WASHINGTON: The Hyderabad-based drug maker's application with the U.S. Food and Drug Administration (FDA) seeks to sell 2 mg, 4 mg and 8 mg tablets of rosiglitazone maleate, the main ingredient in Avandia, the company said in a statement. The $1.3 billion Avandia is one of GlaxoSmithKline Plc's fastest growing products. With the challenge to Avandia, the Brentford, Britain-based Glaxo is facing the possibility of generic rivals to its four top-selling drugs. Generic drug makers such as Dr. Reddy's are filing earlier challenges to patented drugs to get six-month exclusive marketing rights allowed by U.S. law, according to Bloomberg news. Glaxo, Europe's largest drug maker, sued Dr. Reddy's in U.S. District Court in New Jersey, claiming patent infringement. The patent for Avandia's active ingredient expires in 2011, and the patents challenged by Dr. Reddy's expire in 2015 and 2017, Glaxo spokesman Martin Sutton said. Dr. Reddy's shares, which have risen 31 percent this year, rose by 22.1, or 1.9 percent, to 1173.7 on the Bombay Stock Exchange. GlaxoSmithKline shares declined 4 pence, or 0.3 percent, to 1,271 pence at the close of London trading. Glaxo's Canadian competitor Apotex Inc. started selling its version of Paxil, an anti-depressant with $2.1 billion in U.S. sales last year, after getting FDA approval last July. Paxil had global sales of $3.1 billion last year. Glaxo may lose more than half its U.S. sales of Paxil, its bi ggest product, to generic competition by 2005, analysts said.
Source: IANS