KENILWORTH, N.J. (AP) — Schering-Plough Corp. has settled patent litigation with drug maker Orchid Chemicals & Pharmaceuticals Ltd., which sought to make generic versions of Schering-Plough’s allergy drug Clarinex. The agreement marks the end of all pending suits filed and consolidated since 2006 in the U.S. District Court for the District of New Jersey against several generic drug manufacturers that had wanted to market solid oral doses of Clarinex, also known generically as desloratadine, in the U.S. before certain Schering patents had expired. Clarinex tablets and RediTabs treat symptoms of seasonal allergies causing inflamed nasal membranes and runny nose, as well as chronic hives. Clarinex-D 24 Extended Release Tablets are a once-daily prescription antihistamine and decongestant combination treatment for 24-hour relief of nasal and non-nasal allergy symptoms. Total U.S. sales for Clarinex products were $295 million in 2008. Schering-Plough, which is being acquired by Whitehouse Station, N.J.-based Merck for $41.1 billion, said the deal will allow Orchid to launch a generic version of the company’s orally disintegrating RediTabs in the U.S. on Jan. 1, 2012, and Clarinex-brand 5 milligram tablets on July 1 of that year. Kenilworth, N.J.-based Schering holds various patents related to Clarinex that extend to 2022. Since 2006, the drug maker has resolved similar disputes with Caraco Pharmaceutical Laboratories Ltd., Dr. Reddy’s Laboratories Inc., GeoPharma Inc., Mylan Pharmaceuticals Inc., Perrigo Co., Ranbaxy Laboratories Ltd. and Watson Pharmaceuticals Inc., among others.