Once a petition for inter partes review is filed, the patent owner has 3 months under the PTO rules (Rule 42-107) to file an optional preliminary response –  before the PTAB decides whether or not to institute proceedings.  Considering that the petitioner has typically spent many months preparing the petition, including preparing detailed claim charts and expert declarant testimony, the patent owner is usually at a disadvantage in mounting a rapid rebuttal.

Additionally, pursuant to Rule 42.107 (c), the patent owner cannot introduce any expert opinions of its own in its preliminary response.  Rule 42.107 (c) states that “the preliminary response shall not present any new testimony evidence beyond that already of record.”

Moreover, the PTO’s projection that 90% of petitions will be granted (which appears to have been right on the mark), suggests that a preliminary response will often be a futile attempt at quashing the proceedings and can even hurt the patent owner (since it can provide the petitioner with an early insight into the patent owner’s defense strategy).

Nonetheless, it appears that the overwhelming majority of patent owners facing this dilemma have chosen to file a preliminary response.  Why?  Apart from the obvious reason that lawyers rarely forego an opportunity to plead their case, there are several reasons to file a preliminary response.

One reason is when the petition is weak, a preliminary response may dispose of the case entirely.  For example, if the petitioner has failed to address an element of a claim, asserts a very unreasonable claim construction or incorrectly identifies a reference as prior art, a response may bring this error into stark relief.

Another reason would be to narrow the issues.  For example, several Board decisions have denied redundant or cumulative combinations of references.  A preliminary response can highlight a petitioner’s failure to distinguish various references from each other and thus set the stage for dismissal of many of the petitioner’s alternative grounds for invalidity.

The Patent Owner can also use the preliminary response to disclaim some of the claims under attack, again narrowing the issues, and possibly gaining credibility in the eyes of the Board when defending the remaining claims.  Amendments, however, are not permitted at this stage.

Whether or not the patent owner chooses to engage on the merits prior to the institution of proceedings, a response with the mandatory notice items (which include identification of real party in interest, a listing of related proceedings that would affect or be affected by a decision, identification of lead and back-up counsel and service information) is required within 21 days under 37 CFR 42.8.