Burden of disease due to transportation noise in the Nordic countries

BACKGROUND

Environmental noise is of increasing concern for public health. Quantification of associated health impacts is important for regulation and preventive strategies.

AIM

To estimate the burden of disease (BoD) due to road traffic and railway noise in four Nordic countries and their capitals, in terms of DALYs (Disability-Adjusted Life Years), using comparable input data across countries.

METHOD

Road traffic and railway noise exposure were obtained from the noise mapping conducted according to the Environmental Noise Directive (END) as well as nationwide noise exposure assessments for Denmark and Norway. Noise annoyance, sleep disturbance and ischaemic heart disease were included as the main health outcomes, using exposure-response functions from the WHO, 2018 systematic review. Additional analyses included stroke and type 2 diabetes. Country-specific DALY rates from the Global Burden of Disease (GBD) study were used as health input data.

RESULTS

Comparable exposure data were not available on a national level for the Nordic countries, only for capital cities. The DALY rates for the capitals ranged from 329 to 485 DALYs/100,000 for road traffic noise and 44 to 146 DALY/100,000 for railway noise. Moreover, the DALY estimates for road traffic noise increased with up to 17% upon inclusion of stroke and diabetes. DALY estimates based on nationwide noise data were 51 and 133% higher than the END-based estimates, for Norway and Denmark, respectively.

CONCLUSION

Further harmonization of noise exposure data is required for between-country comparisons. Moreover, nationwide noise models indicate that DALY estimates based on END considerably underestimate national BoD due to transportation noise. The health-related burden of traffic noise was comparable to that of air pollution, an established risk factor for disease in the GBD framework. Inclusion of environmental noise as a risk factor in the GBD is strongly encouraged.

Parameters influencing population annoyance pertaining to air pollution

Annoyance caused by particulate matter qualifies as a public health problem, as it can be seen as an ambient stressor causing stress, diseases and affecting the quality of life. Previous studies have shown a complex relationship between annoyance and perception of air pollution, health problems occurrences, air pollutants concentration levels and location within the urban area, which should be better investigated. The objective of this work is to identify the parameters that influences perceived annoyance caused by air pollution. Additionally, we propose the analyses of exposure-response relationship between perceived annoyance and concentration levels of particulate matter (TSP and PM₁₀). Questionnaire-based surveys were conducted in sub regions around of the air quality monitoring stations in metropolitan area of Vitoria, Brazil. Logistic regression was used to identify the associations between qualitative questionnaire variables and air pollution expressed by PM concentrations. Results have shown that 90% of the population reports nuisance by air pollution and about 80% of respondents frequently perceived air pollution by dust. The determinants parameters and subjective factors related to particles annoyance perception can be used in order to predict air pollution impact on the studied region population. By exposure-response relationship when the concentration level of PM increases, the probability of being annoyed also grows. The results and the methodology discussed here can be very useful for planning purposes where the stakeholders usually do not have access to detailed information, especially for micro-management in a regional or city-planning level.

Pharmacokinetics and exposure-efficacy relationships of omalizumab in patients with nasal polyps

The anti-immunoglobulin E (IgE) antibody, omalizumab (Xolair), is approved in the United States for the treatment of allergic asthma and chronic spontaneous urticaria, and has recently been studied for the treatment of nasal polyposis following completion of the two replicate phase 3 studies (POLYP 1 and POLYP 2). The dosing of omalizumab used in the phase 3 studies is based on a combination of patients' pre-treatment IgE level and body weight, similar to the approach used in allergic asthma. The objectives of the current analyses were to evaluate whether the pharmacokinetics (PK) of omalizumab and its pharmacodynamic (PD) effect on free and total IgE level in chronic rhinosinusitis with nasal polyps (CRSwNP) are consistent with those in allergic asthma via population PK/PD modeling and simulation, and to graphically explore exposure-response relationships and free IgE-response relationships in CRSwNP. Omalizumab PK and PD effect of total and free IgE in CRSwNP are generally consistent with those in asthma. Observed post-treatment free IgE suppressions were generally within the target range of the baseline IgE- and body weight-based omalizumab dosing table, with 74.2% and 93.0% of patients achieving a serum free IgE level below 25 ng/mL and 50 ng/mL, respectively at Week 24. Exposure-response analyses indicated that there was no clear correlation between omalizumab or free IgE concentration and key efficacy endpoints within the POLYP studies. Overall, these results indicate that the body weight and IgE-based dosing regimen of omalizumab was appropriate for use in CRSwNP patients.

Influence of age on the relationship between apixaban concentration and anti-factor Xa activity in older patients with non-valvular atrial fibrillation

BACKGROUND/OBJECTIVES

Despite lower major bleeding rates associated with direct oral anticoagulants (DOACs) as compared to conventional warfarin therapy, bleeding rates remain higher in older patients compared to younger patients suggesting a potential role for DOAC measurements. The objective of this study is to examine the effect of age on the relationship between apixaban concentrations and anti-Factor Xa activity in patients with non-valvular atrial fibrillation (NVAF).

METHODS

This is a retrospective analysis based on a database created using data from the ARISTOTLE study. Outpatient, stable adult patients with NVAF receiving apixaban were included in this study. Data collection consisted of apixaban concentration, anti-Factor Xa activity, age, weight, creatinine, and co-medications.

RESULTS

The database composed of 2058 patients receiving apixaban. Distribution of race, NVAF subtype, and aspirin use was fairly similar across each age quantile. Older patients received a higher number of co-medications and received the 2.5 mg apixaban dose more often as compared to younger patients (22% vs. < 1%). Linear regression demonstrated that the unadjusted slope for apixaban concentration effect on anti-Factor Xa activity was similar across each age quantile. Although, the overall adjusted linear regression analysis demonstrated that the age by concentration interaction was statistically significant, relative differences in anti-Factor Xa activity (< 8%) were not clinically meaningful.

CONCLUSION

Data on apixaban concentrations and anti-Factor Xa activity from a pivotal randomized double-blind study of apixaban for the prevention of stroke in NVAF patients have confirmed that the chromogenic anti-Factor Xa activity assay can accurately assess apixaban concentrations in patients regardless of age. Age was not associated with a clinically relevant change in the apixaban vs. anti-Factor Xa activity response relationship and target ranges are unchanged.

Antibody-drug conjugates as targeted therapies: Are we there yet? A critical review of the current clinical landscape

Antibody-drug conjugates (ADCs) are targeted therapies with the expectation of broadened therapeutic window due to tumor-specific drug delivery. Recent approvals, including ADCs with a novel payload class, topoisomerase-1 inhibitors, generated renewed excitement in the field. We provide a critical review of approved and late-stage molecules, discuss strategies in solid tumors and ADCs outside oncology. Our pharmacokinetics-based assessment of targeting suggests that ADCs, especially in solid tumors, rely on additional mechanisms for efficacy including slow-release of the payload to the circulation at potentially efficacious levels. Further adjustments in the technology are needed to fulfill the promise of true targeted drug delivery.

Population pharmacokinetic and exposure-response analyses of d-amphetamine after administration of lisdexamfetamine dimesylate in Japanese pediatric ADHD patients

Lisdexamfetamine dimesylate, a prodrug of d-amphetamine, has been approved for treatment of attention-deficit/hyperactivity disorder (ADHD). The purposes of this study were constructing a population pharmacokinetic model of d-amphetamine after dosing of lisdexamfetamine dimesylate and assessing influential factors on the pharmacokinetics of d-amphetamine in Japanese pediatric patients with ADHD. Additionally, the exposure-response relationship was evaluated for Japanese pediatric patients with ADHD using a clinical rating scale, the ADHD Rating Scale IV (ADHD RS-IV, efficacy endpoint) total score as a response index. A total of 1365 points of plasma d-amphetamine concentrations from pediatric patients (6-17 years) with ADHD in clinical studies conducted in Japan and the US were employed for the population pharmacokinetic analysis. The plasma concentrations of d-amphetamine in pediatric patients with ADHD were well described by a one-compartment model with first-order absorption and lag time. The effects of body weight and ethnicity (Japanese or non-Japanese) on apparent total body clearance and the effect of body weight on apparent volume of distribution were incorporated into the final model. No clear exposure-dependent reduction was evident from the ADHD RS-IV total score, whereas the reductions were greater for the lisdexamfetamine dimesylate treatment groups compared with the placebo group regardless of exposure to d-amphetamine.

Research implications of the FDA ECG warehouse and related resources

The electrocardiogram is often used as an efficacy endpoint for comparing new drugs or as an indicator for cardiovascular safety in both studies of arrhythmic and non-arrhythmic novel drugs. The FDA ECG Warehouse data are owned by the submitting entities, generally pharmaceutical company manufacturers. However, a subset of these ECG data was released with permission from the data owners to the CSRC for access by investigators, equipment manufacturers and algorithm developers for CSRC-approved research and development studies. This article provides an overview of the Cardiac Safety Research Consortium (CSRC) ECG Warehouse, including data availability, completed and ongoing projects, as well as future growth potential amidst an ever expanding FDA ECG Warehouse. Given that current ICH E14 guidelines request that sponsors submitting new drug applications assess the effects on the QT interval using a thorough QT (TQT) or dose-ranging study with concentration-QT analysis during early clinical development to assess cardiac risk, developing novel methods to determine cardiovascular safety, as well as understanding current ECG collection and analysis methods are prudent. The ability to utilize previously collected ECG data for secondary analyses improves cardiovascular safety by multiplying the scientific contribution of the original research.

Population pharmacokinetic and exposure-response analyses of guanfacine in Japanese pediatric ADHD patients

Guanfacine hydrochloride extended-release tablet (GXR) is approved for child and adolescent patients with attention-deficit/hyperactivity disorder (ADHD). The aims of this study were to develop a population pharmacokinetic model of guanfacine after administration of GXR and to evaluate factors influencing the pharmacokinetics of guanfacine in pediatric ADHD patients. A population pharmacokinetic analysis was performed using 3231 plasma concentration data items of guanfacine for pediatric ADHD patients aged 6-17 years obtained from clinical studies in Japan and the US. In addition, the relationship of the ADHD Rating Scale IV (ADHD RS-IV, efficacy endpoint) total score with exposure to guanfacine was assessed for Japanese pediatric ADHD patients. A one-compartment model with first-order absorption and lag time well described the plasma concentration data of guanfacine in pediatric ADHD patients. Body weight was selected as a covariate of apparent total body clearance and apparent volume of distribution. There was no pharmacokinetic difference between Japanese and non-Japanese pediatric ADHD patients. The results suggested a tendency of exposure-dependent reduction in the ADHD RS-IV total score, whereas the reduction was observed even at low plasma exposure levels compared with the placebo group.

Bayesian network-based framework for exposure-response study design and interpretation

Conventional environmental-health risk-assessment methods are often limited in their ability to account for uncertainty in contaminant exposure, chemical toxicity and resulting human health risk. Exposure levels and toxicity are both subject to significant measurement errors, and many predicted risks are well below those distinguishable from background incident rates in target populations. To address these issues methods are needed to characterize uncertainties in observations and inferences, including the ability to interpret the influence of improved measurements and larger datasets. Here we develop a Bayesian network (BN) model to quantify the joint effects of measurement errors and different sample sizes on an illustrative exposure-response system. Categorical variables are included in the network to describe measurement accuracies, actual and measured exposures, actual and measured response, and the true strength of the exposure-response relationship. Network scenarios are developed by fixing combinations of the exposure-response strength of relationship (none, medium or strong) and the accuracy of exposure and response measurements (low, high, perfect). Multiple cases are simulated for each scenario, corresponding to a synthetic exposure response study sampled from the known scenario population. A learn-from-cases algorithm is then used to assimilate the synthetic observations into an uninformed prior network, yielding updated probabilities for the strength of relationship. Ten replicate studies are simulated for each scenario and sample size, and results are presented for individual trials and their mean prediction. The model as parameterized yields little-to-no convergence when low accuracy measurements are used, though progressively faster convergence when employing high accuracy or perfect measurements. The inferences from the model are particularly efficient when the true strength of relationship is none or strong with smaller sample sizes. The tool developed in this study can help in the screening and design of exposure-response studies to better anticipate where such outcomes can occur under different levels of measurement error. It may also serve to inform methods of analysis for other network models that consider multiple streams of evidence from multiple studies of cumulative exposure and effects.

Assessing the exposure-response relationship of sleep disturbance and vibration in field and laboratory settings

Exposure to nocturnal freight train vibrations may impact sleep, but exposure-response relationships are lacking. The European project CargoVibes evaluated sleep disturbance both in the field and in the laboratory and provides unique data, as measures of response and exposure metrics are comparable. This paper therefore provides data on exposure-response relationships of vibration and sleep disturbance and compares the relationships evaluated in the laboratory and the field. Two field studies (one in Poland and one in the Netherlands) with 233 valid respondents in total, and three laboratory studies in Sweden with a total of 59 subjects over 350 person-nights were performed. The odds ratios (OR) of sleep disturbance were analyzed in relation to nighttime vibration exposure by ordinal logit regression, adjusting for moderating factors common for the studies. Outcome specific fractions were calculated for eleven sleep outcomes and supported comparability between the field and laboratory settings. Vibration exposure was significantly associated with sleep disturbance, OR = 3.51 (95% confidence interval 2.6-4.73) denoting a three and a half times increase in the odds of sleep disturbance with one unit increased 8 h nighttime log10 Root Mean Square vibration. The results suggest no significant difference between field and laboratory settings OR = 1.37 (0.59-3.19). However, odds of sleep disturbance were higher in the Netherlands as compared to Sweden, indicating unexplained differences between study populations or countries, possibly related to cultural and contextual differences and uncertainties in exposure assessments. Future studies should be carefully designed to record explanatory factors in the field and enhance ecological validity in the laboratory. Nevertheless, the presented combined data set provides a first set of exposure response relationships for vibration-induced sleep disturbance, which are useful when considering public health outcomes among exposed populations.

Population pharmacokinetics and exposure-response assessment of veliparib co-administered with temozolomide in patients with myeloid leukemias

PURPOSE

Veliparib is an oral inhibitor of poly(ADP-ribose) polymerase enzyme. Combination of veliparib and temozolomide was well-tolerated and demonstrated clinical activity in older patients with relapsed or refractory acute myeloid leukemia (AML) or AML arising from pre-existing myeloid malignancies. We aimed to perform quantitative assessments of pharmacokinetics, efficacy, and safety of veliparib in this patient population to inform future trial design.

METHODS

Population pharmacokinetic analysis was performed using Phoenix^® NLME with pharmacokinetic data obtained from 37 subjects after oral administration of veliparib in a Phase I study with and without temozolomide. Effect of covariates (age, sex, BMI, creatinine clearance (CL_CR), and co-administration of temozolomide) on the pharmacokinetics of veliparib were evaluated, as well as impact of veliparib exposure on mucositis (dose-limiting toxicity), objective response rate (ORR), and overall survival.

RESULTS

A two-compartment model with first-order elimination and a first-order absorption with lag-time adequately described veliparib pharmacokinetics. CL_CR and body weight were clinically significant covariates for veliparib disposition. The proportion of subjects with all grade mucositis increased with veliparib exposure (AUC). However, no trend in ORR and overall survival was observed with increasing exposure.

CONCLUSIONS

Veliparib with temozolomide presents a promising combination for older patients with myeloid leukemias. An exposure-safety relationship was established for this combination. Further clinical investigations aimed at elucidating the veliparib exposure-efficacy/safety relationship and optimizing dosing recommendations for maximizing benefit-risk in patients with advanced myeloid malignancies should study veliparib doses ranging up to 120 mg in combination with temozolomide.

Statistical software for analyzing the health effects of multiple concurrent exposures via Bayesian kernel machine regression

BACKGROUND

Estimating the health effects of multi-pollutant mixtures is of increasing interest in environmental epidemiology. Recently, a new approach for estimating the health effects of mixtures, Bayesian kernel machine regression (BKMR), has been developed. This method estimates the multivariable exposure-response function in a flexible and parsimonious way, conducts variable selection on the (potentially high-dimensional) vector of exposures, and allows for a grouped variable selection approach that can accommodate highly correlated exposures. However, the application of this novel method has been limited by a lack of available software, the need to derive interpretable output in a computationally efficient manner, and the inability to apply the method to non-continuous outcome variables.

METHODS

This paper addresses these limitations by (i) introducing an open-source software package in the R programming language, the bkmr R package, (ii) demonstrating methods for visualizing high-dimensional exposure-response functions, and for estimating scientifically relevant summaries, (iii) illustrating a probit regression implementation of BKMR for binary outcomes, and (iv) describing a fast version of BKMR that utilizes a Gaussian predictive process approach. All of the methods are illustrated using fully reproducible examples with the provided R code.

RESULTS

Applying the methods to a continuous outcome example illustrated the ability of the BKMR implementation to estimate the health effects of multi-pollutant mixtures in the context of a highly nonlinear, biologically-based dose-response function, and to estimate overall, single-exposure, and interactive health effects. The Gaussian predictive process method led to a substantial reduction in the runtime, without a major decrease in accuracy. In the setting of a larger number of exposures and a dichotomous outcome, the probit BKMR implementation was able to correctly identify the variables included in the exposure-response function and yielded interpretable quantities on the scale of a latent continuous outcome or on the scale of the outcome probability.

CONCLUSIONS

This newly developed software, integrated suite of tools, and extended methodology makes BKMR accessible for use across a broad range of epidemiological applications in which multiple risk factors have complex effects on health.

Exposures to fine particulate matter (PM2.5) and birthweight in a rural-urban, mother-child cohort in Tamil Nadu, India

BACKGROUND

Exposure to PM_2.5 (fine particulate matter <less than 2.5µm in aerodynamic diameter) related to ambient and household air pollution has been associated with low birthweight. Few of these studies, however, have been conducted in high exposure settings that are commonly encountered in low and middle income countries (LMICs).

OBJECTIVES

We examined whether PM_2.5 exposures during pregnancy were associated with birthweight in an integrated rural-urban, mother-child cohort in the state of Tamil Nadu, India.

METHODS

We recruited 1285 pregnant women in the first trimester of pregnancy from primary health care centers and urban health posts and followed them until birth to collect antenatal care data and birthweight. We estimated pregnancy period PM _2.5 exposures through direct serial measurements of 24-h household PM_2.5 concentrations, performed across each trimester. Mothers also completed detailed questionnaires to provide data on covariates related to household, socio-economic, demographic and maternal health characteristics. The association between PM_2.5 exposures and birth weight was assessed using linear and logistic regression models that controlled for potential confounders.

RESULTS

A 10-μg/m³ increase in pregnancy period PM_2.5 exposures was associated with a 4g (95% CI: 1.08g, 6.76g) decrease in birthweight and 2% increase in prevalence of low birthweight [odds ratio(OR) = 1.02; 95%CI:1.005,1.041] after adjusting for gestational age, infant sex, maternal BMI, maternal age, history of a previous low birth weight child, birth order and season of conception.

CONCLUSIONS

The study provides some of the first quantitative effects estimates for linking rural-urban PM_2.5 exposures and birthweight in India, adding important evidence for this association from high exposure settings in LMICs, that also experience dual health burdens from ambient and household air pollution. Study results also point to the need for considering maternal PM_2.5 exposures alongside other risk factors for low birthweight in India.

Model-based clinical pharmacology profiling and exposure-response relationships of the efficacy and biomarker of lebrikizumab in patients with moderate-to-severe asthma

Lebrikizumab is a humanized monoclonal antibody that binds to interleukin-13 and has been evaluated as a treatment for moderate-to-severe asthma. Objectives of this work were to characterize lebrikizumab pharmacokinetics (PK), identify influential covariates, and graphically explore exposure-response relationships in moderate-to-severe asthmatics. Pooled PK data from 11 studies were used in the population PK model development. Full covariate modeling was used to evaluate the impact of pre-specified covariates. Response data (exacerbation rate, forced expiratory volume in 1 s [FEV₁], and fractional exhaled nitric oxide [FeNO]) were obtained from moderate-to-severe asthmatics (n = 2148) who received placebo, lebrikizumab 37.5 mg or 125 mg every 4 weeks (Q4W) in two replicate phase 3 studies. Graphical exposure-response analyses were stratified by numerous covariates, including biomarker subgroups defined by serum periostin level and blood eosinophil count at baseline. Lebrikizumab PK was described by a two-compartment model with first-order absorption. Population typical values were estimated as 0.156 L/day for clearance (CL), 4.10 L for central volume (Vc), and 0.239 day^-1 for absorption rate (ka), 85.6% for bioavailability (inter-subject variability: CL, 33.3%; Vc, 36.3%; ka, 40.8%). The estimated mean terminal half-life was 25.7 days. Body weight was the most influential covariate. Generally, the exposure-response analyses of FEV₁ and FeNO showed increased response at higher exposure quartiles, while flat or unclear exposure-response relationships were observed in exacerbation rate. Lebrikizumab PK is as expected for a typical immunoglobulin G4 monoclonal antibody. Results from the exposure-response analyses suggested that, compared to 125 mg Q4W, the 37.5 mg Q4W dose did not achieve the maximum responses for FEV₁ and FeNO, although it appeared to maximize the effect on exacerbation reduction. This suggests that the antibody levels needed to improve these outcomes may not be the same. In addition, the role of IL-13 in airflow obstruction/airway inflammation and asthma exacerbations might be different and targeting multiple pathways may be required to treat this heterogeneous disease and provide clinically meaningful benefits to asthma patients.

Metals, hormones and sexual maturation in Flemish adolescents in three cross-sectional studies (2002-2015)

Sex hormone levels and timing of sexual maturation are considered important markers for health status of adolescents in puberty, and previous research suggests they might be influenced by metal exposure. In three campaigns of the Flemish Environment and Health Study (FLEHS I 2002-2006; FLEHS II 2007-2011 and FLEHS III 2012-2015), data were collected on internal exposure to metals (Cd, Cu, Pb, Cr, Mn, Tl, Ni, Sb, Hg, As and As species) and sexual maturation in 2671 14-15years old adolescents. All metals were measured in blood and/or urine, except total- and methylmercury which were measured in hair samples. Sex hormone levels were measured in blood serum of adolescent males of the cohorts of FLEHS I and FLESH II. The use of a uniform methodology in successive campaigns allows to confirm associations between exposure and health in different cohorts and over time. Furthermore, mathematical and statistical density correction methods using creatinine or specific gravity were tested for urinary markers. Significant associations between sex hormones and maturity markers were observed in the FLEHS I and II campaigns, when both were assessed together. Regardless of the applied correction method, creatinine correction systematically introduced bias due to associations of creatinine with sex hormones and maturation markers, especially in adolescent males, while this is not the case for specific gravity. A series of exposure-response associations were found, but several involving Cd, Pb, As, Tl and Cu persisted in different FLEHS campaigns. The effects of Pb and Cu on luteinizing hormone, (free) testosterone, (free) oestradiol and maturation support a xenoestrogenic agonistic action on the feedback of oestradiol to the hypothalamus-pituitary-gonadal axis. Our results suggest that specific care should be taken when selecting urine density correction for investigating associations with hormonal and maturation markers in adolescent males. Furthermore, the possibility of xenoestrogenic effects of certain metals in environmentally exposed adolescents warrants further investigation.

Comparable pharmacodynamics, efficacy, and safety of linagliptin 5 mg among Japanese, Asian and white patients with type 2 diabetes

Aims/Introduction

The efficacy and safety of drugs can vary between different races or ethnic populations because of differences in the relationship of dose to exposure, pharmacodynamic response or clinical efficacy and safety. In the present post‐hoc analysis, we assessed the influence of race on the pharmacokinetics, pharmacodynamics, efficacy and safety of monotherapy with the dipeptidyl peptidase‐4 inhibitor, linagliptin, in patients with type 2 diabetes enrolled in two comparable, previously reported randomized phase III trials.

Materials and Methods

Study 1 (with a 12‐week placebo‐controlled phase) recruited Japanese patients only (linagliptin, n = 159; placebo, n = 80); study 2 (24‐week trial) enrolled Asian (non‐Japanese; linagliptin, n = 156; placebo, n = 76) and white patients (linagliptin, n = 180; placebo, n = 90).

Results

Linagliptin trough concentrations were equivalent across study and race groups, and were higher than half‐maximal inhibitory concentration, resulting in dipeptidyl peptidase‐4 inhibition >80% at trough. Linagliptin inhibited plasma dipeptidyl peptidase‐4 activity to a similar degree in study 1 and study 2. Linagliptin reduced fasting plasma glucose concentrations by a similar magnitude across groups, leading to clinically relevant reductions in glycated hemoglobin in all groups. Glycated hemoglobin levels decreased to a slightly greater extent in study 1 (Japanese) and in Asian (non‐Japanese) patients from study 2. Linagliptin had a favorable safety profile in each race group.

Conclusions

Trough exposure, pharmacodynamic response, and efficacy and safety of linagliptin monotherapy were comparable among Japanese, Asian (non‐Japanese) and white patients, confirming that the recommended 5‐mg once‐daily dose of linagliptin is appropriate for use among different race groups.

Liraglutide pharmacokinetics and dose-exposure response in Asian subjects with Type 2 diabetes from China, India and South Korea

AIMS

To investigate the population pharmacokinetics and exposure-response relationship of liraglutide, a human glucagon-like peptide-1 (GLP-1) analogue, in Asian subjects with Type 2 diabetes mellitus.

METHODS

Data were derived from a published 16-week, randomized, double-blind, double-dummy, active-controlled, parallel-group trial of liraglutide in China, India and South Korea. The analysis utilized 2061 pharmacokinetic (PK) samples from 605 subjects exposed to liraglutide 0.6, 1.2 or 1.8 mg once daily. Demographic factors (body weight, age, gender, country) of importance for liraglutide clearance were evaluated. An exploratory exposure-response analysis was conducted to investigate effects on glycated haemoglobin (HbA1c) and body weight.

RESULTS

Estimated liraglutide exposure (area under the curve; AUC) appeared to increase proportionally with increasing liraglutide dose (0.6-1.8 mg). The covariate analysis confirmed previous findings in a global clinical trial. Body weight was a predictor of liraglutide exposure; compared to a reference subject of 67 kg, exposure was 32% lower for maximum (115 kg) and 54% higher for minimum (37 kg) observed body weights. Gender, age and country had no relevant effect on exposure. Exposure-response analysis supported the use of 1.2mg as maintenance dose with the option of individual dose escalation to 1.8 mg to optimize treatment outcomes.

CONCLUSIONS

Exposure appeared to increase proportionally with increasing liraglutide dose in Asian subjects with Type 2 diabetes mellitus. The only PK relevant predictor of exposure was body weight. The exposure-response relationships for HbA1c and body weight in Asian subjects were similar to observations in global populations.

Using sparse dose-response data for wildlife risk assessment

Hazard quotients based on a point-estimate comparison of exposure to a toxicity reference value (TRV) are commonly used to characterize risks for wildlife. Quotients may be appropriate for screening-level assessments but should be avoided in detailed assessments, because they provide little insight regarding the likely magnitude of effects and associated uncertainty. To better characterize risks to wildlife and support more informed decision making, practitioners should make full use of available dose-response data. First, relevant studies should be compiled and data extracted. Data extractions are not trivial--practitioners must evaluate the potential use of each study or its components, extract numerous variables, and in some cases, calculate variables of interest. Second, plots should be used to thoroughly explore the data, especially in the range of doses relevant to a given risk assessment. Plots should be used to understand variation in dose-response among studies, species, and other factors. Finally, quantitative dose-response models should be considered if they are likely to provide an improved basis for decision making. The most common dose-response models are simple models for data from a particular study for a particular species, using generalized linear models or other models appropriate for a given endpoint. Although simple models work well in some instances, they generally do not reflect the full breadth of information in a dose-response data set, because they apply only for particular studies, species, and endpoints. More advanced models are available that explicitly account for variation among studies and species, or that standardize multiple endpoints to a common response variable. Application of these models may be useful in some cases when data are abundant, but there are challenges to implementing and interpreting such models when data are sparse.