C-Terminal Selective Ligation to Access Homogeneous Antibody Conjugates

C 端选择性连接以获得同源抗体缀合物

• 批准号: EP/T016043/1
• 负责人: James Baker
• 金额: $ 56.61万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FT016043%2F1
• 关键词: Terminal; Selective; Ligation; Access; Homogeneous

Antibody-Drug Conjugates (ADCs) represent one of the most exciting classes of new targeted anti-cancer therapeutics, with 4 ADCs achieving clinical approval over the last 8 years. They consist of an antibody, which is a protein macromolecule that specifically binds to an antigen overexpressed on a cancer cell surface, attached to a cytotoxic chemical 'warhead'. They aim to overcome the limitations of existing chemotherapeutics by delivering the cytotoxic drug specifically to the cancer cells, and thus reducing the side-effects associated with damaging healthy tissue. To maximise the chances for ADCs achieving their therapeutic potential, their design and chemical construction must be improved. Critically, current approaches for the attachment of the drug to the antibody have relied on unselective chemistries, which generate highly complex mixtures of conjugates with variable pharmacological profiles. Instead, it is now widely accepted that the attachment method for the next generation of optimised ADCs must be site-selective. In this project we are proposing to pioneer a new approach for the generation of ADCs, which attaches the drugs at specific locations on the antibody by extending the protein chain, generating superior homogeneous conjugates. Our strategy, crucially, will not require genetic engineering of the antibodies to incorporate reactive handles, and is thus applicable directly to native 'off-the-shelf' antibodies. This will maximise the accessibility of homogenous ADCs to researchers across the world and ensure that the production yields are maintained as high as possible, ultimately reducing the cost of these relatively complex biopharmaceuticals. Moreover, it will form ADCs with a controlled loading of 2 drugs, which is timely as many of the new ultra-potent warheads can only be tolerated at such loadings as they are so hydrophobic. We will achieve this goal by targeting the C-terminal cysteines present on the vast majority of clinically validated antibodies. This is a challenging aim as whilst a wide variety of methods have been established for the selective modification of various amino acids on peptides/proteins, there is an absence of a reliable strategy for modification at the C-terminus. As such, the development of a C-terminal modification strategy would also provide a fundamental advance in the broader field of bioconjugation. Our strategy exploits cysteine reactive reagents, which will be designed to transfer from Cys-to-C-terminus via highly favourable 6-membered ring intermediates. The reactions will result in the formation of amide linkages, which are already extremely well characterised and known to be robustly stable in vivo. Overall this C-terminal modification strategy will represent an optimum approach for producing next generation ADCs and facilitate the wider success of these exciting targeted therapies.

抗体 - 药物缀合物（ADC）代表了最令人兴奋的新靶向抗癌治疗类别之一，在过去的8年中，有4个ADC获得了临床认可。它们由抗体组成，该抗体是一种蛋白质大分子，该抗体与在癌细胞表面过表达的抗原特异性结合，附着于细胞毒性化学“弹头”。他们的目的是通过将细胞毒性药物专门提供给癌细胞，从而减少与损害健康组织有关的副作用，从而克服现有化学治疗剂的局限性。为了最大程度地提高ADC获得其治疗潜力的机会，必须改善其设计和化学结构。至关重要的是，当前的药物附着在抗体上的方法取决于非选择性化学物质，从而产生了具有可变的药理特征的偶联物的高度复杂混合物。取而代之的是，现在广泛接受的是，下一代优化ADC的附件必须是现场选择性的。 在这个项目中，我们建议通过扩展蛋白质链，从而在抗体上的特定位置附加在特定位置的ADC生成新方法，从而产生优质的均匀共轭物。至关重要的是，我们的策略不需要抗体的基因工程来融合反应性手柄，因此直接适用于天然的“现成”抗体。这将最大化同质ADC对世界各地的研究人员的可及性，并确保生产产量尽可能高，最终降低了这些相对复杂的生物制药的成本。此外，它将形成2种药物的受控负载的ADC，这是及时的，因为许多新的超电力弹头只能在这样的载荷下可耐受，因为它们是如此疏水。 我们将通过针对绝大多数临床验证抗体的C末端半胱氨酸来实现这一目标。这是一个具有挑战性的目标，尽管已经建立了各种方法来选择性修饰肽/蛋白质上各种氨基酸，但缺乏在C末端进行修改的可靠策略。因此，C末端修改策略的制定还将在更广泛的生物缀合领域提供基本进步。我们的策略利用了半胱氨酸反应性试剂，该试剂将通过高度有利的6元环中间体从CYS到C末端转移。这些反应将导致形成酰胺链接，酰胺链接已经非常良好，并且已知在体内稳定。总体而言，这种C末端修改策略将代表生产下一代ADC的最佳方法，并促进这些令人兴奋的目标疗法的更广泛成功。