Practitioners may not realize that the Patent Trial and Appeal Board (“PTAB”) has a rule expressly providing the ability to disqualify counsel. See 37 C.F.R. § 42.10(d) (“A panel of the Board may disqualify counsel for cause after notice and opportunity for hearing. A decision to disqualify is not final for the purposes of judicial review until certified by the Chief Administrative Patent Judge.”). That lack of knowledge is likely due to the fact that the PTAB has rarely even allowed a party to file such a motion, and has not yet disqualified counsel. This contrasts sharply with district court litigation since the beginning of AIA Post-grant proceedings in 2012, where a total of seventeen (17) identified decisions have resulted in counsel disqualification. The reasons for this trend are explained in more detail below, including a brief examination of the limited record of disqualification attempts at the PTAB.
First, unlike in the vast majority of district courts, a party must first ask for authorization to file a motion to disqualify in a PTAB proceeding before any such motion is filed. See 37 C.F.R. § 42.20(b). That gateway alone may serve to discourage parties from seeking disqualification, as may the fact that in its initial rules publication the PTAB made clear that “[m]otions to disqualify opposing counsel are disfavored because they cause delay and are sometimes abused.”
A recent decision on rehearing highlights the current situation with disqualification at the PTAB. In CommScope Tech, LLC v. Dali Wireless Inc., the PTAB denied Petitioner’s rehearing request of the panel’s denial to disqualify counsel for Patent Owner. IPR2018-00571, Paper 25 (July 15, 2018). Among the arguments raised were that Patent Owner’s counsel had represented Petitioner in the prosecution of a family of patents – where a member of that family was raised in the Petition as prior art. IPR2018-00571, Paper 18 (May 8, 2018) at 2. Petitioner also argued that Patent Owner had falsely claimed the existence of an ethical wall between attorneys of the firm that had represented Petitioner in prosecution matters and those that were involved in the instant inter partes review proceeding. Id. at 2-3.
As to the notion of an ethical wall, the panel dispensed with that question by stating “[i]f such an ethical wall was necessary or effective, it nevertheless would have been breached when one of those lawyers was included as backup counsel here. Additionally, Rule 110 of the USPTO Rules of Professional Conduct imputes the conflicts of interest of any practitioner in a firm to all the practitioners in the firm, with certain exceptions not relevant in this case.” Id. at 3-4. As to the past representation itself, the PTAB noted that “the moving party bears a heavy burden to show disqualification is necessary.” Id. at 5 (citing Anderson v. Eppstein, 59 U.S.P.Q.2d 1280, 1286 (BPAI 2001) (informative)). As to the analysis, “Rule 109(a) precludes counsel from representing a person in ‘the same or a substantially related matter in which that person’s interests are materially adverse to the interests of [a] former client.’” Id.
The panel ultimately concluded that they were “not convinced that the subject matter of the prior representation of CommScope by Kilpatrick Townsend is essentially the same as, or involves the same transaction or legal dispute as in this proceeding.” Id. The panel supported its reasoning by stating “[w]e have been provided with no indication that [our] determinations,” i.e. institution of trial, issuance of final written decision on original or amended claims, “were involved in the matters in which Kilpatrick Townsend represented CommScope and see no reason CommScope’s confidential information would be relevant to this matter.” Id. As to the prior art reference included in the Petition, it was provided “in the alternative with five other references, for its disclosure of what the Petition asserts is a ‘well-known network topology’ as ‘disclosed in many references.’” Id. Ultimately, the panel concluded that “[w]ith respect to the representation regarding the prosecution of the ’091 patent family, and the appearance of the ’091 patent in the Petition, we also do not find these to involve the same transaction or legal dispute, or see how confidential information learned during such prosecution would be relevant to what the ’091 patent, as issued, teaches to an artisan of ordinary skill.” Id. at 6. Thus, ending the inquiry, and resulting in a denial of Petitioner’s motion to disqualify.
Beyond the decision in CommScope, the PTAB has only authorized the filing of a disqualification motion in a single other instance. See SAP America, Inc. v. Lakshmi Arunachalam, CBM2016-00081, Paper 12, (Nov. 18, 2016) at 3-6. In the merits decision, the panel declined to disqualify counsel based on a number of arguments – including those previously dismissed by the Federal Circuit in earlier appeals. Id. The PTAB has otherwise denied authorization to file a disqualification motion in 4 other instances starting in April of 2013.
Thus, while Practitioners should be mindful that motions for disqualification are within their PTAB toolkit, they should consider that tool like many others at the PTAB that have district court analogs – with caution and reference to prior PTAB practice.
 77 Fed. Reg. 48630 (Aug. 14, 2012)
 Notably, the Anderson decision is in the context of interference practice where a petition to disqualify was denied.
 See ScentAir Tech., Inc. v. Prolitec, Inc., IPR2013-00179, Paper 9 (April 16, 2013) (covering two IPRs); TD Ameritrade Holding Corp., et al. v. Trading Tech. Int’l, Inc., CBM2014-00131, Paper 10 (July 24, 2014) (covering five CBMs); John Crane Prod. Sol., Inc. et al. v. Finalrod IP, LLC, IPR2016-00521 (March 29, 2016); UPL Ltd. v. Agrofresh, IPR2017-01919, Paper 35 (June 13, 2018).