Recurrent Metastatic Esthesioneuroblastoma: First-in-human α/β PRRT With Actinium-225/Lutetium-177-DOTA-LM3 SSTR Antagonist Achieving Partial Response After Failure of Lutetium-177-DOTATOC PRRT.

A 45-year-old woman with heavily pretreated, recurrent metastatic esthesioneuroblastoma and progressive symptomatic disease underwent first-in-human peptide receptor radionuclide therapy (PRRT) using the somatostatin receptor (SSTR) antagonist DOTA-LM3 labeled with actinium-225 and lutetium-177 (TANDEM). Two PRRT cycles were administered without acute adverse events. Post-cycle-1 SPET/CT demonstrated intense uptake in local, lymph nodal, osseous, cerebral, mediastinal, and hilar lesions. After cycle-2, molecular imaging documented partial remission, with reduced radiopharmaceutical uptake (partial response according to THERCIST) in most lesions, accompanied by significant clinical improvement with pain reduction. This case demonstrates the feasibility of combined alpha- and beta-emitting SSTR-antagonist PRRT in advanced esthesioneuroblastoma.