Pre-Clinical Development of a Humanized Anti-CD47 Antibody with Anti-Cancer Therapeutic Potential.
Pre-Clinical Development of a Humanized Anti-CD47 Antibody with Anti-Cancer Therapeutic Potential.
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DOI：
10.1371/journal.pone.0137345
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Majeti R
中科院分区：
文献类型：
--
作者：
Liu J;Wang L;Zhao F;Tseng S;Narayanan C;Shura L;Willingham S;Howard M;Prohaska S;Volkmer J;Chao M;Weissman IL;Majeti R
CD 47是广泛表达的细胞表面蛋白，其作为由先天免疫系统的细胞（例如巨噬细胞和树突细胞）介导的吞噬作用的调节剂发挥作用。CD 47作为这些先天性免疫细胞上的受体SIRP-α的配体，SIRP-α反过来传递吞噬作用的抑制信号。我们先前发现原代人急性髓性白血病（AML）干细胞上CD 47的表达增加，并证明了针对CD 47的阻断性单克隆抗体能够吞噬和消除AML、非霍奇金淋巴瘤（NHL）和异种移植模型中的许多实体瘤。在这里，我们报告了一种人源化抗CD 47抗体的开发，该抗体具有有效的功效和良好的毒代动力学特性，可作为候选治疗药物。制备了一种新的抗人CD 47单克隆抗体5 F9，并通过将其互补决定区（CDR）移植到人IgG 4形式上来进行抗体人源化。所得人源化5 F9抗体（Hu 5 F9-G4）以8 nM亲和力结合单体人CD 47。Hu 5 F9-G4在体外诱导原代人AML细胞的有效巨噬细胞介导的吞噬作用，并在体内完全根除人AML，导致患者来源的异种移植物的长期无病存活。此外，Hu 5 F9-G4与利妥昔单抗协同作用，消除NHL植入并治愈异种移植小鼠。最后，在非人灵长类动物中的毒代动力学研究显示，Hu 5 F9-G4可以以能够实现潜在治疗血清水平的剂量安全地静脉内施用。因此，Hu 5 F9-G4正在被积极开发用于患有AML和实体瘤的患者并且已经进入临床试验（ClinicalTrials.gov标识符：NCT 02216409）。
CD47 is a widely expressed cell surface protein that functions as a regulator of phagocytosis mediated by cells of the innate immune system, such as macrophages and dendritic cells. CD47 serves as the ligand for a receptor on these innate immune cells, SIRP-alpha, which in turn delivers an inhibitory signal for phagocytosis. We previously found increased expression of CD47 on primary human acute myeloid leukemia (AML) stem cells, and demonstrated that blocking monoclonal antibodies directed against CD47 enabled the phagocytosis and elimination of AML, non-Hodgkin’s lymphoma (NHL), and many solid tumors in xenograft models. Here, we report the development of a humanized anti-CD47 antibody with potent efficacy and favorable toxicokinetic properties as a candidate therapeutic. A novel monoclonal anti-human CD47 antibody, 5F9, was generated, and antibody humanization was carried out by grafting its complementarity determining regions (CDRs) onto a human IgG4 format. The resulting humanized 5F9 antibody (Hu5F9-G4) bound monomeric human CD47 with an 8 nM affinity. Hu5F9-G4 induced potent macrophage-mediated phagocytosis of primary human AML cells in vitro and completely eradicated human AML in vivo, leading to long-term disease-free survival of patient-derived xenografts. Moreover, Hu5F9-G4 synergized with rituximab to eliminate NHL engraftment and cure xenografted mice. Finally, toxicokinetic studies in non-human primates showed that Hu5F9-G4 could be safely administered intravenously at doses able to achieve potentially therapeutic serum levels. Thus, Hu5F9-G4 is actively being developed for and has been entered into clinical trials in patients with AML and solid tumors (ClinicalTrials.gov identifier: NCT02216409).