^Ad hoc announcement pursuant to Art. 53 LR Allschwil, Switzerland - July 20, 2023 Idorsia Ltd (SIX: IDIA) today announced the sale of its operating businesses in the Asia Pacific (ex-China) region ("Territory"), including assignment of PIVLAZ (clazosentan) and license rights to daridorexant in those territories, to Sosei Group Corporation (TSE: 4565; 'Sosei Heptares') for a total consideration of CHF 400 million. Jean-Paul Clozel, Chief Executive Officer of Idorsia, commented: "Dr Satoshi Tanaka and his team in Idorsia Japan have consistently demonstrated their ability to deliver high-quality clinical development studies, most recently reporting positive Phase 3 results with daridorexant. They also developed, registered, and successfully brought PIVLAZ to a specialty market, serving over 5'000 patients with a rare form of stroke in the first year alone. The excellence displayed by the organization has been recognized by Sosei, hence a deal that creates value for both companies. I'm particularly happy that we are maintaining our relationships to the team and our ability to reach patients in the territory with our pipeline products." Chris Cargill, President, and Chief Executive Officer of Sosei Heptares, commented: "We have patiently and diligently been searching for the right opportunity to accelerate our mission to deliver life-changing new medicines to patients. This transaction with Idorsia is truly transformational and achieves one of our key strategic objectives, establishing Sosei Heptares as a fully integrated Japan- focused pharmaceutical business, with growing commercial sales and an expected new product launch next year. The addition of a highly experienced clinical development and entrepreneurial commercial team in Japan led by Dr Satoshi Tanaka, one of the country's most successful drug developers in recent times, fast-tracks our vision to become one of Japan's global biopharmaceutical champions." About the transaction The transaction includes the acquisition by Sosei Heptares of Idorsia's affiliates in Japan and South Korea, the assignment of the license for PIVLAZ (clazosentan) and all intellectual property and know-how for the territory, and a co-exclusive license for daridorexant - further to the agreement in place with Mochida Pharmaceutical. The transaction also includes an option for Sosei Heptares - upon payment of separate option fees - to license cenerimod and lucerastat for the development and commercialization in the Territory. Idorsia will supply bulk tablet of PIVLAZ and daridorexant to Sosei Heptares. In addition, there will be transition service agreements (TSA) between Idorsia and Sosei Heptares mainly for regulatory/filing activities, clinical development, CMC (Chemistry, Manufacturing and Controls), and IT. Idorsia has granted Sosei Heptares a right of first negotiation and right of first refusal on certain pipeline assets for the Territory showing a clear commitment from Idorsia to continue to work with Sosei Heptares as a preferred partner. Territory: Australia, Brunei, Cambodia, Indonesia, Japan, Laos, Malaysia, Myanmar, New Zealand, Philippines, Singapore, South Korea, Thailand, Taiwan, and Vietnam. Notes to the editor About Sosei Heptares Sosei Heptares is a fully integrated biopharmaceutical company focused on bringing life-changing medicines based on world-class science to patients globally. Our vision is to become one of Japan's global biopharmaceutical champions. Sosei Heptares has a leading development capability and a profitable and growing commercial operation in Japan, which it intends to expand into additional selected markets in the Asia-Pacific region. Sosei Heptares is advancing a broad and deep pipeline of novel medicines created using its world-leading GPCR-targeted StaR® technology and structure-based drug design platform across multiple therapeutic areas, including neurology, immunology, gastroenterology, and inflammatory diseases. In addition, we have leveraged our unique discovery and development capabilities to establish multiple value-generating partnerships with world-leading biopharmaceutical companies, including AbbVie, Genentech (Roche), GSK, Lilly, Neurocrine Biosciences, Novartis, Pfizer, Sanofi and Takeda. Sosei Heptares is headquartered in Tokyo, Japan with corporate and R&D facilities in London and 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/ About Idorsia Idorsia Ltd is reaching out for more - We have more ideas, we see more opportunities and we want to help more patients. In order to achieve this, we will develop Idorsia into a leading biopharmaceutical company, with a strong scientific core. Headquartered near Basel, Switzerland - a European biotech-hub - Idorsia is specialized in the discovery, development and commercialization of small molecules to transform the horizon of therapeutic options. Idorsia has a 20-year heritage of drug discovery, a broad portfolio of innovative drugs in the pipeline, an experienced team of professionals covering all disciplines from bench to bedside, and commercial operations in Europe, Japan, and the US - the ideal constellation for bringing innovative medicines to patients. Idorsia was listed on the SIX Swiss Exchange (ticker symbol: IDIA) in June 2017 and has over 1,300 highly qualified specialists dedicated to realizing our ambitious targets. For further information, please contact Andrew C. Weiss Senior Vice President, Head of Investor Relations & Corporate Communications Idorsia Pharmaceuticals Ltd, Hegenheimermattweg 91, CH-4123 Allschwil +41 58 844 10 10 investor.relations@idorsia.com (mailto:investor.relations@idorsia.com) ? media.relations@idorsia.com (mailto:media.relations@idorsia.com) ? www.idorsia.com (http://www.idorsia.com) The above information contains certain "forward-looking statements", relating to the company's business, which can be identified by the use of forward-looking terminology such as "estimates", "believes", "expects", "may", "are expected to", "will", "will continue", "should", "would be", "seeks", "pending" or "anticipates" or similar expressions, or by discussions of strategy, plans or intentions. Such statements include descriptions of the company's investment and research and development programs and anticipated expenditures in connection therewith, descriptions of new products expected to be introduced by the company and anticipated customer demand for such products and products in the company's existing portfolio. Such statements reflect the current views of the company with respect to future events and are subject to certain risks, uncertainties and assumptions. Many factors could cause the actual results, performance or achievements of the company to be materially different from any future results, performances or achievements that may be expressed or implied by such forward- looking statements. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those described herein as anticipated, believed, estimated or expected. °

Quelle: dpa-Afx