Lymphatic distribution considerations for subunit vaccine design and development

Subunit vaccines are an important platform for controlling current and emerging infectious diseases. The lymph nodes are the primary site generating the humoral response and delivery of antigens to these sites is critical to effective immunization. Indeed, the duration of antigen exposure within the lymph node is correlated with the antibody response. While current licensed vaccines are typically given through the intramuscular route, injecting vaccines subcutaneously allows for direct access to lymphatic vessels and therefore can enhance the transfer of antigen to the lymph nodes. However, protein subunit antigen uptake into the lymph nodes is inefficient, and subunit vaccines require adjuvants to stimulate the initial immune response. Therefore, formulation strategies have been developed to enhance the exposure of subunit proteins and adjuvants to the lymph nodes by increasing lymphatic uptake or prolonging the retention at the injection site. Given that lymph node exposure is a crucial consideration in vaccine design, in depth analyses of the pharmacokinetics of antigens and adjuvants should be the focus of future preclinical and clinical studies. This review will provide an overview of formulation strategies for targeting the lymphatics and prolonging antigen exposure and will discuss pharmacokinetic evaluations which can be applied toward vaccine development.

Second-line antituberculosis drug exposure thresholds predictive of adverse events in multidrug-resistant tuberculosis treatment

OBJECTIVES

This study aimed to investigate the association between drug exposure and adverse events (AEs) during the standardized multidrug-resistant tuberculosis (MDR-TB) treatment, as well as to identify predictive drug exposure thresholds.

METHODS

We conducted a prospective, observational multicenter study among participants receiving standardized MDR-TB treatment between 2016 and 2019 in China. AEs were monitored throughout the treatment and their relationships to drug exposure (e.g., the area under the drug concentration-time curve from 0 to 24 h, AUC0-24 h) were analyzed. The thresholds of pharmacokinetic predictors of observed AEs were identified by boosted classification and regression tree (CART) and further evaluated by external validation.

RESULTS

Of 197 study participants, 124 (62.9%) had at least one AE, and 15 (7.6%) experienced serious AEs. The association between drug exposure and AEs was observed including bedaquiline, its metabolite M2, moxifloxacin and QTcF prolongation (QTcF >450 ms), linezolid and mitochondrial toxicity, cycloserine and psychiatric AEs. The CART-derived thresholds of AUC0-24 h predictive of the respective AEs were 3.2 mg·h/l (bedaquiline M2); 49.3 mg·h/l (moxifloxacin); 119.3 mg·h/l (linezolid); 718.7 mg·h/l (cycloserine).

CONCLUSIONS

This study demonstrated the drug exposure thresholds predictive of AEs for key drugs against MDR-TB treatment. Using the derived thresholds will provide the knowledge base for further randomized clinical trials of dose adjustment to minimize the risk of AEs.

Prospective study to characterize adalimumab exposure in pediatric patients with rheumatic diseases

BACKGROUND

In pediatric rheumatic diseases (PRD), adalimumab is dosed using fixed weight-based bands irrespective of methotrexate co-treatment, disease activity (DA) or other factors that might influence adalimumab pharmacokinetics (PK). In rheumatoid arthritis (RA) adalimumab exposure between 2-8 mg/L is associated with clinical response. PRD data on adalimumab is scarce. Therefore, this study aimed to analyze adalimumab PK and its variability in PRD treated with/without methotrexate.

METHODS

A two-center prospective study in PRD patients aged 2-18 years treated with adalimumab and methotrexate (GA-M) or adalimumab alone (GA) for ≥ 12 weeks was performed. Adalimumab concentrations were collected 1-9 (maximum concentration; Cmax), and 10-14 days (minimum concentration; Cmin) during ≥ 12 weeks following adalimumab start. Concentrations were analyzed with enzyme-linked immunosorbent assay (lower limit of quantification: 0.5 mg/L). Log-normalized Cmin were compared between GA-M and GA using a standard t-test.

RESULTS

Twenty-eight patients (14 per group), diagnosed with juvenile idiopathic arthritis (71.4%), non-infectious uveitis (25%) or chronic recurrent multifocal osteomyelitis (3.6%) completed the study. GA-M included more females (71.4%; GA 35.7%, p = 0.13). At first study visit, children in GA-M had a slightly longer exposure to adalimumab (17.8 months [IQR 9.6, 21.6]) compared to GA (15.8 months [IQR 8.5, 30.8], p = 0.8). Adalimumab dosing was similar between both groups (median dose 40 mg every 14 days) and observed DA was low. Children in GA-M had a 27% higher median overall exposure compared to GA, although median Cmin adalimumab values were statistically not different (p = 0.3). Cmin values ≥ 8 mg/L (upper limit RA) were more frequently observed in GA-M versus GA (79% versus 64%). Overall, a wide range of Cmin values was observed in PRD (0.5 to 26 mg/L).

CONCLUSION

This study revealed a high heterogeneity in adalimumab exposure in PRD. Adalimumab exposure tended to be higher with methotrexate co-treatment compared to adalimumab monotherapy although differences were not statistically significant. Most children showed adalimumab exposure exceeding those reported for RA with clinical response, particularly with methotrexate co-treatment. This highlights the need of further investigations to establish model-based personalized treatment strategies in PRD to avoid under- and overexposure.

TRIAL REGISTRATION

NCT04042792 , registered 02.08.2019.

Dose-sparing effect of lapatinib co-administered with a high-fat enteral nutrition emulsion: preclinical pharmacokinetic study

Background

Lapatinib is an oral small-molecule tyrosine kinase inhibitor indicated for advanced or metastatic HER2-positive breast cancer. In order to reduce the treatment cost, a high-fat enteral nutrition emulsion TPF-T was selected as a dose-sparing agent for lapatinib-based therapies. This study aimed to investigate the effect of TPF-T on lapatinib pharmacokinetics.

Methods

First, a simple and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed to quantitatively evaluate lapatinib in rabbit plasma. The method was fully validated according to the China Pharmacopoeia 2020 guidance. Rabbits and rats were chosen as the animal models due to their low and high bile flows, respectively. The proposed LC-MS/MS method was applied to pharmacokinetic studies of lapatinib, with or without TPF-T, in rabbit and rat plasma.

Results

The LC-MS/MS method revealed high sensitivity and excellent efficiency. In the rabbit model, co-administration with TPF-T resulted in a 32.2% increase in lapatinib exposure. In the rat model, TPF-T had minimal influence on the lapatinib exposure. In both models, TPF-T was observed to significantly elevate lapatinib concentration in the absorption phase.

Conclusion

Co-administration with TPF-T had a moderate effect on increasing exposure to lapatinib. Dose sparing using a high-fat liquid diet is potentially feasible for lapatinib-based therapies.

Interferon-beta exposure in-utero and the risk of infections in early childhood

BACKGROUND

Knowledge within the field of multiple sclerosis treatment during pregnancy is vital to ensure the most optimal clinical practice. Immunomodulatory treatment in pregnancy could in theory affect the normal development and maturation of the immune system of the fetus with a potential increased risk of infections, consequently. We therefore set out to investigate whether exposure to interferon-beta in utero affected the risk of acquiring infections in early childhood.

METHODS

This retrospective matched cohort study utilized data from the Danish Multiple Sclerosis Registry linked with national Danish registries to identify all children born of mothers with MS in Denmark from 1998 to 2018. The study included 510 children exposed to interferon-beta in utero. The children were matched 1:1 on various of demographic characteristics with children born to mothers with untreated MS and 1:3 with children born to mothers without MS. Each child was followed for up to five years. Using individual-level data, we investigated all-cause mortality, rate of hospital admissions due to infections, and redeemed prescriptions of antibiotics. The primary statistical model applied was a negative binomial regression analysis.

RESULTS

We found no differences in childhood mortality, for hospital admissions the rate ratio compared to healthy controls was 0.79 (0.62-1.00). Regarding antibiotic prescriptions, the results were similar (RR 1.00 (0.90-1.11). Furthermore, we found no certain dose-response relationship between interferon-beta exposure duration and hospital admission rate (P = 0.47) or redeemed antibiotic prescription (P = 0.71).

CONCLUSION

Exposure to interferon-beta during gestation has little to no impact on the risk of acquiring significant infections during the first five years of childhood.

Safety of medicines during breastfeeding - from case report to modeling : A contribution from the ConcePTION project

INTRODUCTION

Despite many research efforts, current data on the safety of medicines during breastfeeding are either fragmented or lacking, resulting in restrictive labeling of most medicines. In the absence of pharmacoepidemiologic safety studies, risk estimation for breastfed infants is mainly derived from pharmacokinetic (PK) information on the medicine. This manuscript provides a description and a comparison of the different methodological approaches that can yield reliable information on medicine transfer into human milk and the resulting infant exposure.

AREA COVERED

Currently, most information on medicine transfer in human milk relies on case reports or traditional PK studies, which generate data that can hardly be generalized to the population. Some methodological approaches, such as population PK (popPK) and physiologically-based PK (PBPK) modeling, can be used to provide a more complete characterization of infant medicine exposure through human milk and simulate the most extreme situations, while decreasing the burden of sampling in breastfeeding women.

EXPERT OPINION

PBPK and popPK modeling are promising approaches to fill the gap of knowledge in medicine safety in breastfeeding, as illustrated with our escitalopram example.

A case series evaluation of comprehensive drug testing in the pediatric acute care setting

Introduction

Drug testing typically follows a one-size-fits-all approach that is inadequate in some clinical scenarios, such as child maltreatment, neglect, and unintentional drug exposure. Results from immunoassay-based testing, which are non-specific, insensitive, and far from comprehensive, can lead to unintended consequences for children and their families.

Objectives

The objective of this retrospective case series study is to evaluate the utility of real-time (0-1 day) comprehensive drug testing as an alternative to immunoassay-based testing in the pediatric acute care setting.

Methods

Comprehensive drug testing results obtained by mass spectrometry testing and associated medical data for all pediatric cases (0-12 years) at one institution from 2019 to 2022 were included in the analysis. The final case series (n = 7) included all cases from patients <3 years with comprehensive drug testing results that were inconsistent with medication history and/or toxicology results by immunoassay.

Results

Comprehensive drug testing by mass spectrometry was ordered for 174 urine and blood samples representing 97 patients (0-12 years) from 2019 to 2022. Of these, 76 cases were from patients <3 years old; results were consistent with medication history and confirmatory for immunoassay results (n = 34), consistent with medication history (n = 14), confirmatory for immunoassay results (n = 10), negative (n = 9), or medical history was incomplete (n = 2). The remaining 7 cases were included in the final case series.

Conclusions

The cases highlight the value of real-time comprehensive drug testing in acute pediatric cases. Testing results can rule out toxic exposure from the diagnostic differential when negative, and lead to appropriate medical and social interventions when positive.

Proactive therapeutic drug monitoring of vincristine in pediatric and adult cancer patients: current supporting evidence and future efforts

Vincristine (VCR), an effective antitumor drug, has been utilized in several polytherapy regimens for acute lymphoblastic leukemia, neuroblastoma and rhabdomyosarcoma. However, clinical evidence shows that the metabolism of VCR varies greatly among patients. The traditional based body surface area (BSA) administration method is prone to insufficient exposure to VCR or severe VCR-induced peripheral neurotoxicity (VIPN). Therefore, reliable strategies are urgently needed to improve efficacy and reduce VIPN. Due to the unpredictable pharmacokinetic changes of VCR, therapeutic drug monitoring (TDM) may help to ensure its efficacy and to manage VIPN. At present, there is a lot of supporting evidence for the suitability of applying TDM to VCR therapy. Based on the consensus guidelines drafted by the International Association of Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT), this review aimed to summarize various available data to evaluate the potential utility of VCR TDM for cancer patients. Of note, valuable evidence has accumulated on pharmacokinetics variability, pharmacodynamics, drug exposure-clinical response relationship, biomarkers for VIPN prediction, and assays for VCR monitoring. However, there are still many relevant clinical pharmacological questions that cannot yet be answered merely based on insufficient evidence. Currently, we cannot recommend a therapeutic exposure range and cannot yet provide a dose-adaptation strategy for clinicians and patients. In areas where the evidence is not yet sufficient, more research is needed in the future. The precision medicine of VCR cannot rely on TDM alone and needs to consider the clinical, environmental, genetic background and patient-specific factors as a whole.

Non-uniformity in in vitro drug-induced cytotoxicity as evidenced by differences in IC50 values - implications and way forward

Cell lines have proven indispensable for in vitro experiments and their utility as experimental models range from understanding the fundamental cell functioning to drug discovery. One of the most common utility of cell lines is for in vitro drug testing. Drug testing involves determining the cytotoxic effects of the drugs and such a measurement is expressed as the IC₅₀ values of drugs. Although determination of IC₅₀ values of drugs on cell lines is one of the most common in vitro experimental approaches, a significant amount of variations can be observed in the results obtained from such studies. Although the variations in the IC₅₀ values of a drug on different cells lines can and should vary, the non-uniformity of such results reported from different studies using a particular drug on a specific cell line is a matter of concern. We present the IC₅₀ values of 5 most commonly used drugs 5-fluorouracil, bleomycin, cisplatin, doxorubicin and methotrexate obtained from several in vitro cell line-based studies. Some of the factors which contribute to the non-uniformity of the IC₅₀ values for a particular drug from different studies are discussed as three types of factors, the biological, non-biological and human factors. Also, ways in which such variations can be reduced to obtain universally common, reliable results are presented.

Breastfeeding recommendations for women taking anti-seizure medications

The literature regarding breastfeeding and effects of anti-seizure medication (ASM) exposure on the breastfed infant has been evolving rapidly over the last decade as new studies advance our understanding of the extent of medication exposure via breastfeeding and the long-term developmental outcomes of breastfed infants. Currently, strong evidence supports the safety of breastfeeding for women with epilepsy (WWE) taking most prescribed ASMs. In this review, we present a comprehensive overview of the data regarding ASM exposure in breastfed infants and neurodevelopmental outcomes in breastfed infants of mothers taking various ASMs. In addition, we present current breastfeeding recommendations and the reported adverse effects of various ASMs to facilitate decision making in the clinical care of WWE.

Does Monitoring Total and Free Polymyxin B1 Plasma Concentrations Predict Polymyxin B-Induced Nephrotoxicity? A Retrospective Study in Critically Ill Patients

INTRODUCTION

The correlation between total and free polymyxin B (PMB including PMB1 and PMB2) exposure in vivo and acute kidney injury (AKI) remains obscure. This study explores the relationships between plasma exposure of PMB1 and PMB2 and nephrotoxicity, and investigates the risk factors for PMB-induced acute kidney injury (AKI) in critically ill patients.

METHODS

Critically ill patients who used PMB and met the criteria were enrolled. The total plasma concentration and plasma binding of PMB1 and PMB2 were analysed by liquid chromatography-tandem mass spectrometry and equilibrium dialysis.

RESULTS

A total of 89 patients were finally included, and AKI developed in 28.1% of them. The peak concentration of PMB1 (C_max (B1)) (adjusted odds ratio (AOR) = 1.68, 95% CI 1.08-2.62, p = 0.023), baseline BUN level (AOR = 1.08, 95% CI 1.01-1.16, p = 0.039) and hypertension (AOR = 3.73, 95% CI 1.21-11.54, p = 0.022) were independent risk factors for PMB-induced AKI. The area under the ROC curve of the model was 0.799. When C_max (B1) was 5.23 μg/ml or more, the probability of AKI was higher than 50%. The ratio of PMB1/PMB2 decreased after PMB preparation entered into the body. The protein binding rate in critically ill patients indicated significant individual differences. Free C_max (B) and free C_max (B1) levels in the AKI group were significantly (p < 0.05) higher than those in the non-AKI group. Total and free concentrations of PMB in patients showed a positive correlation.

CONCLUSIONS

Both the ROC curve and logistic regression model showed that C_max (B1) was a good predictor for the probability of PMB-induced AKI. Early therapeutic drug monitoring (TDM) of PMB should be considered in critically ill patients. Compared with C_min (B), C_max (B) and C_max (B1) may be helpful for the early prediction of PMB-induced AKI in critically ill patients.

Ocfentanil testing in hair from a fatality case: Comparative analysis of a lock of hair versus a single hair fiber

In clinical and forensic toxicology, hair analysis offers a larger window for detecting drug exposure than blood or urine. Drug measurements are generally carried out using a segmented lock of hair, but few articles report the use of a single hair to document drug exposure. Nevertheless, single hair analysis can be very useful, particularly if only small amounts of biological matrices are available. More data on analyzing new synthetic opioids (NSOs) in hair are needed to help interpretation in future cases. In this study, segmental single hair analysis is compared with segmental hair lock analysis to document an ocfentanil-related death. The hair lock and single hair analyses were performed using the LC-MS/MS method after decontamination and incubation. Ocfentanil (OcF) concentrations ranged from 42 to 150 pg/mg in the segmented hair lock, depending on the segments. The hair lock and single hair analyses showed similar results: the highest concentrations were measured in the first two centimeters and decreased from root to tip. The similar profiles obtained from both the lock of hair and the single hair demonstrate the relevance of single hair analysis in cases where very few data are available. This article describes OcF concentrations in an authentic hair sample after a documented intake of this molecule in a fatality.

Risk of ischaemic stroke associated with antiepileptic drugs: a population-based case-control study in Catalonia

BACKGROUND

Cerebrovascular disorders have occurred more frequently in some Central Nervous System (CNS) disorders, such as epilepsy. Some CNS drugs have been associated with increased stroke risk. Our aim was to estimate the risk of ischaemic stroke in patients exposed to antiepileptic drugs (AED).

METHODS

Population-based matched case-control study using SIDIAP database, based in electronic health records from primary healthcare from Catalonia, Spain. Cases were those patients with a registered diagnosis of first stroke during 2009-2014. Up to 10 controls were selected for each case and matched by sex, age, and geographic area and without a prior diagnosis of stroke. We considered global drug exposure to AED, past and current exposure and exposure in monotherapy to each AED.

RESULTS

2,865 cases and 19,406 controls were exposed to AED during the study period. Global exposure to levetiracetam [(OR_adj3.3, CI95 % 2.8-4.0)], phenytoin [OR_adj1.5, CI95 % 1.2-41.9)], and valproic acid [(OR_adj 1.3, CI95 % 1.1-1.6)], showed significantly association to ischaemic stroke that was also maintained with current exposure of levetiracetam [OR_adj4.1, CI95 % 3.3-5.2)] and valproic acid [OR_adj1.4, CI95 % 1.1-1.9)]. Current levetiracetam monotherapy showed a very high risk of ischaemic stroke [(OR_adj 5.1, CI95 % 3.7-6.9)].

CONCLUSIONS

Drugs used for other conditions than epilepsy (pregabalin, gabapentin) were the most used AED and both did not show a risk. Levetiracetam shows a risk for stroke even when assessed in current monotherapy. The lack of data regarding the link with diagnosis and severity in our study makes it necessary to conduct further studies to confirm or dismiss our results, focussing on levetiracetam.

Hemophagocytic Lymphohistiocytosis Occurring in Inflammatory Bowel Disease: Systematic Review

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a rare and aggressive syndrome of excessive cytokine requiring prompt recognition and aggressive therapy.

AIMS

We aimed to systematically characterize HLH in moderate-to-severe inflammatory bowel disease (IBD).

METHODS

We performed a systematic review of the literature (PubMED; EMBASE) and FDA Adverse Event Reporting System in accordance with the PRISMA statement. Use of biologics was used as a surrogate definition for disease severity (consistent with usual and contemporary clinical management), to enable identification of rare HLH cases with the highest fidelity.

RESULTS

58 cases of HLH occurring in IBD patients are known (mean age: 26.0 years, 70% male, 83% with Crohn's disease, mean disease duration 7.0 years). 34.5% of patients were undergoing induction therapy at HLH diagnosis. All cases occurred on patients exposed to anti-TNF agents, but cases with anti-integrin or anti-IL-12/23 exposure were reported. 2/3 of cases did not report prior AZA/6MP exposure. Underlying opportunistic infection or lymphoma was found in > 80% of cases. Survival was 70% if promptly recognized and treated. Five patients restarted biologics after HLH resolved, and one patient developed recurrent HLH.

CONCLUSIONS

HLH is rare among IBD patients exposed to biologic therapy. Most cases had an identifiable infection or malignancy at the time of diagnosis as well as history of immunomodulator use. Risk factors may include younger age, male gender, presence of Crohn's disease, and induction phase of treatment. Our study is not intended to assess risk of HLH with specific IBD therapies.

Maternal paracetamol intake and fetal ductus arteriosus constriction/closure: comprehensive signal evaluation using the Austin Bradford Hill criteria

PURPOSE

Acetaminophen (APAP) is available over-the-counter and widely regarded as safe for use in pregnancy. APAP has been used to close a persistently patent ductus arteriosus. Fetal constriction/closure of the ductus arteriosus (FCCDA), of public health interest given the drug's widespread use during pregnancy, is being monitored globally, including by the European Medicines Agency Pharmacovigilance Risk Assessment Committee. Our objective was to share a comprehensive signal evaluation of FCCDA with in utero APAP exposure to determine if the totality of evidence is sufficiently more consistent with one of the following two possibilities: (1) APAP never contributes to FCCDA (null hypothesis or H_O) versus (2) APAP may in some cases be at least a contributory cause of in utero DA narrowing (alternative hypothesis or H_A) to justify risk communication.

METHODS

To assess the relative support for H_O versus H_A, we synthesize and interpret within an Austin Bradford Hill criteria framework a comprehensive, cross-disciplinary set of published information and de novo analysis, including toxicology, epidemiology, clinical pharmacology, and clinical and quantitative pharmacovigilance analysis of spontaneous reports.

RESULTS

While residual uncertainty remains, the totality of information is more compatible with H_A than H₀, to the extent that it is reasonably possible that APAP may sometimes be at least a contributory cause of FCCDA.

CONCLUSION

It is reasonably possible that APAP may sometimes be at least a contributory cause of FCCDA, and this should therefore be communicated to stakeholders.

TRIAL REGISTRATION

CLINICALTRIALS.

GOV REGISTRATION

NOT APPLICABLE.

Does dose reduction of renally cleared antibiotics in patients with impaired renal function lead to adequate drug exposure? A systematic review

BACKGROUND

There is inconsistency between many guidelines in the recommended dose reduction of renally cleared antibiotics in patients with impaired renal function.

OBJECTIVES

This systematic review summarizes the available evidence on the adequacy of the recommended dose reduction in terms of achieving sufficient antibiotic drug exposure or pharmacokinetic/pharmacodynamic target attainment after treatment with these reduced doses.

DATA SOURCES

We systematically searched Ovid Medline and Embase from inception (respectively 1946 and 1947) through July 2019.

STUDY ELIGIBILITY CRITERIA

All studies reporting antibiotic drug exposure and/or pharmacokinetic/pharmacodynamic (PK/PD) target attainment after dose reduction of antibiotics in patients with impaired renal function.

PARTICIPANTS

Adult patients with or without infections.

INTERVENTIONS

Administration of reduced doses of antibiotics (orally, intravenously or intramuscularly).

METHODS

The reduced dose was considered adequate when the most relevant parameters of drug exposure or PK/PD target attainment in patients with impaired renal function were within a range of 80% to 125% of that patients with adequate renal function receiving a regular dose (reference) or when PK/PD target attainment was attained in at least 90% of the patients with impaired renal function, regardless of the lack of a reference group.

RESULTS

Twenty-seven of the 4202 identified studies were included. The quality of 15 of 27 studies was fair, and most studies were of β-lactams (12/27). Best evidence was available for meropenem: four studies were included, of which two studies were of good quality. Drug exposure for meropenem is 158% to 286% higher in patients with impaired renal function receiving reduced doses compared to patients with adequate renal function receiving regular doses. For all other antibiotics, a maximum of one good-quality study could be identified.

CONCLUSIONS

No good-quality evidence on the recommended dose reduction of renally cleared antibiotics in patients with impaired renal function is present, with the exception of meropenem.

Developmental and cardiac toxicities of propofol in zebrafish larvae

Propofol, a commonly used anesthetic, is convenient to use, induces quick effect, enables rapid recovery, and is widely accessible given its stable supply. However, its adverse effects are a concern. Reportedly, propofol exhibits a significant inhibitory effect on the respiratory and circulatory systems. Furthermore, intravenous administration of this drug results in hypotension, rapid heart rate, and respiratory failure. Because many pregnant women are administered propofol during childbirth, it may have a significant negative effect on the development of infants. Propofol can cause considerable developmental neurotoxicity and has known activity on the heart. However, the underling mechanisms of these toxicities remain unclear. In the present study, zebrafish embryos were exposed to propofol at different concentrations (0.05, 0.1, 0.5, 1, 5, 10, and 20 μg/ml) to determine its developmental and cardiac toxicities. Propofol exposure decreased the survival rate and hatchability of zebrafish embryos. Additionally, the embryo malformation rate increased in a concentration-dependent manner. Different types of malformations were observed following propofol administration. The proportion of pericardial cysts increased, whereas the heart rate and size decreased with an increase in propofol concentration. The quantitative reverse-transcription polymerase chain reaction revealed that propofol significantly altered the expression of genes related to cardiac development and functions in zebrafish. Collectively, our findings indicate that propofol exposure induces significant developmental and cardiac toxicities in zebrafish.

Machine learning on drug-specific data to predict small molecule teratogenicity

Pregnant women are an especially vulnerable population, given the sensitivity of a developing fetus to chemical exposures. However, prescribing behavior for the gravid patient is guided on limited human data and conflicting cases of adverse outcomes due to the exclusion of pregnant populations from randomized, controlled trials. These factors increase risk for adverse drug outcomes and reduce quality of care for pregnant populations. Herein, we propose the application of artificial intelligence to systematically predict the teratogenicity of a prescriptible small molecule from information inherent to the drug. Using unsupervised and supervised machine learning, our model probes all small molecules with known structure and teratogenicity data published in research-amenable formats to identify patterns among structural, meta-structural, and in vitro bioactivity data for each drug and its teratogenicity score. With this workflow, we discovered three chemical functionalities that predispose a drug towards increased teratogenicity and two moieties with potentially protective effects. Our models predict three clinically-relevant classes of teratogenicity with AUC = 0.8 and nearly double the predictive accuracy of a blind control for the same task, suggesting successful modeling. We also present extensive barriers to translational research that restrict data-driven studies in pregnancy and therapeutically "orphan" pregnant populations. Collectively, this work represents a first-in-kind platform for the application of computing to study and predict teratogenicity.

Discovery of indoximod prodrugs and characterization of clinical candidate NLG802

A series of different prodrugs of indoximod, including estesrs and peptide amides were synthesized with the aim of improving its oral bioavailability in humans. The pharmacokinetics of prodrugs that were stable in buffers, plasma and simulated gastric and intestinal fluids was first assessed in rats after oral dosing in solution or in capsule formulation. Two prodrugs that produced the highest exposure to indoximod in rats were further tested in Cynomolgus monkeys, a species in which indoximod has oral bioavailability of 6-10% and an equivalent dose-dependent exposure profile as humans. NLG802 was selected as the clinical development candidate after increasing oral bioavailability (>5-fold), C_max (6.1-3.6 fold) and AUC (2.9-5.2 fold) in monkeys, compared to equivalent molar oral doses of indoximod. NLG802 is extensively absorbed and rapidly metabolized to indoximod in all species tested and shows a safe toxicological profile at the anticipated therapeutic doses. NLG802 markedly enhanced the anti-tumor responses of tumor-specific pmel-1 T cells in a melanoma tumor model. In conclusion, NLG802 is a prodrug of indoximod expected to increase clinical drug exposure to indoximod above the current achievable levels, thus increasing the possibility of therapeutic effects in a larger fraction of the target patient population.

How to design a study to evaluate therapeutic drug monitoring in infectious diseases?

BACKGROUND

Therapeutic drug monitoring (TDM) is a tool to personalize and optimize dosing by measuring the drug concentration and subsequently adjusting the dose to reach a target concentration or exposure. The evidence to support TDM is however often ranked as expert opinion. Limitations in study design and sample size have hampered definitive conclusions of the potential added value of TDM.

OBJECTIVES

We aim to give expert opinion and discuss the main points and limitations of available data from antibiotic TDM trials and emphasize key elements for consideration in design of future clinical studies to quantify the benefits of TDM.

SOURCES

The sources were peer-reviewed publications, guidelines and expert opinions from the field of TDM.

CONTENT

This review focuses on key aspects of antimicrobial TDM study design: describing the rationale for a TDM study, assessing the exposure of a drug, assessing susceptibility of pathogens and selecting appropriate clinical endpoints. Moreover we provide guidance on appropriate study design.

IMPLICATIONS

This is an overview of different aspects relevant for the conduct of a TDM study. We believe that this paper will help researchers and clinicians to design and conduct high-quality TDM studies.

Methods in pharmacoepidemiology

Pharmacoepidemiology is the study of interactions between drugs and human populations, investigating, in real conditions of life, benefits, risks and use of drugs. Pharmacoepidemiology applies to drugs and their pharmacological evaluations, the different methods also used in epidemiology to assess in real conditions of life, benefits, risks and use of drugs. Pharmacoepidemiologic studies are ad-hoc studies or studies on databases. Specific methods exist to measure drug exposure, as well as indicators of compliance and misuse of drugs. Various designs for descriptive and explanatory studies exist, in a context in which a growing proportion of studies are carried out using medico-administrative data. The limits traditionally affecting the study designs are modified in this context, almost any design selected for the conduct of a study from these databases then deriving from a cohort in whom the information has been recorded prospectively and exhaustively.

Occult drug exposure in young children evaluated for physical abuse: An opportunity for intervention

BACKGROUND

Although screening for drug exposure is an important consideration in the evaluation of suspected child maltreatment, limited data are available on the frequency of drug exposure in children with suspected physical abuse.

OBJECTIVE

To examine occult drug and pharmaceutical exposure in young children with suspected physical abuse.

PARTICIPANTS AND SETTING

Children ages 2 weeks -59 months evaluated for physical abuse by a tertiary referral center Child Protection Team.

METHODS

Cross-sectional study of young children diagnosed with high, intermediate, or low concern for physical abuse and tested for occult drug exposure from 2013-2017. Chart review was performed to determine adherence to recommended testing and drug test results with comparison between groups.

RESULTS

Occult drug exposures were found in 5.1% (CI 3.6-7.8) of 453 children tested: 6.0% (CI 3.6-10.0) of 232 children with high concern for physical abuse, 5.0% (CI 2.7-9.3) of 179 children with intermediate concern, and 0% of 42 children with low concern. As adherence to protocol-based screening improved during the second half of the study, so did the overall rate of detection of occult drug exposures (7.9%, CI 5.2-11.9) in 252 children with intermediate or high concern for physical abuse. Most exposures were to cocaine, although non-prescribed pharmaceutical exposures were also detected.

CONCLUSIONS

Up to 7.9% of young children suspected of being physically abused also had an occult drug exposure. Given the adverse health consequences associated with exposure to a drug-endangered environment, screening for occult drug exposure should be considered in the evaluation of young children with intermediate or high concern for physical abuse.

Correlation between nivolumab exposure and treatment outcomes in non-small-cell lung cancer

INTRODUCTION

Nivolumab treatment is subject to large interpatient variability in both efficacy and toxicity, which may partly be explained by differences in nivolumab exposure. Exposure-response relationships in regular healthcare have not been extensively investigated for nivolumab. Therefore, we aimed to identify possible exposure-response relationships in nivolumab-treated patients with non-small-cell lung cancer (NSCLC).

METHODS

Patients with NSCLC who started second-line nivolumab therapy (3 mg/kg Q2W) between May 5th 2016 and August 1st 2017, and from whom serial blood samples, toxicity data and outcome data were prospectively collected, were included. Follow-up was carried out until November 1st 2017. Patients were classified according to the best overall response (BOR) based on the Response Evaluation Criteria in Solid Tumours, v1.1, and toxicities according to the Common Terminology Criteria for Adverse Events. Nivolumab trough concentrations were measured after 2, 4 and 10 weeks of treatment, excluding dose delays, and calculated geometric means were tested versus BOR or toxicity using analysis of variance and an independent samples t-test, respectively. Overall survival (OS) and progression-free survival were compared between high and low trough concentration groups.

RESULTS

Seventy-six patients were evaluable for analyses. Responders (n = 15) had higher mean trough concentrations than patients with progression (n = 33): 47% higher after 2 weeks (p = 0.001), 53% higher after 4 weeks (p = 0.008) and 73% higher after 10 weeks (p = 0.002). Higher trough concentrations were associated with longer OS (p = 0.001).

CONCLUSIONS

This study shows that patients with NSCLC with a response to nivolumab had a higher nivolumab exposure than patients with progression, indicating a potential exposure-response relationship. Further clinical research should focus on clarifying these exposure-response relationships.

Clinical Pharmacology and Pharmacometrics to Better Understand Physiological Changes During Pregnancy and Neonatal Life

Pregnant women, fetuses, and newborns are particularly vulnerable patient populations. During pregnancy, the body is subject to physiological changes that influence the pharmacokinetics and pharmacodynamics of drugs. Inappropriate dosing in pregnant women can result in sub-therapeutic or toxic effects, putting not only the pregnant woman but also her fetus at risk. During neonatal life, maturation processes also affect pharmacokinetics and pharmacodynamics of drugs. Inappropriate dosing in newborns leads not only to short-term complications but can also have a negative impact on the long-term development of infants and children. For these reasons, it is crucial to characterize physiological changes in pregnant women, describe placental transfer kinetics of drugs, and describe physiological changes related to the transition from intrauterine to extrauterine life and maturation processes in preterm and term neonates. Quantitative pharmacological approaches such as pharmacometric and physiologically-based modeling and model-based simulations can be useful to better understand and predict such physiological changes and their effects on drug exposure and response. This review article (1) gives an overview of physiological changes in pregnant women, their fetuses, and (pre)term neonates, (2) presents case studies to illustrate applications of new modeling and simulation approaches, and (3) discusses challenges and opportunities in optimizing and personalizing treatments during pregnancy and neonatal life.

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome in two young children: the importance of an early diagnosis

BACKGROUND

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a serious life-treating condition characterized by skin eruption, fever, haematologic abnormalities, and multi-organ involvement that can be fatal if unrecognized, especially in patients with liver failure. Diagnosis may be difficult because it is rarely described in children and can mimic many different conditions.

CASE PRESENTATION

We report two cases of DRESS syndrome due to prolonged antibiotic treatment in young children in whom recovery occurred following different therapeutic approaches. A previously healthy 5-year-old boy had been receiving intravenous vancomycin for right wrist and left elbow osteomyelitis and developed DRESS syndrome on day 30. The patient achieved a complete resolution of all symptoms with pulse methylprednisolone followed by oral prednisone. A 4-year-old girl with cystic fibrosis, pancreatic insufficiency, chronic pulmonary colonization by Gram-positive bacteria admitted for pulmonary exacerbation was treated with intravenous piperacillin-tazobactam and tobramycin. After 14 days of treatment, she developed DRESS syndrome: antibiotic treatment was therefore stopped, and without any further therapy, a progressive resolution of the patient's clinical features was observed within 7 days, while the normalization of laboratory abnormalities was achieved at 14 days.

CONCLUSIONS

Our cases highlight that paediatricians should be aware of the clinical presentations of and therapeutic approaches for DRESS syndrome, especially in children receiving long-term antibiotic treatment. The removal of the offending drug is crucial and may be the only life-saving measure. In more aggressive cases, corticosteroid or other immunosuppressive drugs should be considered to achieve the best outcome.

Drug exposure in early pregnancy might be related to the effects of increased maternal progesterone in implantation period

AIM

This short communication aims to evaluate the relation in between drug exposure time and early pregnancy regarding gestational weeks.

METHODS

The study covers the referrals made to the Department of Pharmacology for a teratogenic consultation in a 3-year period. From the recordings of pregnant women, the last menstrual period and the starting date of medication were used to determine the time of prescription with regard to gestational weeks.

RESULTS

In all of the three years, potentially teratogenic medication was prescribed more frequently in the 3rd, 4th and 5th gestational weeks (in between 15-35 days of pregnancy). Approximately 75% of the pregnant women in the study were prescribed with drugs, most frequently with analgesics, antibiotics, gastrointestinal drugs and antidepressants, in these gestational weeks.

CONCLUSIONS

The timing of prescriptions in early pregnancy frequently coincides with the increased levels of maternal progesterone in implantation period. Progesterone may lead to negative mood symptoms of an increased pain perception, anxiety, irritability and aggression in some of the pregnant women and therefore causes an increased stress condition which in turn may result in pain, infection and inflammation in the individual. Taking the frequently used medications into consideration, the reason for prescriptions in this period might be related to the symptoms originating from the effects of progesterone. Future studies are needed to better demonstrate this association of drug exposure and effects of maternal progesterone in early pregnancy.

Comparative clinical trial of the variability factors of the exposure indices used for the drug monitoring of two tacrolimus formulations in kidney transplant recipients

BACKGROUND

Several studies found differences in tacrolimus whole blood trough levels (C0) or area-under-the curve (AUC) between the twice-daily (Tac-BID) and once-daily (Tac-OD) formulations given to kidney transplant recipients at equal doses. As C0 is widely used as a surrogate of the AUC for individual dose adjustment, this study investigated the correlation and proportionality between C0 and the 24h-AUC, depending on the formulation, time post-transplantation, pharmacogenetics traits and other individual characteristics.

METHODS

45 adult kidney transplant recipients were randomized to receive either Tac OD or Tac BID. On days 8±1 (D8) and 90±3 (month 3, M3), blood samples were collected over 24h in both groups. Tacrolimus concentrations were determined using HPLC-MS/MS and common CYP3A5, CYP3A4 and ABCB1 genotypes characterized using allelic discrimination assays. Tacrolimus population pharmacokinetics was studied in the two patient groups using the Iterative Two Stage (ITS) technique, considering a one-compartment model with two gamma laws to describe the absorption phase. Bayesian estimation based on the C0, C1h and C3h concentrations was employed to estimate individual Tac AUC_0-12h and AUC_12-24h (for Tac BID), or AUC_0-24h (for Tac OD). Multiple linear regression was used to evaluate the influence of Tac formulation, post-transplantation period, recipient gender, existing glucose metabolism disorders, and CYP3A5, CYP3A4 and ABCB1 genotypes on C0, AUC_0-24h and the AUC-to-trough concentration ratios.

RESULTS

The Full Analysis Set comprised 22 patients on Tac OD and 20 on Tac BID. Tac exposure indices as well as their time evolution were similar in the two groups. Multi-linear modeling analysis showed that the Tac dose was higher with Tac-OD than Tac-BID, on D8 than at M3 and in CYP3A5 expressors (p<0.0001 for all). No such influence was found on C0 or C24h, while the AUC_0-24h was significantly higher on D8 than at M3. The AUC_0-24h/C0 ratio was not affected by the drug formulation and the polymorphisms studied, but it was significantly lower on D8 than at M3 (p=7.8×10^-5). In contrast, both the post-transplantation period (p=1.53×10^-4), and CYP3A5 expression (p=0.003) had a significant influence on the AUC_0-24h/C24h ratio, explaining 19% and 12% of its variability, respectively. Consistently, for both Tac formulations, the AUC_0-24h was better correlated with C24h than C0, and for Tac-BID the AUC_0-12h was better correlated with C12h than C0.

CONCLUSIONS

This study confirms that the precisely timed 12h- or 24h-post-dose blood concentration (as opposed to the vaguely defined 'trough level') is a convenient surrogate of the 24h-AUC of tacrolimus for the two TAC formulations over the first 3 months post-transplantation. Still, for a given C24h value, AUC_0-24h was higher on D8 and in CYP3A5 expressors. Bayesian estimation of AUC_0-12h for TAC BID and AUC_0-24h for TAC OD is feasible using only 3 time points within the first 3h, thus giving access to the actual overall exposure.

Antineoplastic drug residues inside homes of chemotherapy patients

Chemotherapy treatment of cancer patients has shifted from inpatient to outpatient administration. Thus, family members are potentially exposed to cytotoxic drug residues from patients' excretions inside their homes. The study's aim was to evaluate the surface contamination and the potential uptake of antineoplastic drug residues by family members at home of chemotherapy patients. Overall, 265 wipe samples from 13 homes were taken at two times after chemotherapy from different surfaces (toilet, bathroom, kitchen). 62 urine samples were collected from patients and family members on three days. Samples were analyzed for cyclophosphamide, 5-fluorouracil (urine: FBAL) and platinum (as marker for cis-, carbo- and oxaliplatin). Substantial contamination was found on every surface type (PT: 0.02-42.5pg/cm², 5-FU: ND-98.3pg/cm², CP: ND-283.3pg/cm²) with highest concentrations on toilet and bathroom surfaces. While patients' urinary drug concentrations often were elevated for more than 48h after administration, no drug residues were detectable in the family members' urine. This study provided an insight in the exposure situation against antineoplastic drug residues at home of chemotherapy patients. As contamination could be found on various surfaces adequate hygienic and protective measures are necessary to minimize the exposure risk for cohabitants.

Analytically Confirmed Intoxications Involving MDMB-CHMICA from the STRIDA Project

INTRODUCTION

About a decade ago, synthetic cannabinoids (SC) started to appear as recreational drugs on the new psychoactive substance (NPS) market. This report from the STRIDA project describes analytically confirmed intoxications involving MDMB-CHMICA (methyl-2-(1-(cyclohexylmethyl)-1H-indol-3-ylcarbonylamino)-3,3-dimethylbutanoate), a SC that was first detected in 2014.

STUDY DESIGN

This is an observational case series of patients from Sweden with suspected NPS exposure presenting in emergency departments and intensive care units. The results of retrospective serum and urine toxicological analysis were compared with clinical signs reported during consultation with the Poisons Information Centre and retrieved from medical records.

METHODS

Clinical and bioanalytical data in nine acute intoxications associated with MDMB-CHMICA during 2014-2015 are presented. The patients were aged 23-62 (median 34) years, and eight were men. MDMB-CHMICA (parent compound) was analytically confirmed in serum samples, using a liquid chromatography-high-resolution mass spectrometry multi-component method.

RESULTS

Of the nine MDMB-CHMICA-positive patients, eight had a Poisoning Severity Score (PSS) of 2 or 3, and five were monitored in the intensive care unit and all patients survived. Development of seizures and deep unconsciousness were common features. All cases except one also tested positive for other NPS and/or classical psychoactive compounds, hampering the possibility to establish a causal relationship between drug and toxic symptoms. MDMB-CHMICA was also identified in seven drug materials donated by the patients.

CONCLUSIONS

The association with severe adverse reactions in nine acute analytically confirmed intoxication cases involving MDMB-CHMICA is consistent with other reports of serious toxicity linked to this substance, suggesting that MDMB-CHMICA might be a particularly harmful SC.

Early ketamine exposure results in cardiac enlargement and heart dysfunction in Xenopus embryos

BACKGROUND

Ketamine is a commonly used clinical anesthetic and a popular recreational drug. However, with the exception of studies about the nervous system, studies about the effect of early ketamine exposure on embryos are rare. Xenopus laevis is a commonly used vertebrate model for assessing teratogenicity. Therefore, we treated Xenopus embryos with ketamine to evaluate its teratogenicity on embryos.

METHODS

Xenopus embryos were treated with ketamine from stages 8 to 21. Embryonic and cardiac morphology were analyzed using living embryo imaging and whole-mount RNA in situ hybridization (WMISH). Heart function was measured by heart rate and ventricular shortening fraction (VSF). The mRNA expression levels of several heart development-related genes were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The protein expression levels of XMLC2, phospho-histone H3 (pH3) and histone H3 were determined by western blot.

RESULTS

Ketamine caused concentration-dependent increases in mortality and shortening of body length. At a dose of 0.5 mg/ml, ketamine exposure resulted in cardiac enlargement as the primary manifestation of several malformations: gut defects, a curved axis and shortened body length. Cardiac cells underwent increased proliferation. Moreover, the heart rate and ventricular shortening fraction were decreased, findings indicative of heart dysfunction. XMLC2 expression levels were down-regulated at stages 28, 32/33, 35/36 and 46.

CONCLUSIONS

Ketamine exposure during early development has teratogenic effects on Xenopus embryos. The heart enlargement and decreased VSF may result from the down-regulation of XMLC2 mRNA and protein levels. These findings provide new insight into the potential fetal defects induced by ketamine exposure during early pregnancy.

Measuring drug exposure: concordance between defined daily dose and days' supply depended on drug class

OBJECTIVES

To determine the concordance between two methods to measure drug exposure duration from pharmacy claim data.

STUDY DESIGN AND SETTING

We conducted a cohort study using 2002-2007 US Medicaid data. Initiators of eight drug groups were identified: statins, metformin, atypical antipsychotics, warfarin, proton pump inhibitors (PPIs), angiotensin-converting enzyme (ACE) inhibitors, nonsteroidal anti-inflammatory drugs (ns-NSAIDs), and coxibs. For each patient, we calculated two measures of exposure duration using (1) observed days' supply available in US pharmacy claims and (2) the World Health Organisation's Defined Daily Dose (DDD) methodology. We used Wilcoxon signed rank tests to compare medians and Spearman correlations to assess correlation between the two measures.

RESULTS

Cohort sizes ranged from 143,885 warfarin users to >3,000,000 ns-NSAID users. Similar median exposure durations were observed for ACE inhibitors (70 days vs.75 days), PPIs (44 days vs. 45 days), and coxibs (44 days vs. 45 days). The DDD method overestimated exposure duration for ns-NSAIDs and underestimated for the remaining drug groups, relative to days' supply. Spearman correlation coefficients ranged from 0.2 to 0.8.

CONCLUSION

Using DDDs to estimate drug exposure duration can result in misclassification. The magnitude of this misclassification might depend on doses used which can vary according to factors such as local prescribing practices, renal function, and age.