Potent and Selective IL-4 Inhibitors with Anti-Tumor Activity

Interleukin-4 (IL-4) is an important immunoregulatory cytokine involved in T-cell maturation, B-cell activation, and macrophage polarization. Dysregulated IL-4 signaling contributes to several immune-mediated diseases such as cancer, allergic inflammation, and autoimmunity. The clinical use and indication expansion of the anti-IL-4Rα antibody dupilumab has made IL-4 signaling an attractive target for therapeutic modulation. We previously discovered a first-in-class small molecule inhibitor to the soluble cytokine IL-4, which we named Nico-52, that inhibits the soluble IL-4 cytokine with single-digit micromolar potency. Here, we determined structure-activity relationships around the Nico-52 scaffold that impact potency and selectivity and evaluated the <i>in vivo</i> anti-tumor potential of small molecule IL-4 inhibition. Improved analogs featured structural changes to the p-fluorophenyl group ranging from submicromolar to double-digit nanomolar potency. Our two most potent analogs showed selective binding to IL-4 over other related cytokines in thermal shift assays and more potent inhibition of IL-4 over IL-13 in a HEK Blue IL-4/IL-13 reporter assay. We further established that our lead analogs inhibit both type I and type II IL-4 receptor signaling. Nico-52 and an optimized lead analog exhibited favorable <i>in vitro</i> ADME/T properties, such as high stability and low cytotoxicity. Furthermore, Nico-52 and a lead analog were investigated for their tumor suppressive effects in syngeneic murine tumor models, where small-molecule IL-4 inhibition yielded significant tumor inhibition, shifted macrophage polarization, and our optimized lead analog improved animal survival. These studies show the promise of small-molecule cytokine inhibitors for IL-4 mediated processes of disease.