Proving 'Prior Art' At The PTAB

The new patent trials before the Patent Trial and Appeal Board ("PTAB") at the U.S. Patent Office have become a popular forum for challenging U.S. patent claims. These new trials went into effect just 3 years ago and since then almost 4000 petitions have been filed.1 And almost 7500 claims have been canceled.2 To challenge claims, a Petitioner files a petition and identifies grounds of unpatentability that can include challenges based on prior art patents or publications.3 In addition to presenting arguments and positions to show how the prior art render the challenged claims unpatentable, a Petitioner must also provide enough evidence to show that the documents relied are indeed publically available prior art.4

All evidence, including evidence tending to show public availability, must satisfy the U.S. Federal Rules of Evidence.5 For patents and patent publications this likely presents little difficulty. Though the Petitioner must prove that the patent or patent publication predates the effective filing date of the challenged patent, the date on the face of the patent or patent publication is generally sufficient.

Newspaper articles, advertisements, journal papers, conference presentations, and other non-patent literature may require a further showing. Non-patent literature documents can, and often are, relied on as prior art. Under U.S. patent law, a document, including non-patent literature is prior art if it was:

"disseminated or otherwise made accessible to persons interested and ordinarily skilled in the subject matter to which the [document] relates prior to the critical date."6 The proponent of a document must present sufficient evidence to show dissemination or availability.7 Proving a document was published and publicly available at a given time may require additional evidence.

For example, while many non-patent literature documents include a date, relying on the date alone to show a prior art date often implicates hearsay―a statement made out of court and relied upon to show the truth of the statement.8 While, hearsay is a common type of evidence, it is presumptively inadmissible in PTAB proceedings because of the common law view that such statements are untrustworthy.9 Although the dates on U.S. Patents and patent publications (as well as many non-U.S. patent documents) are technically hearsay, the dates and underlying documents, often fall into clear hearsay exceptions, such as the public records exception, where trustworthiness is not an issue.10

In contrast, however, the publication date of non-patent literature like journal articles, user manuals, corporate brochures, and other publications, which may be in the form of a date stamps,11 affidavits and declarations,12 or corroborating advertisements,13 may be more difficult. If a Petitioner cannot overcome a hearsay challenge, the evidence may be inadmissible, and the Petitioner may not be able to show that a particular reference is prior art. Such a setback could be fatal.14 And recent PTAB decisions highlight the importance of this interplay between hearsay and the Petitioner's requirement to sufficiently establish a prior art date for a reference.

Background

The Federal Rules of Evidence apply in inter partes review and covered business method review proceedings.15 The rules, which also apply in district court, allow a party to challenge its opponent's evidence. Relevance,16 authenticity,17 and privilege18 are all grounds for challenge.

Generally, the evidentiary rules suggest that relevant evidence should be admitted.19 In contrast, hearsay evidence, including both oral and written statements, is generally not admissible, even when it is relevant to a proceeding.20 Hearsay is excluded because it is generally believed to be unreliable; when a witness is not subject to cross-examination or is not under oath, we are less inclined to trust the statement. There are, however, several hearsay exceptions21 and exclusions22 for evidence that should be admitted because it is otherwise sufficiently reliable. Many of these exceptions and exclusions are pertinent to establishing a prior art date and Patent Owners alike should be well versed in how they apply to non-patent literature documents.

There are two types of hearsay exceptions―specific exceptions that have been established over time and generally adopted. Rule 803 provides a list of specific types of statements that are admissible although the statement is otherwise hearsay. Rule 803 exceptions apply regardless of whether the declarant (whoever issued the original statement) is available.23 Rule 804 applies only when the declarant is unavailable, something the proponent of the evidence must show in order to rely on an 804 exception.24 Rule 807 sets forth a "residual exception," which allows hearsay evidence to be admitted even if it is not within a specific exception if:

the statement has equivalent circumstantial guarantees of trustworthiness; it is offered as evidence of a material fact; it is more probative on the point for which it is offered than any other evidence that the proponent can obtain through reasonable efforts; and admitting it will best serve the purposes of these rules and the interests of justice. In addition, Rule 801 excludes several types of statement that would otherwise be "hearsay," including statements made by an opposing party.25

An important distinction is that an out of court statement is only hearsay if it is offered for its truth. A statement t...