Final results of a phase 2A study for the treatment of metastatic neuroendocrine tumors with a fixed activity of (90) Y-DOTA-D-Phe1-Tyr3 octreotide.

BACKGROUND: The objective of this study was to assess the efficacy of (90)Y-DOTA-D-Phe1-Tyr3 octreotide ((90)Y-DOTATOC) therapy with a fixed activity of 2.56 GigaBequerels bimonthly in patients with advanced stage, well differentiated neuroendocrine carcinomas. METHODS: In total, 38 patients were enrolled in this phase 2A protocol. All patients had gastroenteropancreatic neuroendocrine tumors in sharp clinical and radiologic progression despite previous surgery, chemotherapy, and biotherapy. Their survival rate after therapy with (90)Y-DOTATOC was compared with a chronologic control group of patients who had received biotherapy and chemotherapy and with results from a previous similar study. The progression-free survival rate after peptide receptor radionuclide therapy with (90)Y-DOTATOC was determined for all patients until they had documented disease progression according to Response Criteria in Solid Tumors, tumor-related death, or censoring. RESULTS: Seventeen patients (43.6%) had a partial response, 10 patients (25.6%) had stable disease, and 11 patients (28.2%) had progressive disease. A statistically significant difference was observed (P < .001) between the response to (90)Y-DOTATOC treatment and the response to biotherapy with somatostatin analogs and chemotherapy and also between the current results and the results from a previous similar study (P < .05). At the time of the current evaluation with ongoing follow-up for 30 patients, the median progression-free survival was 22.3 months. CONCLUSIONS: The results from this phase 2 study indicated that the treatment of metastatic neuroendocrine tumors with fixed (90)Y-DOTATOC activity is useful and safe.