Patent ID: 7481993
Filing Date: 2009-01-27
Classification: A61K

Abstract:
1. A conjugate PT comprising (a) a peptide P and (b) a targeting moiety T; wherein the peptide P contains from 4 to 20 amino acid residues, and including a complexing amino acid sequence comprising (i) a tridentate or tetradentate planar chelator containing a ligand backbone defined by a perimeter containing a single sulfur donor atom, two or three non-sulfur donor atoms, and intervening atoms between the donor atoms; and (ii) a stabilizing sidechain comprising a further donor atom, the further donor atom being covalently linked to the ligand backbone of the planar chelator through two or three intervening atoms, provided that said further donor atom is neither the nitrogen nor the oxygen atom of a peptide bond, and if said further donor atom is part of a heterocyclic ring, no more than one of the intervening atoms can be part of that ring; and (iii) a radioactive metal complexed to the donor atoms of the planar chelator, wherein A is —CO B is —SH, —NHR X is —SH, —NHR Z is —H or —CH n is 0, 1, or 2; R (pep) represents the remainder of the peptide P and its complexing amino acid sequence, respectively; provided that either (i) B is —SH; X is —NHR (ii) A is R (iii) A is R (iv) A is —CO and provided that if the targeting moiety T is a cyclic somatostatin derivative or cyclic somatostatin receptor binding peptide, then the stabilizing sidechain is not —CH 2 CH 2 CH 2 NH 2 , —CH 2 CH 2 NH 2 , —CH 2 -(4-imidazolyl), or —CH 2 CH 2 CH 2 NHC(NH)NH 2 ; and if the targeting moiety T is folate or folic acid or an analog thereof, then the stabilizing side chain is not —CH 2 COOH.