Gritstone Announces Three Presentations for Tumor-Specific Neoantigen (TSNA) Oncology Programs, GRANITE and SLATE, at the 2022 AACR Annual Meeting

            — Oral presentation to discuss how translational immunology data enabled iterative development of an optimized, KRAS-specific version of “off-the shelf” vaccine candidate; the optimized version is now in Phase 2 testing for solid tumor patients — EMERYVILLE, Calif., March 08, 2022 (GLOBE NEWSWIRE) — Gritstone bio, Inc. (Nasdaq: GRTS), a clinical-stage biotechnology company developing next generation cancer and infectious disease immunotherapies, today announced three abstracts have been accepted for presentation at the upcoming American Association for Cancer Research (AACR) Annual Meeting 2022, taking place April 8-13, 2022, in New Orleans, Louisiana. In the poster presentations, Gritstone representatives will review data from individualized neoantigen program, GRANITE, and the “off-the-shelf” neoantigen vaccine program, SLATE. In the oral presentation, Christine D Palmer, PhD will discuss how immunodominant human T cell responses to tumor specific neoantigens presented by the same HLA in a first-generation construct informed development of a second-generation candidate that exhibits immunogenic superiority over version 1 in preclinical models within SLATE. This optimized candidate, SLATE-KRAS, exclusively includes KRASmut epitopes and is now in Phase 2 testing in solid tumor patients. Abstracts associated with these presentations are now available on the conference website. Details of the presentations are as follows: Oral Presentation Details Abstract 3578: Optimization of shared neoantigen vaccine design to increase vaccine potency: From bench to bedside and backDate/Time: Tuesday Apr 12, 2022, 2:30 PM – 4:30 PM ET Session: Clinical Research Excluding Trials; Resistance Mechanisms & New Advances in ImmunotherapeuticsPresenter: Christine D Palmer, PhDLocation: New Orleans Convention Center, Theater B Poster Presentation Details Abstract 4149: Lower doses of self-amplifying mRNA drive superior neoantigen-specific CD8+ T cell responses in cancer patients versus high doses Date/Time: Wednesday Apr 13, 2022, 9:00 AM – 12:30 PM ET Session: Clinical Research Excluding Trials; Vaccines/Immunomodulatory Agents & Interventions Presenter: Amy Rappaport, PhD Location: New Orleans Convention Center, Exhibit Halls D-H, Poster Section 34, Poster Board 13 Abstract 1238: Comprehensive ctDNA monitoring provides early signal of clinical benefit with a novel personalized neoantigen directed immunotherapy for late-stage cancer patients Date/Time: Monday Apr 11, 2022, 9:00 AM – 12:30 PM ET Session: Clinical Research Excluding Trials; Biomarkers Predictive of Therapeutic Benefit 1 Presenter: Matthew Davis, PhD Location: New Orleans Convention Center, Exhibit Halls D-H, Poster Section 30, Poster Board 10 About Gritstone Gritstone bio, Inc. (Nasdaq: GRTS), a clinical-stage biotechnology company, is developing the next generation of immunotherapies against multiple cancer types and infectious diseases. Gritstone develops its products by leveraging two key pillars—first, a proprietary machine learning-based platform, Gritstone EDGE™, which is designed to predict antigens that are presented on the surface of cells, such as tumor or virally-infected cells, that can be seen by the immune system; and, second, the ability to develop and manufacture potent immunotherapies utilizing these antigens to potentially drive the patient’s immune system to specifically attack and destroy disease-causing cells. The company’s lead oncology programs include an individualized neoantigen-based immunotherapy, GRANITE, and an “off-the-shelf” shared neoantigen-based immunotherapy, SLATE, which are being evaluated in clinical studies. Within its infectious disease pipeline, Gritstone is advancing CORAL, a COVID-19 program to develop a second-generation vaccine, with support from departments within the National Institutes of Health (NIH), the Bill & Melinda Gates Foundation, the Coalition for Epidemic Preparedness Innovations (CEPI) and through a license agreement with La Jolla Institute for Immunology. Additionally, the company has a global collaboration for the development of a therapeutic HIV vaccine with Gilead Sciences. For more information, please visit www.gritstonebio.com. Gritstone Forward-Looking StatementsThis 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 November 3, 2021 and any current and periodic reports filed with the Securities and Exchange Commission. Gritstone ContactsInvestors:George E. MacDougallDirector, Investor Relations & Corporate CommunicationsGritstone [email protected] Media:Dan Budwick1AB(973) [email protected]