The ideal, most effective, tool for eliminating Plasmodium falciparum (Pf), the causative agent of 99% of all malaria deaths, is a highly effective vaccine that prevents blood stage infection and thereby prevents both disease and transmission. Sanaria's goal is to develop and commercialize a Pf sporozoite (SPZ) vaccine that prevents Pf blood stage infection in >90% of recipients. The Sanaria(R) PfSPZ Vaccine is composed of attenuated, purified, aseptic, cryopreserved PfSPZ. The platform technology developed to manufacture the vaccine has also facilitated the manufacture of PfSPZ for challenge infections to test vaccines and drugs (PfSPZ Challenge) and for vaccination by challenge under chemoprophylaxis (PfSPZ-CVac). These comprise a portfolio of products that are on an aggressive timeline to commercialization. Manufacture of all these PfSPZ products is dependent on Anopheles stephensi mosquitoes that can survive aseptic rearing from eggs to adults and produce high numbers (>105) of PfSPZ in their salivary glands. A vulnerable aspect of Sanaria's manufacturing process is its reliance on mosquitoes that can only be maintained in colonies; such colonies are susceptible to crashes and to genetic drift over time, thereby being at risk of permanently losing the desired genotype and phenotype. This is because despite decades of effort, until our breakthrough achievement in Phase I, live Anopheles could not be preserved in any way. In Phase I we demonstrated new enabling technology, the capability to cryopreserve eggs of A. stephensi (SDA500-9800 strain). In the GMP context, being able to cryopreserve large lots of eggs will allow Sanaria to inaugurate controlled manufacturing by use of a Master Mosquito Bank, thereby enabling us to return repeatedly to a repository stock generated from the same defined, characterized material with the desired genetic background. With careful management, such a stock can last for many tens of years. In this Phase II project we will fully optimize the cryopreservation method (Specific Aim 1), and use this method in scaled-up production, initially to ensure security of the colony for manufacturing purposes (Specific Aim 2) and subsequently for producing the larger Master Mosquito Egg Bank (Specific Aim 3) from which all mosquitoes used in manufacturing will be sourced. Details of the characterized Master Mosquito Egg Bank will be submitted to the FDA as a Biologics Master File. We will also systematically apply the egg cryopreservation technology to support development of improved strains of A. stephensi and to create banks of eggs of such strains when developed (Specific Aim 4). Success in this project will have a critically important impact on Sanaria's commercial success.
To protect individuals against malaria and to aid in eradicating this disease, a highly effective vaccine is needed. Sanaria has developed a platform technology, the manufacture of live Plasmodium falciparum sporozoites (PfSPZ) to make such a vaccine. Two are in clinical development. The first is a live attenuated whole organism vaccine called the PfSPZ Vaccine which is currently being tested in a clinical trial at the Vaccine Research Center at the National Institutes of Health. The second is a live infectious vaccine administered with an antimalarial drug, a vaccine called PfSPZ-CVac which will enter clinical trials later in 2012. In addition Sanaria has developed live, infectious PfSPZ, a product called PfSPZ Challenge, for use in testing malaria drugs and vaccines. This product is currently undergoing clinical trials to optimize dose and route of administration. All the products require the growth of PfSPZ in aseptic Anopheles stephensi mosquitoes. This proposal aims to preserve Sanaria's genetic stock of A. stephensi by optimizing methods for cryopreservation of mosquito embryos and scaling up the methods to allow rapid replacement of the mosquito colony and develop the first ever GMP Master Mosquito Bank. The proposal will also support the huge international effort to release genetically modified mosquitoes (GMM) for malaria control by providing enabling technologies critical for the preservation of novel GMM lines and for the necessary scale up of mosquito rearing.
