Potency of cryopreserved, irradiated sporozoite vaccine

冷冻保存、辐照子孢子疫苗的效力

• 批准号: 6854539
• 负责人: STEPHEN Lev HOFFMAN
• 金额: $ 29.64万
• 依托单位: SANARIA, INC.
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-02-15 至 2006-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6854539
• 关键词: Plasmodium; Plasmodium falciparum; antigens; attenuated microorganism; circumsporozoite protein; cryopreservation; drug design /synthesis /production; laboratory mouse; malaria vaccines; method development; radiation; radiation dosage; spores; vaccine development; vaccine evaluation

DESCRIPTION (provided by applicant): Malaria causes an estimated 500 million clinical cases and up to 2.7 million deaths annually, is responsible for a loss of greater than 1% of GDP in Africa annually, and is a serious concern for travelers and military personnel. Sanada's goal is to develop and commercialize an attenuated Plasmodium falciparum sporozoite vaccine for two primary markets with a potential for > $1 billion annual revenues; 1) Travelers from the developed world and 2) Infants and young children in the developing world. In limited trials, this type of immunization has been shown to protect greater than 90% of human volunteers against experimental P. falciparum challenge, protect for greater than 10 months after last immunization, and protect against heterologous challenge. No other experimental malaria vaccine under development has been shown to approach these performance characteristics. Heretofore it has been considered impractical to develop such a vaccine, in large part because volunteers have been immunized by the bite of infected mosquitoes, and mice by intravenous (IV) administration of sporozoites. All findings in humans with irradiated sporozoites have been anticipated by studies in mice with rodent malaria, and mice have now been shown to be 100% protected by subcutaneous administration (a practical route) of radiation- attenuated P. yoeii sporozoites and, in earlier published reports, by IV administration of cryopreserved (-75 degrees C) P. berghei sporozoites (stable for many months). The primary goal of this project is to develop a method for cryopreserving and irradiating P. falciparum sporozoites acceptable for the manufacturing process for an investigational new drug (IND) application to the FDA. Studies will be done initially with the rodent malaria parasite, P. yoelii because all findings will be able to be assessed in vitro and in vivo in mice. Findings in the P. yoelii system will be used as the foundation for applying similar methods to the development of a P. falciparum vaccine for humans using techniques that will produce an optimized immunogen that meets all regulatory standards. Work is in progress to optimize the method of administration of radiation attenuated P. yoelii sporozoites and to demonstrate that immunization in the skin or muscle with cryopreserved P. yoelii sporozoites induces protective immunity. However, the methods of radiation attenuation currently in use are the same as those used 30 - 40 years ago. Additionally, there have been no advances in methods of cryopreservation for sporozoites in over 20 years. None of the methods currently in use for radiation attenuation or cryopreservation of sporozoites would be suitable for the manufacture of a vaccine for human use. The optimal time point to administer the irradiating dose to sporozoites would be after they are frozen, but there are no data available regarding this approach to cryopreservation. In this project all aspects of the radiation attenuation process will be optimized, including source of radiation, amount of radiation, length of time of irradiation, container in which the radiation is performed, and documentation of radiation exposure (dosimetry) in order to establish a basis for a cGMP process. In addition, studies will be done to determine if radiation of infected mosquitoes, freshly dissected sporozoites, or frozen sporozoites provides the best immunogen - the latter being preferable from a vaccine production perspective. Furthermore, the methods of cryopreservation and thawing will be optimized so as to ensure that a vaccine is stable for at least 6 months. The goal is to deliver a defined method to produce an optimized immunogen that comprises radiation-attenuated/cryopreserved P. falciparum sporozoites, that meets all regulatory standards. The project will also provide a method for cryopreserving unirradiated sporozoites that could be used to challenge volunteers by injection with P. falciparum in vaccine studies worldwide.

描述（由申请人提供）：疟疾估计导致5亿次临床病例，每年270万例死亡，每年导致非洲损失超过GDP的1％，这是旅行者和军事人员的严重关注。 Sanada的目标是开发和商业化两种主要市场的衰减疟原虫孢子虫疫苗，年收入可能超过10亿美元； 1）来自发达国家的旅行者和2）发展中国家的婴儿和幼儿。在有限的试验中，这种免疫已被证明可以保护大于90％的人类志愿者免受实验性恶性疟原虫的挑战，防止最后一次免疫后10个月以上，并防止异源挑战。未发育中的其他实验性疟疾疫苗可用于这些性能特征。迄今为止，开发这种疫苗被认为是不切实际的，这在很大程度上是因为志愿者已经被感染的蚊子咬伤了，而小鼠则被静脉内（IV）孢子孢子施用。在患有啮齿动物疟疾的小鼠的研究中，人们已经预计，人类中的所有发现都已预计，现在已经显示出，小鼠受到皮下给药（一种实际途径（一种实际途径）的保护 - 辐射p。p.yoeii sporozoites的辐射（一种实际途径）几个月）。 该项目的主要目的是开发一种方法，用于用于对FDA的研究新药（IND）申请的制造过程可接受的冷冻水平和辐照。最初将使用啮齿动物疟原虫P. yoelii进行研究，因为所有发现都可以在小鼠的体外和体内进行评估。 P. yoelii系统中的发现将用作使用类似方法，用于将类似方法用于为人类开发的人类开发，该技术使用将产生符合所有调节标准的优化免疫原。正在进行的工作，以优化辐射减毒的孢子孢子虫的施用方法，并证明皮肤或肌肉中具有冷冻的p. yoelii孢子菌的免疫可诱导保护性免疫。但是，目前正在使用的辐射衰减方法与30至40年前使用的方法相同。此外，在20多年来，在孢子虫的冷冻保存方法方面没有任何进展。当前使用的用于辐射衰减或孢子菌冷冻保存的方法不适合生产用于人类使用的疫苗。在冷冻后，将辐照剂量的辐照剂量的最佳时间点是，但是没有关于这种冷冻保存方法的数据。在该项目中，将优化辐射衰减过程的所有方面，包括辐射的来源，辐射量，辐射时间长度，进行辐射的容器以及辐射暴露（dosimetry）的记录，以建立CGMP过程的基础。此外，将进行研究以确定感染蚊子的辐射，新鲜解剖的孢子岩或冷冻的孢子菌是否提供了最佳的免疫原 - 从疫苗生产的角度来看，后者是优选的。此外，将优化冷冻保存和解冻方法，以确保疫苗至少稳定至少6个月。目的是提供一种定义的方法，以产生优化的免疫原，该免疫原包含辐射稳定/冷冻保存的恶性疟原虫孢子岩，符合所有调节标准。该项目还将提供一种冷冻培训未脱落的子孢子的方法，该方法可用于通过在全球疫苗研究中向恶性疟原虫注射来挑战志愿者。