A Novel Humanized Tetra-specific Antibody against Clostridium difficile Infection

摘要 抗菌素耐药性是一个全球性的公共卫生危机。难辨梭状芽胞杆菌对抗生素耐药 美国每年有超过2.9万人死亡，这种感染对公共健康构成了紧急威胁 全世界。最令人担忧的是艰难梭菌感染(CDI)的发病率和疾病严重程度迅速上升。 近年来，由于出现了超强毒力和抗药性菌株，感染人数有所增加。CDI是由 由两种主要毒素TcdA和TcdB引起的，没有这两种毒素，细菌是无毒的。当前的标准治疗方法是 抗生素是次佳的，并且由于肠道微生物区系的破坏而伴随着高复发率。 使用抗体靶向主要毒力因子的方法代表了一种新的治疗方案 CDI公司。然而，最先进的治疗性抗体苯洛昔单抗，一种来自 默克在减少CDI复发方面仅显示出与抗生素fidaxomicin相当的近期效果 III试验。这种不太理想的效果很可能是由于靶向单一的毒素表位和低效力所致。 抗体的一部分。我们开发了一种基于4个VHH的新型四特异性人源化抗体FZ001 目标是不同的表位，每种毒素上有两个表位。FZ001能有效且广泛地中和这两种毒素 不同的临床分离株，对初发和复发均有有效的治疗效果 CDI对小鼠的影响。构建了高表达FZ001的cGMP级CHO细胞系。在……里面 响应RFA-AI-16-034，我们建议开发细胞培养参数和分析方法，并 后续制造工艺，以产生用于GLP毒理学的FZ001。该项目将允许 为未来的IND备案和第一阶段生成化学、制造和控制(CMC)的关键数据 临床试验。

Abstract Antibacterial resistance is a global public health crisis. Antibiotic-resistant Clostridium difficile is responsible for more than 29,000 deaths in the US each year and the infection represents an urgent threat to public health worldwide. Of most concern is that the incidence of C. difficile infection (CDI) and disease severity is rapidly increasing in recent years due to the emergence of hypervirulent and antibiotic-resistant strains. CDI is caused by two major toxins TcdA and TcdB, absent which the bacterium is avirulent. Current standard treatment with antibiotics is sub-optimal and accompanied by a high recurrence rate due to the disruption of gut microbiota. Approaches using antibodies to target the major virulence factors represent a new treatment option against CDI. However, the most advanced therapeutic antibody bezlotoxumab, an anti-TcdB monoclonal antibody from Merck, only showed a comparable effect as antibiotic fidaxomicin on reducing CDI recurrence in recent Phase III trials. This less-than-desirable efficacy is likely due to targeting a single epitope of the toxin and low potency of the antibody. We have developed a novel tetra-specific, humanized antibody FZ001 based on 4 VHHs targeting distinct epitopes, two on each of the toxins. FZ001 potently and broadly neutralizes both toxins from different clinical isolates and demonstrates a potent therapeutic efficacy against both primary and recurrent CDI in mice. cGMP-grade CHO lines have been constructed with a high expression level of FZ001. In response to RFA-AI-16-034, we propose to develop cell culture parameters and analytic assays and subsequent manufacturing process in order to generate FZ001 for GLP toxicology. This project will allow the generation of the critical data of chemical, manufacturing, and control (CMC) for future IND filing and Phase I clinical trials.