As some background, an inter partes review, or IPR, is an administrative post grant proceeding whereby a third party petitioner may attempt to invalidate one or more claims of an issued patent owned by a patentee, at the Patent Trial and Appeal Board (PTAB), based on evidence of published prior art. Where a third party is a named defendant in an action involving that issued patent, a time limitation of one year is imposed on the third party complainant to bring an IPR proceeding before the PTAB, from the time the initial complaint is served, pursuant to 35 U.S.C. 315(b) --
(b) Patent Owner’s Action.— An inter partes review may not be instituted if the petition requesting the proceeding is filed more than 1 year after the date on which the petitioner, real party in interest, or privy of the petitioner is served with a complaint alleging infringement of the patent. The time limitation set forth in the preceding sentence shall not apply to a request for joinder under subsection (c).
However, one exception to this time limitation, is a discretionary joinder under 35 U.S.C. 315(c) --
(c) Joinder - If the Director institutes an inter partes review, the Director, in his or her discretion, may join as a party to that inter partes review any person who properly files a petition under section 311 that the Director, after receiving a preliminary response under section 313 or the expiration of the time for filing such a response, determines warrants the institution of an inter partes review under section 314.
In this case, the PTAB instituted Apple's request for joinder, because it met with the burden of proving that it was entitled to relief, specifically, that Apple's petition relies on the same grounds as those instituted by the PTAB in the Mangrove IPR, and further: (i) the same schedule for various proceedings can be adopted, (ii) Apple is not advancing any new expert testimony, and thus, discovery will not be impacted by joinder, and (iii) joinder will not materially affect the range of issues needing to be addressed by the Board and by the parties in the joined proceedings.
For more on these cases visit http://ptabtrials.uspto.gov/ and type in the two Patent Nos. above.