An orally bioavailable antagonist of the prostaglandin E receptor subtype 4 (EP4), with potential analgesic, immunomodulating and antineoplastic activities. Upon administration of the EP4 receptor antagonist AAT-007, this agent selectively binds to and inhibits the binding of prostaglandin E2 (PGE2) and prevents the activation of the EP4 receptor. This inhibits PGE2-EP4 receptor-mediated signaling and prevents proliferation in tumor cells in which the PGE2-EP4 signaling pathway is over-activated. In addition, EP4 receptor inhibition modulates the immune system by preventing both interleukin-23 (IL-23) production and the IL-23-mediated expansion of Th17 cells. As EP4 is expressed by peripheral sensory neurons, blockade of EP4-mediated signaling may induce an analgesic effect. EP4, a prostanoid receptor subtype, is a G protein-coupled receptor that is expressed in certain types of cancers; it promotes tumor cell proliferation and invasion.