Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

5.1   Pharmacodynamic properties
Pharmacotherapeutic group: Drugs for obstructive airway diseases, anticholinergics, ATC code: R03BB06

Mechanism of action
Glycopyrronium is an inhaled long-acting muscarinic receptor antagonist (anticholinergic) for once-daily maintenance bronchodilator treatment of COPD. Parasympathetic nerves are the major bronchoconstrictive neural pathway in airways, and cholinergic tone is the key reversible component of airflow obstruction in COPD. Glycopyrronium works by blocking the bronchoconstrictor action of acetylcholine on airway smooth muscle cells, thereby dilating the airways.

Glycopyrronium bromide is a high affinity muscarinic receptor antagonist. A greater than 4-fold selectivity for the human M3 receptors over the human M2 receptor has been demonstrated using radioligand binding studies. It has a rapid onset of action as evidenced by observed receptor association/dissociation kinetic parameters and the onset of action after inhalation in clinical studies.

The long duration of action can be partly attributed to sustained concentrations of active substance in the lung as reflected by the prolonged terminal elimination half-life of glycopyrronium after inhalation via the Seebri Breezhaler inhaler in contrast to the half life after intravenous administration (see section 5.2).

Pharmacodynamic effects
The clinical Phase III development programme included two phase III studies: a 6-month placebo-controlled study and a 12-month placebo and active-controlled (open label tiotropium 18 micrograms once daily) study, both in patients with clinical diagnosis of moderate to severe COPD.

Effects on lung function
Seebri Breezhaler 50 micrograms once daily provided consistently statistically significant improvement in lung function (forced expiratory volume in one second, FEV1, forced vital capacity, FVC, and inspiratory capacity, IC) in a number of clinical studies. In phase III studies, bronchodilator effects were seen within 5 minutes after the first dose and were maintained over the 24-hour dosing interval from the first dose. There was no attenuation of the bronchodilator effect over time in the 6- and 12-month studies. The magnitude of the effect was dependent on the degree of reversibility of airflow limitation at baseline (tested by administration of a short-acting muscarinic antagonist bronchodilator): Patients with the lowest degree of reversibility at baseline (<5%) generally exhibited a lower bronchodilator response than patients with a higher degree of reversibility at baseline (≥5%).
At 12 weeks (primary endpoint), Seebri Breezhaler increased trough FEV1 by 72 ml in patients with the lowest degree of reversibility (<5%) and by 113 ml in those patients with a higher degree of reversibility at baseline (≥5%) compared to placebo (both p<0.05).

SEE API FEB22 V2                                                                   REF EU SmPC Nov2021 In the 6-month study, Seebri Breezhaler increased FEV1 after the first dose with an improvement of 93 ml within 5 minutes and 144 ml within 15 minutes of dosing, compared to placebo (both p<0.001).
In the 12-month study, the improvements were 87 ml at 5 minutes and 143 ml at 15 minutes (both p<0.001). In the 12-month study, Seebri Breezhaler produced statistically significant improvements in FEV1 compared to tiotropium in the first 4 hours after dosing on day 1 and at week 26, and numerically greater values for FEV1 in the first 4 hours after dosing than tiotropium at week 12 and week 52.

The values for FEV1 at the end of the dosing interval (24 h post dose) were similar between the first dose and those seen after 1 year of dosing. At 12 weeks (primary endpoint), Seebri Breezhaler increased trough FEV1 by 108 ml in the 6-month study and by 97 ml in the 12-month study compared to placebo (both p<0.001). In the 12-month study, the improvement versus placebo for tiotropium was 83 ml (p<0.001).

Symptomatic outcomes
Seebri Breezhaler administered at 50 micrograms once daily statistically significantly reduced breathlessness as evaluated by the Transitional Dyspnoea Index (TDI). In a pooled analysis of the 6- and 12-month pivotal studies a statistically significantly higher percentage of patients receiving Seebri Breezhaler responded with a 1 point or greater improvement in the TDI focal score at week 26 compared to placebo (58.4% and 46.4% respectively, p<0.001). These findings were similar to those seen in patients receiving tiotropium, 53.4% of whom responded with 1 point or greater improvement (p=0.009 compared to placebo).

Seebri Breezhaler once daily has also shown a statistically significant effect on health-related quality of life measured using the St. George’s Respiratory Questionnaire (SGRQ). A pooled analysis of the 6- and 12-month pivotal studies found a statistically significantly higher percentage of patients receiving Seebri Breezhaler responded with a 4 point or greater improvement in SGRQ compared to placebo at week 26 (57.8% and 47.6% respectively, p<0.001). For patients receiving tiotropium, 61.0% responded with a 4 point or greater improvement in SGRQ (p=0.004 compared to placebo).

COPD exacerbations reduction
COPD exacerbation data was collected in the 6- and 12–month pivotal studies. In both studies, the percentage of patients experiencing a moderate or severe exacerbation (defined as requiring treatment with systemic corticosteroids and/or antibiotics or hospitalisation) was reduced. In the 6-month study, the percentage of patients experiencing a moderate or severe exacerbation was 17.5% for Seebri Breezhaler and 24.2% for placebo (Hazard ratio: 0.69, p=0.023), and in the 12-month study it was 32.8% for Seebri Breezhaler and 40.2% for placebo (Hazard ratio: 0.66, p=0.001). In a pooled analysis of the first 6 months of treatment in the 6- and 12-month studies, compared to placebo Seebri Breezhaler statistically significantly prolonged time to first moderate or severe exacerbation and reduced the rate of moderate or severe COPD exacerbations (0.53 exacerbations/year versus 0.77exacerbations /year, p<0.001). The pooled analysis also showed fewer patients treated with Seebri Breezhaler than with placebo experienced an exacerbation requiring hospitalisation (1.7% versus 4.2%, p=0.003).

Other effects
Seebri Breezhaler once daily statistically significantly reduced the use of rescue medication (salbutamol) by 0.46 puffs per day (p=0.005) over 26 weeks and by 0.37 puffs per day (p=0.039) over 52 weeks, compared to placebo for the 6- and 12-month studies, respectively.

SEE API FEB22 V2                                                                  REF EU SmPC Nov2021 In a 3-week study where exercise tolerance was tested via cycle ergometer at submaximal (80%) workload (submaximal exercise tolerance test), Seebri Breezhaler, dosed in the morning, reduced dynamic hyperinflation and improved the length of time exercise could be maintained from the first dose onwards. On the first day of treatment inspiratory capacity under exercise was improved by 230 ml and exercise endurance time was improved by 43 seconds (an increase of 10%) compared to placebo. After three weeks of treatment the improvement in inspiratory capacity with Seebri Breezhaler was similar to the first day (200 ml), exercise endurance time however had increased by 89 seconds (an increase of 21%) compared to placebo. Seebri Breezhaler was found to decrease dyspnoea and leg discomfort when exercising as measured using Borg scales. Seebri Breezhaler also reduced dyspnoea at rest measured using the Transitional Dyspnoea Index.

Secondary pharmacodynamic effects
No change in mean heart rate or QTc interval was observed with Seebri Breezhaler in doses up to 176 micrograms in COPD patients. In a thorough QT study in 73 healthy volunteers, a single inhaled dose of glycopyrronium 352 micrograms (8 times the therapeutic dose) did not prolong the QTc interval and slightly reduced heart rate (maximal effect -5.9 bpm; average effect over 24 hours -2.8 bpm) when compared to placebo. The effect on heart rate and QTc interval of
150 micrograms glycopyrronium bromide (equivalent to 120 micrograms glycopyrronium) administered intravenously was investigated in young healthy subjects. Peak exposures (Cmax) about 50-fold higher than after inhalation of glycopyrronium 50 micrograms at steady state were achieved and did not result in tachycardia or QTc prolongation. A slight reduction in heart rate (mean difference over 24 h -2 bpm when compared to placebo), which is a known effect of low exposures to anticholinergic compounds in young healthy subjects, was observed.

Pharmacokinetic Properties

5.2   Pharmacokinetic properties
Absorption
Following oral inhalation using the Seebri Breezhaler inhaler, glycopyrronium was rapidly absorbed and reached peak plasma levels at 5 minutes post dose.

The absolute bioavailability of glycopyrromium inhaled via Seebri Breezhaler was estimated to be about 45% of the delivered dose. About 90% of systemic exposure following inhalation is due to lung absorption and 10% is due to gastrointestinal absorption.

In patients with COPD, pharmacokinetic steady-state of glycopyrronium was reached within one week of the start of treatment. The steady-state mean peak and trough plasma concentrations of glycopyrronium for a 50 micrograms once-daily dosing regimen were 166 picograms/ml and 8 picograms/ml, respectively. Steady-state exposure to glycopyrronium (AUC over the 24-hour dosing interval) was about 1.4- to 1.7-fold higher than after the first dose.

Distribution
After intravenous dosing, the steady-state volume of distribution of glycopyrronium was 83 litres and the volume of distribution in the terminal phase was 376 litres. The apparent volume of distribution in the terminal phase following inhalation was almost 20-fold larger, which reflects the much slower elimination after inhalation. The in vitro human plasma protein binding of glycopyrronium was 38% to 41% at concentrations of 1 to 10 nanograms/ml.


SEE API FEB22 V2                                                                 REF EU SmPC Nov2021 Biotransformation
In vitro metabolism studies showed consistent metabolic pathways for glycopyrronium bromide between animals and humans. Hydroxylation resulting in a variety of mono-and bis-hydroxylated metabolites and direct hydrolysis resulting in the formation of a carboxylic acid derivative (M9) were seen. In vivo, M9 is formed from the swallowed dose fraction of inhaled glycopyrronium bromide.
Glucuronide and/or sulfate conjugates of glycopyrronium were found in urine of humans after repeated inhalation, accounting for about 3% of the dose.

Multiple CYP isoenzymes contribute to the oxidative biotransformation of glycopyrronium. Inhibition or induction of the metabolism of glycopyrronium is unlikely to result in a relevant change of systemic exposure to the active substance.

In vitro inhibition studies demonstrated that glycopyrronium bromide has no relevant capacity to inhibit CYP1A2, CYP2A6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 or CYP3A4/5, the efflux transporters MDR1, MRP2 or MXR, and the uptake transporters OCT1 or OCT2. In vitro enzyme induction studies did not indicate a clinically relevant induction by glycopyrronium bromide for cytochrome P450 isoenzymes, or for UGT1A1 and the transporters MDR1 and MRP2.

Elimination
After intravenous administration of [3H]-labelled glycopyrronium bromide to humans, the mean urinary excretion of radioactivity in 48 hours amounted to 85% of the dose. A further 5% of the dose was found in the bile.

Renal elimination of parent drug accounts for about 60 to 70% of total clearance of systemically available glycopyrronium whereas non-renal clearance processes account for about 30 to 40%. Biliary clearance contributes to the non-renal clearance, but the majority of non-renal clearance is thought to be due to metabolism.

Mean renal clearance of glycopyrronium following inhalation was in the range of 17.4 and 24.4 litres/h. Active tubular secretion contributes to the renal elimination of glycopyrronium. Up to
23% of the delivered dose was found in urine as parent drug.

Glycopyrronium plasma concentrations declined in a multi-phasic manner. The mean terminal elimination half-life was much longer after inhalation (33 to 57 hours) than after intravenous (6.2 hours) and oral (2.8 hours) administration. The elimination pattern suggests sustained lung absorption and/or transfer of glycopyrronium into the systemic circulation at and beyond 24 hours after inhalation.

Linearity/non-linearity
In COPD patients both systemic exposure and total urinary excretion of glycopyrronium at pharmacokinetic steady state increased about dose-proportionally over the dose range of 44 to 176 micrograms.

Special populations
A population pharmacokinetic analysis of data in COPD patients identified body weight and age as factors contributing to inter-patient variability in systemic exposure. Seebri Breezhaler 50 micrograms once daily can be safely used in all age and body weight groups.

Gender, smoking status and baseline FEV1 had no apparent effect on systemic exposure.
SEE API FEB22 V2                                                                 REF EU SmPC Nov2021 There were no major differences in total systemic exposure (AUC) between Japanese and Caucasian subjects following inhalation of glycopyrronium bromide. Insufficient pharmacokinetic data is available for other ethnicities or races.

Patients with hepatic impairment
Clinical studies have not been conducted in patients with hepatic impairment. Glycopyrronium is cleared predominantly from the systemic circulation by renal excretion. Impairment of the hepatic metabolism of glycopyrronium is not thought to result in a clinically relevant increase of systemic exposure.

Patients with renal impairment
Renal impairment has an impact on the systemic exposure to glycopyrronium bromide. A moderate mean increase in total systemic exposure (AUClast) of up to 1.4-fold was seen in subjects with mild and moderate renal impairment and up to 2.2-fold in subjects with severe renal impairment and end-stage renal disease. In COPD patients with mild and moderate renal impairment (estimated glomerular filtration rate, eGFR ≥30 ml/min/1.73 m2) Seebri Breezhaler can be used at the recommended dose. In patients with severe renal impairment (eGFR <30 ml/min/1.73 m2), including those with end-stage renal disease requiring dialysis, Seebri Breezhaler should only be used if the expected benefit outweighs the potential risk (see section 4.4).