Therasense, Inc. v. Becton, Dickinson and Co., 649 F.3d 1276

The district court voided Abbott's '551 patent for inequitable conduct due to nondisclosure of European Patent Office briefs.
Abbott prosecuted the '551 claims over the '382 patent, arguing a membraneless sensor for whole blood was disclosed; the district court found the prior art taught a membrane was optional but not required.
Abbott submitted declarations to the PTO (Sanghera) and attorney Pope arguing a skilled artisan would not read the '382 disclosure as requiring a membrane, contrary to their European representations.
Abbott had previously made inconsistent representations to the EPO asserting the membrane was optional, while to the PTO they argued it was not optional, creating nondisclosures.
The panel on appeal initially affirmed most aspects but a dissent led to en banc review to reform inequitable conduct standards.
The en banc court vacated the inequitable conduct judgment and remanded for new consideration under a but-for materiality (with an egregious misconduct exception) framework.

Issue	Plaintiff's Argument	Defendant's Argument	Held
What is the proper materiality standard?	Abbott argues higher Rule 56 standard applies.	BD/Therasense contends but-for materiality with egregious exception governs.	But-for materiality with egregious exception adopted; Rule 56-based approach rejected.
Must there be specific intent to deceive to prove inequitable conduct?	Abbott contends intent can be inferred from conduct with materiality.	Therasense argues explicit intent to deceive must be shown.	Specific intent required; not inferable from materiality alone.
Can the district court use Rule 56 as the materiality test or must it use but-for standard?	Rule 56-based materiality should govern.	But-for standard should govern unless egregious conduct applies.	Court adopts but-for standard with an egregious misconduct exception; remand on materiality.
Should the court remand to re-evaluate materiality and intent in light of the EPO disclosures?	Remand is unnecessary if materiality is clear.	Remand needed to reassess under the en banc standard.	Remand ordered for district court to re-evaluate under the new standard.
What is the proper remedy if inequitable conduct is found?	Entire patent unenforceable should be the remedy.	Remedial scope can be tailored to the violation.	Remedy is discretionary; not necessarily unenforceability of all claims on remand.

Keystone Driller Co. v. General Excavator Co., 290 U.S. 240 (Supreme Court 1933) (unclean hands; suppression of prior use justifies dismissal)
Hazel-Atlas Glass Co. v. Hartford-Empire Co., 322 U.S. 238 (Supreme Court 1944) (manufacture/suppression of evidence; deceitful patent procurement)
Precision Instrument Manufacturing Co. v. Automotive Maintenance Machinery Co., 324 U.S. 806 (Supreme Court 1945) (unclean hands; willful misconduct before PTO renders patent unenforceable)
Kingsdown Medical Consultants v. Hollister, Inc., 863 F.2d 867 (Fed. Cir. 1988) (intent to deceive requires sufficient culpability; not mere negligence)
J.P. Stevens & Co. v. Lex Tex Ltd., 747 F.2d 1553 (Fed. Cir. 1984) (Rule 56; starting point for materiality in inequitable conduct)
American Hoist & Derrick Co. v. Sowa & Sons, Inc., 725 F.2d 1350 (Fed. Cir. 1984) (sliding scale approach for intent/materiality critique)
Corona Cord Tire Co. v. Dovan Chemical Corp., 276 U.S. 358 (Supreme Court 1928) (but-for materiality considered; misrepresentation not always material)
Norton v. Curtiss, 433 F.2d 779 (Court of Customs and Patent Appeals 1970) (expanded view of 'fraud' under Rule 56; trust relationship with PTO)