Horizon Therapeutics Public : J.P. Morgan Healthcare Conference

Tim Walbert

Chairman, President and Chief Executive Officer

HorizonTherapeutics.com

Forward-looking Statements

This presentation contains forward-looking statements, including, but not limited to, statements related to Horizon's full-year 2020 net sales

and adjusted EBITDA guidance; expected financial performance and operating results for the year ended December 31, 2020, and in future periods, including potential growth in net sales of certain of Horizon's medicines; development plans; expected timing of clinical trials, studies and regulatory submissions; potential market opportunity for and benefits of Horizon's medicines and medicine candidates; and business and other statements that are not historical facts. These forward-looking statements are based on Horizon's current expectations and inherently involve significant risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks that Horizon's actual financial and operating results may differ from its estimates, expectations or goals; Horizon's ability to grow net sales from existing medicines; uncertainty with respect to the COVID-19 pandemic and actions taken to slow its spread, including impacts on supply and sales of Horizon's medicines and potential delays in clinical trials; the availability of coverage and adequate reimbursement and pricing from government and third-party payers; risks relating to Horizon's ability to successfully implement its business strategies; risks inherent in developing novel medicine candidates and existing medicines for new indications; risks associated with regulatory approvals; risks in the ability to recruit, train and retain qualified personnel; competition, including potential generic competition; the ability to protect intellectual property and defend patents; regulatory obligations and oversight, including any changes in the legal and regulatory environment in which Horizon operates and those risks detailed from time-to-time under the caption "Risk Factors" and elsewhere in Horizon's filings and reports with the SEC. Horizon undertakes no duty or obligation to update any forward-looking statements contained in this presentation as a result of new information.

2

1

2

3

4

Horizon Overview	Our Pipeline is Our Priority	TEPEZZA®	KRYSTEXXA®
and Strategic	Expanding to Drive	One of the	Transformed a
Transformation	Sustainable	Most Successful	10-Year-Old Biologic
	Long-term Growth	Rare Disease	to a High-Growth
		Medicine Launches	Medicine

3

Horizon Exceeded High End of Full-Year 2020 Net Sales and Adjusted EBITDA Guidance

Outstanding Execution Resulted in Total Shareholder Returns Significantly Outperforming NBI

	Strong Financial Results and Strategic Execution		Generated High Returns
		for Shareholders
•		Year-Over-Year Net Sales Growth		Total Shareholder Return at Dec. 31, 2020
2020 net sales and adjusted EBITDA	$ in billions

• 2020 net sales
• 2020 net sales

• at Dec. 31, 2020 of

	>65%	387%
	>$2.14
	NBI
$1.30		HZNP
		238%
2019	2020

Year-Over-Year Adj. EBITDA Growth

$ in millions
>95%	102%

	>$940
$483		26%	41%	38%
2019	2020	1-year	3-year	5-year

NBI: Nasdaq Biotechnology Index

Note: The Company exceeded the high end of previously announced FY20 net sales and adjusted EBITDA guidance ranges of $2.12B to $2.14B and $920M to $940M, respectively. The Company provided preliminary financial results that are unaudited and subject to adjustment as per the Jan. 11, 2021 press release. Horizon expects to report its final 2020 financial results in February 2021. Adjusted EBITDA is a non-GAAP financial measure. See "Note Regarding Use of Non-GAAP Financial Measures" slide for more detail.

4