Development of vaccination strategies for emerging pathogens are particularly challenging because of the sudden nature of their emergence and the long process needed for traditional vaccine development. Therefore, there is a need for development of a rapid method of vaccine development that can respond to emerging pathogens in a short time frame.
US-based biotechnology company Novavax has begun testing its new coronavirus vaccine candidates in animal models. The company constructed several vaccine candidates against Covid-19. The company expects that findings from the preclinical testing will help determine an optimal candidate for human studies, with a clinical trial anticipated to begin in May or June.
Novavax’s candidates are based on its recombinant protein nanoparticle technology platform to produce antigens obtained from the coronavirus spike (S) protein.
To boost immune responses, the company plans to leverage its Matrix-M adjuvant with the vaccine candidate.
While adjuvants based on novel, poorly charaterized substances have been hampered by safety concerns and limited efficacy, Matrix™ adjuvants stimulate strong antibody and cell-mediated immune responses induced by low antigen doses, long-duration immune responses, and carry a low risk for allergic reactions or other adverse events.
The Matrix™ technology typically induces strong cellular activation of both Th1 and Th2 types, thereby generating all classes and subclasses of antibodies, as well as potent cellular responses, including cytotoxic T lymphocytes.
The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV) in 2003 and Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in late 2012 demonstrate the importance of coronaviruses as emerging pathogens. The spike glycoproteins of coronaviruses reside on the surface of the virion and are responsible for virus entry. The spike glycoprotein is the major immunodominant antigen of coronaviruses and has proven to be an excellent target for vaccine designs that seek to block coronavirus entry and promote antibody targeting of infected cells.
Novavax president and CEO Stanley Erck said: “Our previous experience working with other coronaviruses, including both MERS and SARS, allowed us to mobilise quickly against COVID-19 and successfully complete the critical preliminary steps to engineer viable vaccine candidates.
“Now that the protein has been expressed stably in our baculovirus system, we aim to identify the optimal candidate and scale up production of sufficient vaccine for preliminary clinical trials.”
Last month, the company announced plans to use its recombinant nanoparticle technology to develop a Covid-19 vaccine candidate.
Novavax previously developed MERS and SARS vaccines, said to have shown encouraging immunogenicity and complete protection in preclinical testing.
Furthermore, the company created a clinically immunogenetic Ebola vaccine candidate, which demonstrated effectiveness in primate studies.