PTAB Issues Final Written Decision Finding Immunex’s Patent at Issue in Dupixent® Litigation Unpatentable

Yesterday, the PTAB issued final written decisions in two IPR proceedings (IPR2017-01884 and IPR2017-01879) it instituted on February 15, 2018 against U.S. Patent No. 8,679,487 (the ’487 patent), held by Immunex.  The ’487 patent is directed to isolated human antibodies that compete with a reference antibody for binding to human interleukin-4 (IL-4) receptor.  This patent is also at issue in district court litigation regarding Sanofi-Aventis and Regeneron’s Dupixent® (dupilumab) biologic, a monoclonal antibody used to treat eczema, among other conditions.  The PTAB found the ’487 patent invalid under IPR 2017-01884, but not under IPR 2017-01879.

As explained by the PTAB in IPR 2017-01884, the ’487 patent is directed to “compositions and methods for treating certain conditions induced by interleukin-4 (IL-4) by administering an IL-4 antagonist.”  IPR 2017-01884, Paper 96 at 2.  Specifically, the patent requires creating an “isolated human antibody that competes with a reference antibody for binding to human IL-4 interleukin-4 (IL-4) receptor.”  Id. at 4.  Petitioners Sanofi and Regeneron challenged the validity of the ’487 patent in IPR 2017-01884 based on two prior art references.  The PTAB found that one prior art reference disclosed a murine antibody with the claimed characteristics that “inherently ‘competes’” with mAb 12B5, a “IL-4R human monoclonal antibodies (MAbs) produced by immunizing transgenic mice.”  Id. at 11.  Thus, the first prior art reference taught “every limitation of claim 1 except that it is a murine instead of a human antibody.”  Id. at 16.  A second prior art reference provided the “missing limitation through its description of techniques for humanizing murine anti-hIL-4R blocking antibodies so they can be employed for long term treatment of allergic disorders.”  Id.  These references rendered the claims unpatentable as obvious.  The PTAB rejected the Patent Owner’s arguments that the Petitioner improperly ignored other strategies that a POSA could have pursued, stating that “although others in the art (including Petitioner) may have been pursuing different avenues for inhibiting IL-4 activity, that activity is inapposite to our analysis. Patent Owner has not identified any persuasive evidence in the record that teaches away from humanizing MAb230.”

The PTAB also issued a final written decision in IPR 2017-01879 that the ’487 is not unpatentable as anticipated by US 2002/0002132 (“the ’132 publication”), published Jan. 3, 2002.  Petitioner alleged that the ’132 publication is § 102(e) prior art to the ’487 patent.  The PTAB held that while the inventive identities of the ’132 publication and the ’487 patent are different, the portions of the ’132 publication relied upon by the Petitioner were, in fact, the work of the inventors of the ’487 patent.  The PTAB relied on “declarations from the ’487 patent inventors, declarations from two corroborating witnesses who worked with the inventors, and various contemporaneous meeting minutes” submitted by the Patent Owner in making this finding.  Thus, because the PTAB found that the Petitioner had not satisfied its burden in proving that the ’132 publication is § 102(e) prior art, the PTAB determined that the ’132 publication did not anticipate the ’487 patent.

The ‘487 patent is also the subject of ongoing litigation in the Central District of California (Immunex Corporation v. Sanofi (Civil Action No. 2:17-cv-02613)), where Immunex has alleged that Sanofi and Regeneron’s Dupixent® (dupilumab) biologic infringes the ‘487 patent.  The most recent coverage of that suit can be found here.  Stay tuned for updates on how the case progresses in light of these decisions.