What is the primary difference between appealing under 35 U.S.C. §141 and §145?

The primary difference between appealing under 35 U.S.C. §141 and §145 lies in the ability to introduce new evidence. When appealing under §145, a party can present new evidence that was not part of the original administrative record. This means that the appeal to the federal district court can include additional information that may influence the outcome of the appeal, potentially altering the case's course compared to what was determined by the Patent Trial and Appeal Board (PTAB).

In contrast, §141 only allows the appeal to be based on the existing record created during the proceedings before the PTAB, meaning that no new evidence can be brought forward in that type of appeal. This distinction is crucial as it affects the strategy and potential outcomes of the appeals process.

The other options do not accurately capture the main distinguishing factor. The limitation on new evidence in §141 directly impacts how each appeal is navigated and the opportunities for both parties to present their cases. Understanding this difference is essential for anyone engaged in patent disputes and appeals.