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

Discovery, Multiparametric Optimization, and Solid-State Driven Identification of CHF-6550, a Novel Soft Dual Pharmacology Muscarinic Antagonist and β2 Agonist (MABA) for the Inhaled Treatment of Respiratory Diseases

Clinical guidelines for COPD and asthma recommend inhaled β-adrenergic agonists, muscarinic antagonists, and, for frequent exacerbators, inhaled corticosteroids, with the challenge of combining them into a single device. The MABA (muscarinic antagonist and β2 agonist) concept has the potential to simplify this complexity while increasing the efficacy of both pharmacologies. In this article, we report the outcome of our solid-state driven back-up program that led to the discovery of the MABA compound CHF-6550. A soft drug approach was applied, aiming at high plasma protein binding and high hepatic clearance, concurrently with an early stage assessment of crystallinity through a dedicated experimental workflow. A new chemotype was identified, the diphenyl hydroxyacetic esters, able to generate crystalline material. Among this class, CHF-6550 demonstrated in vivo efficacy, suitability for dry powder inhaler development, favorable pharmacokinetics, and safety in preclinical settings and was selected as a back-up candidate, fulfilling the desired pharmacological and solid-state profile.

Designing drugs and chemical probes with the dualsteric approach

Traditionally, drugs are monovalent, targeting only one site on the protein surface. This includes orthosteric and allosteric drugs, which bind the protein at orthosteric and allosteric sites, respectively. Orthosteric drugs are good in potency, whereas allosteric drugs have better selectivity and are solutions to classically undruggable targets. However, it would be difficult to simultaneously reach high potency and selectivity when targeting only one site. Also, both kinds of monovalent drugs suffer from mutation-caused drug resistance. To overcome these obstacles, dualsteric modulators have been proposed in the past twenty years. Compared to orthosteric or allosteric drugs, dualsteric modulators are bivalent (or bitopic) with two pharmacophores. Each of the two pharmacophores bind the protein at the orthosteric and an allosteric site, which could bring the modulator with special properties beyond monovalent drugs. In this study, we comprehensively review the current development of dualsteric modulators. Our main effort reason and illustrate the aims to apply the dualsteric approach, including a "double win" of potency and selectivity, overcoming mutation-caused drug resistance, developments of function-biased modulators, and design of partial agonists. Moreover, the strengths of the dualsteric technique also led to its application outside pharmacy, including the design of highly sensitive fluorescent tracers and usage as molecular rulers. Besides, we also introduced drug targets, designing strategies, and validation methods of dualsteric modulators. Finally, we detail the conclusions and perspectives.

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.

Development and validation of a bioanalytical method for the quantification of CHF6550 and its metabolite (CHF6671) in rat plasma and lung homogenate using LC–MS/MS

A selective and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for accurate determination of CHF6550 and its main metabolite in rat plasma and lung homogenate samples. All biological samples were prepared by simple protein precipitation method using deuterated internal standards. The analytes were separated on a HSS T3 analytical column with 3.2 min run time at flow rate of 0.5 mL/min. The detection was performed on a triple-quadrupole tandem mass spectrometer equipped with positive-ion electrospray ionization by selected-reaction monitoring of the transitions at m/z 735.3 → 98.0 for CHF6550 and m/z 638.3 → 319.2 and 638.3 → 376.2 for CHF6671. The calibration curves for plasma samples were linear between 50 and 50000 pg/mL for both analytes. The calibration curves for lung homogenate samples were linear within 0.1-100 ng/mL for CHF6550 and 0.3-300 ng/mL for CHF6671. The method was successfully applied to a 4-week toxicity study.

Discovery of Clinical Candidate CHF-6366: A Novel Super-soft Dual Pharmacology Muscarinic Antagonist and β2 Agonist (MABA) for the Inhaled Treatment of Respiratory Diseases

The development of molecules embedding two distinct pharmacophores acting as muscarinic antagonists and β₂ agonists (MABAs) promises to be an excellent opportunity to reduce formulation issues and boost efficacy through cross-talk and allosteric interactions. Herein, we report the results of our drug discovery campaign aimed at improving the therapeutic index of a previous MABA series by exploiting the super soft-drug concept. The incorporation of a metabolic liability, stable at the site of administration but undergoing rapid systemic metabolism, to generate poorly active and quickly eliminated fragments was pursued. Our SAR studies yielded MABA 29, which demonstrated a balanced in vivo profile up to 24 h, high instability in plasma and the liver, as well as sustained exposure in the lung. In vitro safety and non-GLP toxicity studies supported the nomination of 29 (CHF-6366) as a clinical candidate, attesting to the successful development of a novel super-soft MABA compound.