Predictors of Systemic Exposure to Topical Crisaborole: A Nonlinear Regression Analysis

Crisaborole ointment, 2%, is a nonsteroidal phosphodiesterase 4 inhibitor for the treatment of mild to moderate atopic dermatitis. Results from 2 randomized, double-blind, vehicle-controlled phase 3 studies showed that twice-daily crisaborole in children and adults with mild to moderate atopic dermatitis was efficacious and well tolerated. Initial pharmacokinetics (PK) studies of crisaborole indicated absorption with measurable systemic levels of crisaborole. The current analysis was conducted to correlate steady-state systemic exposure parameters with ointment dose and identify covariates impacting PK parameters in healthy participants and patients with atopic dermatitis or psoriasis. A nonlinear regression analysis was conducted using ointment dose and noncompartmental PK parameters at steady state (area under the curve [AUC_ss ] and maximum concentration [C_max,ss ]). PK data were available from 244 participants across 6 clinical studies (AUC_ss , N = 239; C_max,ss , N = 241). Disease condition had the greatest impact on slope in both models, corresponding to 2.5-fold higher AUC_ss and C_max,ss values at a given ointment dose in patients with atopic dermatitis or psoriasis relative to healthy participants. Disease severity, race/ethnicity, and sex had marginal effects on AUC_ss and C_max,ss . Systemic exposures were similar across age groups ≥2 years of age when the same percentage of body surface area (%BSA) was treated. Predictive performance plots for AUC_ss and C_max,ss for different age groups demonstrated that the models adequately describe the observed data. Model predictions indicated that systemic exposure to crisaborole in pediatric patients (2-17 years) is unlikely to exceed systemic exposure in adults (≥18 years), even at the highest possible ointment dose corresponding to a %BSA of 90.

Dose-proportional pharmacokinetic properties of GLA5PR GLARS-NF1 controlled-release pregabalin in healthy Korean volunteers: a randomized, open, single-dose, parallel study

Purpose

The aim of this study was to evaluate the dose-proportional pharmacokinetic characteristics of pregabalin following the administration of GLA5PR GLARS-NF1 tablets (150, 300, 450, and 600 mg) in the fed state.

Subjects and methods

An open-label, randomized, single-dose, parallel study was conducted in 40 eligible subjects who were randomly assigned to receive a single 150, 300, 450, or 600 mg dose of GLA5PR GLARS-NF1. Serial blood samples were collected before and after dosing for 36 hours, and plasma concentrations were determined using liquid chromatography-tandem mass spectrometry. Safety profiles were evaluated throughout the study (trial registration number: NCT02327000).

Results

Thirty-seven subjects completed the studies. The area under the plasma concentration-time curve up to the last measurable concentration of pregabalin exhibited dose proportionality following administration of GLA5PR GLARS-NF1 tablets from 150 to 600 mg while its maximum plasma concentration showed dose proportionality at a dose range of 150–450 mg. The safety evaluations showed no clinically significant finding after administration of GLA5PR GLARS-NF1 tablets (150, 300, 450, and 600 mg) in the fed state.

Conclusions

The dose-proportional properties of GLA5PR GLARS-NF1 150–450 mg tablets were determined.

Evaluation of the Adequacy of the 2010 Revised World Health Organization Recommended Dosages of the First-line Antituberculosis Drugs for Children: Adequacy of Revised Dosages of TB Drugs for Children

BACKGROUND

The World Health Organization recommended increased dosages of the first-line antituberculosis (anti-TB) drugs for children in 2010. We examined the frequency of and factors associated with low plasma maximum concentration (Cmax) of each drug in children treated with the revised dosages.

METHODS

Children on anti-TB therapy for at least 4 weeks underwent pharmacokinetic testing. Plasma Cmax below the lower limit of proposed reference range was considered low. Bivariate and multivariate analyses were used to examine the factors associated with low Cmax of each drug.

RESULTS

Of the 100 children, 58% were male, 50% HIV-infected and 49% younger than 5 years old. The median (interquartile range) Cmax was 5.9 (4.5-7.7) µg/mL for isoniazid, 6.5 (4.9-8.8) µg/mL for rifampin, 26.0 (21.2-33.4) µg/mL for pyrazinamide and 1.7 (0.9-2.7) µg/mL for ethambutol. There was a strong correlation between Cmax and AUC0-8h for all drugs. Low Cmax occurred in 9/100 (9.0%), 61/100 (61.0%), 17/97 (17.5%) and 60/97 (61.9%) for isoniazid, rifampin, pyrazinamide and ethambutol, respectively. In addition, 75/97 (77.3%) children had pyrazinamide Cmax < 35 µg/mL. Factors associated with low Cmax were NAT2 metabolizer phenotype status for isoniazid; height, dosage and HIV coinfection status for rifampin; height for pyrazinamide; and age, dosage and HIV coinfection status for ethambutol.

CONCLUSIONS

The high frequency of low rifampin and ethambutol Cmax in our study is consistent with emerging pharmacokinetic data in children treated according to the new WHO recommendations. Higher dosages than currently recommended especially for rifampin may be necessary in children.

Brain and peripheral pharmacokinetics of levodopa in the cynomolgus monkey following administration of opicapone, a third generation nitrocatechol COMT inhibitor

OBJECTIVE

The present study aimed at evaluating the effect of opicapone, a third generation nitrocatechol catechol-O-methyltransferase (COMT) inhibitor, on the systemic and central bioavailability of 3,4-dihydroxy-l-phenylalanine (levodopa) and related metabolites in the cynomolgus monkey.

METHODS

Four monkeys, implanted with guiding cannulas for microdialysis probes, in the substantia nigra, dorsal striatum and prefrontal cortex, were randomized in two groups that received, in a crossover design, vehicle or 100 mg/kg opicapone for 14 days. Twenty-three hours after last administration of vehicle or opicapone, animals were challenged with levodopa/benserazide (12/3 mg/kg). Extracellular dialysate and blood samples were collected over 360 min (at 30 min intervals) for the assays of catecholamine and COMT activity.

RESULTS

Opicapone increased levodopa systemic exposure by 2-fold not changing Cmax values and reduced both 3-O-methyldopa (3-OMD) exposure and Cmax values by 5-fold. These changes were accompanied by ∼76-84% reduction in erythrocyte COMT activity. In dorsal striatum and substantia nigra, opicapone increased levodopa exposure by 1.7- and 1.4-fold, respectively, reducing 3-OMD exposure by 5- and 7-fold respectively. DOPAC exposure was increased by 4-fold in the substantia nigra. In the prefrontal cortex, opicapone increased levodopa exposure and reduced 3-OMD levels by 2.3- and 2.4-fold, respectively.

CONCLUSIONS

Opicapone behaved as long-acting COMT inhibitor that markedly increased systemic and central levodopa bioavailability. Opicapone is a strong candidate to fill the unmet need for COMT inhibitors that lead to more sustained levodopa levels in Parkinson's disease patients.

Greater impairment of postprandial triacylglycerol than glucose response in metabolic syndrome subjects with fasting hyperglycaemia

OBJECTIVE

Studies have started to question whether a specific component or combinations of metabolic syndrome (MetS) components may be more important in relation to cardiovascular disease risk. Our aim was to examine the impact of the presence of raised fasting glucose as a MetS component on postprandial lipaemia.

METHODS

Men classified with the MetS underwent a sequential test meal investigation, in which blood samples were taken at regular intervals after a test breakfast (t=0 min) and lunch (t=330 min). Lipids, glucose and insulin were measured in the fasting and postprandial samples.

RESULTS

MetS subjects with 3 or 4 components were subdivided into those without (n=34) and with (n=23) fasting hyperglycaemia (≥5.6 mmol/l), irrespective of the combination of components. Fasting lipids and insulin were similar in the two groups, with glucose significantly higher in the men with glucose as a MetS component (P<0.001). Following the test meals, there were higher maximum concentration (maxC), area under the curve (AUC) and incremental AUC (P ≤0.016) for the postprandial triacylglycerol (TAG) response in men with fasting hyperglycaemia. Greater glucose AUC (P<0.001) and insulin maxC (P=0.010) were also observed in these individuals after the test meals. Multiple regression analysis revealed fasting glucose to be an important predictor of the postprandial TAG and glucose response.

CONCLUSION

Our data analysis has revealed a greater impairment of postprandial TAG than glucose response in MetS subjects with raised fasting glucose. The worsening of postprandial lipaemic control may contribute to the greater CVD risk reported in individuals with MetS component combinations which include hyperglycaemia.

Systemic in vitro and in vivo evaluation for determining the feasibility of making an amorphous solid dispersion of a B-Raf (rapidly accelerated fibrosarcoma) inhibitor

It is well acknowledged that oral bioavailability of a drug candidate is often influenced by factors such as the permeability, physico-chemical properties, and metabolism of the drug. Among the physico-chemical properties, solubility and dissolution rate are considered the most critical factors affecting the oral bioavailability of a compound G-F is a potent and selective B-Raf inhibitor with poor solubility and adsorption is limited by solubility at high doses. In order to overcome this issue using a spray-dried amorphous dispersion (SDD) formulation was evaluated. A combination of theoretical solubility prediction and in vitro dissolution, were used to predict the in vivo exposure of G-F. The predicted value was found to have good agreement with the in vivo exposure from dosing the crystalline and amorphous form of G-F. In general, this combined approach demonstrated that the amorphous form of G-F offers an advantage over the crystalline form of G-F in terms of solubility; in vitro dissolution and in vivo absorption were predictable and consistent with the literature. This systemic approach provides a great value for compound development.

Preclinical efficacy and safety of rVIII-SingleChain (CSL627), a novel recombinant single-chain factor VIII

INTRODUCTION

The preclinical efficacy and safety of rVIII-SingleChain (CSL627), a novel recombinant single-chain factor VIII, was assessed in a series of animal studies.

MATERIALS AND METHODS

In the tail-clip bleeding model, hemophilia A mice were injected with escalating doses (1-150 IU/kg) of rVIII-SingleChain, B-domain deleted (BDD) rFVIII (ReFacto AF(®)), or full-length rFVIII products (Advate(®), Helixate(®)). Total blood loss and the percentage of animals in which hemostasis occurred were assessed in this observer-blinded, randomized study. In a second non-randomized study in hemophilia A mice, thromboelastographic analysis, thrombin generation, and activated partial thromboplastin time assays were performed. General safety and toxicity were assessed in three animal species, including determination of the prothrombotic potential of rVIII-SingleChain in a rabbit venous thrombosis model.

RESULTS

Under acute bleeding conditions, the effect of rVIII-SingleChain on total blood loss and hemostasis was indistinguishable from BDD and full-length rFVIII. rVIII-SingleChain and full-length rFVIII (both 20 IU/kg) corrected thromboelastographic parameters, activated partial thromboplastin time, and thrombin generation to a similar degree in hemophilia A mice. In a thrombosis model, the effect of rVIII-SingleChain on thrombus incidence was non-significant and comparable to BDD rFVIII at doses up to 500 IU/kg. Treatment with rVIII-SingleChain did not cause anaphylactic reaction or local intolerance in safety and toxicity studies, and demonstrated an excellent overall safety profile.

CONCLUSIONS

rVIII-SingleChain showed convincing hemostatic efficacy and excellent tolerability in animal studies, warranting continued investigation in human Phase I/III trials (AFFINITY).

Characterization of vaniprevir, a hepatitis C virus NS3/4A protease inhibitor, in patients with HCV genotype 1 infection: safety, antiviral activity, resistance, and pharmacokinetics

Vaniprevir is a competitive inhibitor of the hepatitis C virus (HCV) NS3/4A protease that has potent anti-HCV activity in preclinical models. This placebo-controlled dose-ranging study assessed the safety, tolerability, and antiviral efficacy of vaniprevir monotherapy in patients with genotype 1 chronic HCV infection. Treatment-naive and treatment-experienced non-cirrhotic adult patients with baseline HCV RNA >10(6)IU/ml were randomized to receive placebo or vaniprevir at doses of 125 mg qd, 600 mg qd, 25mg bid, 75 mg bid, 250 mg bid, 500 mg bid, and 700 mg bid for 8 days. Forty patients (82.5% male, 75% genotype 1a) received at least one dose of placebo or vaniprevir. After 1 week of vaniprevir, the decrease in HCV RNA from baseline ranged from 1.8 to 4.6 log₁₀IU/ml across all treatment groups, and there was a greater than dose-proportional increase in vaniprevir exposure at doses above 75 mg bid. The most commonly reported drug-related adverse events (AEs) were diarrhea (n=5) and nausea (n=5). No pattern of laboratory or ECG abnormalities was observed, all AEs resolved during the study, and there were no discontinuations due to AEs. No serious AEs were reported. Resistance-associated amino acid variants were identified at positions R155 and D168 in patients infected with genotype 1a virus. Vaniprevir monotherapy demonstrated potent antiviral activity in patients with chronic genotype 1 HCV infection, and was generally well tolerated with no serious AEs or discontinuations due to AEs. Further development of vaniprevir, including studies in combination with other anti-HCV agents, is ongoing.