Safety and Efficacy of Radionuclide Therapy with High-Activity In-111 Pentetreotide in Patients with Progressive Neuroendocrine Tumors

The intent of this study was to evaluate the safety and efficacy of high-activity 111In-pentetreotide in pa-tients with neuroendocrine tumors. Thirty-two patients with pentetreotide-avid neuroendocrine tumors re-ceived therapy from August 2005 to November 2006. Fourteen (14) patients received 1 treatment and 18 patients received 2 treatments. Patients were followed an average of 12.73 months (range 1.2–24.5). Sev-enteen (17) patients (53%) had grade I or II hematologic toxicities, and 1 patient had grade III throm-bocytopenia. One patient had grade II liver toxicity, which appeared 4 weeks after therapy and resolved on week 5. No patient had renal toxicity. Of the patients who completed 2 treatment cycles, 2 of 18 pa-tients had partial disease regression, and 16 of 18 patients with previously progressive disseminated neu-roendocrine disease achieved stable disease by imaging criteria. A decrease in serum tumor markers was observed in 14 of 18 patients given 2 therapies. A clinical response was achieved in 84 % of the patients. Upon interim analysis, median survival was approximately 13 months (range 1.2–24.5). These results show that high-activity 111In-pentetreotide therapy is effective in patients with progressive disseminated neuroendocrine tumors. Key words: neuroendocrine tumors, radionuclide therapy, pentetreotid