The discovery of CCR3/H1 dual antagonists with reduced hERG risk

Discovery of Novel Bicyclic Imidazolopyridine-Containing Human Urate Transporter 1 Inhibitors as Hypouricemic Drug Candidates with Improved Efficacy and Favorable Druggability

Lesinurad is a uricosuric agent for the treatment of hyperuricemia associated with gout, which was found lacking in efficacy and safety. Here, scaffold hopping and molecular hybridization were exploited to modify all the structural components of lesinurad, and 36 novel compounds bearing bicyclic imidazolopyridine core were obtained. In a mouse model of acute hyperuricemia, 29 compounds demonstrated increased serum uric acid (SUA)-reducing activity; SUA was treated with 12, 23, and 29 about fourfold lower compared with that of lesinurad. Moreover, 23 exhibited stronger URAT1 inhibition activity (IC₅₀ = 1.36 μM) than lesinurad (IC₅₀ = 5.54 μM). Additionally, 23 showed favorable safety profiles, and no obvious acute toxicity was observed in Kunming mice under a single dose of 1000 mg·kg^-1. 23 also achieved excellent pharmacokinetic properties with the oral bioavailability of 59.3%. Overall, all the results indicated that 23 is a promising drug candidate in the treatment of hyperuricemia and gout.

Applications of fluorine-containing amino acids for drug design

Fluorine-containing amino acids are becoming increasingly prominent in new drugs due to two general trends in the modern pharmaceutical industry. Firstly, the growing acceptance of peptides and modified peptides as drugs; and secondly, fluorine editing has become a prevalent protocol in drug-candidate optimization. Accordingly, fluorine-containing amino acids represent one of the more promising and rapidly developing areas of research in organic, bio-organic and medicinal chemistry. The goal of this Review article is to highlight the current state-of-the-art in this area by profiling 42 selected compounds that combine fluorine and amino acid structural elements. The compounds under discussion represent pharmaceutical drugs currently on the market, or in clinical trials as well as examples of drug-candidates that although withdrawn from development had a significant impact on the progress of medicinal chemistry and/or provided a deeper understanding of the nature and mechanism of biological action. For each compound, we present features of biological activity, a brief history of the design principles and the development of the synthetic approach, focusing on the source of tailor-made amino acid structures and fluorination methods. General aspects of the medicinal chemistry of fluorine-containing amino acids and synthetic methodology are briefly discussed.

Rodent selectivity of piperidine-4-yl-1H-indoles, a series of CC chemokine receptor-3 (CCR3) antagonists: insights from a receptor model

Rodent selectivity data of piperidine-4-yl-1H-indoles, a series of CC chemokine receptor-3 (CCR3) antagonists, are presented and discussed as part of an overall optimization effort within this lead compound class. Although attachment of an acidic moiety to the 1-position of the indole led to an overall balanced in vitro profile, in particular reducing inhibition of the hERG channel, potency on the rat and mouse receptor worsened. These findings could be rationalized in the context of a CCR3 homology model.

Early identification of hERG liability in drug discovery programs by automated patch clamp

Blockade of the cardiac ion channel coded by human ether-à-gogo-related gene (hERG) can lead to cardiac arrhythmia, which has become a major concern in drug discovery and development. Automated electrophysiological patch clamp allows assessment of hERG channel effects early in drug development to aid medicinal chemistry programs and has become routine in pharmaceutical companies. However, a number of potential sources of errors in setting up hERG channel assays by automated patch clamp can lead to misinterpretation of data or false effects being reported. This article describes protocols for automated electrophysiology screening of compound effects on the hERG channel current. Protocol details and the translation of criteria known from manual patch clamp experiments to automated patch clamp experiments to achieve good quality data are emphasized. Typical pitfalls and artifacts that may lead to misinterpretation of data are discussed. While this article focuses on hERG channel recordings using the QPatch (Sophion A/S, Copenhagen, Denmark) technology, many of the assay and protocol details given in this article can be transferred for setting up different ion channel assays by automated patch clamp and are similar on other planar patch clamp platforms.

Recent progress in the development of antagonists to the chemokine receptors CCR3 and CCR4

INTRODUCTION

The chemokine receptors CCR3 and CCR4 have been shown to be important therapeutic targets for the treatment of a variety of diseases. Although only two chemokine receptor inhibitors have been approved so far, there are numerous compounds that are in various stages of development.

AREAS COVERED

In this review article, the authors provide an update on the progress made in the identification of antagonists against the chemokine receptors CCR3 and CCR4 from 2009 to the present. The rationale of writing this review article is to cover the most important approaches to identifying antagonists to these two receptors, which could prove to be useful therapeutics in treating proinflammatory diseases.

EXPERT OPINION

Pharmaceutical companies have expended a considerable amount of money and effort to identify potent inhibitors of CCR3 and CCR4 for the treatment of asthma and atopic diseases. Although a variety of compounds have been described and several have progressed into the clinic, none have so far made it as approved drugs. There are, however, novel approaches such as mogamulizumab, a monoclonal antibody to CCR4 currently is in clinical trials for cancer and ASM8, an antisense nucleotide to CCR3, which is in Phase II clinical trials for asthma that might still prove to be successful new therapeutics.