Horizon Pharma Files Patent Infringement Lawsuit Against Watson Laboratories, Inc. - Florida for Filing an ANDA Against RAYOS(R)

DEERFIELD, IL--(Marketwired - Aug 27, 2013) - Horizon Pharma, Inc. (NASDAQ: HZNP) today announced it, along with SkyePharma from whom it has licensed certain RAYOS^® intellectual property, has filed a patent infringement lawsuit in the United States District Court for the District of New Jersey against Watson Laboratories, Inc. - Florida and certain related companies ("WLF") and related to an Abbreviated New Drug Application ("ANDA") that WLF filed with the U.S. Food and Drug Administration ("FDA") to market generic versions of RAYOS^® containing 1 mg, 2 mg and 5 mg of prednisone.

The lawsuit claims infringement of U.S. Patent Nos. 6,488,960, 6,677,326, 8,168,218, 8,309,124 and 8,394,407 that are listed in the FDA's Orange Book with the latest expiration January 7, 2028. Horizon received a Paragraph IV Patent Certification from WLF on July 15, 2013, advising that WLF had filed an ANDA with the FDA for a generic version of RAYOS^®. WLF alleged that its generic versions of RAYOS® would not infringe the subject U.S. patents or the patents are invalid or unenforceable. WLF has not advised Horizon as to the timing or status of the FDA's review of its filing, or whether it has complied with FDA requirements for proving bioequivalence. The defendants in the lawsuit are Watson Laboratories, Inc. - Florida, Actavis Pharma, Inc., Andrx Corp., and Actavis, Inc.

Horizon commenced the lawsuit within the 45 days required to automatically stay, or bar, the FDA from approving WLF's ANDA for 30 months or until a district court decision that is adverse to the subject patents, whichever may occur earlier.

About Horizon Pharma
Horizon Pharma, Inc. is a biopharmaceutical company that is developing and commercializing innovative medicines to target unmet therapeutic needs in arthritis, pain and inflammatory diseases. For more information, please visit www.horizonpharma.com.

Forward-Looking Statements
This press release contains forward-looking statements, including statements regarding whether the FDA is prevented from approving WLF's ANDA filing until a future time. These forward-looking statements are based on management's expectations and assumptions as of the date of this press release, and actual results may differ materially from those in these forward-looking statements as a result of various factors. These factors include, but are not limited to, whether Horizon would be successful in the patent infringement litigation. For a further description of these and other risks facing Horizon, please see the risk factors described in Horizon's filings with the United States Securities and Exchange Commission, including those factors discussed under the caption "Risk Factors" in those filings. Forward-looking statements speak only as of the date of this press release, and Horizon undertakes no obligation to update or revise these statements, except as may be required by law.