Severity of coeliac disease and clinical management study when using a CYP3A4 metabolised medication: a phase I pharmacokinetic study

Guidelines for best practices in monitoring established coeliac disease in adult patients

Coeliac disease (CeD) is an immunological disease triggered by the consumption of gluten contained in food in individuals with a genetic predisposition. Diagnosis is based on the presence of small bowel mucosal atrophy and circulating autoantibodies (anti-type 2 transglutaminase antibodies). After diagnosis, patients follow a strict, life-long gluten-free diet. Although the criteria for diagnosis of this disease are well defined, the monitoring phase has been studied less and there is a lack of specific guidelines for this phase. To develop a set of clinical guidelines for CeD monitoring, we followed the Grading of Recommendations Assessment, Development and Evaluation methodology. Statements and recommendations with the level of evidence were developed and approved by the working group, which comprised gastroenterologists, pathologists, dieticians and biostatisticians. The proposed guidelines, endorsed by the North American and European coeliac disease scientific societies, make recommendations for best practices in monitoring patients with CeD based on the available evidence. The evidence level is low for many topics, suggesting that further research in specific aspects of CeD would be valuable. In conclusion, the present guidelines support clinicians in improving CeD treatment and follow-up and highlight novel issues that should be considered in future studies.

Physiologically based pharmacokinetic modeling for development and applications of a virtual celiac disease population using felodipine as a model drug

In celiac disease (CeD), gastrointestinal CYP3A4 abundance and morphology is affected by the severity of disease. Therefore, exposure to CYP3A4 substrates and extent of drug interactions is altered. A physiologically-based pharmacokinetic (PBPK) population for different severities of CeD was developed. Gastrointestinal physiology parameters, such as luminal pH, transit times, morphology, P-gp, and CYP3A4 expression were included in development of the CeD population. Data on physiological difference between healthy and CeD subjects were incorporated into the model as the ratio of celiac to healthy. A PBPK model was developed and verified for felodipine extended-release tablet in healthy volunteers (HVs) and then utilized to verify the CeD populations. Plasma concentration-time profile and PK parameters were predicted and compared against those observed in both groups. Sensitivity analysis was carried out on key system parameters in CeD to understand their impact on drug exposure. For felodipine, the predicted mean concentration-time profiles and 5th and 95th percentile intervals captured the observed profile and variability in the HV and CeD populations. Predicted and observed clearance was 56.9 versus 56.1 (L/h) in HVs. Predicted versus observed mean ± SD area under the curve for extended release felodipine in different severities of CeD were values of 14.5 ± 9.6 versus 14.4 ± 2.1, 14.6 ± 9.0 versus 17.2 ± 2.8, and 28.1 ± 13.5 versus 25.7 ± 5.0 (ng.h/mL), respectively. Accounting for physiology differences in a CeD population accurately predicted the PK of felodipine. The developed CeD population can be applied for determining the drug concentration of CYP3A substrates in the gut as well as for systemic levels, and for application in drug-drug interaction studies.

Severity of coeliac disease and clinical management study when using a non-metabolised medication: a phase I pharmacokinetic study

OBJECTIVE

The non-metabolised antihistamine fexofenadine has oral absorption resulting from transporter activity. Uptake by enterocyte organic anion transporting polypeptides and efflux by an ATP-binding cassette transporter (P-glycoprotein) are primary determinants. Coeliac disease-mediated lesions to the small intestinal mucosa may alter oral absorption of the drug probe, fexofenadine.

DESIGN

A phase I, open-label, single-dose, pharmacokinetic study SETTING: London, Ontario, Canada PARTICIPANTS: Patients with coeliac disease (n=41) with positive serology and healthy individuals (n=48).

MAIN OUTCOME MEASURES

Patients with coeliac disease-duodenal histology and oral fexofenadine pharmacokinetics within a 3-week period. Healthy individuals-oral fexofenadine pharmacokinetics with water and grapefruit juice.

RESULTS

Patients with coeliac disease were stratified by disease severity: Group A (n=15, normal), B+C (n=14, intraepithelial lymphocytosis with/without mild villous blunting) and D (n=12, moderate to severe villous blunting). Patients with coeliac disease in groups A, B+C and D and healthy individuals receiving water had similar fexofenadine AUC0-8 (2038±304, 2259±367, 2128±410, 1954±138 ng.h/mL; p>0.05; mean±SEM) and Cmax (440±73, 513±96, 523±104, 453±32 ng/mL; p>0.05), respectively. These four groups all had higher fexofenadine AUC0-8 (1063±59; p<0.01) and Cmax (253±18; p<0.05) compared with those for healthy individuals receiving grapefruit juice. Coeliac groups had a positive linear trend between disease severity and fexofenadine Tmax (2.0±0.3, 2.7±0.4, 3.1±0.5 hours; p<0.05).

CONCLUSIONS

Coeliac disease severity based on duodenal histopathology did not affect oral fexofenadine bioavailability. Increased Tmax suggested absorption distal to the duodenum (jejunum + ileum), where histology seems more normal which may be the key determinant. Patients with coeliac disease may not require consideration for alternative clinical drug management for a number of non-metabolised and transport-mediated medications.

Beta adrenergic antagonists and antianginal drugs

Beta adrenergic antagonists and antianginal drugs are used with the aim to ultimately decrease mortality and enable patients to lead an improved quality of life by avoidance of anginal episodes. Each class of medications used for this purpose have a variety of actual or potential side effects associated with their use. Side effects and drug interactions involving these medications are discussed in the following chapter. A special review is included that examines available evidence in the context of the current COVID-19 pandemic. Evidence presented should be used in the context of the patient populations described and may aid clinical decision making through avoidance or identification of actual or potential side effects. This review includes literature published from November 2019 to January 2021.

Molecular Biomarkers for Celiac Disease: Past, Present and Future

Celiac disease (CeD) is a complex immune-mediated disorder that is triggered by dietary gluten in genetically predisposed individuals. CeD is characterized by inflammation and villous atrophy of the small intestine, which can lead to gastrointestinal complaints, malnutrition, and malignancies. Currently, diagnosis of CeD relies on serology (antibodies against transglutaminase and endomysium) and small-intestinal biopsies. Since small-intestinal biopsies require invasive upper-endoscopy, and serology cannot predict CeD in an early stage or be used for monitoring disease after initiation of a gluten-free diet, the search for non-invasive biomarkers is ongoing. Here, we summarize current and up-and-coming non-invasive biomarkers that may be able to predict, diagnose, and monitor the progression of CeD. We further discuss how current and emerging techniques, such as (single-cell) transcriptomics and genomics, can be used to uncover the pathophysiology of CeD and identify non-invasive biomarkers.