L-?Cysteinyl-?L-?cysteinyl-?L-?α-?glutamyl-?L-?tyrosyl-?L-?cysteinyl-?L-?cysteinyl-?L-?asparaginyl-?L-?prolyl-?L-?alanyl-?L-?cysteinyl-?L-?threonylglycyl-?L-?cysteinyl-L-?Tyrosine-d3 is a derivative of Linaclotide (L465880), a guanylate cyclase-C agonist currently being studied in Phase 3 trials for the treatment of irritable bowel syndrome with constipation.