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The US Food and Drug Administration draft drug interaction guidance recommends that 400 mg ketoconazole (KTZ) be administered once daily for several days (QD400) for maximal CYP3A inhibition. Some investigators suggest that a single dose of 400 mg (SD400) KTZ is sufficient given its short half-life (t(1/2) approximately 3-5 hr). To determine the impact of KTZ regimens on CYP3A inhibition, we simulated AUC fold-change (AUCR) in the presence of SD400, QD400, or 200 mg twice-daily (BID200) KTZ for theoretical CYP3A substrates. Ratios of AUCR (AUCR(QD400)/AUCR(SD400) and AUCR(BID200) AUCR(QD400)) increase with increasing bioavailability and increasing substrate t(1/2). The SD400 KTZ regimen may provide maximal inhibition only for a subset of substrates (ie, low bioavailability and short t(1/2)). For substrates with t(1/2) longer than that of KTZ, multiple KTZ dosing is critical and BID200 appears to provide greater inhibition than QD400. Also, timing of KTZ administration should be optimized to allow maximal presystemic enzyme inhibition prior to substrate administration. [ABSTRACT FROM AUTHOR]

ABSTRACTObjective:One-quarter of all U.S. chronic-disease deaths occur in nursing homes, yet few studies examine palliative care quality in these settings. This study tests whether racial and/or age-based differences in end-of-life care exist in these institutional settings.Methods:We abstracted residents' charts (N = 1133) in 12 nursing homes. Researchers collected data on indicators of palliative care in two domains of care-advance care planning and pain management-and on residents' demographic and health status variables. Analyses tested for differences by race and age.Results:White residents were more likely than minorities to have DNR orders (69.5% vs. 37.3%), living wills (39% vs. 5%), and health care proxies (36.2% vs. 11.8%; p < .001 for each). Advance directives were highly and positively correlated with age. In-depth advance care planning discussions between residents, families, and health care providers were rare for all residents, irrespective of demographic characteristics. Nursing staff considered older residents to have milder and less frequent pain than younger residents. We found no disparities in pain management based on race.Significance of results:To the extent that advance care planning improves care at the end of life, racial minorities in nursing homes are disadvantaged compared to their white fellow residents. Focusing on in-depth discussions of values and goals of care can improve palliative care for all residents and may help to ameliorate racial disparities in end-of-life care. Staff should consider residents of all ages as appropriate recipients of advance care planning efforts and should be cognizant of the fact that individuals of all ages can experience pain. Nursing homes may do a better job than other health care institutions in eliminating racial disparities in pain management. [ABSTRACT FROM AUTHOR]

Orofacial clefts (OFCs) are one of the most common types of structural birth defects. The etiologies are complicated, involving with genetic, epigenetic, and environmental factors. Studies have found that maternal diabetes and metabolic syndrome are associated with a higher risk of OFCs in offspring. Metabolic syndrome is a clustering of several disease risk factors, including hyperglycemia, dyslipidemia, obesity, and hypertension. Metabolic disease during pregnancy can increase risk of adverse outcomes and significantly influence fetal development, including orofacial formation and fusion. An altered metabolic state may contribute to developmental disorders or congenital defects including OFCs, potentially through epigenetic modulations, such as histone modification, DNA methylation, and noncoding RNA expression to alter activities of critical morphogenetic signaling or related developmental genes. This review summarizes the currently available evidence and underlying mechanisms of how the maternal metabolic syndrome is associated with OFCs in mostly human and some animal studies. It may provide a better understanding of the interactions between intrauterine metabolic status and fetal orofacial development which might be applied toward prevention and treatments of OFCs., (© 2023 Wiley Periodicals LLC.)

RNA-based oligonucleotide therapeutics are revolutionizing drug development for disease treatment. This class of therapeutics differs from small molecules and protein therapeutics in various ways, including both its mechanism of action and clinical pharmacology characteristics. These unique characteristics, along with evolving oligonucleotide-associated conjugates allowing specific tissue targeting, have fueled interest in the evaluation of RNA-based oligonucleotide therapeutics in a rapidly increasing number of therapeutic areas. With these unique attributes as well as growing therapeutic potential, oligonucleotide therapeutics have generated significant interest from a clinical pharmacology perspective. The Food and Drug Administration (FDA) previously published results of a survey that summarized clinical pharmacology studies supporting oligonucleotide therapies approved and in development between 2012 and 2018. Since the first approval of a small interfering RNA (siRNA) therapeutic in 2018, this class of modalities has gained momentum in various therapeutic areas. Hence, a comprehensive examination of the clinical pharmacology of FDA-approved siRNA therapeutics would benefit the path forward for many stakeholders. Thus, in this current review, we thoroughly examine and summarize clinical pharmacology data of the FDA-approved siRNA therapeutics approved from 2018 (year of first approval) to 2022, aimed at facilitating future drug development and regulatory decision making. SIGNIFICANCE STATEMENT: This review systematically summarizes the clinical pharmacology information of Food and Drug Administration (FDA)-approved small interfering RNAs (siRNA) therapeutics. SiRNAs are revolutionizing the drug development field. Unique clinical pharmacology characteristics represent a differentiating factor for this class of therapeutics. The FDArecently published a draft guidance for clinical pharmacology considerations for developing oligonucleotide therapeutics. As clinical development of this class of therapeutics is fast growing, this review will inform discovery and clinical-stage evaluation of upcoming siRNA-associated drug candidates., (U.S. Government work not protected by U.S. copyright.)

Comprehensive characterization of transporter mediated drug-drug interactions (DDIs) is important to formulate clinical management strategies and ensure the safe and effective use of concomitantly administered drugs. The potential of a drug to inhibit transporters is predicted by comparing the ratio of the relevant concentration (depending on the transporter) and the half maximum inhibitory concentration to a predefined "cutoff" value. If the ratio is greater than the cutoff value, modeling approaches such as physiologically based pharmacokinetic modeling or a clinical DDI trial may be recommended. Because false-positive (in vitro data suggest the potential for a DDI, whereas no significant DDI is observed in vivo) and false-negative (in vitro data does not suggest the potential for a DDI, whereas significant DDI is observed in vivo) outcomes have been observed, there is interest in exploring additional approaches to facilitate prediction of transporter-mediated DDIs. The idea of assessing changes in the concentration of endogenous biomarkers (which are substrates of clinically relevant transporters) to gain insight on the potential for a drug to inhibit transporter activity has received widespread attention. This brief report describes how endogenous biomarkers may help to expand the DDI assessment toolkit, highlights some current knowledge gaps, and outlines a conceptual framework that may complement the current paradigm of predicting the potential for transporter-mediated DDIs., (Published 2022. This article is a U.S. Government work and is in the public domain in the USA.)

In this report, we describe our scientific approach for including effluent flow rate (Q E )-based dosing recommendations of cefiderocol for patients receiving continuous renal replacement therapy (CRRT) in the product labeling. The total clearance (CL) of cefiderocol in patients receiving CRRT was estimated as the sum of patients' nonrenal clearance (CL nonrenal ) and extracorporeal clearance by CRRT (CL CRRT ), based on the following rationale: (a) The renal clearance (CL renal ) of cefiderocol is assumed to be negligible in patients receiving CRRT, (b) CL nonrenal represents the CRRT patients' own remaining systemic clearance and is estimated from the observed clearance in participants with creatinine clearance (CLcr) < 15 mL/minute without undergoing hemodialysis, and (c) CL CRRT was estimated by the product of unbound (free) fraction of plasma drug concentration (f u ) and Q E because the free fraction of low-molecular-weight compounds like cefiderocol (752 Da) can be completely filtered by CRRT, regardless of CRRT modality. Hence, cefiderocol CL in CRRT patients was calculated by the equation of CL = CL nonrenal  + f u  × Q E . Accordingly, the cefiderocol dosing regimens for patients receiving CRRT in clinically relevant ranges of Q E were determined with the goal of achieving an average daily area under the concentration-time curve (AUC) observed in patients not receiving CRRT. Subsequently, pharmacokinetic (PK) simulations demonstrated that cefiderocol PK profiles following the Q E -based dosing in patients receiving CRRT would be similar to those in patients not receiving CRRT., (Published 2022. This article is a U.S. Government work and is in the public domain in the USA.)

In 2018, the FDA approved plazomicin for the treatment of complicated urinary tract infections (cUTI) including pyelonephritis in adult patients with limited or no alternative treatment options. The objective of this article is to provide the scientific rationales behind the recommended dosage regimen and therapeutic drug monitoring (TDM) of plazomicin in cUTI patients with renal impairment. A previous population pharmacokinetic (PK) model was used to evaluate the dosage regimen in cUTI patients with different degrees of renal impairment. The exposure-response analysis was conducted to identify the relationship between plazomicin exposure and nephrotoxicity incidence in cUTI patients with renal impairment. Classification and regression tree (CART) analysis was utilized to assess the TDM strategy. The receiver operating characteristics curve was plotted to compare two TDM thresholds in cUTI patients with renal impairment. The analyses suggested that dose reduction is necessary for cUTI patients with moderate or severe renal impairment. TDM should be implemented for cUTI patients with mild, moderate, or severe renal impairment to reduce the risk of nephrotoxicity. The trough concentration of 3 μg/mL is a reasonable TDM threshold to reduce the nephrotoxicity incidence while maintaining efficacy in cUTI patients with renal impairment. The application of population PK modeling, exposure-response analysis, and CART analysis allowed for the evaluation of a dosage regimen and TDM strategy for plazomicin in cUTI patients with renal impairment. Our study demonstrates the utility of pharmacometrics and statistical approaches to inform a dosage regimen and TDM strategy for drugs with narrow therapeutic windows.

Remdesivir (RDV) is the first drug approved by the US Food and Drug Administration (FDA) for the treatment of coronavirus disease 2019 (COVID-19) in certain patients requiring hospitalization. As a nucleoside analogue prodrug, RDV undergoes intracellular multistep activation to form its pharmacologically active species, GS-443902, which is not detectable in the plasma. A question arises that whether the observed plasma exposure of RDV and its metabolites would correlate with or be informative about the exposure of GS-443902 in tissues. A whole body physiologically-based pharmacokinetic (PBPK) modeling and simulation approach was utilized to elucidate the disposition mechanism of RDV and its metabolites in the lungs and liver and explore the relationship between plasma and tissue pharmacokinetics (PK) of RDV and its metabolites in healthy subjects. In addition, the potential alteration of plasma and tissue PK of RDV and its metabolites in patients with organ dysfunction was explored. Our simulation results indicated that intracellular exposure of GS-443902 was decreased in the liver and increased in the lungs in subjects with hepatic impairment relative to the subjects with normal liver function. In subjects with severe renal impairment, the exposure of GS-443902 in the liver was slightly increased, whereas the lung exposure of GS-443902 was not impacted. These predictions along with the organ impairment study results may be used to support decision making regarding the RDV dosage adjustment in these patient subgroups. The modeling exercise illustrated the potential of whole body PBPK modeling to aid in decision making for nucleotide analogue prodrugs, particularly when the active metabolite exposure in the target tissues is not available., (Published 2021. This article is a U.S. Government work and is in the public domain in the USA.)

Background: An antibacterial drug's susceptibility test interpretive criteria (STIC) are determined by integrating clinical, microbiological and pharmacokinetic-pharmacodynamic (PK-PD) data. PTA analysis plays a pivotal or supportive role in STIC determination and is heavily dependent on the PK-PD target values determined from animal PK-PD studies. Therefore, variations in PK-PD target values may impact STIC determination. Factors contributing to variation in the PK-PD target values include the number of and MICs for bacterial isolates used in animal PK-PD studies., Objectives: To analyse the relationship between PK-PD target values and MICs, describe the variations in PK-PD target values of isolates and evaluate whether the proposed/target STICs were within the ranges of the MICs for isolates used in animal PK-PD studies., Methods: A database was compiled for this research by screening animal PK-PD study reports submitted to the FDA from 10 new drug applications (NDAs)., Results: A relationship evaluation between PK-PD target values and MICs for tested isolates for seven drugs (that used AUC/MIC ratio as the PK-PD index) showed that, generally, the AUC/MIC values decreased with an increase in MIC. These target values were highly variable, with the percentage coefficient of variation ranging between 1% and 132% for isolates having the same MIC. For 16/27 (59%) drug/bacteria combinations from all 10 drugs, the proposed/target STICs were higher than the highest MIC for bacteria isolates evaluated, while 6/27 (22.5%) were lower., Conclusions: This research suggests that careful considerations related to selection of bacterial isolates for animal PK-PD studies could strengthen the STIC determination process., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

For treatment of severe malaria, the World Health Organization recommends 3 mg/kg intravenous artesunate in pediatric patients weighing less than 20 kg. Here we describe the Food and Drug Administration's rationale for selecting 2.4 mg/kg in pediatric patients weighing less than 20 kg based on literature review and independent analyses., (Published by Oxford University Press for the Infectious Diseases Society of America 2021.)

A critical step to evaluate the potential in vivo antiviral activity of a drug is to connect the in vivo exposure to its in vitro antiviral activity. The Anti-SARS-CoV-2 Repurposing Drug Database is a database that includes both in vitro anti-SARS-CoV-2 activity and in vivo pharmacokinetic data to facilitate the extrapolation from in vitro antiviral activity to potential in vivo antiviral activity for a large set of drugs/compounds. In addition to serving as a data source for in vitro anti-SARS-CoV-2 activity and in vivo pharmacokinetic information, the database is also a calculation tool that can be used to compare the in vitro antiviral activity with in vivo drug exposure to identify potential anti-SARS-CoV-2 drugs. Continuous development and expansion are feasible with the public availability of this database., (Published 2021. This article is a U.S. Government work and is in the public domain in the USA. CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

Patients with multiple chronic conditions, including more advanced chronic kidney disease (CKD), are often excluded from clinical trials, creating challenges in deriving appropriate dosing information and labeling. This article summarizes the May 7, 2019, US Food and Drug Administration Pharmaceutical Science and Clinical Pharmacology Advisory Committee Meeting, which solicited expert opinions on how to enroll patients with more advanced CKD into clinical trials as well as the assumptions behind and different approaches of exposure-matching., (© 2021 The Authors. Clinical Pharmacology & Therapeutics © 2021 American Society for Clinical Pharmacology and Therapeutics.)

This literature review aims to provide a comprehensive current summary of the pathogenesis, clinical features, disease course, host immune responses, and current investigational antiviral and immunomodulatory pharmacotherapies to facilitate the development of future therapies and measures for prevention and control., (Published 2020. This article is a U.S. Government work and is in the public domain in the USA.)

The objectives of this study were to evaluate the effect of hemodialysis (HD) on the pharmacokinetics (PK) of meropenem/vaborbactam, an approved beta-lactam/beta-lactamase inhibitor combination, and provide the rationale for the recommended timing of meropenem/vaborbactam administration relative to HD in end-stage renal disease (ESRD) patients. Population PK models were developed separately for meropenem and vaborbactam in subjects with normal renal function and different degrees of renal impairment, including those receiving HD. Simulations were performed to evaluate the exposure of meropenem and vaborbactam in ESRD patients who received a fixed dose of 0.5 g/0.5 g meropenem/vaborbactam every 12 hours as a 3-hour intravenous infusion under various drug administration schedules relative to HD. The probability of target attainment (PTA) analyses were conducted with pharmacokinetic/pharmacodynamic (PK/PD) targets of meropenem and vaborbactam. Simulations showed that HD reduces the accumulation of vaborbactam, but the exposure of vaborbactam is still above the PK/PD target regardless of whether meropenem/vaborbactam is administered predialysis or postdialysis. For meropenem, drug infusion completed right prior to initiation of HD may substantially reduce exposure leading to poor PTA results. In contrast, drug infusion completed at least 2 hours prior to initiation of HD is not predicted to result in efficacy loss based on PTA analysis. The results of simulation indicate that meropenem/vaborbactam infusion completed at least 2 hours prior to initiation of HD or administered immediately after the end of HD can avoid potential efficacy loss in ESRD patients., (Published 2020. This article is a U.S. Government work and is in the public domain in the USA.)

Clinical drug-drug interactions (DDIs) can occur when multiple drugs are taken by the same patient. Significant DDIs can result in clinical toxicity or treatment failure. Therefore, DDI assessment is an integral part of drug development and the benefit-risk assessment of new therapies. Regulatory agencies including the Food and Drug Administration, the European Medicines Agency, and the Pharmaceuticals and Medical Devices Agency of Japan have made recommendations in their DDI guidance documents on various methodologies (in vitro, in silico, and clinical) to assess DDI potential and inform patient management strategies. This commentary focuses on clinical DDI evaluation for the purpose of drug development and regulatory evaluation., (Published by Elsevier Inc.)

Evaluation of drug-drug interaction (DDI) risk is vital to establish benefit-risk profiles of investigational new drugs during drug development. In vitro experiments are routinely conducted as an important first step to assess metabolism- and transporter-mediated DDI potential of investigational new drugs. Results from these experiments are interpreted, often with the aid of in vitro-in vivo extrapolation methods, to determine whether and how DDI should be evaluated clinically to provide the basis for proper DDI management strategies, including dosing recommendations, alternative therapies, or contraindications under various DDI scenarios and in different patient population. This article provides an overview of currently available in vitro experimental systems and basic in vitro-in vivo extrapolation methodologies for metabolism- and transporter-mediated DDIs., (Published by Elsevier Inc.)

This issue of Clinical Pharmacology & Therapeutics focuses on emerging infections. The outbreaks of the vaccine-preventable diseases (e.g., measles) and the emerging pathogens (e.g., Ebola) show us how small the world has become. These outbreaks also show the pressing need for effective public education and development of novel therapies. This issue covers various aspects of relevant therapeutic topics ranging from preclinical models, pharmacokinetics, pharmacodynamics, pharmacogenomics, and clinical trial results, to education efforts in this area. Pharmacokinetic/dynamic modeling had an appreciable role in reducing the morbidity and mortality associated with human immunodeficiency virus and hepatitis C virus, recent emerging infections. However, these gains could be lessened by poor adherence to therapies, which has contributed to the development of multidrug-resistant tuberculosis. We must not forget lessons from previous infections, or they may reemerge., (© 2015 ASCPT.)

Background and Objective: The US Food and Drug Administration (FDA) has seen a recent increase in the application of physiologically based pharmacokinetic (PBPK) modeling towards assessing the potential of drug-drug interactions (DDI) in clinically relevant scenarios. To continue our assessment of such approaches, we evaluated the predictive performance of PBPK modeling in predicting cytochrome P450 (CYP)-mediated DDI., Methods: This evaluation was based on 15 substrate PBPK models submitted by nine sponsors between 2009 and 2013. For these 15 models, a total of 26 DDI studies (cases) with various CYP inhibitors were available. Sponsors developed the PBPK models, reportedly without considering clinical DDI data. Inhibitor models were either developed by sponsors or provided by PBPK software developers and applied with minimal or no modification. The metric for assessing predictive performance of the sponsors' PBPK approach was the R predicted/observed value (R predicted/observed = [predicted mean exposure ratio]/[observed mean exposure ratio], with the exposure ratio defined as [C max (maximum plasma concentration) or AUC (area under the plasma concentration-time curve) in the presence of CYP inhibition]/[C max or AUC in the absence of CYP inhibition])., Results: In 81 % (21/26) and 77 % (20/26) of cases, respectively, the R predicted/observed values for AUC and C max ratios were within a pre-defined threshold of 1.25-fold of the observed data. For all cases, the R predicted/observed values for AUC and C max were within a 2-fold range., Conclusion: These results suggest that, based on the submissions to the FDA to date, there is a high degree of concordance between PBPK-predicted and observed effects of CYP inhibition, especially CYP3A-based, on the exposure of drug substrates.

Nine static models (seven basic and two mechanistic) and their respective cutoff values used for predicting cytochrome P450 3A (CYP3A) inhibition, as recommended by the US Food and Drug Administration and the European Medicines Agency, were evaluated using data from 119 clinical studies with orally administered midazolam as a substrate. Positive predictive error (PPE) and negative predictive error (NPE) rates were used to assess model performance, based on a cutoff of 1.25-fold change in midazolam area under the curve (AUC) by inhibitor. For reversible inhibition, basic models using total or unbound systemic inhibitor concentration [I] had high NPE rates (46-47%), whereas those using intestinal luminal ([I]gut) values had no NPE but a higher PPE. All basic models for time-dependent inhibition had no NPE and reasonable PPE rates (15-18%). Mechanistic static models that incorporate all interaction mechanisms and organ specific [I] values (enterocyte and hepatic inlet) provided a higher predictive precision, a slightly increased NPE, and a reasonable PPE. Various cutoffs for predicting the likelihood of CYP3A inhibition were evaluated for mechanistic models, and a cutoff of 1.25-fold change in midazolam AUC appears appropriate.

Single tablet, once-daily HIV treatment regimens offer patient convenience, the potential for increased adherence, and fewer patient-related dosing errors [1] . Stribild® (manufactured and marketed by Gilead Sciences; referred to as "applicant" in this report), a 4-drug fixed-dose combination (FDC) tablet, is approved for the treatment of HIV-1 infection in treatment-naïve adult patients. Stribild® contains elvitegravir (an integrase strand transfer inhibitor), cobicistat (an inhibitor of cytochrome P450 enzymes), and the nucleoside/nucleotide reverse transcriptase inhibitors emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF)., (© 2013, The American College of Clinical Pharmacology.)

Modern drugs are used to treat and prevent diseases that previously led to morbidity and mortality. There is a high cost to this achievement--investment for each successful drug can exceed $1.8 billion. Late-phase drug candidate failure decreases efficiency of drug development because each failure represents lost or delayed opportunity to develop successful drugs. Collaboration of stakeholders and the use of new science and knowledge management can reduce late-phase failure and accelerate drug development.

Telithromycin is a substrate and an inhibitor of cytochrome P450 3A (CYP3A4), with dose- and time-dependent nonlinear pharmacokinetics (PK). We hypothesized that the time-dependent inhibition (TDI) of CYP3A4 was responsible for the nonlinear PK of telithromycin and then used physiologically based PK (PBPK) modeling and simulation to verify this mechanism. Telithromycin PBPK models integrating in vitro, in silico, and in vivo PK data ruled out the contribution of enzyme/transporter saturation and suggested that TDI is a plausible mechanism for PK nonlinearity. The model successfully predicted the clinical interaction with the CYP3A4 substrate midazolam, as verified by external data not used for the model-building (intravenous (i.v.) and oral (p.o.) midazolam area under the concentration-time curve (AUC) ratio with/without concurrent telithromycin administration: 3.26 and 6.72 predicted vs. 2.20 and 6.11 observed, respectively). Models assuming reversible inhibition failed to predict such strong CYP3A4 inhibition. In the absence of in vitro TDI data, a PBPK model can be used to incorporate TDI mechanisms based on nonlinear PK data to predict clinical drug-drug interactions.

Chronic kidney disease, or renal impairment (RI) can increase plasma levels for drugs that are primarily renally cleared and for some drugs whose renal elimination is not a major pathway. We constructed physiologically based pharmacokinetic (PBPK) models for 3 nonrenally eliminated drugs (sildenafil, repaglinide, and telithromycin). These models integrate drug-dependent parameters derived from in vitro, in silico, and in vivo data, and system-dependent parameters that are independent of the test drugs. Plasma pharmacokinetic profiles of test drugs were simulated in subjects with severe RI and normal renal function, respectively. The simulated versus observed areas under the concentration versus time curve changes (AUCR, severe RI/normal) were comparable for sildenafil (2.2 vs 2.0) and telithromycin (1.6 vs 1.9). For repaglinide, the initial, simulated AUCR was lower than that observed (1.2 vs 3.0). The underestimation was corrected once the estimated changes in transporter activity were incorporated into the model. The simulated AUCR values were confirmed using a static, clearance concept model. The PBPK models were further used to evaluate the changes in pharmacokinetic profiles of sildenafil metabolite by RI and of telithromycin by RI and co-administration with ketoconazole. The simulations demonstrate the utility and challenges of the PBPK approach in evaluating the pharmacokinetics of nonrenally cleared drugs in subjects with RI.

Physiologically based pharmacokinetic (PBPK) modeling and simulation is a tool that can help predict the pharmacokinetics of drugs in humans and evaluate the effects of intrinsic (e.g., organ dysfunction, age, genetics) and extrinsic (e.g., drug-drug interactions) factors, alone or in combinations, on drug exposure. The use of this tool is increasing at all stages of the drug development process. This report reviews recent instances of the use of PBPK in decision-making during regulatory review. The examples are based on Center for Drug Evaluation and Research reviews of several submissions for investigational new drugs (INDs) and new drug applications (NDAs) received between July 2008 and June 2010. The use of PBPK modeling and simulation facilitated the following types of decisions: the need to conduct specific clinical pharmacology studies, specific study designs, and appropriate labeling language. The report also discusses the challenges encountered when PBPK modeling and simulation were used in these cases and recommends approaches to facilitating full utilization of this tool.

Pharmacokinetic drug interactions can lead to serious adverse events or decreased drug efficacy. The evaluation of a new molecular entity's (NME's) drug-drug interaction potential is an integral part of risk assessment during drug development and regulatory review. Alteration of activities of enzymes or transporters involved in the absorption, distribution, metabolism, or excretion of a new molecular entity by concomitant drugs may alter drug exposure, which can impact response (safety or efficacy). The recent Food and Drug Administration (FDA) draft drug interaction guidance (http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/ucm072101.pdf) highlights the methodologies and criteria that may be used to guide drug interaction evaluation by industry and regulatory agencies and to construct informative labeling for health practitioner and patients. In addition, the Food and Drug Administration established a "Drug Development and Drug Interactions" website to provide up-to-date information regarding evaluation of drug interactions (http://www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/DrugInteractionsLabeling/ucm080499.htm). This review summarizes key elements in the FDA drug interaction guidance and new scientific developments that can guide the evaluation of drug-drug interactions during the drug development process.

Objective: To investigate the influence of maternal glycemia on fetal heart rate (FHR) parameters analyzed by computerized cardiotocography in fetuses of diabetic mothers in the third trimester., Study Design: Thirty-nine pregnant women with pregestational diabetes mellitus were studied prospectively. The inclusion criteria were a diagnosis of pregestational diabetes, singleton pregnancy between 36 and 40 weeks, and absence of fetal abnormalities. Computerized cardiotocography (System 8002) was performed over a period of 60 min and capillary glycemia was measured immediately before and 30 and 60 min after the beginning of the exam. The evaluations were done 2 h after lunch., Results: Nineteen patients (48.7%) presented mean glycemia > or =120 mg/dL. The mean basal FHR was 136.7+/-10.0 bpm in the group with glycemia <120 mg/dL and 144.8+/-9.4 bpm in the group with glycemia > or =120 mg/dL (p=0.013, Student's t test). There was a significant positive correlation (Pearson's test, p=0.0001, r=0.57) between basal FHR and mean glycemia. A significant negative correlation was observed between short-term variation and mean glycemia (Pearson's test, p=0.003, r=-0.47). No significant differences were observed between the other indices evaluated by computerized cardiotocography and glycemia., Conclusions: Maternal hyperglycemia at the time of cardiotocography is associated with elevated FHR. It seems to be important to understand how FHR parameters are influenced by maternal glycemic status at the time of fetal assessment in pregnancies complicated by diabetes.

1. Pharmacokinetic drug interactions can lead to serious adverse events and the evaluation of a new molecular entity's (NME) drug-drug interaction potential is an integral part of drug development and regulatory review before its market approval. Clinically relevant interactions mediated by transporters are of increasing interest in clinical development and research in this emerging area and it has been revealed that drug transporters can play an important role in modulating drug absorption, distribution, metabolism and elimination. 2. Acting alone or in concert with drug-metabolizing enzymes transporters can affect the pharmacokinetics and/or pharmacodynamics of a drug. The newly released drug interaction guidance by the US Food and Drug Administration (USFDA) includes new information addressing drug transporter interactions with a primary focus on P-glycoprotein (P-gp, ABCB1). 3. This paper provides a regulatory viewpoint on transporters and their potential role in drug-drug interactions. It first outlines information that might be needed during drug development and ultimately included in new drug application (NDA) submissions to address potential transporter-mediated drug interactions. Next, it explains criteria that may warrant conduct of in vivo P-gp-mediated drug interaction studies based on in vitro assessment. In addition, it includes a review case that describes the evaluation of data suggesting a P-gp-based induction interaction.

Predicting clinically significant drug interactions during drug development is a challenge for the pharmaceutical industry and regulatory agencies. Since the publication of the US Food and Drug Administration's (FDA's) first in vitro and in vivo drug interaction guidance documents in 1997 and 1999, researchers and clinicians have gained a better understanding of drug interactions. This knowledge has enabled the FDA and the industry to progress and begin to overcome these challenges. The FDA has continued its efforts to evaluate methodologies to study drug interactions and communicate recommendations regarding the conduct of drug interaction studies, particularly for CYP-based and transporter-based drug interactions, to the pharmaceutical industry. A drug interaction Web site was established to document the FDA's current understanding of drug interactions (http://www.fda.gov/cder/drug/drugInteractions/default.htm). This report provides an overview of the evolution of the drug interaction guidances, includes a synopsis of the steps taken by the FDA to revise the original drug interaction guidance documents, and summarizes and highlights updated sections in the current guidance document, Drug Interaction Studies-Study Design, Data Analysis, and Implications for Dosing and Labeling.

Purpose of Review: To provide a regulatory perspective on the role of drug interaction information in the development of antiretroviral drugs. Additionally, this review highlights novel studies that provided important information for the safe and effective use of antiretroviral medications. The management of drug interactions in HIV therapy becomes more complex with the introduction of each new drug because many antiretroviral drugs are involved in multiple metabolic and transporter-based interactions. Therefore, a comprehensive preclinical evaluation to characterize a new drug's metabolic pathway(s) followed by in-vivo studies is critical for the safe use of combination antiretroviral therapy., Recent Findings: This review highlights published studies to illustrate several clinical and regulatory issues for in-vivo drug interaction studies such as general design issues, study-population selection, study-design options, use of historical controls and interpretation of results., Summary: Early identification of potential drug interactions can help identify and prioritize clinically important interaction studies essential to the overall development process. Understanding the clinical implications and management of drug interactions can lead to more effective long-term therapy, reduce toxicity, and delay the development of resistance.

One of the numerous regulatory functions of the Food and Drug Administration (FDA) is the evaluation of drug-drug interactions and the determination of appropriate dose adjustments, if necessary, to ensure the safe and effective use of medications. The FDA considers several data sources when determining the significance of drug-drug interactions. The majority of dose adjustment recommendations are based on specific drug-drug interactions studies. The FDA reviews individual patient pharmacokinetic and safety data from drug interaction studies, determines appropriate dose adjustments, and provides recommendations to update the respective product labeling. Sometimes literature references are submitted to the FDA to support dosing recommendations. Determining an appropriate dose adjustment recommendation based on literature reports is a challenge for the FDA due to the lack of individual patient pharmacokinetic or safety data from these studies. Recently, the FDA encountered a challenging regulatory situation when evaluating literature reports to determine the appropriate dose of efavirenz and rifampin. Although numerous studies were found in the literature about this combination, a dosing recommendation cannot be concluded from the reported data. This article reviews the process the FDA used to evaluate literature to support potential dose adjustments for efavirenz when coadministered with rifampin and the challenges encountered during the process.

This study tests the association between residents' cognitive impairment and nursing homes' pain management practices. We used chart abstraction to collect data on 551 adults in six North Carolina nursing homes. From the standard data collected in the Minimum Data Set, 24% of residents experienced pain in the preceding week. Reports of pain decreased as cognitive abilities declined: nurses completing the Minimum Data Set reported pain prevalence of 34%, 31%, 24%, and 10%, respectively, for residents with no, mild, moderate, and severe cognitive impairment (P<0.001), demonstrating a "dose-response"-type result. Eighty percent of cognitively intact residents received pain medications, compared to 56% of residents with severe impairment (P<0.001). Cognitively impaired residents had fewer orders for scheduled pain medications than did their less cognitively impaired peers. Yet the presence of diagnoses likely to cause pain did not vary based on residents' cognitive status. We conclude that pain is underrecognized in nursing home residents with cognitive impairment and that cognitively impaired residents often have orders for "as needed" analgesics when scheduled medications would be more appropriate.

Implementing an information technology system can impact more than just quality of care and patient outcomes. The purpose of this 4-year, observational research project is to examine changes in organizational culture, quality improvement (QI) maturity, and quality of care following adoption of a single, electronic health record (EHR) system within an integrated healthcare network. The primary outcome measure, the Culture and Quality Questionnaire (CQQ), assesses the perceived culture of an organization and the degree of CQI maturity in seven quality management areas. Baseline surveys were distributed prior to conversion to the EHR. Subsequent data collection occurred at 12 months post "go live" and will occur at 24 and 36 months after the first hospital "go live". Secondary data were abstracted from routinely collected patient satisfaction measures and standard quality indicators. Contrary to expectation, our findings from the Baseline and 12-month follow-up data suggest that employees perceived the organizational culture as becoming more, rather than less, hierarchical. We also hypothesized that quality indicators would show improvement due to enhanced information flow and ease of information retrieval. This hypothesis was not supported by 1-year results. However, follow-up data from years two and three may provide different results.

The objective of this study was to test whether a quality improvement intervention can improve pain management in nursing homes. Experts in quality improvement and clinical pain management provided nursing home staff leaders with feedback on pain quality indicator data, education in pain management, and technical assistance to apply the Plan-Do-Study-Act model of quality improvement. Trained abstractors completed structured chart audits at baseline and five months to capture quality indicator data related to pain assessment and treatment. Residents in pain who underwent pain assessments increased from 8% to 29% (P < 0.001). Residents receiving non-pharmacological pain treatments increased from 31% to 42% (P = 0.010), but pain medication use did not change. Among residents with daily moderate or excruciating pain, complete pain assessment was associated with increased probability of pain medication use. Quality improvement is a promising method to improve pain management in nursing homes.

Context: Death is common in nursing homes, but access to palliative care is limited., Objective: To test whether a quality improvement (QI) intervention in nursing homes increases hospice, pain management, and advance care planning., Design and Setting: The QI intervention was tested in seven nursing homes using a prepoststudy design. Two additional nursing homes served as control sites., Participants: Nine nursing homes serving 1169 residents., Intervention: The intervention included recruitment and training of Palliative Care Leadership Teams in each facility, followed by six technical assistance meetings for team members. Hospice providers delivered six educational sessions for all nursing home staff using a structured curriculum. Teams received feedback of performance data on hospice enrollment, pain management, and advance care planning at 0, 3, and 6 months., Main Outcome Measures: Percentage of residents receiving hospice or palliative services, pain assessment, pain treatment among residents in pain, and documented advance care planning discussions., Results: Intervention facilities increased hospice enrollment from 4.0% of residents at baseline to 6.8% postintervention (p = .01) and increased pain assessments from 18% to 60% (p < .001). Among resident in pain, orders for nonpharmacologic pain treatments increased from 15% to 35% (p < .001), but pain medication use did not change. Residents with in-depth discussions about end-of-life care increased from 4% to 17% (p < .001). There were no significant changes in control sites., Conclusions: A quality improvement intervention was effective in increasing hospice enrollment, pain assessment, nonpharmacologic pain treatment, and advance care planning discussions.

Background: Enthusiasm for the concept of care management (CM) has led to unprecedented growth in the number of guidelines and protocols, but provider organizations have struggled to enlist the active support and participation of physicians in CM activities., Objectives: To empirically examine the factors influencing physician participation in and attitudes toward CM activities., Methods: Data on 1,514 physicians were used to predict physician attitudes toward CM and their perceptions of group CM behaviors. Dependent variables were modeled using two-stage Heckman selection bias models with fixed effects corrections. Independent predictors included physician- and group-level controls as well as six potential CM participation and attitude facilitators., Results: Physician participation in the implementation phase of CM activities was positively related to participation and attitude. However, physician participation in the development phase may be negatively related to later participation in CM activities. Management involvement in development phase has mixed effects (positive or no effect), but their involvement in the implementation phase was somewhat negatively related to CM participation and attitude. Financial incentives for participation in CM activities and presence of a useful management information system also appeared to be positively related to attitude and participation., Conclusions: Appropriate physician and management involvement, as well as financial incentives and useful management information systems may facilitate physician participation in CM activities. Physician involvement in implementation of CM practices appears to be important, whereas their involvement in the development phase may be negatively related to later attitudes and participation. The findings call for a more in-depth understanding of the timing of physician input in CM activities.

A rapid PCR method was developed using the Roche LightCycler technology for detection of Herpes Simplex Virus I and II. The Lightcycler method was compared with tissue culture and direct HSV antigen detection using routine clinical samples. The LightCycler PCR was shown to be more sensitive than isolation by tissue culture (sensitivity of culture versus PCR 78%) and HSV antigen detection (sensitivity of EIA versus PCR 56%). The amplified product may be typed without additional tests. The LightCycler PCR method provides a rapid method for HSV detection that correlates well with established tests.

Objectives: To assess the impact of total quality management (TQM) and organizational culture on a comprehensive set of endpoints of care for coronary artery bypass graft surgery (CABG) patients, including risk-adjusted adverse outcomes, clinical efficiency, patient satisfaction, functional health status, and cost of care., Methods: Prospective cohort study of 3,045 eligible CABG patients from 16 hospitals using risk-adjusted clinical outcomes, functional health status, patient satisfaction, and cost measures. Implementation of TQM was measured by a previously validated instrument based on the Baldridge national quality award criteria. Organizational culture was measured by a previously validated 20-item instrument. Generalized estimating equations were used to control for potential selection bias, repeated measures, and intraclass correlation., Results: A 2- to 4-fold difference in all major clinical CABG care endpoints was observed among the 16 hospitals, but little of this variation was associated with TQM or organizational culture. Patients receiving CABG from hospitals with high TQM scores were more satisfied with their nursing care (P = 0.005) but were more likely to have lengths of stay >10 days (P = 0.0003). A supportive group culture was associated with shorter postoperative intubation times (P = 0.01) but longer operating room times (P = 0.004). A supportive group culture was also associated with higher patient physical (P = 0.005) and mental (P = 0.01) functional health status scores 6 months after CABG., Conclusions: There was little effect of TQM and organizational culture on multiple endpoints of care for CABG patients. There is a need to examine further the relationships among individual professional skills and motivations, group and microsystem team processes, specifically tailored interventions, and organization-wide culture, decision support processes, and incentives. Assessing the impact of such multifaceted approaches is an important area for further research.

Background: Virtually all hospitals in the United States report that they engage in efforts to improve quality, such as continuous quality improvement (CQI). Little is known about the costs of these efforts and whether they are associated with improved outcomes or lower patient-care costs., Objectives: The principal objective of this study was to provide benchmark data on the costs of efforts to improve quality. The authors also attempted to determine if quality improvement expenditures are correlated with outcomes and/or condition-specific hospital costs., Methods: Detailed information on the cost of quality improvement was obtained from hospitals participating in a broad study of CQI activities. These data were correlated with patient outcomes and condition-specific costs. The subjects were medium to large hospitals throughout the United States. Senior managers provided budgetary information on direct costs of quality improvement, and details about meetings associated with quality improvement. They also provided summary medical bills for all patients undergoing total hip replacement and coronary artery bypass graft surgery. The billing information was combined with data provided by the Health Care Finance Administration to estimate condition-specific costs. Patients were directly surveyed to obtain information about satisfaction and outcomes., Results: There is a wide range of expenditures on quality improvement activities. Meeting costs are a substantial percentage of total costs. Neither total costs nor meeting costs are correlated with condition-specific costs., Discussion: Hospital managers can be expected to insist on evidence that quality improvement expenditures produce tangible benefits. This article provides benchmark estimates of those benefits and a methodology for further research.