On June 5, 2013, the Patent Trial and Appeal Board (“Board”) entered an order denying a motion seeking to join two additional parties, as petitioners and real parties-in-interest, that were not parties to the inter partes review (“IPR”) petition as originally filed (Case CBM2013-00014; Patent 6.625,682). According to the Board, there is no support in the AIA statute or rules for joining parties and instead, Congress provided for joinder of proceedings under § 325(c). Under the Board’s rationale, the statutory framework provides for “the situation where a party might wish to join an additional petition with an already instituted proceeding, and provides a way to do so.” To join additional parties to an existing proceeding, the Board indicates is a matter of first impression. Interestingly, by not having parties join an IPR, some courts weigh this factor into their determination of whether to grant a stay pending an IPR.

For example, in Semiconductor Energy Lab Co., Ltd. v. Chimei Innolux Corp., the Central District Court of California explained that “the estoppel effect of inter partes review carries less weight when there are several defendants that are not parties to, and thus are not bound by, the estoppel effects of the proceeding.” No. SACV 12-0021 JST (JPRx), 2012 WL 7170593, at *3 (C.D. Cal. Dec. 19, 2012). And because, the defendants in Semiconductor who did not file the IPR petition agreed to be bound by the estoppel provisions of the IPR proceeding, the court gave the estoppel full weight in its determination. In other instances, the estoppel effect has not been give full weight because certain defendants were not parties to the IPR. Pi-Net Int’l, Inc. v. The Hertz Corp., et al., CV 12-10012 PSG (JEMx), CV 12-4270 PSG (JEMx), CV 12-4036 PSG (JEMx) (C.D. Cal. June 5, 2013).

Albeit whether all defendants are parties to the IPR proceeding is one of the factors courts evaluate in determining whether to grant a stay pending an IPR, it will be interesting to see how this plays out over time and how broad of an application occurs.