Common gastrointestinal drug-drug interactions in geriatrics and the importance of careful planning

The real-world safety profile of pemetrexed and platinum with or without pembrolizumab: insights from a comparative analysis of FAERS database

BACKGROUND

Lung cancer (LC) is a leading cause of cancer-related mortality worldwide. The combination of immune checkpoint inhibitors (ICIs) with chemotherapy significantly extends survival but increases the risk of treatment-related toxicity. To explore the impact of adding pembrolizumab to pemetrexed and platinum on treatment-related toxicity, this study utilized the FDA Adverse Event Reporting System (FAERS) to assess the safety of pemetrexed and platinum with or without pembrolizumab in LC patients.

METHODS

We collected data from FAERS database between the second quarter of 2017 and the third quarter of 2024. Disproportionality analysis was conducted using the Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and Multi-Item Gamma Poisson Shrinker (MGPS). Additionally, comparative analysis was performed using the ROR method.

RESULTS

Among LC patients receiving chemotherapy alone (pemetrexed + platinum) and combination therapy (pembrolizumab + pemetrexed + platinum), adverse event (AE) reports were 2871 and 5443 cases, respectively. Compared to chemotherapy alone, combination therapy was associated with a higher risk of renal and urinary disorders, hepatobiliary disorders, and interstitial lung disease (ILD), pneumonitis and other AEs. Subgroup analysis revealed that gender and age may be influential factors in the occurrence of AEs. Combination therapy prolonged the time to onset of AEs.

CONCLUSIONS

In the real world, combination therapy increases the risk of certain AEs, particularly in specific patient subgroups. These findings emphasize the importance of personalized treatment strategies and AE monitoring, particularly during the first three months of therapy.

Gastrointestinal Motility Function and Dysfunction in the Elderly Patient: What Are the Effects of Aging?

Background

The prevalence of neurogastroenterological diseases, i.e., disorders of gut brain interaction, has increased over the last decades. Altered gastrointestinal (GI) motility is a key feature of this group of diseases and is affecting all anatomical segments of the GI tract, ranging from swallowing disorders to fecal incontinence. Considering the ongoing demographic transformation in developed countries worldwide, it is highly relevant to understand the age-dependency of motility disorders per se and its pathophysiological mechanisms with a special focus on neurodegeneration. This review summarizes the most relevant findings and open research questions in the field of age-dependent changes in GI motility with a strong focus on studies performed on humans or with biological material obtained from humans.

Summary

While the basic function of the GI tract including motility in most of its segments is largely unaltered by aging per se, there is clear evidence supporting an age-dependent increase in the prevalence of constipation and fecal incontinence, the latter mainly affecting women. When, however, the large percentage of elderly patients suffering from frequent chronic diseases such as diabetes, Parkinson's disease, or cerebrovascular disease are included, a clear increase in "secondary" motility disorders also affecting the esophagus or the stomach is evident. Studies regarding the pathophysiology of geriatric dysmotility are often limited by the heterogenous clinical history of the studied patients and by coincident impairments of interoceptive sensory function. However, a loss in the number of cholinergic neurons together with changes in the number of interstitial cells of Cajal, certain subtypes of enteric glia, changes in immune cell function, and changes in the endocrine signaling throughout the GI tract have been reported.

Key Messages

The overall prevalence of swallowing disorders, impaired gastric emptying, constipation and fecal incontinence is high among elderly patients. The pathophysiology most likely includes a variety of factors ranging from degeneration of enteric neurons and the non-neuronal cell populations involved in GI motility up to age-dependent metabolic and neuroendocrine changes and dietary factors. Deciphering the effects of "healthy aging" but also of the numerous typical chronic diseases of the elderly on GI motility is an ongoing challenge and prerequisite for improving patients' medical care and quality of life.

Pharmacokinetic considerations for drugs that treat diarrhea-predominant irritable bowel syndrome: what's new?

INTRODUCTION

Irritable bowel syndrome (IBS), which presents a significant healthcare and socioeconomic burden, is one of the main issues in the field of therapy. Hence, it is imperative to tackle this matter by evaluating the safety and efficacy of the available treatments and determining the ideal approach for each patient.

AREAS COVERED

We reviewed the pharmacokinetics and safety of pharmacologic interventions administered in diarrhea-predominant IBS (IBS-D) patients. PubMed, Google Scholar and the USFDA databases were searched up to November 2023 to include all updated information on eluxadoline, alosetron, and rifaximin.

EXPERT OPINION

The most effective way to treat IBS-D is to focus on managing the most common symptoms. However, healthcare providers face a challenge when it comes to identifying the right treatment for each patient, and the root cause of this is the diversity of IBS-D population. Studies have shown that there are differences in how men and women metabolize drugs, which may lead to gender-specific adverse reactions. Women tend to have higher drug concentrations in their bloodstream and take longer to eliminate them. Therefore, healthcare providers may need to reduce the dosage for female patients. Integrating IBS care into sustainable development efforts can indirectly contribute to achieving SDGs and promote health and well-being for all.

In vitro safety signals for potential clinical development of the anti-inflammatory pregnane X receptor agonist FKK6

Based on the mimicry of microbial metabolites, functionalized indoles were demonstrated as the ligands and agonists of the pregnane X receptor (PXR). The lead indole, FKK6, displayed PXR-dependent protective effects in DSS-induced colitis in mice and in vitro cytokine-treated intestinal organoid cultures. Here, we report on the initial in vitro pharmacological profiling of FKK6. FKK6-PXR interactions were characterized by hydrogen-deuterium exchange mass spectrometry. Screening FKK6 against potential cellular off-targets (G protein-coupled receptors, steroid and nuclear receptors, ion channels, and xenobiotic membrane transporters) revealed high PXR selectivity. FKK6 has poor aqueous solubility but was highly soluble in simulated gastric and intestinal fluids. A large fraction of FKK6 was bound to plasma proteins and chemically stable in plasma. The partition coefficient of FKK6 was 2.70, and FKK6 moderately partitioned into red blood cells. In Caco2 cells, FKK6 displayed high permeability (A-B: 22.8 × 10-6 cm.s-1) and no active efflux. These data are indicative of essentially complete in vivo absorption of FKK6. The data from human liver microsomes indicated that FKK6 is rapidly metabolized by cytochromes P450 (t1/2 5 min), notably by CYP3A4. Two oxidized FKK6 derivatives, including DC73 (N6-oxide) and DC97 (C19-phenol), were detected, and these metabolites had 5-7 × lower potency as PXR agonists than FKK6. This implies that despite high intestinal absorption, FKK6 is rapidly eliminated by the liver, and its PXR effects are predicted to be predominantly in the intestines. In conclusion, the PXR ligand and agonist FKK6 has a suitable pharmacological profile supporting its potential preclinical development.

Regulation of PXR in drug metabolism: chemical and structural perspectives

INTRODUCTION

Pregnane X receptor (PXR) is a master xenobiotic sensor that transcriptionally controls drug metabolism and disposition pathways. PXR activation by pharmaceutical drugs, natural products, environmental toxins, etc. may decrease drug efficacy and increase drug-drug interactions and drug toxicity, indicating a therapeutic value for PXR antagonists. However, PXR's functions in physiological events, such as intestinal inflammation, indicate that PXR activators may be useful in certain disease contexts.

AREAS COVERED

We review the reported roles of PXR in various physiological and pathological processes including drug metabolism, cancer, inflammation, energy metabolism, and endobiotic homeostasis. We then highlight specific cellular and chemical routes that modulate PXR activity and discuss the functional consequences. Databases searched and inclusive dates: PubMed, 1 January 1980 to 10 January 2024.

EXPERT OPINION

Knowledge of PXR's drug metabolism function has helped drug developers produce small molecules without PXR-mediated metabolic liabilities, and further understanding of PXR's cellular functions may offer drug development opportunities in multiple disease settings.