^Ad hoc announcement pursuant to Art. 53 LR

Allschwil, Switzerland - June 06, 2023

Idorsia Ltd (SIX: IDIA) today announced that it has entered into exclusive

negotiations with an undisclosed party regarding its operating businesses in the

Asia Pacific (ex-China) region, including selected license rights to products

from Idorsia's portfolio in those territories, for a total consideration of up

to CHF 400 million.

This prospective strategic transaction is subject to completion of satisfactory

due diligence and legal documentation. Further announcements will be made as

appropriate.

André C. Muller, Chief Financial Officer of Idorsia, added:

"This prospective strategic transaction would allow Idorsia to realize the

significant value we have created in the region, and would extend our cash

runway, while maintaining relationships for the future development and

commercialization of our pipeline programs in the region. I would expect the

potential transaction to be completed during July, subject to completion of

satisfactory due diligence and legal documentation."

Notes to the editor

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

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.

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