Amgen has filed suit against Swiss drug major Roche for infringing its patents on erythropoietin, the red blood cell growth factor that represents a $5 billion dollar franchise for the world’s largest biotechnology company.

The catalyst for the lawsuit is Roche’s decision to develop a long-acting EPO product, called CERA (R744), which will be a direct competitor to Amgen’s own Aranesp (darbepoetin alfa) and Epogen (epoetin alfa). CERA is in Phase III trials for renal anaemia and is scheduled for regulatory submission in 2006.

The lawsuit claims that various Roche units - F Hoffmann-La Roche Ltd, Roche Diagnostics GmbH, and Hoffmann-La Roche Inc - are planning to market one or more anaemia treatments that infringe on six patents protecting Epogen. Roche insists CERA is different to Epogen and is not covered by Amgen’s patent estate for the drug.

If approved, CERA, which is dosed just once every two weeks, would compete head-to-head with Aranesp, Amgen’s long-acting version of EPO, which is given weekly bi-weekly. Epogen is dosed three times a week.

Aranesp is currently Amgen’s fastest-growing product, with sales up 38% in the third quarter to $840 million dollars [[20/10/05d]], and has assumed even more importance to the biotech group of late as Epogen sales are on the slide, dropping 12% to $599 million in the third quarter.

The suit seeks a permanent injunction against Roche from making, importing, using, or selling erythropoietin products protected by Amgen patents.