GlaxoSmithKline lose patent battle

Pharmaceuticals giant GlaxoSmithKline today said it had lost a key court case in the US over the patent to its anti-depressant Paxil.

Shares fell 3% after the group said that a court in Chicago had ruled that a subsidiary of rival drugs group Apotex did not infringe GlaxoSmithKline’s patent with a similar product.

The group today pledged to appeal against the ruling and stuck by previously stated guidance on earnings for 2003 which depend on there being no competition to Paxil in the US from generic forms of the drug.

The group holds a patent in the US covering the “hemihydrate” version of Paxil – a crystalline form of the chemical paroxetine hydrochloride – until 2006.

Apotex wants to market a version of paroxetine hydrochloride which GSK believes infringes their patent as it includes elements of the hemihydrate form of the chemical.

Judge Richard Posner ruled that although Apotex’s product could contain elements of the hemihydrate form, it did not do so in sufficient quantity to break GSK’s patent.

In a statement GlaxoSmithKline said it would be appealing against the judge’s interpretation.

The group is also pursuing an action in a court in Philadelphia relating to patents covering other aspects of Paxil involving Apotex and other companies.

No date has yet been set for the case.

The group stood by guidance which forecast growth in earnings per share in the high single figures as long as no generic versions of Paxil appear on the US market.

GSK said today that should the launch of a generic version of paroxetine hydrochloride be imminent it would reassess that guidance.

Shares fell 38p to 1084p.