5 to 1200 mg was safe and well tolerated and pharmacokinetics were compatible with further development. AZD9977 exhibited similar effects on urinary ln [Na+ ]/[K+ ] as eplerenone when using fludrocortisone as mineralocorticoid receptor agonist, and the combination had an additive effect on ln [Na+ K+ ]. CONCLUSIONS: The results in man contradict the results in rodent models driven by aldosterone, in which AZD9977 has minimal electrolyte effects. Future clinical studies with AZD9977 should be performed in presence of endogenous or exogenous aldosterone to assess potential benefit of AZD9977 in patients.

Evaluation of pharmacokinetic and pharmacodynamic profiles of liposomes for the cell type-specific delivery of small molecule drugs.

Liposome-based drug formulations represent an exciting avenue of research as they increase efficacy to toxicity ratios. Current formulations rely on passive accumulation to the disease site where drug is taken up by the cells. Ligand mediated targeting increases the net accumulation of liposomes, however, an unexplored benefit is to potentially refine pharmacodynamics (PD) of a drug specifically to different cell types within diseased tissue. As a model system, we engineered cardiomyocyte- (I-1) and endothelial-targeted (B-40) liposomes to carry a VEGFR2 inhibitor (PTK787), and examined the effect of cell type-specific delivery on both pharmacokinetics (PK) and PD. Neovascularization in post-myocardial infarction was significantly reduced by B-40 liposomes loaded with PTK787 as compared to animals injected with I-1 liposomes, and profoundly more as compared to free PTK787. This study thus shows that the intraorgan targeting of drugs through cell type-specific delivery holds substantial promise towards lowering the minimal efficacious dose administered systemically.

Oral Drug Dosing After Gastric Bypass and Diet-Induced Weight Loss: Simpler Than We Think? Lessons Learned From the COCKTAIL Study.

This article summarizes the lessons learned from the COCKTAIL study: an open, three-armed, single-center study including patients with obesity scheduled for treatment with Roux-en-Y gastric bypass (RYGB) or nonsurgical calorie restriction, and a normal- to overweight control group. The clinical implications of the results from multiple peer-reviewed articles describing the effects of RYGB, severe caloric restriction, weight loss, and type 2 diabetes on the in vivo activity and protein expression of drug-metabolizing enzymes (cytochrome P450 (CYP) 1A2, 2C9, 2C19, and 3A) and transporters (DMETs; organic anion-transporting polypeptide (OATP) 1B1 and P-glycoprotein (P-gp)) are discussed in the perspective of three clinically relevant questions: (1) How should clinicians get the dose right in patients after RYGB? (2) Will drug disposition in patients with obesity be normalized after successful weight loss? (3) Are dose adjustments needed according to obesity and diabetes status? Overall, RYGB seems to have a lower impact on drug disposition than previously assumed, but clinicians should pay close attention to drugs with a narrow therapeutic range or where a high maximum drug concentration may be problematic. Whether obesity-related alterations of DMETs normalize with substantial weight loss depends on the DMET in question. Obesity and diabetes downregulate the in vivo activity of CYP2C19 and CYP3A (only obesity) but whether substrate drugs should be dose adjusted is also dependent on other factors that influence clearance, that is, liver blood flow and protein binding. Finally, we recommend frequent and individualized follow-up due to high inter- and intraindividual variability in these patients, particularly following RYGB.

Digoxin Pharmacokinetics in Patients with Obesity Before and After a Gastric Bypass or a Strict Diet Compared with Normal Weight Individuals.

BACKGROUND AND OBJECTIVE: Several drugs on the market are substrates for P-glycoprotein (P-gp), an efflux transporter highly expressed in barrier tissues such as the intestine. Body weight, weight loss, and a Roux-en-Y gastric bypass (RYGB) may influence P-gp expression and activity, leading to variability in the drug response. The objective of this study was therefore to investigate digoxin pharmacokinetics as a measure of the P-gp phenotype in patients with obesity before and after weight loss induced by an RYGB or a strict diet and in normal weight individuals. METHODS: This study included patients with severe obesity preparing for an RYGB (n = 40) or diet-induced weight loss (n = 40) and mainly normal weight individuals scheduled for a cholecystectomy (n = 18). Both weight loss groups underwent a 3-week low-energy diet (<1200 kcal/day) followed by an additional 6 weeks of <800 kcal/day induced by an RYGB (performed at week 3) or a very-low-energy diet. Follow-up time was 2 years, with four digoxin pharmacokinetic investigations at weeks 0, 3, and 9, and year 2. Hepatic and jejunal P-gp levels were determined in biopsies obtained from the patients undergoing surgery. RESULTS: The RYGB group and the diet group had a comparable weight loss in the first 9 weeks (13 ± 2.3% and 11 ± 3.6%, respectively). During this period, we observed a minor increase (16%) in the digoxin area under the concentration-time curve from zero to infinity in both groups: RYGB: 2.7 µg h/L [95% confidence interval (CI) 0.67, 4.7], diet: 2.5 µg h/L [95% CI 0.49, 4.4]. In the RYGB group, we also observed that the time to reach maximum concentration decreased after surgery: from 1.0 ± 0.33 hours at week 3 to 0.77 ± 0.08 hours at week 9 (-0.26 hours [95% CI -0.47, -0.05]), corresponding to a 25% reduction. Area under the concentration-time curve from zero to infinity did not change long term (week 0 to year 2) in either the RYGB (1.1 µg h/L [-0.94, 3.2]) or the diet group (0.94 µg h/L [-1.2, 3.0]), despite a considerable difference in weight loss from baseline (RYGB: 30 ± 7%, diet: 3 ± 6%). At baseline, the area under the concentration-time curve from zero to infinity was -5.5 µg h/L [95% CI -8.5, -2.5] (-26%) lower in patients with obesity (RYGB plus diet) than in normal weight individuals scheduled for a cholecystectomy. Further, patients undergoing an RYGB had a 0.05 fmol/µg [95% CI 0.00, 0.10] (29%) higher hepatic P-gp level than the normal weight individuals. CONCLUSIONS: Changes in digoxin pharmacokinetics following weight loss induced by a pre-operative low-energy diet and an RYGB or a strict diet (a low-energy diet plus a very-low-energy diet) were minor and unlikely to be clinically relevant. The lower systemic exposure of digoxin in patients with obesity suggests that these patients may have increased biliary excretion of digoxin possibly owing to a higher expression of P-gp in the liver.

Gastric Bypass vs Diet and Cardiovascular Risk Factors: A Nonrandomized Controlled Trial.

Importance: Roux-en-Y gastric bypass (RYGB) is associated with reduced cardiovascular (CV) risk factors, morbidity, and mortality. Whether these effects are specifically induced by the surgical procedure or the weight loss is unclear. Objective: To compare 6-week changes in CV risk factors in patients with obesity undergoing matching caloric restriction and weight loss by RYGB or a very low-energy diet (VLED). Design, Setting, and Participants: This nonrandomized controlled study (Impact of Body Weight, Low Calorie Diet, and Gastric Bypass on Drug Bioavailability, Cardiovascular Risk Factors, and Metabolic Biomarkers [COCKTAIL]) was conducted at a tertiary care obesity center in Norway. Participants were individuals with severe obesity preparing for RYGB or a VLED. Recruitment began February 26, 2015; the first patient visit was on March 18, 2015, and the last patient visit (9-week follow-up) was on August 9, 2017. Data were analyzed from April 30, 2021, through June 29, 2023. Interventions: VLED alone for 6 weeks or VLED for 6 weeks after RYGB; both interventions were preceded by 3-week LED. Main Outcomes and Measures: Between-group comparisons of 6-week changes in CV risk factors. Results: Among 78 patients included in the analyses, the mean (SD) age was 47.5 (9.7) years; 51 (65%) were women, and 27 (35%) were men. Except for a slightly higher mean (SD) body mass index of 44.5 (6.2) in the RYGB group (n = 41) vs 41.9 (5.4) in the VLED group (n = 37), baseline demographic and clinical characteristics were similar between groups. Major atherogenic blood lipids (low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, apolipoprotein B, lipoprotein[a]) were reduced after RYGB in comparison with VLED despite a similar fat mass loss. Mean between-group differences were -17.7 mg/dL (95% CI, -27.9 to -7.5), -17.4 mg/dL (95% CI, -29.8 to -5.0) mg/dL, -9.94 mg/dL (95% CI, -15.75 to -4.14), and geometric mean ratio was 0.55 U/L (95% CI, 0.42 to 0.72), respectively. Changes in glycemic control and blood pressure were similar between groups. Conclusions and Relevance: This study found that clinically meaningful reductions in major atherogenic blood lipids were demonstrated after RYGB, indicating that RYGB may reduce CV risk independent of weight loss. Trial Registration: ClinicalTrials.gov Identifier: NCT02386917.

Population pharmacokinetic modeling and deconvolution of enantioselective absorption of eflornithine in the rat.

Enantioselective pharmacokinetics and absorption of eflornithine in the rat was investigated using population pharmacokinetic modeling and a modified deconvolution method. Bidirectional permeability of L- and D-eflornithine was investigated in Caco-2 cells. The rat was administered racemic eflornithine hydrochloride as a single oral dose [40-3,000 mg/kg bodyweight (BW)] or intravenously (IV) (100-2,700 mg/kg BW infused over 60-400 min). Serial arterial blood samples were collected and L- and D-eflornithine were quantitated with a previously published chiral bioanalysis method. The D:L concentration ratio was determined in rat faeces. Intravenous L-and D-eflornithine plasma concentration-time data was analyzed using population pharmacokinetic modeling and described with a 3-compartment pharmacokinetic model with saturable binding to one of the peripheral compartments. Oral plasma concentration-time data was analyzed using a modified deconvolution method accounting for nonlinearities in the eflornithine pharmacokinetics. Clearance was similar for both enantiomers (3.36 and 3.09 mL/min). Oral bioavailability was estimated by deconvolution at 30 and 59% for L- and D-eflornithine. The D:L concentration ratio in feces was 0.49 and the Caco-2 cell permeability was similar for both enantiomers (6-10 × 10(-8) cm/s) with no evident involvement of active transport or efflux. The results presented here suggest that the difference in the bioavailability between eflornithine enantiomers is caused by a stereoselective difference in extent rather than rate of absorption. The presented modified deconvolution method made it possible to account for the non-linear component in the suggested three-compartment pharmacokinetic model thus rapidly estimating eflornithine oral bioavailability.

A modeling approach for compounds affecting body composition.

Body composition and body mass are pivotal clinical endpoints in studies of welfare diseases. We present a combined effort of established and new mathematical models based on rigorous monitoring of energy intake (EI) and body mass in mice. Specifically, we parameterize a mechanistic turnover model based on the law of energy conservation coupled to a drug mechanism model. Key model variables are fat-free mass (FFM) and fat mass (FM), governed by EI and energy expenditure (EE). An empirical Forbes curve relating FFM to FM was derived experimentally for female C57BL/6 mice. The Forbes curve differs from a previously reported curve for male C57BL/6 mice, and we thoroughly analyse how the choice of Forbes curve impacts model predictions. The drug mechanism function acts on EI or EE, or both. Drug mechanism parameters (two to three parameters) and system parameters (up to six free parameters) could be estimated with good precision (coefficients of variation typically <20 % and not greater than 40 % in our analyses). Model simulations were done to predict the EE and FM change at different drug provocations in mice. In addition, we simulated body mass and FM changes at different drug provocations using a similar model for man. Surprisingly, model simulations indicate that an increase in EI (e.g. 10 %) was more efficient than an equal lowering of EI. Also, the relative change in body mass and FM is greater in man than in mouse at the same relative change in either EI or EE. We acknowledge that this assumes the same drug mechanism impact across the two species. A set of recommendations regarding the Forbes curve, vehicle control groups, dual action on EI and loss, and translational aspects are discussed. This quantitative approach significantly improves data interpretation, disease system understanding, safety assessment and translation across species.

Proteome deconvolution of liver biopsies reveals hepatic cell composition as an important marker of fibrosis.

Human liver tissue is composed of heterogeneous mixtures of different cell types and their cellular stoichiometry can provide information on hepatic physiology and disease progression. Deconvolution algorithms for the identification of cell types and their proportions have recently been developed for transcriptomic data. However, no method for the deconvolution of bulk proteomics data has been presented to date. Here, we show that proteomes, which usually contain less data than transcriptomes, can provide useful information for cell type deconvolution using different algorithms. We demonstrate that proteomes from defined mixtures of cell lines, isolated primary liver cells, and human liver biopsies can be deconvoluted with high accuracy. In contrast to transcriptome-based deconvolution, liver tissue proteomes also provided information about extracellular compartments. Using deconvolution of proteomics data from liver biopsies of 56 patients undergoing Roux-en-Y gastric bypass surgery we show that proportions of immune and stellate cells correlate with inflammatory markers and altered composition of extracellular matrix proteins characteristic of early-stage fibrosis. Our results thus demonstrate that proteome deconvolution can be used as a molecular microscope for investigations of the composition of cell types, extracellular compartments, and for exploring cell-type specific pathological events. We anticipate that these findings will allow the refinement of retrospective analyses of the growing number of proteome datasets from various liver disease states and pave the way for AI-supported clinical and preclinical diagnostics.

Neither Gastric Bypass Surgery Nor Diet-Induced Weight-Loss Affect OATP1B1 Activity as Measured by Rosuvastatin Oral Clearance.

INTRODUCTION: Rosuvastatin pharmacokinetics is mainly dependent on the activity of hepatic uptake transporter OATP1B1. In this study, we aimed to investigate and disentangle the effect of Roux-en-Y gastric bypass (RYGB) and weight loss on oral clearance (CL/F) of rosuvastatin as a measure of OATP1B1-activity. METHODS: Patients with severe obesity preparing for RYGB (n = 40) or diet-induced weight loss (n = 40) were included and followed for 2 years, with four 24-hour pharmacokinetic investigations. Both groups underwent a 3-week low-energy diet (LED; < 1200 kcal/day), followed by RYGB or a 6-week very-low-energy diet (VLED; < 800 kcal/day). RESULTS: A total of 80 patients were included in the RYGB group (40 patients) and diet-group (40 patients). The weight loss was similar between the groups following LED and RYGB. The LED induced a similar (mean [95% CI]) decrease in CL/F in both intervention groups (RYGB: 16% [0, 31], diet: 23% [8, 38]), but neither induced VLED resulted in any further changes in CL/F. At Year 2, CL/F had increased by 21% from baseline in the RYGB group, while it was unaltered in the diet group. Patients expressing the reduced function SLCO1B1 variants (c.521TC/CC) showed similar changes in CL/F over time compared with patients expressing the wild-type variant. CONCLUSIONS: Neither body weight, weight loss nor RYGB per se seem to affect OATP1B1 activity to a clinically relevant degree. Overall, the observed changes in rosuvastatin pharmacokinetics were minor, and unlikely to be of clinical relevance.

Population Pharmacodynamic Modeling of Eflornithine-Based Treatments Against Late-Stage Gambiense Human African Trypanosomiasis and Efficacy Predictions of L-eflornithine-Based Therapy.

Eflornithine is a recommended treatment against late-stage gambiense human African trypanosomiasis, a neglected tropical disease. Standard dosing of eflornithine consists of repeated intravenous infusions of a racemic mixture of L- and D-eflornithine. Data from three clinical studies, (i) eflornithine intravenous monotherapy, (ii) nifurtimox-eflornithine combination therapy, and (iii) eflornithine oral monotherapy, were pooled and analyzed using a time-to-event pharmacodynamic modeling approach, supported by in vitro activity data of the individual enantiomers. Our aim was to assess (i) the efficacy of the eflornithine regimens in a time-to-event analysis and (ii) the feasibility of an L-eflornithine-based therapy integrating clinical and preclinical data. A pharmacodynamic time-to-event model was used to estimate the total dose of eflornithine, associated with 50% reduction in baseline hazard, when administered as monotherapy or in the nifurtimox-eflornithine combination therapy. The estimated total doses were 159, 60 and 291 g for intravenous eflornithine monotherapy, nifurtimox-eflornithine combination therapy and oral eflornithine monotherapy, respectively. Simulations suggested that L-eflornithine achieves a higher predicted median survival, compared to when racemate is administered, as treatment against late-stage gambiense human African trypanosomiasis. Our findings showed that oral L-eflornithine-based monotherapy would not result in adequate efficacy, even at high dose, and warrants further investigations to assess the potential of oral L-eflornithine-based treatment in combination with other treatments such as nifurtimox. An all-oral eflornithine-based regimen would provide easier access to treatment and reduce burden on patients and healthcare systems in gambiense human African trypanosomiasis endemic areas. Graphical abstract.

Drug Disposition Protein Quantification in Matched Human Jejunum and Liver From Donors With Obesity.

Mathematical models, such as physiologically-based pharmacokinetic models, are used to predict, for example, drug disposition and toxicity. However, populations differ in the abundance of proteins involved in these processes. To improve the building and refinement of such models, they must take into account these interindividual variabilities. In this study, we used global proteomics to characterize the protein composition of jejunum and liver from 37 donors with obesity enrolled in the COCKTAIL study. Liver protein levels from the 37 donors were further compared with those from donors without obesity. We quantified thousands of proteins and could present the expression of several drug-metabolizing enzymes, for the first time, in jejunum, many of which belong to the cytochrome P450 (CYP) (e.g., CYP2U1) and the amine oxidase (flavin-containing) (e.g., monoamine oxidase A (MAOA)) families. Although we show that many metabolizing enzymes had greater expression in liver, others had higher expression in jejunum (such as, MAOA and CES2), indicating the role of the small intestine in extrahepatic drug metabolism. We further show that proteins involved in drug disposition are not correlated in the two donor-matched tissues. These proteins also do not correlate with physiological factors such as body mass index, age, and inflammation status in either tissue. Furthermore, the majority of these proteins are not differently expressed in donors with or without obesity. Nonetheless, interindividual differences were considerable, with implications for personalized prediction models and systems pharmacology.

Impact of type 2 diabetes on in vivo activities and protein expressions of cytochrome P450 in patients with obesity.

Previous studies have not accounted for the close link between type 2 diabetes mellitus (T2DM) and obesity when investigating the impact of T2DM on cytochrome P450 (CYP) activities. The aim was to investigate the effect of T2DM on in vivo activities and protein expressions of CYP2C19, CYP3A, CYP1A2, and CYP2C9 in patients with obesity. A total of 99 patients from the COCKTAIL study (NCT02386917) were included in this cross-sectional analysis; 29 with T2DM and obesity (T2DM-obesity), 53 with obesity without T2DM (obesity), and 17 controls without T2DM and obesity (controls). CYP activities were assessed after the administration of a cocktail of probe drugs including omeprazole (CYP2C19), midazolam (CYP3A), caffeine (CYP1A2), and losartan (CYP2C9). Jejunal and liver biopsies were also obtained to determine protein concentrations of the respective CYPs. CYP2C19 activity and jejunal CYP2C19 concentration were 63% (-0.39 [95% CI: -0.82, -0.09]) and 40% (-0.09 fmol/µg protein [95% CI: -0.18, -0.003]) lower in T2DM-obesity compared with the obesity group, respectively. By contrast, there were no differences in the in vivo activities and protein concentrations of CYP3A, CYP1A2, and CYP2C9. Multivariable regression analyses also indicated that T2DM was associated with interindividual variability in CYP2C19 activity, but not CYP3A, CYP1A2, and CYP2C9 activities. The findings indicate that T2DM has a significant downregulating impact on CYP2C19 activity, but not on CYP3A, CYP1A2, and CYP2C9 activities and protein concentrations in patients with obesity. Hence, the effect of T2DM seems to be isoform-specific.

A case-study of model-informed drug development of a novel PCSK9 anti sense oligonucleotide. Part 1: First time in man to phase II.

Here, we show model-informed drug development (MIDD) of a novel antisense oligonucleotide, targeting PCSK9 for treatment of hypocholesteremia. The case study exemplifies use of MIDD to analyze emerging data from an ongoing first-in-human study, utility of the US Food and Drug Administration MIDD pilot program to accelerate timelines, innovative use of competitor data to set biomarker targets, and use of MIDD to optimize sample size and dose selection, as well as to accelerate and de-risk a phase IIb study. The focus of the case-study is on the cross-functional collaboration and other key MIDD enablers that are critical to maximize the value of MIDD, rather than the technical application of MIDD.

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.

Feedback modeling of non-esterified fatty acids in rats after nicotinic acid infusions.

A feedback model was developed to describe the tolerance and oscillatory rebound seen in non-esterified fatty acid (NEFA) plasma concentrations following intravenous infusions of nicotinic acid (NiAc) to male Sprague-Dawley rats. NiAc was administered as an intravenous infusion over 30 min (0, 1, 5 or 20 µmol kg(-1) of body weight) or over 300 min (0, 5, 10 or 51 µmol kg(-1) of body weight), to healthy rats (n = 63), and serial arterial blood samples were taken for measurement of NiAc and NEFA plasma concentrations. Data were analyzed using nonlinear mixed effects modeling (NONMEM). The disposition of NiAc was described by a two-compartment model with endogenous turnover rate and two parallel capacity-limited elimination processes. The plasma concentration of NiAc was driving NEFA (R) turnover via an inhibitory drug-mechanism function acting on the formation of NEFA. The NEFA turnover was described by a feedback model with a moderator distributed over a series of transit compartments, where the first compartment (M (1)) inhibited the formation of R and the last compartment (M ( N )) stimulated the loss of R. All processes regulating plasma NEFA concentrations were assumed to be captured by the moderator function. The potency, IC (50), of NiAc was 45 nmol L(-1), the fractional turnover rate k ( out ) was 0.41 L mmol(-1) min(-1) and the turnover rate of moderator k ( tol ) was 0.027 min(-1). A lower physiological limit of NEFA was modeled as a NiAc-independent release (k ( cap )) of NEFA into plasma and was estimated to 0.032 mmol L(-1) min(-1). This model can be used to provide information about factors that determine the time-course of NEFA response following different modes, rates and routes of administration of NiAc. The proposed model may also serve as a preclinical tool for analyzing and simulating drug-induced changes in plasma NEFA concentrations after treatment with NiAc or NiAc analogues.

Comparisons of basic target-mediated drug disposition (TMDD) and ligand facilitated target removal (LFTR).

In the well-known model for basic Target-Mediated Drug Disposition (TMDD), drug binds to the target and the resulting drug-target complex is removed by a first order process, leading to loss of both drug and target. In the present note we study what happens when, instead, drug is returned to the free drug pool so that it can a new target molecule. What results is a mechanism in which the drug, here referred to as the ligand, facilitates the removal of the target,and then returns to the free ligand pool. Accordingly the process will be referred to as Ligand-Facilitated Target Removal (LFTR). It is shown through simulations and mathematical analysis how the two models differ and how their signature profiles typically appear. We also derive a useful parameter of both models, the in vivo potency EC50 (L50) which contains both ligand-target binding properties (kon,koff), target turnover (kdeg) and ligand-target complex kinetics (ke(RL)). Thus, this parameter contains a conglomerate of properties and is therefore potentially more informative about relevant (clinical) exposure than the binding affinity (Kd) alone. The derived potency parameter EC50 may therefore be used as a more robust ranking parameter among small and large drug molecules in drug discovery. Subsequently the LFTR model is applied to experimentally obtained literature data and the relevant parameters are estimated.