NANETS2025 18th Annual Multidisciplinary NET Medical Symposium NANETS 2025 Clinical – Nuclear Medicine/Interventional Radiology/Imaging (22 abstracts)
Phase 2 Study of Targeted Alpha Therapy 212Pb-DOTAMTATE in Patients with Advanced Gastroenteropancreatic (GEP)-NETs Previously Treated with PRRT
Jonathan R. Strosberg 1 , Shagufta Naqvi 2 , Allen L. Cohn 3 , Ebrahim S. Delpassand 4 , Volker J. Wagner 5 , Izabela Tworowska 4 , Julien Torgue 5 , Rachel Woloski 5 , Katherine Ruffner 5 , Ashok Krishna 6 , Fatima Menas 7 , Zhe Chen 6 & Mary A. Maluccio 8
1Moffitt Cancer Center and Research Institute, Tampa, FL; 2Excel Diagnostics Nuclear Oncology Center, Houston, TX; 3Rocky Mountain Cancer Centers, Denver, CO; 4RadioMedix Inc., Houston, TX; 5Orano Med LLC, Plano, TX; 6Sanofi, Cambridge, MA; 7Sanofi, Madrid, Spain; 8Louisiana State University, New Orleans, LA
Background: Effective treatment options are limited for patients with unresectable or metastatic Gastroenteropancreatic Neuroendocrine Tumors (GEP-NETs) whose disease progresses after peptide receptor radionuclide therapy (PRRT) with beta-emitting 177Lu-labelled somatostatin analogs (SSA). 212Pb-DOTAMTATE (SAR447873) is a novel SSTR-targeted alpha therapy under clinical evaluation for patients with SSTR+ NETs in a Phase 2 two-cohort trial (ALPHAMEDIX 02 [NCT05153772]). In PRRT-naïve patients (cohort 1), treatment was associated with a 54.3% overall response rate (ORR) and a manageable safety profile. Here we report the first efficacy and safety results in patients previously treated with PRRT (cohort 2).
Methods: This is a Phase 2, open-label, multicenter study evaluating the clinical activity of 212Pb-DOTAMTATE in PRRT-naïve and PRRT-exposed patients with histologically confirmed unresectable or metastatic GEP-NETs, positive SSA imaging and at least 1 site of measurable disease. PRRT-exposed patients had progressive disease after receiving ≤4 doses of 177Lu-SSA and received their last dose ≥6 months prior to Day 1. 212Pb-DOTAMTATE was administered at 67.6 μCi/kg every 8 weeks for up to 4 cycles. Primary endpoints include ORR per RECIST1.1, and safety. Secondary endpoints include progression free survival and overall survival.
Results: Among 26 PRRT-exposed patients, the most common primary tumor sites were pancreas and small intestine (both n = 11, 42.3%). The majority (n = 20; 76.9%) had Grade 1/2 tumors. Eight patients (30.8%) achieved a confirmed partial response (PR); 17 (65.4%), stable disease (with 1 unconfirmed PR pending confirmation); and 1 (3.8%), progressive disease (96.2% disease control rate). Seven of 8 patients with a confirmed PR maintained their response at the time of data cutoff. All patients experienced at least one treatment-emergent adverse event (TEAE), with 9 (34.6%) having at least one Grade ≥3 TEAE. The most common Grade 3 or 4 TEAE was lymphocyte count decrease (15.4%).
Conclusions: In patients with unresectable or metastatic SSTR+ GEP-NETs previously treated with PRRT,212Pb-DOTAMTATE (SAR447873) was associated with a clinically meaningful overall response rate of 30.8%. TEAEs were generally Grade1 or 2 and manageable.
Abstract ID #33429
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Endocrine Abstracts
ISSN 1470-3947 (print) | ISSN 1479-6848 (online)
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