Multivalent dual pharmacology muscarinic antagonist and β₂ agonist (MABA) molecules for the treatment of COPD

ADME properties of CHF6366, a novel bi-functional M3-Muscarinic receptor antagonist and ß-2 adrenoceptor agonist (MABA) radiolabeled at both functional moieties

CHF6366, a dual action β₂-receptor agonist and M₃-muscarinic receptor antagonist developed for chronic obstructive pulmonary disease (COPD), was [¹⁴C]-radiolabeled on the two different functional moieties of the molecule (either aminobutanolic or carbamate) to characterize its ADME profile following intravenous (IV), intratracheal (IT) and oral (PO) administration.A very low oral bioavailability and a good balance between absorption and lung retention after IT administration were observed, together with a rapid distribution throughout the body and a complete metabolic transformation of the parent drug without relevant gender difference.CHF6366 was observed fully hydrolyzed to alcohol (CHF6387) and carboxylic acid (CHF6361) in plasma and urine after IV and IT administration, and mainly unchanged in feces only after oral administration. An important number of metabolites containing aminobutanolic moiety was excreted via urine, whereas carbamate-containing derivatives were excreted mainly by bile.The major metabolic routes of the alcoholic moiety (CHF6387) included isomerization (Ma7), conjugation with glucuronic acid and dehydrogenation, while the carboxylic acid moiety (CHF6361) was mainly metabolized through oxidation, glucuronide conjugation and, in both pathways, combinations of those metabolic reactions.No major differences arose also from in vitro metabolism profiles investigated using liver microsomes and hepatocytes of different species.

Discovery of a novel class of inhaled dual pharmacology muscarinic antagonist and β2 agonist (MABA) for the treatment of chronic obstructive pulmonary disease (COPD)

The targeting of both the muscarinic and β-adrenergic pathways is a well validated therapeutic approach for the treatment of chronic obstructive pulmonary disease (COPD). In this communication we report our effort to incorporate two pharmacologies into a single chemical entity, whose characteristic must be suitable for a once daily inhaled administration. Contextually, we aimed at a locally acting therapy with limited systemic absorption to minimize side effects. Our lung-tailored design of bifunctional compounds that combine the muscarinic and β-adrenergic pharmacologies by the elaboration of the muscarinic inhibitor 7, successfully led to the potent, pharmacologically balanced muscarinic antagonist and β₂ agonist (MABA) 13.

Investigational beta-2 adrenergic agonists for the treatment of chronic obstructive pulmonary disease

INTRODUCTION

Long-acting bronchodilators are pivotal in the therapeutic management of COPD patients with moderate-to-severe airflow obstruction. New ultra-long-acting β2-agnoists (ultra-LABAs) have been developed, some of which have been licensed for use as monotherapy and/or in combination with other bronchodilators or inhaled corticosteroids, for use in COPD patients with persistent symptoms and worsening airflow limitation. These new agents are faster in onset and have a prolonged duration of action, with a similar safety profile to the traditional twice-daily bronchodilators which may have an impact on patient concordance. Areas covered: A number of these ultra-LABAs are still under development and bi-functional hybrid molecules containing regions functioning as β2-agonists, and as muscarinic agonists (MABAs) has been developed. This review summarizes these (excluding the licensed ultra-LABAs) with attention on phase II studies data available to-date on their pharmacological profiles, clinical efficacy and safety, and future perspectives. Expert opinion: Despite all the new agents' available, the challenges that persist include any differences in efficacy and safety between the various possible LAMA/LABA combinations, relative advantages of MABAs over fixed-dose LAMA/LABAs, and the impact of these new molecules in terms of long term safety, especially in certain populations in co-morbidities frequently associated with COPD.

Pharmacologic characterization of GSK-961081 (TD-5959), a first-in-class inhaled bifunctional bronchodilator possessing muscarinic receptor antagonist and β2-adrenoceptor agonist properties

The objective of the present studies was to characterize the pharmacologic properties of GSK-961081 [TD-5959; (R)-1-(3-((2-chloro-4-(((2-hydroxy-2-(8-hydroxy-2-oxo-1,2-dihydroquinolin-5-yl)ethyl)amino)methyl)-5-methoxyphenyl)amino)-3-oxopropyl) piperidin-4-yl [1,1'-biphenyl]-2-ylcarbamate], a novel first-in-class inhaled bifunctional compound possessing both muscarinic antagonist (MA) and β2-adrenoceptor agonist (BA) properties (MABA). In competition radioligand binding studies at human recombinant receptors, GSK-961081 displayed high affinity for hM2 (Ki = 1.4 nM), hM3 muscarinic receptors (Ki = 1.3 nM) and hβ2-adrenoceptors (Ki = 3.7 nM). GSK-961081 behaved as a potent hβ2-adrenoceptor agonist (EC50 = 0.29 nM for stimulation of cAMP levels) with 440- and 320-fold functional selectivity over hβ1- and hβ3-adrenoceptors, respectively. In guinea pig isolated tracheal tissues, GSK-961081 produced smooth muscle relaxation through MA (EC50 = 50.2 nM), BA (EC50=24.6 nM), and MABA (EC50 = 11 nM) mechanisms. In the guinea pig bronchoprotection assay, inhaled GSK-961081 produced potent, dose-dependent inhibition of bronchoconstrictor responses via MA (ED50 = 33.9 µg/ml), BA (ED50 = 14.1 µg/ml), and MABA (ED50 = 6.4 µg/ml) mechanisms. Significant bronchoprotective effects of GSK-961081 were evident in guinea pigs via MA, BA, and MABA mechanisms for up to 7 days after dosing. The lung selectivity index of GSK-961081 in guinea pigs was 55- to 110-fold greater than that of tiotropium with respect to systemic antimuscarinic antisialagogue effects and was 10-fold greater than that of salmeterol with respect to systemic β2-adrenoceptor hypotensive effects. These preclinical findings studies suggest that GSK-961081 has the potential to be a promising next-generation inhaled lung-selective bronchodilator for the treatment of airway diseases, including chronic obstructive pulmonary disease.

Considerations for new dual-acting bronchodilator treatments for chronic obstructive pulmonary disease

Current guidelines recommend treatment with one or more bronchodilators for chronic obstructive pulmonary disease (COPD) patients. Combination therapy with long-acting muscarinic antagonists (LAMA) and long-acting β2-agonists (LABA) should be recommended in patients who are not fully controlled with one of them. In this article, two closely related approaches to provide long-acting treatments are compared: the LABA/LAMA fixed-dose combination therapy, and the dual-acting muscarinic receptor antagonist and β2-adrenoceptor agonist (MABA). The author in that study concludes that both approaches have been shown to provide clinically enhanced bronchodilator activity that is superior to that offered by current standard treatment. LAMA/LABA fixed-dose combinations are expected to become a new standard in the treatment of COPD. It is important to know the characteristics of the different LAMA or LABA, the inhalation device and the duration of action, because diversity can help to personalize the treatment. Dose-finding studies are required. It is also required to investigate the existence of pharmacodynamics or pharmacokinetic interactions between the components as well as the safety profile. MABA represent an alternative to these combinations, but there is little clinical data yet reported. They have the potential to act as a useful platform for the development of triple therapy in one inhaler.

An update on bronchodilators in Phase I and II clinical trials

INTRODUCTION

Inhaled bronchodilators are the mainstay of the current management of COPD at all stages of the disease, and are critical in the symptomatic management of asthma. Therefore, there is still considerable interest in finding novel classes of broncholytic drugs or, at least, in improving the existing classes of bronchodilator.

AREAS COVERED

This review paper mainly focuses on bronchodilators that are in Phase I and II clinical trials.

EXPERT OPINION

To date, finding new classes of bronchodilators has proved difficult. Consequently, many research groups have sought to improve the existing classes of bronchodytic drugs. The majority of programs in development for novel bronchodilators are focused on developing new ligands that interact with β(2)-adrenoceptors and/or muscarinic acetylcholine receptors in a manner that enhances their bronchodilator effectiveness and duration of action, which allows only one administration per day, although the twice-daily dosing of bronchodilators is still considered a useful approach to the symptomatic treatment of COPD, and improving their safety profiles. Moreover, the current opinion is that it is advantageous to develop inhalers containing combinations of long-acting bronchodilator drugs in an attempt to simplify treatment regimes as much as possible. Another goal is to develop novel combinations of one or two classes of long-acting bronchodilators along with inhaled corticosteroids.