Conner Kip P, Rock Brooke M, Kwon Gayle K, Balthasar Joseph P, Abuqayyas Lubna, Wienkers Larry C, Rock Dan A
Biochemistry and Biophysics Group in Pharmacokinetics and Drug Metabolism, Amgen Inc., Seattle, Washington (K.P.C., B.M.R., G.K.K., L.C.W., D.A.R.); Department of Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, New York (J.P.B.); and Quantitative Pharmacology Group in Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (L.A.).
Biochemistry and Biophysics Group in Pharmacokinetics and Drug Metabolism, Amgen Inc., Seattle, Washington (K.P.C., B.M.R., G.K.K., L.C.W., D.A.R.); Department of Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, New York (J.P.B.); and Quantitative Pharmacology Group in Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (L.A.)
Drug Metab Dispos. 2014 Nov;42(11):1906-13. doi: 10.1124/dmd.114.060319. Epub 2014 Sep 10.
The pharmacokinetic (PK) behavior of monoclonal antibodies (mAbs) is influenced by target-mediated drug disposition, off-target effects, antidrug antibody-mediated clearance, and interaction with fragment-crystallizable domain (Fc) receptors such as neonatal Fc receptor. All of these interactions hold the potential to impact mAb biodistribution. Near infrared (NIR) fluorescent probes offer an approach complementary to radionuclides to characterize drug disposition. Notably, the use of FDA-approved IRDye800 (IR800; LI-COR, Lincoln, NE) as a protein-labeling agent in preclinical work holds the potential for quantitative tissue analysis. Here, we tested the utility of the IR800 dye as a quantitative mAb tracer during pharmacokinetic analysis in both plasma and tissues using a model mouse monoclonal IgG1 (8C2) labeled with ≤1.5 molecules of IR800. The plasma PK parameters derived from a mixture of IR800-8C2 and 8C2 dosed intravenously to C57BL/6 mice at 8 mg/kg exhibited a large discrepancy in exposure depending on the method of quantitation [CLplasma = 8.4 ml/d per kilogram (NIR fluorescence detection) versus 2.5 ml/d per kilogram (enzyme-linked immunosorbent assay)]. The disagreement between measurements suggests that the PK of 8C2 is altered by addition of the IR800 dye. Additionally, direct fluorescence analysis of homogenized tissues revealed several large differences in IR800-8C2 tissue uptake when compared with a previously published study using [(125)I]8C2, most notably an over 4-fold increase in liver concentration. Finally, the utility of IR800 in combination with whole body imaging was examined by comparison of IR800-8C2 levels observed in animal sagittal cross-sections to those measured in homogenized tissues. Our results represent the first PK analysis in both mouse plasma and tissues of an IR800-mAb conjugate and suggest that mAb disposition is significantly altered by IR800 conjugation to 8C2.
单克隆抗体（mAb）的药代动力学（PK）行为受靶点介导的药物处置、脱靶效应、抗药物抗体介导的清除以及与诸如新生儿Fc受体等可结晶片段（Fc）受体的相互作用影响。所有这些相互作用都有可能影响mAb的生物分布。近红外（NIR）荧光探针提供了一种与放射性核素互补的方法来表征药物处置。值得注意的是，在临床前研究中使用美国食品药品监督管理局（FDA）批准的IRDye800（IR800；LI-COR，林肯，内布拉斯加州）作为蛋白质标记剂具有进行定量组织分析的潜力。在此，我们使用用≤1.5个IR800分子标记的模型小鼠单克隆IgG1（8C2），在血浆和组织的药代动力学分析过程中测试了IR800染料作为定量mAb示踪剂的效用。静脉注射8 mg/kg的IR800-8C2和8C2混合物给C57BL/6小鼠后，根据定量方法的不同，从血浆中得出的PK参数在暴露量上表现出很大差异[血浆清除率（CLplasma）=每千克8.4 ml/天（NIR荧光检测）对每千克2.5 ml/天（酶联免疫吸附测定）]。测量结果之间的差异表明，添加IR800染料会改变8C2的PK。此外，与先前发表的使用[（125）I]8C2的研究相比，对匀浆组织的直接荧光分析显示IR800-8C2在组织摄取方面存在几个大的差异，最明显的是肝脏浓度增加了4倍以上。最后，通过比较在动物矢状横截面中观察到的IR800-8C2水平与在匀浆组织中测量的水平，研究了IR800与全身成像结合的效用。我们的结果代表了对IR800-mAb缀合物在小鼠血浆和组织中的首次PK分析，并表明IR800与8C2缀合会显著改变mAb的处置。
