DEERFIELD, IL--(Marketwire - Mar 28, 2012) - Horizon Pharma, Inc. (NASDAQ: [ HZNP ]) today announced it has filed a patent infringement lawsuit in the United States District Court for the District of Delaware against Par Pharmaceutical, Inc. ("Par") and related to an Abbreviated New Drug Application ("ANDA") that Par filed with the U.S. Food and Drug Administration ("FDA") to market a generic version of DUEXIS® tablets.

The lawsuit claims infringement of Horizon's US patent 8,067,033 that is listed in the FDA's Orange Book and expires July 18, 2026. Horizon received a Paragraph IV Patent Certification from Par on February 15, 2012, advising that Par had filed an ANDA with the FDA for a generic version of DUEXIS® tablets. Par alleged that its generic version of DUEXIS® tablets would not infringe US patent 8,067,033 or the patent is invalid or unenforceable. Par 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 Par Pharmaceutical, Inc. and its parent Par Pharmaceutical Companies, Inc.

Horizon commenced the lawsuit within the 45 days required to automatically stay, or bar, the FDA from approving Par's ANDA for 30 months or until a district court decision that is adverse to the patent, 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 Par'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.