What does the term "reasonable likelihood" signify in the context of initiating an inter partes review?

In the context of initiating an inter partes review (IPR), the term "reasonable likelihood" signifies the expectation that the petitioner will prevail on at least one of the claims challenged in their petition. This standard requires that the petitioner present sufficient evidence and arguments that suggest a plausible basis for believing that at least one of the claims in question is unpatentable.

The focus of "reasonable likelihood" is not simply on whether claims are likely to be rejected overall or establishing unpatentability across all challenges; rather, it is specifically aimed at the potential for the petitioner to succeed with at least one of the claims that they are asserting against the patent. This threshold is a critical part of the IPR process, as it serves to filter out petitions that do not present a serious challenge to the validity of a patent before the Patent Trial and Appeal Board (PTAB) agrees to review.

While options suggesting likelihood of claim rejection or probability of successful litigation touch on related themes, they do not accurately encapsulate the specific focus of "reasonable likelihood" in the IPR context, which is about the potential to win on the substantive challenges presented rather than the broader outcomes related to patent validity or litigation success.