Mark Newman
Analyst · Maxim Group. Please go
Thank you, David. Let me start with a general slide here to point out that immune responses against viral infections are characterized by both antibodies and cell-based effector mechanisms. The antibodies are specific for virus surface proteins, and their function is to block the virus from infecting the cell. This is referred to as virus neutralization. You've probably heard the term in the news. These can also limit not only the initial infection, but the spread from one cell to another within the body and localize the infection. Now, the first generation COVID vaccines were designed primarily to induce antibodies. They're specific to the S Protein, the Surface Protein of COVID, and their effectiveness is typically measured and reported as a function of virus neutralization, and a natural virus infection, cellular immune responses are also important. These responses are characterized as the activity of T lymphocytes, also referred to as T-cells. These cells directly limit virus replication in the body. They also contribute to the clearance of viral infection in the body by actually killing virus infected cells. For a vaccine to really be optimally effective, needs to induce both antibodies and T-cells. And that needs to function in a coordinated manner. We need to induce a subpopulation of cells, both antibodies and T-cells that will remain in the body for a long period of time and refer to as memory cells. Memory cells are important because these are the cells that are capable of responding rapidly at subsequent infections. So, the COVID virus, next slide presents a very challenging situation for vaccines. This is because mutations can accumulate within the virus, they change the structures of the proteins. These will lead to variants that are not recognized by existing immune responses. And then if you get a variant that is not recognized by a pre-existing antibody induced response, then these will be referred to as an escape mutant. And I'm sure you've all heard of this type of thing in the general press. Just on this graphic on the right here, I want to show you, this is the variation that has been tracked within a population of COVID variants with just over a year. So, it's a highly variable virus within the population. And this started from a single type of virus. The next slide shows you the – next slide shows you the concern that the World Health Organization puts on this. There are multiple mutations in the S protein, and these can lead to varying forms of virus that escaped immune responses that are induced by the first generation vaccines. Remember, first generation vaccines are based on the S Protein. S Protein, mutations not only impact the ability of the antibodies induced by the vaccine to neutralize the virus, but these mutations in the S Protein can actually impact the effectiveness of the virus to infect cells, and increases transmissibility. Today we’re witnessing the Delta strain or the Delta variant. This variant is as of today the most highly transmissible of the COVID strains yet studied. It's also somewhat resistant to the first generation antibodies that are induced – the antibodies that are induced against the – with the first generation vaccines. So, it's posing a real significant problem. Now, it's a major concern and if you look at this table it becomes quite obvious, the Delta variant is the fourth variant down, there's already four more variants that are labeled as COVID, COVID variants of concern by the World Health Organization. We don't yet know the risk of these. We also don't yet know the effectiveness of the current generation of vaccines to protect against them, but it's clear that we need to be doing something else. Now, the GeoVax program is also designed – is to design vaccines that will also induce the T-cell responses. Why target T-cell responses? Well, a study of T-cell responses has been completed by a number of labs using blood samples obtained from individuals that got COVID naturally, but recovered from the infections. So, this type of analysis can be used to document the importance of T-cells. What it shows is the T-cell responses specific to many proteins can be measured. This includes the S protein, but also other structural and non-structural proteins. CD4 T lymphocytes tend to predominate the response. This is a type of cell – a T-cell that can directly reduce virus replication, but it's also a type of T-cell that supports the development and maintenance of other immune system functions. This includes memory and active antibody production and CDA T-cells. These are the cells that are commonly referred to as killer T-cells, which mediates the clearance of virus from an infected individual. Importantly, the study severely infected patients has demonstrated that those that have a significantly better T-cell response are likely to do better, spend less time in a hospital, and recover more quickly. So, this is important in a vaccine setting, and can be tied back to the original SARS infections, which occurred back in 2003. Individuals that recovered from the SARS virus back in 2003 still have memory T-cell responses to the virus. So, the T-cells can be long lived, providing a long duration of response. This is critical because the induction of durable immunological memory is the goal of a successful vaccination. We believe this can be optimally achieved through the induction of the correct T-cell responses. Now, next slide shows you how to target the T-cell responses appropriately. The rise of variants in alterations is typically characterized based on variation in the S protein. You look at this figure here in this graph, what this shows you is that if we evaluate the genomes of multiple COVID variants and related viruses we see that there are proteins that are not variable. These are shown in this graphic as the ORF1a and ORF1b. These are proteins that are critical to basic coronavirus functions. If we get into the S protein, the surface protein or the spike protein, you can see that the variation increases dramatically. And this is shown as a decrease in the relatedness of the different viruses. What this tells you is that the virus is capable of changing the S protein leading to variations without destroying the virus's ability to replicate. Now, the proteins that are encoded by genes that are much more high they can serve are required for virus replication. And these become obvious targets for vaccine design, because the virus cannot allow for escape, cannot allow for variation in the generation of variants. The next slide shows you where we are in the GeoVax system. This is a slide that has been shown before so you might recognize it. Design of vaccines that induced immune responses specific for multiple COVID viral proteins has been the focus of the GeoVax effort. We can do this because our ability to work with the MVA viral vector. This is central to the GeoVax approach. The MVA vector allows us to produce vaccines that encode multiple viral gene proteins at the same time in a single vaccine construct, not in the mixture. On this graph, like this would be shown as the blue antigen, the orange antigen, and the green antigen. Now, our initial efforts are focused on MVA vectored vaccines that encode multiple forms of the S Protein, in combination with a membrane and the envelope proteins. So, this is SMNE. The expression of SMNE proteins together drives the formation of virus like particles within the cells of the body of the vaccinated animal. This is shown as the little satellite figures in this picture. The VLP structure is important because it presents the immune system with the vaccine proteins in a form that mimics a virus, but it's non-infectious. It looks authentic, it concentrates the vaccine proteins into a particle, but it's not infectious. So, we believe these properties the VLP will augment the potency and induce immune responses that are most relevant to inducing a protective response. The next slide just shows the lead candidate at this stage of the game. This is referred to as CMO2. What I'm showing you here is, we have a construct, it is stable, which is important because this means that we can produce it. This is showing in the left side. The virus like particle structure is shown in the lower left. These are actual virus like particles produced by the – who’s production is directed in the body by the MVA. They look like the SARS virus, but they are not. On the right side we are showing that we can or in fact can detect the expression of the S Protein, which of course will be the antibody target for using a pre-fusion stabilize conformation of the protein, which is the same S Protein has used in the first generation vaccines and is known to induce the best neutralizing antibodies. The VLP also contains the M and the E proteins, which is shown in the lower right side with different colored figures. This shows the expression in the cells that are infected with the MDA. These will be targets that are highly conserved and will generate T-cell responses, which is separate from the S Protein. On the final slide is, I want to point out that the results of the initial studies with small animals led to the selection of the CMO2 product, as well as the data that I've shown you here on the – in the lab characterization. The animal studies will be the basis of the – this vaccine will be the basis of the COVID – of the GeoVax universal COVID vaccine effort wherein we can add additional gene products to expand T-cell responses. These results will be presented in more detail in the European Society of Medicine Conference, which is to be held in approximately one week August 19 in Berlin. This MVA vector vaccine represents the first step towards a universal vaccine goal because it is designed to induce immune responses beyond the S Protein. We're including the highly conserved membrane protein as a T-cell target. Importantly, the CMO2 can be a scaffold, which is used to design and to produce experimental vaccines that will target additional proteins of the COVID virus, selecting those which are most highly conserved, to induce a broad T-cell response to work in concert with the antibody responses. The design and production of these next generation vaccine efforts is already the subjects of efforts that David mentioned, we're focused we have a larger grant proposal in with the FDA, and we'll be submitting a proposal for support with [Sepi]. Now, I'd like to turn the presentation over to Mark Reynolds.