Gritstone Announces Results from Preclinical Study of its Self-amplifying mRNA (samRNA) Vaccine Against SARS-CoV-2 Published in Nature Communications
-- Results, which were previously pre-printed in bioRxiv, show Gritstone’s second-generation self-amplifying mRNA (samRNA) vaccine candidate drove broad neutralizing antibodies, T cell responses and offered protection against SARS-CoV-2 infection in rhesus macaques --
-- Neutralizing antibody responses were induced at up to a 10-fold lower dose than first-generation mRNA vaccines --
-- Durable protection against SARS-CoV-2 in rhesus macaques observed with the samRNA vaccine regimen supports ongoing therapeutic exploration in coronaviruses and other infectious diseases --
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Gritstone is currently evaluating four distinct SARS-CoV-2 product candidates across three different Phase 1 clinical trials containing various Spike variants plus additional highly conserved non-Spike T cell epitope sequences (and also full-length nucleocapsid) within its CORAL program. These studies include homologous and heterologous prime-boost regimens. All three of these studies are ongoing, and data from all are expected during the second half of 2022.
About Self-amplifying mRNA (samRNA)
Gritstone’s samRNA vector is based on a synthetic RNA molecule derived from a wild-type Venezuelan Equine Encephalitis Virus (VEEV) replicon with the goal of extending the duration and magnitude of immunogen expression to drive potent and durable immune responses. The samRNA is delivered in a lipid nanoparticle (LNP) formulation. Like traditional mRNA vaccines, samRNA vaccines use the host cell’s transcription system to produce target antigens to stimulate adaptive immunity. Unlike traditional mRNA, samRNA has an inherent ability to replicate by creating copies of the original strand of RNA once it is in the cell. Potential benefits of samRNA may include extended duration and magnitude of antigen expression, strong and durable induction of neutralizing antibody and T cell immunity (CD4+ and CD8+), dose sparing, and a refrigerator stable product.
About the CORAL Program
Gritstone’s CORAL program is a second-generation SARS-CoV-2 vaccine platform delivering spike and additional SARS-CoV-2 T cell epitopes, offering the potential for more durable protection and broader immunity against SARS-CoV-2 variants. Delivery vectors can comprise a chimpanzee adenovirus, self-amplifying mRNA (samRNA) or both. The program is supported by several key relationships:
Gritstone Forward-Looking Statements
This press release contains forward-looking statements, including, but not limited to, statements related to the potential of Gritstone’s therapeutic programs; the advancements in the company’s ongoing clinical trials; the timing of data announcements related to ongoing clinical trials and the initiation of future clinical trials. Such forward-looking statements involve substantial risks and uncertainties that could cause Gritstone’s research and clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, the uncertainties inherent in the drug development process, including Gritstone’s programs’ early stage of development, the process of designing and conducting preclinical and clinical trials, the regulatory approval processes, the timing of regulatory filings, the challenges associated with manufacturing drug products, Gritstone’s ability to successfully establish, protect and defend its intellectual property and other matters that could affect the sufficiency of existing cash to fund operations. Gritstone undertakes no obligation to update or revise any forward-looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward-looking statements, as well as risks relating to the business of the company in general, see Gritstone’s most recent Quarterly Report on Form 10-Q filed on
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