Amgen has won another round in its legal battle in the USA to protect its anaemia drugs Aranesp and Epogen and prevent Roche from launching its rival product Mircera.

The US District Court in Boston has upheld an earlier jury verdict which had stated that Roche’s pegylated-erythropoietin drug Mircera (methoxy polyethylene glycol-epoetin beta) infringes 10 claims of four of Amgen’s EPO patents. The US biotechnology firm’s own erythropoiesis-stimulating agents, Epogen (epoetin alfa) and Aranesp (darbepoetin alfa), are major earners, accounting for more than 40% (around $6.3 billion) of Amgen’s revenues last year.

Roche’s drug was approved by the US Food and Drug Administration last November but the company has been unable to launch it there because the court in Boston had previously entered a preliminary injunction preventing the Swiss drugmaker from selling Mircera, a decision which the latter has appealed.

However this latest ruling has now seen the court rule that Amgen is entitled to a permanent injunction prohibiting Roche from selling Mircera. The ruling stated that “failure to enter a permanent injunction…would risk undermining the incentives for innovation that have produced, and hopefully will continue to produce, medical advances that extend and enhance the value of life”.

As such, the court “concludes that the public interest will not be disserved by a permanent injunction”. The latter will be entered once Roche’s appeal of the preliminary injunction is resolved; a hearing has been scheduled for next week.

Amgen was unsurprisingly cock-a-hoop and general counsel for the firm, David Scott, said that the ruling recognises that the firm is entitled to a permanent injunction “and reaffirms the infringement and validity of our patents”. For its part, Roche is assessing how this latest opinion impacts its current appeal, however it looks as though it will have to concentrate on the European market where Mircera was launched last year after being approved in July.

In a separate decision, the Boston court upheld the validity of an Amgen patent that claims pharmaceutical compositions of human EPO and entered a permanent injunction prohibiting Shire 's Transkaryotic Therapies and Sanofi-Aventis from marketing their gene-activated Dynepo (epoetin delta). Shire announced in August that it had stopped selling Dynepo as it is “an uneconomic product".