May 6, 2022

SQZ Biotechnologies to Host Live & Virtual R&D Investor Event on May 19, 2022 WATERTOWN, Mass.--(BUSINESS WIRE)-- SQZ Biotechnologies (NYSE: SQZ), focused on unlocking the full potential of cell therapies for multiple therapeutic areas, today announced that the company will host a live R&D investor event with optional virtual participation on Thursday, May 19, 2022, from 4:05 - 5:30 p.m. ET. The event will feature presentations on the company’s point-of-care (POC) manufacturing system, currently in internal testing, and its potential impact on cell therapy development. The company will also discuss its first anticipated clinical use in the SQZ® TAC clinical development program for celiac disease, which has an FDA investigational new drug application submission planned for the first half of 2023. Company leadership will also discuss the collaboration with STEMCELL Technologies and the development of a research-use-only Cell Squeeze® system. The event will include a special fireside chat on the present and future state of cell engineering. Speakers include: Robert S. Langer, Sc.D., Scientific Advisory Board Member and Founder of SQZ Biotechnologies, and David H. Koch Institute Professor at the Massachusetts Institute of Technology Klavs F. Jensen, Ph.D., Board Member and Founder of SQZ Biotechnologies, and Warren K. Lewis Professor of Chemical Engineering at the Massachusetts Institute of Technology Armon Sharei, Ph.D., Chief Executive Officer and Founder of SQZ Biotechnologies Moderated by Mike Huckman, Global Practice Leader, Executive Communications at Real Chemistry, and former CNBC Pharmaceuticals Reporter Event Details The company will host a live R&D Investor event with optional virtual participation on Thursday, May 19, 2022, beginning at 4:05 p.m. ET. Onsite and virtual participants can register in advance by completing the registration form on the event website: https://investorday.sqzbiotech.com/ . Following the event, a webcast replay will be made available on the company’s investor website: investors.sqzbiotech.com . About SQZ Biotechnologies SQZ Biotechnologies Company is a clinical-stage biotechnology company focused on unlocking the full potential of cell therapies for patients around the world and has active programs in oncology, autoimmune and infectious diseases, as well as additional exploratory initiatives to support future pipeline growth. The company’s proprietary Cell Squeeze® technology offers the unique ability to deliver multiple biological materials into many cell types to engineer what we believe can be a broad range of potential therapeutics. With demonstrated production timelines under 24 hours and the opportunity to eliminate preconditioning and lengthy hospital stays, our approach could significantly broaden the therapeutic range and accessibility of cell therapies. The company’s first therapeutic applications seek to generate target-specific immune responses, both in activation for the treatment of solid tumors and infectious diseases, and in immune tolerance for the treatment of autoimmune diseases. For more information, please visit www.sqzbiotech.com . Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation statements relating to events and presentations, our platform development, product candidates, preclinical and clinical activities, progress and outcomes, development plans, manufacturing capabilities, clinical safety and efficacy results, therapeutic potential, collaborations and market opportunities. These forward-looking statements are based on management's current expectations. Actual results could differ from those projected in any forward-looking statements due to several risk factors. Such factors include, among others, risks and uncertainties related to our limited operating history; our significant losses incurred since inception and expectation to incur significant additional losses for the foreseeable future; the development of our initial product candidates, upon which our business is highly dependent; the impact of the COVID-19 pandemic on our operations and clinical activities; our need for additional funding and our cash runway; the lengthy, expensive, and uncertain process of clinical drug development, including uncertain outcomes of clinical trials and potential delays in regulatory approval; our ability to maintain our relationships with our third party vendors and strategic collaborators; and protection of our proprietary technology, intellectual property portfolio and the confidentiality of our trade secrets. These and other important factors discussed under the caption "Risk Factors" in our most recent Annual Report on Form 10-K and other filings with the U.S. Securities and Exchange Commission could cause actual results to differ materially from those indicated by the forward-looking statements. Any forward-looking statements represent management's estimates as of this date and we undertake no duty to update these forward-looking statements, whether as a result of new information, the occurrence of current events, or otherwise, unless required by law. Certain information contained in this press release relates to or is based on studies, publications, surveys and other data obtained from third-party sources and our own internal estimates and research. While we believe these third-party sources to be reliable as of the date of this press release, we have not independently verified, and we make no representation as to the adequacy, fairness, accuracy or completeness of any information obtained from third-party sources. Contacts