The unaudited condensed consolidated financial statements presented herein have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, the financial statements do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments, including normal recurring adjustments, considered necessary for a fair statement of the financial statements have been included. Operating results for the three months ended March 31, 2020 are not necessarily indicative of the results that may be expected for the year ending December 31, 2020. The December 31, 2019 condensed consolidated balance sheet was derived from audited financial statements, but does not include all disclosures required by GAAP.

Unless otherwise indicated or the context otherwise requires, references to “Horizon”, the “Company”, “we”, “us” and “our” refer to Horizon Therapeutics plc and its consolidated subsidiaries.

During the three months ended March 31, 2020, the Company recorded out of period adjustments that decreased income tax benefit by $3.2 million and increased share-based compensation expense by $1.9 million to correct for expenses that should have been recorded in the year ended December 31, 2019. The Company evaluated the materiality of the adjustments on prior period financial statements and making the adjustments in the current period, and concluded the effect of the adjustments were immaterial to both the current and prior period financial statements.

Horizon is focused on researching, developing and commercializing medicines that address critical needs for people impacted by rare and rheumatic diseases. The Company’s pipeline is purposeful: it applies scientific expertise and courage to bring clinically meaningful therapies to patients. Horizon believes science and compassion must work together to transform lives. The Company has two reportable segments, the orphan segment and the inflammation segment, and currently markets eleven medicines in the areas of rare diseases, gout, ophthalmopathy and inflammation.

Effective in the first quarter of 2020, the Company (i) reorganized its commercial operations and moved responsibility for and reporting of RAYOS® to the inflammation segment and (ii) renamed the orphan and rheumatology segment the orphan segment. Net sales generated by TEPEZZA™, which was approved on January 21, 2020, are reported as part of the renamed orphan segment.

As of March 31, 2020, the Company’s marketed medicines consisted of the following:

Orphan

KRYSTEXXA® (pegloticase injection), for intravenous infusion

RAVICTI® (glycerol phenylbutyrate) oral liquid

PROCYSBI® (cysteamine bitartrate) delayed-release capsules, for oral use

ACTIMMUNE® (interferon gamma-1b) injection, for subcutaneous use

TEPEZZA (teprotumumab-trbw), for intravenous infusion

BUPHENYL® (sodium phenylbutyrate) Tablets and Powder

QUINSAIR™ (levofloxacin) solution for inhalation

Inflammation

PENNSAID® (diclofenac sodium topical solution) 2% w/w (“PENNSAID 2%”), for topical use

DUEXIS® (ibuprofen/famotidine) tablets, for oral use

RAYOS (prednisone) delayed-release tablets

VIMOVO® (naproxen/esomeprazole magnesium) delayed-release tablets, for oral use