Shares in GlaxoSmithKline (GSK) fell sharply this morning after the company confirmed it had lost a key US court action to defend the patent on the antidepressant Paxil.
The company said it was sticking with its previously released earnings guidance but warned that it would have to reassess its forecasts if the launch of a generic version of Paxil, its biggest selling drug, became imminent.
A Chicago court ruled against GSK's claim that a generic version of Paxil by TorPharm, a unit of Canadian company Apotex, breached its patents.
Apotex could launch its version of the drug as early as September.
The Chicago judge ruled that GSK's patents were valid until 2006 but were not infringed by TorPharm's version of the drug. GSK said it will appeal the Chicago ruling.
It said it will also continue with patent infringement cases against Apotex and other generic companies in a Philadelphia court. No trial date has been set for that case, however.
GSK said that with its appeal and the Philadelphia cases pending, the possible timing of a generic Paxil remains unclear.
Paxil came on the market in the United States in early 1993, and the first generic company, Apotex, sought marketing approval in 1998 - only five years after first launch.
AFP