HS665 is a drug which acts as a potent and selective ú-opioid receptor agonist, and has analgesic effects in animal studies. HS665 is not an agonist for the mu receptor, leading to less potential for abuse.
The structure of HS665 is a close analog of an existing compound called RU-24213. RU-24213 has D2-agonist and KOR antagonist pharmacology.