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• Idorsia successfully completes the offering of 11,912,000 new shares with gross proceeds of CHF 305 million
• Idorsia successfully completes the offering of CHF 200 million of senior convertible bonds

Allschwil, Switzerland - July 11, 2018
Idorsia Ltd (SIX: IDIA, "Idorsia") today announced that it has successfully placed 11,912,000 new shares (the "Offer Shares"), corresponding to approximately 10% of Idorsia's currently issued share capital, by way of an accelerated bookbuilding. Additionally, Idorsia successfully placed CHF 200 million of senior unsecured convertible bonds (the "Bonds") due 2024. The net proceeds from the concurrent offerings will be used to fund the ongoing research and development of Idorsia's development pipeline and will allow Idorsia to fund the Phase 3 development of Idorsia's promising late-stage pipeline comprising aprocitentan, clazosentan, lucerastat and nemorexant, as well as its diverse early-stage and preclinical pipeline.

As part of the concurrent offerings, Idorsia agreed to a 180-day lock-up period. Jean-Paul and Martine Clozel, the main shareholders of Idorsia, purchased 28.4% of the Offer Shares and 28.4% of the Bonds to maintain their current ownership in Idorsia. They have also agreed to a lock-up period of 180 days, subject to customary exceptions.

Issuance of new registered shares
Idorsia placed 11,912,000 new registered shares of CHF 0.05 par value each at CHF 25.62 per new share. The Offer Shares, corresponding to approximately 10% of Idorsia's currently issued share capital, will be issued from Idorsia's existing authorized share capital. It is anticipated that the listing and the admission to trading of the Offer Shares according to the International Reporting Standard of SIX Swiss Exchange will become effective on or around July 13, 2018 (the "First Day of Trading"). The Offer Shares will rank pari passu with the existing shares.

Issuance of senior unsecured convertible bonds
The Bonds will have a maturity of 6 years and will be convertible into 5.9 million registered shares of Idorsia, sourced from existing listed conditional share capital, on or after August 27, 2018. The Bonds will have a coupon of 0.75% and a conversion price of CHF 33.95, corresponding to a conversion premium of 32.5% above the bookbuilding price of the Offer Shares. Holders of the Bonds who convert their Bonds will receive Idorsia shares with a par value of CHF 0.05 per Idorsia share. Idorsia will be entitled to redeem the Bonds at their principal amount (plus accrued interest) in accordance with the terms and conditions of the Bonds at any time (i) on or after August 7, 2022, if the price of an Idorsia share is equal to or exceeds 150% of the then prevailing conversion price over a certain period or (ii) if less than 15% of the aggregate principal amount of the Bonds remains outstanding. The Bonds will be issued and, unless previously converted or repurchased and cancelled, will be redeemed at 100% of their principal amount with a denomination of CHF 200,000 per Bond. The interest on the Bonds will be subject to Swiss withholding tax (which is currently at a rate of 35%).

The settlement date of the Bonds is expected to be on or around July 17, 2018. Application for the listing and trading of the Bonds according to the Standard for Bonds of SIX Swiss Exchange will be made at a later stage.

Credit Suisse and Goldman Sachs International were acting as Joint Bookrunners and Octavian as Selling Agent on these concurrent offerings.

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 one of Europe's leading biopharmaceutical companies, with a strong scientific core.

Headquartered in Switzerland - a biotech-hub of Europe - Idorsia is specialized in the discovery and development of small molecules, to transform the horizon of therapeutic options. Idorsia has a broad portfolio of innovative drugs in the pipeline, an experienced team, a fully-functional research center, and a strong balance sheet - the ideal constellation to bringing R&D efforts to business success.

Idorsia was listed on the SIX Swiss Exchange (ticker symbol: IDIA) in June 2017 and has over 650 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 (0) 58 844 10 10
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.

THIS PRESS RELEASE IS NOT BEING ISSUED IN THE UNITED STATES OF AMERICA (INCLUDING ITS TERRITORIES AND POSSESSIONS) (THE "UNITED STATES" OR "US") AND SHOULD NOT BE DISTRIBUTED TO UNITED STATES PERSONS OR PUBLICATIONS WITH A GENERAL CIRCULATION IN THE UNITED STATES. THIS DOCUMENT DOES NOT CONSTITUTE AN OFFER OR INVITATION TO SUBSCRIBE FOR OR PURCHASE ANY SECURITIES NOR DOES IT CONSTITUTE A PROSPECTUS WITHIN THE MEANING OF ARTICLES 652A OR 1156 OF THE SWISS CODE OF OBLIGATIONS OR A LISTING PROSPECTUS PURSUANT TO THE LISTING RULES OF THE SIX SWISS EXCHANGE. ANY DECISION TO PURCHASE ANY SECURITIES REFERRED TO HEREIN SHOULD BE SOLELY BASED ON THE RELEVANT PROSPECTUS. IN ADDITION, NEITHER THE OFFER SHARES, THE BONDS NOR THE SHARES OF IDORSIA LTD INTO WHICH THE BONDS ARE CONVERTIBLE HAVE BEEN OR WILL BE REGISTERED UNDER THE UNITED STATES SECURITIES LAWS AND MAY NOT BE OFFERED, SOLD OR DELIVERED WITHIN THE UNITED STATES ABSENT REGISTRATION UNDER, OR AN APPLICABLE EXEMPTION FROM THE REGISTRATION REQUIREMENTS, OF THE UNITED STATES SECURITIES LAWS. NO PUBLIC OFFERING OF SECURITIES IS BEING MADE IN THE UNITED STATES.

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IN ADDITION, IF AND TO THE EXTENT THAT THIS PRESS RELEASE IS COMMUNICATED IN, OR THE OFFER OF SECURITIES TO WHICH IT RELATES IS MADE IN, ANY MEMBER STATE OF THE EUROPEAN ECONOMIC AREA ("EEA")THAT HAS IMPLEMENTED DIRECTIVE 2003/71/EC, AS AMENDED (TOGETHER WITH DIRECTIVE 2010/73/EU, TO THE EXTENT IMPLEMENTED IN ANY EEA MEMBER STATE AND INCLUDES ANY APPLICABLE IMPLEMENTING MEASURES IN ANY EEA MEMBER STATE, THE "PROSPECTUS DIRECTIVE") ("EACH, A "RELEVANT MEMBER STATE"), THIS PRESS RELEASE AND THE OFFERING OF ANY SECURITIES DESCRIBED HEREIN ARE ONLY ADDRESSED TO AND DIRECTED AT PERSONS IN THAT MEMBER STATE WHO ARE QUALIFIED INVESTORS WITHIN THE MEANING OF THE PROSPECTUS DIRECTIVE (OR WHO ARE OTHER PERSONS TO WHOM THE OFFER MAY LAWFULLY BE ADDRESSED) AND MUST NOT BE ACTED ON OR RELIED ON BY OTHER PERSONS IN THAT MEMBER STATE.

IF LOCATED IN A RELEVANT MEMBER STATE, EACH PERSON WHO INITIALLY ACQUIRES ANY SECURITIES, AND TO THE EXTENT APPLICABLE ANY FUNDS ON BEHALF OF WHICH SUCH PERSON ACQUIRES SUCH SECURITIES THAT ARE LOCATED IN A RELEVANT MEMBER STATE, OR TO WHOM ANY OFFER OF SECURITIES MAY BE MADE WILL BE DEEMED TO HAVE REPRESENTED, ACKNOWLEDGED AND AGREED THAT IT IS A QUALIFIED INVESTOR AS DEFINED ABOVE.

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