Overview of Development and Formulation of 177Lu-DOTA-TATE for PRRT

Peptide receptor radionuclide therapy (PRRT) using radiolabeled somatostatin analogs has become an established procedure for the treatment of patients suffering from inoperable neuroendocrine cancers over-expressing somatostatin receptors. Success of PRRT depends on the availability of the radiolabeled peptide with adequately high specific activity, so that required therapeutic efficacy can be achieved without saturating the limited number of receptors available on the target lesions. Specific activity of the radionuclide and the radiolabeled somatostatin analog are therefore important parameters. Although these analogs have been investigated and improved, and successfully applied for PRRT for more than 15 years, there are still many possibilities for further improvements that fully exploit PRRT with Lu-177-DOTA-TATE. The summarized data presented herein on increased knowledge of the components of Lu-177-DOTA-TATE (especially the purity of Lu-177 and specific activity of Lu-177) and the reaction kinetics during labeling Lu-177-DOTA-TATE clearly show that the peptide dose and dose in GBq can be varied. Here we present an overview of the development, formulation and optimisation of Lu-177-DOTA-TATE, mainly addressing radiochemical parameters.