A Novel Humanized Tetra-specific Antibody against Clostridium difficile Infection

摘要 抗生素耐药性是一个全球性的公共卫生危机。抗生素耐药的艰难梭菌负责 美国每年有超过29，000人死亡，这种感染对公共卫生构成了紧迫威胁 国际吧最令人关注的是C.艰难梭菌感染（CDI）和疾病的严重程度迅速 近年来由于高毒力和耐药性菌株的出现，CDI是由 由两种主要毒素TcdA和TcdB引起，没有这两种毒素，细菌是无毒的。目前的标准治疗， 抗生素是次优的，并且由于肠道微生物群的破坏而伴有高复发率。 使用抗体靶向主要毒力因子的方法代表了针对 CDI.然而，最先进的治疗性抗体bezlotoxumab，一种抗TcdB单克隆抗体，来自 默克公司，仅在最近一期研究中显示出与抗生素非达霉素在减少CDI复发方面具有相当的效果 第三次审判。这种不太理想的功效可能是由于靶向毒素的单一表位和低效力 的抗体。我们开发了一种基于4个VHH的新型四特异性人源化抗体FZ 001 针对不同的抗原决定基每种毒素上有两个FZ 001有效和广泛地中和两种毒素 不同的临床分离株，并证明对原发性和复发性 小鼠中的CDI。已构建了具有高表达水平FZ 001的cGMP级CHO系。在 响应RFA-AI-16-034，我们建议开发细胞培养参数和分析测定， 后续生产工艺，以生成用于GLP毒理学的FZ 001。该项目将使 生成化学、生产和控制（CMC）的关键数据，用于未来的IND申报和I期研究 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.