ITM Isotope Technologies Munich SE announced comprehensive dosimetry data from its Phase 3 COMPETE trial, providing detailed radiation absorption measurements for 177Lu-edotreotide (ITM-11) in patients with Grade 1 or Grade 2 somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors (GEP-NETs). The findings, presented at the 38th Annual Congress of the European Association of Nuclear Medicine in Barcelona, demonstrate the radiopharmaceutical's ability to deliver targeted radiation to tumors while sparing healthy tissue.
Dosimetry Analysis Reveals Favorable Therapeutic Window
The dosimetry evaluation encompassed all 207 patients treated with 177Lu-edotreotide in the randomized trial, making it the first large-scale dosimetry analysis in a Phase 3 radiopharmaceutical study for GEP-NETs. Absorbed dose measurements for target tumors and organs were obtained through whole body planar imaging and abdominal single-photon emission computed tomography (SPECT) 3D imaging at cycle 1, with red bone marrow dosimetry performed in a subset of 20 patients using additional blood samples.
The data revealed a significant therapeutic advantage, with mean cumulative absorbed dose extrapolated from cycle 1 showing tumor uptake of 110.0 ± 90.8 Gy compared to substantially lower doses in normal organs. Kidney exposure measured 12.5 ± 4.4 Gy, well below the assumed safety threshold of 23 Gy, while red bone marrow absorbed dose was 0.7 ± 0.4 Gy, significantly under the 2 Gy safety threshold.
Safety Profile Supports Clinical Efficacy
The dosimetry findings align with the trial's safety outcomes, demonstrating reduced toxicity in dose-limiting organs compared to the control arm. Grade ≥1 renal adverse events occurred in 14.7% of patients receiving 177Lu-edotreotide versus 21.2% with everolimus. Blood and lymphatic disorders showed similar rates between treatments (40.1% vs. 41.4%).
"With these data combining extensive dosimetry information from more than 200 patients included in a prospective trial, ITM is laying the groundwork for improved therapeutic decision-making by providing important insights into tumor uptake and treatment variability," said Emmanuel Deshayes, MD, PhD, professor in biophysics and nuclear medicine at Montpellier Cancer Institute, France, who presented the findings.
Recognition and Future Applications
The research received the prestigious EANM Marie Curie Award, recognizing exceptional scientific quality and contribution to nuclear medicine. Dr. Deshayes, the study investigator and nuclear medicine physician, accepted the award during the congress.
The dosimetry data directly informed the design of ITM's ongoing Phase 3 COMPOSE trial evaluating ITM-11 in well-differentiated, aggressive Grade 2 or Grade 3 SSTR-positive GEP-NET tumors, as well as the upcoming Phase 1 pediatric KinLET study in SSTR-positive tumors.
Broader Impact on Radiopharmaceutical Development
ITM recently joined the Foundation for the National Institutes of Health Biomarkers Consortium's Precision Dosimetry Imaging Biomarker Project, contributing its dosimetry data to establish standardized imaging and dosing methods for improved radiopharmaceutical development and patient outcomes.
"As the first company to conduct dosimetry in a large, randomized Phase 3 radiopharmaceutical trial in patients with Grade 1 or 2 GEP-NETs, we are encouraged by these findings, which align with the favorable therapeutic and safety profile of ¹⁷⁷Lu-edotreotide observed in our COMPETE trial," said Dr. Andrew Cavey, chief executive officer of ITM.
The COMPETE trial previously met its primary endpoint in January and March 2025, demonstrating significantly longer median progression-free survival with 177Lu-edotreotide compared to everolimus in the 309-patient randomized study. The comprehensive dosimetry analysis provides mechanistic support for these clinical outcomes and establishes a foundation for personalized radiopharmaceutical therapy approaches.
