What New Dosimetry Data Reveals About 177Lu-Edotreotide for GEP-NET Treatment

Recently published findings from the phase 3 COMPETE trial demonstrated that¹⁷⁷Lu-edotreotide, apeptide receptor radionuclide therapy, provided a greater than nine-month improvement over everolimus in median progression-free survival for patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

New subanalysis research from the COMPETE trial, involving abdominal single-photon emission computed tomography (SPECT), shows intriguing dosimetry data for ¹⁷⁷Lu-edotreotide in this patient population.

For the sub-analysis, recently presented at the American Society for Radiation Oncology (ASTRO) conference, researchers reviewed multiple whole-body planar imaging obtained up to 96 hours post-dose and abdominal SPECT imaging obtained 24 hours after administration of each of the four cycles of treatment with ¹⁷⁷Lu-edotreotide. The study authors assessed dosimetry data for healthy organs in 17 patients and tumor dosimetry in nine patients, according to the sub-analysis.¹

In a recent interview with Diagnostic Imaging, lead study author Amir Iravani, MD, FRACP, noted that the median kidney absorbed dose coefficients (ADC) remained relatively consistent across the four treatment cycles (ranging from 0.44 to 0.47 Gy/GBq) with a 14 percent intra-patient variability. Dr. Iravani also noted the consistency of a favorable tumor-to-kidney ADC across each treatment cycle with ¹⁷⁷Lu-edotreotide.¹

“This is very important because … if we do dosimetry at cycle one, we may not necessarily need to do that comprehensive dosimetry to kind of project what is going to be the cumulative absorbed dose within each patient after receiving all four cycles of treatment. Although all patients may need to have the dosimetry (as the) absorbed dose might be different, within each patient, we could basically project and predict what would be the cumulative dose to the kidney, and I think this was the first and most important finding of this study,” explained Dr. Iravani, an associate professor and vice chair of clinical research and theranostics within the Department of Nuclear Medicine and Theranostics at the David Geffen School of Medicine at the University of California, Los Angeles (UCLA).

Future research with ¹⁷⁷Lu-edotreotide may reveal further insights on facilitating more personalized targeted treatment in patients with GEP-NETs, according to Dr. Iravani.

“The future direction would be personalizing this treatment and modifying and modulating the treatment based on the absorption dose to the normal organs and the tumors in the future with the hope that that approach would even improve upon what has been achieved from this agent in this trial,” posited Dr. Iravani.

Reference

1. Iravani A, Deshayes E, de Mestier L, et al. ¹⁷⁷Lu-edotreotide absorbed dose in patients with gastroenteropancreatic neuroendocrine tumors dosimetry results from COMPETE.Presented at the American Society for Radiation Oncology (ASTRO) Annual Meeting, September 26-September 30, 2026, Boston. Available at: https://www.astro.org/meetings-and-education/micro-sites/2026/annual-meeting .