TY - JOUR T1 - <sup>131</sup>I-GD2-ch14.18 Scintigraphy to Evaluate Option for Radioimmunotherapy in Patients with Advanced Tumors JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 205 LP - 211 DO - 10.2967/jnumed.120.261854 VL - 63 IS - 2 AU - Ying Zhang AU - Juergen Kupferschlaeger AU - Peter Lang AU - Gerald Reischl AU - Rupert J. Handgretinger AU - Christian la Fougère AU - Helmut Dittmann Y1 - 2022/02/01 UR - http://jnm.snmjournals.org/content/63/2/205.abstract N2 - The tumor-selective ganglioside antigene GD2 is frequently expressed on neuroblastomas and to a lesser extent on sarcomas and neuroendocrine tumors. The aim of our study was to evaluate the tumor targeting and biodistribution of 131I-labeled chimeric GD2-antibody clone 14/18 (131I-GD2-ch14.18) in patients with late-stage disease in order to identify eligibility for radioimmunotherapy. Methods: Twenty patients (neuroblastoma, n = 9; sarcoma, n = 9; pheochromocytoma, n = 1; and neuroendocrine tumor, n = 1) were involved in this study. A 21- to 131-MBq dose (1–2 MBq/kg) of 131I-GD2-ch14.18 (0.5–1.0 mg) was injected intravenously. Planar scintigraphy was performed within 1 h from injection (day 0) and on days 1, 2, 3, and 6 or 7 to analyze tumor uptake and tracer biodistribution. Serial blood samples were collected in 4 individuals. Absorbed dose to tumor lesions and organs was calculated using OLINDA software. Results: The tumor-targeting rate on a per-patient base was 65% (13/20), with 6 of 9 neuroblastomas showing uptake of 131I-GD2-ch14.18. Tumor lesions showed maximum uptake at 20–64 h after injection (effective half-life in tumors, 33–192 h). The tumor-absorbed dose varied between 0.52 and 30.2 mGy/MBq (median, 9.08 mGy/MBq; n = 13). Visual analysis showed prominent blood-pool activity up to day 2 or 3 after injection. No pronounced uptake was observed in the bone marrow compartment or in the kidneys. Bone marrow dose was calculated at 0.09–0.18 mGy/MBq (median, 0.12 mGy/MBq), whereas blood dose was 1.1–4.7 mGy/MBq. Two patients (1 neuroblastoma and 1 pheochromocytoma) with particularly high tumor uptake underwent radioimmunotherapy using 2.3 and 2.9 GBq of 131I-GD2-ch14.18, both achieving stable disease. Overall survival was 17 and 6 mo, respectively. Conclusion: 131I-GD2-ch14.18 is cleared slowly from blood, not resulting in good tumor-to-background contrast until 2 d after application. With acceptable red marrow and organ dose, radioimmunotherapy is an option for patients with high tumor uptake. However, because of the variable GD2 expression, the decision should depend on pretherapeutic dosimetry. ER -