Different Outcomes for IPR Challenges to the Same Patents Reveal Common-Sense Strategies for Improving Institution Rates

Two recent sets of decisions at the PTAB provide guidance on how to increase the likelihood of a petition being successful at instituting an IPR.

The first set of decisions relate to the erectile dysfunction (ED) drug tadalafil (CIALIS®).  In IPR2017-00323, Mylan successfully petitioned for an IPR against ICOS’s U.S. Patent No. 6,943,166, which claims, inter alia, administering “about 1 to about 20 mg, up to a maximum total dose of 20 mg per day.”  Mylan’s petition included expert testimony addressing what doses a person of ordinary skill would have expected to be suitable for tadalafil, based on the known dose of another ED drug, sildenafil (VIAGRA®), and the ratio of IC50 values for the two drugs.

MonoSol RX LLC filed a petition on the same patent, IPR2017-00412.  In support of its petition, MonoSol relied on an FDA document teaching one of ordinary skill that, in order to compete with sildenafil, a manufacturer would have to market tadalafil in a dose that had the same or better efficacy and that minimized side effects.  The PTAB was unpersuaded that this general guidance on dose selection was sufficient to create a reasonable likelihood that the claimed dose range was obvious, and so refused to institute an IPR.  In its denial of the petitioner’s request for a rehearing, the panel distinguished the Mylan petition, which included an estimated dose range based on known parameters, from the MonoSol petition, which included only on a general motivation to find a dose range.  The lesson is simple:  while dosing may often be a matter of routine development effort, IPR petitioners should locate prior art specific to the drug at issue to support the selection of a claimed dosage.

The second set of decisions relate to rituximab (RITUXAN®), which is used to treat certain autoimmune diseases and cancers.  Sandoz filed two petitions, IPR2017-02036 and IPR2017-02042, against Genentech’s U.S. Patent No. 7,976,838, which the PTAB rejected.  Pfizer filed its own petition, IPR2017-01923 and was successful in instituting an IPR.   In their decision rejection the Sandoz petitions, the PTAB cited to 35 U.S.C. 325(d), which gives the Board discretion to institute proceedings involving the same patent, based on arguments previously presented to the PTO, including during patent prosecution or in previous IPR petitions.  Central to the decisions was an IPR petition filed by Celltrion in August 2016, which had previously been rejected because Celltrion had not shown any claims were likely invalid.  According to the Board, Sandoz’s petitions were rejected because their arguments were “the same or substantially the same” as those in the failed Celltrion petition.  On the other hand, Pfizer’s petition was successful even though although it included some of the same references as Celltrion’s petition, because it also included new arguments supported by new evidence.  Whenever possible, IPR petitioners should include argument and art beyond that set forth in prior petitions.