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.

抽象的 2020 年，疟疾导致 2.41 亿次临床发作和 627,000 人死亡，较 2019 年大幅增加。 非洲死于疟疾的人数多于死于 COVID-19 的人数 迫切需要满足未满足的医疗需求。 疟疾疫苗可预防个人感染和疾病，并可用于大规模疫苗接种 消除疟疾计划 基于超过 500,000 名婴儿的试点实施计划的结果， RTS,S/AS01 于 2021 年底被 WHO 推荐用于 5 个月婴儿免疫接种 4 次 实施 21 个月以来，RTS,S 使因疟疾和重症住院的人数显着减少了 21%。 它并没有显着降低脑型疟疾、严重疟疾贫血或总体死亡率，或 预防恶性疟原虫 (Pf) 感染的疫苗中，只有 Sanaria 的 PfSPZ 疫苗。 具有抗 Pf 感染的功效，可考虑用于预防个人 Pf 感染或用于预防 Pf 感染 Sanaria 的第一代疫苗 PfSPZ 疫苗是针对不同地区的 Pf 疟疾消除活动。 由辐射减弱的恶性疟原虫 (Pf) 子孢子 (SPZ) 组成，在肝脏早期停滞 3 期临床试验将于 2022 年中期开始，并在欧洲 (EMA) 和美国获得上市许可。 (FDA) 计划于 2023/2024 年推出 Sanaria 的第二代疫苗 PfSPZ-CVac（化学预防）。 在 PfSPZ-CVac 中，寄生虫在肝脏中复制，从而在生物上放大免疫原负荷。 50,000 倍，然后被与氯喹共同施用的抗疟疾药物杀死。 (CQ)，针对异源受控人类疟疾感染 (CHMI) 提供 100% 疫苗效力 (VE) 12 接种疫苗后几周，使用 22% 剂量的 PfSPZ 达到针对异源 CHMI 的 VE 80% 使用 PfSPZ 疫苗时，PfSPZ-CVac (CQ) 比 PfSPZ 疫苗的保护性更强，剂量约为 1/5。 第一次服用 PfSPZ 后可能会出现短暂的疟疾症状，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，以保留 PfSPZ- 的增强效力。 CVac 并消除其缺点，我们对 Pf 进行了基因改造，使其能够完全复制，但在 通过删除单个基因进入血液。 名为 PfSPZ-LARC1 的寄生虫在具有人源化肝脏的小鼠和人类体内完全减毒。 为了提高 PfSPZ-LARC 疫苗的潜在安全性，我们创建了一种删除了两个基因的寄生虫，PfSPZ- LARC2 也在肝脏后期停滞，Sanaria 也实现了 PfSPZ 的体外生产， 被称为 iPfSPZ，消除了生产 PfSPZ 疫苗时对蚊子的需求， 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、冷冻保存的 iPfSPZ- LARC2 并证明这些 iPfSPZ-LARC2 具有传染性，并且可以发展到肝脏晚期，但 在下一阶段，我们将生产 iPfSPZ-LARC2 用于临床试验评估。