PTAB Denies Institution of IPR for Amgen’s ENBREL Patent

On March 11, 2016, the Patent Trial and Appeal Board (PTAB) denied institution of Inter Partes Review (IPR) for U.S. Patent Number 8,163,522.  This is an important biotechnology patent, directed towards polynucleotides encoding a fusion protein comprising the extracellular region of an insoluble human TNF receptor and “all of the domains of the constant region of human IgG1 immunoglobulin heavy chain other than the first domain of said constant region.”  The ‘522 patent is owned by Hoffman-La Roche and exclusively licensed to Amgen - according to Amgen, the patent would be infringed by the marketing ofa biosimilar version of Amgen’s Enbrel.

The petition for IPR was brought by a group including Hayman Capital, Kyle Bass, and the Coalition for Affordable Medicine (hereinafter I will refer to the group as simply the “Coalition”).  The Coalition has made a name for itself filing IPR challenges on pharmaceutical patents and then essentially betting against the targeted companies (as discussed in a previous post).  In its petition challenging the ‘522 patent, the Coalition cited several prior art patents that disclose DNA sequences encoding the TNF receptor and immunoglobulin fusion proteins, and argued that it would have been obvious to combine the references to arrive at the claimed invention.

In denying institution of IPR, the Board found that the Coalition had “failed to show an articulated reason with a rational underpinning why one of skill in the art would have combined the teachings of [the cited prior art] to arrive at the claimed invention.”  All of the prior art cited by the Coalition was before the patent examiner during prosecution of the patent, and this appeared to weigh against its case.  Furthermore, the Board pointed out that the Coalition had not adequately addressed the objective indicia of nonobviousness presented to the Office during the prosecution of the patent.  This included “expert testimony concerning the unexpected results of improved TNF binding affinity, potency, kinetic stability, and reduced antibody effector function and aggregation ability.”

A decision to institute IPR would have been good news for Sandoz.  In a lawsuit filed February 26, 2016, Amgen charges Sandoz with infringing the ‘522 patent, based on FDA’s acceptance of Sandoz’s abbreviated Biologics License Application (“aBLA”) seeking approval to market a biosimilar version of Enbrel.  See Immunex Corp. v. Sandoz Inc., Case No. 2:16-cv-01888 (D.N.J.) (complaint).

In 2013, Sandoz had filed a declaratory judgment action seeking a determination that the ‘522 patent is invalid or would not be infringed by its biosimilar version of Enbrel.  In that case, however, the Federal Circuit upheld the district court’s decision to dismiss the case for lack of standing, given that at the time Sandoz had not filed an application for FDA approval to market a biosimilar version of Enbrel.  See Sandoz Inc. v. Amgen Inc., 773 F.3d 1274, 1275 (Fed. Cir. 2014).