Icalcaprant

Icalcaprant is a κ-opioid receptor antagonist which is under development for the treatment of major depressive disorder and substance-related disorders. It is taken by mouth.
It acts as a selective antagonist of the KOR. The drug is also more weakly an antagonist of the μ-opioid receptor, with about 31-fold lower affinity and 27-fold lower inhibitory potency at the MOR relative to the KOR.
It was originated by Pfizer and is under development by Cerevel Therapeutics. As of September 2022, icalcaprant is in phase 1 clinical trials for major depressive disorder and is in the preclincal stage of development for substance-related disorders.