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.

滤泡性淋巴瘤（FL）以肿瘤性B细胞增殖为特征，在美国每年有15，000例新发病例。 标准治疗线导致FL无病生存期逐渐缩短。中位总生存期（OS） 由于新的药物整合到FL治疗模式中，FL的治疗效果得到了改善。因此，至关重要的是， 新的药物，以实现更好的疾病控制。CD 20在恶性FL细胞上表达，靶向CD 20起关键作用 单克隆抗CD 20抗体利妥昔单抗在治疗FL中的作用， 其作用机制包括抗体依赖性细胞毒性（ADCC） 和补体依赖性细胞毒性（CDC）。许多报道已经确定CA 125是肿瘤微环境 在一些癌症患者的血清中可以检测到升高的因子，包括37%的FL患者。最近的证据 表明CA-125抑制免疫治疗的临床效果：在一项III期研究中，血清CA-125水平低的患者， 与接受farletuzumab治疗的患者相比，接受farletuzumab治疗的sCA 125（sCA 125）患者具有上级PFS和OS， sCA 125水平高。在另一项检测amatuximab的研究中，sCA 125水平低的患者的PFS和OS上级， 与sCA 125水平高的患者相比。Navrogen的研究小组发现sCA 125抑制farletuzumab， amatuximab的体外ADCC和CDC，以及sCA 125抑制其与Fc受体和C1 q的结合。这些 这些影响是由于CA 125直接结合法莱珠单抗和阿马妥昔单抗，改变了它们的Fc结构域。ADCC扮演一个 Fc γ RIIIa（CD 16 a）多态性分析表明利妥昔单抗在临床效果中的重要作用 在FL患者中。值得注意的是，sCA 125水平与FL患者对利妥昔单抗治疗的反应相关， 低CA-125水平的FL患者的5年PFS更优。Navrogen的研究小组表明，利妥昔单抗的ADCC和CDC是 通过与利妥昔单抗结合，在体外被sCA 125抑制。CA 125抑制利妥昔单抗活性的机制 代表了其治疗FL的全部潜力的障碍。拟议的6个月计划旨在消除这一障碍 屏障解决方案是设计一种改进的利妥昔单抗版本，它是CA 125难治的。CA 125结合位点为： Navrogen的团队将范围缩小到重链序列，这些序列经过突变产生突变抗体 已经失去了CA 125结合位点，成为CA 125难治性。同样，该计划的目标是设计一个版本的 利妥昔单抗是CA 125难治性的，使用称为阻断去除免疫球蛋白技术的平台，或 布里特。目标1里程碑包括i）利妥昔单抗BRITE文库的产生及其筛选和ii）利妥昔单抗的选择 CA 125难治性和保留CD 20结合的变体（命名为NAV-006）。目标2里程碑是证明 NAV-006在高水平sCA 125存在下增强ADCC和CDC细胞毒性。利妥昔单抗变体NAV-006 在存在以下物质的情况下，根据其增强的ADCC和CDC细胞毒性， 高水平的CA 125（>100%更有效）、结合亲和力（如果有任何损失，不超过5倍）和CA 125损失 相互作用（>90%）。Navrogen的团队在开发生物药物方面的经验及其临床知识 相关的CA 125生物学大大降低了与实现本提案的特定目标相关的风险。