Immunex Corporation v. Sanofi-Aventis U.S. LLC, 977 F.3d 1212

Background

The ’487 patent claims isolated "human antibodies" that bind the human IL‑4 receptor; claim 1 recites an isolated human antibody that competes with a reference antibody (SEQ ID NO:10 and SEQ ID NO:12).
Scientific context: antibodies can be murine, chimeric, humanized (CDRs nonhuman, rest human), or fully human; humanized/chimeric embodiments are disclosed in the specification.
Sanofi petitioned two IPRs. In IPR2017‑01884 the PTAB (applying the BRI standard then in effect) construed "human antibody" to include partially human (including humanized) antibodies and found claims 1–17 obvious over Hart (murine antibody) combined with Schering‑Plough (humanizing grafting), invalidating the claims.
In IPR2017‑01879 the PTAB found certain claims not anticipated by Immunex’s earlier publication based on inventorship (disputing whether a technician, Boiani, was an inventor); Sanofi cross‑appealed that determination.
After briefing, Immunex filed a terminal disclaimer shortening patent term and sought a Phillips claim‑construction standard on appeal; the court declined and reviewed under BRI because the disclaimer was filed post‑decision and the record before the PTO controlled.
The Federal Circuit affirmed the PTAB’s BRI construction that "human antibody" includes partially human/humanized antibodies, affirmed the invalidity decision, and dismissed Sanofi’s inventorship cross‑appeal as unnecessary.

Issues

Issue	Immunex's Argument	Sanofi/Board's Argument	Held
Whether "human antibody" is limited to "fully human" or includes partially human/humanized antibodies	"Human antibody" means only fully human; humanized is not "human."	"Human antibody" reasonably includes partially human (humanized/chimeric) antibodies per the specification and prosecution history.	Court held under BRI that "human antibody" encompasses partially human/humanized antibodies.
Appropriate claim‑construction standard after a post‑decision terminal disclaimer	Apply Phillips (district‑court standard) because patent expired on appeal.	Review under the BRI standard because the terminal disclaimer was filed after the PTAB decision and the record before the PTO governs review.	Court applied BRI (did not pivot to Phillips).
Whether the PTAB erred in departing from a district court’s narrower Phillips‑based construction	The district court construed "human" as "fully human"; PTAB should have explained more for departing.	PTAB is not bound by prior district court construction under BRI and provided sufficient reasoning for appellate review.	Court found PTAB’s explanation adequate and did not err in reaching a broader construction.
Inventorship of mAb 6‑2 (Sanofi cross‑appeal) — whether Boiani was an inventor making the earlier publication §102(e) prior art	Boiani (another) was the inventor of mAb 6‑2, so the ’132 publication is prior art.	PTAB found Boiani was not an inventor.	Court dismissed cross‑appeal as unnecessary after affirming invalidity in the other IPR.

Key Cases Cited

Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (primary guide for claim construction and emphasis on intrinsic evidence)
Teva Pharms. USA, Inc. v. Sandoz, Inc., 574 U.S. 318 (2015) (defer to underlying factual findings in claim construction review)
Cuozzo Speed Techs., LLC v. Lee, 136 S. Ct. 2131 (2016) (standards for PTAB IPR procedures and review of PTAB decisions)
Power Integrations, Inc. v. Lee, 797 F.3d 1318 (Fed. Cir. 2015) (PTAB not strictly bound by prior district court constructions; must provide sufficient reasoning)
Nobel Biocare Servs. AG v. Instradent USA, Inc., 903 F.3d 1365 (Fed. Cir. 2018) (strong presumption against claim constructions that exclude disclosed embodiments)
In re Thorington, 418 F.2d 528 (C.C.P.A. 1969) (terminal disclaimers filed after PTO decision should not be considered in review)
Customedia Techs., LLC v. Dish Network Corp., 941 F.3d 1173 (Fed. Cir. 2019) (forfeiture of unraised Appointments Clause challenges)