Pharmacokinetic Models for Inhaled Fluticasone Propionate and Salmeterol Xinafoate to Quantify Batch-to-Batch Variability.

Advair Diskus is an essential treatment for asthma and chronic obstructive pulmonary disease. It is a dry powder inhaler with a combination of fluticasone propionate (FP) and salmeterol xinafoate (SX). However, the pharmacokinetics (PK) batch-to-batch variability of the reference-listed drug (RLD) hindered its generic product development. This work developed the PK models for inhaled FP and SX that could represent potential batch variability. Two batches each of the reference and the test product (R1, R2, T1, T2) of Advair Diskus (100 µg FP/50 µg SX inhalation) were administered to 60 healthy subjects in a 4-period, 4-sequence crossover study. The failure of the bioequivalence (BE) between R1 and R2 confirmed the high between-batch variability of the RLD. Non-linear mixed effect modeling was used to estimate the population mean PK parameters for each batch. For FP, a 2-compartment model with a sequential dual zero-order absorption best described the PK profile. For SX, a 2-compartment model with a first-order absorption model best fit the data. Both models were able to capture the plasma concentration, the maximum concentration, and the total exposure (AUCinf) adequately for each batch, which could be used to simulate the BE study in the future. In vitro properties were also measured for each batch, and the batch with a higher fraction of the fine particle (diameter < 1 µm, < 2 µm) had a higher AUCinf. This positive correlation for both FP and SX could potentially assist the batch selection for the PK BE study.

The Role of ICS/LABA Fixed-Dose Combinations in the Treatment of Asthma and COPD: Bioequivalence of a Generic Fluticasone Propionate-Salmeterol Device.

Both asthma and chronic obstructive pulmonary disease (COPD) are inflammatory chronic respiratory conditions with high rates of morbidity and mortality worldwide. The objectives of this review are to briefly describe the pathophysiology and epidemiology of asthma and COPD, discuss guideline recommendations for uncontrolled disease, and review a new generic option for the treatment of asthma and COPD. Although mild forms of these diseases may be controlled with as-needed pharmacotherapy, uncontrolled or persistent asthma and moderate or severe COPD uncontrolled by bronchodilators with elevated eosinophilia or frequent exacerbations may require intervention with combination therapy with inhaled corticosteroids (ICS) and long-acting beta agonists (LABAs), according to international guidelines. Fixed-dose combinations of ICS/LABA are commonly prescribed for both conditions, with fluticasone propionate (FP) and salmeterol forming a cornerstone of many treatment plans. An oral inhalation powder containing the combination of FP and salmeterol has been available as Advair Diskus® in the United States for almost 20 years, and the first and only substitutable generic version of this product has recently been approved for use: Wixela™ Inhub™. Bioequivalence of Wixela Inhub and Advair Diskus has been established. Furthermore, the Inhub inhaler was shown to be robust and easy to use, suggesting that Wixela Inhub may provide an alternative option to Advair Diskus for patients with asthma or COPD requiring intervention with an ICS/LABA.

Equivalent Systemic Exposure to Fluticasone Propionate/Salmeterol Following Single Inhaled Doses from Advair Diskus and Wixela Inhub: Results of Three Pharmacokinetic Bioequivalence Studies.

Background: Wixela® Inhub® was developed to deliver inhaled fluticasone propionate/salmeterol (FP/S) combination as a substitutable generic equivalent to Advair® Diskus®. These studies aimed to confirm the pharmacokinetic bioequivalence (BE) of FP/S after single doses of Wixela Inhub (test [T]) and Advair Diskus (reference [R]). Methods: Three open-label, randomized, two-way crossover, single-dose studies in healthy subjects (N = 66 each) compared the systemic exposure of FP and salmeterol after inhalation from three dose strengths of FP/S (100/50, 250/50, or 500/50 µg) delivered from T and R. Primary BE endpoints were the area under the plasma concentration-time curve from time = 0 to the last measurable concentration (AUC(0-t)) and the maximum observed plasma concentration (Cmax) for both FP and S. The BE acceptance criteria specified that the 90% confidence intervals (CIs) of the geometric mean T/R ratios for AUC(0-t) and Cmax can be contained within 0.80-1.25 for both FP and salmeterol. Results: Wixela Inhub met the acceptance criteria for BE for FP and salmeterol at each dose strength. Estimated AUC(0-t) and Cmax geometric mean ratios (T/R [90% CI]) for FP were, respectively, 1.04 (1.00-1.08) and 0.92 (0.87-0.96) for 100/50 µg FP/S, 1.07 (1.02-1.13) and 1.01 (0.95-1.07) for 250/50 µg, and 0.97 (0.92, 1.00) and 0.90 (0.86-0.93) for 500/50 µg. Estimated AUC(0-t) and Cmax ratios for salmeterol were, respectively, 1.08 (1.04-1.11) and 1.00 (0.94-1.04) for 100/50 µg FP/S, 1.03 (0.99-1.07) and 0.93 (0.87-1.00) for 250/50 µg, and 1.00 (0.96-1.04) and 0.86 (0.81-0.91) for 500/50 µg. FP/S at all doses via both T and R was comparably well tolerated. Conclusions: Wixela Inhub was bioequivalent to Advair Diskus at all three dose strengths for both FP and S, providing direct evidence of equivalent systemic safety and indirect evidence for equivalent pulmonary deposition.

Clinical Bioequivalence of Wixela Inhub and Advair Diskus in Adults With Asthma.

Background: Wixela® Inhub® is a dry powder inhaler approved as a generic equivalent to Advair® Diskus® (fluticasone propionate [FP]/salmeterol fixed-dose combination) for patients with asthma or chronic obstructive pulmonary disease (COPD). This study aimed at confirming the local (lung) therapeutic equivalence of both the FP and salmeterol components of Wixela Inhub (test [T]) to Advair Diskus (reference [R]) after inhalation. Methods: This randomized, double-blind, double-dummy, placebo-controlled, parallel-group study in patients ≥18 years with mild-to-moderate persistent asthma compared the local therapeutic equivalence (using forced expiratory volume in 1 second [FEV1]) of FP/salmeterol (100/50 µg) after inhaled delivery via T and R. Results: Randomized patients (N = 1127) received T (n = 512), R (n = 512), or placebo (n = 103). T and R significantly increased day 1 FEV1 area under the effect curve over 12 hours of the change from baseline (AUC[0-12]) and day 29 trough FEV1 over placebo, indicating that these endpoints were sufficiently sensitive for evaluation of bioequivalence. On day 1, T and R each increased FEV1 AUC(0-12) over placebo (3.134 L•h [T], 2.677 L•h [R]; each p < 0.0001). Following twice-daily dosing for 28 days, T and R also each increased trough FEV1 (measured on day 29) over placebo (235 mL [T], 215 mL [R]; each p < 0.0001). Least-squares mean T/R ratios (90% confidence intervals) for day 1 FEV1 AUC(0-12) and day 29 trough FEV1 were 1.120 (1.016-1.237) and 1.069 (0.938-1.220), respectively, indicating that T and R were bioequivalent for both co-primary endpoints. FP/salmeterol was well tolerated when administered via either T or R. Conclusions: These results demonstrate that the therapeutic effects of Wixela Inhub are bioequivalent to Advair Diskus in the lung. Wixela Inhub represents a therapeutically equivalent new FP/salmeterol treatment option for use in the treatment of asthma and COPD.

The pharmacokinetics, safety, and tolerability of single, high-strength doses of fluticasone propionate and fluticasone propionate/salmeterol delivered via a novel multidose dry powder inhaler in adolescents and adults with persistent asthma.

OBJECTIVE: Characterize fluticasone propionate (Fp) and combination fluticasone propionate and salmeterol (FS) pharmacokinetic and safety profiles, delivered via a novel, inhalation-driven, multidose dry powder inhaler (MDPI). METHODS: This multicenter, open-label, four-period crossover, single-dose study randomized patients aged ≥12 years with persistent asthma to Fp MDPI 200 mcg, FS MDPI 200/12.5 mcg, Fp dry powder inhaler (DPI) 500 mcg (250 mcg × 2 inhalations), or FS DPI 500/50 mcg. Blood samples for determination of Fp and salmeterol pharmacokinetic parameters including Cmax, AUC0-t, AUC0-inf, tmax, and t½ were collected predose through 36 h postdose (14 time points). Safety assessments comprised adverse events, vital signs, and physical examinations. The institutional review board approved the study protocol. RESULTS: The pharmacokinetic analysis set and safety population each included 40 patients. Fp systemic exposure (Cmax, AUC0-t, and AUC0-inf) was highest for Fp DPI 500 mcg and similar for Fp MDPI 200 mcg, FS MDPI 200/12.5 mcg, and FS DPI 500/50 mcg. Fp geometric mean t½ values were similar across treatments. Salmeterol Cmax was 20% lower and AUC0-t and AUC0-inf were approximately 50% lower with FS MDPI versus FS DPI. Median tmax and geometric mean t½ were similar between FS MDPI and FS DPI. Adverse events were similar across treatments with no relevant changes in vital signs, physical examinations, or hematology test results. CONCLUSIONS: Fp MDPI and FS MDPI produced similar or lower systemic exposure to Fp and salmeterol, despite lower doses, versus conventional DPI devices, suggesting improved efficiency due to formulation and device differences.

Between-Batch Pharmacokinetic Variability Inflates Type I Error Rate in Conventional Bioequivalence Trials: A Randomized Advair Diskus Clinical Trial.

We previously demonstrated pharmacokinetic differences among manufacturing batches of a US Food and Drug Administration (FDA)-approved dry powder inhalation product (Advair Diskus 100/50) large enough to establish between-batch bio-inequivalence. Here, we provide independent confirmation of pharmacokinetic bio-inequivalence among Advair Diskus 100/50 batches, and quantify residual and between-batch variance component magnitudes. These variance estimates are used to consider the type I error rate of the FDA's current two-way crossover design recommendation. When between-batch pharmacokinetic variability is substantial, the conventional two-way crossover design cannot accomplish the objectives of FDA's statistical bioequivalence test (i.e., cannot accurately estimate the test/reference ratio and associated confidence interval). The two-way crossover, which ignores between-batch pharmacokinetic variability, yields an artificially narrow confidence interval on the product comparison. The unavoidable consequence is type I error rate inflation, to ∼25%, when between-batch pharmacokinetic variability is nonzero. This risk of a false bioequivalence conclusion is substantially higher than asserted by regulators as acceptable consumer risk (5%).

Dose-ranging study of salmeterol using a novel fluticasone propionate/salmeterol multidose dry powder inhaler in patients with persistent asthma.

BACKGROUND: New inhalation devices with improved lung delivery may allow the use of lower salmeterol doses for treatment of asthma. OBJECTIVE: To determine the dose of salmeterol administered from a novel fluticasone propionate/salmeterol (FS) inhalation-driven, multidose dry powder inhaler (MDPI), which provides comparable efficacy and safety to FS dry powder inhaler (DPI). METHODS: This double-blind, six-period crossover, dose-ranging study randomized 72 patients (ages ≥12 years; with persistent asthma and predose maximum forced expiratory volume in 1 second [FEV1] of 40-85% of the predicted normal) to treatment sequences (one dose per treatment), which consisted of FS MDPI 100/6.25, 100/12.5, 100/25, 100/50 µg; fluticasone propionate (Fp) MDPI 100 µg; and open-label FS DPI 100/50 µg. The primary efficacy variable was the baseline-adjusted FEV1 area under the curve over 12 hours after the dose (AUC0-12). Pharmacokinetics and tolerability were also assessed. RESULTS: FEV1 AUC0-12 was significantly higher with all FS MDPI doses and FS DPI versus Fp MDPI (p < 0.0001), and with FS MDPI 100/50 µg versus FS DPI (least squares [LS] mean, 57.88 mL; p = 0.0017). FEV1 AUC0-12 trended toward higher efficacy with FS MDPI 100/25 µg (LS mean, 34.14 mL; p = 0.0624) and was comparable with FS MDPI 100/12.5 µg (LS mean, 3.42 mL; p = 0.8503) versus FS DPI. Salmeterol area under the plasma concentration-versus-time curve from time 0 to the time of the last measurable concentration (AUC0-t) for FS MDPI 100/12.5 µg and 100/25 µg was lower versus FS DPI 100/50 µg; AUC0-t for FS MDPI 100/50 µg was higher than FS DPI 100/50 µg. All FS MDPI doses were generally well tolerated. CONCLUSION: All FS MDPI doses produced greater efficacy versus Fp MDPI. FS MDPI 100/12.5 µg demonstrated similar efficacy to FS DPI 100/50 µg with less salmeterol exposure. Clinicaltrials.gov NCT02139644, NCT02175771, and NCT02141854.

Assessment of lung deposition and analysis of the effect of fluticasone/salmeterol hydrofluoroalkane (HFA) pressurized metered dose inhaler (pMDI) in stable persistent asthma patients using functional respiratory imaging.

BACKGROUND: Unambiguously for inhaled products, PK measures are best suited for ensuring that the total systemic exposure is equivalent for two products but cannot provide regional information about lung deposition and structural changes. Functional respiratory imaging (FRI) has been demonstrated to be sensitive for distinguishing small but imperative differences related to a single treatment. METHODS: In this study FRI is used in 16 asthmatic patients to assess equivalence in regional deposition for two products (fluticasone/salmeterol, test and reference) by directly measuring regional functional and structural changes within the lungs following its administration. RESULTS: No differences were observed between the lung deposition patterns and the effects on lung structure and function of two products, having the same formulation and manufactured by different organizations using FRI. CONCLUSIONS: Results using FRI complement PK assessments. The added value of this approach to the conventional clinical methods could be significant.

Batch-to-batch pharmacokinetic variability confounds current bioequivalence regulations: A dry powder inhaler randomized clinical trial.

Current pharmacokinetic (PK) bioequivalence guidelines do not account for batch-to-batch variability in study design or analysis. Here we evaluate the magnitude of batch-to-batch PK variability for Advair Diskus 100/50. Single doses of fluticasone propionate and salmeterol combinations were administered by oral inhalation to healthy subjects in a randomized clinical crossover study comparing three different batches purchased from the market, with one batch replicated across two treatment periods. All pairwise comparisons between different batches failed the PK bioequivalence statistical test, demonstrating substantial PK differences between batches that were large enough to demonstrate bio-inequivalence in some cases. In contrast, between-replicate PK bioequivalence was demonstrated for the replicated batch. Between-batch variance was ∼40-70% of the estimated residual error. This large additional source of variability necessitates re-evaluation of bioequivalence assessment criteria to yield a result that is both generalizable and consistent with the principles of type I and type II error rate control.

Systemic Exposures of Fluticasone Propionate and Salmeterol Following Inhalation via Metered Dose Inhaler with the Mini Spacer Compared with the Aerochamber Plus Spacer.

BACKGROUND: The Mini Spacer has been developed for use with Ventolin(®) metered dose inhalers (MDIs) to improve accessibility to affordable spacers in developing countries. To ensure patient safety is not compromised if the Mini Spacer is used off-label with fluticasone propionate (FP) or salmeterol/FP combination (SFC) MDIs (currently not recommended), this study compared the systemic exposure of FP and salmeterol following delivery of FP and SFC MDIs with the Mini Spacer and the Aerochamber Plus(®) spacer (Aerochamber). METHODS: This was an open-label, randomized, single dose, crossover study in healthy subjects that evaluated four treatments: i) FP 250 µg MDI with Mini Spacer; ii) FP 250 µg MDI with Aerochamber; iii) SFC 25/250 µg with Mini Spacer; iv) SFC 25/250 µg with Aerochamber. There was a minimum 7 day washout between treatments. Pharmacokinetic samples were collected over 24 hours post-dose. The co-primary endpoints were FP area under the concentration-time curve from time zero to 24 h [FP AUC(0-24)] and salmeterol maximum plasma concentration [Cmax]. RESULTS: FP systemic exposure in terms of AUC(0-24) was lower following inhalation with the Mini Spacer compared with the Aerochamber for both FP 250 µg (Mini Spacer/Aerochamber Ratio 0.76 [90% CI: 0.57-1.01]) and SFC 25/250 µg (Ratio 0.74 [90% CI: 0.56-0.99]). Salmeterol systemic exposure was also lower following SFC 25/250 µg with Mini Spacer compared with Aerochamber (Cmax Ratio 0.90 [90% CI 0.48-1.66]). The incidence of adverse events was low and similar with each treatment. CONCLUSIONS: In the event of use of the Mini Spacer with FP and SFC MDIs, which is not recommended, FP and salmeterol systemic exposure is unlikely to be higher than if MDIs were to be used with the Aerochamber. However, these data do not indicate that the Mini Spacer and Aerochamber are interchangeable.

Population pharmacokinetics of fluticasone propionate/salmeterol using two different dry powder inhalers.

The combination of fluticasone propionate (FLP) and salmeterol (SAL) is often used in clinical practice for the treatment of pulmonary disorders. The purpose of this study was to explore the pharmacokinetics (PK) of inhaled FLP and SAL, after concomitant administration, in healthy male and female subjects using two dry powder inhalers. Plasma concentration (C)-time (t) data were obtained from a single dose, two-sequence, two-period, crossover (2×2) bioequivalence (BE) study. Activated charcoal was co-administered in order to prohibit absorption from the gastrointestinal tract. A number of 60 subjects were recruited, while 57 of them completed the study and were included in the PK analysis. Initially, PK parameters of FLP and SAL were estimated using the classic non-compartmental methods. Subsequently, BE assessment was applied to the estimated PK parameters of the two dry powder inhalers. Special focus was placed on the population PK analysis of the C-t data, which were pooled together. 'Treatment' (i.e., test or reference) and 'period' of the BE study were considered as covariates. A variety of structural and residual error models were tested to find the one which best described the plasma C-t data of FLP and SAL. Demographic data were also evaluated for their impact on the PK parameters. Several goodness-of-fit criteria were utilized. The non-compartmental PK estimates of this study were in agreement with previously reported values. The population PK analysis showed that FLP data were described by a two-compartment model with first-order absorption and elimination kinetics. Body weight was found to affect significantly absorption rate constant, inter-compartmental clearance, and volume of distribution of the peripheral compartment. As body weight increases, the values of these PK parameters also rise. For SAL, the best results were obtained when a two-compartment disposition model was used assuming very rapid absorption kinetics (like intravenous bolus) and first-order elimination kinetics. Gender was found to be a significant covariate on clearance, with men exhibiting higher clearance than women.

Comparison of the Pharmacokinetics of Salmeterol and Fluticasone Propionate 50/100 µg Delivered in Combination as a Dry Powder Via a Capsule-Based Inhaler and a Multi-Dose Inhaler.

BACKGROUND AND OBJECTIVES: The Rotacaps(®)/Rotahaler(®) system is a single unit dose inhaler being developed to deliver inhaled salmeterol/fluticasone propionate combination (SFC) as an alternative treatment option to the metered dose inhaler and the multi-dose dry powder inhaler, Diskus(®). The aim of this study was to compare the systemic exposure of SFC 50/100 µg following delivery via the Rotacaps(®)/Rotahaler(®) and the Diskus(®). METHODS: This was an open-label, randomized, cross-over, repeat-dose (3.5 days of twice-daily dosing) study comparing salmeterol and fluticasone propionate systemic exposure following inhaled SFC 50/100 µg delivered via the Rotacaps(®)/Rotahaler(®) and Diskus(®), in healthy subjects. Pharmacokinetic sampling was conducted over 12 h post-dose on the last day of each treatment. Pharmacokinetic samples were analysed using solid phase extraction followed by high performance liquid chromatography/tandem mass spectrometry. Co-primary endpoints were fluticasone propionate area under the concentration-time curve over the dosing interval (AUC0-τ ) and salmeterol maximum plasma concentration (C max) on the last day of treatment. RESULTS: Following SFC 50/100 µg Rotacaps(®)/Rotahaler(®), fluticasone propionate and salmeterol systemic exposures were comparable with Diskus(®) in terms of both AUC0-τ [geometric mean ratio (GMR) with 90 % confidence interval (CI) of Rotahaler(®)/Diskus(®) for fluticasone propionate: 0.98 (0.91, 1.06) and salmeterol: 1.04 (0.99, 1.10)] and C max [GMR (90 % CI) for fluticasone propionate: 1.04 (0.94, 1.15) and salmeterol: 0.97 (0.87, 1.08)], meeting the pre-defined criteria for comparability (upper limit of the 90 % CI for the GMRs (Rotahaler(®)/Diskus(®)) ≤1.25]. SFC delivered from both inhalers was well tolerated. CONCLUSIONS: SFC 50/100 µg Rotacaps(®)/Rotahaler(®) showed comparable fluticasone propionate and salmeterol systemic exposure to Diskus(®) for all pharmacokinetic endpoints with GMR and both upper and lower limits of 90 % CIs within conventional acceptance criteria for bioequivalence (0.8, 1.25), sufficient for considering progression of the Rotacaps(®)/Rotahaler(®) product for further clinical development.

Pharmacokinetics of fluticasone propionate and salmeterol delivered as a combination dry powder via a capsule-based inhaler and a multi-dose inhaler.

AIM: To compare salmeterol (SALM) and fluticasone propionate (FP) systemic exposure following inhaled salmeterol/fluticasone propionate combination (SFC) from a unit-dose capsule-based inhaler (Rotacaps(®)/Rotahaler(®)) and a multi-dose dry powder inhaler (Diskus(®)) in healthy volunteers. METHODS: An open-label, randomised, repeat-dose, cross-over, adaptive design study (n = 36 in each part) evaluated SFC 50/250 µg and SFC 50/100 µg in Rotacaps used with two types of Rotahaler inhalers (airflow resistance similar to (S) and lower than (L) Diskus) versus the Diskus. Primary endpoints were area under the concentration-time curve over the dosing interval [AUC0-τ] and maximum plasma concentration [Cmax]. RESULTS: SFC 50/250 µg Rotacaps/Rotahaler (S) showed 1.2-1.9-fold greater FP and SALM systemic exposure compared with Diskus. FP and SALM systemic exposure were comparable to DISKUS following SFC 50/250 µg Rotacaps/Rotahaler (L) (90% CI of ratio of Rotahaler to DISKUS within 0.8-1.25) for salmeterol (AUC0-τ and Cmax) and FP (AUC0-τ). Following SFC 50/100 µg Rotacaps/Rotahaler (L), FP and SALM systemic exposures were 1.2-1.4 fold higher in terms of FP (AUC0-τ and Cmax) and salmeterol (Cmax) compared with Diskus. SFC at both doses and via both inhalers was well tolerated. CONCLUSIONS: SFC 50/250 µg Rotacaps/Rotahaler (L) showed comparable systemic exposure to Diskus in terms of FP AUC and SALM AUC and Cmax. These results merit further progression of SFC 50/250 µg Rotacaps/Rotahaler (L) to phase 3 clinical evaluation in asthma and COPD patients. The lack of pharmacokinetic comparability between the inhalers for SFC 50/100 µg requires further evaluation.