Radiopharmaceutical Department, Nuclear Physics Institute of the Academy of Sciences, Husinec-Rez, Czech Republic.
Cancer Biother Radiopharm. 2011 Jun;26(3):287-97. doi: 10.1089/cbr.2010.0916. Epub 2011 Jun 28.
The humanized monoclonal antibody Nimotuzumab (h-R3) has demonstrated an exceptional and better clinical profile than other monoclonal antibodies for immunotherapy of epidermal growth factor receptor-overexpressing tumors. This work deals with the preparation and radiolabeling optimization of (177)Lu-Nimotuzumab and their preclinical evaluation.
Nimotuzumab was conjugated with S-2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane tetraacetic acid (p-SCN-Bn-DOTA), testing different molar ratios. The immunoconjugates were characterized. The radiolabeling with (177)Lu was optimized. Radioimmunoconjugates stability was tested in 2-[bis[2-[bis(carboxymethyl)amino]ethyl]amino]acetic acid (DTPA) excess and human serum. In vitro studies were performed in tumor model cell lines. Receptor-specific binding was tested by competitive inhibition. (177)Lu-Nimotuzumab in vivo studies were conducted in healthy and xenograft animals.
Nimotuzumab conjugates were obtained with high purity. Radiolabeling yield and specific activities ranged from 63.6% to 94.5% and from 748 to 1142 MBq/mg, respectively. The stability in DTPA excess and human serum was 95.9% and 93.2% after 10 days, respectively. The radioimmunoconjugate showed specific receptor binding in tumor cell lines. Biodistribution in healthy animals showed the typical behavior of the immunoconjugates based on monoclonal antibodies. The study in xenografts mice demonstrated uptake of (177)Lu-Nimotuzumab in the tumor and reticuloendothelial organs.
(177)Lu-Nimotuzumab was obtained with high purity and specific activities under optimal conditions without significant loss in immunoreactivity and might be a potential radioimmunoconjugate for radioimmunotherapy of tumors with epidermal growth factor receptor overexpression.
人源化单克隆抗体尼妥珠单抗（h-R3）在免疫治疗表皮生长因子受体过表达肿瘤的单克隆抗体中表现出独特且更好的临床特征。本工作涉及（177）Lu-尼妥珠单抗的制备和放射性标记优化及其临床前评价。
尼妥珠单抗与 S-2-（4-异硫氰酸苯甲基）-1,4,7,10-四氮杂环十二烷四乙酸（p-SCN-Bn-DOTA）偶联，测试不同的摩尔比。对免疫偶联物进行了表征。优化了（177）Lu 的放射性标记。在 2-[双[2-[双（羧甲基）氨基]乙基]氨基]乙酸（DTPA）过量和人血清中测试了放射性免疫偶联物的稳定性。在肿瘤模型细胞系中进行了体外研究。通过竞争性抑制试验测试了受体特异性结合。在健康和异种移植动物中进行了（177）Lu-尼妥珠单抗的体内研究。
尼妥珠单抗偶联物获得了高纯度。放射性标记产率和比活度分别为 63.6%至 94.5%和 748 至 1142MBq/mg。在 10 天后，DTPA 过量和人血清中的稳定性分别为 95.9%和 93.2%。放射性免疫偶联物在肿瘤细胞系中显示出特异性受体结合。在健康动物中的生物分布显示了基于单克隆抗体的免疫偶联物的典型行为。在异种移植小鼠的研究中，在肿瘤和网状内皮器官中检测到（177）Lu-尼妥珠单抗的摄取。
在没有明显损失免疫原性的情况下，（177）Lu-尼妥珠单抗在最佳条件下获得了高纯度和比活度，可能是一种用于表皮生长因子受体过表达肿瘤放射免疫治疗的潜在放射性免疫偶联物。
