IMPAX Announces Merck's Withdrawal of Lawsuit Related to Generic Version of Sinemet CR

April 9, 2003

April 9, 2003--IMPAX Laboratories, Inc. (Nasdaq:IPXL) today announced that Merck & Co. Inc. has withdrawn its lawsuit alleging patent infringement related to IMPAX's filing of an Abbreviated New Drug Application (ANDA) for a generic version of Sinemet® CR tablets. The lawsuit had been filed in the federal district court in Delaware in February 2003.

Sinemet CR is used to treat patients with Parkinsonism, and is exclusively distributed in the U.S. by Bristol-Myers Squibb Company. U.S. sales of Sinemet CR and the currently marketed generic equivalent were approximately $154 million in the 12 months ended December 31, 2002, according to IMS Health data. The FDA accepted for review IMPAX's application to market a generic version of Merck's Sinemet CR in December 2002.

IMPAX has 19 applications pending at the FDA, including three tentatively approved, that address more than $5.8 billion in U.S. branded product sales for the 12 months ended December 31, 2002. Thirteen of these filings were made under Paragraph IV of the Hatch-Waxman Amendments.

IMPAX Laboratories, Inc. is a technology based specialty pharmaceutical company applying its formulation expertise and drug delivery technology to the development of controlled-release and specialty generics, in addition to the development of branded products. IMPAX markets its generic products through its Global Pharmaceuticals division and intends to market its branded products through the IMPAX Pharmaceuticals division. Additionally, where strategically appropriate, IMPAX has developed marketing partnerships to fully leverage its technology platform. IMPAX Laboratories is headquartered in Hayward, California, and has a full range of capabilities in its Hayward and Philadelphia facilities. For more information, please visit the Company's Web site at: