Maximizing Antibody Drug Conjugate Efficacy through Multiple Mechanisms of Action

摘要 最近FDA批准了另外两种抗体药物缀合物（ADC），这突出了临床成功和 在这类机构中成长。然而，尽管有这些批准，新ADC的流失率仍然很高， 在肿瘤学应用中，还没有用于实体瘤的ADC能够重复ado的成功， 曲妥珠单抗-美坦新偶联物（T-DM 1）。已经进行了大量的努力来改善抗体和靶向。 选择、缀合位点、接头稳定性和有效负载性质（效力、旁观者效应等），而这些 这些改进将有益于下一代化合物。然而，根本问题仍然是如何 来设计一种临床上有效的药剂具体而言，多重因素之间的相对贡献和相互作用 这些药物的作用机制（受体信号传导阻断、有效载荷效力和Fc效应器功能） 仍然未知。长期目标是了解这些复杂药物的基本特性， 足够的细节以合理地将抗体、接头和有效载荷与特定靶标组合（在选择的实施方案中）。 患者群体），以在癌症和非肿瘤应用中获得最大临床功效。的目标 这一建议是为了定量地了解抗原阳性反应中直接有效载荷效应的相对贡献， 在抗原阴性细胞中的旁观者有效载荷效应，以及Fc效应子功能在确定 抗体药物缀合物的功效。使用近红外荧光成像和流动相结合 通过流式细胞术，可以计算每个细胞的完整和降解（触发有效载荷释放）ADC的绝对数量。 测定通过将这些结果与药效学标志物（例如，烷基化的DNA损伤标志物）配对， 由于ADC（直接杀伤和旁观者杀伤）的递送和功效可以用单次免疫荧光定量，因此ADC的递送和功效（直接杀伤和旁观者杀伤两者）可以用单次免疫荧光定量。 体内细胞分辨率。将使用不同比例的ADC与未缀合的抗体的共施用以 控制组织分布以改变直接与间接杀伤。这些研究将在两个国家进行， 免疫受损和免疫活性（同源）小鼠模型以确定益处（或 免疫系统的激活。通过将单细胞测量结果与金标准进行比较 临床前疗效（肿瘤生长曲线），将确定每种机制的相对贡献。 这项工作的结果将使新型ADC的合理设计成为可能，而不是测试无数的ADC。 a）选择具有更均匀表达的靶标， 如果直接靶向占主导地位，则ADC内化，B）ADC的最佳理化性质和分布， 旁观者有效载荷，如果旁观者效应起主要作用，或c）免疫细胞的激活和募集 如果需要免疫细胞募集，则通过共同治疗、Fc工程化和/或给药方案。一 作为单一疗法失败的大量单克隆抗体在体内处于休眠状态， 制药公司。通过利用有效载荷和连接体化学的进步， 根据该建议，可以快速加速新的临床成功ADC的开发。

Abstract The recent FDA approval of two more antibody drug conjugates (ADCs) highlights the clinical success and growth in this class of agents. Despite these approvals, however, the attrition rate for new ADCs remains high, and in oncology applications, no ADC for solid tumors has yet been able to repeat the success of ado- trastuzumab emtansine (T-DM1). A substantial effort has been exerted to improve the antibody and target selection, conjugation site, linker stability, and payload properties (potency, bystander effects, etc.), and these improvements will benefit the next generation of compounds. However, fundamental questions remain on how to design a clinically effective agent. Specifically, the relative contribution and interaction between the multiple mechanisms of action of these drugs (receptor signaling blockade, payload efficacy, and Fc effector functions) remains unknown. The long-term goal is to understand the fundamental properties of these complex drugs in sufficient detail to rationally combine the antibody, linker, and payload with a particular target (in a select patient population) for maximum clinical efficacy in both cancer and non-oncologic applications. The goal for this proposal is to quantitatively understand the relative contribution of direct payload effects in antigen positive cells, bystander payload effects in antigen negative cells, and the role of Fc-effector functions in determining efficacy with antibody drug conjugates. Using a combination of near-infrared fluorescence imaging and flow cytometry, the absolute number of intact and degraded (triggering payload release) ADCs per cell can be determined. By pairing these results with pharmacodynamic markers (e.g. DNA damage markers of alkylating agents), the delivery and efficacy of the ADC (both direct and bystander killing) can be quantified with single cell resolution in vivo. Co-administration of varying ratios of ADC with unconjugated antibody will be used to control the tissue distribution to vary direct versus indirect killing. The studies will be conducted in both an immunocompromised and immunocompetent (syngeneic) mouse model to determine the benefit (or requirement) for immune system activation. By comparing the single-cell measurements with the gold standard of preclinical efficacy (tumor growth curves), the relative contribution of each mechanism will be determined. The outcome of the work will enable the rational design of novel ADCs rather than testing the myriad combinations in vivo by focusing development on a) selection of targets with more uniform expression and ADC internalization if direct targeting predominates, b) optimal physicochemical properties and distribution of bystander payloads if bystander effects plays a major role, or c) activation and recruitment of immune cells through co-therapy, Fc engineering, and/or dosing regimens if immune cell recruitment is necessary. A significant number of monoclonal antibodies that failed as monotherapies are sitting dormant within pharmaceutical companies. By leveraging advances in payload and linker chemistry with the knowledge from this proposal, development of new clinically successful ADCs can be rapidly accelerated.