CR665 (H-
D-Phe-
D-Phe-
D-Nle-
D-Arg-NH-4-Picolyl), also known by the previous developmental code names FE-200665 and JNJ-38488502, is an all
D-amino acid
peptide
Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty am ...
that acts as a peripherally restricted
κ-opioid receptor
The κ-opioid receptor or kappa opioid receptor, abbreviated KOR or KOP for its ligand ketazocine, is a G protein-coupled receptor that in humans is encoded by the ''OPRK1'' gene. The KOR is coupled to the G protein Gi/G0 and is one of four re ...
agonist. The selectivity for FE 200665 is 1/16,900/84,600 for the human κ,
μ, and
δ opioid receptors, respectively. The dose of FE 200665 required to produce motor impairment (measure of
CNS penetration) was 548 times higher than the dose required for
antinociceptive activity.
It is being developed for use by
Cara Therapeutics under the code name CR665.
A small,
blinded study was done in healthy humans to determine the analgesic effects. CR665 was dosed at 0.36 mg/kg
I.V., and was compared to 15 mg
oxycodone
Oxycodone, sold under the brand name Roxicodone and OxyContin (which is the extended-release form) among others, is a semi-synthetic opioid used medically for the treatment of moderate to severe pain. It is highly addictive and is a commonly ...
orally. CR665 had analgesic effects on visceral pain, but produced a
hyperalgesic response in a skin pinch test.
See also
*
Difelikefalin (CR845)
References
Analgesics
Kappa-opioid receptor agonists
Opioid peptides
Peripherally selective drugs
{{analgesic-stub