Pandemic to an Epidemic
As the SARS-CoV-2 virus has spread around the world, it has developed mutations that result in new variants of the virus. These variations are concentrated in the so-called “Spike” protein used by the virus to gain entry to the body’s cells. This tendency has the potential to allow the virus to remain in long-term circulation in humans around the world. The spike also is the protein that is the target of the antibodies generated by current COVID-19 vaccines; so as variants arise, the effectiveness of these vaccines can be reduced.
To deal with the long-term, endemic presence of the virus, ImmunityBio is developing a universal booster vaccine candidate that targets both the spike protein and the nucleocapsid protein that coats the virus – and which has little variation. This approach has the potential to provide enhanced protection against current and future SARS-CoV-2 variants. Several peer-reviewed studies demonstrate that patients who have recovered from SARS-CoV in the 2003 outbreak possess long lasting memory T cells reactive to the nucleocapsid protein of SARS-CoV 17 years after infection. While antibodies block infection when present, T cells are vital for long-term immune memory.
While antibodies block infection when present, T cells are vital for long-term immune memory.
Our vaccine candidate does not require the difficult storage conditions of several current vaccines, making it more practical to make, store and distribute to remote areas. Its potential to be more resilient than current vaccines also means that fewer doses would be required to provider longer-term immunity, further reducing the complications and costs that now prevent much of the world from being vaccinated.
About Our COVID-19 Studies
ImmunityBio is addressing the serious need for a boost vaccine by conducting five COVID-19-related studies, three in South Africa and two in the U.S. The Phase 2 South Africa Sisonke T-Cell Universal Boost trial is, to our knowledge, the first randomized control trial to study a heterologous boost of an S-only vaccine with an Ad5 S+N vaccine boost versus a single S-only prime vaccine as control. The endpoints of the trial are to examine whether the boost could reduce breakthrough infections currently occurring in South Africa at a rapid rate.
About ImmunityBio’s hAd5 T-Cell-Based, Viral-Vector Vaccine Candidate
This second-generation hAd5 viral-vector vaccine is unique in targeting both S and N SARS-CoV-2 proteins to generate B and T cell memory to these antigens and, potentially, long-term immunity to the virus. Most of the COVID-19 vaccines approved by the FDA or in late-stage clinical trials deliver only the S protein which, by some estimates, has already mutated thousands of times.
Another unique characteristic of the hAd5 design is its use of a second-generation hAd5 platform that was developed to elicit anti-SARS-CoV-2 immune responses even in Ad-immune individuals, meaning subjects can receive the vaccine multiple times, if necessary. The stimulation of anti-hAd5 immune responses is attenuated with the second-generation platform in comparison with the first-generation platforms due to additional genetic deletions.
Finally, ImmunityBio’s novel hAd5 vaccine candidate has been developed in four formulations for different routes of administration: SC injection, SL drops, intranasal spray, and a room-temperature-stable oral capsule that could potentially overcome the cold-chain distribution hurdles affecting many current COVID-19 vaccines.
We believe that the key to creating long-term immunity to the SARS-CoV-2 virus and overcoming the variants that are rapidly developing around the world is to design a vaccine that activates not only antibodies but also memory B and T cells to multiple antigens. Furthermore, room temperature-stable formulations for oral delivery have the potential to solve the cold-chain challenges of distribution, and the ability to generate mucosal IgA antibody barriers to the virus in the upper respiratory tract where it first enters the body.