First clinical evidence that imaging with somatostatin receptor antagonists is feasible

• Published in: Journal of Nuclear Medicine Vol. 52; no. 9; pp. 1412 - 1417
• Main Authors: Wild, Damian, Fani, Melpomeni, Behe, Martin, Brink, Ingo, Rivier, Jean E F, Reubi, Jean Claude, Maecke, Helmut R, Weber, Wolfgang A
• Format: Journal Article
• Language: English
• Published: United States Society of Nuclear Medicine 01-09-2011
• Subjects: Aged; Binding sites; Coordination Complexes - adverse effects; Endocrine Gland Neoplasms - diagnostic imaging; Feasibility Studies; Growth hormones; Humans; Male; Mass spectrometry; Medical imaging; Middle Aged; Molecular Imaging - methods; Neuroendocrine Tumors - diagnostic imaging; Octreotide - analogs & derivatives; Octreotide - pharmacokinetics; Pentetic Acid - analogs & derivatives; Pentetic Acid - pharmacokinetics; Peptides, Cyclic - adverse effects; Prospective Studies; Radiometry; Radionuclide Imaging; Radiopharmaceuticals - pharmacokinetics; Receptors, Somatostatin - antagonists & inhibitors; Thyroid Neoplasms - diagnostic imaging; Tissue Distribution; Tumors; Whole Body Imaging
• ISSN: 0161-5505; 1535-5667; 2159-662X
• DOI: 10.2967/jnumed.111.088922

Preclinical studies have indicated that somatostatin receptor (sst)-expressing tumors demonstrate higher uptake of radiolabeled sst antagonists than of sst agonists. In this study, we evaluated whether imaging with sst antagonists was feasible in patients.
Biodistribution and tumor uptake of the sst antagonist (111)In-DOTA-pNO(2)-Phe-c(DCys-Tyr-DTrp-Lys-Thr-Cys)DTyrNH(2) ((111)In-DOTA-BASS) were studied in 5 patients with metastatic thyroid carcinoma or neuroendocrine tumors. Findings were compared with (111)In-pentetreotid ((111)In-DTPA-octreotide) scan.
No adverse effects of (111)In-DOTA-BASS (20 μg) were observed. (111)In-DOTA-BASS detected 25 of 28 lesions, whereas (111)In-DTPA-octreotide detected only 17 of 28 lesions. In the same patient, (111)In-DOTA-BASS showed higher tumor and lower renal uptake than (111)In-DTPA-octreotide (3.5 ± 2.8 percentage injected activity [%IA] vs. 1.0 ± 0.99%IA and 1.5 ± 0.3 %IA vs. 2.3 ± 0.7 %IA) at 4 h after injection.
Imaging of neuroendocrine tumors with sst antagonists is clinically feasible. The favorable human biodistribution data suggest that sst antagonists could significantly affect peptide receptor-mediated imaging and therapy.