Medicinal chemistry of somatostatin analogs leading to the DTPA and DOTA conjugates of the multi-receptor-ligand SOM230.

The somatostatin field has been a success story in terms of medicinal chemistry and drug discovery offering a variety of therapeutic opportunities. A rational medicinal chemistry approach capitalising on structure activity relationships has led to the discovery of SOM230, a novel, stable cyclohexapeptide somatostatin analog which exhibits multi-receptor binding to human somatostatin receptor (SSTR) subtypes (SSTR 1-5). Recently, we extended this research utilising the hydroxproline urethane extension of SOM230 for the attachment of the chelators DTPA and DOTA, which enable early diagnosis of SSTR positive tumors and radiotherapy.