Can an examiner issue a new rejection of previously patentable claims in inter partes reexamination?

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.

Yes, an examiner can issue a new rejection of previously patentable claims in inter partes reexamination under certain circumstances. The MPEP states:

“It should be noted that even in a situation where there has been no patent owner response, the examiner is always free to issue a supplemental Office action providing a new rejection of claims previously found patentable, where new information comes to the attention of the examiner warranting the new rejection.”

This provision allows examiners to address new information that may affect the patentability of claims, ensuring a thorough examination process. However, such actions are typically not made as an Action Closing Prosecution (ACP).