Ultra-LABAs for the treatment of asthma

The term ultra-LABA indicates once-daily β2-AR agonists (abediterol, indacaterol, olodaterol and vilanterol) that are single enantiomers of the (R)-configuration. All have a near full-agonist profile at human β2-AR. They can be prescribed in asthmatics only when associated with an with ICS, although further confirmations need to clarify what really these agents add if used in association to ICS and in what asthmatic patients this association may have more value. They are also under development in triple inhalers that include an ultra-LABA, a LAMA and an ICS. The once-daily posology might increase adherence in long-term treatment of asthma but superiority to twice-daily LABAs has not yet been fully demonstrated. In any case, still no ultra-LABA can be recommended as preferred.

Abediterol (LAS100977), an inhaled long-acting β2-adrenoceptor agonist, has a fast association rate and long residence time at receptor

This study describes the association rate and residence time of abediterol, a novel long-acting β₂-adrenoceptor agonist (LABA) in Phase II development for treatment of asthma and COPD, in comparison with indacaterol, olodaterol, vilanterol and salmeterol, for both human β₁- and β₂-adrenoceptors. Abediterol association and dissociation rates were monitored directly by using its tritiated form. Moreover, association was determined indirectly using experimental K_i and k_off obtained from assays performed with unlabelled compound. Dissociation was also studied indirectly by measuring the association rate of ³H-CGP12177 to beta adrenoceptors previously occupied by unlabelled compounds. Abediterol shows a fast association for the β₂-adrenoceptor (k_on 1.4 × 10⁷ ± 1.8 × 10⁶M^-1min^-1) while its dissociation rate is between 30 and 64 times slower than that of the reference LABA compounds tested, with a residence time of 91.3 ± 13.3min (measured directly) and 185.5 ± 7.5min (measured indirectly). Abediterol shows kinetic selectivity for the β₂- over the β₁-adrenoceptor, with a dissociation rate from the β₁-adrenoceptor similar to the other LABA compounds tested. In conclusion, abediterol is a potent LABA with a fast association rate and a long residence time at β₂-adrenoceptors. These data are in agreement with the onset and duration of action of abediterol shown in humans.

Abediterol (LAS100977), a novel long-acting β2-agonist: efficacy, safety and tolerability in persistent asthma

BACKGROUND

Abediterol (LAS100977) is a novel, long-acting β2-agonist, in development for the once-daily treatment of asthma in combination with mometasone. Here we report the results of a Phase IIa trial of single doses of abediterol added to ongoing maintenance therapy (inhaled corticosteroids) in patients with persistent mild-to-moderate asthma.

METHODS

This was a randomised, double-blind, placebo- and active-comparator-controlled, five-way crossover study. Male patients (18-70 years) with a clinical diagnosis of persistent asthma received abediterol (5, 10 and 25 μg), salmeterol and placebo, on top of ongoing maintenance therapy. Lung function was determined using spirometry and whole body plethysmography. The primary efficacy endpoint was change from baseline in trough forced expiratory volume in 1 s (FEV1) after a single dose.

RESULTS

All three abediterol doses induced statistically significant increases in trough FEV1 vs placebo and salmeterol. Improvements in other lung function parameters were also statistically significantly greater with all abediterol doses vs both placebo (p < 0.0001) and salmeterol (p < 0.05) than the first assessment at 5 min post-dose. These improvements were sustained to 36 h post-dose. The profile of treatment-emergent adverse events judged as related to abediterol was consistent with that seen after adrenergic stimulation and occurred exclusively in patients who received abediterol 10 μg or 25 μg.

CONCLUSIONS

This first-in-patient study revealed the potent, rapid and long-acting bronchodilatory effect of abediterol in patients with persistent mild-to-moderate asthma together with an overall good safety and tolerability profile. Further studies are now underway to establish the optimal efficacy-safety-tolerability profile for this compound.