GlaxoSmithKline hit by US patent ruling on Augmentin antibiotic

GlaxoSmithKline has lost a US court case at which it was defendingpatents to its blockbuster antibiotic Augmentin (amoxicillin/clavulanate), raising the threat of generic competition as early as 2003. The patents under dispute in the case were not due to expire until 2017, but the decision to find them invalid means that Augmentin will now lose US patent protection on December 24 of this year.

This is the second unfavorable patent ruling for the UK company this month, having lost the first round in a court case relating to extended-release bupropion-based products, brought by Andrx Corp (Marketletter March 11).

The latest verdict does not come as a complete surprise, however, given that GSK lost the first round of the dispute, brought by generics company Teva Pharmaceuticals, at the end of last year (Marketletter January 1 & 7). At that time, the court upheld GSK's 2002 patents, but found that another, due to expire in 2018, was invalid. GSK said it hoped to appeal the latest ruling, and noted that a decision on this would normally take 12 to 18 months from its filing. Rivals would be able to launch generic copies of Augmentin after the 2002 patent expiry, but would lay themselves open to significant damages should GSK win its appeal.