Intellectual Property Report

The Dangers of Secret Prior Art

Brianna Potter

It is well-established that the availability of a prior art reference is dependent on the "effective filing date" of a patent or patent application. Any practitioner seeking to invalidate a patent knows that the ideal references used both for prior art and for demonstrating the knowledge of a POSITA will have been made public before the effective filing date of the patent in question.

However, there is yet a question of whether references filed before but published after a patent's priority date can be used to show what would be known by a POSITA at the time of invention. In a recent decision in the Northern District of West Virginia, Chief Judge Thomas discussed exactly this issue when denying a Motion for Preliminary Injunction.