LONDON Pfizer suffered a setback in Britain on Thursday when the Court of Appeal in London ruled against it in a patent case over the use of its $5 billion-a-year drug Lyrica for pain relief.
Pfizer said it was disappointed by the decision and would seek a further appeal.
Lyrica, known generically as pregabalin, was originally developed for epilepsy. However, further research showed it could also help patients suffering from neuropathic pain and most prescriptions are now written for pain.
While the original patent on pregabalin has expired, Pfizer was awarded a secondary patent covering pain, valid until July 2017, and the U.S. drugmaker had been fighting to protect this lucrative section of the market.
The expiry of the basic patent allowed generic drugmakers including Actavis, now renamed Allergan, to launch cut-price versions of the medicine, which carried a "skinny label" limiting their use to epilepsy and general anxiety disorder.
But Pfizer still sued, arguing it was inevitable that the copycat versions would be dispensed for pain as well as other conditions.
The court of appeal ruling endorsed an initial 2015 verdict that generic companies had not infringed Pfizer's secondary patent and its patent claims directed generally to pain and neuropathic pain were invalid.
(Reporting by Ben Hirschler; Editing by Tom Bergin/Ruth Pitchford)