Patent Bar Practice Exam

The consequence for the loser of an interference in the Patent and Trademark Office (PTO) regarding their claims of inventorship is that they are estopped from claiming they were the first to invent in Federal District Court. This principle of estoppel arises because the interference proceeding serves as a definitive examination of inventorship and priority between competing claims.

When the PTO resolves the interference, it effectively determines which party is entitled to the patent based on the evidence presented about who was the first to invent. By losing the interference, the failing party cannot later go to Federal District Court and argue that they were indeed the first inventor, as this would contradict the conclusion reached during the interference. Thus, their loss in the interference proceeding is binding on them, preventing them from raising the same arguments in a different venue regarding their inventorship rights.

This principle reinforces the finality of the PTO's decisions in determining priority and helps maintain orderly proceedings in patent law by discouraging parties from continually relitigating issues resolved by the PTO.