Inter partes review (“IPR”) is one of several post-grant procedures created by the Leahy Smith America Invents Act (“AIA”).  An IPR provides a mechanism for challenging the patentability of one or more claims of an issued patent through an administrative “trial” conducted by three Administrative Patent Judges from the United States Patent and Trademark Office’s Patent Trial and Appeal Board (“PTAB” or “Board”).  An IPR is available for any patent regardless of the issue date, but for patents examined under the AIA (those filed on or after March 16, 2013), an IPR petition may not be filed until nine months after the patent issues.  Additionally, if a petition for a post-grant review (“PGR”) has been instituted for the patent, the PGR must be concluded before an IPR petition can be filed.

IPRs were intended to provide a faster, more efficient, and less expensive means for challenging patents compared to traditional litigation.  The potential benefits of IPR over federal court litigation include:  a lower burden of proof, the absence of a presumption of validity, and a broader standard for claim construction.  An IPR may also be available earlier than litigation on biosimilar products (because it is not necessary to wait until a BLA has been filed and accepted for review by FDA before filing an IPR petition), and an IPR may provide faster resolution than litigation because of the short statutory deadlines imposed on the proceeding.

On the other hand, the grounds that can be asserted in an IPR are limited to challenges under 35 U.S.C. §§ 102 and 103 (anticipation and obviousness) based on patents and printed publications.  Another difference is that although discovery is permitted in an IPR, the scope of discovery is much narrower than in district court litigation.  Also, the direct testimony of expert witnesses is submitted in form of written declarations and cross-examination of experts is conducted by deposition.  Therefore, the only live testimony presented to the Board is generally attorney argument at the oral hearing, which is often limited to an hour or less per side (rather than the multi-day or multi-week trials held by district courts).  One should also be aware of the potential for estoppel under 35 U.S.C. § 315(e), as discussed in a post on RFEM’s PTAB website here.  Finally, each individual petition for IPR may only address one patent, so challenges to more than one patent require multiple IPR petitions.  Thus, IPRs may be a particularly useful alternative for biosimilar product manufacturers and developers to challenge individual patents or a small set of key patents outside of BPCIA litigation.

The preliminary portion of an IPR proceeding begins with the filing of a petition by a third party.  The patent owner has three months to file a preliminary response, and the PTAB will make a determination on whether to “institute” review within six months of the filing date of the petition.  The Board will institute an IPR if the petitioner has demonstrated “a reasonable likelihood that it will prevail with respect to at least one of the challenged claims.”  If the IPR is instituted, the “trial” portion of the proceeding will begin, and the Board will issue a final written decision within one year of the institution decision.  The one year statutory deadline may be extended by up to six months for good cause shown.

Petitions for IPR have been filed on many patents related to proposed biosimilar products.  A complete summary of IPR proceedings for patents related to proposed biosimilar products is provided in RFEM’s Biosimilars IPR Dashboard.

RFEM has an extensive PTAB practice.  For more information about our practice and other useful information about recent decisions from the PTAB, visit our PTAB site at