SBI-553 is an experimental drug that binds to an intracellular pocket of neurotensin receptor 1 (NTSR1). It acts as a β-arrestin biased positive allosteric modulator and changes NTSR1 G protein preference, biasing NTSR1 away from Gq/11 and toward alternative G protein coupling. It has analgesic effects in animal studies, but importantly also reduces addictive behaviors produced by stimulants and μ-opioid receptor agonists in animal models, suggesting it may be useful as a novel agent for pain relief but which lacks the abuse liability of many currently used analgesic drugs, and may even reduce the potential for addiction when used alongside older analgesics. A closely related derivative, SBI-810, has superior analgesic effects and may be more likely to be developed for clinical applications.
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