DRUGS firm GlaxoSmithKline claimed a partial victory in its battle to prevent the launch of generic competition to its key Paxil treatment.

The pharmaceutical company said there were still "significant hurdles" facing its rivals despite a US judge dismissing one patent related to the anti-depressant.

The judge ruled in Glaxo's favour on another patent and split the decision on the remaining two in a case raised by Canadian firm Apotex.

Glaxo, which reiterated its earnings guidance for 2002 and 2003, has set aside almost £100m to fight looming patent battles.

Major pharmaceutical firms are under mounting pressure to see off generic rivals and protect revenue generated from their major treatments.

Glaxo's problem is two-fold, given reports of limited success in discovering new drugs to fill its development pipeline.

Paxil was launched in the US in 1993 and generated £1.8bn of sales last year. The patents protecting the drug are due to expire in 2006.

The US judge's verdict was a summary judgement that precedes a main trial hearing. A date for the trial has yet to be set..