Which statement about the inter partes review process is correct?

The inter partes review (IPR) process is designed specifically for challenging the validity of one or more claims in a patent after it has been granted. A key feature of IPR is that it is limited in scope to considering only certain types of evidence, specifically patents and printed publications. This restriction is in place to streamline the review process and focus on prior art that is most relevant to patent validity.

The process allows for parties to challenge patent claims based on prior art that may invalidate those claims, and by narrowing the evidence to patents and printed publications, the IPR process remains efficient and effective in addressing validity concerns. This focus is also why the other options do not hold true; for instance, not all evidence is admissible in this context, claims under review have defined limits relating to prior art, and the IPR process is specifically initiated after a patent has been issued, not before.

This structure and limitation are essential for maintaining the integrity and efficiency of the patent system, allowing for a fair and focused examination of patent validity without the extensive breadth that could complicate and prolong the review.