Optimization of Downstream Recovery and Stabilization of Drug Substance of an Intranasal Influenza Vaccine

Seasonal influenza virus infections are one of the most serious respiratory infections in man causing significant annual hospitalizations, loss of life and productivity in the U.S. and the rest of the world. Licensed influenza vaccines are only moderately effective (50%-60%) and need to be matched annually to the strains currently circulating (drifted viruses). They are much less effective during years in which the vaccines are not matched to the circulating viruses. In addition, in the last century there have been four antigenic shifts among circulating viruses (changing one HA subtype to another) each resulting in a global influenza pandemic. Current vaccines offer no protection against an emerging pandemic virus and it can take up to six months before a matched pandemic vaccine can be produced. This creates an incumbent need for universal influenza vaccines with a high level of protection (>90%) against circulating strains that also can protect against emerging pandemic virus. To overcome the limitations of currently available influenza vaccines, FluGen is developing a Quadrivalent M2SR flu vaccine that provides broad-spectrum immunity including neutralizing antibody, mucosal and cellular immune responses. The quadrivalent formulation contains two flu A strains (H1N1 and H3N2) and two flu B strains (Yamagata and Victoria lineages). The influenza A viruses are produced in M2VeroA helper cells and the influenza B viruses are produced in BM2Vero helper cells. M2SR is administered intranasally and confers protection against influenza by multiple immune mechanisms. In humans and animal models, serum antibodies, mucosal antibodies and influenza-specific T cells have been elicited following M2SR immunization. We have successfully demonstrated proof-of-concept drift protection and immunogenicity with monovalent M2SR in humans and drift protection with the Quadrivalent M2SR in animal models. These proposed studies address the FY23 PRMRP portfolio Respiratory Health; topic area Respiratory Health; and strategic goal Prevention. The overall objective of this project is to further develop the M2SR universal influenza vaccine platform and understand its performance compared to licensed vaccines. The overall objective of this project is to further develop the M2SR universal influenza vaccine and its production platform. Building upon the successful development of upstream and downstream purification processes at the 10L scale, in this proposal we plan to optimize the downstream process for recovery of the live virus during purification from host cell debris and evaluate excipients to stabilize the four purified viruses in a refrigerator (2-8ºC) stable quadrivalent formulation. In addition, we will manufacture each of the monovalent components of the Quadrivalent M2SR in engineering runs and use the material in an IND-enabling GLP toxicology study. The objectives of this application are to: 1. Optimize recovery of live M2SR virus in the downstream process 2. Develop a bulk drug formulation for 2-8ºC storage of the blended drug product 3. Manufacture of engineering batches at 10L scale for Quadrivalent M2SR. 4. Conduct an IND-enabling GLP toxicology study with Quadrivalent M2SR in ferrets The development of a broadly reactive influenza vaccine like M2SR will reduce influenza morbidity and mortality. This will have a significant public health and military impact. Influenza infections among military personnel are known to impact DOD readiness here and abroad. Vaccination with a universal M2SR vaccine would help maintain military readiness by protecting military personnel from both seasonal and pandemic strains. Finally, influenza complications are a leading cause of morbidity and mortality in older adults, like retired military Veterans. A more effective vaccine with broader coverage could provide substantial benefits for the retired military population served by the VA as well. Less