Midazolam Limited Sampling Strategy With a Population Pharmacokinetic Approach to Simultaneously Estimate Cytochrome P450 (CYP) 3A Constitutive, Inhibition, and Induction/Activation Conditions in Healthy Adults.

We have previously described a midazolam limited sampling strategy employing a population pharmacokinetic (PK) approach to estimate constitutive cytochrome P450 (CYP) 3A activity. This study evaluated expansion of this approach to estimate CYP3A constitutive, inhibitory, and induction activities. Midazolam concentrations (n = 4441) from adults (n = 152) were obtained from previous studies after single, oral, or intravenous administration with intensive sample collection.

Midazolam Single Time Point Concentrations to Estimate Exposure and Cytochrome P450 (CYP) 3A Constitutive Activity Utilizing Limited Sampling Strategy With a Population Pharmacokinetic Approach.

Midazolam is the preferred probe to phenotype cytochrome P450 (CYP) 3A activity. This study evaluated a single-concentration, midazolam limited sampling strategy utilizing a population pharmacokinetic (PK) approach to estimate area under the curve, and thus CYP3A activity. Midazolam concentrations from adults during CYP3A constitutive conditions were obtained from previous studies after single, oral or intravenous administration.

A call to incorporate systems theory and human factors into the existing investigation of harm in clinical research involving healthcare products.

This is a joint statement from individual pharmacology and pharmaceutical professionals acting in their own capacity, including members of the Alliance for Clinical Research Excellence and Safety (ACRES) and the International Society of Pharmacovigilance (ISoP). By building on the extensive pharmacological and regulatory investigations that already take place, we are calling for a fuller and more robust systems-based approach to the independent investigation of clinical research when serious incidents of harm occur, starting with first-in-human clinical trials. To complement existing activities and regulations, we propose an additional approach blending evidence derived from both pharmacological and organizational science, which addresses human factors and transparency, to enhance organizational learning and continuous improvement.

Comprehensive review of visual defects reported with topiramate.

Objective: The objective of this study was to analyze clinical patterns of visual field defects (VFDs) reported with topiramate treatment and assess possible mechanism of action (MOA) for antiepileptic drug (AED) associated VFDs.

Methods: A comprehensive topiramate database review included preclinical data, sponsor's clinical trials database, postmarketing spontaneous reports, and medical literature. All treatment-emergent adverse events (TEAEs) suggestive of retinal dysfunction/damage were summarized.

Structured Risk Assessment for First-in-Human Studies.

We describe a structured risk assessment and risk mitigation process that is currently used to evaluate proposed first-in human (FiH) studies. This process balances the inherent risks of an FiH study with maximal protection of subjects. Risk assessment should consider all available data, carefully identifying aspects that may lead to risk for healthy subjects.

Safety in FIH Trials: A Summary of the Symposium "Fatal Drug Trial in Phase 1: Understanding Risk, Subject Safety, Timelines, and Cost".

A cross-section of clinical research professionals convened at the June 2016 Drug Information Association annual meeting in Philadelphia to discuss and critically analyze the first-in-human (FIH) clinical trial conducted by a French CRO with BIA 10-2474 (BIA) under development for pain relief by Bial-Portela & Ca., S.A.

Hot Button Protocol and Operational Issues Between Sponsors and Sites in Clinical Pharmacology Studies: A Moderated Forum Session.

This paper summarizes a discussion that took place at the 52nd Annual DIA Meeting in Philadelphia, PA, on June 30, 2016, titled "Hot-Button Protocol and Operational Issues between Sponsors and Sites in Clinical Pharmacology Studies." The symposium was a moderated panel of phase 1 clinical research experts representing the sponsor, and investigational sites. Conference attendees of similar experience joined in the discussion after commentary by each panelist.

Is uveitis associated with topiramate use? A cumulative review.

Occasional reports of uveitis following topiramate use necessitated an investigation of relevant cases from safety databases and published biomedical literature. Data mining of the Food and Drug Administration Adverse Event Reporting System and cumulative review of cases from the global safety database (sponsor database) and published literature were conducted to assess association between topiramate use and uveitis. The Food and Drug Administration Adverse Event Reporting System search identified disproportional reporting of uveitis (n=23) and related terms (choroidal detachment, n=25; iridocyclitis, n=17).

Inhibition of prostacyclin and thromboxane biosynthesis in healthy volunteers by single and multiple doses of acetaminophen and indomethacin.

This double-blind, randomized crossover study assessed the effect of acetaminophen (1000 mg every 8 hours) versus indomethacin (50 mg every 8 hours) versus placebo on cyclooxygenase enzymes (COX-1 and COX-2). Urinary excretion of 2,3-dinor-6-keto-PGF1α, (prostacyclin metabolite, PGI-M; COX-2 inhibition) and 11-dehydro thromboxane B2 (thromboxane metabolite, Tx-M; COX-1 inhibition) were measured after 1 dose and 5 days of dosing. Peak inhibition of urinary metabolite excretion across 8 hours following dosing was the primary end point.

Investigators' Experience With Expedited Safety Reports Prior to the FDA's Final IND Safety Reporting Rule.

Prior to enactment of the final investigational new drug application (IND) safety reporting rule, an attempt was made to document the effort expended at investigative sites in processing IND safety reports from sponsors and to assess the effect of these expedited reports on trial conduct. Investigators were asked to (1) prospectively document time to process IND safety reports and (2) retrospectively review safety reports from a previous 3-month period, documenting resultant actions. In this limited sample, sites spent a median of 0.

Limited sampling strategy of partial area under the concentration-time curves to estimate midazolam systemic clearance for cytochrome P450 3A phenotyping.

Objective: Intravenous (IV) midazolam is the preferred cytochrome P450 (CYP) 3A probe for phenotyping, with systemic clearance (CL) estimating hepatic CYP3A activity. A limited sampling strategy was conducted to determine whether partial area under the concentration-time curves (AUCs) could reliably estimate midazolam systemic CL during conditions of CYP3A baseline activity, inhibition, and induction/activation.

Methods: Midazolam plasma concentrations during CYP3A baseline (n = 93), inhibition (n = 40), and induction/activation (n = 33) were obtained from 7 studies in healthy adults.

MK-0448, a specific Kv1.5 inhibitor: safety, pharmacokinetics, and pharmacodynamic electrophysiology in experimental animal models and humans.

Background: We evaluated the viability of I(Kur) as a target for maintenance of sinus rhythm in patients with a history of atrial fibrillation through the testing of MK-0448, a novel I(Kur) inhibitor.

Methods And Results: In vitro MK-0448 studies demonstrated strong inhibition of I(Kur) with minimal off-target activity. In vivo MK-0448 studies in normal anesthetized dogs demonstrated significant prolongation of the atrial refractory period compared with vehicle controls without affecting the ventricular refractory period.

Safety and immunogenicity of a novel Staphylococcus aureus vaccine: results from the first study of the vaccine dose range in humans.

Merck V710 is a novel vaccine containing the conserved Staphylococcus aureus iron surface determinant B shown to be protective in animal models. A phase I, multicenter, double-blind study of the dose range was conducted to assess the immunogenicity and safety of an adjuvanted liquid formulation of V710. A total of 124 adults (18 to 55 years of age) were randomized 1:1:1:1 to receive one 0.

Double-blind crossover study to assess potential differences in cytochrome P450 3A4 activity in healthy subjects receiving ondansetron plus dexamethasone, with and without aprepitant.

Purpose: Because glucocorticoids and the neurokinin-1 receptor antagonist aprepitant influence CYP3A4 activity, this study assessed whether aprepitant added to a 5-HT(3) antagonist and glucocorticoid would affect CYP3A4 induction.

Methods: In this double-blind, 2-period crossover study, 12 subjects were randomized to receive a triple regimen (oral aprepitant [A] 125 mg, intravenous ondansetron [O] 32 mg, and oral dexamethasone [D] 12 mg day 1; A 80 mg and D 8 mg days 2-3; D 8 mg day 4) in 1 of 2 periods, and a dual regimen (O 32 mg and D 20 mg day 1; D 8 mg bid days 2-4); the D dose was adjusted to account for known dexamethasone/aprepitant interaction. Oral (2 mg) and intravenous (1 mg) stable isotope ((13)C(5) (15)N(1))-labeled midazolam were simultaneously given as probes on days -1, 6, 8, 15, and 22 of each period.

Diurnal variation of the human adipose transcriptome and the link to metabolic disease.

Background: Circadian (diurnal) rhythm is an integral part of the physiology of the body; specifically, sleep, feeding behavior and metabolism are tightly linked to the light-dark cycle dictated by earth's rotation.

Methods: The present study examines the effect of diurnal rhythm on gene expression in the subcutaneous adipose tissue of overweight to mildly obese, healthy individuals. In this well-controlled clinical study, adipose biopsies were taken in the morning, afternoon and evening from individuals in three study arms: treatment with the weight loss drug sibutramine/fasted, placebo/fed and placebo/fasted.

Minimal effects of ritonavir and efavirenz on the pharmacokinetics of raltegravir.

Raltegravir is a novel human immunodeficiency virus type 1 (HIV-1) integrase strand transfer inhibitor with potent in vitro activity against HIV-1 (95% inhibitory concentration = 31 nM in 50% human serum). The possible effects of ritonavir and efavirenz on raltegravir pharmacokinetics were separately examined. Two clinical studies of healthy subjects were conducted: for ritonavir plus raltegravir, period 1, 400 mg raltegravir; period 2, 100 mg ritonavir every 12 h for 16 days with 400 mg raltegravir on day 14; for efavirenz plus raltegravir, period 1, 400 mg raltegravir; period 2, 600 mg efavirenz once daily for 14 days with 400 mg raltegravir on day 12.

Effect of aprepitant on the pharmacokinetics of intravenous midazolam.

Oral aprepitant 125 mg, an antiemetic and a moderate inhibitor of the metabolism of oral midazolam, was assessed for interaction with intravenous midazolam in 12 subjects randomized to intravenous midazolam 2 mg +/- oral aprepitant 125 mg. The hypothesis was that midazolam AUC would not change by more than 2-fold (consistent with no more than weak inhibition) when midazolam + aprepitant was compared with midazolam alone. An AUC geometric mean ratio (midazolam + aprepitant/midazolam) with 90% confidence interval upper bound < or =2.

The pharmacokinetics of taurolidine metabolites in healthy volunteers.

Taurolidine is an experimental antibacterial and antiendotoxic compound whose clinical utility as an antitumor agent is being investigated in human clinical trials. Taurolidine in aqueous solution exists in equilibrium with taurultam. Taurultam is subsequently transformed to taurinamide.

Human pharmacokinetics and interconversion of enantiomers of MK-0767, a dual PPARalpha/gamma agonist.

MK-0767, a dual peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist, has been studied as a potential treatment of type 2 diabetes and dyslipidemia. The pharmacokinetics and interconversion of (+)-(R)-MK-0767 and (-)-(S)-MK-0767 were evaluated following oral administration of each single enantiomer and the racemate to healthy subjects. The results demonstrate that, consistent with in vitro experiments, chiral inversion occurs rapidly in vivo, and interconversion equilibrium favors (+)-(R).

Effects of ezetimibe on cyclosporine pharmacokinetics in healthy subjects.

This single-center, open-label, 2-period crossover study investigated the effects of multiple-dose ezetimibe (EZE) on a single dose of cyclosporine (CyA). Healthy subjects received 2 treatments in random order with a 14-day washout: (1) CyA 100 mg alone and (2) EZE 20 mg for 7 days with CyA 100 mg coadministered on day 7; EZE 20 mg alone was administered on day 8. AUC(0-last) and Cmax geometric mean ratios (90% confidence interval) for ([CyA + EZE]/CyA alone) were 1.

Pharmacokinetics of aprepitant after single and multiple oral doses in healthy volunteers.

Aprepitant is the first NK1 receptor antagonist approved for use with corticosteroids and 5HT3 receptor antagonists to prevent chemotherapy-induced nausea and vomiting (CINV). The effective dose to prevent CINV is a 125-mg capsule on day 1 followed by an 80-mg capsule on days 2 and 3. Study 1 evaluated the bioavailability of the capsules and estimated the effect of food.

The effects of modifying in vivo cytochrome P450 3A (CYP3A) activity on etoricoxib pharmacokinetics and of etoricoxib administration on CYP3A activity.

To investigate the influence of modifying in vivo cytochrome P450 3A (CYP3A) activity on the pharmacokinetics of etoricoxib, a selective inhibitor of cyclooxygenase-2, and of etoricoxib administration on CYP3A activity, a 3-part, randomized, crossover study was conducted in 3 panels of healthy volunteers. In part I, 8 subjects were administered a single dose of 60 mg etoricoxib alone and following daily doses of 400 mg ketoconazole, a known strong inhibitor of CYP3A. In part II, 8 different subjects were administered a single dose of 60 mg etoricoxib alone and following daily doses of 600 mg rifampin, a known strong inducer of CYP3A.

Indinavir and rifabutin drug interactions in healthy volunteers.

Two studies examined the pharmacokinetics of indinavir and rifabutin when coadministered in healthy subjects. Rifabutin, which induces the expression of cytochrome P450 (CYP) 3A, and indinavir, which inhibits that enzyme system, are frequently coadministered in patients infected with HIV. The second study was undertaken to determine if altering the dose of rifabutin coadministered with indinavir would minimize the drug interaction observed in the first study.