Impax Wins Round in Battle Over Claritin-D

Impax Laboratories Inc. on Wednesday won tentative regulatory approval for a generic version of Schering-Plough Corp.’s allergy drug Claritin-D, sending its shares up 3.8%.

Final Food and Drug Administration approval depends on the outcome of a patent lawsuit Schering-Plough brought against Impax, the expiration of a stay preventing approval of a generic for 30 months when a patent-infringement suit is filed and the expiration of any generic marketing exclusivity, Impax said.

Rival Andrx Corp. was the first generic-drug maker to seek approval for the 24-hour extended release form of the drug, which would give that company a six-month head start in the market before other generic versions were allowed under FDA rules, said Barry Edwards, co-chief executive of Impax.

Claritin-D had annual U.S. sales of about $539 million for the 12 months ended March 31.

Impax, which had sales of $6.6 million last year, is seeking FDA permission to sell generic copies of 15 brand-name products, including Aventis’ allergy medicine Allegra.

Schering-Plough’s lawsuit says Impax’s November 2000 filing with the FDA violated two patents covering Claritin. Those patents don’t expire until 2004 and 2014, Schering-Plough alleged in the lawsuit.

Shares of Impax, based in Hayward, Calif., rose 30 cents to $8.20 on Nasdaq. The shares have lost more than 30% of their value in the last 12 months.

Shares of Schering-Plough fell 5 cents to $26.50 on the New York Stock Exchange.