⁹⁰Y-edotreotide for metastatic carcinoid refractory to octreotide

Purpose: Metastatic carcinoid is an incurable malignancy whose symptoms, such as diarrhea and flushing, can be debilitating and occasionally life-threatening. Although symptom relief is available with octreotide, the disease eventually becomes refractory to octreotide, leaving no proven treatment options. The goal of this study was to evaluate the clinical effect of using ⁹⁰Y-edotreotide to treat symptomatic patients with carcinoid tumors. Patients and Methods: Patients enrolled had metastatic carcinoid, at least one sign/symptom refractory to octreotide, and at least one measurable lesion. Study treatment consisted of three cycles of 4.4 GBq (120 mCi) ⁹⁰Y- edotreotide each, once every 6 weeks. Results: Ninety patients were enrolled in the study. Using Southwest Oncology Group tumor response criteria, 67 (74.4%) of 90 patients (95% CI, 65.4% to 83.4%) were objectively stable or responded. A statistically significant linear trend toward improvement was demonstrated across all 12 symptoms assessed. Median progression-free survival was significantly greater (P = .03) for the 38 patients who had durable diarrhea improvement than the 18 patients who did not (18.2 v 7.9 months, respectively). Adverse events (AEs) were reported in 96.7% (87 of 90) of patients. These AEs consisted primarily of reversible GI events (76 of 90), which could be caused in part by concomitant administration of amino acid solution given to reduce radiation exposure to the kidneys. There was one case each of grade 3 oliguria and grade 4 renal failure, each lasting 6 days. Conclusion: ⁹⁰Y- edotreotide treatment improved symptoms associated with malignant carcinoid among subjects with no treatment alternatives. Treatment was well-tolerated and had an acceptable expected AE profile.