How does the best mode requirement apply in reexamination proceedings?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

The application of the best mode requirement in reexamination proceedings is an important consideration. MPEP 2280 provides guidance on this matter:

“The best mode requirement is not applicable to reexamination proceedings filed on applications with an effective filing date on or after September 16, 2012, the effective date of the AIA. In addition, for reexamination proceedings filed on applications with an effective filing date before September 16, 2012, failure to disclose the best mode is not a proper basis on which to reject claims. However, in a reexamination proceeding of such an earlier application, best mode issues may still be raised as to any newly-added or amended claims.”

This means that while best mode is not a basis for rejecting claims in most reexamination proceedings, it may still be relevant for certain applications filed before September 16, 2012, particularly concerning new or amended claims. Patent owners and practitioners should be aware of this distinction when dealing with reexamination proceedings involving pre-AIA applications.