The Opposition Division of the European Patent Office (EPO; Munich) has upheld Cambridge Antibody Technology's (CAT; Melbourn, UK) core “McCafferty” European patent (EP 0589877) without amendments following a challenge from rivals Dyax (Cambridge, MA), BioInvent (Lund, Sweden), and Morphosys (Munich); the patent covers methods for making single-chain variable-region fragments on certain bacteriophages. The legal path is now cleared for the recommencement of CAT's feud with Morphosys; proceedings that CAT had taken out against Morphosys in the Munich District Court for infringement of both the McCafferty patent and a broader phage display patent known as “Winter II” had been suspended, pending the EPO Opposition Division's decision. Morphosys Chief Scientific Officer Thomas von Rüden insists that the EPO decision does not affect its ability to develop and use its HuCAL library even though HuCAL does involve the use of phage in screening for appropriate antibody regions. However, CAT CEO Dave Chiswell is reportedly equally insistent that its rivals could not display single-chain variable-region fragments without infringing the CAT patent.