Cumulated Activity Comparison of Cu-64-/Lu-177-Labeled Anti-Epidermal Growth Factor Receptor Antibody in Esophageal Squamous Cell Carcinoma Model

摘要

This work aimed at estimating the kinetic parameters, and hence cumulated activity (A(C)), of a diagnostic/therapeutic convergence radiopharmaceutical, namely Cu-64-/Lu-177-labeled antibody (Cu-64-/Lu-177-cetuximab), that acts as anti-epidermal growth factor receptor. Methods: In mice bearing esophageal squamous cell carcinoma tumors, to estimate uptake (K), release rate constant (k(R)), and hence A(C), a kinetic model analysis was applied to recently published biodistribution data of immuno-PET imaging with Cu-64-cetuximab and of small-animal SPECT/CT imaging with Lu-177-cetuximab, including blood and TE-8 tumor. Results: K, k(R), and A(C) were estimated to be 0.0566/0.0593 g.h(-1).g(-1), 0.0150/0.0030 h(-1), and 2.3 X 10(10)/4.1 X 10(12) disintegrations (per gram of TE-8 tumor), with an injected activity of 3.70/12.95 MBq, for Cu-64-/Lu-177-cetuximab, respectively. Conclusion: A model is available for comparing kinetic parameters and A(C) of the companion diagnostic/therapeutic Cu-64-/Lu-177-cetuximab that may be considered as a step for determining whether one can really use the former to predict dosimetry of the latter.