A letter from Meissa’s cofounder and CEO, Dr. Marty Moore.
Meissa was founded with the vision to develop a pediatric vaccine for respiratory syncytial virus (RSV). Identified in the 1950s, RSV remains a major cause of lower respiratory tract disease for infants, young children, and older adults, despite attempts with other vaccine technologies.
Live attenuated viral vaccines use a weakened (attenuated) form of the virus that causes disease, tend to be highly effective because they mimic natural infection, and given by the natural route of infection can be particularly effective. Our live attenuated vaccines are given intranasally, not by injection, and they are designed to induce immunity in the nose and upper respiratory tract in addition to protecting the lung.
However, sometimes natural infection is just not good enough. Some viruses that cause disease, like RSV, do not provide adequate natural immunity, so reinfection can occur later. RSV, like many other viruses, expresses genes that actively inhibit the immune response. Simply attenuating the growth of a virus like RSV and leaving its immune-inhibiting genes intact is not likely to result in an effective vaccine candidate.
Meissa takes advantage of years of research conducted in my lab at Emory University. During this time, we developed a live attenuated RSV vaccine candidate specifically designed to be attenuated and to not inhibit the immune response. This knowledge and technology are incorporated in Meissa’s AttenuBlock platform.
The rapid emergence of SARS-CoV-2 and the resultant societal disruption caused by the COVID-19 pandemic clearly underscore the need for technologies that can deliver effective vaccines that can not only prevent disease but also infection. While injected vaccines composed of DNA, RNA, or protein antigens can be rapidly generated and have the potential to protect against severe disease, they are not fundamentally designed to prevent infection. The potential to prevent viral transmission is a key advantage that intranasal vaccines have versus injected vaccines.
We knew we had to mobilize our team and the AttenuBlock platform against SARS-CoV-2. When we made that decision, we had preclinical data showing our RSV live attenuated vaccine candidate induces a strong immune response and protection against RSV. Shortly thereafter, clinical data showed it was safe, well-tolerated, and immunogenic in healthy adults. With these data to support our platform and approach, we officially launched our COVID-19 vaccine program. We continue to advance our RSV vaccine candidate in clinical trials as the company’s lead program.
Meissa’s COVID-19 vaccine candidate is a version of the RSV live attenuated candidate that shuttles the SARS-CoV-2 Spike gene, replacing the analogous gene in RSV. We think this approach can provide robust and durable immunity and be an economical and effective solution to control the burden and spread of COVID-19. Our candidate is designed for needle-free intranasal administration in a single adjuvant-free dose with a manufacturing process capable of supplying global demands. Clinical trials of our COVID-19 vaccine candidate are expected to begin in early 2021.
I am also exceptionally proud of the team and culture at Meissa. Roderick Tang and I have recruited determined virologists and vaccinologists who are driven to rid the world of viral scourges. We are fortunate to have a breadth of experienced team members dedicated to our cause. We approach each day with a science first mindset that drives our programs and mission forward.