It has been almost 7 months since the last update of our work on the COVID-19 vaccine candidate. In this post, we share the results and what we have learned. Because there are several other vaccines available that are highly effective against SARS-CoV-2, we decided to stop further research on our vaccine and to focus on developing cancer therapies. We will explain more about our decision in this post.
First, a brief reminder on why we decided to make a vaccine for SARS-CoV-2. Back in March, we started to get really worried about the impact of the spread of the virus on society and the potential lives it would take. We believed that with our technology, we would be able to help. We were optimistic that we could design and produce a vaccine very quickly, and we hoped to collaborate and partner with others for testing and bringing it to market.
Using our platform, Chad (our CSO) set to work and made several designs in less than a day. DNA fragments were ordered and synthesized, which we then assembled together. Taken together, we were able to design and build functional virus particles in less than a month. At the time, we were super thrilled about how fast we pulled this off. We went on to evaluate the vaccine and confirm that it works as predicted. We have shared how our vaccine candidate works in an earlier post. In short, we use a virus that’s been shown to be safe called vesicular stomatitis virus (VSV) and swap out the natural glycoprotein for the spike protein of SARS-CoV-2.
Now came the next several steps that we needed to take in parallel. First and foremost, we needed to find a lab with access to an animal facility that was willing to help us test our vaccine. We also needed to start manufacturing the vaccine in large quantities to enable the animal studies. Last, we needed to reach out to the FDA and start discussions about clinical trials. All of these steps were a first for us. All of them had unique challenges. Fortunately, the knowledge and skills gained from these experiences are highly translatable and can be used for our cancer research too.
We found a lab in the Scott Ritchey Research Center at Auburn University College of Veterinary Medicine that was willing to help us with testing our vaccine in rats. Our primary aim was to demonstrate safety, we evaluated the rats for any reactions to the vaccine and monitored them for a couple weeks for any negative side effects. A secondary aim was to determine whether antibodies were produced or not, an indication of immunization and potential protection from SARS-CoV-2.
In preparation for the study, we needed to manufacture “large” quantities of the virus. Compared to what we were used to, we needed to produce 100-1000x more. Producing multiple doses of pure, highly concentrated vaccines with minimal equipment was a big challenge. However, we pulled it off and rushed the vaccine to the airport, where some kind volunteer pilots flew it to Auburn to begin testing immediately.
Meanwhile, we looked to begin regulatory operations and contact the FDA. With the help of a few friends and highly experienced people, we initiated communication and determined next steps. We then wrote and submitted our first pre-IND document.
After several weeks of testing, we completed the study in early September. The rats tolerated the injection well, and there were no negative reactions to the vaccine; Clinical pathology ran a complete blood count (CBC) and chemistry to confirm. The rats also showed no signs of adverse effects in the weeks after vaccination. To the best of our team and collaborators’ knowledge, our vaccine seems safe. Great!
Next, could we also show immunogenicity? Unfortunately, no. Why? Our study did not have enough rats to collect enough blood to show immunogenicity. Since diagnostic tests for rats were not available, we had to adapt human assays, which complicated matters. This means that the sensitivity suffered, making things even more difficult. If we want to find out, we have to conduct a larger study.
After we started our rat study, it became increasingly clear that several vaccines were going to be ready by the end of year with very promising results. Also, we tried, but nobody was interested in partnering with us. Taken together, this led us to decide to not do another rat study and dedicate all our focus on our cancer research again.
Does our vaccine work? We do not know. It’s possible. We confirmed the vaccine had the spike protein, and that it binds the ACE2 receptor, like the natural virus. We have shown it is safe. In conclusion, this project was a success. With absolutely minimal resources we completed this project in 5 months, which is a great accomplishment. We learned a ton: from manufacturing large quantities of viral particles, to filtration and purification, to communicating with the FDA.
We are happy that Pfizer and Moderna received emergency authorization in the US, and that others are not far behind.
We are focused on cancer research again, and we look forward to sharing some exciting updates soon.