Next-generation anti-CD20 rituximab antibody that is engineered to be resistant to the immuno-suppressive effect mediated by the tumor-shed antigen, CA125

下一代抗 CD20 利妥昔单抗抗体，经过改造可抵抗肿瘤脱落抗原 CA125 介导的免疫抑制作用

• 批准号: 10045037
• 负责人: Luigi Grasso
• 金额: $ 6.9万
• 依托单位: NAVROGEN, INC.
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10045037
• 关键词: Address; Affinity; Antibodies; Antibody Affinity; Antibody-Dependent Enhancement; Antigens; B-Lymphocytes; Benchmarking; Binding; Binding Sites; Biological; Biology; Budgets; CA-125 Antigen; CD20 Antigens; Cancer Patient; Cell Survival; Cells; Clinical; Complement; Complement 1q; Complement component C1; Complement-Dependent Cytotoxicity; Disease-Free Survival; Effectiveness; Effector Cell; Engineering; Enzyme-Linked Immunosorbent Assay; FCGR3A gene; Fc Receptor; Fc domain; Flowcharts; Follicular Lymphoma; Funding; Future; Generations; Genetic Polymorphism; Goals; Human; Humoral Immunities; Immunoglobulin Variable Region; Immunoglobulins; Immunosuppression; Immunotherapy; In Vitro; Jurkat Cells; Knowledge; Lead; Libraries; Lymphoma cell; MS4A1 gene; Malignant - descriptor; Measures; Mediating; Medical; Methods; Modeling; Mutagenesis; Mutate; Mutation; N-terminal; NCAM1 gene; Names; Parents; Patients; Peptides; Pharmaceutical Preparations; Phase; Play; Preparation; Production; Productivity; Progression-Free Survivals; Protein Isoforms; Proteins; Raji Cell; Reading; Refractory; Reporting; Resistance; Risk; Role; Serum; Source; Technology; Testing; Therapeutic; Time; Tumor Antigens; Validation; Variant; anti-CD20; anti-cancer; antibody-dependent cell cytotoxicity; base; clinical effect; clinically relevant; cytotoxicity; cytotoxicity test; disorder control; experience; follow-up; immunogenicity; improved; in vivo; luminescence; mutant; neoplastic; next generation; nonlinear regression; novel; novel therapeutics; phase 3 study; prevent; response; rituximab; screening; tositumomab; tumor; tumor microenvironment

Follicular lymphoma (FL) is characterized by proliferation of neoplastic B cells, with 15,000 new cases/year in US. Standard therapy lines result in progressively shorter periods of FL disease-free survival. The median overall survival (OS) for FL has improved due to novel agents integrated into the FL therapeutic paradigm. Therefore, it is critical to advance novel drugs to achieve better disease control. CD20 is expressed on malignant FL cells and targeting CD20 plays a key role in the treatment of FL, with monoclonal anti-CD20 antibody rituximab having markedly improved the progression-free survival (PFS) and OS. Its mechanism of action includes antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Many reports have established CA125 as a tumor–microenvironment factor that can be detected elevated in serum of some cancer patients, including 37% of FL patients. Recent evidence show that CA125 dampens immunotherapy clinical effects: In a Phase III study, patients with low levels of serum CA-125 (sCA125) had superior PFS and OS when treated with farletuzumab, compared with farletuzumab-treated patients with high sCA125 levels. In another study testing amatuximab, patients with low sCA125 levels had superior PFS and OS as compared with patients with high sCA125 levels. Navrogen’s team discovered that sCA125 inhibits farletuzumab’s and amatuximab’s ADCC and CDC in vitro, as well as that sCA125 inhibits their engagement with Fc receptor and C1q. These effects are due to CA125 direct binding to farletuzumab and amatuximab, which alters their Fc domain. ADCC plays an important role in the clinical effect of rituximab as suggested by the analysis of Fc gamma RIIIa (CD16a) polymorphisms in FL patients. It is compelling to note that sCA125 levels correlated with responses to rituximab treatment in FL, with superior 5-year PFS in FL patients having low CA-125 levels. Navrogen’s team showed that rituximab’s ADCC and CDC is inhibited in vitro by sCA125 via its binding to rituximab. This mechanism by which CA125 inhibits rituximab activity represents a barrier to its full potential for the treatment of FL. The proposed 6-month plan aims at removing this barrier. The solution is to engineer an improved rituximab version that is CA125-refractory. CA125 binding site was narrowed down by the Navrogen’s team to heavy chain sequences which were mutated to generate a mutant antibody that has lost CA125 binding site becoming CA125-refractory. Similarly, this plan’s aim is to engineer a version of rituximab that is CA125-refractory, using a platform referred to as block-removed immunoglobulin technology, or BRITE. Aim 1 milestones include i) generation of rituximab BRITE library and its screening and ii) selection of rituximab variants that are CA125-refractory and retain CD20 binding (named NAV-006). Aim 2 milestone is to demonstrate NAV-006’s enhanced ADCC and CDC cytotoxicity in the presence of high levels of sCA125. Rituximab variant NAV-006 will be benchmarked against parent rituximab in terms of its enhanced ADCC and CDC cytotoxicity in the presence of high levels of CA125 (>100% more potent), binding affinity (if any loss, no greater than a factor of 5), and loss of CA125 interaction (>90%). Navrogen’s team experience with developing biological drugs and its knowledge of clinically relevant CA125 biology greatly mitigates the risks associated with achieving the specific objectives of this proposal.

卵泡淋巴瘤（FL）的特征是肿瘤B细胞的增殖，美国/年有15,000例新病例。 标准治疗线导致无FL无病生存期逐渐缩短。总体生存中位数（OS） FOL由于整合到FL治疗范式中的新药物而改善了。因此，进步至关重要 新的药物以获得更好的疾病控制。 CD20在恶性FL细胞上表达，靶向CD20弹奏钥匙 用单克隆抗CD20抗体利妥昔单抗显着改善了FL的作用 无进展生存（PFS）和OS。它的作用机理包括抗体依赖性细胞细胞毒性（ADCC） 和补体依赖性细胞毒性（CDC）。许多报告已将CA125建立为肿瘤 - 微环境 在某些癌症患者的血清中可以检测到的因素，其中包括37％的FL患者。最近的证据 表明CA125抑制免疫疗法临床效果：在一项III期研究中，血清CA-125的患者较低 （SCA125）用法勒珠单抗治疗时具有优越的PFS和OS 高SCA125水平。在另一项研究Amatuximab的研究中，SCA125水平较低的患者的PFS和OS较高 与SCA125水平高的患者相比。 Navrogen的团队发现SCA125抑制了Farletuzumab和 Amatuximab在体外的ADCC和CDC，以及SCA125抑制了它们与FC受体和C1Q的互动。这些 效果是由于CA125与Farletuzumab和Amatuximab的直接结合，这些结合改变了其FC结构域。 ADCC扮演一个 正如FC伽马病（CD16A）多态性分析所暗示的利妥昔单抗临床作用中的重要作用 在FL患者中。令人信服的是，SCA125水平与FL中对利妥昔单抗治疗的反应相关， CA-125水平较低的FL患者的5年PFS上升。 Navrogen的团队表明Rituximab的ADCC和CDC是 SCA125通过与利妥昔单抗结合在体外抑制。 CA125抑制利妥昔单抗活性的这种机制 代表了其对FL治疗的全部潜力的障碍。拟议的6个月计划旨在删除此事 障碍。解决方案是为CA125-侵犯的改进的利妥昔单抗版本设计。 CA125结合位点是 由Navrogen的团队缩小到重链序列，该序列被突变以产生突变抗体 这已经失去了CA125结合位点成为CA125-侵犯。同样，该计划的目的是设计 利妥昔单抗是CA125-剥夺的，使用称为阻滞性免疫球蛋白技术的平台或 布莱斯。 AIM 1里程碑包括i）生成利妥昔单抗Brite库及其筛选和ii）选择利妥昔单抗 Ca125-侵犯并保留CD20结合的变体（命名为NAV-006）。 AIM 2里程碑是证明 在高水平的SCA125存在下，NAV-006增强了ADCC和CDC细胞毒性。利妥昔单抗变体NAV-006 在存在下的ADCC和CDC细胞毒性方面，将针对父母利妥昔单抗进行基准测试。 高水平的CA125（> 100％的电势），结合亲和力（如果有任何损失，不超过5倍）和CA125的损失 相互作用（> 90％）。 Navrogen的团队在开发生物药物及其临床知识方面的经验 相关的CA125生物学大大减轻了与实现该提案的具体目标相关的风险。