Along the lines of the issues discussed in our previous posts on when you don’t like a decision by a Patent Officer Examiner, and then when your petition to the PTO Commissioner is unsuccessful, what are a patent applicant's options after losing an Appeal before the Patent Trial & Appeal Board [the Board]?
One option is to request a Rehearing by the Board. Such a Rehearing is limited in that is sent back to the same panel that just rejected the Appeal. Further, the arguments which may be raised on rehearing are also somewhat limited. A Request for Rehearing must state with particularity the points believed to have been misapprehended or overlooked by the initially findings of the Board. Arguments not raised, and evidence not previously relied upon, are not permitted in the Request for Rehearing except to present a (1) new argument based upon a recent relevant decision of either the Board or a Federal Court, (2) new arguments responding to a new ground of rejection designated pursuant to (new grounds for rejection) are permitted, or (3) new arguments that the Board's decision contains an undesignated new ground of rejection.
These Rehearings are generally ruled in favor of the original holdings. If the board rules based on a new argument then you have the option of either reopening prosecution or requesting a rehearing within a time period of two months.
Another option is to challenge the Board under either 35 U.S.C. § 141 or § 145. Both of these statutes authorize a party with a disputed patent to bring suit in federal courts after being dissatisfied with the Board's decision. When bringing the suit, the applicant has two avenues, one is to seek direct review in the Federal Circuit Court of Appeals under § 141 using agency review. This is a technical appeal, in which the Federal Circuit reviews the Board's decision on the same administrative record that was before the PTO, and in which no new evidence can be introduced. The second avenue is by obtaining an indirect review in a federal district court under § 145 using court review and a substantial evidence standard to determine if an applicant is entitled to a patent under patent law.
Both of these options can be a seen as a good turn for those frustrated by initial attempts at obtaining protection for their inventions, since it allows for further due process. Unfortunately, for the applicants, the courts consider the PTO as an administrative agency, and when analyzing the cases, they hold deference to the PTO’s findings as an expert body, and will uphold the PTO’s decision if there is substantial evidence to support it, a relatively straightforward requirement for them.  The bar for either avenue by the applicant is typically high, but they do allow for any gross error or factual mistakes to be addressed appropriately. Additionally, if the plaintiff takes the indirect review under § 145, they are allowed to present to the district court evidence that they did not present to the PTO, since the idea is to allow a nonexpert judge to rule under the substantial evidence standard of the review.