The influence of age and sex on the clearance of cytochrome P450 3A substrates

Sex-Related Differences in Immunotherapy Toxicities: Insights into Dimorphic Responses

Significant sex-based differences exist in the immune system and antitumor immune responses, potentially leading to variations in both the efficacy and toxicity of anticancer immunotherapies. Women generally mount stronger innate and adaptive immune responses than men, which can result in more severe immune-related adverse events (irAEs) during treatments with immune checkpoint inhibitors (ICIs). However, the importance of sex dimorphism in the safety of cancer immunotherapy remains underexplored in clinical oncology, despite its profound implications for treatment outcomes. Our review highlights the critical influence of biological sex on pharmacokinetics, pharmacodynamics, and immune responses, shaping ICI efficacy and the prevalence, type, and severity of irAEs. Integrating sex as a critical variable in cancer treatment and clinical trial design is essential for personalizing therapeutic strategies, bridging existing knowledge gaps, and enhancing survival rates and quality of life for patients across genders.

Distribution Characteristics and Impacting Factors of Drug CYP Enzymes and Transporters in the Gastrointestinal Tract of Chinese Healthy Subjects

The abundance of drug metabolic enzymes (DMEs) and transporters (DTs) in the human gastrointestinal tract significantly affects xenobiotic exposure in the circulating system, the basis of these compounds acting on humans. However, accurately predicting individual exposure in healthy subjects remains challenging due to limited data on protein levels throughout the gastrointestinal tract within the same individuals and inadequate assessment of factors influencing these levels. Therefore, we conducted a clinical study to obtain biopsy samples from 8 different gastrointestinal segments in 24 healthy Chinese volunteers. Concurrently, blood and fecal samples were collected for genotypic analysis and fecal microbiota metagenomic sequencing. Using an optimized LC-MS/MS method, we quantified the absolute protein abundance of CYP2C9, CYP2C19, CYP2D6, CYP3A4, P-gp, and BCRP from the stomach to the colon. Our results revealed significant regional differences in protein expression: CYP3A4 was the most abundant in the small intestine, whereas CYP2C9 was predominantly found in the colon. CYP2D6 was primarily located in the ileum, while other DMEs/DTs showed higher concentrations in the jejunum. Meanwhile, the enzyme abundance in the small intestine and colon and the relative ratio of transporters in different regions to the jejunum were accurately calculated, providing valuable data for refining the physiological parameters in the virtual gastrointestinal tract of Chinese healthy population in PBBMs. Additionally, BMI, IBW, sex, age, genotype, and fecal microbiota were identified as critical factors influencing the protein levels of these DMEs/DTs throughout the gastrointestinal tract, with notable regional differences. Consequently, this study provides a unique foundation for understanding xenobiotic absorption in humans.

Pharmacokinetics, safety, and efficacy of daridorexant in Japanese subjects: Results from phase 1 and 2 studies

Daridorexant is a dual orexin receptor antagonist for the treatment of insomnia. We report results from the first two randomised, double-blind clinical studies of daridorexant in Japanese subjects. In the Phase 1 study, daridorexant (10, 25, 50 mg) or placebo were administered in the morning for 4 days in 24 young (mean age 26.9 years) and 24 older (mean age 69.7 years) healthy Japanese adults. Daridorexant reached a peak plasma concentration within 1.0 h across every dose and age group. For all doses, the mean plasma concentration of daridorexant showed a similar change between the age groups. Exposure parameters increased dose-dependently with minimal/no accumulation upon repeated dosing. The terminal half-life was ~8 h. In the Phase 2, four-period, four-way crossover study, 47 Japanese subjects (mean age 50.4 years) with insomnia disorder were randomised to receive four treatments (daridorexant 10, 25, 50 mg, placebo) during four treatment periods, each consisting of two treatment nights (5-12 day washout between treatment periods). Subjects continued their fourth treatment for 12 further days. A statistically significant dose-response relationship (multiple-comparison procedure-modelling, p < 0.0001) was found in the reduction of polysomnography-measured wake after sleep onset (WASO; primary endpoint) and latency to persistent sleep (secondary endpoint) from baseline to days 1/2. Statistically significant dose-response relationships were also observed for secondary subjective endpoints from baseline to days 1/2 (sWASO, latency to sleep onset). All daridorexant doses were well tolerated, with no treatment discontinuations and no next-morning residual effects. These results supported further investigation of daridorexant in Japanese patients with insomnia disorder.

Aging-Related CYP3A Functional Changes in Chinese Older Patients: New Findings from Model-Based Assessment of Amlodipine

Aging-related alterations in hepatic enzyme activity, particularly of the CYP3A, significantly impact drug efficacy and safety in older adults, making it essential to understand how aging affects CYP function for optimal drug therapy. The exogenous probe substrate method, a minimally invasive approach to assess liver metabolic enzyme activity in vivo, is effective in studying these changes. Amlodipine being extensively metabolized (> 90%) in the liver, primarily via cytochrome P450 enzyme CYP3A was selected as a probe to investigate and quantify the factors affecting the aging-related changes of CYP3A in the Chinese older population. Amlodipine concentration data were collected from an ongoing noninterventional clinical study conducted at Peking University Third Hospital. A physiologically-based pharmacokinetic modeling approach, grounded in population pharmacokinetic (PPK) analysis, was employed to physiologically quantify the aging-related changes in CYP3A function. A total of 132 amlodipine concentrations from 69 patients were obtained from the clinical study. PPK analysis shows that frailty phenotype but not age is a significant influence and frail patients have 37% greater plasma amlodipine exposure than nonfrail patients. This difference in CYP3A function may be attributed to a 63.2% lower CYP3A relative abundance in the frail patients, compared with that in the nonfrail patients. In the context of dose selection for older adults, focusing on frailty rather than chronological age should be recognized as a more relevant approach, because frailty might more accurately reflect the individual's biological age. Our study suggested a need to shift the research focus from chronological age to biological age.

3D spheroid HepaRG and fluorescent biphasic tracer for CYP3A4-mediated antibiotic interaction monitoring in sepsis

Cytochrome P450 3A4 (CYP3A4) is a crucial enzyme in the metabolism of xenobiotics, particularly in drug metabolism interactions (DDIs), making it a significant factor in clinical drug use. However, current assay techniques are both laborious and costly, making it difficult to construct a high-throughput monitoring method that can be used in conjunction with the clinic. This poses certain safety hazards for drug combination. Therefore, it is crucial to develop a synchronized monitoring method for the inhibition and induction of CYP3A4. In this study, we utilized 3D culture technology to develop a HepaRG cells spheroid model. The CYP450 and transporter expression, the albumin secretion, and urea synthesis capacity characteristics were analyzed. The NEN probe was utilized as a tracer molecule for CYP3A4. The fluorescence intensity of metabolites was characterized by laser confocal technique to determine the inhibition and expression of CYP3A4 in the HepaRG cell spheroid model by the antibiotics for sepsis. The results indicate that the HepaRG sphere model successfully possessed the physiological phenotype of the liver, which could be used for drug interaction monitoring. Through positive drug testing, NEN probe was able to achieve bidirectional characterization of CYP3A4 induction and inhibition. The monitoring method described in this paper was successfully applied to drug interaction monitoring of commonly used antibiotics in sepsis patients, which is a convenient and rapid monitoring method. The proposed method offers a new strategy for monitoring CYP3A4-mediated drug-drug interactions with a high-throughput assay, which will help to improve the safety of clinical drug combination.

Acute toxicity of chemotherapy in central nervous system germ cell tumour patients according to age

Background

SIOP-CNS-GCT-II European trial was opened for the treatment of patients of any age with central nervous system germ cell tumour (CNS-GCT). Four courses of pre-irradiation chemotherapy were delivered. The influence of patient age on chemotherapy related acute toxicity (CRAT) was assessed.

Methods

CRAT was analysed according to age-groups: children (aged ≤11 years), adolescents (aged 12-17 years), adults (aged ≥18 years) and to chemotherapy type: CarboPEI (alternating etoposide-carboplatin/etoposide-ifosfamide) for non-metastatic germinoma; PEI (cisplatin-etoposide-ifosfamide) for standard-risk non-germinomatous GCT (NGGCT); PEI and high-dose PEI (HD-PEI), for high-risk or poorly responsive NGGCTs.

Results

296 patients were assessable for CRAT: 105 children, 121 adolescents, 70 adults (max age: 41 years). Median cumulative doses/m² of chemotherapy were similar among age-groups. The proportion of germinoma over NGGCT (and accordingly use of CarboPEI chemotherapy) was higher in the adult groups (79%) versus the other two groups (62%). Delay in chemotherapy ≥7 days was noticed in 27%, 38%, and 19% of children, adolescents, and adults, respectively. Grade ≥3 haematological and non-haematological adverse events (AEs) were observed in 94%/31%, 97%/36%, and 77%/21% of children, adolescents, and adults, respectively. No toxic death was reported. Grade ≥3 AEs and delayed chemotherapies were significantly rarer in adults when compared with adolescents, even when adjusted on chemotherapy type: odds ratio: 0.1 [95%CI 0.02-0.4], and 0.2 [95%CI 0.1-0.4] in the group treated with CarboPEI.

Conclusion

Adult patients can be treated safely with a chemotherapy intensive protocol, with even less toxicity than that observed in adolescents. Further work is required to understand age-related differences regarding toxicity.

Cell senescence in liver diseases: pathological mechanism and theranostic opportunity

The liver is not oblivious to the passage of time, as ageing is a major risk factor for the development of acute and chronic liver diseases. Ageing produces alterations in all hepatic cells, affecting their phenotype and function and worsening the prognosis of liver disease. The ageing process also implies the accumulation of a cellular state characterized by a persistent proliferation arrest and a specific secretory phenotype named cellular senescence. Indeed, senescent cells have key roles in many physiological processes; however, their accumulation owing to ageing or pathological conditions contributes to the damage occurring in chronic diseases. The aim of this Review is to provide an updated description of the pathophysiological events in which hepatic senescent cells are involved and their role in liver disease progression. Finally, we discuss novel geroscience therapies that could be applied to prevent or improve liver diseases and age-mediated hepatic deregulations.

Central Nervous System Medications: Pharmacokinetic and Pharmacodynamic Considerations for Older Adults

Most drugs have not been evaluated in the older population. Recognizing physiological alterations associated with changes in drug disposition and with the ultimate effect, especially in central nervous system-acting drugs, is fundamental. While considering pharmacokinetics, it should be noted that the absorption of most drugs from the gastrointestinal tract does not change in advanced age. There are only few data about the effect of age on the transdermal absorption of medications such as fentanyl. Absorption from an intramuscular injection may be similar in older adults as in younger patients. The distribution of lipophilic drugs (such as diazepam) is increased owing to a relative increase in the percentage of body fat, causing drug accumulation and prolonged drug elimination following cessation. Phase I drug biotransformation is variably decreased in aging, impacting elimination, and hepatic drug clearance has been shown to decrease in older individuals by 10-40% for most drugs studied. Lower doses of phenothiazines, butyrophenones, atypical antipsychotics, antidepressants (citalopram, mirtazapine, and tricyclic antidepressants), and benzodiazepines (such as diazepam) achieve the same extent of exposure. For renally cleared drugs with no prior metabolism (such as gabapentin), the glomerular filtration rate appropriately estimates drug clearance. Important pharmacodynamic changes in older adults include an increased sedative effect of benzodiazepines at a given drug exposure, and a higher sensitivity to mu opiate receptor agonists and to opioid adverse effects. Artificial intelligence, physiologically based pharmacokinetic modeling and simulation, and concentration-effect modeling enabling a differentiation between the pharmacokinetic and the pharmacodynamic effects of aging might help to close some of the gaps in knowledge.

Closing the sex gap in cardiovascular mortality by achieving both horizontal and vertical equity

Addressing sex differences and disparities in coronary heart disease (CHD) involves achieving both horizontal and vertical equity in healthcare. Horizontal equity in the context of CHD means that both men and women with comparable health statuses should have equal access to diagnosis, treatment, and management of CHD. To achieve this, it is crucial to promote awareness among the general public about the signs and symptoms of CHD in both sexes, so that both women and men may seek timely medical attention. Women often face inequity in the treatment of cardiovascular disease. Current guidelines do not differ based on sex, but their applications based on gender do differ. Vertical equity means tailoring healthcare to allow equitable care for all. Steps towards achieving this include developing treatment protocols and guidelines that consider the unique aspects of CHD in women. It also requires implementing guidelines equally, when there is not sex difference rather than inequities in application of guideline directed care.

Pharmacokinetics, Pharmacodynamics, and Side Effects of Midazolam: A Review and Case Example

Midazolam, a short-acting benzodiazepine, is widely used to alleviate patient anxiety, enhance compliance, and aid in anesthesia. While its side effects are typically dose-dependent and manageable with vigilant perioperative monitoring, serious cardiorespiratory complications, including fatalities and permanent neurological impairment, have been documented. Prolonged exposure to benzodiazepines, such as midazolam, has been associated with neurological changes in infants. Despite attempts to employ therapeutic drug monitoring for optimal sedation dosing, its efficacy has been limited. Consequently, efforts are underway to identify alternative predictive markers to guide individualized dosing and mitigate adverse effects. Understanding these factors is crucial for determining midazolam's suitability for future administration, particularly after a severe adverse reaction. This article aims to elucidate the factors influencing midazolam's pharmacokinetics and pharmacodynamics, potentially leading to adverse events. Finally, a case study is presented to exemplify the complex investigation into the causative factors of midazolam-related adverse events.

Implications of Sex Differences on the Treatment Effectiveness in Heart Failure with Reduced Ejection Fraction Related to Clinical Endpoints and Quality of Life

PURPOSE OF THE REVIEW

This narrative review will emphasize the necessity for more female enrollment in heart failure (HF) trials and proposes future investigations regarding optimal dosages. Ultimately, a deeper understanding of the unique pathophysiology and medication responses in both men and women is crucial for effective HF management and may improve the quality of life in women.

RECENT FINDINGS

An analysis of 740 cardiovascular studies reveals that women make up only 38.2% of participants on average. Regarding to trials testing the effectiveness of HF medications, women's involvement are as low as 23.1%. While current guidelines lack sex-specific treatment recommendations, emerging research suggests differential medication dosages could be beneficial. Studies indicate that women may achieve comparable outcomes with lower doses of certain medications (angiotensin-receptor blockers) compared to men, signaling potential for more tailored dosing approaches. We advocate that the next step in HF research should prioritize the importance of tailoring treatment for HF patients by taking into account the variations in drug absorption and distribution among women.

Dermatologic toxicities in epidermal growth factor receptor: a comprehensive pharmacovigilance study from 2013 to 2023

Epidermal growth factor receptor inhibitors (EGFRIs) induced cutaneous toxicity is a common adverse event (AE), although it is not as severe as major cancers, we still need to pay enough attention to them. Therefore, it is necessary to evaluate the diversity of EGFRI class drugs. The objective of this study was to conduct a scientific and systematic investigation into the correlation between EGFRI and cutaneous toxicities. The data accessed from the FDA adverse event reporting system database (FAERS) encompass a time frame spanning from January 2013 to March 2023. By utilizing reporting odds ratios (RORs), information components (ICs), proportional reporting ratios (PRRs), and chi-squared (χ2), the relationship between drugs and adverse reactions was evaluated through disproportionality analysis. Within the FAERS database, a total of 29,559 skin adverse events were recorded. A robust indication of the correlation between EGFRI and elderly patients (≥65 years) was identified. Among EGFRIs, erlotinib accounted for the largest proportion of skin adverse events (39.72%). Rash, dry skin, and pruritus ranked top among all preferred terms, and signals such as rash, skin lesions, and acneiform dermatitis were detected in every single drug. Clinicians should guide patients customize the treatment plan for each patient.

The Pharmacokinetics, Safety, and Tolerability of Rimegepant 75 mg Are Similar in Elderly and Nonelderly Adults: A Phase 1, Open-Label, Parallel-Group, Single-Dose Study

Rimegepant is a small-molecule calcitonin gene-related peptide receptor antagonist approved for the acute treatment of migraine ± aura and preventive treatment of migraine in adults. The pharmacokinetics of rimegepant in elderly and nonelderly subjects were evaluated. In an open-label Phase 1 study, 14 elderly (aged 65 years or older) and 14 nonelderly (aged 18 to less than 45 years) subjects each received a single oral dose of rimegepant 75 mg. Blood samples were collected before dosing and through 96 hours after dosing. The pharmacokinetic parameters of rimegepant after a single dose were similar in both age groups. Geometric least-squares mean ratios (elderly/nonelderly) of the natural log-transformed maximum observed plasma concentration and natural log-transformed area under the plasma concentration-time curve from time 0 extrapolated to infinity were 96.6 and 104.6, respectively. Eight (28.6%) subjects (4 elderly, 4 nonelderly) experienced 1 or more adverse events (AEs); all AEs were mild in intensity, and no serious AEs or AEs leading to discontinuation were reported. Following a single 75-mg dose of oral rimegepant, pharmacokinetic parameters were similar in elderly and nonelderly adults; no dose adjustment is warranted in elderly subjects.

[18F]DPA-714: Effect of co-medications, age, sex, BMI and TSPO polymorphism on the human plasma input function

PURPOSE

We aimed to assess the effect of concomitant medication, age, sex, body mass index and 18-kDa translocator protein (TSPO) binding affinity status on the metabolism and plasma pharmacokinetics of [18F]DPA-714 and their influence on the plasma input function in a large cohort of 201 subjects who underwent brain and whole-body PET imaging to investigate the role of neuroinflammation in neurological diseases.

METHODS

The non-metabolized fraction of [18F]DPA-714 was estimated in venous plasma of 138 patients and 63 healthy controls (HCs; including additional arterial sampling in 16 subjects) during the 90 min brain PET acquisition using a direct solid-phase extraction method. The mean fraction between 70 and 90 min post-injection ([18F]DPA-71470-90) and corresponding normalized plasma concentration (SUV70-90) were correlated with all factors using a multiple linear regression model. Differences between groups (arterial vs venous measurements; HCs vs patients; high- (HAB), mixed- (MAB) and low-affinity binders (LAB); subjects with vs without co-medications, females vs males were also assessed using the non-parametric Mann-Whitney or Kruskal-Wallis ANOVA tests. Finally, the impact of co-medications on the brain uptake of [18F]DPA-714 at equilibrium was investigated.

RESULTS

As no significant differences were observed between arterial and venous [18F]DPA-71470-90 and SUV70-90, venous plasma was used for correlations. [18F]DPA-71470-90 was not significantly different between patients and HCS (59.7 ± 12.3% vs 60.2 ± 12.9%) despite high interindividual variability. However, 47 subjects exhibiting a huge increase or decrease of [18F]DPA-71470-90 (up to 88% or down to 23%) and SUV70-90 values (2-threefold) were found to receive co-medications identified as inhibitors or inducers of CYP3A4, known to catalyse [18F]DPA-714 metabolism. Comparison between cortex-to-plasma ratios using individual input function (VTIND) or population-based input function derived from untreated HCs (VTPBIF) indicated that non-considering the individual metabolism rate led to a bias of about 30% in VT values. Multiple linear regression model analysis of subjects free of these co-medications suggested significant correlations between [18F]DPA-71470-90 and age, BMI and sex while TSPO polymorphism did not influence the metabolism of the radiotracer. [18F]DPA-714 metabolism fell with age and BMI and was significantly faster in females than in males. Whole-body PET/CT exhibited a high uptake of the tracer in TSPO-rich organs (heart wall, spleen, kidneys…) and those involved in metabolism and excretion pathways (liver, gallbladder) in HAB and MAB with a strong decrease in LAB (-89% and -85%) resulting in tracer accumulation in plasma (4.5 and 3.3-fold increase).

CONCLUSION

Any co-medication that inhibits or induces CYP3A4 as well as TSPO genetic status, age, BMI and sex mostly contribute to interindividual variations of the radiotracer metabolism and/or concentration that may affect the input function of [18F]DPA-714 and consequently its human brain and peripheral uptake.

TRIAL REGISTRATION

INFLAPARK, NCT02319382, registered December 18, 2014, retrospectively registered; IMABIO 3, NCT01775696, registered January 25, 2013, retrospectively registered; INFLASEP, NCT02305264, registered December 2, 2014, retrospectively registered; EPI-TEP, EudraCT 2017-003381-27, registered September 24, 2018.

Rationally Engineered CYP3A4 Fluorogenic Substrates for Functional Imaging Analysis and Drug-Drug Interaction Studies

Cytochrome P450 3A4 (CYP3A4) is a key xenobiotic-metabolizing enzyme-mediated drug metabolism and drug-drug interaction (DDI). Herein, an effective strategy was used to rationally construct a practical two-photon fluorogenic substrate for hCYP3A4. Following two-round structure-based substrate discovery and optimization, we have successfully constructed a hCYP3A4 fluorogenic substrate (F8) with desirable features, including high binding affinity, rapid response, excellent isoform specificity, and low cytotoxicity. Under physiological conditions, F8 is readily metabolized by hCYP3A4 to form a brightly fluorescent product (4-OH F8) that can be easily detected by various fluorescence devices. The practicality of F8 for real-time sensing and functional imaging of hCYP3A4 has been examined in tissue preparations, living cells, and organ slices. F8 also demonstrates good performance for high-throughput screening of hCYP3A4 inhibitors and assessing DDI potentials in vivo. Collectively, this study develops an advanced molecular tool for sensing CYP3A4 activities in biological systems, which strongly facilitates CYP3A4-associated fundamental and applied research studies.

Drug-induced liver injury: a comprehensive review

Drug-induced liver injury (DILI) remains a challenge in clinical practice and is still a diagnosis of exclusion. Although it has a low incidence amongst the general population, DILI accounts for most cases of acute liver failure with a fatality rate of up to 50%. While multiple mechanisms of DILI have been postulated, there is no clear causal relationship between drugs, risk factors and mechanisms of DILI. Current best practice relies on a combination of high clinical suspicion, thorough clinical history of risk factors and timeline, and extensive hepatological investigations as supported by the international Roussel Uclaf Causality Assessment Method criteria, the latter considered a key diagnostic algorithm for DILI. This review focuses on DILI classification, risk factors, clinical evaluation, future biomarkers and management, with the aim of facilitating physicians to correctly identify DILI early in presentation.

Effect of Dietary Intake on the Pharmacokinetics of the Multitargeted Receptor Tyrosine Kinase Inhibitor Famitinib: Results From a Phase 1 Study in Healthy Chinese Participants

Famitinib is a tyrosine kinase inhibitor under clinical investigation for the treatment of solid tumors. Here, a 3-period crossover trial investigated the effect of high-fat or low-fat food intake on the single-dose pharmacokinetic properties of oral famitinib. Twenty-four healthy Chinese participants were enrolled and received a single 25-mg dose of famitinib malate capsule following a high-fat or low-fat breakfast before dosing. Blood samples were collected before dosing (0 hour) to 192 hours after dosing, and famitinib concentrations in plasma were determined with validated liquid chromatography-tandem mass spectrometry. Compared with the fasting condition, the geometric mean ratios for low-fat/fasting were 98.6%, 107.7%, and 107.5% for maximum plasma concentration, area under the plasma concentration-time curve (AUC) over the dosing interval, and AUC from time 0 to infinity, respectively. Those for high-fat/fasting were 84.4%, 105.0%, and 105.1% for maximum plasma concentration, AUC over the dosing interval, and AUC from time 0 to infinity, respectively. There was no significant difference in adverse events between fasting and fed conditions, and no serious adverse events occurred during the trial. In conclusion, oral famitinib bioavailability is not affected by food intake, implying that patients with cancer do not need to consider dietary status when using famitinib. This is considered important for convenience and treatment compliance.

A Randomized, Open-Label, Phase I Clinical Study of Dalpiciclib With Different Specifications After Process Modification in Healthy Chinese Volunteers

The purpose of this study was to determine the pharmacokinetic characteristics and safety of dalpiciclib at 100-, 125-, and 150-mg doses after process modification in healthy Chinese volunteers. This single-center, randomized, open-label, three-dose, phase I clinical study was conducted in healthy Chinese adults. Thirty-six volunteers were randomized to three groups, including groups administered 100, 125, and 150 mg of dalpiciclib, and each group contained an equal number of males and females. A single oral dose of dalpiciclib was administered to each group, and plasma concentrations were measured by a validated liquid chromatography-tandem mass spectrometry method. The oral formulation of dalpiciclib was well absorbed, the plasma concentration reached the maximum concentration (C_max ) in 4-6 hours, and it was eliminated from plasma with a mean terminal half-life of 42.9-45.5 hours after 100-150 mg was administered. Dalpiciclib exhibited safety and favorable pharmacokinetic profiles, supporting further investigations in phase II studies. The plasma exposure of dalpiciclib was dose-dependent, with increasing doses in the range of 100-150 mg.

Sex Differences in Pharmacokinetics

Because women have been excluded from most clinical trials, assessment of sex differences in pharmacokinetics is available for a minority of currently prescribed drugs. In a 2020 analysis, substantial pharmacokinetic (PK) sex differences were established for 86 drugs: women given the same drug dose as men routinely generated higher blood concentrations and longer drug elimination times than men. 96% of drugs with higher PK values in women were associated with a higher incidence of adverse drug reactions (ADRs) in women than men; in the small number of instances when PKs of men exceeded those of women, this sex difference positively predicted male-biased ADRs in only 29% of cases. The absence of sex-stratified PK information for many medications raises the concern that sex differences in pharmacokinetics may be widespread and of clinical significance, contributing to sex-specific patterns of ADRs. Administering equal drug doses to women and men neglects sex differences in pharmacokinetics and body weight, risks overmedication of women, and contributes to female-biased ADRs. Evidence-based dosing adjustments are recommended to counteract this sex bias.

Sex and Age Influence on Association of CYP450 Polymorphism with Midazolam Levels in Critically Ill Children

Midazolam is a drug that is metabolized by cytochrome P450 (CYP450) enzymes, particularly CYP3A4 and CYP3A5. The present study aimed to determine the sex and age influence on association of CYP450 polymorphism with midazolam levels in critically ill children. Seventy-two DNA samples were genotyped by real-time PCR. Children ≤ five years of age who carry the rs776746 (T) allele in CYP3A5 gene were associated with lower plasma midazolam levels. The concentration median in patients was 0.0 ng/mL, while in patients with the normal (C) allele, it was 438.17 ng/mL (Q₂₅ 135.75-Q₇₅ 580.24), p = 0.005. The midazolam plasmatic concentration in female patients with the minor (T) allele was 0.0 ng/mL (Q₂₅0.00-Q₇₅204.3), while in patients with the normal (C) allele median it was 459.0 ng/mL (Q₂₅296.9-Q₇₅789.7), p = 0.002. Analysis of the dominant model for the rs2740574 variant in CYP3A4 revealed a median of 0.38 L/kg (Q₂₅0.02-Q₇₅1.5) for the volume of distribution parameter in female patients with the normal T allele, while female patients with the minor C allele showed a median of 18.1 L/kg (Q₂₅7.5-Q₇₅28.7) p = 0.02. Our results suggest an altered midazolam metabolism due to the presence the allelic rs2740574 variants of CYP3A4 and rs776746 of CYP3A5, and also the strong influence of age and sex.

The effect of rifampin on the pharmacokinetics of famitinib in healthy subjects

Background

Famitinib is an oral, small-molecule, multi-targeted tyrosine kinase inhibitor under clinical investigation for the treatment of solid tumors. As famitinib is metabolized mainly by cytochrome P450 3A4 (CYP3A4), the study was conducted to investigate the effect of potent CYP3A4 inducer rifampin on the pharmacokinetics of famitinb.

Methods

This single-center, single-arm and fixed-sequence drug–drug interaction study enrolled 21healthy Chinese male subjects. Subjects received a single oral dose of famitinib 25 mg on days 1 and 16 and repeated administration of oral rifampin 600 mg once daily on days 10–23. Blood samples were collected and plasma concentrations of famitinib were measured by validated liquid chromatography-tandem mass spectrometry (LC–MS/MS) method. Pharmacokinetic parameters were calculated using noncompartmental analysis and safety was assessed.

Results

In the presence of rifampin, the famitinib geometric mean maximum plasma concentration (Cmax) and area under the plasma concentration–time curve from time zero to infinity (AUC0–∞) decreased by 48% and 69%, respectively, and the mean elimination half-life was shortened from 33.9 to 18.2 h. The geometric mean ratio (GMR) of famitinib Cmax and AUC0–∞ and their 90% CI were 0.52 (0.50, 0.54) and 0.31 (0.29, 0.33). Single dose of famitinib 25 mg was well tolerated and eight subjects (38.1%) reported treatment emergent adverse events, which were all grade 1–2 in severity.

Conclusion

Co-administration of rifampin considerably reduces plasma concentration of famitinb due to CYP3A4 induction. Concomitant administration of famitinib and strong CYP3A4 inducers should be avoided, whereas when simultaneous use with inducers of CYP3A4, dose adjustment of famitinb is recommended.

Clinical trial registration number

NCT04494659 (July 31, 2020).

Efficacy and Safety of Daridorexant in Older and Younger Adults with Insomnia Disorder: A Secondary Analysis of a Randomised Placebo-Controlled Trial

Background and Objective

The dual orexin receptor antagonist daridorexant, studied in two phase III trials, dose-dependently improved objective and subjective sleep variables and daytime functioning in adults with insomnia. Because treatment of insomnia in older adults is challenging and has limited options, the purpose of the current analysis was to further analyse the phase III trial studying the higher doses of daridorexant, those that showed efficacy (daridorexant 50 mg, daridorexant 25 mg and placebo, nightly for 3 months), and compare the safety and efficacy of daridorexant in patients aged ≥ 65 (‘older adults’) to those aged < 65 years (‘younger adults’).

Methods

Analyses by age (≥ 65 years, n = 364; < 65 years, n = 566) were performed on data from the randomised, double-blind, placebo-controlled Trial 1 in adult patients with insomnia (NCT03545191). Efficacy endpoints included a change from baseline at month 1 and month 3 in polysomnography-measured wake after sleep onset (WASO) and latency to persistent sleep (LPS), self-reported total sleep time (sTST) and daytime functioning assessed using the validated Insomnia Daytime Symptoms and Impacts Questionnaire (IDSIQ). Safety endpoints included adverse events and the Visual Analog Scale for morning sleepiness.

Results

At baseline, mean [standard deviation] WASO was numerically greater (110 [39] vs 92 [38] min) in older than younger adults, while LPS was comparable (~ 65 min). Mean baseline IDSIQ total and all domain scores were numerically lower (i.e. better) in older adults. Daridorexant caused similar reductions in WASO and LPS, and similar increases in sTST, from baseline, in both age groups; improvements were numerically greater with daridorexant 50 mg than 25 mg. At month 3, daridorexant 50 mg, compared with placebo, decreased WASO by a least-squares mean of 19.6 (95% confidence interval 9.7, 29.5) in older patients versus 17.4 min (10.7, 24.0) in younger patients and decreased LPS by a least-squares mean of 14.9 (7.5, 22.3) in older patients versus 9.7 min (3.7, 15.7) in younger patients. Daridorexant 50 mg increased sTST from baseline to month 3 by a least-squares mean of 59.9 (49.6, 70.3) in older patients versus 57.1 min (48.9, 65.3) in younger patients. Daridorexant 50 mg progressively improved IDSIQ total and domain scores from week 1 onwards similarly in both groups; daridorexant 25 mg improved IDSIQ scores, but only in younger adults. In both age groups, in comparison with placebo, the overall incidence of adverse events was comparable, and there were fewer falls on daridorexant. Daridorexant improved Visual Analog Scale morning sleepiness in both groups; daridorexant 50 mg increased the mean (standard deviation) Visual Analog Scale morning sleepiness score by 15.9 (20.7) in older adults and by 14.9 (18.7) in younger adults from baseline to month 3. In older adults, there was one case of sleep paralysis, and no cases of narcolepsy, cataplexy, or complex sleep behaviour.

Conclusions

In older patients with insomnia, as in younger patients, the efficacy of daridorexant is maximal on night-time and daytime variables at the higher dose of 50 mg. Older patients particularly require this dose to improve daytime functioning. Older patients are not at an increased risk of adverse events or residual effects the next morning after night-time administration of daridorexant, even at 50 mg. The dose of daridorexant does not need to be decreased for older patients.

Clinical Trial Registration

ClinicalTrials.gov (NCT03545191) [first posted: 4 June, 4 2018], https://clinicaltrials.gov/ct2/show/NCT03545191.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40266-022-00977-4.

The burden of chronic insomnia (difficulty in falling/staying asleep or not getting enough sleep) increases with age yet treatment options in older patients are limited. In older patients, because of a risk of side effects, guidelines suggest caution when prescribing sleep medications and, for some drugs, recommend starting at a lower dose. Daridorexant was approved in 2022 for the treatment of insomnia in adults following positive results in two trials that showed daridorexant significantly improved night-time sleep and daytime functioning over 3 months of treatment in adults with insomnia. Approximately 40% of patients taking part in these trials were aged 65 years or older. This current analysis compared the safety and benefits of daridorexant in older adults (aged at least 65 years) and younger adults (aged less than 65 years) in the trial that administered the highest two doses of daridorexant, 25 and 50 mg. The results showed that the benefits of daridorexant were comparable in both age groups over 3 months; compared with placebo, daridorexant improved night-time sleep (reduced time awake during the night, reduced time to fall asleep and increased total sleep time) and daytime functioning—patients had less daytime sleepiness and a better mood and feeling of alertness. In older patients, the benefits, particularly for daytime functioning, were greatest at the higher 50-mg dose, without any increase in side effects. Both doses of daridorexant were equally well tolerated in the two age groups, indicating that treatment with daridorexant at 50 mg can be safely started in older patients.

Harnessing Clinical Trial and Real-World Data Towards an Understanding of Sex Effects on Drug Pharmacokinetics, Pharmacodynamics and Efficacy

Increasing clinical data on sex-related differences in drug efficacy and toxicity has highlighted the importance of understanding the impact of sex on drug pharmacokinetics and pharmacodynamics. Intrinsic differences between males and females, such as different CYP enzyme activity, drug transporter expression or levels of sex hormones can all contribute to different responses to medications. However, most studies do not include sex-specific investigations, leading to lack of sex-disaggregated pharmacokinetic and pharmacodynamic data. Based available literature, the potential influence of sex on exposure-response relationship has not been fully explored for many drugs used in clinical practice, though population-based pharmacokinetic/pharmacodynamic modelling is well-placed to explore this effect. The aim of this review is to highlight existing knowledge gaps regarding the effect of sex on clinical outcomes, thereby proposing future research direction for the drugs with significant sex differences. Based on evaluated drugs encompassing all therapeutic areas, 25 drugs demonstrated a clinically meaningful sex differences in drug exposure (characterised by ≥ 50% change in drug exposure) and this altered PK was correlated with differential response.

Potential drug-drug interaction between tolvaptan and warfarin in a geriatric patient with heart failure

Tolvaptan is a key drug for patients with heart failure. Here, we present a 92-year-old woman, whose PT-INR/dose increased from 1.74 to 3.30 after warfarin and tolvaptan co-administration, and resulted in a large cerebral infarction after warfarin dose down. Therefore, the interaction between these two drugs may be clinically significant.

CYP3A7, CYP3A4, and CYP3A5 genetic polymorphisms in recipients rather than donors influence tacrolimus concentrations in the early stages after liver transplantation

AIM

The purpose of this study was to investigate the effect of CYP3A7, CYP3A4, and CYP3A5 genetic polymorphisms in liver transplant recipients and donors on tacrolimus concentrations in the early stages after liver transplantation.

METHODS

One hundred and thirty-eight liver transplant recipients and matched donors were genotyped for CYP3A7 (rs10211 and rs2257401), CYP3A4 (rs4646437 and rs2242480), and CYP3A5*3 (rs776746) polymorphisms. The relationships between dose-adjusted trough concentrations (C₀/D) of tacrolimus and corresponding genotypes were investigated.

RESULTS

Recipient CYP3A polymorphisms were associated with tacrolimus concentrations. The CYP3A7 rs10211 AA carriers (186.2 vs 90.5, p < 0.001), CYP3A4 rs4646437 CC carriers (184.0 vs 88.8, p < 0.001), CYP3A4*1G rs2242480 CC carriers (189.8 vs 99.7, p < 0.001), and CYP3A5*3 rs776746 GG carriers (197.3 vs 86.0, p < 0.001) had an almost twofold increase in the tacrolimus C₀/D compared to that of the non-carriers. We further investigated the effect of the combination of recipient (intestinal) and donor (hepatic) genotypes on tacrolimus concentrations. Regardless of the genotype of the matched donor, CYP3A7 rs10211, CYP3A4*1G (rs2242480), and CYP3A5*3 (rs776746) polymorphisms of recipients could affect tacrolimus concentrations. For the CYP3A4 rs4646437 polymorphisms, when the donor carried CYP3A4 rs4646437 CC, the recipient CYP3A4 rs4646437 polymorphism was associated with the C₀/D of tacrolimus, and when the donor carried CYP3A4 rs4646437 CT/TT genotype, the recipient CYP3A4 rs4646437 polymorphism also affected on tacrolimus C₀/D, although the effect was not significant.

CONCLUSION

The large inter-individual variation in tacrolimus concentrations in the early stages after liver transplantation is influenced by genetic polymorphisms of CYP3A7, CYP3A4, and CYP3A5. Recipient (intestinal) CYP3A7, CYP3A4, and CYP3A5 polymorphisms seem to contribute more to such variation than donors. Therefore, the detection of CYP3A polymorphisms in recipients could help to predict the tacrolimus starting dose in the early stages after liver transplantation.

Therapeutic Drug Monitoring of Antibiotics in the Elderly: A Narrative Review

PURPOSE

Antibiotic dosing adaptation in elderly patients is frequently complicated by age-related changes affecting the processes of drug absorption, distribution, metabolism, and/or elimination. These events eventually result in treatment failure and/or development of drug-related toxicity. Therapeutic drug monitoring (TDM) can prevent suboptimal antibiotic exposure in adult patients regardless of age. However, little data are available concerning the specific role of TDM in the elderly.

METHODS

This review is based on a PubMed search of the literature published in the English language. The search involved TDM studies of antibiotics in the elderly performed between 1990 and 2021. Additional studies were identified from the reference lists of the retrieved articles. Studies dealing with population pharmacokinetic modeling were not considered.

RESULTS

Only a few studies, mainly retrospective and with observational design, have specifically dealt with appropriate antibiotic dosing in the elderly based on TDM. Nevertheless, some clinical situations in which the selection of optimal antibiotic dosing in the elderly was successfully guided by TDM were identified.

CONCLUSIONS

Elderly patients are at an increased risk of bacterial infections and inadequate drug dosing compared to younger patients. Therefore, the availability of TDM services can improve the appropriateness of antibiotic prescriptions in this population.

Tacrolimus Dose-Conversion Ratios Based on Switching of Formulations for Patients with Solid Organ Transplants

Background

Tacrolimus may be administered during hospitalization as an IV formulation or oral suspension. However, literature suggesting appropriate ratios for conversion from these formulations to capsules is limited.

Objective

To evaluate conversion ratios after a switch in formulation of tacrolimus for solid-organ transplant recipients.

Methods

This single-centre observational longitudinal study involved hospitalized patients who underwent a switch in formulation of tacrolimus according to 1 of 3 possible scenarios: IV to oral suspension, IV to capsule, or oral suspension to capsule. Data were collected from the earliest accessible electronic file (January 2009) to January 1, 2019. Conversion ratios were calculated for each of the 3 groups using data for blood concentrations and doses before and after the switch. The calculated ratios were then compared with recommended conversion ratios: 1:5 (i.e., 1 mg of IV tacrolimus is converted to 5 mg of oral tacrolimus, expressed as "5") for either of the switches involving an IV formulation and 1:1 (i.e., same amount, expressed as "1") for the switch from oral formulation to capsules.

Results

For the group who underwent switching from the IV formulation to oral suspension, the mean calculated conversion ratio was 3.04, which was significantly different from the recommended ratio of 5. For the group who underwent switching from the IV formulation to capsules, the calculated conversion ratio was 5.18, which was not significantly different from the recommended ratio of 5. For the group who underwent switching from oral suspension to capsules, the calculated conversion ratio was 1.17, which was not significantly different from the recommended ratio of 1.

Conclusion

In this small retrospective study of tacrolimus therapy, the calculated conversion ratio was significantly different from the recommended ratio for patients who were switched from IV administration to oral suspension, but not for those switched from IV administration or oral suspension to capsules. Therapeutic drug monitoring therefore appears indispensable, regardless of conversion ratios.

Sex-Biased Expression of Pharmacogenes across Human Tissues

Individual response to drugs is highly variable and largely influenced by genetic variants and gene-expression profiles. In addition, it has been shown that response to drugs is strongly sex-dependent, both in terms of efficacy and toxicity. To expand current knowledge on sex differences in the expression of genes relevant for drug response, we generated a catalogue of differentially expressed human transcripts encoded by 289 genes in 41 human tissues from 838 adult individuals of the Genotype-Tissue Expression project (GTEx, v8 release) and focused our analysis on relevant transcripts implicated in drug response. We detected significant sex-differentiated expression of 99 transcripts encoded by 59 genes in the tissues most relevant for human pharmacology (liver, lung, kidney, small intestine terminal ileum, skin not sun-exposed, and whole blood). Among them, as expected, we confirmed significant differences in the expression of transcripts encoded by the cytochromes in the liver, CYP2B6, CYP3A7, CYP3A5, and CYP1A1. Our systematic investigation on differences between male and female in the expression of drug response-related genes, reinforce the need to overcome the sex bias of clinical trials.

Influence of CYP2C19 Polymorphisms on the Pharmacokinetics of Omeprazole in Elderly Subjects

Omeprazole blocks the gastric H⁺ /K⁺  adenosine triphosphatase, thus inhibiting gastric acid secretion, and is metabolized by cytochrome P450 (CYP) 2C19. Due to the physiological changes in the elderly, there are different pharmacokinetic consequences compared to young people. The aim of this study was to evaluate the pharmacokinetic profiles of omeprazole in 15 elderly participants according to the CYP2C19 genotype. The concentration-time profiles of omeprazole and its metabolites, 5-hydroxy (5-OH) omeprazole and omeprazole sulfone, were similar between the CYP2C19 extensive metabolizer (EM) and intermediate metabolizer groups. In contrast, when comparing the EM group and CYP2C19 poor metabolizer (PM) group, the EM/PM geometric mean ratio (95% confidence interval) of area under the plasma concentration-time curve from time of dosing to the last measurable concentration was 0.52 (0.27-1.01) and that of the IM group was 0.71 (0.32-1.59), indicating that the exposure of omeprazole in the PM group was increased. The exposure of 5-OH omeprazole was significantly decreased in the PM group when compared to the EM group, with an EM/PM geometric mean ratio (95% confidence interval) of 2.20 (1.50-3.22). In conclusion, the tendency of drug exposure according to the CYP2C19 genotype in the elderly and young adults was similar in that the exposure level was highest in the PM group. However, when compared to young adults, the difference between the genotype groups was smaller in the elderly.

Long-term exposure to polypharmacy impairs cognitive functions in young adult female mice

The potential harmful effects of polypharmacy (concurrent use of 5 or more drugs) are difficult to investigate in an experimental design in humans. Moreover, there is a lack of knowledge on sex-specific differences on the outcomes of multiple-drug use. The present study aims to investigate the effects of an eight-week exposure to a regimen of five different medications (metoprolol, paracetamol, aspirin, simvastatin and citalopram) in young adult female mice. Polypharmacy-treated animals showed significant impairment in object recognition and fear associated contextual memory, together with a significant reduction of certain hippocampal proteins involved in pathways necessary for the consolidation of these types of memories, compared to animals with standard diet. The impairments in explorative behavior and spatial memory that we reported previously in young adult male mice administered the same polypharmacy regimen were not observed in females in the current study. Therefore, the same combination of medications induced different negative outcomes in young adult male and female mice, causing a significant deficit in non-spatial memory in female animals. Overall, this study strongly supports the importance of considering sex-specific differences in designing safer and targeted multiple-drug therapies.

Association of CYP3A5 polymorphisms and parathyroid hormone with blood level of tacrolimus in patients with end-stage renal disease

Because tacrolimus is predominantly metabolized by CYP3A, the blood concentration/dose (C/D) ratio is affected by CYP3A5 polymorphism. Parathyroid hormone (PTH) expression increases in secondary hyperparathyroidism, which is frequently associated with end‐stage renal disease. Recently, PTH has been shown to downregulate CYP3A expression at mRNA level. In this study, we examined the influence of CYP3A5 polymorphism on and association of serum intact‐PTH (iPTH) level with blood tacrolimus concentration in patients with end‐stage renal disease just before kidney transplantation. Forty‐eight patients who satisfied the selection criteria were analyzed. Subjects were classified into two phenotype subgroups: CYP3A5 expressor (CYP3A5*1/*1 and *1/*3; n = 15) and CYP3A5 nonexpressor (CYP3A5*3/*3; n = 33). The blood tacrolimus C/D (per body weight) ratio was significantly lower in CYP3A5 expressors than that in CYP3A5 nonexpressors. A significant positive correlation was found between tacrolimus C/D and iPTH concentrations (r = 0.305, p = 0.035), and the correlation coefficient was higher after excluding 20 patients co‐administered CYP3A inhibitor or inducer (r = 0.428, p = 0.023). A multiple logistic regression analysis by stepwise selection identified CYP3A5 polymorphism and serum iPTH level as significant factors associated with tacrolimus C/D. These results may suggest the importance of dose design considering not only the CYP3A5 phenotype but also serum iPTH level when using tacrolimus in patients who undergo renal transplantation.

Sex-related differences in the pharmacological treatment of heart failure

Heart failure (HF) represents a leading cause of morbidity and mortality. However, HF trials highlighted many differences between men and women with HF. Thus, women represent approximately a quarter of people with HF with reduced ejection fraction (HFrEF), while they account for over half of those with HF with preserved EF (HFpEF). There are also sex-related differences (SRDs) in the pharmacokinetics, pharmacodynamics and safety profile of some guideline-recommended drugs for the treatment of HF. As compared with men, women with HFrEF are less often treated with guideline-recommended HF drugs, experience more frequent and severe adverse reactions when these drugs are prescribed at the same doses in both sexes, and recent evidence suggests that women might need lower doses than men, bringing into question which are the optimal doses of HF drugs in women and men separately. However, information on SRDs in drug efficacy and safety in patients with HFrEF is very limited due to the underrepresentation of women and the lack of sex-specific evaluations of drug efficacy and safety in HF clinical trials. As a consequence, current clinical guidelines do not provide sex-specific recommendations, even when significant differences exist, at least, in drug safety. The aim of this article is to review the SRDs in the pharmacokinetics, efficacy and safety of guideline-recommended HF drugs and to identify emerging areas of research to improve our understanding of the SRDs, because a better understanding of these differences is the first step to achieve a personalized treatment of HF in women and men.

Antithrombotic therapy in the elderly and senile age: the consensus opinion of experts of the Russian Association of Gerontologists and Geriatricians and the National Society of Preventive Cardiology

В данном документе обсуждаются особенности АТТ у лиц пожилого и старческого возраста в различных клинических ситуациях.

Drug Induced Liver Injury in Geriatric Patients Detected by a Two-Hospital Prospective Pharmacovigilance Program: A Comprehensive Analysis Using the Roussel Uclaf Causality Assessment Method

Background/aim: A prospective evaluation of drug-induced liver injury (DILI) in two tertiary hospitals was conducted through a pharmacovigilance program from laboratory signals at hospital (PPLSH) to determine the principal characteristics of DILI in patients older than 65 years, a growing age group worldwide, which is underrepresented in the literature on DILI.

Methods: All DILI in patients older than 65 years detected by PPLSH in two hospitals were followed up for 8 years in the La Paz Hospital and 2 years in the Getafe Hospital. A descriptive analysis was conducted that determined the causality of DILI and suspected drugs, the incidence of DILI morbidities, DILI characteristics, laboratory patterns, evolution and outcomes.

Results: 458 DILI cases in 441 patients were identified, 31.0% resulting in hospitalisation and 69.0% developing during hospitalisation. The mean age was 76.61 years old (SD, 7.9), and 54.4% were women. The DILI incidence was 76.33/10,000 admissions (95%CI 60.78–95.13). Polypharmacy (taking >4 drugs) was present in 86.84% of patients, 39.68% of whom took >10 drugs. The hepatocellular phenotype was the most frequent type of DILI (53.29%), a higher proportion (65%) had a mild severity index, and, in 55.2% of the evaluated drugs the RUCAM indicated that the causal relationship was highly probable. The most frequently employed drugs were paracetamol (50-cases), amoxicillin-clavulanate (42-cases) and atorvastatin (37-cases). The incidence rate of in-hospital DILI per 10,000 DDDs was highest for piperacillin-tazobactam (66.96/10,000 DDDs). A higher risk of in-hospital DILI was associated with the therapeutic chemical group-J (antiinfectives for systemic use) (OR, 2.65; 95%CI 1.58–4.46) and group-N (central nervous system drugs) (OR, 2.33; 95%CI 1.26–4.31). The patients taking >4 medications presented higher maximum creatinine level (OR, 2.01; 95%CI 1.28–3.15), and the patients taking >10 medications had a higher use of group J drugs (OR, 2.08; 95%IC 1.31–3.32).

Conclusion: The incidence rate of DILI in the patients older than 65 years was higher than expected. DILI in elderly patients is mild, has a good outcome, has a hepatocellular pattern, develops during hospitalisation, and prolongs the hospital stay. Knowing the DILI incidence and explanatory factors will help improve the therapy of the elderly population.

Immunosuppression-related neurological disorders in kidney transplantation

A large number of neurological disorders can affect renal transplant recipients, potentially leading to disabling or life-threatening complications. Prevention, early diagnosis and appropriate management of these conditions are critical to avoid irreversible lesions. A pivotal role in the pathogenesis of common post-transplant neurological disorders is played by immunosuppressive therapy. The most frequently administered regimen consists of triple immunosuppression, which comprises a calcineurin inhibitor (CNI), a purine synthesis inhibitor and glucocorticoids. Some of these immunosuppressive drugs may lead to neurological signs and symptoms through direct neurotoxic effects, and all of them may be responsible for the development of tumors or opportunistic infections. In this review, after a brief summary of neurotoxic pathogenetic mechanisms encompassing recent advances in the field, we focus on the clinical presentation of more common and severe immunosuppression-related neurological complications, classifying them by characteristics of urgency and anatomic site. Our goal is to provide a general framework that addresses such clinical issues with a multidisciplinary approach, as these conditions require.

Body Mass Index as a Moderator of Treatment Response to Ketamine for Major Depressive Disorder

PURPOSE/BACKGROUND

Major depressive disorder (MDD) and obesity commonly co-occur. We sought to assess the impact of body mass index (BMI) on the acute antidepressant effects of ketamine in patients with treatment-resistant depression.

METHODS/PROCEDURES

Post hoc analyses were conducted from a multisite, randomized, double-blind, placebo-controlled trial designed to assess the rapid-onset effects of intravenous ketamine. Patients (n = 99) were randomized to a single dose administration of ketamine 0.1 mg/kg (n = 18), ketamine 0.2 mg/kg (n = 20), ketamine 0.5 mg/kg (n = 22), ketamine 1.0 mg/kg (n = 20), or active placebo, midazolam 0.045 mg/kg (n = 19). Patients were stratified for BMI. For patients randomized to ketamine (n = 80), BMI was assessed as a continuous variable and also categorically (obese, overweight, not obese/overweight [reference]). The primary outcome measure was the change on the 6-item Hamilton Depression Rating Scale 24 hours after treatment. Outcomes at day 3 were also assessed.

FINDINGS/RESULTS

The 6-item Hamilton Depression Rating Scale change scores at 24 hours were inversely associated with BMI (-0.28 ± 0.12, P = 0.02). With BMI operationalized categorically, both obese (-4.15 ± 1.41, P = 0.004) and overweight (-1.99 ± 1.14, P = 0.08) categories were inversely related to the 6-item Hamilton Depression Rating Scale change score at 24 hours, statistically significant for the obese category, as compared with the reference group. Similar but weaker findings were observed at 72 hours after infusion.

IMPLICATIONS/CONCLUSIONS

Higher BMI and obesity were associated with a more robust acute antidepressant response to ketamine. This may have clinical relevance for a great number of patients who have both MDD and obesity.

CLINICAL TRIAL REGISTRATION

NCT01920555.

Cytochrome P450 expression, induction and activity in human induced pluripotent stem cell-derived intestinal organoids and comparison with primary human intestinal epithelial cells and Caco-2 cells

Human intestinal organoids (HIOs) are a promising in vitro model consisting of different intestinal cell types with a 3D microarchitecture resembling native tissue. In the current study, we aimed to assess the expression of the most common intestinal CYP enzymes in a human induced pluripotent stem cell (hiPSC)-derived HIO model, and the suitability of that model to study chemical-induced changes in CYP expression and activity. We compared this model with the commonly used human colonic adenocarcinoma cell line Caco-2 and with a human primary intestinal epithelial cell (IEC)-based model, closely resembling in vivo tissue. We optimized an existing protocol to differentiate hiPSCs into HIOs and demonstrated that obtained HIOs contain a polarized epithelium with tight junctions consisting of enterocytes, goblet cells, enteroendocrine cells and Paneth cells. We extensively characterized the gene expression of CYPs and activity of CYP3A4/5, indicating relatively high gene expression levels of the most important intestinal CYP enzymes in HIOs compared to the other models. Furthermore, we showed that CYP1A1 and CYP1B1 were induced by β-naphtoflavone in all three models, whereas CYP3A4 was induced by phenobarbital and rifampicin in HIOs, in the IEC-based model (although not statistically significant), but not in Caco-2 cells. Interestingly, CYP2B6 expression was not induced in any of the models by the well-known liver CYP2B6 inducer phenobarbital. In conclusion, our study indicates that hiPSC-based HIOs are a useful in vitro intestinal model to study biotransformation of chemicals in the intestine.

Incidence and prognostic factors of clinically meaningful toxicities of kinase inhibitors in older patients with cancer: The PreToxE study

Most of the safety data of tyrosine and serine/threonine kinase inhibitors (TKIs) approved for cancer treatment are extrapolated from larger trials in which older patients generally accounted for a small fraction of the participants. The Predicting Severe Toxicity of Targeted Therapies in Elderly Patients With Cancer study (PreToxE)PreToxE study aims to describe the incidence and prognostic factors of clinically meaningful toxicities of TKI in patients with cancer aged over 70 years. The primary endpoint was incidence of severe toxicity, defined as treatment-related death, persistent or significant disability/incapacity, hospitalization or the discontinuation of TKI treatment for more than three weeks. Our results indicate that despite frequent upfront dose reduction, clinically meaningful toxicities occurred in approximately 40% of older patients treated with TKIs. The use of at least three concomitant medications is an independent predictor of clinically meaningful toxicities.

Slow Accumulation and Elimination of Diazepam and Its Active Metabolite With Extended Treatment in the Elderly

Age-related changes in disposition of diazepam and its principal active metabolite, desmethyldiazepam (DMDZ), during and after extended dosage with diazepam were studied in healthy volunteers. Eight elderly subjects (ages 61-78 years) and 7 young subjects (21-33 years) received 2.5 mg of diazepam twice daily for 15 days. Predose (trough) concentrations of diazepam and DMDZ were measured during the 15 days of dosing, and in the postdosage washout period. Kinetic properties were determined by nonlinear regression using a sequential drug-to-metabolite pharmacokinetic model. Steady-state plasma concentrations of diazepam and DMDZ were 30% to 35% higher in elderly subjects compared to young volunteers, and steady-state clearances correspondingly lower, though differences did not reach significance. Large and significant differences were found between young and elderly groups in mean half-life of diazepam (31 vs 86 hours; P < .005) and DMDZ (40 vs 80 hours; P < .02). Half-life values from the multiple-dose study were closely correlated with values from previous single-dose studies of diazepam (R² = 0.85) and DMDZ (R² = 0.94) in the same subjects. With extended dosing of diazepam in the elderly, slow accumulation and delayed washout of diazepam and DMDZ is probable. After discontinuation, withdrawal or rebound effects are reduced in likelihood, but delayed recovery from sedative effects is possible due to slow elimination of active compounds. Safe treatment of elderly patients with diazepam is supported by understanding of age-related changes in pharmacologic and pharmacokinetic properties.

Orally Administered Koumine Persists Longer in the Plasma of Aged Rats Than That of Adult Rats as Assessed by Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

Aging leads to changes in nearly all pharmacokinetic phases. Koumine (KM), an alkaloid derived from Gelsemium elegans Benth., is effective against age-associated chronic diseases, but its dose proportionality following oral administration in aged individuals remains unknown. Herein, we established and validated a simple method that requires low sample volumes to determine KM concentration in rats using ultra-performance liquid chromatography-tandem mass spectrometry. The maximum plasma concentration (C_max) of 7 mg·kg⁻¹ KM was ~12-fold and ~24-fold higher than that of 0.28 mg·kg⁻¹ KM in adult and aged rats, respectively (P < 0.01). Time to reach C_max (T_max) for 7 mg·kg⁻¹ KM was 4-fold longer in aged rats (P < 0.05). The area under the curve (AUC) of 7 mg·kg⁻¹ KM was >17-fold and >43-fold higher than those of 0.28 mg·kg⁻¹ KM in adult and aged rats, respectively (P < 0.01). The half-life (t_1/2) of 7 mg·kg⁻¹ KM was over 4-fold longer than that of 0.28 mg·kg⁻¹ KM in adult rats (P < 0.01). The t_1/2 of 1.4 and 7 mg·kg⁻¹ KM were 1.5~2-fold longer, than that of 0.28 mg·kg⁻¹ KM in aged rats (P < 0.05). The clearance rate of 7 mg·kg⁻¹ KM was significantly lower in aged than in adult rats (P < 0.05). For 7.0 mg·kg⁻¹ KM, the C_max in aged rats was higher than in adult rats during the T_max period (P < 0.05). In aged rats, the AUC for KM was >2.5-fold higher (P < 0.05) and the t_1/2 was >60% longer than in adult rats (P < 0.05). These results help interpret the pharmacokinetics of KM in aging-associated diseases.

Sex differences in pharmacokinetics predict adverse drug reactions in women

BACKGROUND

Women experience adverse drug reactions, ADRs, nearly twice as often as men, yet the role of sex as a biological factor in the generation of ADRs is poorly understood. Most drugs currently in use were approved based on clinical trials conducted on men, so women may be overmedicated. We determined whether sex differences in drug pharmacokinetics, PKs, predict sex differences in ADRs.

METHODS

Searches of the ISI Web of Science and PubMed databases were conducted with combinations of the terms: drugs, sex or gender, pharmacokinetics, pharmacodynamics, drug safety, drug dose, and adverse drug reaction, which yielded over 5000 articles with considerable overlap. We obtained information from each relevant article on significant sex differences in PK measures, predominantly area under the curve, peak/maximum concentrations, and clearance/elimination rates. ADRs were identified from every relevant article and recorded categorically as female-biased, male-biased, or not sex-biased.

RESULTS

For most of the FDA-approved drugs examined, elevated blood concentrations and longer elimination times were manifested by women, and these PKs were strongly linked to sex differences in ADRs. Of the 86 drugs evaluated, 76 had higher PK values in women; for 59 drugs with clinically identifiable ADRs, sex-biased PKs predicted the direction of sex-biased ADRs in 88% of cases. Ninety-six percent of drugs with female-biased PK values were associated with a higher incidence of ADRs in women than men, but only 29% of male-biased PKs predicted male-biased ADRs. Accessible PK information is available for only a small fraction of all drugs CONCLUSIONS: Sex differences in pharmacokinetics strongly predict sex-specific ADRs for women but not men. This sex difference was not explained by sex differences in body weight. The absence of sex-stratified PK information in public records for hundreds of drugs raises the concern that sex differences in PK values are widespread and of clinical significance. The common practice of prescribing equal drug doses to women and men neglects sex differences in pharmacokinetics and dimorphisms in body weight, risks overmedication of women, and contributes to female-biased adverse drug reactions. We recommend evidence-based dose reductions for women to counteract this sex bias.

The effects of aripiprazole and olanzapine on pupillary light reflex and its relationship with pharmacogenetics in a randomized multiple-dose trial

Aims

Pupillography is a noninvasive and cost‐effective method to determine autonomic nerve activity. Genetic variants in cytochrome P450 (CYP), dopamine receptor (DRD2, DRD3), serotonin receptor (HTR2A, HTR2C) and ATP‐binding cassette subfamily B (ABCB1) genes, among others, were previously associated with the pharmacokinetics and pharmacodynamics of antipsychotic drugs. Our aim was to evaluate the effects of aripiprazole and olanzapine on pupillary light reflex related to pharmacogenetics.

Methods

Twenty‐four healthy volunteers receiving 5 oral doses of 10 mg aripiprazole and 5 mg olanzapine tablets were genotyped for 46 polymorphisms by quantitative polymerase chain reaction. Pupil examination was performed by automated pupillometry. Aripiprazole, dehydro‐aripiprazole and olanzapine plasma concentrations were measured by high‐performance liquid chromatography–tandem mass spectrometry.

Results

Aripiprazole affected pupil contraction: it caused dilatation after the administration of the first dose, then caused constriction after each dosing. It induced changes in all pupillometric parameters (P < .05). Olanzapine only altered minimum pupil size (P = .046). Polymorphisms in CYP3A, HTR2A, UGT1A1, DRD2 and ABCB1 affected pupil size, the time of onset of constriction, pupil recovery and constriction velocity. Aripiprazole, dehydro‐aripiprazole and olanzapine pharmacokinetics were significantly affected by polymorphisms in CYP2D6, CYP3A, CYP1A2, ABCB1 and UGT1A1 genes.

Conclusions

In conclusion, aripiprazole and its main metabolite, dehydro‐aripiprazole altered pupil contraction, but olanzapine did not have such an effect. Many polymorphisms may influence pupillometric parameters and several polymorphisms had an effect on aripiprazole, dehydro‐aripiprazole and olanzapine pharmacokinetics. Pupillography could be a useful tool for the determination of autonomic nerve activity during antipsychotic treatment.

Influence of POR*28 Polymorphisms on CYP3A5*3-Associated Variations in Tacrolimus Blood Levels at an Early Stage after Liver Transplantation

It is well known that the CYP3A5*3 polymorphism is an important marker that correlates with the tacrolimus dose requirement after organ transplantation. Recently, it has been revealed that the POR*28 polymorphism affects the pharmacokinetics of tacrolimus in renal transplant patients. In this study, we examined whether POR*28 as well as CYP3A5*3 polymorphism in Japanese recipients and donors would be another biomarker for the variation of tacrolimus blood levels in the recipients during the first month after living-donor liver transplantation. We enrolled 65 patients treated with tacrolimus, who underwent liver transplantation between July 2016 and January 2019. Genomic DNA was extracted from whole-blood samples, and genotyping was performed to examine the presence of CYP3A5*3 and POR*28 polymorphisms in the recipients and donors. The CYP3A5*3/*3 genotype (defective CYP3A5) of the recipient (standard partial regression coefficient [median C/D ratio of CYP3A5 expressor vs. CYP3A5 non-expressor, p value]: Pod 1–7, β= −0.389 [1.76 vs. 2.73, p < 0.001]; Pod 8–14, β = −0.345 [2.03 vs. 2.83, p < 0.001]; Pod 15–21, β= −0.417 [1.75 vs. 2.94, p < 0.001]; Pod 22–28, β = −0.627 [1.55 vs. 2.90, p < 0.001]) rather than donor (Pod 1–7, β = n/a [1.88 vs. 2.76]; Pod 8–14, β = n/a [1.99 vs. 2.93]; Pod 15–21, β = −0.175 [1.91 vs. 2.94, p = 0.004]; Pod 22–28, β = n/a [1.61 vs. 2.67]) significantly contributed to the increase in the concentration/dose (C/D) ratio of tacrolimus for at least one month after surgery. We found that the tacrolimus C/D ratio significantly decreased from the third week after transplantation when the recipient carried both CYP3A5*1 (functional CYP3A5) and POR*28 (n = 19 [29.2%], median C/D ratio [inter quartile range] = 1.58 [1.39–2.17]), compared with that in the recipients carrying CYP3A5*1 and POR*1/*1 (n = 8 [12.3%], median C/D ratio [inter quartile range] = 2.23 [2.05–3.06]) (p < 0.001). In conclusion, to our knowledge, this is the first report suggesting that the POR*28 polymorphism is another biomarker for the tacrolimus oral dosage after liver transplantation in patients carrying CYP3A5*1 rather than CYP3A5*3/*3.

Clinical pharmacology of the dual orexin receptor antagonist ACT-541468 in elderly subjects: Exploration of pharmacokinetics, pharmacodynamics and tolerability following single-dose morning and repeated-dose evening administration

BACKGROUND

The dual orexin receptor antagonist ACT-541468 showed sedative pharmacodynamic effects during initial clinical testing in adult subjects. The present study explored pharmacokinetics, pharmacodynamics and tolerability in healthy elderly subjects.

METHODS

Double-blind, placebo-controlled, randomised, single-ascending dose study in 24 male/female elderly (65-80 years, 5, 15 and 25 mg in the morning, 6/2 active/placebo per group). Additionally, 10 subjects (8/2 active/placebo) received 25 mg for 7 days in the evening. Pharmacokinetics, pharmacodynamics (saccadic peak velocity, adaptive tracking, body sway, visual analogue scales according to Bowdle and Bond and Lader, Karolinska Sleepiness Scale) and tolerability were assessed. In particular, pharmacodynamics results are to be interpreted exploratorily.

RESULTS

Absorption was quick with a median time to maximum concentration of ∼ 1.0 h. The mean elimination half-life was 8.5-9.8 h, the area under the curve and the maximum plasma concentration increased proportionally with dose. Following repeated evening administration of 25 mg, minimal accumulation was observed. There were no pharmacodynamic effects at 5 mg. At 15 mg, saccadic peak velocity (degree/s; SD) was reduced (69; 38), while other variables showed no effects. At 25 mg, effects on all objective pharmacodynamic parameters were observed. At 8-12 h post-dose, there were no differences to placebo and no next-day effects on pharmacodynamic variables after evening administration. Elderly subjects reported fewer adverse events compared to adults in previous studies.

CONCLUSION

ACT-541468 in elderly subjects was well tolerated and pharmacokinetics and pharmacodynamics are compatible with a drug for the treatment of insomnia. Clinicaltrials.gov: NCT02571855.

Multicenter-Based Population Pharmacokinetic Analysis of Ciclosporin in Hematopoietic Stem Cell Transplantation Patients

PURPOSE

To explore the contribution of physiological characteristics to variability in ciclosporin pharmacokinetics in hematopoietic stem cell transplantation patients.

METHODS

Clinical data from 563 patients were collected from centers in three regions. Ciclosporin concentrations were measured using immunoassays. The patients' demographics, hematological and biological indicators, coadministered drugs, region, and disease diagnosis were recorded from medical records. Data analysis was performed using NONMEM based on a one-compartment model to describe the pharmacokinetics of ciclosporin. The reliability and stability of the final model were evaluated using bootstrap resampling, goodness-of-fit plots, and prediction-corrected visual predictive checks.

RESULTS

The population estimate of the clearance (CL) was 30.4 L/h, the volume of distribution (V) was 874.0 L and the bioavailability (F) was 81.1%. The between-subject variability in these parameters was 26.3, 68.0, and 110.8%, respectively. Coadministration of fluconazole, itraconazole, or voriconazole decreased CL by 17.6%, 28.4%, and 29.2%, respectively. Females' CL increased by approximately 12.0%. In addition, CL and V decreased with hematocrit, total protein, and uric acid increase, and CL also decreased with age and aspartate aminotransferase increase. However, CL increased with creatinine clearance increase.

CONCLUSIONS

A multicenter-based population pharmacokinetic model of ciclosporin was established. The pharmacokinetics of ciclosporin exhibited discrepancies among different regions.

Investigations on hepatic and intestinal drug-metabolizing cytochrome P450 enzymes in wild boar compared to domestic swine

Drug-metabolizing cytochrome P450 (CYP) enzymes are especially important in wild animals as they are directly exposed to environmental pollutants and bioactive molecules of plants. Our main goal was to monitor the activity of certain CYP enzymes in wild boar compared to domestic swine, and to assess various modulatory factors of xenobiotic biotransformation in wild boar. Liver and intestinal mucosa (duodenum, jejunum, ileum, caecum) samples were collected from 49 hunted free-range wild boars and 15 wild boar fetuses; domestic pig samples (n = 40) were gained from a slaughter house. Specific activity of CYP1A2, CYP2C9, and CYP3A4 enzymes was assessed by luminometric assays. The activity of hepatic CYP1A2 and CYP3A4 enzymes was significantly higher in wild boars than in domestic pigs, while CYP2C9-mediated hepatic metabolism was significantly less intense in wild boars than in pigs. Certain modulatory factors (sex, sexual maturation, and season) were also confirmed in wild boars. The activity of all investigated intestinal CYP enzymes remained under detection level in each gut section in both species. Hepatic CYP2C9 and CYP3A4 enzymes were measurable in wild boar fetuses, but their activity was remarkably lower than in adults. The described interspecies differences might be explained with the altered exposure of wild and domesticated animals to specific CYP modulators. As CYP enzymes in wild boars can be highly influenced by environmental pollutants, following further studies, they may serve as ecotoxicological markers of agricultural or industrial toxicants. Investigating CYP-related drug metabolism in wildlife species can clarify some toxicokinetic interactions, thus having huge importance in the production of safe game meat.