Patent ID: 8628750

Claim:
A compound or conjugate, or a pharmaceutically acceptable salt or ester thereof, comprising a ligand for the chemokine receptor CXCR4 and a detectable label, the ligand having a binding affinity for the CXCR4 receptor, measured as IC 50 in the presence of 125 I-CPCR4, of 250 nM or lower, wherein the ligand comprises a cyclic oligopeptide moiety, wherein the cyclic oligopeptide moiety is: cyclo[D-Tyr/(Me)D-Tyr-B-Arg/(Me)Arg-Z-(Ala) n -X] wherein: B is selected from the group consisting of substituted Arg, substituted Orn, Cit or substituted Cit, His or substituted His, Phe or substituted Phe, Lys or substituted Lys, 2,3-diaminopropionic acid (Dap) or substituted Dap, and 2,4-diaminobutyric acid (Dab) or substituted Dab; provided that if B is substituted with methyl, it is followed by Arg; Z is an amino acid containing an aromatic group in its side chain; X is selected from the group consisting of Ala or substituted Ala, Gly or substituted Gly, and Dap or substituted Dap; n is 1 or 0, provided that n is 1 only when B is Arg and Z is L-3-(2-naphthyl)alanine (Nal).