Discovery of super soft-drug modulators of sphingosine-1-phosphate receptor 1

The oral S1PR1 agonist ponesimod demonstrated substantial efficacy in a phase II clinical trial of psoriasis. Unfortunately, systemic side effects were observed, which included lymphopenia and transient bradycardia. We sought to develop a topical soft-drug S1PR1 agonist with an improved therapeutic index. By modifying ponesimod, we discovered an ester series of S1PR agonists. To increase metabolic instability in plasma we synthesised esters described as specific substrates for paraoxonase and butyrylcholinesterases, esterases present in human plasma

Discovery of Soft-Drug Topical Tool Modulators of Sphingosine-1-phosphate Receptor 1 (S1PR1)

In order to study the role of S1PRs in inflammatory skin disease, S1PR modulators are dosed orally and topically in animal models of disease. The topical application of S1PR modulators in these models may, however, lead to systemic drug concentrations, which can complicate interpretation of the observed effects. We set out to design soft drug S1PR modulators as topical tool compounds to overcome this limitation. A fast follower approach starting from the drug ponesimod allowed the rapid development of an active phenolic series of soft drugs. The phenols were, however, chemically unstable. Protecting the phenol as an ester removed the instability and provided a compound that is converted by enzymatic hydrolysis in the skin to the phenolic soft drug species. In simple formulations, topical dosing of these S1PR modulators to mice led to micromolar skin concentrations but no detectable blood concentrations. These topical tools will allow researchers to investigate the role of S1PR in skin, without involvement of systemic S1PR biology

Identification of Morpholino Thiophenes as Novel Mycobacterium tuberculosis Inhibitors, Targeting QcrB

With the emergence of multidrug-resistant strains of <i>Mycobacterium tuberculosis</i> there is a pressing need for new oral drugs with novel mechanisms of action. Herein, we describe the identification of a novel morpholino–thiophenes (MOT) series following phenotypic screening of the Eli Lilly corporate library against <i>M. tuberculosis</i> strain H37Rv. The design, synthesis, and structure–activity relationships of a range of analogues around the confirmed actives are described. Optimized leads with potent whole cell activity against H37Rv, no cytotoxicity flags, and in vivo efficacy in an acute murine model of infection are described. Mode-of-action studies suggest that the novel scaffold targets QcrB, a subunit of the menaquinol cytochrome <i>c</i> oxidoreductase, part of the bc1-aa3-type cytochrome <i>c</i> oxidase complex that is responsible for driving oxygen-dependent respiration