Optimizing NK Cell-Engaging Bispecific Antibody Therapy Targeting CD33

优化靶向 CD33 的 NK 细胞双特异性抗体疗法

• 批准号: 10601351
• 负责人: Roland Bruno Walter
• 金额: $ 8.36万
• 依托单位: FRED HUTCHINSON CANCER CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10601351
• 关键词: Optimizing; NK; Cell; Engaging; Bispecific

ABSTRACT CD33-targeted therapies have long been pursued in acute myeloid leukemia (AML). Longer survival of some patients treated with the antibody-drug conjugate gemtuzumab ozogamicin (GO) validates this approach, but many patients with CD33+ AML do not benefit from GO. This has prompted efforts to develop better CD33- directed therapeutics, including T cell engaging bispecific antibodies (BsAbs). Several agents have recently entered early phase clinical testing, with initial results indicating some efficacy but also substantial toxicities from cytokine-release syndrome associated with T cell activation. There is therefore increasing focus on exploring the utility of other immune cells such as natural killer (NK) cells (e.g. via engagement of CD16), which might circumvent these limitations. How CD33/CD16-directed therapy can be optimized is unknown. As one limitation of CD33-targeted therapy, CD33 antibodies (including GO) typically recognize immune-dominant epitope(s) within the membrane-distal V-set domain. In our preliminary studies with CD33V-set/CD3 BsAbs and artificial CD33 proteins, however, we have observed enhanced T cell-mediated cytotoxicity with membrane-proximal binding of CD33. We have therefore generated a series of antibodies against the membrane-proximal C2-set domain of CD33 that recognize all naturally occurring variants of CD33 (i.e. are “CD33PAN antibodies”) as basis for novel therapeutics. Our previous studies have also shown that the anti-tumor efficacy of T cell-directed BsAbs is abrogated by inhibitory T cell co-receptor signaling, e.g. via the PD-L1/PD-1 axis. We further demonstrated that the use of a paired BsAb which binds and blocks such an inhibitory signal while, in turn, providing co- stimulation to T cells (e.g. via cross-linking CD28) can convert cellular inhibition into activation and dramatically increase the efficacy of T cell engaging BsAbs. So far, the role of activating and inhibitory NK receptors and their corresponding ligands as modulators of BsAb-based NK cell therapy has not been evaluated. Based on our studies with T cell-engaging BsAbs, we hypothesize CD33/CD16-directed NK cell engaging therapy can be optimized by membrane-proximal targeting of CD33. We also predict that activating and inhibitory NK cell ligands modulate the anti-tumor efficacy of CD33/CD16 BsAbs and that, consequently, the resistance to CD33/CD16 BsAbs can be reversed by pairing with a BsAb that binds/blocks an inhibitory NK cell ligand and stimulates an activating NK cell receptor. We will test these hypotheses in well-controlled preclinical studies in vitro and in vivo. Upon completion of the proposed research, it is our expectation that we have gained critical insight into how the anti-AML efficacy of CD33/CD16 NK cell-engaging therapeutics can be maximized. Our work is anticipated to have an important positive impact because it may form the basis for optimized NK cell engaging therapeutics for patients with AML and other CD33+ disorders, for which outcomes continue to be unsatisfactory.

抽象的 长期以来在急性髓样白血病（AML）中追求了CD33靶向的疗法。某些人的生存更长 用抗体 - 药物结合物gemtuzumab ozogamicin（GO）治疗的患者验证了这种方法，但 许多CD33+ AML的患者无法从GO中受益。这促使人们努力开发更好的CD33- 定向治疗，包括与双特异性抗体（BSABS）的T细胞。最近有几个代理商 进入早期临床测试，最初的结果表明有效，但也来自 与T细胞激活相关的细胞因子释放综合征。因此，越来越关注探索 其他免疫细胞的效用，例如天然杀手（NK）细胞（例如，通过CD16的参与） 规避这些限制。如何优化CD33/CD16指导的治疗尚不清楚。作为一个限制 CD33靶向疗法的CD33抗体（包括GO）通常识别免疫主导性发作（S） 在膜遥距V-stet域中。在我们使用CD33V-SET/CD3 BSAB和人工的初步研究中 但是，CD33蛋白质已经观察到伴有膜 - 果实的T细胞介导的细胞毒性增强 CD33的结合。因此，我们已经生成了一系列针对膜的抗体 CD33的域识别所有天然发生的CD33变体（即“ CD33PAN抗体”）作为基础 用于新型疗法。我们以前的研究还表明，T细胞指导的BSAB的抗肿瘤效率 被抑制性T细胞共受体信号所消除，例如通过PD-L1/PD-1轴。我们进一步证明了 使用配对的BSAB结合并阻止这种抑制性信号的使用，然后提供共同 对T细胞的刺激（例如，通过交联CD28）可以将细胞抑制转化为激活，并急剧地转化 提高与BSAB的T细胞的效率。到目前为止，激活和抑制性NK受体的作用及其 尚未评估相应的配体作为基于BSAB的NK细胞疗法的调节剂。基于我们 对T细胞吸引BSABS的研究，我们假设CD33/CD16指导的NK细胞参与疗法可以是 通过CD33的膜核靶向优化。我们还预测激活和抑制性NK细胞配体 调节CD33/CD16 BSAB的抗肿瘤效率，因此，对CD33/CD16的抗性 可以通过与BSAB配对（结合/阻断抑制性NK细胞配体）并刺激A的BSAB来逆转BSAB 激活NK细胞受体。我们将在体外和体内进行良好控制的临床前研究中检验这些假设。 拟议的研究完成后，我们期望我们对如何获得批判性见解 CD33/CD16 NK细胞启动疗法的抗AML效率可以最大化。我们的工作预计会 具有重要的积极影响，因为它可能构成优化NK细胞参与疗法的基础 AML和其他CD33+疾病患者，结果仍然不令人满意。