Pharmacokinetics and biodistribution of 177Lu-labeled multivalent single-chain Fv construct of the pancarcinoma monoclonal antibody CC49
Pharmacokinetics and biodistribution of 177Lu-labeled multivalent single-chain Fv construct of the pancarcinoma monoclonal antibody CC49
复制标题
DOI：
10.1007/s00259-004-1664-0
复制
发表时间：
2005-03-01
影响因子：
9.1
通讯作者：
Batra, SK
中科院分区：
文献类型：
--
作者：
Chauhan, SC;Jain, M;Batra, SK
目的：镥-177（Lu-177）是放射免疫成像（RII）和放射免疫治疗（RIT）的感兴趣的放射性核素，因为它的半衰期短（161小时），能够发射β和γ辐射。单链抗体（scFv）构建体由于其药代动力学优势而在癌症诊断和治疗中显示出进步，并且似乎是肿瘤学中有趣的工具。本研究的目的是评价（177）上标stopLu标记的CC 49单抗四价单链抗体和完整的CC 49 IgG在体内的药代动力学和生物分布特征。方法：在不影响多价单链抗体完整性和免疫反应性的前提下，优化多价单链抗体与Lu-177的偶联和标记条件。为此，MAb CC 49的多价scFv构建体{二聚体，sc（Fv）（2）;四聚体，[sc（Fv）（2）]（2）}在巴斯德毕赤酵母中表达为分泌蛋白。将纯化的scFv构建体和IgG形式的CC 49与双功能螯合剂ITCB-DTPA缀合，并用Lu-177标记。在携带LS-174 T异种移植物的无胸腺小鼠中研究了Lu-177标记的CC 49 MAb和完整CC 49 IgG的四价[sc（Fv）（2）]（2）构建体的比较生物分布、血液清除和肿瘤靶向特征。结果如下：使用ITCB-DTPA螯合剂实现约90%的Lu-177掺入，并且标记的免疫缀合物保持完整性和免疫反应性。血液清除研究表明Lu-177标记的[sc（Fv）（2）]（2）和CC 49 IgG的α半衰期（t（1/2 α））分别为4.40和9.50 min，β半衰期（t（1/2 β））分别为375和2，193 min。在不存在L-赖氨酸的情况下，在给药后8小时，对于Lu-177标记的[sc（Fv）（2）]（2）和CC 49的IgG，LS-174 T肿瘤的注射剂量累积/克（%ID/g）百分比分别为6.4 +/- 1.3和8.9 +/- 0.6。在L-赖氨酸存在下，相应的值为8.0 +/-0.6和8.4 +/-1.2。在L-赖氨酸存在下，[sc（Fv）（2）]（2）的肾积累显著降低（p < 0.005）。结论：本研究的结果表明，ITCB-DTPA缀合和Lu-177标记scFv是可行的，而不影响抗体特性。Lu-177标记的[sc（Fv）（2）]（2）在8 h时与其IgG形式相比显示出更快的清除率和等效的肿瘤摄取，在存在L-赖氨酸的情况下肾摄取显著降低。因此，Lu-177标记的[sc（Fv）（2）]（2）可能是一种潜在的治疗癌症的放射性药物。
Purpose: Lutetium-177 (Lu-177) is a radionuclide of interest for radioimmunoimaging (RII) and radioimmunotherapy (RIT) on account of its short half-life (161 h) and the ability to emit both beta and gamma radiation. Single-chain Fv (scFv) constructs have shown advancement in cancer diagnosis and therapy due to the pharmacokinetics advantage and seem to be intriguing tools in oncology. The objective of this study was to evaluate the pharmacokinetics and biodistribution characteristics of the (177)supercript stopLu-labeled tetravalent scFv of CC49 MAb and intact CC49 IgG in vivo. Methods: Conjugation and labeling conditions of multivalent scFv with Lu-177 were optimized without affecting integrity and immunoreactivity. For this purpose, multivalent scFv constructs {dimer, sc(Fv)(2); tetramer, [sc(Fv)(2)](2)} of the MAb CC49 were expressed as secretory proteins in Pichia pastoris. The purified scFv constructs and IgG form of CC49 were conjugated with a bifunctional chelating agent, ITCB-DTPA, and labeled with Lu-177. The comparative biodistribution, blood clearance, and tumor-targeting characteristics of Lu-177-labeled tetravalent [sc(Fv)(2)](2) construct of CC49 MAb and intact CC49 IgG were investigated in the athymic mice bearing LS-174T xenografts. Results: Approximately, 90% of Lu-177 incorporation was achieved using ITCB-DTPA chelator, and the labeled immunoconjugates maintained integrity and immunoreactivity. Blood clearance studies demonstrated an alpha half-life (t(1/2 alpha)) of Lu-177-labeled [sc(Fv)(2)](2) and IgG of CC49 at 4.40 and 9.50 min and a beta half-life (t(1/2)beta) at 375 and 2,193 min, respectively. At 8 h post administration, the percent of the injected dose accumulated/gram (%ID/g) of the LS-174T tumor was 6.4 +/- 1.3 and 8.9 +/- 0.6 for Lu-177-labeled [sc(Fv)(2)](2) and IgG of CC49, respectively, in the absence of L-lysine. The corresponding values were 8.0 +/- 0.6 and 8.4 +/- 1.2 in the presence of L-lysine. Renal accumulation of [sc(Fv)(2)](2) was significantly (p < 0.005) reduced in the presence of L-lysine. Conclusion: The results of this study demonstrate that the ITCB-DTPA conjugation and Lu-177-labeling of scFvs are feasible without influencing the antibody characteristics. Lu-177-labeled [sc(Fv)(2)](2) showed faster clearance and equivalent tumor uptake at 8 h compared with its IgG form, with a markedly reduced renal uptake in the presence of L-lysine. Therefore, Lu-177-labeled [sc(Fv)(2)](2) may be a potential radiopharmaceutical for the treatment of cancer.