How do intervening rights affect patent enforcement after inter partes reexamination?

Intervening rights can significantly affect patent enforcement after inter partes reexamination. When these rights apply, they limit the patent owner’s ability to enforce the amended or new claims against certain parties. The MPEP 2693 indicates that the effects are the same as those for reissued patents under 35 U.S.C. 252:

“The rights detailed in 35 U.S.C. 252 for reissue apply equally in reexamination and reissue situations.“

This means that:

• The patent owner cannot enforce amended or new claims against activities that occurred before the reexamination certificate was issued.
• Parties who were using the invention or made substantial preparations to use it before the reexamination certificate may have the right to continue their activities.
• The patent owner’s rights are essentially limited to enforcing the original claims as they existed before reexamination, for activities that occurred before the reexamination certificate was issued.

These limitations on enforcement help balance the interests of patent owners and those who relied on the original patent claims.

To learn more:

• intervening rights
• inter partes reexamination
• patent enforcement
• patent law