Horizon Therapeutics plc Confirms Preliminary Discussions Regarding Potential Offer

The Board of Horizon Therapeutics plc (Nasdaq: HZNP) (“Horizon” or the “Company”) confirms that it is engaged in highly preliminary discussions with Amgen Inc., Janssen Global Services, LLC and Sanofi (each a "Possible Offeror") which may or may not lead to an offer being made for the entire share capital of the Company. There can be no certainty that any offer will be made for the Company.

In accordance with Rule 2.6 of the Irish Takeover Rules, each of the Possible Offerors is required, no later than 5:00 pm (New York time) on Jan. 10, 2023, to either (i) announce a firm intention to make an offer for the Company in accordance with Rule 2.7 of the Irish Takeover Rules; or (ii) announce that it does not intend to make an offer for the Company, in which case the announcement will be treated as a statement to which Rule 2.8 of the Irish Takeover Rules applies. This deadline will only be extended with the consent of the Irish Takeover Panel in accordance with Rule 2.6(c) of the Irish Takeover Rules, at the request of the Company.

Important Notices

About Horizon

Horizon Therapeutics plc is focused on the discovery, development and commercialization of medicines that address critical needs for people impacted by rare, autoimmune and severe inflammatory diseases. Our pipeline is purposeful: We apply scientific expertise and courage to bring clinically meaningful therapies to patients. We believe science and compassion must work together to transform lives. For more information on how we go to incredible lengths to impact lives, please visit www.horizontherapeutics.com.

Responsibility Statement

The directors of the Company accept responsibility for the information contained in this announcement. To the best of the knowledge and belief of the directors (who have taken all reasonable care to ensure that such is the case), the information contained in this announcement is in accordance with the facts and does not omit anything likely to affect the import of such information.

Disclosure Requirements of the Irish Takeover Rules

Under Rule 8.3(a) of the Irish Takeover Rules, any person who is 'interested' in 1% or more of any class of 'relevant securities' of the Company or a securities exchange offeror (being any offeror other than an offeror which has announced that its offer is, or is likely to be, solely in cash) must make an 'opening position disclosure' following the commencement of the 'offer period' and, if later, following the announcement in which any securities exchange offeror is first identified. An 'opening position disclosure' must contain, among other things, details of the person's 'interests' and 'short positions' in any 'relevant securities' of each of (i) the Company and (ii) any securities exchange offeror(s). An 'opening position disclosure' by a person to whom Rule 8.3(a) applies must be made by no later than 3:30 pm (New York time) on the day that is ten 'business days' following the commencement of the ‘offer period’ and, if appropriate, by no later than 3:30 pm (New York time) on the day that is ten 'business days' following the announcement in which any securities exchange offeror is first identified.