Federal Circuit Reins In Doctrine of Inequitable Conduct in Therasense, Inc. v. Becton, Dickinson & Co.
On May 25, 2011, the Court of Appeals for the Federal Circuit handed down an en banc decision in Therasense, Inc. v. Becton, Dickinson & Co., revamping the standards used for judging patentees’ inequitable conduct in patent infringement cases. Significantly, the decision raises the bar for accused infringers wishing to demonstrate the requisite intent and materiality needed to support a finding of inequitable conduct. In particular, the decision reaffirms that intent and materiality standards are to be independently applied, and establishes a “but-for” test for materiality that is satisfied only when a patent claim would not have been allowed in prosecution but-for an alleged bad act (for example, a failure to disclose certain prior art references). It is hoped that the heightened standards will reduce the incidence of unwarranted inequitable conduct claims made by accused infringers during patent litigation, and reduce the volume of marginally relevant prior art disclosures made by patentees during patent prosecution.
Therasense sued Becton, Dickinson (“BD”) in the United States District Court for the Northern District of California, inter alia, for infringing U.S. Patent No. 5,820,551. Abbott filed the original application leading to the ’551 patent in 1984. The ’551 patent involves disposable blood glucose test strips for diabetes management. When blood contacts a test strip, glucose in the blood reacts with an enzyme on the strip, resulting in the transfer of electrons from the glucose to the enzyme. A mediator transfers these electrons to an electrode on the strip. Then, the electrons flow from the strip to a glucose meter, which calculates the glucose concentration based on the electrical current.
During prosecution, the original application saw multiple rejections for anticipation and obviousness, including repeated rejections over U.S. Patent No. 4,545,382, another patent owned by Therasense. In 1997, Therasense amended the claims to claim a new sensor that did not require a protective membrane for whole blood. Therasense asserted that this distinguished over the sensors disclosed by the ’382 patent, whose electrodes allegedly required a protective membrane. In response to a request by the examiner, Therasense submitted a declaration to this effect in the U.S. Patent and Trademark Office (“PTO”). Several years earlier, while prosecuting the European counterpart to the ’382 patent, Therasense made representations to the European Patent Office (“EPO”) arguing that such a membrane could be used in their invention but was not required. This representation was not disclosed to the examiner examining the original application leading to the ‘551 Patent.
