In a significant development, the European Patent Office (EPO) has revoked Salix Pharmaceuticals’ European patent for the antibiotic rifaximin. In decision T 0162/22, the EPO Board of Appeal confirmed the revocation of European Patent EP 2 252 148 following the withdrawal of all remaining claim requests after opposition proceedings were initiated by eight opponents.
The patent had covered the use of rifaximin for treating hepatic encephalopathy, among other applications. However, Salix withdrew all claim requests during appeal proceedings, resulting in the complete revocation of the patent.
This case highlights the importance of maintaining a valid set of claims throughout opposition and appeal procedures. Without such a claim set, the EPO is obliged to revoke the patent.
