How do terminal disclaimers affect patent expiration dates?

Terminal disclaimers can affect the expiration date of a patent by limiting its term to that of an earlier-issued patent. The MPEP explains, If the disclaimer disclaims the terminal portion of the term of the patent which would extend beyond the expiration date of an earlier issued patent, then the expiration date of the earlier issued patent determines the expiration date of the patent subject to the terminal disclaimer. However, the exact impact depends on the language of the disclaimer and may require examination of the patent file history. It’s important to note that a patent term extension under 35 U.S.C. 156 can still be applied to a patent subject to a terminal disclaimer.

To learn more:

• terminal disclaimer
• patent expiration
• patent term extension