Development of low-cost, field-ready nanobodies against snake venom

项目摘要 蛇咬伤是全球范围内最大和最顽固的公共卫生问题之一。每一年， 多达500万人将遭受毒蛇咬伤，造成约12.5万人死亡，40万人死亡， 留下永久性的身体残疾。美国每年发生近8,000起蛇咬伤事件。的区域 受影响最大的是亚洲、非洲、拉丁美洲和大洋洲，在这些地区，蛇咬伤具有很高的社会经济影响 对当地和全球经济的影响。截至2017年，世界卫生组织已将蛇咬伤列为A类被忽视的疾病 热带病。蛇咬伤患者的治疗方法是动物抗蛇毒血清，世纪以来， 由大型哺乳动物（马和羊）的全血清或纯化抗体组成， 用蛇毒进行超免疫这些抗蛇毒血清只含有一小部分有效毒液 特异性抗体，需要多次给药，可在患者中引起不良免疫原性效应。抗蛇毒 也具有相对较高的批次间差异，其功效在很大程度上是物种特异性的，需要匹配 免疫用的物种和需要中和的毒液之间的关系。抗蛇毒血清的经济学 制造业在扩大盈利能力方面面临挑战，导致供应稀缺且不可靠。进一步 使问题复杂化的是对冷链储存和配送的依赖以及由此产生的可用性不足 到偏远地区的蛇咬伤受害者那里发生了大量的毒液。尽管存在这些问题， 是少数尚未进入主流生物制剂现代时代的生物疗法之一，尽管 存在压倒性的大量患者群体。 为了解决蛇咬伤的复杂医疗和经济要求，我们建议使用 单域抗体的寡克隆混合物，也称为纳米抗体（Nbs）。这些抗体片段（15 分子量为kDa）是骆驼科动物或鲨鱼抗体的可变重链区（VHH），具有几个 该空间的吸引人的特性，包括低免疫原性、高生物分布和组织渗透性、低 规模化生产的成本和可调的药代动力学。NBS通常也是高度热稳定的， 为急需的发展中国家提供无障碍环境。NBS具有长而灵活的互补决定区域 在一些实施方案中，抗-CDRs（CDR）可以增加结合这些毒素上的保守或隐蔽表位的可能性，从而允许抗-CDRs（CDRs）结合。 广泛的物种覆盖对泛特异性至关重要。为此，Venomyx Therapeutics，Inc.是工作在 与UCSD的Chang实验室合作，开发一个强大的平台来发现综合进化的Nbs 针对感兴趣的毒液靶标的高亲和力和功效，可以使用SENs。再加上蛇毒的专业知识 在Venomyx，我们将生产低成本、耐热、广泛有效的抗蛇毒毒素的Nbs作为先导 用于未来的开发、临床前测试和最终的人体试验，以中和蛇咬伤的毒液。

PROJECT SUMMARY Snakebite constitutes one of the largest and most tenacious public health issues on a global scale. Every year, up to 5 million people will suffer snakebite envenomation, causing approximately 125,000 deaths and 400,000 left with permanent physical disability. Nearly 8,000 snakebites occur in the United States each year. The regions most affected are in Asia, Africa, Latin America, and Oceania where snakebite has a high socioeconomic impact on both the local and global economies. As of 2017, the WHO has labeled snakebite as a Category A Neglected Tropical Disease. Therapies for snakebite victims are animal-based antivenoms, which for over a century have consisted of the whole sera or purified antibodies of large mammals (horses and sheep) that have been hyperimmunized with snake venoms. These antivenoms contain a relatively small fraction of effective venom- specific antibodies, requiring multiple doses that can cause adverse immunogenic effects in patients. Antivenom also has relatively high batch-to-batch variation and its efficacies are largely species-specific, requiring a match between the species used in immunization and the venom in need of neutralization. The economics of antivenom manufacture are challenging to scale to profitability, leading to scarce and unreliable supplies. Further complicating the issue is the reliance on cold chain storage and distribution and consequential lack of availability to snakebite victims in remote locations where the bulk of envenomations occur. Despite these issues, antivenom is one of the few biological therapies that has yet to enter the modern era of mainstream biologics, despite the presence of an overwhelmingly large patient population. In order to address the complex medical and economic requirements of snakebite, we propose the use of an oligoclonal mixture of single-domain antibodies, also known as nanobodies (Nbs). These antibody fragments (15 kDa in molecular weight) are the variable heavy chain regions (VHH) of camelid or shark antibodies with several attractive properties for the space, including low immunogenicity, high biodistribution and tissue penetration, low cost of scaled production, and tunable pharmacokinetics. Nbs are also often highly thermostable, allowing for accessibility in much-needed developing countries. Nbs have long, flexible complementarity-determining regions (CDRs) which can increase the likelihood of binding conserved or cryptic epitopes on these toxins, allowing for broad species coverage critical to pan-specificities. Towards this end, Venomyx Therapeutics, Inc. is working in collaboration with the Chang lab at UCSD to exploit a powerful platform to discover Synthetically Evolved Nbs (SENs) for high affinity and efficacy against venom targets of interest. Together with the snake venom expertise at Venomyx, we will generate low-cost, thermostable, broadly-effective Nbs against snake venom toxin as leads for future development, preclinical testing, and eventual human trials to neutralize venom from snakebite.