Can a losing party in a patent interference pursue claims in a continuing application?

A losing party in a patent interference may pursue claims in a continuing application, but with significant limitations due to estoppel. According to MPEP 2308.03, the following restrictions apply:

• Claims that would have been anticipated or rendered obvious by the subject matter of the lost count are barred due to estoppel on the merits.
• Claims that could have been pursued or amended during the interference, but were not, are barred due to procedural estoppel.

For example, if an applicant lost on priority for subject matter X, they cannot file a continuing application with a claim to X or a claim that would be obvious in view of X. Additionally, if the applicant could have amended a claim during the interference but did not, they cannot later amend that claim in a continuing application to overcome the grounds for unpatentability established in the interference.

To learn more:

• patent interference
• continuing application
• estoppel
• MPEP