^Ad hoc announcement pursuant to Art. 53 LR

* A bondholders meeting is expected to take place on April 30, 2024, to

request the right to repay the bonds maturing in 2024, fully or partially in

shares of Idorsia

* Main investors Jean-Paul and Martine Clozel fully support this request

* Financial status as of March 31, 2024, to be published on April 17, 2024, in

conjunction with the invitation to the bondholder meeting

* Postponement of the Full Year 2023 and Q1 2024 Financial Results publication

to May 21, 2024, as granted by the SIX Exchange Regulation (SER)

Allschwil, Switzerland - April 11, 2024

Idorsia Ltd (SIX: IDIA) today announced that the company intends to call a

bondholder meeting for holders of its outstanding convertible bond maturing on

July 17, 2024 (ISIN: CH0426820350). The company will propose a change to the

current Terms and Conditions to be voted upon by bondholders.

Over the course of the past days, Idorsia has reached out to several of the

bondholders and received positive feedback on the amenability to adopting

additional Terms and Conditions: the proposed change to the Terms and Conditions

would give Idorsia the right at maturity, at its option, to repay the Bonds

fully or partially in shares of Idorsia. Any amount not repaid in shares would

be repaid in cash.

Idorsia's main investors, Jean-Paul and Martine Clozel, are fully committed to

Idorsia over the long-term and as such commit to participating in adopting

amended Terms and Conditions. Furthermore, Jean-Paul and Martine Clozel have

agreed to a 180-day lock-up period post maturity in the event that the

convertible bond will be repaid in shares, subject to customary exceptions.

For a full or partial settlement in shares, Idorsia would need to give notice on

the elected settlement alternative no later than 30 calendar days prior to the

maturity date. The reference price used to calculate the number of shares to be

delivered in case of a redemption in shares will be set as 95% of the average

daily volume-weighted average price (VWAP) of one share in the 20 consecutive

Trading Days commencing on (and including) the 20th Trading Day before the

Maturity Date, or if later, the Effective Date. Holders of the bonds who are

Institutional Investors will have the option to receive shares or opt for an

organized share sale which will be conducted by way of a private placement of

shares on or about the Maturity Date. Idorsia intends to include a provision in

the proposed amendment of the Terms and Conditions to provide bondholders

participating in such placement with some protection against potential downside

in connection with such placement. Up to CHF 10 million could be used by the

company to limit potential downside in a share placement.

Idorsia has appointed J.P. Morgan Securities plc to act as Dealer Manager for

the bondholder solicitation process.

The financial status as of March 31, 2024, is required in connection with the

bondholder meeting. Idorsia therefore intends to publish on April 17, 2024, the

formal invitation to the bondholder meeting concurrently with announcing its

unaudited financial status as of March 31, 2024. The bondholder meeting is

expected to take place on April 30, 2024.

Idorsia will further postpone the publication of its audited Full-Year 2023

Financial Results as well as the Q1 2024 Financial Results from the currently

scheduled April 25, 2024, to May 21, 2024. On April 8, 2024, the SIX Exchange

Regulation (SER) granted Idorsia a request for extension of the 2023 publication

and submission of the Annual Report until May 31, 2024. The rationale for this

request is related to the contemplated amendment of the convertible bond

maturing on July 17, 2024 (ISIN: CH0426820350) as announced today.

As required by SIX Exchange Regulation (SER), Idorsia hereby reprints paragraph

I of the SER's decision: Idorsia's request is granted as follows:

I. The exemption request of Idorsia (Issuer) dated 03 April 2024 regarding an

extension of the deadline to publish its 2023 annual report and to file such

report with SIX Exchange Regulation AG until 31 May 2024 at the latest is

granted with the following reservation (lit. a) and under the following

conditions (lit. b):

a. SIX Exchange Regulation AG reserves the right to suspend trading of the

registered shares of the Issuer in case its 2023 annual report is not

published in accordance with the provisions on ad hoc publicity (Art.

53 of the Listing Rules (Listing Rules dated 23 August 2023 )[LR] in

connection with the Directive on Ad hoc Publicity [DAH]) and not filed

with SIX Exchange Regulation AG until Friday, 31 May 2024, 11.59 pm CET,

at the latest.

b. Idorsia is required to publish a notice in accordance with the

provisions on ad hoc publicity (Art. 53 LR in connection with the DAH)

concerning this decision until Tuesday, 30 April 2024, 7.30 am CET, at

the latest.

The notice must contain:

* the unaltered reproduction of the wording of para. I. of this decision,

placed in a prominent position;

* the reasons for the application of the Issuer requesting an extension of the

deadline to publish its 2023 annual report and to file such report with SIX

Exchange Regulation AG (SER).

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 25-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 and North America - 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 750 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.

°