In vitro bioreactor production of a genetically modified late liver stage-arresting replication competent Plasmodium falciparum sporozoite vaccine

体外生物反应器生产具有复制能力的转基因晚期肝阶段恶性疟原虫子孢子疫苗

• 批准号: 10547414
• 负责人: B. KIM LEE SIM
• 金额: $ 30万
• 依托单位: SANARIA, INC.
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-03 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10547414
• 关键词: Africa; Africa South of the Sahara; African; Antigens; Antimalarials; Area; Attenuated; Authorization documentation; Bioreactors; Bite; Blood; COVID-19; Cerebral Malaria; Cessation of life; Characteristics; Chemoprophylaxis; Child; Chloroquine; Clinical; Clinical Trials; Communities; Cryopreservation; Culicidae; Detection; Development; Disease; Dissection; Dose; Ensure; Erythrocytes; Europe; Falciparum Malaria; Female; Fiber; Generations; Genes; Geographic Locations; Geography; Goals; Harvest; Hepatocyte; Hospitalization; Human; Immunization; Immunization Programs; Immunize; In Vitro; Individual; Infant; Infection; Infection prevention; Licensure; Liver; Malaria; Malaria Vaccines; Marketing; Mass Vaccinations; Medical; Metabolic; Methods; Mus; Netherlands; Oocysts; Parasites; Pathology; Persons; Phase; Phase III Clinical Trials; Plasmodium falciparum; Plasmodium falciparum vaccine; Pregnant Women; Prevention; Procedures; Process; Production; Quality Control; Radiation; Safety; Salivary Glands; Sporozoite vaccine; Sporozoites; Symptoms; Vaccination; Vaccine Production; Vaccines; Vial device; base; cost; human model; humanized mouse; in vivo; malaria infection; malarial anemia; male; mortality; mouse model; next generation; prevent; programs; research clinical testing; tool; transmission process; vaccine efficacy

ABSTRACT In 2020 malaria caused 241M clinical episodes and 627,000 deaths, a significant increase from 2019. There were more deaths in Africa from malaria than from COVID-19. There is an urgent unmet medical need for a malaria vaccine that prevents infection and disease in individuals and can be deployed in mass vaccination programs for malaria elimination. Based on results of a pilot implementation program in >500,000 infants, RTS,S/AS01 was recommended in late 2021 by WHO for immunization of 5-month-olds with 4 immunizations administered over 21 months. RTS,S significantly reduced hospital admissions for malaria by 21% and severe malaria by 30%. It did not significantly reduce cerebral malaria, severe malaria anemia, or overall mortality, or prevent Plasmodium falciparum (Pf) infection. Of vaccines under development, only Sanaria’s PfSPZ vaccines have the efficacy against Pf infection to be considered for prevention of Pf infection in individuals or for geographically focused Pf malaria elimination campaigns. Sanaria’s 1st generation vaccine, PfSPZ Vaccine, is comprised of radiation-attenuated Plasmodium falciparum (Pf) sporozoites (SPZ), which arrest early in the liver stage. Phase 3 clinical trials will begin in mid 2022, and marketing authorizations in Europe (EMA) and the US (FDA) are planned for 2023/2024. Sanaria’s 2nd generation vaccine is PfSPZ-CVac (Chemoprophylaxis Vaccine). In PfSPZ-CVac, the parasites replicate in the liver, biologically amplifying the immunogen load by up to 50,000-fold and then are killed by an anti-malarial drug. PfSPZ-CVac co-administered with chloroquine (CQ), gave 100% vaccine efficacy (VE) against heterologous controlled human malaria infection (CHMI) 12 weeks after vaccination using 22% the dose of PfSPZ needed to achieve 80% VE against heterologous CHMI with PfSPZ Vaccine. PfSPZ-CVac (CQ) is more protective than PfSPZ Vaccine at ~1/5 the dose. However, transient symptoms of malaria can occur after 1st dose of PfSPZ, and if CQ is not administered appropriately, parasite multiplication in the blood could cause severe malaria. To retain the enhanced potency of PfSPZ- CVac and eliminate its drawbacks, we genetically altered Pf to be able to fully replicate, but arrest prior to entering the blood by deleting a single gene. The first of our late arresting replication competent (LARC) parasites called PfSPZ-LARC1, was completely attenuated in mice with humanized livers and in humans. To increase the potential safety of PfSPZ-LARC vaccines, we created a parasite with two genes deleted, PfSPZ- LARC2, which also arrests late in the liver stage. Sanaria has also achieved in vitro production of PfSPZ, referred to as iPfSPZ, thereby eliminating the need for mosquitoes in manufacturing PfSPZ vaccines and significantly increasing efficiency and decreasing costs of producing PfSPZ vaccines. In this project we will optimize in vitro production and purification of iPfSPZ-LARC2, produce aseptic, purified, cryopreserved iPfSPZ- LARC2 and demonstrate these iPfSPZ-LARC2 are infectious, and can develop into late liver stages but are attenuated. In the next phase, we will manufacture iPfSPZ-LARC2 for assessment in clinical trials.

摘要 2020年，疟疾导致2.41亿例临床发作和62.7万人死亡，比2019年大幅增加。那里 在非洲，死于疟疾的人数超过了死于新冠肺炎的人数。有一种迫切的、未得到满足的医疗需求 预防个人感染和疾病并可大规模接种的疟疾疫苗 消除疟疾的方案。根据一项针对500,000名婴儿的试点实施计划的结果， 2021年底，世界卫生组织推荐用RTS、S/AS01对5个月龄婴儿进行4次免疫接种 给药时间超过21个月。RTS，S因疟疾入院人数显著减少21%和严重 疟疾减少30%。它没有显著降低脑型疟疾、严重疟疾贫血或总死亡率，或者 预防恶性疟原虫(PF)感染。在开发中的疫苗中，只有Sanaria的PfSPZ疫苗 有没有预防个人感染肺炎支原体的疗效，或 以地理为重点的消除疟疾运动。Sanaria的第一代疫苗，PfSPZ疫苗，是 由辐射减毒的恶性疟原虫(PF)子孢子(SPZ)组成，它们在肝脏早期停止 舞台。第三阶段临床试验将于2022年年中开始，并在欧洲(EMA)和美国获得营销授权 (FDA)计划于2023/2024年举行。Sanaria的第二代疫苗是PfSPZ-CVac(化学预防 疫苗)。在PfSPZ-CVac中，寄生虫在肝脏中复制，在生物上放大免疫原负荷 到50,000倍，然后被抗疟疾药物杀死。PfSPZ-CVAc与氯喹联合给药 (CQ)，对异源控制的人类疟疾感染(CHMI)给予100%的疫苗效力(VE)12 接种后几周，使用22%的PfSPZ剂量，可达到对抗异种CHMI的80%VE 使用PfSPZ疫苗。PfSPZ-CVAc(CQ)在~1/5剂量时比PfSPZ疫苗具有更强的保护作用。然而， 在第一剂PfSPZ后会出现一过性疟疾症状，如果CQ给药不当， 寄生虫在血液中繁殖可能会导致严重的疟疾。为了保持PfSPZ的增强效力- CVAC消除了它的缺点，我们对PF进行了基因改造，使其能够完全复制，但在此之前就停止了 通过删除单个基因进入血液。我们的第一个迟捕复制能力(LARC) 被称为PfSPZ-LARC1的寄生虫在人源化肝脏的小鼠和人类身上完全减弱。至 为了增加PfSPZ-LARC疫苗的潜在安全性，我们创造了一种两个基因缺失的寄生虫，PfSPZ- LARC2，它也在肝脏阶段后期停滞。Sanaria还实现了PfSPZ的体外生产， 称为IPfSPZ，从而消除了生产PfSPZ疫苗时对蚊子的需求 显著提高生产PfSPZ疫苗的效率和降低成本。在这个项目中，我们将 优化IPfSPZ-LARC2的体外生产和纯化，生产无菌、纯化、低温保存的IPfSPZ- LARC2，并证明这些IPfSPZ-LARC2是传染性的，可以发展到肝脏晚期，但 衰减了。在下一阶段，我们将生产用于临床试验评估的IPfSPZ-LARC2。