ADC药物的抗体组成及其作用靶点研究进展*

抗体药物偶联物(antibody-drug conjugates,ADC)是一类由单克隆抗体和小分子细胞毒性药物通过连接子偶联而成的新型生物治疗药物。与传统的细胞毒药物相比,ADC具有靶向性强、毒副作用小等优势,在临床上展现较好的治疗潜力。其中,抗体部分通过与肿瘤细胞表面的靶向抗原结合,精准地将小分子细胞毒性药物递送至肿瘤部位,从而实现肿瘤特异性杀伤效果,是影响ADC疗效的核心要素之一。对近年来ADC药物中抗体的组成及其作用靶点的研究进展进行了综述。     

抗体偶联药物国内研发现状及企业布局分析

抗体偶联药物(antibody-drug conjugates,ADC)由单克隆抗体和小分子细胞毒药物通过连接子偶联而成,因在血液瘤、实体瘤等临床治疗中被证明是一种极有前景的技术手段,已经成为国内外抗体药物研发的新热门方向。系统阐述了ADC药物开发及工业化生产中的核心五要素,对国内ADC的研发管线进行了梳理,并对参与ADC研发的核心企业的技术布局情况进行了分析,以期为相关企业的ADC研发方向选择及地区产业决策提供参考。     

Her2抗体与MMAE偶联物的制备及生物活性研究

目的:制备Her2抗体与海兔毒素MMAE的偶联物,检测该抗体-药物偶联药物(ADC)对于乳腺癌细胞的抑制作用。方法:将Her2抗体通过一个可降解的linker与小分子毒素(MMAE)连接起来,形成抗体药物偶联物(ADC)。通过细胞学试验检测Her2抗体-MMAE偶联物对于肿瘤细胞抑制、细胞凋亡和细胞周期的作用。结果:通过优化偶联条件,ADC偶联率达80%以上。肿瘤细胞生长抑制的实验显示ADC药物的IC50比单克隆抗体的IC50明显降低,作用效果更加明显。细胞凋亡和细胞周期实验结果表明,ADC药物72h诱导细胞凋亡率高达40%,单一抗体药物则仅为20%。结论:该ADC药物具有很好的抑制乳腺癌细胞的作用。     

抗体偶联药物的研究进展与质量控制

抗体偶联药物（antibody-drug conjugates,ADC）因其良好的靶向性及抗癌活性目前已成为抗肿瘤抗体药物研发的新热点和重要趋势,受到越来越多的关注。ADC药物由单克隆抗体、高效应的细胞毒性物质以及连接臂三部分组成,它将抗体的靶向性与细胞毒性药物的抗肿瘤作用相结合,可以降低细胞毒性抗肿瘤药物的不良反应,提高肿瘤治疗的选择性,还能更好地应对靶向单抗的耐药性问题。与传统单抗药物相比,因其结构复杂,ADC药物质量属性分析方法的建立具有更大的难度和特殊性。对抗体偶联药物的研发现状、质量属性分析方法和挑战以及质量控制要点进行了简要介绍,为ADC药物的研究和质量控制提供参考。     

抗体与小分子药物一体化的完美“联姻”——解析抗体-药物偶联物之定点偶联

基于单抗的靶向疗法已成为各种癌症的重要治疗手段,抗体与小分子药物一体化的联姻——抗体—药物偶联物（antibody-drug conjugates,ADC）新药获得了突破性进展。传统ADC是将药物与抗体的赖氨酸残基或链间二硫键还原而产生的半胱氨酸残基相偶联 而形成,其稳定性差,易发生聚集,且其中药物易脱落而产生非治疗性毒副作用。而应用近年发展起来的定点偶联技术所获ADC,除均 一性好外,还保留了母体单抗的药动学性质,毒副作用也远低于具有相同偶联比的传统ADC,极有可能发展成为新一代重磅药物。综述 4种ADC定点偶联方法。     

抗体药物的发展与应用

早期抗体药物是鼠源单克隆抗体,存在免疫原性强、半衰期短等问题。历经数十年的发展,抗体药物从最初的鼠源单抗,逐步发展为人鼠嵌合抗体、人源化抗体及全人源化抗体。通过片段重组、位点修饰、药物偶联等方法,科研人员研发了包括抗体融合蛋白、抗体偶联药物、双特异性抗体、小分子抗体片段等形式多样的抗体药物。抗体药物在恶性肿瘤、自身免疫病、感染性疾病的治疗上发挥重要作用。通过对抗体药物人源化历程,不同类型的抗体结构和特点,以及抗体药物在新型冠状病毒肺炎治疗中的应用进行综述,并对抗体药物的发展前景进行展望,以期为我国抗体药物的研发提供参考。     

抗肿瘤抗体-药物偶联物的临床研究进展

个体化靶向治疗已成为肿瘤临床治疗的新趋势.抗肿瘤靶向药物与传统的细胞毒性化疗药物相比具有特异性高、选择性强和非细胞毒性等优点,近年来发展迅速.抗体-药物偶联物(ADCs)属于抗肿瘤靶向药物,由抗体、“弹头”药物(细胞毒性药物)通过链分子连接而成.ADCs将抗体的靶向性与细胞毒性药物的抗肿瘤作用相结合,可以降低细胞毒性抗肿瘤药物的不良反应,提高肿瘤治疗的选择性,还能更好地应对靶向单抗的耐药性问题.目前,FDA已批准2种ADC药物上市,即Mylotarg和Adcetris,有多种ADCs处于Ⅰ～Ⅲ期临床试验阶段,取得了显著的临床效果.本文概述了以美登素,卡奇霉素、Auristantin等三种细胞毒性药物为“弹头”药物的ADCs药物的临床研究状况及临床试验结果,为ADCs的研究和应用提供参考.     

基于单克隆抗体的肿瘤免疫疗法研究进展

一百多年前,"魔术子弹"学说首次提出了具有靶向特异性的抗体可以用来治疗疾病。此后,随着单克隆抗体制备技术的成熟,以及癌症血清疗法的发展,靶向肿瘤抗原的治疗性抗体开始进入临床,至今已有20余种抗体药物用于癌症的治疗。近两年,以免疫检查点蛋白拮抗剂、双特异性抗体、抗体药物偶联药物等为代表的新一代抗体药物,不断在治疗恶性肿瘤上取得突破性进展。本文回顾了抗肿瘤抗体的发展历程,总结了新一代抗体药物的作用机制与构建策略,以及主要临床副作用。并对基于抗体的肿瘤免疫疗法未来发展趋势进行了展望。     

基于亲和探针的药物靶点鉴定技术研究进展

药物靶点的鉴定和相关研究在药学研究领域具有重要的理论指导意义和实用价值。利用亲和探针偶联靶分子的方法是目前发现药 物靶点的主要手段之一。该方法可从分子水平发现药物的作用靶点,从而对药物的分子作用机制提供细胞水平的直接证据。从 DNA 和小 分子药物探针的构筑和应用入手,对近些年鉴定 DNA 损伤识别蛋白的研究进展进行了较为详尽的讨论,并简要介绍目前探索小分子药物 作用靶点的主流技术。作为亲和偶联鉴定药物作用靶点方法的重要组成部分,亲和探针设计的合理性关系到方法本身的可操作性以及鉴 定结果的可靠性。从多个角度对 DNA 探针和小分子药物探针的设计经验进行了较为系统的总结,例如经典的亲和纯化分离方法,以及更 为高效的光激发共价偶联技术等。这些方法和思路为探索 DNA 损伤相关蛋白质的功能以及小分子药物的细胞作用机制提供了丰富的研究 工具,有助于从分子水平理解药物的作用机制。     

聚乙二醇修饰小分子药物的研究进展

以高聚物作为载体,携带各种活性化合物组成药物释放系统,在现代医疗中发挥了巨大的作用。高分子偶联物不仅可以改变药物的药动学特征,还可以通过偶联特异性的物质使药物具有主动靶向性。目前研究最广泛的高分子载体是聚乙二醇。聚乙二醇通过与肽链、抗体、酶等活性化合物偶联,可以提高药物溶解度,延长循环半衰期,减少非特异性摄取,增加靶向性。已有很多聚乙二醇修饰的药物上市,也有很多尚处于临床研究阶段。大部分聚乙二醇化药物的临床研究表明,聚乙二醇修饰的药物确实可以提高药效、降低毒副作用。但关于聚乙二醇修饰小分子药物的设计依然需要进一步研究和完善。我们主要讨论聚乙二醇修饰小分子药物的设计和应用。     

Antibody-drug conjugates: recent advances in conjugation and linker chemistries

The antibody-drug conjugate (ADC), a humanized or human monoclonal antibody conjugated with highly cytotoxic small molecules (payloads) through chemical linkers, is a novel therapeutic format and has great potential to make a paradigm shift in cancer chemotherapy. Thisnewantibody-based molecular platform enables selective delivery of a potent cytotoxic payload to target cancer cells, resulting in improved efficacy, reduced systemic toxicity, and preferable pharmacokinetics (PK)/ pharmacodynamics (PD) and biodistribution compared to traditional chemotherapy. Boosted by the successes of FDA-approved Adcetris® and Kadcyla®, this drug class has been rapidly growing along with about 60 ADCs currently in clinical trials. In this article, we briefly review molecular aspects of each component (the antibody, payload, and linker) of ADCs, and then mainly discuss traditional and new technologies of the conjugation and linker chemistries for successful construction of clinically effective ADCs. Current efforts in the conjugation and linker chemistries will provide greater insights into molecular design and strategies for clinically effective ADCs from medicinal chemistry and pharmacology standpoints. The development of site-specific conjugation methodologies for constructing homogeneousADCs is an especially promising path to improving ADC design, which will open the way for novel cancer therapeutics.     

In Vitro and In Vivo Evaluation of Cysteine and Site Specific Conjugated Herceptin Antibody-Drug Conjugates

Antibody drug conjugates (ADCs) are monoclonal antibodies designed to deliver a cytotoxic drug selectively to antigen expressing cells. Several components of an ADC including the selection of the antibody, the linker, the cytotoxic drug payload and the site of attachment used to attach the drug to the antibody are critical to the activity and development of the ADC.The cytotoxic drugs or payloads used to make ADCs are typically conjugated to the antibody through cysteine or lysine residues. This results in ADCs that have a heterogeneous number of drugs per antibody. The number of drugs per antibody commonly referred to as the drug to antibody ratio (DAR), can vary between 0 and 8 drugs for a IgG₁ antibody. Antibodies with 0 drugs are ineffective and compete with the ADC for binding to the antigen expressing cells. Antibodies with 8 drugs per antibody have reduced in vivo stability, which may contribute to non target related toxicities.In these studies we incorporated a non-natural amino acid, para acetyl phenylalanine, at two unique sites within an antibody against Her2/neu. We covalently attached a cytotoxic drug to these sites to form an ADC which contains two drugs per antibody.We report the results from the first direct preclinical comparison of a site specific non-natural amino acid anti-Her2 ADC and a cysteine conjugated anti-Her2 ADC. We report that the site specific non-natural amino acid anti-Her2 ADCs have superior in vitro serum stability and preclinical toxicology profile in rats as compared to the cysteine conjugated anti-Her2 ADCs. We also demonstrate that the site specific non-natural amino acid anti-Her2 ADCs maintain their in vitro potency and in vivo efficacy against Her2 expressing human tumor cell lines. Our data suggests that site specific non-natural amino acid ADCs may have a superior therapeutic window than cysteine conjugated ADCs.     

Potential drugs used in the antibody–drug conjugate (ADC) architecture for cancer therapy

Cytotoxic small-molecule drugs have a major influence on the fate of antibody–drug conjugates (ADCs). An ideal cytotoxic agent should be highly potent, remain stable while linked to ADCs, kill the targeted tumor cell upon internalization and release from the ADCs, and maintain its activity in multidrug-resistant tumor cells. Lessons learned from successful and failed experiences in ADC development resulted in remarkable progress in the discovery and development of novel highly potent small molecules. A better understanding of such small-molecule drugs is important for development of effective ADCs. The present review discusses requirements making a payload appropriate for antitumor ADCs and focuses on the main characteristics of commonly-used cytotoxic payloads that showed acceptable results in clinical trials. In addition, the present study represents emerging trends and recent advances of payloads used in ADCs currently under clinical trials.     

Site-specific antibody drug conjugates for cancer therapy

Antibody therapeutics have revolutionized the treatment of cancer over the past two decades. Antibodies that specifically bind tumor surface antigens can be effective therapeutics; however, many unmodified antibodies lack therapeutic activity. These antibodies can instead be applied successfully as guided missiles to deliver potent cytotoxic drugs in the form of antibody drug conjugates (ADCs). The success of ADCs is dependent on four factors—target antigen, antibody, linker, and payload. The field has made great progress in these areas, marked by the recent approval by the US Food and Drug Administration of two ADCs, brentuximab vedotin (Adcetris^®) and ado-trastuzumab emtansine (Kadcyla^®). However, the therapeutic window for many ADCs that are currently in pre-clinical or clinical development remains narrow and further improvements may be required to enhance the therapeutic potential of these ADCs. Production of ADCs is an area where improvement is needed because current methods yield heterogeneous mixtures that may include 0–8 drug species per antibody molecule. Site-specific conjugation has been recently shown to eliminate heterogeneity, improve conjugate stability, and increase the therapeutic window. Here, we review and describe various site-specific conjugation strategies that are currently used for the production of ADCs, including use of engineered cysteine residues, unnatural amino acids, and enzymatic conjugation through glycotransferases and transglutaminases. In addition, we also summarize differences among these methods and highlight critical considerations when building next-generation ADC therapeutics.     

Effects of antibody,drug and linker on the preclinical and clinical toxicities of antibody-drug conjugates

Antibody-drug conjugates (ADCs) represent a new class of cancer therapeutics. Their design involves a tumor-specific antibody, a linker and a cytotoxic payload. They were designed to allow specific targeting of highly potent cytotoxic agents to tumor cells whilst sparing normal cells. Frequent toxicities that may be driven by any of the components of an ADC have been reported. There are currently more than 50 ADCs in active clinical development, and a further ～20 that have been discontinued. For this review, the reported toxicities of ADCs were analysed, and the mechanisms for their effects are explored in detail. Methods to reduce toxicities, including dosing strategies and drug design, are discussed. The toxicities reported for active and discontinued drugs are important to drive the rational design and improve the therapeutic index of ADCs of the future.     

Antibody–drug conjugates (ADCs) for cancer therapy: Strategies,challenges, and successes

Targeted delivery of therapeutic molecules into cancer cells is considered as a promising strategy to tackle cancer. Antibody–drug conjugates (ADCs), in which a monoclonal antibody (mAb) is conjugated to biologically active drugs through chemical linkers, have emerged as a promising class of anticancer treatment agents, being one of the fastest growing fields in cancer therapy. The failure of early ADCs led researchers to explore strategies to develop more effective and improved ADCs with lower levels of unconjugated mAbs and more-stable linkers between the drug and the antibody, which show improved pharmacokinetic properties, therapeutic indexes, and safety profiles. Such improvements resulted in the US Food and Drug Administration approvals of brentuximab vedotin, trastuzumab emtansine, and, more recently, inotuzumab ozogamicin. In addition, recent clinical outcomes have sparked additional interest, which leads to the dramatically increased number of ADCs in clinical development. The present review explores ADCs, their main characteristics, and new research developments, as well as discusses strategies for the selection of the most appropriate target antigens, mAbs, cytotoxic drugs, linkers, and conjugation chemistries.     

The discovery and development of brentuximab vedotin for use in relapsed Hodgkin lymphoma and systemic anaplastic large cell lymphoma

Progress has been made recently in developing antibody-drug conjugates (ADCs) that can selectively deliver cancer drugs to tumor cells. In principle, the idea is simple: by attaching drugs to tumor-seeking antibodies, target cells will be killed and nontarget cells will be spared. In practice, many parameters needed to be addressed to develop safe and effective ADCs, including the expression profiles of tumor versus normal tissues, the potency of the drug, the linker attaching the drug and placement of the drug on the antibody, and the pharmacokinetic and stability profiles of the resulting ADC. All these issues had been taken into account in developing brentuximab vedotin (Adcetris), an ADC that recently received accelerated approval by the US Food and Drug Administration for the treatment of relapsed Hodgkin lymphoma and systemic anaplastic large cell lymphoma (ALCL). Research is under way to extend the applications of brentuximab vedotin and to advance the field by developing other ADCs with new linker and conjugation strategies.     

Novel immunoconjugates comprised of streptonigrin and 17-amino-geldanamycin attached via a dipeptide-p-aminobenzyl-amine linker system

Cytotoxic agents streptonigrin and 17-amino-geldanamycin were linked to monoclonal antibodies (mAbs), forming antibody–drug conjugates (ADCs) for antigen-mediated targeting to cancer cells. The drugs were conjugated with a linker construct that is labile to lysosomal proteases and incorporates a valine-alanine-p-aminobenzyl (PAB)-amino linkage for direct attachment to the electron-deficient amine functional groups present in both drugs. The resulting ADCs release drug following internalization into antigen-positive cancer cells. The drug linkers were conjugated to mAbs cAC10 (anti-CD30) and h1F6 (anti-CD70) via alkylation of reduced interchain disulfides to give ADCs loaded with 4 drugs/mAb. The streptonigrin ADCs were potent and immunologically specific on a panel of cancer cell lines in vitro and in a Hodgkin lymphoma xenograft model. We conclude that streptonigrin ADCs are candidates for further research, and that the novel linker system used to make them is well-suited for the conjugation of cytotoxic agents containing electron-deficient amine functional groups.