What are the limitations on new rejections in ex parte 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.

In ex parte reexamination, there are specific limitations on introducing new rejections:

• Pre-AIA 35 U.S.C. 303(a) and 37 CFR 1.906(c) restrict new rejections to those based on patents or printed publications.
• New rejections cannot be based on issues like 35 U.S.C. 112 or public use.
• The MPEP 2258 states: “Any rejection which relies upon any combination of references in the reexamination proceeding must be a substantial new question of patentability.”

These limitations ensure that the reexamination focuses on prior art issues and maintains a scope consistent with the original examination.