Schneider Eric L, Hearn Brian R, Pfaff Samuel J, Fontaine Shaun D, Reid Ralph, Ashley Gary W, Grabulovski Stefanie, Strassberger Verena, Vogt Lorenz, Jung Thomas, Santi Daniel V
ProLynx , 455 Mission Bay Blvd. South, Suite 145, San Francisco, California 94158, United States.
Delenex Therapeutics AG , Wagistrasse 27, CH-8952 Schlieren, Germany.
Bioconjug Chem. 2016 Oct 19;27(10):2534-2539. doi: 10.1021/acs.bioconjchem.6b00469. Epub 2016 Oct 7.
The utility of antigen-binding antibody fragments is often limited by their short half-lives. Half-life extension of such fragments is usually accomplished by attachment or binding to high-molecular-weight carriers that reduce the renal elimination rate. However, the higher hydrodynamic radius results in greater confinement in the vascular compartment and, thus, lower tissue distribution. We have developed a chemically controlled drug delivery system in which the drug is covalently attached to hydrogel microspheres by a self-cleaving β-eliminative linker; upon subcutaneous injection, the t of the released drug acquires the t of linker cleavage. In the present work, we compared the pharmacokinetics of an anti-TNFα scFv, the same scFv attached to 40 kDa PEG by a stable linker, and the scFv attached to hydrogel microspheres by a self-cleaving linker. We also developed a general approach for the selective attachment of β-eliminative linkers to the N-termini of proteins. In rats, the scFv had a t of 4 h and a high volume of distribution at steady state (V), suggesting extensive tissue distribution. The PEG-scFv conjugate had an increased t of about 2 days but showed a reduced V that was similar to the plasma volume. In contrast, the tissue-penetrable scFv released from the hydrogel system had a t of about 2 weeks. Thus, the cleavable microsphere-scFv conjugate releases its protein cargo with a prolonged half-life comparable to that of most full-length mAbs and in a form that has the high tissue distribution characteristic of smaller mAb fragments. Other antigen-binding antibody fragments should be amenable to the half-life extension approach described here.
抗原结合抗体片段的效用常常受到其短半衰期的限制。此类片段半衰期的延长通常是通过附着或结合到高分子量载体上实现的，这些载体可降低肾脏清除率。然而，较大的流体动力学半径导致在血管腔室中的限制更大，因此组织分布较低。我们开发了一种化学控制的药物递送系统，其中药物通过自裂解β消除连接子共价连接到水凝胶微球上；皮下注射后，释放药物的半衰期获得连接子裂解的半衰期。在本研究中，我们比较了抗TNFα单链抗体片段（scFv）、通过稳定连接子连接到40 kDa聚乙二醇（PEG）的相同scFv以及通过自裂解连接子连接到水凝胶微球的scFv的药代动力学。我们还开发了一种将β消除连接子选择性连接到蛋白质N端的通用方法。在大鼠中，scFv的半衰期为4小时，稳态时分布容积较大（V），表明组织分布广泛。PEG-scFv缀合物的半衰期增加到约2天，但V降低，类似于血浆容积。相比之下，从水凝胶系统释放的可穿透组织的scFv的半衰期约为2周。因此，可裂解的微球-scFv缀合物以延长的半衰期释放其蛋白质货物，该半衰期与大多数全长单克隆抗体相当，并且以具有较小单克隆抗体片段高组织分布特征的形式存在。其他抗原结合抗体片段应该适用于此处描述的半衰期延长方法。
