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Updated: Apr 27, 2026

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Comparison of somatostatin receptor agonist and antagonist for peptide receptor radionuclide therapy: a pilot study

Damian Wild1, Melpomeni Fani2, Richard Fischer3

  • 1Department of Nuclear Medicine, University Hospital Freiburg, Freiburg, Germany Division of Nuclear Medicine, University of Basel Hospital, Basel, Switzerland damian.wild@usb.ch.

Journal of Nuclear Medicine : Official Publication, Society of Nuclear Medicine
|June 26, 2014
PubMed
Abstract

Insights

Treatment with lutetium-177-labeled somatostatin receptor antagonists is feasible for advanced neuroendocrine tumors. This approach demonstrated higher tumor uptake and improved patient outcomes compared to agonists.

Area of Science:

  • Nuclear Medicine
  • Oncology
  • Radiopharmaceutical Therapy

Background:

  • Preclinical and clinical studies suggest somatostatin receptor (sst)-expressing tumors have greater uptake of radiolabeled sst antagonists than agonists.
  • Neuroendocrine tumors (NETs) often express somatostatin receptors, making them potential targets for targeted radionuclide therapy.

Purpose of the Study:

  • To evaluate the clinical feasibility of treating advanced neuroendocrine tumors using lutetium-177 ((177)Lu)-labeled somatostatin receptor antagonists.
  • To compare the dosimetry and therapeutic efficacy of (177)Lu-labeled sst antagonists versus sst agonists in NET patients.

Main Methods:

  • Four patients with advanced neuroendocrine tumors received approximately 1 GBq of (177)Lu-DOTA-JR11 (sst antagonist) and (177)Lu-DOTATATE (sst agonist).
  • Three-dimensional voxel dosimetry analysis using SPECT/CT was performed to assess radiation dose distribution.
  • Treatment with (177)Lu-DOTA-JR11 was contingent on achieving a higher tumor-to-organ dose ratio compared to (177)Lu-DOTATATE.

Main Results:

  • (177)Lu-DOTA-JR11 demonstrated a 1.7-10.6 times higher tumor absorbed dose compared to (177)Lu-DOTATATE.
  • The tumor-to-kidney and tumor-to-bone marrow dose ratios were 1.1-7.2 times higher with (177)Lu-DOTA-JR11.
  • All four patients treated with (177)Lu-DOTA-JR11 achieved partial remission (2 patients), stable disease (1 patient), or mixed response (1 patient), with reversible minor adverse effects.

Conclusions:

  • Treatment of neuroendocrine tumors with radiolabeled somatostatin receptor antagonists is clinically feasible.
  • This therapeutic strategy may significantly advance peptide receptor radionuclide therapy for NETs.
  • The enhanced tumor targeting and dose delivery of sst antagonists offer a promising alternative in NET management.
Keywords:
antagonistsneuroendocrine tumorssomatostatin receptor targeting

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