^Ad hoc announcement pursuant to Art. 53 LR

Allschwil, Switzerland - May 21, 2024

Idorsia Ltd (SIX: IDIA) today announced its financial results for the full year

of 2023.

Business highlights

* Sale of Idorsia Asia-Pacific operations (excluding China): Sold to Nxera

Pharma (previously known as Sosei Heptares) for a total consideration of CHF

400 million in July 2023.

* Cost reduction initiative: Delivering a 50% reduction in fixed cost at Swiss

headquarters fully effective in early 2024.

* Aprocitentan: Worldwide rights reacquired from Janssen for a conditional

consideration of CHF 306 million in September 2023.

Commercial highlights

* QUVIVIQ(TM) (daridorexant): Total net sales of CHF 31 million in 2023.

* QUVIVIQ: Expanded access and availability in the US, Canada and across

Europe.

Financial highlights FY 2023

* Net revenue FY 2023 at CHF 152 million.

* US GAAP operating expenses FY 2023 at CHF 409 million and non-GAAP operating

expenses FY 2023 at CHF 654 million.

* US GAAP operating loss FY 2023 of CHF 255 million and non-GAAP operating

loss of CHF 501 million.

Jean-Paul Clozel, MD and Chief Executive Officer, commented:

"During 2023, we made great progress with expanding the availability of QUVIVIQ

and patient access in the US, Canada, and across Europe. QUVIVIQ is rapidly

being recognized by specialists as a major advance in the field of insomnia.

PIVLAZ became a very successful drug in Japan, and regulatory submissions were

advanced for aprocitentan in the US and EU. As the development and launch of

these three products required substantial financial investments, there was a

need to lower our costs. Accordingly, we reduced our headcount and prioritized

our portfolio assets; we monetized our Asia-Pacific operations; and we began

negotiations with potential partners. All these actions have been essential to

the future of the company."

André C. Muller, Chief Financial Officer, commented:

"2023 was a year of adaptation for Idorsia. When it became clear that we would

not hit our original sales targets, we needed to take measures to reduce and

control our cost base to deliver on our operating guidance. Furthermore, we

needed to advance several funding and business initiatives to extend our cash

runway. Our activities resulted in a one-off income related to the Nxera Deal

and substantially reduced operating expenses throughout all functions meaning we

delivered a significantly lower operating loss than forecast. With the reduced

cost base, two marketed or close-to-market products, and a rich unencumbered

portfolio of innovative assets, Idorsia entered 2024 in a much stronger

position."

Financial results FY 2023

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US GAAP results Fourth

Full Year Quarter

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in CHF millions, except EPS (CHF) and number of

shares (millions) 2023 2022 2023 2022

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Net revenues 152 97 22 54

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Operating expenses (409) (900) (134) (247)

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Operating income (loss) (255) (803) (111) (193)

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Net income (loss) (298) (828) (117) (193)

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Basic EPS (1.67) (4.67) (0.65) (1.09)

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Basic weighted average number of shares 178.2 177.4 178.6 177.5

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Diluted EPS (1.67) (4.67) (0.65) (1.09)

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Diluted weighted average number of shares 178.2 177.4 178.6 177.5

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US GAAP net revenue of CHF 152 million in 2023 (CHF 97 million in 2022)

consisted of product sales of QUVIVIQ (CHF 30.9 million) and PIVLAZ (CHF 34.4

million), the one-off impact of the Nxera Deal (CHF 68 million), a CHF 9 million

milestone payment from Santhera, a revenue share from Johnson & Johnson (CHF 5

million) and other contract revenues mainly Mochida (CHF 4 million), and

Neurocrine Biosciences, Inc. (CHF 2 million).

US GAAP operating expenses in 2023 amounted to CHF 409 million (CHF 900 million

in 2022), of which CHF 7 million related to cost of sales (CHF 6 million in

2022), CHF 294 million to R&D expenses (CHF 383 million in 2022) and CHF 392

million to SG&A expenses (CHF 509 million in 2022) CHF 11 million restructuring

charges and a one-off income of CHF 298 million relating to the Nxera Deal.

US GAAP net loss in 2023 amounted to CHF 298 million (CHF 828 million in 2022).

The decrease of the net loss was mainly attributable to the one-off income

related to the Nxera Deal but was also driven by higher revenues and lower

operating expenses throughout all functions.

The US GAAP net loss resulted in a net loss per share of CHF 1.67 (basic and

diluted) in 2023, compared to a net loss per share of CHF 4.67 (basic and

diluted) in 2022.

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Non-GAAP* measures Fourth

Full Year Quarter

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in CHF millions, except EPS (CHF) and number of

shares (millions) 2023 2022 2023 2022

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Net revenues 152 97 22 54

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Operating expenses (654) (854) (137) (234)

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Operating income (loss) (501) (757) (115) (180)

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Net income (loss) (542) (782) (121) (186)

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Basic EPS (3.04) (4.41) (0.68) (1.05)

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Basic weighted average number of shares 178.2 177.4 178.6 177.5

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Diluted EPS (3.04) (4.41) (0.68) (1.05)

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Diluted weighted average number of shares 178.2 177.4 178.6 177.5

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* Idorsia measures, reports and issues guidance on non-GAAP operating

performance. Idorsia believes that these non-GAAP financial measurements more

accurately reflect the underlying business performance and therefore provide

useful supplementary information to investors. These non-GAAP measures are

reported in addition to, not as a substitute for, US GAAP financial performance.

Non-GAAP net loss in 2023 amounted to CHF 542 million: The CHF 244 million

difference versus US GAAP net loss was mainly due to the one-off effect of the

Nxera Deal (CHF 305 million income), depreciation and amortization (CHF 24

million), share-based compensation (CHF 23 million), restructuring charges (CHF

11 million) and a loss on marketable securities (CHF 4 million).

The non-GAAP net loss resulted in a net loss per share of CHF 3.04 (basic and

diluted) in 2023, compared to a net loss per share of CHF 4.41 (basic and

diluted) in 2022.

Nxera Deal (previously known as Sosei Deal)

In July 2023, Idorsia sold its operating businesses in the Asia-Pacific

(excluding China) region to Sosei Heptares (now known as Nxera Pharma) for a

total consideration of CHF 400 million. The territories within the scope of the

transaction are Australia, Brunei, Cambodia, Indonesia, Japan, Laos, Malaysia,

Myanmar, New Zealand, Philippines, Singapore, South Korea, Thailand, Taiwan, and

Vietnam (hereafter the "Territories").

The Nxera deal includes the sale of Idorsia's Japanese and South Korean

affiliates, the assignment of the license for PIVLAZ (clazosentan) for the

Territories and of the (co-) exclusive license for daridorexant for the

Territories, and the assignment of all potential milestones in connection with

the co-exclusive license for daridorexant granted to Mochida Pharmaceutical for

Japan. The Nxera deal also includes an option for Nxera Pharma to license

cenerimod and lucerastat for development and commercialization in the

Territories, with option fees of CHF 3 million and 7 million, respectively, and

subsequent payment of high-single-digit royalties on net sales in the

Territories.

Cost reduction initiative

In July 2023, Idorsia launched a cost reduction initiative, targeting a

reduction of around 50% in its fixed cost base at headquarters.

Approximately 475 positions at headquarters in Allschwil, Switzerland, were

eliminated through a combination of cancellation of new positions, natural

turnover, non-renewal of temporary positions, and terminations, mainly in

Research & Development and associated support functions. The reduction of

positions resulted in a restructuring charge of CHF 11 million.

The initiative has been concluded, with the reduction of costs becoming fully

effective in early 2024.

Reacquisition of aprocitentan rights

In September 2023, Idorsia reached an agreement to reacquire the development and

commercialization rights for aprocitentan from Johnson & Johnson Innovative

Medicine (formerly known as Janssen Biotech, Inc.). In return, Idorsia will pay

Johnson & Johnson Innovative Medicine a conditional consideration up to a total

cap of CHF 306 million, depending on Idorsia's revenues, as follows:

* 30% of any consideration received by Idorsia from a potential out-licensing

or divestment of aprocitentan,

* 10% of any consideration received by Idorsia from a potential out-licensing

or the divestment of any other Idorsia product, following the first approval

of aprocitentan, and

* low- to mid-single-digit royalties on total group product net sales,

beginning from the quarter after first aprocitentan approval.

Johnson & Johnson Innovative Medicine will retain licenses in the pulmonary

hypertension field.

Liquidity and indebtedness (as of December 31, 2023)

At the end of 2023, Idorsia's liquidity amounted to CHF 145 million.

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(in CHF millions) Dec 31, 2023 Sep 30, 2023 Dec 31, 2022

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Liquidity

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Cash and cash equivalents 145 205 146

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Short-term deposits - 50 320

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Total liquidity* 145 255 466

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Indebtedness

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Convertible loan 335 335 335

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Convertible bond 796 796 795

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Other financial debt 162 162 162

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Total indebtedness 1,293 1,292 1,292

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*rounding differences may occur

Results Day Center

Investor community: To make your job easier, we provide all relevant

documentation via the Results Day Center on our corporate website:

www.idorsia.com/results-day-center (http://www.idorsia.com/results-day-center).

Human Resources

Idorsia reduced 423 positions worldwide in 2023, bringing the total number of

employees (permanent, post-doc, and apprentices) to 938 (2022: 1,361).

Annual Report

Details of the activities performed in 2023 are available in Idorsia's 2023

Annual Report, consisting of the Business Report, Governance Report,

Compensation Report, Financial Report, and for the first time, Sustainability

Report, at www.idorsia.com/annual-report (http://www.idorsia.com/annual-report).

Note to Shareholders

The Annual General Meeting (AGM) of Shareholders to approve the Annual Report of

the year ending December 31, 2023, will be held on Thursday, June 13, 2024.

In order to vote at the Annual General Meeting, shareholders must be registered

in the company's shareholder register by June 4, 2024, at the latest.

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.

°