As we reported in January 2015, questions concerning partial priority and so-called poisonous divisionals were referred to the EPO 's Enlarged Board of Appeal following appeal T 557/13 (relating to European patent application 98203458.9). The long-awaited written decision in T 557/13 has now issued, and can be found here.
Five questions have been referred to the Enlarged Board of Appeal, and these are set out at page 60 of the decision. Questions 1 to 4 relate to partial priority, and in particular seek clarity on how entitlement to partial priority should be assessed. Question 5 relates to so-called poisonous divisionals, and in particular whether a parent application or divisional application of a European patent application can be citable under Article 54(3) EPC against that European patent application.
Welcome clarity on these issues should be provided when the Enlarged Board of Appeal answer the questions in due course. In view of the importance of the matter, we would expect the questions to be answered within the next two years, and perhaps even earlier. In the meantime, those interested in the current position can read our briefing here.