It is well-accepted that off-label drug dosing recommendations for pediatric patients should be based on the best available evidence. However, the available traditional evidence is often low. To bridge this gap, physiologically-based pharmacokinetic (PBPK) modeling is a scientifically well-founded tool that can be used to enable model-informed dosing (MID) recommendations in children in clinical practice. In this tutorial, we provide a pragmatic, PBPK-based pediatric modeling workflow. For this approach to be successfully implemented in pediatric clinical practice, a thorough understanding of the model assumptions and limitations is required. More importantly, careful evaluation of an MID approach within the context of overall benefits and the potential risks is crucial. The tutorial is aimed to help modelers, researchers, and clinicians, to effectively use PBPK simulations to support pediatric drug dosing.

Based on recent guidance and publicly available approvals, the US Food and Drug Administration (FDA) has demonstrated its openness to considering evidence of effectiveness from real-world data (RWD) and nonrandomized studies (or "real-world evidence (RWE)") in its decision making. Through analysis of the FDA approvals, several authors have identified methodologic issues commonly discussed by FDA reviewers. However, in our analysis of FDA guidance and use cases, acceptability of RWE also critically depends on whether the characteristics of the clinical development program align with circumstances in which the FDA may have flexibility in considering evidence from real-world study designs relative to more robust designs. Successful use of RWD requires advance planning to allocate the necessary resources and time to undertake principled epidemiology approaches to study design, data selection, and implementation of analyses as well as address regulatory feedback. Thus, sponsors benefit from early identification of programs in which successful RWD use is more likely, to ensure efficient use of resources required for the next steps of scientific feasibility assessment. We developed SURF, a screening tool intended to help a sponsor decide whether to prioritize resources for further exploring the feasibility of using an RWD approach to meet the FDA's effectiveness evidentiary standards for a particular clinical development program. Here, we provide an analysis of FDA guidance, highlighting the circumstances in which RWD approaches may be most acceptable, and demonstrate the use of this screening tool, including the rationale for its construction, types of evidence needed, and application to publicly available approvals as support of concept.

Gabapentin is prescribed for pain and is perceived as safe generally. However, gabapentin can cause respiratory depression, exacerbated by concomitant central nervous system depressants (e.g., opioids), a concern for vulnerable populations. We compared mortality rates among new users of either gabapentin or duloxetine with or without concurrent opioids in the 20% Medicare sample. We conducted a new-user design retrospective cohort study, in Medicare enrollees ages 65-89 years with noncancer chronic pain and no severe illness who filled prescriptions between 2015 and 2018 for gabapentin (n = 233,060) or duloxetine (n = 34,009). Daily opioid doses, estimated in morphine milligram equivalents (MMEs), were classified into none, low (0 < MME < 50), and high (≥ 50 MME), based on Centers for Disease Control and Prevention (CDC) recommendations. The outcomes were all-cause mortality (primary) and out-of-hospital mortality (secondary). We used inverse probability of treatment weighting to adjust for differences between gabapentin and duloxetine users. During 116,707 person-years of follow-up, 1,379 patients died. All-cause mortality rate in gabapentin users was 12.16 per 1,000 person-years vs. 9.94 per 1,000 in duloxetine users. Risks were similar for users with no concurrent opioids (adjusted hazard ratio (aHR) = 1.03, 95% confidence interval (CI): 0.80-1.31) or low-dose daily opioids (aHR = 1.06, 95% CI: 0.63-1.76). However, gabapentin users receiving concurrent high-dose daily opioids had an increased rate of all-cause mortality compared with duloxetine users on high-dose opioids (aHR = 2.03, 95% CI: 1.19-3.46). Out-of-hospital mortality yielded similar results. In this retrospective cohort study of Medicare beneficiaries, concurrent use of high-dose opioids and gabapentin was associated with a higher all-cause mortality risk than that for concurrent use of high-dose opioids and duloxetine.

The US Food and Drug Administration (FDA) is evaluating the potential use of real-world evidence (RWE) in regulatory decision making. Some groups have evaluated the use of RWE in regulatory submissions in the United States and abroad, reporting that reliance on RWE to support new product approvals is relatively common. Confusion regarding the use of RWE in drug-approval decisions may arise, however, based on different application of the terms real-world data (RWD) and RWE. We evaluated RWE in new drug applications (NDAs) and biologics license applications (BLAs) from January 2019 to June 2021 for novel drugs and biologics approved by the FDA with indications related to psychiatry, neurology, pain, or sedation (here, termed neuroscience-related). We sought to determine whether the submissions included RWE and to describe the types of data and study designs used. Thirty neuroscience-related NDAs or BLAs were identified for novel drugs and biologics approved during the time-period of interest. Among these approvals, three applications (10%) were adjudicated as containing RWE, one of which included RWE as primary evidence of effectiveness. Our findings highlight how different operational definitions of the terms RWD and RWE can result in demonstrably different reporting of the use of RWE in regulatory decision making for neuroscience-related novel drugs and biologics. A better understanding of this topic, along with awareness of regulatory definitions of RWE, are important factors to promote accurate tracking and reporting of regulatory submissions involving RWE. These factors can also improve awareness among the stakeholder community regarding the role of RWD and RWE in regulatory decision making.

In the maintenance phase of Associazione Italiana di Ematologia e Oncologia Pediatrica (AIEOP)- Berlin-Frankfurt-Muenster (BFM) acute lymphoblastic leukemia (ALL) 2009 protocol, mercaptopurine (MP) is given at the planned dose of 50 mg/m2 /day; however, dose adjustments are routinely performed to target patients' white blood cells to the optimal range of 2,000-3,000 cells/μL. Pediatric patients with ALL (n = 290, age: median (1st-3rd quartile): 4.8 (3.0-8.1) years; boys: 56.9%) were enrolled mainly in 4 medium-large Italian pediatric hospitals; 14.1% of patients relapsed after a median (1st-3rd quartile) follow-up time of 4.43 (3.82-5.46) years from maintenance beginning. MP metabolites (thionucleotide (TGN) and methyl-derivatives (MMPN)) were measured in the erythrocytes of 387 blood samples of 200 patients by high performance liquid chromatography with ultraviolet detection. Single-nucleotide polymorphisms (SNPs; (rs1800462, rs1800460, and rs1142345 in TPMT gene, rs116855232 in NUDT15, rs1127354, rs7270101, rs6051702 in ITPA, and rs2413739 in PACSIN2) were characterized by Taqman SNP genotyping assays. Cox proportional hazard models did not show an impact of TGN levels and variability on relapse. In contrast, after multivariate analysis, relapse hazard ratio (HR) increased in children with ALL of the intermediate risk arm compared with those in standard risk arm (3.44, 95% confidence interval (CI), 1.31-9.05, P = 0.012), and in carriers of the PACSIN2 rs2413739 T allele compared with those with the CC genotype (heterozygotes CT: HR, 2.32, 95% CI, 0.90-5.97, P = 0.081; and homozygous TT: HR, 4.14, 95% CI, 1.54-11.11, P = 0.005). Future studies are needed to confirm the lack of impact of TGN levels and variability on relapse in the AIEOP-BFM ALL trials, and to clarify the mechanism of PACSIN2 rs2413739 on outcome.

The European Medicines Agency (EMA) offers guidance and support to pharmaceutical companies through bilateral discussions called business pipeline meetings (BPMs). An analysis of BPMs in oncology over a 5-year period was conducted to identify common topics and recurring queries. The documents of all BPMs available at the EMA regarding the field of oncology from January 1, 2018, to Decemer 31, 2022, were reviewed. For every query, a main category was assigned, and in case of multiple relevant topics, a secondary category was appointed too. For all queries, the follow-up offered by the EMA was documented, and whether the requested information was available. Subsequently, all queries were scanned for overlapping topics between meetings. From 2018 to 2022, 31 BPMs were held between the EMA and pharmaceutical companies to discuss oncology-related questions, for a total of 397 queries raised. They were classified into 24 topics, of which 15 were common topics (n ≥ 10 queries) with regulatory pathways/guidelines and trial design having the most queries. Post-BPM actions were taken or recommended by the EMA for 41.3% of queries, such as referrals to scientific advice or published guidelines. Forty-three queries were raised at more than one BPM. Targeted therapy, companion diagnostics, institutional collaboration, trial design, and regulatory pathways/guidelines were the most discussed topics in oncology BPMs, with molecular developments being the common denominator. Creating Q&A documents, publishing new guidelines, providing a framework for discussions, and questionnaire-based follow-up research can improve the quality of BPMs, and the accessibility of the information requested during the BPMs.

Endogenous biomarkers are discussed as tools for detection of drug-drug interactions (DDIs) mediated by renal transport proteins, such as organic cation transporter 2 (OCT2), multidrug and toxin extrusion proteins (MATE1 and MATE2-K) and organic anion transporters (OAT1 and OAT3). Whereas sensitivity of some endogenous biomarkers against at least one clinical transporter inhibitor has frequently been shown, intra-study comparisons of the extent of effects of inhibitors on different biomarkers are frequently lacking. Moreover, in vivo specificity of such discussed biomarkers has frequently not been studied. We therefore investigated changes of 10 previously described putative biomarkers for inhibition of OCT2/MATEs, as well as 15 previously described putative biomarkers for OATs in human plasma and urine samples of healthy volunteers in response to treatment with 4 inhibitors of transport proteins [verapamil (P-glycoprotein), rifampin (organic anion transporting polypeptides), cimetidine (OCT2/MATEs), and probenecid (OATs)]. Two of the putative biomarkers had been suggested for both OCT2/MATEs and OATs. All substances were unequivocally identified in an untargeted metabolomics assay. The OCT2/MATE biomarkers choline and trimethylamine N-oxide were both sensitive and specific (median log2-fold changes -1.18 in estimated renal elimination and -0.85 in urinary excretion, respectively). For renal OATs, indoleacetyl glutamine and indoleacetic acid (median log2-fold changes -3.77 and -2.85 in estimated renal elimination, respectively) were the candidates for sensitive and specific biomarkers with the most extensive change, followed by taurine, indolelactic acid, and hypoxanthine. This comprehensive study adds further knowledge on sensitivity and specificity of 23 previously described biomarkers of renal OCT2/MATE- and OAT-mediated DDIs.

Immunogenicity is critical for biologics. However, reference biologics labeling documents do not necessarily mention immunogenicity impact, rendering the development of biosimilars more challenging. We aimed to investigate the comparative assessment of immunogenicity profiles between biosimilars and their respective reference biologics in the review reports of the biosimilar monoclonal antibody applications approved by the Center for Drug Evaluation and Research (CDER), US Food and Drug Administration (FDA) as of March 13, 2022, covering 22 applications approved between April 5, 2016, and December 17, 2021. The maximum differences in anti-drug antibody (ADA) and neutralizing antibody (NAb) incidences between biosimilars and reference products mostly fell within ± 15% (-13.6% to 12%) and ± 20% (-17.4% to 17.1%, except extreme values of -23.4% and 66.7%), respectively. In comparison with antineoplastic agents, more immunosuppressants had ADA-positive (11/11, 100.0% vs. 8/10, 80.0%)/NAb-positive (11/11, 100.0% vs. 3/10, 30.0%) subjects, and the distribution of the aforementioned incidence differences was wider. The investigated biosimilars with available data for analysis demonstrated a high degree of consistency with their reference products in terms of the impact on pharmacokinetic parameters. No increase in immunogenicity was found in available switching studies. Most (16/22, 72.7%) biosimilars were issued post-marketing requirements that were not directly related to immunogenicity concerns. The FDA considered the totality of evidence assessing clinical consequences of immunogenicity differences, if any. Additional information on titers and subgroup analysis may be warranted to elucidate the critical attributes of immunogenicity impact and to aid in forming cost-effective strategies for biosimilar development.

The European Medicines Agency supervises medicines' safe and effective use throughout the product's life cycle by, for example, monitoring the implementation of risk minimisation measures (RMMs). Limited information is available on factors associated with effectiveness of RMMs. This study reviews post-authorisation safety studies (PASS) evaluating the effectiveness of RMMs assessed by the Pharmacovigilance Risk Assessment Committee (PRAC) between 2016 and 2021. PASS assessment reports finalized by PRAC between 1st of January 2016 and 31st of December 2021 were compiled from non-public EMA databases and PASS characteristics were extracted. Of the 94 PASS included, 64.9% aimed to measure healthcare professionals' awareness, knowledge, and behaviour regarding RMMs. 68.1% of the 94 PASS used primary data, 23.4% used secondary data sources, and 8.5% used both. A cross-sectional study design was most frequently applied (76.6%), followed by a cohort study design (27.7%). Nearly 40% of the included PASS did not render a conclusion on RMM effectiveness. Of the 60% that did render a conclusion, 80% were deemed effective. Only minor differences in characteristics were found when stratified by outcome (i.e., effective RMM, ineffective RMM, and no conclusion on RMM effectiveness). To conclude, four out of ten PASS assessing impact of RMMs did not render a conclusion on RMM effectiveness. No clear differences in PASS characteristics were found in relation to their outcomes, indicating that additional research is needed to understand better the underlying reasons for PASS being inconclusive.

Precision medicine has evolved from the application of pharmacogenetic biomarkers to the prospective development of targeted therapies in patients with specific molecular/genetic subtypes of disease to truly "N-of-1" medicines targeted to very small numbers of patients - in some cases, a single identified patient. This latter iteration of precision medicine presents unprecedented opportunities for patients with severe, life-threatening, or life-limiting diseases. At the same time, these modalities present complex scientific, clinical, and regulatory challenges. To realize the promise of individualized medicines, a multistakeholder approach to streamlining medical diagnoses, advancing the technologies that enable development of these therapeutic modalities, and re-envisioning collaborative environments for access and evidence generation is of critical importance. Herein, we highlight some of these challenges and opportunities.

Patho-physiological changes in liver cirrhosis create portacaval shunts that allow blood flow to bypass the hepatic portal vein into the systemic circulation affecting drug pharmacokinetics (PKs). The objectives of this work were to implement a physiologically-based pharmacokinetic (PBPK) framework describing shunted blood flows in virtual patients with differing degrees of liver cirrhosis; and to assess the minimal and full PBPK model's performance using drugs with intermediate to high hepatic extraction. Single dose concentration-time profiles and PK parameters for oral ibrutinib, midazolam, propranolol, and buspirone were simulated in healthy volunteers (HVs) and subjects with cirrhosis (Child-Pugh severity score (CP-A, CP-B, or CP-C)). Model performance was verified by comparing predicted to observed fold-changes in PK parameters between HVs and cirrhotic subjects. The verified model was used to simulate the PK changes for simvastatin in patients with cirrhosis. The predicted area under the curve ratios (AUCCirr :AUCHV ) for ibrutinib were 3.38, 6.87, and 11.46 using the minimal PBPK model with shunt and 1.61, 2.58, and 4.33 without the shunt, these compared with observed values of 4.33, 8.14, and 9.04, respectively. For ibrutinib, propranolol, and buspirone, including a shunt in the PBPK model improved the prediction of the AUCCirr :AUCHV and maximum plasma concentration ratios (CmaxCirr :CmaxHV ). For midazolam, an intermediate extraction drug, the differences were less clear. Simulated simvastatin dose adjustments in cirrhosis suggested that 20 mg in CP-A and 10 mg in CP-B could be used clinically. A mechanistic model-informed understanding of the anatomic and pathophysiology of cirrhosis will facilitate improved dose prediction and adjustment in this vulnerable population.

Monitoring endogenous biomarkers is increasingly used to evaluate transporter-mediated drug-drug interactions (DDIs) in early drug development and may be applied to elucidate changes in transporter activity in disease. 4-pyridoxic acid (PDA) has been identified as the most sensitive plasma endogenous biomarker of renal organic anion transporters (OAT1/3). Increase in PDA baseline concentrations was observed after administration of probenecid, a strong clinical inhibitor of OAT1/3 and also in patients with chronic kidney disease (CKD). The aim of this study was to develop and verify a physiologically-based pharmacokinetic (PBPK) model of PDA, to predict the magnitude of probenecid DDI and predict the CKD-related changes in PDA baseline. The PBPK model for PDA was first developed in healthy population, building on from previous population pharmacokinetic modeling, and incorporating a mechanistic kidney model to consider OAT1/3-mediated renal secretion. Probenecid PBPK model was adapted from the Simcyp database and re-verified to capture its dose-dependent pharmacokinetics (n = 9 studies). The PBPK model successfully predicted the PDA plasma concentrations, area under the curve, and renal clearance in healthy subjects at baseline and after single/multiple probenecid doses. Prospective simulations in severe CKD predicted successfully the increase in PDA plasma concentration relative to healthy (within 2-fold of observed data) after accounting for 60% increase in fraction unbound in plasma and additional 50% decline in OAT1/3 activity beyond the decrease in glomerular filtration rate. The verified PDA PBPK model supports future robust evaluation of OAT1/3 DDI in drug development and increases our confidence in predicting exposure and renal secretion in patients with CKD.

Anti-tumor necrosis factor (anti-TNF) agents are widely applied for patients with inflammatory bowel disease (IBD); however, the timing of the last dosing for IBD pregnancy and time to elimination in anti-TNF agent-exposed infants is controversial. This study aimed to determine the optimal timing for the last dosing of anti-TNF agents (infliximab, adalimumab, and golimumab) in pregnant women with IBD, as well as to investigate the recommended vaccine schedules for infants exposed to these drugs. A physiologically-based pharmacokinetic (PBPK) model of anti-TNF agents was built for adults and extrapolated to pregnant patients, fetuses, and infants. The PBPK models successfully predicted and verified the pharmacokinetics (PKs) of infliximab, adalimumab, and golimumab in pregnancy, fetuses, and infants. The predicted PK data were within two-fold of the observed data. The simulated results were used as timing advice. According to the dose of administration, the suggested timing of the last dosing for infliximab, adalimumab, and golimumab is successfully provided based on PBPK predictions. PBPK models indicated that, for infants, the advocated timing of vaccination is 12, 8, and 5 months after birth for infliximab, adalimumab, and golimumab, respectively. Our study illustrated that PBPK models can provide a valuable tool to predict the PKs of large macromolecules in pregnant women, fetuses, and infants, ultimately informing drug-treatment decisions for pregnancy and vaccination regimens for infants.

This study aims to determine whether CYP2C19 loss-of-function (LoF) variants were associated with long-term ischemic stroke risk in Chinese primary care patients treated with clopidogrel. Patients treated with clopidogrel were ascertained from Chinese electronic medical records linked with a biobank for a retrospective cohort study. Their medical information was examined for the period from January 2018 to December 2021. Two CYP2C19 major loss of function variants (*2:rs4244285 and *3: rs4986893) were genotyped. The clinical outcome was ischemic stroke event. Cox regression analysis was used to evaluate the association between the occurrence of ischemic stroke events and CYP2C19 LoF variants. Covariates included age, gender, body mass index, prior ischemic stroke, transient ischemic attack, hypertension, diabetes mellitus, hyperlipoidemia, smoke status, aspirin use, proton-pump inhibitor use, and statin use. Of the 1,141 patients included in the clopidogrel therapy cohort, 61.9% carried at least one CYP2C19 LoF variant. During a median follow-up period of 12 months, 103 patients (9.0%) had an ischemic stroke. After adjusting for other risk factors, carriers of CYP2C19 LoF variants had significantly higher risk of ischemic stroke compared with non-carriers (hazard ratio: 1.64, 95% confidence interval: 1.06-2.53, P = 0.025). This pharmacogenetic study of clopidogrel provides novel insights into the association between the CYP2C19 LoF variant and long-term stroke risk. We established that there is still a need for CYP2C19 genotype-guided personalized antiplatelet therapy in those who have returned to the primary care setting for clopidogrel prescription.

Nirmatrelvir is a potent and selective severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) main protease inhibitor. Nirmatrelvir co-packaged with ritonavir (as PAXLOVID) received US Food and Drug Administration (FDA) Emergency Use Authorization (EUA) on December 22, 2021, as an oral treatment for coronavirus disease 2019 (COVID-19) and subsequent new drug application approval on May 25, 2023. Pharmacokinetic (PK) capillary blood sampling at-home using Tasso-M20 micro-volumetric sampling device was implemented in the program, including three phase II/III outpatient and several clinical pharmacology studies supporting the EUA. The at-home sampling complemented venous blood sampling procedures to enrich the PK dataset, to decrease the need for patients' site visit for PK sampling, and to allow different sampling approaches for flexibility and convenience. To demonstrate concordance/equivalence, bridging between venous plasma and Tasso dried blood results was conducted by comparing concentrations and derived PK parameters from both sampling approaches. In addition, a two-compartment population PK model was utilized to bridge the plasma and Tasso data by estimating the PK parameters using blood-to-plasma ratio as a slope parameter. Operational challenges were successfully managed to implement at-home PK sampling in global phase II/III trials. Sample quality was generally very good with less than 3% samples deemed as "not usable" from over 800 samples collected in all the studies. Experience gained from sites and patients will guide future broader implementations.

Prior studies have demonstrated that misclassification of study variables due to electronic health record (EHR)-discontinuity can be mitigated by restricting EHR-based analyses to subjects with high predicted EHR-continuity based on a simple algorithm. In this study, we compared EHR continuity in populations covered by Medicare, Medicaid, or commercial insurance. Using claims-linked EHRs from a multicenter network in Massachusetts, including Medicare (MA EHR-Medicare cohort) and Medicaid (MA EHR-Medicaid cohort) claims data; and TriNetX (TriNetX cohort) claims-linked EHR data from 11 US-based healthcare organizations, we assessed (1) EHR-continuity quantified by proportion of encounters captured by EHR (capture proportion (CP)); (2) area under receiver operating curve (AUROC) of previously validated model to identify patients with high EHR-continuity (CP ≥ 0.6); (3) misclassification of 40 patient characteristics, quantified by average standardized absolute mean difference (ASAMD). Study participants were ≥ 65 years (Medicare) or ≥ 18 years (Medicaid, TriNetX) with ≥ 365 days of continuous insurance enrollment overlapping with an EHR encounter. We found that the mean CP was 0.30, 0.18, and 0.19 and AUROC of the prediction model to identify patients with high EHR-continuity was 0.92, 0.89, and 0.77 in the MA EHR-Medicare, MA EHR-Medicaid, and TriNetX cohorts, respectively. Restricting to patients with predicted EHR-continuity percentile of top 20%, 50%, and 50% in MA EHR-Medicare, MA EHR-Medicaid, and TriNetX cohorts resulted in acceptable levels of misclassification (ASAMD < 0.1). Using a prediction model to identify cohorts with high EHR-continuity can improve validity, but cutoffs to achieve this goal vary by population.

Loss-of-function (LoF) alleles of cytochrome P450 2C19 (CYP2C19), which are prevalent in East Asians, are linked to high platelet reactivity (HPR) phenotype and poor prognosis. We aimed to investigate the incremental predictive value of HPR combined with CYP2C19 genotype in predicting outcomes after drug-eluting stent (DES) implantation. The patients treated with platelet function and genotype-related long-term prognosis in drug-eluting stent (PTRG-DES) consortium enrolled a total of 13,160 Korean patients treated with DES who had platelet function test (PFT) or CYP2C19 genotype, of which, 6,717 patients with PFT and genotype together were categorized. HPR was defined as VerifyNow ≥ 252 P2Y12 reaction unit. The primary outcome was the incidence of major adverse cardiac and cerebrovascular event (MACCE) 5 years after treatment. The patients with both HPR and CYP2C19 LoF/LoF had the highest MACCE rates (6.2%) and increased MACCE risk (adjusted hazard ratio: 1.89, 95% confidence interval: 1.20-2.91, P = 0.006) compared with those without both HPR and CYP2C19 LoF/LoF. There was no effect of interaction between HPR and CYP2C19 genotype on the primary outcome (P = 0.424). Adding combined HPR and CYP2C19 genotype to the conventional model had an incremental influence in predicting MACCE and stent thrombosis. Compared to the model including HPR or CYP2C19 genotype alone, a combination model significantly improved the risk stratification for stent thrombosis but not MACCE. In DES-treated East Asian patients, the combined evaluation of PFT results and CYP2C19 genotyping might improve risk prediction of ischemic events during clopidogrel treatment.

Randomized controlled trials (RCTs) remain the gold standard for evaluating treatment efficacy, but real-world evidence can supplement RCT results. Tocilizumab was not found to reduce 28-day mortality in a phase III, double-blind, placebo-controlled trial (COVACTA) among hospitalized patients with severe coronavirus disease 2019 (COVID-19) pneumonia. We created a real-world external comparator arm mirroring the COVACTA trial to confirm findings and assess the feasibility of using an external comparator arm to supplement an RCT. Eligible COVACTA participants in both the tocilizumab treatment and placebo arms were matched 1:1 using propensity score matching to persons without tocilizumab exposure in an external comparator arm. Adjusted Cox proportional hazard models estimated differences in 28-day mortality comparing COVACTA participants to matched external comparator arm participants. Patients in the COVACTA tocilizumab treatment arm had a similar risk of death compared with patients in the external comparator arm (hazard ratio (HR): 1.09, 95% confidence interval (CI): 0.64-1.84) with similar estimated 28-day mortality in the COVACTA tocilizumab treatment arm compared with the external comparator arm (18%, 95% CI: 13-24 vs. 19%, 95% CI: 13-24, P > 0.9). COVACTA placebo treatment arm participants had a similar risk of mortality (adjusted HR: 0.69, 95% CI: 0.32-1.46) compared with the external comparator arm. Using an external comparator arm has the potential to supplement RCT data and support results of primary RCT analyses.

Transient receptor potential Ankyrin 1 (TRPA1) is an ion channel expressed by sensory neurons, where it mediates pain signalling. Consequently, it has emerged as a promising target for novel analgesics, yet to date no TRPA1 antagonists have been approved for clinical use. In the present translational study, we utilized dermal blood flow changes evoked by TRPA1 agonist cinnamaldehyde as a target engagement biomarker to investigate the in vivo pharmacology of LY3526318, a novel TRPA1 antagonist. In rats, LY3526318 (1, 3 and 10 mg/kg, p.o.) dose-dependently reduced the cutaneous vasodilation typically observed following topical application of 10% v/v cinnamaldehyde. The inhibition was significant at the site of cinnamaldehyde application and also when including an adjacent area of skin. Similarly, in a cohort of 16 healthy human volunteers, LY3526318 administration (10, 30 and 100 mg, p.o.) dose-dependently reduced the elevated blood flow surrounding the site of 10% v/v cinnamaldehyde application, with a trend towards inhibition at the site of application. Comparisons between both species reveal that the effects of LY3526318 on the cinnamaldehyde-induced dermal blood flow are greater in rats relative to humans, even when adjusting for cross-species differences in potency of the compound at TRPA1. Exposure-response relationships suggest that a greater magnitude response may be observed in humans if higher antagonist concentrations could be achieved. Taken together, these results demonstrate that cinnamaldehyde-evoked changes in dermal blood flow can be utilized as a target engagement biomarker for TRPA1 activity and that LY3526318 antagonizes the ion channel both in rats and humans.

A novel haplotype composed of two non-coding variants, CYP2C18 NM_000772.3:c.*31T (rs2860840) and NM_000772.2:c.819+2182G (rs11188059), referred to as "CYP2C:TG," was recently associated with ultrarapid metabolism of various CYP2C19 substrates. As the underlying mechanism and clinical relevance of this effect remain uncertain, we analyzed existing in vivo and in vitro data to determine the magnitude of the CYP2C:TG haplotype effect. We assessed variability in pharmacokinetics of CYP2C19 substrates, including citalopram, sertraline, voriconazole, omeprazole, pantoprazole, and rabeprazole in 222 healthy volunteers receiving one of these six drugs. We also determined its impact on CYP2C8, CYP2C9, CYP2C18, and CYP2C19 protein abundance in 135 human liver tissue samples, and on CYP2C18/CYP2C19 activity in vitro using N-desmethyl atomoxetine formation. No effects were observed according to CYP2C:TG haplotype or to CYP2C19*1+TG alleles (i.e., CYP2C19 alleles containing the CYP2C:TG haplotype). In contrast, CYP2C19 intermediate (e.g., CYP2C19*1/*2) and poor metabolizers (e.g., CYP2C19*2/*2) showed significantly higher exposure in vivo, lower CYP2C19 protein abundance in human liver microsomes, and lower activity in vitro compared with normal, rapid (i.e., CYP2C19*1/*17), and ultrarapid metabolizers (i.e., CYP2C19*17/*17). Moreover, a tendency toward lower exposure was observed in ultrarapid metabolizers compared with rapid metabolizers and normal metabolizers. Furthermore, when the CYP2C19*17 allele was present, CYP2C18 protein abundance was increased suggesting that genetic variation in CYP2C19 may be relevant to the overall metabolism of certain drugs by regulating not only its expression levels, but also those of CYP2C18. Considering all available data, we conclude that there is insufficient evidence supporting clinical CYP2C:TG testing to inform drug therapy.