JNJ-7777120 is a drug being developed by Johnson & Johnson Pharmaceutical Research & Development which acts as a potent and selective antagonist

Receptor antagonist

A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...

 at the histamine H4 receptor. It has antiinflammatory effects, and has been demonstrated to be superior to traditional antihistamines in the treatment of pruritus (itching).