Suppose a patent owner files suit and the defendant wants to file an AIA post-grant proceeding to challenge the validity of the patent.  Suppose further that the post-grant challenge is an inter partes review (IPR) filed by the defendant within a year of service of process of the complaint.  If the IPR petition only alleges grounds of invalidity for certain claims, and the patent owner later amends its complaint to add more claims to the action after the one year period of 35 U.S.C. § 315(b) that were not the subject of the original IPR petition, is the petitioner forced to use ex parte reexamination to challenge the newly added claims?  No.  If the petitioner can apply for joinder under 37 C.F.R. § 42.122(b), the PTAB may consider the second petition and join it with the first timely filed petition, even if it is beyond the one year period of 35 U.S.C. § 315(b).  In Microsoft v. Proxyconn, IPR2013- 00109, the Board allowed joinder, stating:

As is apparent from the statute, a request for joinder affects certain deadlines under the AIA. Normally, a petition for inter partes review filed more than one year after the petitioner (or the petitioner’s real party-in interest or privy) is served with a complaint alleging infringement of the patent is barred. 35 U.S.C. § 315(b), as amended; 37 C.F.R. § 42.101(b). However, the one-year time bar does not apply to a request for joinder. 35 U.S.C. § 315(b)(final sentence); 37 C.F.R. § 42.122(b). This is an important consideration here, because Microsoft was served with a complaint asserting infringement of the ʼ717 patent more than a year before filing the second Petition. Pet. 1. Thus, absent joinder of this proceeding with IPR2012-00026, the second Petition would be barred. Moreover, in the case of joinder, the one-year time requirement for issuing a final determination in an inter partes review may be adjusted. 35 U.S.C. § 316(a)(11), as amended.

This is good news for that Petitioner, since it allowed for adjustment of the petition grounds via joinder to match claims added to a parallel litigation after the one year period of 35 U.S.C. § 315(b).

A motion for joinder was very recently filed in IPR2013-00250 (Ariosa Diagnostics v. Isis Innovation), seeking to join the IPR2013-00250 proceeding with the trial already instituted in IPR2012-00022.  The motion for joinder cites the rule excerpt:

§ 42.122 Multiple proceedings and Joinder.

(b) Request for Joinder. Joinder may be requested by a patent owner or petitioner. Any request for joinder must be filed, as a motion under § 42.22, no later than one month after the institution date of any inter partes review for which joinder is requested. The time period set forth in § 42.101(b) shall not apply when the petition is accompanied by a request for joinder.

It will be interesting to see how the Board considers joinder under the various fact patterns that are inevitable in practice.