Let’s say you are litigating an inter partes review before the Patent Trial and Appeal Board (PTAB). Should you be worried your communications with a testifying expert are discoverable?

Although the PTAB has not directly addressed the question, the Federal Rules of Civil Procedure dictate that such communications are protected. Of course, that rule applies only to federal district court litigation. How would it play in the PTAB?


In 2010, Federal Rule of Civil Procedure 26(b)(4)(C) was amended to protect “communications between the party’s attorney and any witness required to provide [a testifying expert report], regardless of the form of the communication,” subject to relatively limited exceptions. The rules committee proposing the amendment stated it was “designed to protect counsel’s work product and ensure that lawyers may interact with retained experts without fear of exposing those communications to searching discovery.”

With the enactment of the America Invents Act (AIA), a party may challenge the validity of a patent before the PTAB, such as in an inter partes review (IPR). As IPRs routinely involve the presentation of expert witness testimony — sometimes using the same experts as in co-pending litigations — some practitioners have grown concerned over whether attorney-expert communications constitute protected work product before the PTAB.

Although Rule 26 does not apply in proceedings before the PTAB, the policy underlying the rule is instructive in understanding the scope of work product protection in contested matters before the PTAB.

Decisions providing insight on attorney-expert communications

Inquiry into attorney-expert communications may arise in three possible ways: during written discovery in the PTAB, during the cross-examination of the expert in the PTAB, and during discovery in any later or co-pending district court litigation.

During discovery. On the first point, a party probably cannot compel production of attorney-expert communications through discovery in a PTAB proceeding. Discovery is limited in all AIA post-grant procedures. Routine discovery in an IPR provides for production of any exhibit cited in a paper or testimony; the cross-examination of the other side’s declarants; and relevant information inconsistent with a position advanced during the proceeding. Per Garmin v. Cuozzo, Parties may request additional discovery, but it is only authorized if such discovery is “in the interests of justice.” 

Although there is minimal precedent addressing how the PTAB will treat discovery requests for production of attorney-expert communications, at least one recent decision indicates that the narrow scope of discovery in IPRs does not allow for it. In Corning Inc. v. DSM IP Assets B.V., a patent owner moved for discovery requesting the petitioner produce “a privilege log.” The board held the production of a privilege log was unnecessary as it was not “in the interests of justice.” If the PTAB would not permit the production of a privilege log — which would allow for only the identification of any attorney-client privileged or work product materials — it is hard to conceive how the PTAB would justify production of the underlying documents “in the interests of justice.”

It is also well established that if there is an adversarial proceeding before the Patent Office, attorney work product is protected. As IPRs, covered business method reviews, and post-grant reviews are all adversarial proceedings, work product should be equally protected during discovery in the PTAB.

During cross-examination. The PTAB is probably unlikely to permit inquiry into attorney-expert communications during a deposition. In the interference proceeding Pevarello v. Lan, the Board of Patent Appeals and Interferences (BPAI) issued a memorandum opinion “counsel[ing] against any attempt to inquire on cross-examination into how direct testimony declarations came to be prepared.” The PTAB probably will continue this policy of protecting expert communications with attorneys, including discovery into drafts of expert reports.

During later litigation. Finally, in light of the new, stricter Rule 26 governing disclosures relating to expert witnesses, the district courts probably will allow as much protection over attorney-expert communications that occur in a PTAB proceeding as they would over such discussions in district court litigation.


Based on the limited discovery allowed AIA post-grant procedures, the BPAI’s past decisions, and initial decisions from the PTAB on discovery, it seems likely that the PTAB will consider attorney-expert communications, including draft expert reports, protected work product.