There are many things that the U.S. Patent and Trademark Office (USPTO), or a district court judge in litigation, considers during the slippery process of claim construction. Among the less-sharply defined criteria is whether an applicant or patentee disparaged or disavowed a particular approach to practicing the invention. If the applicant, in the specification or during prosecution, expressly disavows a particular approach, then it’s fair for the public to assume that the inventor did not intend to cover that approach in his or her claims. But rarely are express disavowals made, where the applicant unambiguously states, “I hereby don’t want to cover this concept in my claims!”

Disparagement, however, is often difficult to assess, because it is always a question of degree. An unrestrained attack on a particular technical approach as utterly unworthy is a clear case where disparagement rises to the level of disavowal. However, a mere mention that an improvement would be desirable in an approach may not result in a disavowal. Understanding how far we can go down this road before claim scope is affected is important for drafters of patent specifications and claims.

A recent case decided on September 28, 2012, at the Court of Appeals for the Federal Circuit adds to the U.S. law of claim construction when disparagement and disavowal are at issue. In the case of In re Abbott Diabetes Care, Inc., Nos. 2011-1516, -1157 (Fed. Cir. Sept. 28, 2012), the court was asked by Abbott to review an adverse decision at the USPTO’s Board of Patent Appeals and Interferences (Board) in two ex parte reexamination proceedings. During the reexams, the Board rejected numerous claims of U.S. Patent Nos. 6,175,752 (“the ’752 patent”) and 6,565,509 (“the ’509 patent”).

The ’752 patent and the ’509 patent share a common specification that discloses methods and devices for in vivo monitoring of an analyte, specifically, blood glucose in diabetics, using an implanted electrochemical sensor. The specification stated that the disclosed sensor overcame limitations in the prior art related to the bulk and size of prior art sensors, as well as the prior art’s reliance on external wires and cables connecting the various components that interfered with the daily life of the patient. Specifically, the specification noted that existing sensor guides “are typically bulky and do not allow for freedom of movement.”

The proper construction of “an electrochemical sensor,” as claimed in both the ’752 and ’509 patents, was a central issue of this case. The examiner held that the broadest reasonable interpretation of “electrochemical sensor” included wires and cables, even though the specification criticized the external cables and wires of the prior art, and none of the embodiments in Abbott’s patents included external cables or wires connecting to the associated control unit.

The Board upheld the examiner during the USPTO appeal and held that, in the absence of a more express limiting statement, the broadest reasonable interpretation in light of the specification of the term “electrochemical sensor” includes wires and cables.

Having construed the term to include wires, the rejection of the claims using prior art sensors having wires was, not surprisingly, upheld. The real question remained: was the claim construction reasonable?

Abbott filed requests for rehearing, arguing to no avail that the Board improperly relied on the specification’s statement that “sensors include cables or wires.” Abbott argued that the statement was made to criticize the prior art sensors and not to describe the claimed “electrochemical sensor.” The Board brushed Abbott’s argument aside, holding that the statement instead “provides insight as to how one of ordinary skill in the art would interpret the term ‘sensor.’” The Board maintained its reasoning that because nothing in Abbott’s patents explicitly disclaims sensors that include external cables or wires, the broadest reasonable interpretation of the claims should still include these features.

On appeal to the Federal Circuit, Abbott reiterated that the broadest reasonable interpretation of the claims should not include cables or wires. Abbott pointed out that none of its disclosed embodiments included wires or cables, and in fact many embodiments including “contact pads” for electrical connectivity wouldn’t function for their intended purposes if wires were included. During the Federal Circuit appeal, the USPTO argued that Abbott’s specification acknowledged, albeit in a disparaging manner, that the prior art included external cables or wires.

The interpretation of Retractable Technologies, Inc. v. Becton, Dickinson & Co., 653 F.3d 1296, 1306 (Fed. Cir. 2011), played a significant role in this case. The USPTO argued that Retractable Technologies stands for the proposition that statements about “the difficulties and failures in the prior art, without more, do not act to disclaim claim scope.” Id. The USPTO further argued that absent a specific disavowal, disparagement would not operate to limit the claims’ broadest reasonable interpretation. The Federal Circuit disagreed. In Retractable Technologies, the patentee’s supposed disclaimer of “cutting” in the background of the invention was undermined by an embodiment in the specification that indicated that some forms of cutting fell within the scope of the invention. Unlike the patents in Retractable Technologies, every embodiment disclosed in Abbott’s specifications showed an electrochemical sensor without external cables or wires. The only mention of a sensor with external cables or wires in Abbott’s patents is a single statement addressing the primary deficiency of the prior art. Further, the court emphasized that the specifications of Abbott’s patents “repeatedly, consistently, and exclusively” described sensors without wires, while simultaneously disparaging sensors with external cables or wires. Overall, based upon the findings discussed above, the Federal Circuit found the USPTO’s interpretation of “an electrochemical sensor” unreasonable.

In the wake of the In re Abbott decision, applicants facing stubborn rejections based on unreasonable claim constructions at the USPTO should be encouraged by this decision. Where the specification and claims are directed to something clearly different than what’s shown in the prior art, applicants have sometimes struggled to overcome opportunistic rejections where their specifications do not contain the “magical language” of an explicit disavowal. Applicants can always argue that the claims as a whole, based on the specification (which is the single best guide to the meaning of the claims), are the basis for the broadest reasonable interpretation of the claims, but as this case’s history demonstrates, positions can become entrenched. Looking forward to a new era when America Invents Act post-grant challenges become more commonplace, and the body of Federal Circuit case law is based on appeals from these procedures (which will apply the broadest reasonable interpretation standard), patent applicants and the USPTO alike will gain more frequent guidance from the Federal Circuit.