Following inhalation of the glycopyrronium and formoterol combination, the pharmacokinetics of each component was similar to those observed when each active substance was administered separately. For pharmacokinetic purposes each component can therefore be considered separately.
Effect of a spacer
The use of Bevespi Aerosphere with the Aerochamber Plus Flow-Vu spacer in COPD patients increased the total systemic exposure to glycopyrronium (as measured by AUC0-12) by 16% while formoterol exposure was unchanged.
Absorption
Following inhaled administration of Bevespi Aerosphere in subjects with COPD, glycopyrronium Cmax occurred at approximately 5 minutes, and formoterol Cmax occurred within 20 to 60 minutes. Steady state is achieved within 2-3 days of repeated dosing of Bevespi Aerosphere, and the extent of exposure is approximately 2.3 times and 1.5 times higher than after the first dose, for glycopyrronium and formoterol, respectively.
A lung deposition study with Bevespi Aerosphere conducted in healthy volunteers demonstrated that on average 38% of the nominal dose is deposited into the lung. Both central and peripheral deposition were observed.
Distribution
Glycopyrronium
The estimated glycopyrronium Vc/F (volume of the central compartment), and Vp1/F (volume of the peripheral compartment) are 741 L, and 2990 L, respectively, via population pharmacokinetic analysis. Over the concentration range of 2-500 nmol/L, plasma protein binding of glycopyrronium ranged from 43% to 54%.
Formoterol
The estimated formoterol Vc/F (volume of the central compartment), and Vp1/F (volume of the peripheral compartment) are 1030 L, and 647 L, respectively, via population pharmacokinetic analysis. Over the concentration range of 10-500 nmol/L, plasma protein binding of formoterol ranged from 46% to 58%.
Biotransformation
Glycopyrronium
Based on literature, and an in-vitro human hepatocyte study, metabolism plays a minor role in the overall elimination of glycopyrronium. CYP2D6 was found to be the predominant enzyme involved in the metabolism of glycopyrronium.
In-vitro studies indicate the glycopyrronium does not inhibit any subtype of cytochrome P450 and that there is no induction of CYP1A2, 2B6, or 3A4.
Formoterol
The primary metabolism of formoterol is by direct glucuronidation and by O-demethylation followed by conjugation to inactive metabolites. Secondary metabolic pathways include deformylation and sulfate conjugation. CYP2D6 and CYP2C have been identified as being primarily responsible for O-demethylation.
In-vitro studies indicate that formoterol does not inhibit the CYP450 enzymes at therapeutically relevant concentrations.
Elimination
After IV administration of a 0.2 mg dose of radiolabelled glycopyrronium, 85% of the dose was recovered in urine 48 hours post dose and some of radioactivity was also recovered in bile. The terminal elimination half-life of glycopyrronium following oral inhalation derived via population pharmacokinetics analysis was 15 hours.
The excretion of formoterol was studied in six healthy subjects following simultaneous administration of radiolabelled formoterol via the oral and IV routes. In that study, 62% of the radiolabelled formoterol was excreted in the urine while 24% was eliminated in the faeces. The terminal elimination half-life of formoterol following oral inhalation derived via population pharmacokinetics analysis was 13 hours.
Linearity/non-linearity
Linear pharmacokinetics were observed for glycopyrronium (dose range: 14.4 to 115.2 mcg) and formoterol (dose range: 2.4 to 19.2 mcg) after oral inhalation.
Special patient populations
Elderly patients
Based on available data, no adjustment of the dosage of Bevespi Aerosphere in geriatric patients is necessary.
Renal impairment
Studies evaluating the effect of renal impairment on the pharmacokinetics of glycopyrronium and formoterol have not been conducted. The effect of renal impairment on the exposure to glycopyrronium and formoterol for up to 12 weeks was evaluated in a population pharmacokinetic analysis. Estimated glomerular filtration rate (eGFR) varied from 30-196 mL/min, representing a range of moderate to no renal impairment. The systemic exposure (AUC0-12) in subjects with COPD with moderate-severe renal impairment (eGFR of 30-45 mL/min) is approximately 30% higher for glycopyrronium compared to subjects with COPD with normal renal function (eGFR of >90 mL/min). Subjects with COPD with both low body weight and moderate-severe impaired renal function may have an approximate doubling of systemic exposure to glycopyrronium. Renal function was found not to affect exposure to formoterol.
Hepatic impairment
No pharmacokinetic studies have been performed with Bevespi Aerosphere in patients with hepatic impairment. However, because formoterol is primarily eliminated via hepatic metabolism, an increased exposure can be expected in patients with severe liver impairment. Glycopyrronium is primarily cleared from the systemic circulation by renal excretion and hepatic impairment would therefore not be expected to lead to unsafe systemic exposure.
Other special populations
A population pharmacokinetic analysis of glycopyrronium was performed based on data collected in a total of 311 subjects with COPD. The pharmacokinetics of glycopyrronium was best described by a two-compartment disposition model with first-order absorption and linear elimination. The typical clearance (CL/F) of glycopyrronium was 124 L/h.
A population pharmacokinetic analysis of formoterol was performed based on data collected in a total of 437 subjects with COPD. The pharmacokinetics of formoterol was best described by a two-compartment disposition model with a first-order rate constant of absorption and linear elimination. The typical clearance (CL/F) of formoterol was 99 L/h.
Dose adjustments are not necessary based on the effect of age, sex and weight on the pharmacokinetic parameters of glycopyrronium and formoterol.
There were no major differences in total systemic exposure (AUC) for both compounds between healthy Japanese and Western subjects. Insufficient pharmacokinetic data are available to compare exposure for other ethnicities or races.