Schering Seeks Return of Claritin Patent

Schering-Plough Corp. argued before a U.S. appeals court that a judge erred in invalidating a patent that warded off generic competition to Claritin, once the company’s top seller.

The allergy drug, which accounted for almost a third of company revenue in 2001, is now sold as a nonprescription drug. Meanwhile, Wyeth is selling a competing generic equivalent, Alavert, and other rivals are expected to follow unless the U.S. Court of Appeals for the Federal Circuit reinstates the patent, which expires in October 2004.

The patent covers a metabolite created in the human body after loratadine, the key ingredient in Claritin, is ingested. A federal judge last year ruled that the patent doesn’t disclose anything new, since the metabolite is an inherent result of loratadine, but Schering, based in Kenilworth, N.J., disagrees.