The design, synthesis, and structure-activity relationship development of naphthalene-derived human CCR8 antagonists is described. In vitro binding assay results of these investigations are reported, critical interactions of the antagonists with CCR8 are defined, and preliminary physicochemical and pharmacokinetic data for the naphthalene scaffold are presented.

A novel series of barbituric acid derivatives were identified as selective inhibitors of alpha4beta7 MAdCAM (mucosal addressin cell adhesion molecule-1) interactions via a high throughput screening exercise. These inhibitors were optimized to submicromolar potencies in whole cell adhesion assays, retaining their selectivity over alpha4beta1 VCAM.

The identification, optimization, and structure-activity relationship (SAR) of small-molecule CCR4 antagonists is described. An initial screening hit with micromolar potency was identified that was optimized to sub-micromolar binding potency by enantiomer resolution, halogenation of the naphthalene ring, and extension of the alkyl chain linker between the central piperidine ring and the terminal aryl group. An antagonist was identified that showed good cross-reactivity against the mouse receptor and inhibited CCR4-based cell recruitment in dose-dependent fashion.

Activation of CCR8 by its ligand CCL1 may play an important role in diseases such as asthma, multiple sclerosis, and cancer. The study of small molecule CCR8 antagonists will help establish the validation of these hypotheses. We report the design, synthesis, and progress toward optimization of potent small molecule CCR8 antagonists identified from a high-throughput screen. These analogues exhibit good potency in binding and chemotaxis assays, show good selectivity versus the hERG channel, and have good eADME (early absorption, distribution, metabolism, and excretion) profiles.