Genetically Attenuated Malaria Attenuated Whole Parasite Sporozoite Vaccine

基因减毒疟疾全寄生虫子孢子疫苗

• 批准号: 8024544
• 负责人: STEPHEN Lev HOFFMAN
• 金额: $ 99.51万
• 依托单位: SANARIA, INC.
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8024544
• 关键词: Acyl Carrier Protein; Africa; Antibiotic Resistance; Antibiotics; Attenuated; Biological; Biological Assay; Bite; Blood; Cessation of life; Clinical Trials; Country; Culicidae; Cytosine deaminase; Deaminase; Development; Dihydrofolate Reductase; Engineering; Environment; Erythrocytes; Excision; Fatty Acids; Gene Deletion; Genes; Genetic; Genetic Engineering; Goals; Growth; Hand; Health Benefit; Hepatocyte; Human; Human Volunteers; Immunity; Impairment; In Vitro; Individual; Infection; Invaded; Knock-out; Lead; Licensure; Ligase; Literature; Liver; Malaria; Malaria Vaccines; Marketing; Mutation; Nature; Oxidoreductase; Parasites; Pathway interactions; Phase; Phase I Clinical Trials; Plasmodium berghei; Plasmodium falciparum; Positioning Attribute; Process; Production; Proteins; Public Health; Radiation; Reagent; Reporting; Research; Research Design; Research Methodology; Safety; Site; Sporozoite vaccine; Sporozoites; Staging; Sterility; Testing; Thioctic Acid; Thymidine Kinase; Thymidylate Synthase; Transfection; Transferase; Untranslated Regions; Up-Regulation; Uracil; Vaccine Production; Vaccines; Work; asexual; assay development; attenuation; base; blasticidin S; cell bank; clinical lot; commercialization; disease transmission; empowered; improved; irradiation; manufacturing process; novel; paralogous gene; phase 2 study; phase 3 study; pre-clinical; prevent; product development; prophylactic; protective efficacy; public health relevance; pyruvate dehydrogenase; tool; vaccine candidate; vaccine development

DESCRIPTION (provided by applicant): Malaria is responsible for hundreds of millions of cases and a million deaths annually. An ideal tool for eliminating Plasmodium falciparum (Pf), the causative agent of 99% of all malaria deaths, would be a highly effective vaccine that prevents blood stage infection and thereby prevents all disease and transmission. When radiation attenuated Pf sporozoites (Pf SPZ) are administered by bite of infected mosquitoes, > 90% of human volunteers are protected for at least 10 months against experimental Pf challenge. Sanaria's goal is to develop and commercialize an attenuated Pf SPZ vaccine that prevents Pf blood stage infection in > 90% of recipients. Such a vaccine has the potential for > $1 billion annual revenues in markets in the developed and developing world. Sanaria has succeeded in establishing robust, reproducible, and consistent manufacture and release of clinical lots of its radiation attenuated PfSPZ Vaccine, received FDA approval for its IND, and in the 2nd quarter of 2009 will initiate a Phase 1 clinical trial to assess safety and protective efficacy of the PfSPZ Vaccine. After demonstrating safety, the goal is to move rapidly to safety and proof of concept efficacy studies, expanded Phase 2 studies and Phase 3 studies in Africa to support licensure. There is a clear path to taking this PfSPZ Vaccine to registration and commercialization. However, a number of experts believe that it would be preferable if the SPZ were attenuated by permanent genetic alteration (i.e. gene deletions) rather than by irradiation. This elegant, defined approach has the potential to be safer and might give rise to more potent attenuated SPZ. For our Phase I project, the goal was to produce at least one genetically modified Pf knock out (KO) clone that produced Pf SPZ that could 1) invade human hepatocytes, 2) develop in hepatocytes and produce proteins not expressed in SPZ, and 3) not be able to fully mature in hepatocytes (i.e. be fully attenuated). Our collaborative work has led to production of two single KO clones (p52 and fabI) that fulfill the 1st two goals, one of which (p52) has already been shown to fulfill all three, and a double KO clone (lacking p52 and p36) that has yet to be characterized. The single KO clones were created by single site crossover disruption and all three retain a selectable marker. Herein, we propose a systematic approach that will lead to the production of at least one Pf parasite clone optimized for attenuation, safety, potency, and suitability for manufacture. This involves deleting selected pairs of genes, each resulting in liver stage attenuation, using a double crossover strategy. This approach will maximize the likelihood of sustained attenuation and safety. Removal of selectable markers will eliminate the chance of inducing antibiotic resistance in the host or the environment. Testing of multiple doubly attenuated KO clones will maximize the prospects of identifying one that is optimal for gametocyte and SPZ production, attenuation, and potency. Process development and an engineering production campaign will produce genetically attenuated SPZ that fulfill regulatory requirements and can be manufactured and then tested in humans as a candidate vaccine. PUBLIC HEALTH RELEVANCE: A highly effective malaria vaccine would have an enormous public health benefit. Sanaria's attenuated malaria sporozoite vaccine (PfSPZ Vaccine) is expected to be highly effective and will be studied in clinical trials in 2009. The PfSPZ Vaccine is attenuated (weakened) by irradiation of each vaccine lot. This research aims to eliminate the need for irradiation in manufacturing a PfSPZ vaccine, by creating parasites that are attenuated by gene removal.

描述（由申请人提供）：疟疾每年造成数亿例和一百万例死亡。消除恶性疟原虫（PF）的理想工具，是所有疟疾死亡的99％的致病药物，是一种高效的疫苗，可防止血液阶段感染，从而阻止所有疾病和传播。当被感染的蚊子咬伤时，当辐射减弱的PF孢子虫（PF SPZ）被施用时，> 90％的人类志愿者至少保护了10个月，以防止实验性PF挑战。 Sanaria的目标是开发和商业化衰减的PF SPZ疫苗，该疫苗可防止90％的受体中PF血液阶段感染。这种疫苗在发达国家和发展中国家的市场中有可能获得> 10亿美元的年收入。 Sanaria成功地建立了强大的，可重现的和一致的制造和释放其临床批次减毒的PFSPZ疫苗，获得了FDA的IND批准，并在2009年第二季度将启动1期临床试验，以评估PFSPZ疫苗的安全性和保护功效。在证明安全后，目标是迅速迈向概念效能研究的安全和证明，扩大了第2阶段的研究和非洲第三阶段研究以支持许可。采用这种PFSPZ疫苗进行注册和商业化有明确的途径。但是，许多专家认为，如果SPZ因永久遗传改变（即基因缺失）而不是通过辐射而减弱SPZ是可取的。这种优雅，定义的方法有可能更安全，并可能导致更有效的衰减SPZ。在我们的第一阶段项目中，目标是生产至少生成一种遗传修饰的PF敲除（KO）克隆，产生PF SPZ，可能1）侵袭人肝细胞，2）在肝细胞中发展并产生在SPZ中未表达的蛋白质和3），无法在Hepatococytes中完全成熟。我们的合作工作导致了实现第一个目标的两个单个KO克隆（P52和Fabi）的生产，其中一个（p52）已经证明可以满足这三个目标，而一个双重KO克隆（缺少P52和P36）尚未表征。单个KO克隆是通过单个站点交叉中断创建的，所有三个都保留了可选标记。在本文中，我们提出了一种系统的方法，该方法将导致至少生产一个PF寄生虫克隆，以优化用于衰减，安全性，效力和适合制造的PF寄生虫。这涉及删除选定的基因对，每个基因都使用双跨界策略导致肝阶段衰减。这种方法将最大程度地提高持续衰减和安全性的可能性。去除可选标记将消除在宿主或环境中诱导抗生素耐药性的机会。测试多个双重衰减的KO克隆将最大程度地识别出对配子细胞和SPZ产生，衰减和效力最佳的前景。过程开发和工程生产运动将产生遗传上的SPZ，以满足监管要求，可以在人类中作为候选疫苗进行制造然后进行测试。 公共卫生相关性：高效的疟疾疫苗将具有巨大的公共卫生益处。 Sanaria的疟疾孢子菌疫苗（PFSPZ疫苗）预计将非常有效，并将在2009年进行临床试验中进行研究。PFSPZ疫苗通过每个疫苗的照射减轻（减弱）。这项研究旨在通过产生因去除基因而减弱的寄生虫来消除生产PFSPZ疫苗的辐射的需求。