Performance of Multiple-Batch Approaches to Pharmacokinetic Bioequivalence Testing for Orally Inhaled Drug Products with Batch-to-Batch Variability.

Batch-to-batch pharmacokinetic (PK) variability of orally inhaled drug products has been documented and can render single-batch PK bioequivalence (BE) studies unreliable; results from one batch may not be consistent with a repeated study using a different batch, yet the goal of PK BE is to deliver a product comparison that is interpretable beyond the specific batches used in the study. We characterized four multiple-batch PK BE approaches to improve outcome reliability without increasing the number of clinical study participants. Three approaches include multiple batches directly in the PK BE study with batch identity either excluded from the statistical model ("Superbatch") or included as a fixed or random effect ("Fixed Batch Effect," "Random Batch Effect").

Batch Selection via In Vitro/In Vivo Correlation in Pharmacokinetic Bioequivalence Testing.

Pharmacokinetic differences between manufacturing batches, well established for inhaled drug products, preclude control of patient risk in the customary two-way (single batch) pharmacokinetic bioequivalence crossover design if batches are randomly chosen. European regulators have recommended selecting a "typical" in vitro batch to represent each product in pharmacokinetic bioequivalence testing. We explored the feasibility of this approach to control patient risk (the "false equivalence", or Type I, error rate).

Performance of the Population Bioequivalence (PBE) Statistical Test with Impactor Sized Mass Data.

This article extends previous work studying performance characteristics of the population bioequivalence (PBE) statistical test recommended by the US Food and Drug Administration (FDA) for orally inhaled and nasal drug products. Based on analysis of a metered dose inhaler database for impactor sized mass, a simulation study was designed to compare performance of the recommended PBE approach with several modified or alternative approaches. These included an extended PBE that separately modeled within-batch (can) and between-batch (batch) variability and average bioequivalence (ABE) tests that modeled with or without between-batch variability and with or without log-transformation.

Performance of the Population Bioequivalence (PBE) Statistical Test Using an IPAC-RS Database of Delivered Dose from Metered Dose Inhalers.

This article reports performance characteristics of the population bioequivalence (PBE) statistical test recommended by the US Food and Drug Administration (FDA) for orally inhaled products. A PBE Working Group of the International Pharmaceutical Aerosol Consortium on Regulation and Science (IPAC-RS) assembled and considered a database comprising delivered dose measurements from 856 individual batches across 20 metered dose inhaler products submitted by industry. A review of the industry dataset identified variability between batches and a systematic lifestage effect that was not included in the FDA-prescribed model for PBE.

Clinical Bioequivalence of OT329 SOLIS and ADVAIR DISKUS in Adults with Asthma.

Rationale: OT329 SOLIS is a generic candidate for the branded asthma treatment, ADVAIR DISKUS (fluticasone propionate/salmeterol xinafoate), and, as such, the manufacturer is required to provide evidence of clinical "bioequivalence" as a condition for regulatory approval.

Objectives: The objective of the current study was to determine if SOLIS and DISKUS provided bioequivalent improvements in lung function at two time points: Day 1 and Week 4.

Methods: This study was a randomized, multiple-dose, placebo-controlled, parallel-group design conducted in the United States (NCT02260492) with a 2-week run-in followed by a 4-week treatment period.

Evaluation of a Scenario in Which Estimates of Bioequivalence Are Biased and a Proposed Solution: tlast (Common).

In bioequivalence (BE) testing, it is the convention to identify tlast separately for each concentration-vs-time profile. Within-subject differences in tlast between treatments can arise when assay sensitivity is reached during washout, causing profiles to fall below the limit of quantitation (LOQ) at different sampling times. The resulting tlast difference may be systematic, due to true differences in exposure, and/or random, due to measurement noise.

Human pharmacokinetics/pharmacodynamics of an interleukin-4 and interleukin-13 dual antagonist in asthma.

Pitrakinra, a 15-kDa recombinant human interleukin-4 mutein, targets allergic Th2 inflammation by competitively binding to interleukin-4 receptor alpha to interfere with interleukin-4 and interleukin-13 action. The authors characterized pitrakinra pharmacokinetics using data from 96 atopic patients, then compared pharmacokinetics with pharmacological response in asthma following subcutaneous versus inhalation dosing. A 1-compartment systemic model with site-specific absorption describes pitrakinra pharmacokinetics following subcutaneous, nebulization, and inhalation powder delivery.

Effect of an interleukin-4 variant on late phase asthmatic response to allergen challenge in asthmatic patients: results of two phase 2a studies.

Background: Increases in T helper (Th) 2 cytokine concentrations have been seen in atopic asthma, with interleukin 4 and interleukin 13 thought to have a role in the physiological response to allergen challenge. Our aim was to assess the therapeutic effect of pitrakinra, an interleukin-4 variant that targets allergic Th2 inflammation by potently inhibiting the binding of interleukin 4 and interleukin 13 to interleukin-4Ralpha receptor complexes.

Methods: In two independent randomised, double-blind, placebo-controlled, parallel group phase 2a clinical trials, patients with atopic asthma were treated with pitrakinra or placebo via two routes.

Force enhancement by PEG during ramp stretches of skeletal muscle.

We have investigated the effects of a stronger actomyosin bond on force (Ps) during rapid stretch of active permeabilized rabbit psoas muscle fibers as a function of temperature from 5 to 30 degrees C. The strength of the actomyosin bond is enhanced by addition of polyethylene glycol (PEG), especially in pre-powerstroke states [Chinn et al. (2000) Biophys J 49: 437-451].