IP News

On April 26, 2010, the Federal Circuit granted plaintiffs-appellants Abbott Diabetes Care, Inc. et al.'s petition for rehearing en banc, vacated the panel opinion in Therasense, Inc. v. Becton, Dickinson & Co., 593 F.3d 1325 (Fed. Cir. 2010) holding U.S. Patent No. 5,820,551 (“the '551 patent”) unenforceable due to inequitable conduct, and requested the parties file new briefs addressing the following issues:

1. Should the materiality-intent-balancing framework for inequitable conduct be modified or replaced?
2. If so, how? In particular, should the standard be tied directly to fraud or unclean hands? If so, what is the appropriate standard for fraud or unclean hands?
3. What is the proper standard for materiality? What role should the United States Patent and Trademark Office's rules play in defining materiality? Should a finding of materiality require that but for the alleged misconduct, one or more claims would not have issued?
4. Under what circumstances is it proper to infer intent from materiality?
5. Should the balancing inquiry (balancing materiality and intent) be abandoned?
6. Whether the standards for materiality and intent in other federal agency contexts or at common law shed light on the appropriate standards to be applied in the patent context.

The '551 patent relates generally to the field of disposable blood glucose test strips used by diabetic patients to test insulin levels. When whole blood is introduced to a test strip, the glucose in the blood reacts with an enzyme on the strip, transferring electrons to an “active electrode” sensor on the strip. Prior art sensors employed membranes over the electrode for a variety of reasons, including, e.g., as a safety measure to prevent the chemistry from dissolving into the body. The '551 patent claims a test strip with an electromechanical sensor for testing whole blood without any membrane over the electrode.

The original application leading to the '551 patent, and subsequent continuation applications, were repeatedly rejected for anticipation and obviousness over, inter alia, U.S. Patent No. 4,545,382 (“the '382 patent”), which issued from an application filed by one of Abbott's predecessors. The '382 patent discloses electrochemical sensors in which a protective membrane is optional in all cases except the case of live blood, in which case the protective membrane is “preferred ' but not required.” Abbott argued during prosecution (via declaration and affidavit) that one of ordinary skill would have understood the “preferred” language in the '382 patent as “patent phraseology” and that a membrane is required for active electrodes designed for use with any whole blood test. Based on this representation, the PTO allowed the '551 patent to issue with the membraneless sensor claims.