Discovery of olodaterol, a novel inhaled β2-adrenoceptor agonist with a 24h bronchodilatory efficacy

A multivalent approach to the discovery of long-acting β(2)-adrenoceptor agonists for the treatment of asthma and COPD

A multivalent approach was applied to the design of long-acting inhaled β(2)-adrenoceptor agonists. A series of dimeric arylethanolamines based on the short acting β(2)-adrenoceptor agonist albuterol were prepared, varying the nature and length of the linker between the basic nitrogens. None of the C(2)-symmetric dimers demonstrated increased potency, however dimer 5j, derived from 4-phenethylamine, was found to have increased binding potency in vitro relative to the parent monomer. Optimization of this structure led to the identification of 22 (milveterol) which demonstrates high potency in vitro and long duration of action in a guinea pig model of bronchoprotection.

From libraries to candidate: the discovery of new ultra long-acting dibasic β₂-adrenoceptor agonists

Libraries of dibasic compounds designed around the molecular scaffold of the DA(2)/β(2) dual agonist sibenadet (Viozan™) have yielded a number of promising starting points that have been further optimised into novel potent and selective target molecules with required pharmacokinetic properties. From a shortlist, 31 was discovered as a novel, high potency, and highly efficacious β(2)-agonist with high selectivity and a duration of action commensurable with once daily dosing.

24-hour bronchodilation following a single dose of the novel β(2)-agonist olodaterol in COPD

BACKGROUND

Current guidelines recommend long-acting bronchodilators as maintenance therapy in COPD when symptoms are not adequately controlled with short-acting agents. Olodaterol is a novel long-acting β(2)-adrenoceptor agonist with a pre-clinical profile that suggests 24-h bronchodilation may be achieved with once-daily administration.

OBJECTIVE

To assess dose- and time-response in terms of bronchodilator efficacy, and to evaluate pharmacokinetics, safety and tolerability of single doses of olodaterol administered via Respimat(®) Soft Mist™ Inhaler in COPD patients.

METHODS

A single-center, double-blind, placebo-controlled, 5-way crossover study including 24-h spirometry (FEV(1), FVC), safety, tolerability and pharmacokinetics (in a subset of patients) following dosing of olodaterol 2 μg, 5 μg, 10 μg and 20 μg; the washout period between test-days was at least 14 days. Primary endpoint of the study was the 24-h post-dosing FEV(1). Patients participating in the pharmacokinetic assessments continued in an open-label extension phase to establish pharmacokinetics of olodaterol 40 μg.

RESULTS

36 patients were assigned to treatment; mean baseline prebronchodilator FEV(1) was 1.01 L (37% predicted normal). All doses of olodaterol provided significantly greater bronchodilation compared to placebo in 24-h FEV(1) post-dose (p < 0.001); a clear dose-response relationship was observed, with values ranging from 0.070 L for olodaterol 2 μg to 0.119 L for olodaterol 20 μg. Similarly, olodaterol was superior to placebo (p < 0.001) in peak FEV(1) (0.121 L to 0.213 L) and average FEV(1) both during the daytime (0-12 h; ranging from 0.099 L to 0.184 L) and night-time (12-24 h; ranging from 0.074 L to 0.141 L). FVC results were consistent with those observed for FEV(1). Pharmacokinetic evaluation of the peak plasma concentrations and renal excretion suggested no obvious deviation from dose-proportionality over the investigated dose range of 2 μg-40 μg; in most patients, no plasma levels could be detected following the 2 μg dose. All treatments were well tolerated with no apparent dose relation in terms of adverse events.

CONCLUSIONS

Olodaterol appears to be a promising long-acting β(2)-adrenoceptor agonist,with bronchodilation maintained over 24 h that offers an opportunity for once-daily dosing in patients who require maintenance bronchodilator therapy for the management of COPD symptoms.

β(2) -adrenoceptor agonists: current and future direction

Despite the passionate debate over the use of β(2) -adrenoceptor agonists in the treatment of airway disorders, these agents are still central in the symptomatic management of asthma and COPD. A variety of β(2) -adrenoceptor agonists with long half-lives, also called ultra long-acting β(2) -adrenoceptor agonists (ultra-LABAs; indacaterol, olodaterol, vilanterol, carmoterol, LAS100977 and PF-610355) are currently under development with the hopes of achieving once-daily dosing. It is likely that the once-daily dosing of a bronchodilator would be a significant convenience and probably a compliance-enhancing advantage, leading to improved overall clinical outcomes. As combination therapy with an inhaled corticosteroid (ICS) and a LABA is important for treating patients suffering from asthma, and a combination with an inhaled long-acting antimuscarinic agent (LAMA) is important for treating COPD patients whose conditions are not sufficiently controlled by monotherapy with a β(2) -adrenoceptor agonist, some novel once-daily combinations of LABAs and ICSs or LAMAs are under development.

Long-acting beta-agonists in the management of chronic obstructive pulmonary disease: current and future agents

Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation and debilitating symptoms. For patients with moderate-to-severe COPD, long-acting bronchodilators are the mainstay of therapy; as symptoms progress, guidelines recommend combining bronchodilators from different classes to improve efficacy. Inhaled long-acting β2-agonists (LABAs) have been licensed for the treatment of COPD since the late 1990s and include formoterol and salmeterol. They improve lung function, symptoms of breathlessness and exercise limitation, health-related quality of life, and may reduce the rate of exacerbations, although not all patients achieve clinically meaningful improvements in symptoms or health related quality of life. In addition, LABAs have an acceptable safety profile, and are not associated with an increased risk of respiratory mortality, although adverse effects such as palpitations and tremor may limit the dose that can be tolerated. Formoterol and salmeterol have 12-hour durations of action; however, sustained bronchodilation is desirable in COPD. A LABA with a 24-hour duration of action could provide improvements in efficacy, compared with twice-daily LABAs, and the once-daily dosing regimen could help improve compliance. It is also desirable that a new LABA should demonstrate fast onset of action, and a safety profile at least comparable to existing LABAs.A number of novel LABAs with once-daily profiles are in development which may be judged against these criteria. Indacaterol, a LABA with a 24-hour duration of bronchodilation and fast onset of action, is the most advanced of these. Preliminary results from large clinical trials suggest indacaterol improves lung function compared with placebo and other long-acting bronchodilators. Other LABAs with a 24-hour duration of bronchodilation include carmoterol, vilanterol trifenatate and oldaterol, with early results indicating potential for once-daily dosing in humans.The introduction of once-daily LABAs also provides the opportunity to develop combination inhalers of two or more classes of once-daily long-acting bronchodilators, which may be advantageous for COPD patients through simplification of treatment regimens as well as improvements in efficacy. Once-daily LABAs used both alone and in combination with long-acting muscarinic antagonists represent a promising advance in the treatment of COPD, and are likely to further improve outcomes for patients.

Inhalation by design: novel ultra-long-acting β(2)-adrenoreceptor agonists for inhaled once-daily treatment of asthma and chronic obstructive pulmonary disease that utilize a sulfonamide agonist headgroup

A novel series of potent and selective sulfonamide derived β(2)-adrenoreceptor agonists are described that exhibit potential as inhaled ultra-long-acting bronchodilators for the treatment of asthma and chronic obstructive pulmonary disease. Analogues from this series mediate very long-lasting smooth muscle relaxation in guinea pig tracheal strips. The sulfonamide agonist headgroup confers high levels of intrinsic crystallinity that could relate to the acidic sulfonamide motif supporting a zwitterionic form in the solid state. Optimization of pharmacokinetic properties was achieved through targeted introduction of a phenolic moiety to support rapid phase II clearance, thereby minimizing systemic exposure following inhalation and reducing systemically mediated adverse events. Compound 38 (PF-610355) is identified as a clinical candidate from this series, with in vivo duration of action studies confirming its potential for once-daily use in humans. Compound 38 is currently in advanced phase II clinical studies.