Distinguishing Molecular Properties of OAT, OATP, and MRP Drug Substrates by Machine Learning.

The movement of organic anionic drugs across cell membranes is partly governed by interactions with SLC and ABC transporters in the intestine, liver, kidney, blood-brain barrier, placenta, breast, and other tissues. Major transporters involved include organic anion transporters (OATs, SLC22 family), organic anion transporting polypeptides (OATPs, SLCO family), and multidrug resistance proteins (MRPs, ABCC family). However, the sets of molecular properties of drugs that are necessary for interactions with OATs (OAT1, OAT3) vs. OATPs (OATP1B1, OATP1B3) vs. MRPs (MRP2, MRP4) are not well-understood. Defining these molecular properties is necessary for a better understanding of drug and metabolite handling across the gut-liver-kidney axis, gut-brain axis, and other multi-organ axes. It is also useful for tissue targeting of small molecule drugs and predicting drug-drug interactions and drug-metabolite interactions. Here, we curated a database of drugs shown to interact with these transporters in vitro and used chemoinformatic approaches to describe their molecular properties. We then sought to define sets of molecular properties that distinguish drugs interacting with OATs, OATPs, and MRPs in binary classifications using machine learning and artificial intelligence approaches. We identified sets of key molecular properties (e.g., rotatable bond count, lipophilicity, number of ringed structures) for classifying OATs vs. MRPs and OATs vs. OATPs. However, sets of molecular properties differentiating OATP vs. MRP substrates were less evident, as drugs interacting with MRP2 and MRP4 do not form a tight group owing to differing hydrophobicity and molecular complexity for interactions with the two transporters. If the results also hold for endogenous metabolites, they may deepen our knowledge of organ crosstalk, as described in the Remote Sensing and Signaling Theory. The results also provide a molecular basis for understanding how small organic molecules differentially interact with OATs, OATPs, and MRPs.

A multicenter, randomized, double-blind, placebo-controlled ascending dose study to evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamic (PD) effects of Posiphen in subjects with Early Alzheimer's Disease.

Background: Amyloid beta protein (Aß) is a treatment target in Alzheimer's Disease (AD). Lowering production of its parent protein, APP, has benefits in preclinical models. Posiphen binds to an iron-responsive element in APP mRNA and decreases translation of APP and Aß. To augment human data for Posiphen, we evaluated safety, tolerability and pharmacokinetic and pharmacodynamic (PD) effects on Aß metabolism using Stable Isotope Labeling Kinetic (SILK) analysis. Methods: Double-blind phase 1b randomized ascending dose clinical trial, at five sites, under an IRB-approved protocol. Participants with mild cognitive impairment or mild AD (Early AD) with positive CSF biomarkers were randomized (within each dose arm) to Posiphen or placebo. Pretreatment assessment included lumbar puncture for CSF. Participants took Posiphen or placebo for 21-23 days, then underwent CSF catheter placement, intravenous infusion of 13C6-leucine, and CSF sampling for 36 hours. Safety and tolerability were assessed through participant reports, EKG and laboratory tests. CSF SILK analysis measured Aß40, 38 and 42 with immunoprecipitation-mass spectrometry. Baseline and day 21 CSF APP, Aß and other biomarkers were measured with immunoassays. The Mini-Mental State Exam and ADAS-cog12 were given at baseline and day 21. Results: From June 2017 to December 2021, 19 participants were enrolled, in dose cohorts (6 active: 2 placebo) of 60 mg once/day and 60 mg twice/day; 1 participant was enrolled and completed 60 mg three times/day. 10 active drug and 5 placebo participants completed all study procedures. Posiphen was safe and well-tolerated. 8 participants had headaches related to CSF catheterization; 5 needed blood patches. Prespecified SILK analyses of Fractional Synthesis Rate (FSR) for CSF Aß40 showed no significant overall or dose-dependent effects of Posiphen vs. placebo. Comprehensive multiparameter modeling of APP kinetics supported dose-dependent lowering of APP production by Posiphen. Cognitive measures and CSF biomarkers did not change significantly from baseline to 21 days in Posiphen vs placebo groups. Conclusions: Posiphen was safe and well-tolerated in Early AD. A multicenter SILK study was feasible. Findings are limited by small sample size but provide additional supportive safety and PK data. Comprehensive modeling of biomarker dynamics using SILK data may reveal subtle drug effects. Trial registration: NCT02925650 on clinicaltrials.gov.

Pharmacokinetics, Fecal Output, and Grimace Scores in Rabbits Given Long-acting Buprenorphine or Fentanyl for Postsurgical Analgesia.

The New Zealand white rabbit (Oryctolagus cuniculus) is a frequently used surgical model. Pain management after surgery is a critical aspect of animal welfare. Recently, a long-acting buprenorphine formulation (Ethiqa XR; EXR) was approved for use in rats and mice but has not yet been investigated in rabbits. The current study aimed to determine whether a single subcutaneous dose of 0.15 mg/kg of EXR could achieve and maintain therapeutic buprenorphine plasma concentrations (0.1 ng/mL) for 72 h in male and female rabbits. We also evaluated the safety profiles of EXR and the fentanyl patch (FP) by assessing fecal output after surgery, because opioids are known to decrease intestinal motility. Behavior and pain scores were compared for rabbits that received either EXR or the FP after undergoing an annulus puncture procedure to induce osteoarthritis. EXR at 0.15 mg/kg SC provided a shorter time to onset and sustained analgesia for 72 h in male and female rabbits, whereas the FP provided suboptimal analgesia after 48 h. Both EXR and FP reduced fecal output after surgery. Output returned to baseline levels within 72 h for the EXR group and remained slightly below baseline at 96 h after surgery for the fentanyl group. Grimace pain scores revealed no significant difference between treatment groups. These results suggest that EXR is a safe and effective option for postoperative pain management in rabbits.

Concentrations of remdesivir and GS-441524 in human milk from lactating individuals diagnosed with COVID-19.

IMPACT: Findings from this study provide further reassuring evidence that infant exposure through human milk received from lactating individuals who require treatment with remdesivir is negligible.

A single post-exposure oxime RS194B treatment rapidly reactivates acetylcholinesterase and reverses acute symptoms in macaques exposed to diethylphosphorothioate parathion and chlorpyrifos insecticides.

Millions of individuals globally suffer from inadvertent, occupational or self-harm exposures from organophosphate (OP) insecticides, significantly impacting human health. Similar to nerve agents, insecticides are neurotoxins that target and inhibit acetylcholinesterase (AChE) in central and peripheral synapses in the cholinergic nervous system. Post-exposure therapeutic countermeasures generally include administration of atropine with an oxime to reactivate the OP-inhibited AChE. However, animal model studies and recent clinical trials using insecticide-poisoned individuals have shown minimal clinical benefits of the currently approved oximes and their efficacy as antidotes has been debated. Currently used oximes either reactivate poorly, do not readily cross the blood-brain barrier (BBB), or are rapidly cleared from the circulation and must be repeatedly administered. Zwitterionic oximes of unbranched and simplified structure, for example RS194B, have been developed that efficiently cross the BBB resulting in reactivation of OP-inhibited AChE and dramatic reversal of severe clinical symptoms in mice and macaques exposed to OP insecticides or nerve agents. Thus, a single IM injection of RS194B has been shown to rapidly restore blood AChE and butyrylcholinesterase (BChE) activity, reverse cholinergic symptoms, and prevent death in macaques following lethal inhaled sarin and paraoxon exposure. The present macaque studies extend these findings and assess the ability of post-exposure RS194B treatment to counteract oral poisoning by highly toxic diethylphosphorothioate insecticides such as parathion and chlorpyrifos. These OPs require conversion by P450 in the liver of the inactive thions to the active toxic oxon forms, and once again demonstrated RS194B efficacy to reactivate and alleviate clinical symptoms within 60 mins of a single IM administration. Furthermore, when delivered orally, the Tmax of RS194B at 1-2 h was in the same range as those administered IM but were maintained in the circulation for longer periods greatly facilitating the use of RS194B as a non-invasive treatment, especially in isolated rural settings.

Brief Report: Dolutegravir Plasma Protein Binding and Unbound Concentrations During Pregnancy and Postpartum.

BACKGROUND: Clinical interpretation of the reduced dolutegravir (DTG) plasma concentrations reported during pregnancy is complicated by its high plasma protein binding. Plasma proteins significantly decrease during pregnancy, and understanding changes in DTG protein binding and its therapeutically active unbound concentrations are necessary to evaluate the impact of pregnancy changes on DTG pharmacokinetics. METHODS: Retrospective assessment of plasma samples from pregnant women living with HIV enrolled in the International Maternal Pediatric Adolescent AIDS Clinical Trials Network P1026s study receiving 50 mg DTG film-coated tablets once daily as part of clinical care. Unbound and total DTG concentrations were determined predose (C0) and at maximum (Cmax) concentrations during the second trimester (2T), third trimester (3T), and postpartum (PP). Percentage unbound was calculated as the ratio of ultrafiltrate unbound DTG concentration to total DTG concentration. RESULTS: Twenty-nine mothers were included for protein binding evaluations; 15, 27, and 23 from the 2T, 3T, and PP, respectively. DTG % unbound for C0 and Cmax were significantly different by stage of pregnancy, with 3T significantly higher compared with PP; 1.02% vs. 0.69% (P = 0.0067) for C0 and 0.76% vs. 0.46% for Cmax (P = 0.0056). Median (IQR) unbound concentrations for C0 were 6.3 (4.7-18.4) for the 2T, 8.0 (5.6-16.9) for the 3T, and 13.3 (8.4-22.7) ng/mL PP, significantly different between 2T and PP (P = 0.0039), but not different between 3T and PP (P = 0.46). CONCLUSION: Lower total DTG plasma concentrations during pregnancy coincide with temporal decreases in DTG protein binding, resulting in comparable unbound DTG concentrations during the 3T and PP.

Directed evolution unlocks oxygen reactivity for a nicotine-degrading flavoenzyme.

The flavoenzyme nicotine oxidoreductase (NicA2) is a promising injectable treatment to aid in the cessation of smoking, a behavior responsible for one in ten deaths worldwide. NicA2 acts by degrading nicotine in the bloodstream before it reaches the brain. Clinical use of NicA2 is limited by its poor catalytic activity in the absence of its natural electron acceptor CycN. Without CycN, NicA2 is instead oxidized slowly by dioxygen (O2), necessitating unfeasibly large doses in a therapeutic setting. Here, we report a genetic selection strategy that directly links CycN-independent activity of NicA2 to growth of Pseudomonas putida S16. This selection enabled us to evolve NicA2 variants with substantial improvement in their rate of oxidation by O2. The encoded mutations cluster around a putative O2 tunnel, increasing flexibility and accessibility to O2 in this region. These mutations further confer desirable clinical properties. A variant form of NicA2 is tenfold more effective than the wild type at degrading nicotine in the bloodstream of rats.

Cannabidiol Exposure Through Maternal Marijuana Use: Predictions in Breastfed Infants.

BACKGROUND AND OBJECTIVE: Knowledge about exposure to cannabidiol (CBD) in breastfed infants can provide an improved understanding of potential risk. The aim was to predict CBD exposure in breastfed infants from mothers taking CBD and CBD-containing products. METHODS: Cannabidiol concentrations in milk previously attained from data collected through an existing human milk research biorepository were used to simulate infant doses and identify subgroups. A developed pediatric physiologically based pharmacokinetic model produced virtual breastfed infants administered the simulated CBD doses. Predicted breastfed infant exposures and upper area under the curve ratios were compared to the lowest therapeutic dose for approved indications in children. RESULTS: The existing human milk research biorepository contained 200 samples from 181 unique breastfeeding mothers for whom self-reported administration data and CBD concentrations had previously been measured. Samples that were above the lower limit of quantification with only one maternal administration type revealed that administration type, i.e., joint/blunt or edible versus oil or pipe, resulted in significantly different subgroups in terms of milk concentrations. Resulting simulated infant doses (ng/kg) were described by lognormal distributions with geometric means and geometric standard deviations: 0.61 ± 2.41 all concentrations, 0.10 ± 0.37 joint/blunt or edible, and 2.23 ± 8.15 oil or pipe. Doses administered to breastfed infants had exposures magnitudes lower than exposures in children aged 4-11 years administered the lowest therapeutic dose for approved indications, and low upper area under the curve ratios. CONCLUSIONS: Based on real-world use, breastfeeding infants are predicted to receive very small exposures of CBD through milk. Studies examining adverse reactions will provide further insight into potential risk.

Evaluation of bumetanide as a potential therapeutic agent for Alzheimer's disease.

Therapeutics discovery and development for Alzheimer's disease (AD) has been an area of intense research to alleviate memory loss and the underlying pathogenic processes. Recent drug discovery approaches have utilized in silico computational strategies for drug candidate selection which has opened the door to repurposing drugs for AD. Computational analysis of gene expression signatures of patients stratified by the APOE4 risk allele of AD led to the discovery of the FDA-approved drug bumetanide as a top candidate agent that reverses APOE4 transcriptomic brain signatures and improves memory deficits in APOE4 animal models of AD. Bumetanide is a loop diuretic which inhibits the kidney Na+-K+-2Cl- cotransporter isoform, NKCC2, for the treatment of hypertension and edema in cardiovascular, liver, and renal disease. Electronic health record data revealed that patients exposed to bumetanide have lower incidences of AD by 35%-70%. In the brain, bumetanide has been proposed to antagonize the NKCC1 isoform which mediates cellular uptake of chloride ions. Blocking neuronal NKCC1 leads to a decrease in intracellular chloride and thus promotes GABAergic receptor mediated hyperpolarization, which may ameliorate disease conditions associated with GABAergic-mediated depolarization. NKCC1 is expressed in neurons and in all brain cells including glia (oligodendrocytes, microglia, and astrocytes) and the vasculature. In consideration of bumetanide as a repurposed drug for AD, this review evaluates its pharmaceutical properties with respect to its estimated brain levels across doses that can improve neurologic disease deficits of animal models to distinguish between NKCC1 and non-NKCC1 mechanisms. The available data indicate that bumetanide efficacy may occur at brain drug levels that are below those required for inhibition of the NKCC1 transporter which implicates non-NKCC1 brain mechansims for improvement of brain dysfunctions and memory deficits. Alternatively, peripheral bumetanide mechanisms may involve cells outside the central nervous system (e.g., in epithelia and the immune system). Clinical bumetanide doses for improved neurological deficits are reviewed. Regardless of mechanism, the efficacy of bumetanide to improve memory deficits in the APOE4 model of AD and its potential to reduce the incidence of AD provide support for clinical investigation of bumetanide as a repurposed AD therapeutic agent.

Severe arsenic poisoning due to Ayurvedic supplements.

Patients that are taking Ayurvedic supplements have an increased risk of heavy metal toxicity. Lead, arsenic, and mercury are frequently identified in these supplements and can cause clinically significant toxicity. Clinicians should screen patients routinely for use of non-pharmaceutical medications and supplements.

Translating Clinical Pharmacology Data in Pregnancy to Evidence-Based Guideline Recommendations: Perspectives From the HIV Field.

Pharmacokinetic (PK) studies in pregnant, postpartum, and breastfeeding people are critical to informing appropriate medication use and dosing. A key component of translating PK results in these complex populations into clinical practice involves the systematic review and interpretation of data by guideline panels, composed of clinicians, scientists, and community members, to leverage available data for informed decision making by clinicians and patients and offer clinical best practices. Interpretation of PK data in pregnancy involves evaluation of multiple factors such as the study design, target population, and type of sampling performed. Assessments of fetal and infant drug exposure while in utero or during breastfeeding, respectively, are also critical for informing whether medications are safe to use during pregnancy and throughout postpartum in lactating people. This review will provide an overview of this translational process, discussion of the various factors considered by guideline panels, and practical aspects of implementing certain recommendations, using the HIV field as an example.

Variable Delta-9-Tetrahydrocannabinol Pharmacokinetics and Pharmacodynamics After Cannabis Smoking in Regular Users.

BACKGROUND: Despite its federally restricted status, cannabis is widely used medicinally and recreationally. The pharmacokinetics (PK) and central nervous system (CNS) effects of tetrahydrocannabinol (THC), the major psychoactive cannabinoid, are not well understood. The objective of this study was to develop a population PK model of inhaled THC, including sources of variability, and to conduct an exploratory analysis of potential exposure-response relationships. METHODS: Regular adult cannabis users smoked a single cannabis cigarette containing 5.9% THC (Chemovar A) or 13.4% THC (Chemovar B) ad libitum. THC concentrations in whole blood were measured and used to develop a population PK model to identify potential factors contributing to interindividual variability in THC PK and to describe THC disposition. Relationships between model-predicted exposure and heart rate, change in composite driving score on a driving simulator, and perceived highness were evaluated. RESULTS: From the 102 participants, a total of 770 blood THC concentrations were obtained. A two-compartment structural model adequately fit the data. Chemovar and baseline THC (THC BL ) were found to be significant covariates for bioavailability, with Chemovar A having better THC absorption. The model predicted that heavy users-those with the highest THC BL -would have significantly higher absorption than those with lighter previous use. There was a statistically significant relationship between exposure and heart rate, and exposure and perceived highness. CONCLUSIONS: THC PK is highly variable and related to baseline THC concentrations and different chemovars. The developed population PK model showed that heavier users had higher THC bioavailability. To better understand the factors affecting THC PK and dose-response relationships, future studies should incorporate a wide range of doses, multiple routes of administration, and different formulations relevant to typical community use.

Identification of structurally diverse FSP1 inhibitors that sensitize cancer cells to ferroptosis.

Ferroptosis is a regulated form of cell death associated with the iron-dependent accumulation of phospholipid hydroperoxides. Inducing ferroptosis is a promising approach to treat therapy-resistant cancer. Ferroptosis suppressor protein 1 (FSP1) promotes ferroptosis resistance in cancer by generating the antioxidant form of coenzyme Q10 (CoQ). Despite the important role of FSP1, few molecular tools exist that target the CoQ-FSP1 pathway. Through a series of chemical screens, we identify several structurally diverse FSP1 inhibitors. The most potent of these compounds, ferroptosis sensitizer 1 (FSEN1), is an uncompetitive inhibitor that acts selectively through on-target inhibition of FSP1 to sensitize cancer cells to ferroptosis. Furthermore, a synthetic lethality screen reveals that FSEN1 synergizes with endoperoxide-containing ferroptosis inducers, including dihydroartemisinin, to trigger ferroptosis. These results provide new tools that catalyze the exploration of FSP1 as a therapeutic target and highlight the value of combinatorial therapeutic regimes targeting FSP1 and additional ferroptosis defense pathways.

Comparative Pharmacokinetics and Injection Site Histopathology in Nude Mice Treated with Long-acting Buprenorphine Formulations.

Two long-acting formulations of buprenorphine are commercially available as analgesics for rodents. However, these drugs have not yet been studied in nude mice. We sought to investigate whether the manufacturer-recommended or labeled mouse doses of either drug would provide and sustain the purported therapeutic plasma concentration of buprenorphine (1 ng/mL) over 72 h in nude mice and to characterize the injection site histopathology. NU/NU nude and NU/+ heterozygous mice were subcutaneously injected with extended-release buprenorphine polymeric formulation (ER; 1 mg/kg), extendedrelease buprenorphine suspension (XR; 3.25 mg/kg), or saline (2.5 mL/kg). Plasma concentrations of buprenorphine were measured 6, 24, 48, and 72 h after injection. The injection site was examined histologically at 96 h after administration. XR dosing yielded significantly higher plasma buprenorphine concentrations than did ER dosing at every time point in both nude and heterozygous mice. No significant difference in plasma buprenorphine concentrations were detected between nude and heterozygous mice. Both formulations yielded plasma levels of buprenorphine of over 1 ng/mL at 6 h; XR sustained buprenorphine plasma levels above 1 ng/mL for over 48 h, whereas ER sustained this level for over 6 h. Injections sites of both formulations were characterized by a cystic lesion with a fibrous/fibroblastic capsule. ER induced more inflammatory infiltrates than did XR. This study indicates that while both XR and ER are suitable for use in nude mice, XR has a longer duration of likely therapeutic plasma levels and induces less subcutaneous inflammation at the injection site.

Development of Potent and Highly Selective Epoxyketone-Based Plasmodium Proteasome Inhibitors.

Here, we present remarkable epoxyketone-based proteasome inhibitors with low nanomolar in vitro potency for blood-stage Plasmodium falciparum and low cytotoxicity for human cells. Our best compound has more than 2,000-fold greater selectivity for erythrocytic-stage P. falciparum over HepG2 and H460 cells, which is largely driven by the accommodation of the parasite proteasome for a D-amino acid in the P3 position and the preference for a difluorobenzyl group in the P1 position. We isolated the proteasome from P. falciparum cell extracts and determined that the best compound is 171-fold more potent at inhibiting the ß5 subunit of P. falciparum proteasome when compared to the same subunit of the human constitutive proteasome. These compounds also significantly reduce parasitemia in a P. berghei mouse infection model and prolong survival of animals by an average of 6 days. The current epoxyketone inhibitors are ideal starting compounds for orally bioavailable anti-malarial drugs.

Physiologically-based pharmacokinetic modeling of remdesivir and its metabolites in pregnant women with COVID-19.

Pregnant individuals are at high risk for severe illness from COVID-19, and there is an urgent need to identify safe and effective therapeutics for this population. Remdesivir (RDV) is a SARS-CoV-2 nucleotide analog RNA polymerase inhibitor. Limited RDV pharmacokinetic (PK) and safety data are available for pregnant women receiving RDV. The aims of this study were to translate a previously published nonpregnant adult physiologically based PK (PBPK) model for RDV to pregnancy and evaluate model performance with emerging clinical PK data in pregnant women with COVID-19. The pregnancy model was built in the Open Systems Pharmacology software suite (Version 10) including PK-Sim® and MoBi® with pregnancy-related changes of relevant enzymes applied. PK were predicted in a virtual population of 1000 pregnant subjects, and prediction results were compared with in vivo PK data from the International Maternal, Pediatric, Adolescent AIDS Clinical Trials (IMPAACT) Network  2032 study. The developed PBPK model successfully captured RDV and its metabolites' plasma concentrations during pregnancy. The ratios of prediction versus observation for RDV area under the curve from time 0 to infinity (AUC0-∞ ) and maximum concentration (Cmax ) were 1.61 and 1.17, respectively. For GS-704277, the ratios of predicted versus observed were 0.94 for AUC0-∞ and 1.20 for Cmax . For GS-441524, the ratios of predicted versus observed were 1.03 for AUC0-24 , 1.05 for Cmax , and 1.07 for concentrations at 24 h. All predictions of AUC and Cmax for RDV and its metabolites were within a twofold error range, and about 60% of predictions were within a 10% error range. These findings demonstrate the feasibility of translating PBPK models to pregnant women to potentially guide trial design, clinical decision making, and drug development.

Transfer of antibiotics and their metabolites in human milk: Implications for infant health and microbiota.

Antibiotics are an essential tool for perinatal care. While antibiotics can play a life-saving role for both parents and infants, they also cause collateral damage to the beneficial bacteria that make up the host gut microbiota. This is especially true for infants, whose developing gut microbiota is uniquely sensitive to antibiotic perturbation. Emerging evidence suggests that disruption of these bacterial populations during this crucial developmental window can have long-term effects on infant health and development. Although most current studies have focused on microbial disruptions caused by direct antibiotic administration to infants or prenatal exposure to antibiotics administered to the mother, little is known about whether antibiotics in human milk may pose similar risks to the infant. This review surveys current data on antibiotic transfer during lactation and highlights new methodologies to assess drug transfer in human milk. Finally, we provide recommendations for future work to ensure antibiotic use in lactating parents is safe and effective for both parents and infants.

Estimation of Kidney Function in Patients With Multiple Myeloma: Implications for Lenalidomide Dosing.

BACKGROUND: Lenalidomide is an immunomodulatory drug used to treat multiple myeloma that requires renal dosing adjustment based on Cockcroft-Gault (CG). Various equations to estimate kidney function exist and pose a potential issue with lenalidomide dosing. OBJECTIVE: The objective of this analysis was to evaluate the impact of estimating kidney function in newly diagnosed multiple myeloma patients with CG, Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and their potential impact on lenalidomide dosing. METHODS: Data from 1121 multiple myeloma patients at the time of diagnosis acquired from the Mayo Clinic were used to calculate creatinine clearance (CrCl) using Cockcroft-Gault with actual body weight (CGABW), ideal body weight (CGIBW), or adjusted body weight (CGAdjBW); MDRD; and CKD-EPI for each subject. Discordances in dosing were then analyzed, and lenalidomide exposure was calculated for each subject to assess impact on pharmacokinetics of lenalidomide for patients who received discordant doses. RESULTS: Overall, approximately 16% of patients received a discordant dose when using MDRD or CKD-EPI instead of CGABW. The most common dose discordance was the decrease of a full dose of lenalidomide 25 mg when using CGABW down to 10 mg and when using MDRD or CKD-EPI with 53.8% to 55.6% of all discordances in this category. When assessing different body weights, the most common discordance was a decrease from 25 to 10 mg when using CGIBW instead of CGABW; the same trend was observed when using CGAdjBW instead as well. Patients were also at risk of over- or underexposure based on area under the concentration versus time curve (AUC) for discordant dosing. CONCLUSION AND RELEVANCE: A significant proportion of patients are at risk of under- or overdose of lenalidomide if CKD-EPI or MDRD are used instead of CGABW. Physicians should use CGABW when estimating renal function to dose lenalidomide.

Non-invasive skin sampling detects systemically administered drugs in humans.

Clinical testing typically relies on invasive blood draws and biopsies. Alternative methods of sample collection are continually being developed to improve patient experience; swabbing the skin is one of the least invasive sampling methods possible. To show that skin swabs in combination with untargeted mass spectrometry (metabolomics) can be used for non-invasive monitoring of an oral drug, we report the kinetics and metabolism of diphenhydramine in healthy volunteers (n = 10) over the course of 24 hours in blood and three regions of the skin. Diphenhydramine and its metabolites were observed on the skin after peak plasma levels, varying by compound and skin location, and is an illustrative example of how systemically administered molecules can be detected on the skin surface. The observation of diphenhydramine directly from the skin supports the hypothesis that both parent drug and metabolites can be qualitatively measured from a simple non-invasive swab of the skin surface. The mechanism of the drug and metabolites pathway to the skin's surface remains unknown.

Pediatric and Adult Placebo Response Rates in Placebo-Controlled Clinical Trials Submitted to the US Food and Drug Administration 2012-2020.

The use of placebo concurrent control (placebo-controlled) is the most rigorous method of evaluating the safety and efficacy of investigational treatments. However, the use of a placebo group in pediatric product development can be challenging due to ethical considerations and potential differences in placebo response rates between adults and children. This study reports the US Food and Drug Administration's experience with placebo response rates in the pediatric population. Products studied under the Best Pharmaceuticals for Children Act and the Pediatric Research Equity Act between 2012 and 2020 were screened. Study characteristics including study type, primary efficacy endpoint(s), placebo response rates for the primary efficacy endpoint(s) and studied age range were collected. A total of 71 drug products used a placebo-controlled trial. Of these, thirteen products had an identical study design and trial characteristics including the primary efficacy endpoints between pediatric and adult studies. Fifteen products were studied in trials with identical study design but only different primary efficacy endpoints in pediatric and adult populations. Ten products had combined adolescent and adult trials with separate pediatric trials in younger age groups. In each of these cases, the pediatric placebo response was greater, for some trials, and less, for other trials, than the adult placebo response. The pediatric placebo response can vary within an age group for a drug product. Future studies should examine the factors leading to a similarity or dissimilarity in placebo response between pediatric patients and adults.