|Pharmacotherapeutic group: Drugs for obstructive airway diseases, anticholinergics, ATC code: R03BB06|
Mechanism of actionSeebri Breezhaler 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 effectsThe 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 functionSeebri Breezhaler 44 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).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 outcomesSeebri Breezhaler administered at 44 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 reductionCOPD exacerbation data was collected in the 6- and 12month 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 0.77 exacerbations /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 effectsSeebri 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.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 effectsNo 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 44 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.
Paediatric populationThe European Medicines Agency has waived the obligation to submit the results of studies with Seebri Breezhaler in all subsets of the paediatric population in COPD (see section 4.2 for information on paediatric use).