^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