11:46am UK, Wednesday January 15, 2003

GlaxoSmithKline has been told the date of a key trial over US patents on its best-selling anti-depressant, Paxil, is February 5 in Chicago.

The court will hear arguments between GSK and Canadian generic drug-maker Apotex over patents covering the so-called hemihydrate form of the medicine, which expires in 2006.

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The case is viewed by some analysts as the most important in a number pending over Paxil patents in the US.

Unexpected victory

The drug, belonging to the same class of anti-depressants as Prozac and developed by Eli Lilly, has been a huge commercial success for GSK.

It generated global sales of £1.86bn in 2001, with the US as its biggest single market.

GSK had an unexpected victory late last month in its complex battle to defend Paxil from copycat competition.

Earnings growth

A Philadelphia court found against the firm in only one of four challenges relating to the so-called anhydrous form of the drug.

Paxil is seen as vital to near-term earnings growth at Europe's largest drug-maker.

GSK has said it expects to deliver growth in earnings per share of at least 10% in 2002 and the high single digits in 2003, assuming it successfully defends its Paxil patents in the US.