October 17, 2014 Last month, the Patent Trial and Appeal Board (PTAB or Board) interpreted the IPR joinder provision, 35 U.S.C. § 315(c), to preclude joinder requests by an existing party to an ongoing proceeding.  (Target Corp. v. Destination Maternity Corp., IPR2014-00508 and IPR2014-00509.)  In these recent decisions, the Board decided that § 315(c) requires “party joinder” and…