A number of biosimilar makers have turned to inter partes review (IPR) proceedings in order to litigate the validity of patents that cover their proposed products prior to submission of their biosimilar applications to FDA.  Prior to the submission of a biosimilar application, a challenge to patent validity in district court is typically premature.  As the Federal Circuit recently explained, it has never “found a case or controversy when the only activity that would create exposure to potential infringement liability was a future activity requiring an FDA approval that had not yet been sought.” Since IPRs, unlike district court proceedings, do not require a case or controversy, they allow potential biosimilar applicants to resolve potential patent disputes long prior to being able to litigate these disputes in district court and to potentially avoid the patent dispute resolution procedures of the Biologics Price Competition and Innovation Act (BPCIA) of 2009 entirely.

A number of biosimilar makers have filed IPRs challenging the validity of innovator patents prior to submitting their biosimilar applications to FDA.  The first such example is Hospira’s challenge to a patent covering a dosing regimen for administering erythropoietin (EPO).  Hospira sells a biosimilar version of EPO in Europe and is seeking approval for its biosimilar version of EPO in the U.S.  The innovator product is a blockbuster recombinant protein that is sold as Epogen by Amgen and Procrit by Janssen.

Hospira filed its IPR (IPR2013-00365) on June 19, 2013, about 18 months prior to submitting its biosimilar application to FDA seeking approval to market its proposed biosimilar version of EPO.  It typically takes 18 months from the filing of an IPR petition to a final written decision from the Patent Trial and Appeal Board (PTAB) on the merits.  Here, the patent owner disclaimed the claims challenged in Hospira’s petition, mooting the IPR.  As a result, Hospira obtained certainty with respect to the dosing regimen patent well before it submitted its biosimilar application to FDA on December 16, 2014 and well before it could litigate the validity of this patent in district court.  However, given the timing of Hospira’s IPR petition, even if an IPR had been instituted, there was sufficient time to obtain a final decision from the PTAB on the validity of the patent prior to Hospira’s submission of its biosimilar application to FDA.

Boehringer Ingelheim recently filed IPR petitions (IPR2015-00415, 417 and 418) challenging three patents to methods of using Biogen and Genentech’s blockbuster antibody product, Rituxan.  Boehringer is developing a biosimilar of Rituxan.  Rituxan is indicated for treating certain patients with rheumatoid arthritis that did not respond to other therapy and non-Hodgkin’s lymphoma, among other indications.

The patents are to a combination therapy of using the Rituxan antibody and methotrexate to treat rheumatoid arthritis, a method for treating rheumatoid arthritis in certain patients that do not respond to other therapy according to a specific dosing regimen and a method for treating low grade B-cell non-Hodgkin’s lymphoma using chemotherapy followed by administration of the antibody according to a specific regimen.  All three patents do not expire until 2020 or later.

Boehringer filed its IPR petitions in December 2014, long prior to submission of its regulatory application to FDA.  Boehringer argues that all three patents are either anticipated and/or obvious.  Biogen and Genentech submitted their patent owner preliminary responses in April 2015, contending that Boehringer’s IPR petitions are not supported and should be rejected.  A decision from the PTAB on whether to institute IPR is expected by July 2015.   If IPR is instituted for any of the patents, the PTAB’s final written decision on the validity of the patents would follow in a year.  The decision is likely to precede the filing of Boehringer’s biosimilar application with FDA since its Phase III clinical trials are still ongoing.

While it is clear that biosimilar makers view IPRs as appealing for obtaining patent certainty long prior to litigation in district court, the extent to which IPRs will be used as an alternative to litigation under the BPCIA depends on what success biosimilar makers will have before the PTAB and a case by case analysis of the available defenses and prior art.  Defenses such as lack of enablement and written description often feature in patent litigation involving biologics but are not available in IPRs.  In addition, although IPRs do not require a case or controversy and, to date, the PTAB has invalidated patents in all industries at a very high rate, biosimilar makers risk gold-plating the challenged patent if the PTAB ultimately upholds its validity and the best defenses were those advanced in the IPR.  In those circumstances, a biosimilar maker may be left to litigate only the infringement of a valid patent under the BPCIA.