IMPAX Comments On Aventis Pharmaceuticals Lawsuit Related to Generic Version of Allegra-D

April 01, 2002

April 1, 2002 -- IMPAX Laboratories, Inc. (Nasdaq:IPXL) today announced that Aventis Pharmaceuticals has filed a lawsuit against the Company in federal district court in Delaware alleging patent infringement related to IMPAX's filing of an Abbreviated New Drug Application (ANDA) for a generic version of Allegra-D® (Fexofenadine HCl/Pseudoephedrine HCl) Extended Release 60 mg/120mg Tablets.

Aventis Pharmaceuticals markets Allegra-D for the relief of symptoms associated with seasonal rhinitis in adults and children 12 years of age and older. U.S. sales of Allegra-D® Extended Release Tablets were over $350 million in 2001.

IMPAX announced that the U.S. Food and Drug Administration (FDA) had accepted the Company's filing of the ANDA for a generic version of Allegra-D on February 12, 2002. IMPAX made that application under Paragraph IV of the Hatch-Waxman Amendments stating the Company's belief that its Fexofenadine HCl/Pseudoephedrine HCl product does not infringe Aventis' listed patents on Allegra-D.

``When we filed our ANDA with the FDA we included a certification that stated the Company believes its product does not infringe Aventis' patents. Based on the process for this type of ANDA, the filing of this lawsuit is not surprising,'' stated Barry R. Edwards, Co-Chief Executive Officer of IMPAX Laboratories. ``We intend to vigorously defend our product and believe that this is just a tactic by Aventis to delay our approval.''

IMPAX currently has 14 Abbreviated New Drug Application (ANDA) filings pending at the FDA that address more than $8 billion in U.S. branded product sales during 2001. Nine of these filings were made under Paragraph IV of the Hatch-Waxman Amendments, one of which has received tentative approval from FDA.

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 niche 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. 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: