Drug Exposure Research Articles

Steady-State Drug Exposure of Repeated IV Bolus Administration for a One Compartment Pharmacokinetic Model with Sigmoidal Hill Elimination.

Drugs exhibiting nonlinear pharmacokinetics hold significant importance in drug research and development. However, evaluating drug exposure accurately is challenging with the current formulae established for linear pharmacokinetics. This article aims to investigate the steady-state drug exposure for a one-compartment pharmacokinetic (PK) model with sigmoidal Hill elimination, focusing on three key topics: the comparison between steady-state drug exposure of repeated intravenous (IV) bolus ( ) and total drug exposure after a single IV bolus ( ); the evolution of steady-state drug concentration with varying dosing frequencies; and the control of drug pharmacokinetics in multiple-dose therapeutic scenarios. For the first topic, we established conditions for the existence of , derived an explicit formula for its calculation, and compared it with . For the second, we identified the trending properties of steady-state average and trough concentrations concerning dosing frequency. For the third, we developed formulae to compute dose and dosing time for both regular and irregular dosing scenarios. As an example, our findings were applied to a real drug model of progesterone used in lactating dairy cows. In conclusion, these results provide a theoretical foundation for designing rational dosage regimens and conducting therapeutic trials.

Collateral sensitivity counteracts the evolution of antifungal drug resistance in Candida auris.

Antifungal drug resistance represents a serious global health threat, necessitating new treatment strategies. Here we investigated collateral sensitivity (CS), in which resistance to one drug increases sensitivity to another, and cross-resistance (XR), in which one drug resistance mechanism reduces susceptibility to multiple drugs, since CS and XR dynamics can guide treatment design to impede resistance development, but have not been systematically explored in pathogenic fungi. We used experimental evolution and mathematical modelling of Candida auris population dynamics during cyclic and combined drug exposures and found that especially CS-based drug cycling can effectively prevent the emergence of drug resistance. In addition, we found that a CS-based treatment switch can actively select against or eradicate resistant sub-populations, highlighting the potential to consider CS in therapeutic decision-making upon resistance detection. Furthermore, we show that some CS trends are robust among different strains and resistance mechanisms. Overall, these findings provide a promising direction for improved antifungal treatment approaches.

Uncovering the Impact of COVID-19 Mediated Bidirectional Dysregulation of CYP3A4 on Systemic and Pulmonary Drug Concentrations Using Physiologically Based Pharmacokinetic Modeling.

Several clinical studies have shown that COVID-19 increases the systemic concentration of drugs in hospitalized COVID-19 patients. However, it is unclear how COVID-19-mediated bidirectional dysregulation of hepatic and pulmonary CYP3A4 impacts drug concentrations, especially in the lung tissue which is most affected by the disease. Herein, PBPK modeling was used to demonstrate the differences in systemic and pulmonary concentrations of four respiratory infectious disease drugs when CYP3A4 is concurrently downregulated in the liver and upregulated in the lung based on existing clinical data on COVID-19 - CYP3A4 interactions at varying severity levels including outpatients, non-ICU, and ICU patients. The study showed that hepatic metabolism is the primary determinant of both systemic and pulmonary drug concentrations despite the concurrent bidirectional dysregulation of liver and lung CYP3A4. ICU patients had the most systemic and pulmonary drug exposure with a percentage increase in AUCplasma of approximately 44%, 56%, 114%, and 196% for clarithromycin, nirmatrelvir, dexamethasone, and itraconazole, respectively, relative to the healthy group. Within the ICU cohort, clarithromycin exhibited its highest exposure in lung tissue mass with a fold change of 1189, while nirmatrelvir and dexamethasone showed their highest exposure in the plasma compartment, with fold changes of about 126 and 5, respectively, compared to the maximum therapeutic concentrations for their target pathogens. Itraconazole was significantly under-exposed in the lung fluid compartment potentially explaining its limited efficacy for the treatment of COVID-19. These findings underscore the importance of optimizing dosing regimens in at risk ICU patients to enhance both efficacy and safety profiles. Significance Statement This study investigated whether COVID-19-mediated concurrent hepatic downregulation and pulmonary upregulation of CYP3A4 leads to differences in the systemic and pulmonary concentrations of four respiratory medicines. The study demonstrated that intercompartmental differences in drug concentrations were driven by only hepatic CYP3A4 expression. This work suggests that ICU patients with significant COVID-19 - CYP3A4 interactions may be at risk of clinically relevant COVID-19-drug interactions, highlighting the need for optimizing dosing regimens in this patient group to improve safety and efficacy.

Idiopathic pulmonary arterial hypertension, associated with connective tissue disease and comorbidities: prognostic differences? Results the Spanish Registry of pulmonary hypertension (REHAP Registry)

Abstract Introduction Idiopathic pulmonary arterial hypertension (iPAH) and associated with connective tissue disease (PAH-SSc) are the most frequent groups of pulmonary arterial hypertension (PAH) but their long-term survival is usually unequal. Comorbidities, increasing in frequency in these patients, show prognostic influences but it is not known whether these differ in both groups of patients. Methods We collected patients diagnosed with iPAH, heritable, associated with drug or toxine exposure and PAH-SSc between 2014 and 2023 from the Spanish Registry of Pulmonary Hypertension. Patients are classifies into iPAH and PAH-SSc. We analyzed baseline characteristics and the distribution of the different comorbidities in the two groups. Survival analyses estimated by Kaplan-Meier analysis using the log-rank test were done according to PAH etiology and comorbidities and Cox proportional hazard analyses were performed to determine the effects of baseline characteristics on survival. Results Seven hundred and fifty-seven patients were selected for this study. The characteristics of the patients are shown in Table 1. Patients with PAH-SSc compared to iPAH were older (62 vs 56 years), more female (81.8% vs 62.4%), had a more favorable hemodynamic profile, TAPSE/sPAP ratio and lower NT-proBNP levels. No differences were found in functional class or 6MWT. We found a higher proportion of patients in a low and intermediate risk profile, according to ESC, in patients with PAH-SSC as opposed to PAHi (46.8/50.9% vs. 29.3/64.5%; p<0.001). Regarding comorbidities, history of smoking (27.1 vs 54%; p<0-001), obesity (17.1 vs 20.7%; p<0.001) and diabetes (9.4 vs 22.1%; p<0.001) are less frequent in PAH-SSc than in iPAH. There are no differences in the rest of the comorbidities studied in the two groups of patients. In a survival analysis, we found no differences between patients with iPAH and PAH-SSc at 7-year follow-up. Patients with ≥ 3 comorbidities had statistically significantly higher mortality (p<0.001) compared to those with 0 or 1-2 comorbidities in both etiologies. There were no differences between 0 and 1-2 comorbidities. (Figure 1). Variables associated with mortality were male sex (HR 1.9, 95% CI 1,28 – 2.8), age (HR 1.04, 95% CI 1.02 – 1.06), the intermediate risk profile (HR 2.64, 95% CI 1.62 – 4.32) and high risk profile (HR 9.97, 95% CI 4.36 – 18.47), but not etiology. The presence of connective tissue diseases, were not associated with increased mortality. Conclusions Patients with PAH-SSc show lower comorbidities, better hemodynamic profile, RV-PA coupling and risk profile than those with iPAH. Comorbidity has a great relevance in survival but without differences according to etiology. The presence of male sex, age, the intermediate and high risk profile is associated with worse survival, but not the connective tissue diseases.

The importance of comorbidities in idiopathic and associated with connective tissue disease pulmonary arterial hypertension: from the Spanish Registry of Pulmonary Hypertension (REHAP Registry)

Abstract Introduction Comorbidities play a major role in the prognosis of patients with pulmonary arterial hypertension (PAH). These comorbidities are present in more than 80% of patients diagnosed in the last years with idiopathic PAH (iPAH) and their presence is associated with increased morbidity and mortality although its influence on PAH associated with connective tissue disease (PAH-SSc) is unknown. We studied the impact of comorbidities on iPAH and PAH-SSc in the Spanish population. Methods We collected patients diagnosed with iPAH, heritable, associated with drug or toxine exposure and PAH-SSc between 2014 and 2023 from the Spanish Registry of Pulmonary Hypertension. Patients are classified into: no comorbidities, 1-2 comorbidities and ≥3 comorbidities. We analyzed the impact of comorbidities in baseline characteristics, exercise capacity and hemodynamic profile, as well as in the risk profile and initial treatment. Survival analyses estimated by Kaplan-Meier analysis using the log-rank test and Cox proportional hazard analyses were performed to determine the effects of baseline characteristics on survival. Results 757 patients were selected for this study. The characteristics of the patients are shown in Table 1. As the number of comorbidities increases (0/1-2/≥3) we found higher age (49/59/67 years; p<0.001), higher percentage of male sex (12.9/29.9/43.4%; p<0.001) and higher FC III at diagnosis (42.7/46.9/59.6%; p=0.013). We observed a shorter distance in 6MWD, higher NT-proBNP levels, lower DLCO and a less unfavorable hemodynamic profile (PAPm, PAWP, CI and PVR). The most frequent comorbidities were a history of smoking (46.4%), followed by arterial hypertension (41.5%), obesity (24.6%) and chronic kidney disease (19.2%). Diabetes mellitus, although less frequent, reached more than 55% in patients with ≥3 comorbidities (p<0.001). The presence of ≥ 3 comorbidities was more frequent in iPAH than PAH-SSc (p<0,001). Intermediate risk profile was the most common (58.4%) and this reached 68.7% in those with ≥3 comorbidities due to a lower number of patients in a low-risk profile (p<0.001). A statistically significant lower survival (p<0.001) was observed in patients with ≥ 3 comorbidities; however, we found no differences between 0 and 1-2 comorbidities at 7-year follow-up (Figure 1). Variables associated with mortality were male sex (HR 1.88, 95% CI 1,26 – 2.8), age (HR 1.04, 95% CI 1.02 – 1.06) and the presence of ≥3 comorbidities (HR 1.49, 95% CI 0.98 – 2.27), not the presence of connective tissue diseases, which were not associated with increased mortality in our study. Conclusions The presence of comorbidities in iPAH and PAH-SSc is very frequent in the Spanish population. They are associated with a worse clinical profile, risk profile, lower use of oral double theraphy and prostacyclins. The presence of ≥3 comorbidities is associated with worse survival, not the presence of 1-2 comorbidities or connective tissue disease.

Impact of differences in body mass index, body surface area and lean body mass on clinical outcomes in patients with atrial fibrillation receiving edoxaban: 4-year follow-up data from ETNA-AF-Europe

Abstract Background In patients with atrial fibrillation (AF) treated with non-vitamin K antagonist oral anticoagulants, extremes in body weight and its anthropometric correlates (body mass index [BMI], body surface area [BSA] and lean body mass [LBM]) may affect drug exposure and the occurrence of thromboembolic or haemorrhagic events. Purpose To investigate the association of BMI, BSA and LBM with clinical outcomes according to sex in edoxaban-treated patients with AF using 4-year data from ETNA-AF-Europe (NCT02944019). Methods The prospective, observational ETNA-AF-Europe study followed patients with AF receiving edoxaban for up to 4 years. In this subanalysis, patients were categorised into tertiles (low, middle, and high) for BMI, BSA and LBM and stratified by sex. Baseline characteristics and rates of any thromboembolic and haemorrhagic events per 100 patient-years ([%]/100PY) are reported using 4-year follow-up data. Results Of 13,164 patients, 7461 were men and 5703 were women. Table 1 shows the ranges of BMI, BSA and LBM, defining the low, middle, and high tertiles, and their corresponding baseline characteristics. Irrespective of sex, patients in the low tertile for BMI, BSA and LBM were older and more likely to have renal impairment, history of stroke, and to receive appropriate edoxaban 30mg or non-appropriate edoxaban 60mg. Patients in the high tertile were more likely to have diabetes and hypertension. Overall, the rate (%)/100PY of any thromboembolic event was slightly lower (0.8 vs 1.1%), whereas the corresponding rate of any haemorrhagic event was slightly higher (1.9 vs 1.7%) in men vs women (Figure 1). For BMI, BSA and LBM in men, rates (%)/100PY of any thromboembolic event were similar among tertiles (low, middle, high; BMI, 0.9, 0.8 and 0.8%; BSA, 0.9, 0.8 and 0.8%; LBM, 0.9, 0.7 and 0.9%). For BMI, rates (%)/100PY of any haemorrhagic event were similar among tertiles in men (BMI, 1.9, 1.8 and 2.0%), but highest in the low tertile for BSA and LBM (BSA, 2.4, 1.8 and 1.5%; LBM, 2.4, 1.8 and 1.5%). In women, rates (%)/100PY of any thromboembolic event were similar for all tertiles of BMI but were highest in the low tertile for BSA and LBM (low, middle, high; BMI, 1.3, 1.1 and 1.1%; BSA, 1.4, 1.1 and 1.0%; LBM, 1.4, 1.2 and 0.9%; Figure 1). For BMI, BSA and LBM, rates (%)/100PY of any haemorrhagic event were highest in the low tertile in women (low, middle, high; BMI, 2.1, 1.6 and 1.6%; BSA, 2.2, 1.7 and 1.4%; LBM, 2.3, 1.5 and 1.5%). Conclusions At the 4-year follow-up in this real-life registry, low rates (%/100PY) of any thromboembolic event ([0.7–1.4%]) were observed regardless of patients' BMI, BSA, LBM, or sex. However, higher rates of any haemorrhagic events were observed in the low ([2.2–2.4%]) vs middle ([1.5–1.8%]) and high ([1.4–1.5%]) tertiles for BSA and LBM, suggesting that these variables, more than BMI, should be considered when analysing outcomes in patients with AF treated with edoxaban.Baseline characteristicsFigure 1

Informing the risk assessment related to lactation and drug exposure: A physiologically based pharmacokinetic lactation model for pregabalin.

Breastfeeding is important in childhood development, and medications are often necessary for lactating individuals, yet information on the potential risk of infant drug exposure through human milk is limited. Establishing a lactation modeling framework can advance our understanding of this topic and potentiate clinical decision making. We expanded the modeling framework previously developed for sotalol using pregabalin as a second prototypical probe compound with similar absorption, distribution, metabolism, and elimination (ADME) properties. Adult oral models were developed in PK-Sim® and used to build a lactation model in MoBi® to simulate drug transfer into human milk. The adult model was applied to breastfeeding pediatrics (ages 1 to 23 months) and subsequently integrated with the lactation model to simulate infant drug exposure according to age, size, and breastfeeding frequency. Physiologically based pharmacokinetic (PBPK) model simulations captured the data used for verification both in adults and pediatrics. Lactation simulations captured observed milk and plasma data corresponding to doses of 150 mg administered twice daily to lactating individuals, and estimated a relative infant dose (RID) of approximately 7% of the maternal dose. The infant drug exposure simulations showed peak plasma concentrations of 0.44 μg/mL occurring within the first 2 weeks of life, followed by gradual decline with age after week four. The modeling framework performs well for this second prototypical drug and warrants expansion to other drugs for further validation. PBPK modeling and simulation approaches together with clinical lactation data could ultimately help inform infant drug exposure risk assessments to guide clinical decision making.

Safety concerns of paternal drug exposure on fertility, pregnancy and offspring: An analysis based on the FDA adverse event reporting system.

Growing evidence indicates that paternal condition significantly influences pregnancy outcomes and offspring health. However, assessing the safety of paternal drug exposure via randomized controlled trials poses ethical challenges, and relevant clinical studies consume a lot of resources to evaluate only a few drugs. Currently, safety data on paternal drug exposure are scarce. To investigate the impact of paternal drug exposure on fertility, pregnancy outcomes, and offspring health. Data from the FDA adverse event reporting system (FAERS) were analyzed (2010-2022). Disproportionality analyses were used to identify signals of each drug-adverse event pair associated with paternal drug exposure in a different hierarchical manner. Out of the 16,180,533 reports, 3210 were related to paternal exposure, encompassing 7808 concomitant adverse events. Drugs used to treat rheumatoid arthritis, cancer, and infections were primary sources of paternal exposure. Analysis identified 115 signals concerning reproductive health. Notably, the signals of diazepam-small for dates baby and finasteride-cryptorchidism were particularly significant (reporting odds ratio, ROR>800, N>10). Moreover, spontaneous abortion signals occur frequently in biologics for the treatment of immune inflammation; the use of immunosuppressive drugs was associated with the highest number of congenital anomalies, with the strongest signals for belatacept-skeletal dysplasia, and tacrolimus-talipes. Only mycophenolic acid, estrogen and imatinib have signals on male fertility. Anti-tumor agents had high numbers of each reproductive toxicity, with the highest values of trisomy 13 signals associated with etoposide and cisplatin. This is the first research to fully assess the safety of paternal exposure to the majority of medications in terms of reproduction. Clinical and scientific researchers should pay close attention to the list of risk medications included in this study, particularly the following association combinations: biologics used to treat inflammatory diseases-abortion, diazepam-small for date baby, finasteride-cryptorchidism, etoposide and cisplatin-13 trisomy.

The relationship between oropharyngeal dysphagia and dehydration in older adults

BackgroundRelationship between dysphagia and dehydration has not been studied widely. The aim of this study is to determine the frequency of dysphagia and dehydration in geriatric outpatient clinic, to evaluate the relationship between these two conditions.MethodsThe cross-sectional study included 1345 patients. Plasma osmolarity (Posm) was calculated using the following formula: [1.86 x (Na + K) + 1.15 x glucose + urea + 14]. Overt dehydration was defined as a calculated Posm of > 300 mmol/L. Eating Assessment Tool (EAT-10) score of ≥ 3 was accepted as dysphagia. Associations between dehydration and dysphagia was evaluated.ResultsMean age was 78 ± 8 years, and 71% were females. Dysphagia was observed in 27% of patients. Dysphagia was associated with a higher number of drug exposure, dependency on basic activities of daily living and geriatric depression (p < 0.05). Overt dehydration was found in 29% of patients with dysphagia, and 21% of patients with no dysphagia (p = 0.002); and dysphagia was significantly associated with overt dehydration mmol/L (OR 1.49, 95% CI 1.13–1.96, p = 0.005) after adjustments for age and sex. In another model, EAT-10 score was found as one of the independent predictors of overt dehydration (OR1.03, 95% CI 1.00-1.06, p = 0.38), along with diabetes mellitus (OR 2.32, 95% CI 1.72–3.15, p < 0.001), chronic kidney disease (OR 3.05, 95% CI 2.24–4.15, p < 0.001), and MNA score (OR 0.97, 95% CI 0.94-1.00, p = 0.031).ConclusionEAT-10 scale was independently associated with overt dehydration among older adults, as MNA score was. Correction of both dysphagia and malnutrition might improve overt dehydration to a better extent than correction either of these factors alone. Future studies are needed to test cause and effect relationships.

Neuroplasticity and Cocaine Exposure During Adolescence

The adolescent brain is particularly vulnerable to the effects of cocaine exposure due to ongoing neurodevelopment especially in areas that are crucial for cognitive and emotional regulation. This review explores the multifaceted impact of cocaine on neuroplasticity during adolescence, thereby highlighting both the immediate and long-term consequences of drug exposure. Key findings from recent studies indicate that cocaine use during adolescence leads to significant alterations in synaptic plasticity, dendritic spine morphology, and neurotransmitter systems, which may persist into adulthood and contribute to addictive behaviors. Additionally, the interaction between genetic predispositions, environmental stressors, and drug exposure is emphasized. The review also analyzed the risks of early-life stress and social isolation on cocaine-induced neuroplasticity, which can render anxiety-related behaviors and lead to neurological changes. Future studies should incorporate longitudinal design to understand the long-term trajectory of neuroplasticity induced by cocaine. This paper can provide some suggestions to the development of prevention and intervention programs for adolescents at risk.

Accelerating adverse pregnancy outcomes research amidst rising medication use: parallel retrospective cohort analyses for signal prioritization

BackgroundPregnant women are significantly underrepresented in clinical trials, yet most of them take medication during pregnancy despite the limited safety data. The objective of this study was to characterize medication use during pregnancy and apply propensity score matching method at scale on patient records to accelerate and prioritize the drug effect signal detection associated with the risk of preterm birth and other adverse pregnancy outcomes.MethodsThis was a retrospective study on continuously enrolled women who delivered live births between 2013/01/01 and 2022/12/31 (n = 365,075) at Providence St. Joseph Health. Our exposures of interest were all outpatient medications prescribed during pregnancy. We limited our analyses to medication that met the minimal sample size (n = 600). The primary outcome of interest was preterm birth. Secondary outcomes of interest were small for gestational age and low birth weight. We used propensity score matching at scale to evaluate the risk of these adverse pregnancy outcomes associated with drug exposure after adjusting for demographics, pregnancy characteristics, and comorbidities.ResultsThe total medication prescription rate increased from 58.5 to 75.3% (P < 0.0001) from 2013 to 2022. The prevalence rate of preterm birth was 7.7%. One hundred seventy-five out of 1329 prenatally prescribed outpatient medications met the minimum sample size. We identified 58 medications statistically significantly associated with the risk of preterm birth (P ≤ 0.1; decreased: 12, increased: 46).ConclusionsMost pregnant women are prescribed medication during pregnancy. This highlights the need to utilize existing real-world data to enhance our knowledge of the safety of medications in pregnancy. We narrowed down from 1329 to 58 medications that showed statistically significant association with the risk of preterm birth even after addressing numerous covariates through propensity score matching. This data-driven approach demonstrated that multiple testable hypotheses in pregnancy pharmacology can be prioritized at scale and lays the foundation for application in other pregnancy outcomes.

A multidisciplinary approach to forensic biological profiling on a single tooth and nail sample.

Analysis of a single tooth and nail can provide valuable forensic information, including year of birth, year of death, age, sex, DNA-profile, geographic residence during childhood and at time of death and drug exposure. The aim is to minimize the amount of used bodily material and to validate the applicability of a multidisciplinary sampling protocol. A nail of the big toe, a tooth and blood of seven deceased individuals were collected postmortem. Collected materials were sampled and segmented in accordance with the multidisciplinary sampling protocol. DNA analysis was conducted on the pulp of the tooth, isotope analysis (Sr, Pb, O and C) on the enamel and 14C-, toxicological and tooth cementum annulation analysis on root segments. DNA-, isotope (Sr, Pb, O and C) -, toxicological-, and 14C -analysis were conducted on toenail segments. The acquired DNA profiles were compared with profiles acquired from blood. Material from seven deceased persons was analysed. 45 out of 56 analyses on dental samples were successful, constituting a success rate of 80%. Additionally, 27 out of 35 analyses were successful on nail samples, yielding a success rate of 77%. DNA-, toxicological and 14C- analyses performed better in nail than in tooth. Isotope analyses performed better in tooth than in nail. A profile with personal characteristics was constructed and matched for 62% of parameters with collected medical information. The performed sampling protocol for simultaneous multidisciplinary forensic analysis on a single tooth and nail sample provided applicable results and valuable information.

PKBOIN-12: A Bayesian Optimal Interval Phase I/II Design Incorporating Pharmacokinetics Outcomes to Find the Optimal Biological Dose.

Immunotherapies and targeted therapies have gained popularity due to their promising therapeutic effects across multiple treatment areas. The focus of early phase dose-finding clinical trials has shifted from finding the maximum tolerated dose (MTD) to identifying the optimal biological dose (OBD), which aims to balance the toxicity and efficacy outcomes, thus optimizing the risk-benefit trade-off. These trials often collect multiple pharmacokinetics (PK) outcomes to assess drug exposure, which has shown correlations with toxicity and efficacy outcomes but has not been utilized in the current dose-finding designs for OBD selection. Moreover, PK outcomes are usually available within days after initial treatment, much faster than toxicity and efficacy outcomes. To bridge this gap, we introduce the innovative model-assisted PKBOIN-12 design, which enhances BOIN12 by integrating PK information into both the dose-finding algorithm and the final OBD determination process. We further extend PKBOIN-12 to TITE-PKBOIN-12 to address the challenges of late-onset toxicity and efficacy outcomes. Simulation results demonstrate that PKBOIN-12 more effectively identifies the OBD and allocates a greater number of patients to it than BOIN12. Additionally, PKBOIN-12 decreases the probability of selecting inefficacious doses as the OBD by excluding those with low drug exposure. Comprehensive simulation studies and sensitivity analysis confirm the robustness of both PKBOIN-12 and TITE-PKBOIN-12 in various scenarios.

Absolute Membrane Protein Abundance of P-gp, BCRP and MRPs in Term Human Placenta Tissue and Commonly Used Cell Systems: Application in PBPK Modeling of Placental Drug Disposition.

The placenta acts as a barrier, excluding noxious substances whilst actively transferring nutrients to the fetus, mediated by various transporters. This study quantified the expression of key placental transporters in term human placenta (n=5) and BeWo, BeWo b30, and JEG-3 placenta cell lines. Combining these results with pregnancy physiologically-based pharmacokinetic (PBPK) modeling, we demonstrate the utility of proteomic analysis for predicting placental drug disposition and fetal exposure. Using targeted proteomics with QconCAT standards, we found significant expression of P-gp, BCRP, MRP2, MRP4, and MRP6 in the human placenta (0.05 - 0.25 pmol/mg membrane protein) with only regional differences observed for P-gp. Unexpectedly, both P-gp and BCRP were below the limit of quantification in the regularly used BeWo cells, indicating that this cell line may not be suitable for the study of placental P-gp and BCRP-mediated transport. In cellular and vesicular overexpression systems, P-gp and BCRP were detectable as expected. Vesicle batches showed consistent P-gp expression correlating with functional activity (N-methyl-quinidine (NMQ) transport). However, BCRP activity (Estrone 3-sulfate (E1S) transport) did not consistently align with expression levels. Incorporating in vitro transporter kinetic data, along with placental transporter abundance, into a PBPK model enabled the evaluation of fetal exposure. Simulation with a hypothetical drug indicated that estimating fetal exposure relies on the intrinsic clearances of relevant transporters. To minimize interlaboratory discrepancies, expression data was generated using consistent proteomic methodologies in the same lab. Integration of this data in pregnancy-PBPK modeling offers a promising tool to investigate maternal, placental and fetal drug exposure. Significance Statement This study quantified the expression of key transporters in human placenta and various placental cell lines, revealing significant expression variations. By integrating these data with PBPK modeling, the study highlights the importance of transporter abundance data in understanding and predicting placental drug disposition.

Isoform-level expression of the constitutive androstane receptor (CAR or NR1I3) transcription factor better predicts the mRNA expression of the cytochrome P450s in human liver samples.

Many factors cause inter-person variability in the activity and expression of liver cytochrome P450 (CYP) drug-metabolizing enzymes, leading to variable drug exposure and treatment outcomes. Several liver-enriched transcription factors (TFs) are associated with CYP expression, with estrogen receptor alpha (ESR1) and constitutive androstane receptor (CAR or NR1I3) being the two top factors. ESR1 and NR1I3 undergo extensive alternative splicing that results in numerous splice isoforms, but how these splice isoforms associate with CYP expression is unknown. Here, we quantified 18 NR1I3 splice isoforms and the three most abundant ESR1 isoforms in 260 liver samples derived from African Americans (AA, n=125) and European Americans (EA, n=135). Our results showed variable splice isoform populations in the liver for both NR1I3 and ESR1. Multiple linear regression analyses revealed that, compared to gene-level NR1I3, isoform-level NR1I3 expression better predicted the mRNA expression of most CYPs and three UDP-glucuronosyltransferases (UGTs), while ESR1 isoforms improved predictive models for the UGTs and CYP2D6, but not for most CYPs. Also, different NR1I3 isoforms were associated with different CYPs, and the associations varied depending on sample ancestry. Surprisingly, non-canonical NR1I3 isoforms having retained introns (introns 2 or 6) were abundantly expressed and associated with the expression of most CYPs and UGTs, whereas the reference isoform (NR1I3-205) only associated with CYP2D6. Moreover, NR1I3 isoform diversity increased during the differentiation of induced pluripotent stem cells to hepatocytes, paralleling increasing CYP expression. These results suggest that isoform-level TF expression may help to explain variation in CYP or UGT expression between individuals. Significance Statement We quantified 18 NR1I3 splice isoforms and three ESR1 splice isoforms in 260 liver samples derived from AA and EA donors and found variable NR1I3 and ESR1 splice isoform expression in the liver. Multiple linear regression analysis showed that, compared to gene-level expression, isoform-level expression of NR1I3 and ESR1 better predicted the mRNA expression of some CYPs and UGTs, highlighting the importance of isoform-level analyses to enhance our understanding of gene transcriptional regulatory networks controlling the expression of drug-metabolizing enzymes.

Lymphoma and Leukemia Cell Vulnerabilities and Resistance Identified by Compound Library Screens.

Response to anticancer agents is often restricted to subsets of patients. Recognition of factors underlying this heterogeneity and identification of biomarkers associated with response to drugs would greatly improve the efficacy of drug treatment. Platforms that can comprehensively map cellular response to compounds in high-throughput provide a unique tool to identify associated biomarkers and provide hypotheses for mechanisms underlying variable response. Such screens can be performed on cell lines and short-term cultures of primary cells to take advantage of the respective models' strength, which include, e.g., the ability to silence genes or introduce somatic mutations to cell lines. Cohorts of patient samples represent the natural diversity of cancers, including rarer mutations and combinatorial patterns of mutations that are often absent from existing cell lines. We here summarize a simple and scalable method for the measurement of viability after drug exposure based on ATP measurements as a surrogate for viability, which we use to measure and understand drug response in cell lines and primary cells.

Phase 2 Trial of Vosoritide Use in Patients with Hypochondroplasia: A Pharmacokinetic/ Pharmacodynamic Analysis.

Vosoritide is a C-type natriuretic peptide (CNP) analog that binds its receptor on chondrocytes, promoting growth by inhibiting the ERK1/2-MAPK pathway. We previously reported the results of a Phase II study in children with hypochondroplasia. Vosoritide led to an average increase in annualized growth velocity (AGV) of 1.81 cm/year and gain of 0.36 in height SD over 12 months. We present here the pharmacokinetic/ pharmacodynamic (PK/PD) data from this study and examine the correlations between these parameters and growth outcomes. We conducted a Phase II trial of daily subcutaneous vosoritide (15 mcg/kg/day) in 24 prepubertal subjects with hypochondroplasia (12 females, mean age 5.9+/-2.3 years, mean height -3.29+0.68 SD). Plasma vosoritide levels were assayed using an electrochemiluminescence assay. Pharmacodynamic markers including serum collagen X biomarker (CXM) and urine cGMP production were measured at Day 1, Month 6 and Month 12 visits. Pearson correlations and regression analyses were performed between PK and PD parameters and growth outcomes. Vosoritide PK parameters were similar to those previously reported in patients with achondroplasia. CXM levels increased from a baseline mean of 22.5±6.5 to 41.6±15.9 ng/ml after 12 months of treatment (p &lt; 0.0001). Urine cGMP increased within 1 hour and peaked at 2 hours after injection. The mean AUC for cGMP production was not significantly different at each study visit. The maximum change in cGMP AUC correlated with PK AUC ((r=0.46, p=0.0001). However, drug exposure, as measured by average PK AUC, did not correlate with any growth outcome. CXM levels correlated with the prior 6-month interval height velocity (partial correlation coefficient=0.40, p=0.0048). However, change in CXM did not correlate with change in height velocity or change in height SD during treatment. Vosoritide treatment showed improvement in AGV and height SD in children with hypochondroplasia. PK analysis indicates that drug exposure was correlated to global CNP activity as measured by urine cGMP but did not correlate with growth outcomes. More studies are needed to identify specific patient characteristics that can predict response to therapy and clinical outcomes.

Population Pharmacokinetic Simulations for Dose Optimization of Tenofovir Disoproxil Fumarate in HIV-Infected Patients with Moderate-to-Severe Renal Impairment.

Tenofovir disoproxil fumarate (TDF) requires dosage adjustments from the standard 300 mg once daily to every 48-96 h for moderate-to-severe renal impairment to avoid excessive exposure. However, this extended interval can lead to variable drug exposure and inconvenience. This study aimed to utilize the population pharmacokinetic (PPK) models to optimize TDF dosing regimens for HIV-infected patients with renal impairment. A systematic literature search was conducted across PubMed, Cochrane Library, and Scopus databases to identify relevant PPK studies of TDF in HIV-infected patients. From the included studies, the PPK models and associated parameters were extracted. Monte Carlo simulations (n = 2000) were performed to generate concentration-time profiles and derive PK parameters compared against reference ranges. For moderate renal impairment, the TDF 150 mg once-daily regimen achieved cumulative exposure comparable to the approved 300 mg every-other-day regimen. In severe renal impairment, TDF 75-100 mg administered once daily provided similar cumulative exposure as 300 mg every 72-96 h regimen while maintaining daily exposure comparable to the standard dose in patients with normal renal function. The approved extended dosing intervals of 72-96 h exhibited high drug exposure variability, initially resulting in supratherapeutic levels followed by suboptimal levels preceding the subsequent dose administration. In conclusion, administering smaller once-daily doses of TDF maintains consistent daily drug exposure comparable to the standard dose in patients with normal renal function while reducing variability in drug exposure, potentially mitigating the risk of nephrotoxicity. However, additional clinical studies are required to confirm these findings.

An Integrated Microcurrent Delivery System Facilitates Human Parathyroid Hormone Delivery for Enhancing Osteoanabolic Effect.

Human parathyroid hormone (1-34) (PTH) exhibits osteoanabolic and osteocatabolic effects, with shorter plasma exposure times favoring bone formation. Subcutaneous injection (SCI) is the conventional delivery route for PTH but faces low delivery efficiency due to limited passive diffusion and the obstruction of the vascular endothelial barrier, leading to prolonged drug exposure times and reduced osteoanabolic effects. In this work, a microcurrent delivery system (MDS) based on multimicrochannel microneedle arrays (MMAs) is proposed, achieving high efficiency and safety for PTH transdermal delivery. The internal microchannels of the MMAs are fabricated using high-precision 3D printing technology, providing a concentrated and safe electric field that not only accelerates the movement of PTH but also reversibly increases vascular endothelial permeability by regulating the actin cytoskeleton and interendothelial junctions through Ca2+-dependent cAMP signaling, ultimately promoting PTH absorption and shortening exposure times. The MDS enhances the osteoanabolic effect of PTH in an osteoporosis model by inhibiting osteoclast differentiation on the bone surface compared to SCI. Moreover, histopathological analysis of the skin and organs demonstrated the good safety of PTH delivered by MDS in vivo. In addition to PTH, the MDS shows broad prospects for the high-efficiency transdermal delivery of macromolecular drugs.

Early Prediction and Impact Assessment of CYP3A4-Related Drug-Drug Interactions for Small-Molecule Anticancer Drugs Using Human-CYP3A4-Transgenic Mouse Models.

Early detection of drug-drug interactions (DDIs) can facilitate timely drug development decisions, prevent unnecessary restrictions on patient enrollment, resulting in clinical study populations that are not representative of the indicated study population, and allow for appropriate dose adjustments to ensure safety in clinical trials. All of these factors contribute to a streamlined drug approval process and enhanced patient safety. Here we describe a new approach for early prediction of the magnitude of change in exposure for cytochrome P450 (P450) CYP3A4-related DDIs of small-molecule anticancer drugs based on the model-based extrapolation of human-CYP3A4-transgenic mice pharmacokinetics to humans. Victim drugs brigatinib and lorlatinib were evaluated with the new approach in combination with the perpetrator drugs itraconazole and rifampicin. Predictions of the magnitude of change in exposure deviated at most 0.99- to 1.31-fold from clinical trial results for inhibition with itraconazole, whereas exposure predictions for the induction with rifampicin were less accurate, with deviations of 0.22- to 0.48-fold. Results for the early prediction of DDIs and their clinical impact appear promising for CYP3A4 inhibition, but validation with more victim and perpetrator drugs is essential to evaluate the performance of the new method. SIGNIFICANCE STATEMENT: The described method offers an alternative for the early detection and assessment of potential clinical impact of CYP3A4-related drug-drug interactions. The model was able to adequately describe the inhibition of CYP3A4 metabolism and the subsequent magnitude of change in exposure. However, it was unable to accurately predict the magnitude of change in exposure of victim drugs in combination with an inducer.