Sosei Heptares Announces Change of Market Listing Segment to the Tokyo Stock Exchange Prime Market

Tokyo, Japan and Cambridge, UK, 15 March 2023 – Sosei Group Corporation (“the Company”; TSE: 4565), the world leader in G protein-coupled receptor (GPCR) focused structure-based drug design (SBDD) and development, today announces it has changed the market on which the Company’s shares are listed on the Tokyo Stock Exchange, Inc. (“TSE”) from the Growth Market segment to the Prime Market segment, effective today. Chris Cargill, President & CEO of Sosei Heptares, commented: “We believe that this move to TSE Prime is a key milestone in our vision to become one of Japan’s leading global biopharmaceutical champions. We are confident that a Prime Market listing will improve our ability to attract diverse institutional investors who are familiar with this industry, hold a long-term perspective and can support the acceleration of our growth driven by our core strategy.” Rationale for the change The Company’s vision is to become one of Japan’s global biopharmaceutical champions, discovering, developing and commercializing life-changing medicines for patients worldwide based on its world-leading science and expertise. The Company expects the move to the Prime Market will help it to achieve its vision by providing enhanced support and access to the long-term capital through greater exposure to institutional investment funds, both domestic and international. This will result from a deepening and broadening of its shareholder base to reflect the global nature of the business. For more details regarding the change of Sosei Heptares’ listing to the Prime Market segment, please refer to the Japan Exchange Group’s website https://www.jpx.co.jp/english/ Core Strategic Priorities In its full year 2022 results presentation (held on 14 February 2023), Sosei Group’s leadership set out a clear strategy to leverage the Company’s proprietary platform, pipeline and R&D expertise to grow the business internationally and in Japan. This strategy has four key pillars: Extending and enhancing the competitive advantages of the Company’s world-leading StaR®/SBDD discovery capabilities; Diligently driving forward existing partnerships with global biopharma companies and initiating new high-value partnerships to ensure the continued flow of revenues;Transforming R&D to a program-centric operational model designed to enhance productivity, value and success; and Building out an agile, scalable and effective clinical development and commercialization business in Japan. 2023 Outlook In 2023, the Company expects to make progress against all four of its strategic priorities and will announce significant relevant updates in accordance with TSE regulations. Our objectives for each strategic priority are as follows. Invest to enhance GPCR SBDD platform capability; Execute at least one new high-value collaboration, and progress existing partnerships;Advance at least two new in-house programs into first-in-human clinical trials; and Take clear steps to build its Japan biopharma business (in-licensed or in-house products). -ENDS- About Sosei HeptaresWe are an international biopharmaceutical group focused on the discovery and early development of new medicines originating from our proprietary GPCR-targeted StaR® technology and structure-based drug design platform capabilities. We are advancing a broad and deep pipeline of novel medicines across multiple therapeutic areas, including neurology, immunology, gastroenterology, and inflammatory diseases. We have established partnerships with some of the world’s leading pharmaceutical companies and multiple emerging technology companies, including AbbVie, AstraZeneca, Genentech (Roche), GSK, Kallyope, Lilly, Neurocrine Biosciences, Novartis, Pfizer, Takeda and Verily. Sosei Heptares is headquartered in Tokyo, Japan with corporate and R&D facilities in Cambridge, UK. “Sosei Heptares” is the corporate brand and trademark of Sosei Group Corporation, which is listed on the Tokyo Stock Exchange (ticker: 4565). Sosei, Heptares, the logo and StaR® are trademarks of Sosei Group companies. For more information, please visit https://soseiheptares.com/LinkedIn: @soseiheptaresco | Twitter: @soseiheptaresco | YouTube: @soseiheptaresco Enquiries: Sosei Heptares – Media and Investor Relations Hironoshin Nomura, Chief Financial Officer Shinichiro Nishishita, VP Investor Relations, Head of Regulatory DisclosuresCandelle Chong, SVP Investor Relations and Corporate StrategyJapan: +81 (0)3 5210 3399 | United Kingdom: +44 (0)1223 949390 | [email protected] MEDiSTRAVA Consulting (for International Media)Mark Swallow, Frazer Hall, Eleanor Perkin+44 (0)203 928 6900 | [email protected] Forward-looking statementsThis press release contains forward-looking statements, including statements about the discovery, development, and commercialization of products. Various risks may cause Sosei Group Corporation’s actual results to differ materially from those expressed or implied by the forward-looking statements, including: adverse results in clinical development programs; failure to obtain patent protection for inventions; commercial limitations imposed by patents owned or controlled by third parties; dependence upon strategic alliance partners to develop and commercialize products and services; difficulties or delays in obtaining regulatory approvals to market products and services resulting from development efforts; the requirement for substantial funding to conduct research and development and to expand commercialization activities; and product initiatives by competitors. As a result of these factors, prospective investors are cautioned not to rely on any forward-looking statements. We disclaim any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.