Evaluation of the administration time effect on the cumulative cortisol suppression and cumulative lymphocytes suppression for once-daily inhaled corticosteroids: a population modeling/simulation approach

Assessment of the predictive capability of modelling and simulation to determine bioequivalence of inhaled drugs: A systematic review

OBJECTIVES

There are a multitude of different modelling techniques that have been used for inhaled drugs. The main objective of this review was to conduct an exhaustive survey of published mathematical models in the area of asthma and chronic obstructive pulmonary disease (COPD) for inhalation drugs. Additionally, this review will attempt to assess the applicability of these models to assess bioequivalence (BE) of orally inhaled products (OIPs).

EVIDENCE ACQUISITION

PubMed, Science Direct, Web of Science, and Scopus databases were searched from 1996 to 2020, to find studies that described mathematical models used for inhaled drugs in asthma/COPD.

RESULTS

50 articles were finally included in this systematic review. This research identified 22 articles on in silico aerosol deposition models, 20 articles related to population pharmacokinetics and 8 articles on physiologically based pharmacokinetic modelling (PBPK) modelling for inhaled drugs in asthma/COPD. Among all the aerosol deposition models, computational fluid dynamics (CFD) simulations are more likely to predict regional aerosol deposition pattern in human respiratory tracts. Across the population PK articles, body weight, gender, age and smoking status were the most common covariates that were found to be significant. Further, limited published PBPK models reported approximately 29 parameters relevant for absorption and distribution of inhaled drugs. The strengths and weaknesses of each modelling technique has also been reviewed.

CONCLUSION

Overall, while there are different modelling techniques that have been used for inhaled drugs in asthma and COPD, there is very limited application of these models for assessment of bioequivalence of OIPs. This review also provides a ready reference of various parameters that have been considered in various models which will aid in evaluation if one model or hybrid in silico models need to be considered when assessing bioequivalence of OIPs.

Towards a Quantitative Mechanistic Understanding of Localized Pulmonary Tissue Retention-A Combined In Vivo/In Silico Approach Based on Four Model Drugs

Increasing affinity to lung tissue is an important strategy to achieve pulmonary retention and to prolong the duration of effect in the lung. As the lung is a very heterogeneous organ, differences in structure and blood flow may influence local pulmonary disposition. Here, a novel lung preparation technique was employed to investigate regional lung distribution of four drugs (salmeterol, fluticasone propionate, linezolid, and indomethacin) after intravenous administration in rats. A semi-mechanistic model was used to describe the observed drug concentrations in the trachea, bronchi, and the alveolar parenchyma based on tissue specific affinities (Kp) and blood flows. The model-based analysis was able to explain the pulmonary pharmacokinetics (PK) of the two neutral and one basic model drugs, suggesting up to six-fold differences in Kp between trachea and alveolar parenchyma for salmeterol. Applying the same principles, it was not possible to predict the pulmonary PK of indomethacin, indicating that acidic drugs might show different pulmonary PK characteristics. The separate estimates for local Kp, tracheal and bronchial blood flow were reported for the first time. This work highlights the importance of lung physiology- and drug-specific parameters for regional pulmonary tissue retention. Its understanding is key to optimize inhaled drugs for lung diseases.

Exposure-Response and Clinical Outcome Modeling of Inhaled Budesonide/Formoterol Combination in Asthma Patients

Exposure-response and clinical outcome (CO) model for inhaled budesonide/formoterol was developed to quantify the relationship among pharmacokinetics (PK), pharmacodynamics (PD) and CO of the drugs and evaluate the covariate effect on model parameters. Sputum eosinophils cationic proteins (ECP) and forced expiratory volume (FEV1) were selected as PD markers and asthma control score was used as a clinical outcome. One- and two-compartment models were used to describe the PK of budesonide and formoterol, respectively. The indirect response model (IDR) was used to describe the PD effect for ECP and FEV1. In addition, the symptomatic effect on the disease progression model for CO was connected with IDR on each PD response. The slope for the effect of ECP and FEV1 to disease progression were estimated as 0.00008 and 0.644, respectively. Total five covariates (ex. ADRB2 genotype etc.) were searched using a stepwise covariate modeling method, however, there was no significant covariate effect. The results from the simulation study were showed that a 1 puff b.i.d. had a comparable effect of asthma control with a 2 puff b.i.d. As a result, the 1 puff b.i.d. of combination drug could be suggested as a standardized dose to minimize the side effects and obtain desired control of disease compared to the 2 puff b.i.d.

PK/PD modeling of 5-hydroxytryptophan (5-HTP) challenge test with cortisol measurement in serum and saliva

This research was planned to build a Pharmacokinetic/Pharmacodynamic (PK/PD) model of 5‐hydroxytryptophan (5‐HTP) challenge study including a circadian rhythm component of cortisol and to predict serum cortisol based on saliva cortisol. Data from three 5‐HTP challenge studies in healthy volunteers were collected. Serum 5‐HTP, saliva, and serum cortisol were sampled as PK and PD marker. The population PK/PD modeling approach was applied. A baseline model of serum cortisol was built to assess the circadian rhythm before a pharmacodynamic model was used to evaluate the drug effect of the 5‐HTP on cortisol. Finally, linear and power function relationships were tested to predict serum cortisol based on saliva cortisol. The PK of 5‐HTP could be described using a one‐compartment model with a transit compartment. The typical value for clearance was 20.40 L h⁻¹ and showed inter‐study variability. A cosine function was chosen and properly described the circadian rhythm of serum cortisol. A linear approximation model was applied to fit the 5‐HTP PD effect on cortisol data with a slope of 4.16 ng mL⁻¹ h. A power function provided a better description than a linear function to relate the saliva and serum cortisol. In conclusion, a circadian rhythm component was built in the PK/PD model of the 5‐HTP challenge test which could better improve the understanding of the stimulating effect on HPA with cortisol change. After the 5‐HTP challenge, saliva cortisol correlated well with serum cortisol and was predictable by a population PK‐PD model.

Impact of dosage timing of once-daily inhaled corticosteroids in asthma: A systematic review and meta-analysis

BACKGROUND

Once-daily inhaled corticosteroids (ICSs) are widely used as first-line therapy in patients with asthma.

OBJECTIVE

To compare the efficacy of ICSs administered once daily in the morning or evening as determined by lung function.

METHODS

Medline, Embase, and the Cochrane Central Register were searched for relevant clinical trials. The primary outcome was lung function assessed as trough forced expiratory volume in 1 second and peak expiratory flow at end point.

RESULTS

Eight randomized clinical trials involving 1,234 patients were analyzed. The total number of patients treated with once-daily ICS in the morning and evening was 628 and 606, respectively. Pooled estimates showed that ICS administered once daily in the evening resulted in mild improvements in trough forced expiratory volume in 1 second (mean difference 0.05 L; 95% confidence interval 0.01-0.09; P = .026; I² = 22.5%) and morning peak expiratory flow (mean difference 13.92 L/min; 95% confidence interval 5.77-22.06; P = .001; I² = 13%) at end point compared with morning dosing. The change in use of rescue medicine and the incidence of adverse events with once-daily ICS were not significantly different between the 2 dosing times.

CONCLUSION

Compared with morning dosing, ICSs administered once daily in the evening seemed to provide some benefits in lung function for patients with asthma. However, because of methodologic limitations, further large-scale randomized clinical trials for dosing time of once-daily ICSs are needed.

Pharmacokinetics of Budesonide Administered with Surfactant in Premature Lambs: Implications for Neonatal Clinical Trials

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of premature human infants, which may persist through adulthood. Airway inflammation has been firmly established in the pathogenesis of BPD. Previous studies to reduce airway inflammation with high-dose dexamethasone demonstrated adverse neurological outcomes, despite lower incidences of BPD. Instillation of budesonide and surfactant can facilitate early extubation and reduce the incidence of BPD and death among very low birth weight infants. However, the pharmacokinetics of budesonide and its distribution into the lung and brain are unknown. Therefore, 5 premature lambs were administered 0.25 mg/kg budesonide, with surfactant as the vehicle. Plasma and tissue samples were taken from the lambs for measurement of budesonide, 16α- hydroxy prednisolone, and budesonide palmitate using LC/MS/MS. Peak plasma budesonide concentrations were inversely correlated with the oxygenation index (correlation coefficient of -0.75). plasma budesonide concentrations were extremely low (~10% of expected) for two lambs that had high oxygenation indices and were excluded from further analyses. For the remaining 5 premature lambs, a non-compartmental analysis demonstrated an AUCinf of 148.77 ± 28.16 h*μg/L, half-life of 4.76 ± 1.79 h, and Cmax of 46.17 ± 17.71 µg/L. Using population pharmacokinetic methods, a onecompartment model with exponential residual error and first-order absorption adequately described the data. The apparent clearance and apparent volume of distribution of budesonide were estimated at 6.29 L/h (1.99 L/h/kg) and 29.1 L (9.2 L/kg), respectively. Budesonide and budesonide palmitate, but not 16α-hydroxy prednisolone, were detected in lung tissue. In this study, budesonide and its metabolites were not detected in the brain, which suggests that intratracheal instillation suggests that after local pulmonary deposition, there is no evidence of budesonide accumulation in the central nervous system. Overall, these results show that peak plasma budesonide concentrations are inversely correlated with the oxygenation index and that lung-specific delivery of budesonide avoids accumulation of budesonide in the brain.

The efficacy of fluticasone furoate administered in the morning or evening is comparable in patients with persistent asthma

BACKGROUND

The inhaled corticosteroid fluticasone furoate (FF) is efficacious as a once-daily treatment for the management of asthma. Asthma is associated with circadian changes, with worsening lung function at night. We compared the efficacy of once-daily FF in the morning or evening for the treatment of asthma.

METHODS

Adults with persistent bronchial asthma were enrolled into this randomised, repeat-dose, double-blind, double-dummy, placebo-controlled, three-way crossover study. After a 14-day run-in period, patients received either: FF 100 μg in the morning (AM); FF 100 μg in the evening (PM); or placebo, via the ELLIPTA(®) dry powder inhaler. Patients received all three treatments (14 ± 2 day duration) separated by a 14- to 21-day washout period. The primary endpoint was 24-h weighted mean forced expiratory volume in 1 s (FEV1) measured at the end of each 14-day treatment.

RESULTS

A total of 28 patients aged between 19 and 67 years were randomised and 21 (75%) completed all three study arms. Once-daily administration of FF 100 μg resulted in an increased 24-hour weighted mean FEV1; differences between the adjusted means for AM and PM FF dosing versus placebo were 0.077 L (90% confidence interval [CI]: 0.001, 0.152) and 0.105 L (90% CI: 0.029, 0.180), respectively (adjusted mean difference: -0.028 L [90% CI: -0.102, 0.045]). AM or PM doses had comparable incidences of adverse events (AEs; 18/23 versus 18/24, respectively), no serious AEs occurred.

CONCLUSION

AM and PM doses of once-daily FF 100 μg produced comparable improvements in lung function relative to placebo.

Evidence of hypothalamic-pituitary-adrenal axis suppression during moderate-to-high-dose inhaled corticosteroid use

The possible risk of adverse effects due to regular use of inhaled corticosteroids (ICS) is a real concern. Our aim was to describe the factors that have an impact on hypothalamic-pituitary-adrenal axis suppression (HPA-AS) in children and adolescents taking ICS regularly. The HPA axis status of patients who were on moderate-to-high-dose ICS [>176 and >264 μg/day fluticasone propionate-hydrofluoroalkane (FP-HFA) for patients 0-11 and ≥12 years, respectively] was investigated. Various types of ICS were converted to FP-HFA equivalent according to National Asthma Education and Prevention Program (NAEPP) guidelines. Participants with a baseline (8 a.m.) serum cortisol <15 μg/dL underwent a low-dose ACTH stimulation test (LDAT) to diagnose HPA-AS. Among 91 patients, 60 (75.9 %) participants underwent LDAT, and seven (7.7, 95 % CI 3.5-15.3 %) were diagnosed with HPA-AS. Ciclesonide was more frequently used by the participants with HPA-AS compared to patients with a normal HPA axis (42.9 vs. 4.8 %, p = 0.009). Use of ICS at moderate-to-high doses for at least 7 months distinguished participants with HPA-AS from those with a normal HPA axis. Among the duration, type, and dose of ICS, solely the use of ICS with a body mass index (BMI)-adjusted daily dose of ≥22 μg FP was found to increase the risk for HPA-AS (odds ratio (OR) 7.22, 95 % confidence interval (CI) 1.23-42.26, p = 0.028). The receiver operating characteristics (ROC) curve analysis revealed a cutoff value of 291 μg/day FP (area under the curve (AUC) = 0.840, p = 0.003) for predicting HPA-AS Conclusion: The prevalence of HPA-AS was found to be 7.7 % in children taking not only high-dose ICS but also moderate-dose ICS. Dose alone was found to be an actual risk factor for HPA-AS.

Pharmacometric Models for Characterizing the Pharmacokinetics of Orally Inhaled Drugs

During the last decades, the importance of modeling and simulation in clinical drug development, with the goal to qualitatively and quantitatively assess and understand mechanisms of pharmacokinetic processes, has strongly increased. However, this increase could not equally be observed for orally inhaled drugs. The objectives of this review are to understand the reasons for this gap and to demonstrate the opportunities that mathematical modeling of pharmacokinetics of orally inhaled drugs offers. To achieve these objectives, this review (i) discusses pulmonary physiological processes and their impact on the pharmacokinetics after drug inhalation, (ii) provides a comprehensive overview of published pharmacokinetic models, (iii) categorizes these models into physiologically based pharmacokinetic (PBPK) and (clinical data-derived) empirical models, (iv) explores both their (mechanistic) plausibility, and (v) addresses critical aspects of different pharmacometric approaches pertinent for drug inhalation. In summary, pulmonary deposition, dissolution, and absorption are highly complex processes and may represent the major challenge for modeling and simulation of PK after oral drug inhalation. Challenges in relating systemic pharmacokinetics with pulmonary efficacy may be another factor contributing to the limited number of existing pharmacokinetic models for orally inhaled drugs. Investigations comprising in vitro experiments, clinical studies, and more sophisticated mathematical approaches are considered to be necessary for elucidating these highly complex pulmonary processes. With this additional knowledge, the PBPK approach might gain additional attractiveness. Currently, (semi-)mechanistic modeling offers an alternative to generate and investigate hypotheses and to more mechanistically understand the pulmonary and systemic pharmacokinetics after oral drug inhalation including the impact of pulmonary diseases.

The efficacy of once-daily fluticasone furoate/vilanterol in asthma is comparable with morning or evening dosing

AIM

To investigate the effect of time of day of dosing (morning or evening) on lung function following administration of fluticasone furoate (FF)/vilanterol (VI) 100/25 mcg.

METHODS

Double-blind, placebo-controlled, randomised, three-way crossover study. Subjects with persistent asthma (N = 26) received FF/VI (morning or evening) or matching placebo once-daily for 14 (± 2 days) via dry powder inhaler (DPI). Weighted mean (0-24h) and pre-treatment FEV1 (morning and evening) were determined after the Day 14 evening dose, together with mean pre-treatment (morning and evening) peak expiratory flow (PEF) on Days 2-12.

RESULTS

FF/VI 100/25 administered morning or evening produced clinically significant increases in weighted mean FEV1: the differences [95% confidence interval (CI)] from placebo were 377 mL [293, 462] and 422 mL [337, 507], respectively; the difference between morning and evening dosing was -44 mL [-125, 36]. Day 14 pre-treatment morning FEV1 differences [95% CI] from placebo were 403 mL [272, 533] and 496 mL [369, 624] after morning and evening dosing, respectively; the morning:evening treatment difference was -94 mL [-221, 34]. Pre-treatment evening FEV1 differences [95% CI] from placebo were 275 mL [169, 380] and 309 mL [205, 413] after morning and evening dosing, respectively; the morning:evening treatment difference was -34 mL [-138, 70]. FF/VI (morning or evening) produced rapid increases in PEF with the full effect apparent after the first dose and maintained throughout the 14-day treatment period.

CONCLUSION

FF/VI 100/25 produces comparable improvements in lung function whether dosed in the morning or evening in subjects with persistent asthma.

Impact of study design on the evaluation of inhaled and intranasal corticosteroids' effect on hypothalamic-pituitary-adrenal axis function, part I: general overview of HPA axis study design

Inhaled and intranasal corticosteroids (ICS and INS) are among the mainstays of the treatment for asthma and allergic rhinitis, respectively, and also carry the potential to suppress the hypothalamic-pituitary-adrenal (HPA) axis. Several important factors affect the interpretability of trials investigating the impact of ICS and INS on the HPA axis. This paper reviews 106 published clinical trials, peer-reviewed articles, and New Drug Application reviews of approved ICS and INS, using MEDLINE and Drugs@FDA database. The trials included in this review evaluated the potential impact on HPA axis function of eight approved single-ingredient ICS and INS (beclomethasone dipropionate, budesonide, ciclesonide, flunisolide, fluticasone furoate, flucticasone propionate, mometasone furoate, and triamcinolone acetonide) and combination products containing these ingredients. The most commonly utilized design was blinded, placebo controlled, and short term (<6 weeks) for adult trials and blinded, placebo controlled, and long term (≥6 weeks) for pediatric trials. Factors potentially affecting trial results include the choice of dose, dosing duration, assay sensitivity, statistical methodology, and the study population evaluated (patients or healthy volunteers). All of these factors have the potential to affect the level of adrenal suppression detected. In conclusion, to be informative, a HPA axis study should be well designed and carefully implemented to minimize variability in results and improve the overall interpretability of data obtained.

Inhaled fluticasone and the hormonal and inflammatory response to brief exercise

PURPOSE

Inhaled corticosteroids (ICS) improve symptoms in lung diseases, such as asthma. Initial data suggest that the effects of ICS remain localized in the lung; however, recent studies demonstrate alteration to the peripheral immune system in patients with asthma. We sought to evaluate the effect of ICS on peripheral immune mediators and hypothalamic-pituitary-adrenal axis and their response to exercise in healthy men.

METHODS

Eleven healthy males (18-30 yr old) were placed on 2 wk of fluticasone proprionate (440 μg) twice daily. A 30-min bout of exercise was performed on a cycle ergometer at approximately 70% of peak work rate before and after the start of ICS. Blood was sampled before and after exercise. Cytokines and hypothalamic-pituitary-adrenal axis mediators were measured by ELISA, and fluticasone was measured by liquid chromatography/tandem mass spectrometry.

RESULTS

After ICS treatment, cortisol and adrenocorticotropin were decreased, and a blunted exercise response was observed for cortisol, adrenocorticotropin, and growth hormone. Peripheral leukocytes and neutrophils were significantly increased in response to exercise in both the untreated and the ICS-treated conditions and at baseline after ICS treatment. Interleukin-6 was elevated with ICS treatment, but the exercise response was blunted. Circulating median fluticasone levels were 0.15 ng·mL(-1) and were increased to 0.20 ng·mL(-1) in response to exercise.

CONCLUSIONS

Exercise revealed deficits in growth hormone production after ICS treatment not identified by static markers. Neutrophils were shown to be surrogate markers of the systemic effect of ICS. Exercise significantly increased circulating levels of fluticasone. Exercise challenge tests can be used to assess the physiological effect of exogenous corticosteroids.