Addressing the issue of prosecution history disclaimer, the US Court of Appeals for the Federal Circuit upheld the district court’s claim construction, finding that selected statements during prosecution did not constitute a “clear and unambiguous” surrender of claim scope when considered in the context of the prosecution history as a whole. Mass. Inst. of Tech. v. Shire Pharm., Inc., Case No. 15-1881 (Fed. Cir., Oct. 13, 2016) (Stoll, J) (O’Malley, J, concurring). 

The claims at issue were drawn to synthetic, biodegradable scaffolds upon which cells can grow in vitro to generate artificial tissues that can be administered to a patient. Scaffolds for cell growth had been used in the prior art to grow thin layers of artificial skin but were limited because blood vessels could not penetrate the artificial tissue, and as a result cells in the middle of a thicker tissue would die from lack of oxygen. The improved scaffolds developed by MIT scientists addressed this problem by supporting blood vessel growth, thereby allowing for the growth of thicker tissue implants, such as intestine, kidney, liver, blood vessel, nerve and muscle tissues, as well as thicker skin tissues. 

The claims specified that the “cells derived from a vascularized tissue” attach to the claimed “three-dimensional scaffold” to generate “vascularized organ tissue.” The district court construed these claim terms according to their plain and ordinary meaning, and Shire challenged these constructions. 

With respect to the “vascularized tissue” terms, Shire pointed to several statements made during prosecution in Examiner interviews, inventor declarations and office action responses as allegedly limiting the claim scope to non-skin tissues (a construction that would allow Shire’s artificial skin grafts to avoid infringement). 

The Federal Circuit upheld the district court’s rejection of Shire’s arguments, noting that a “clear and unambiguous disclaimer” of subject matter that would be “evident to one skilled in the art” is required to meet the “high standard” for prosecution history disclaimer. To assess whether such a disclaimer rises to the level of clear and unambiguous, “it is important to consider the statements made by the applicant both in the context of the entire prosecution history and the then-pending claims.” Although Shire had “plucked” several allegedly limiting statements from the prosecution history, which spanned more than 10 years, the Court noted that those statements were not made with respect to the claim terms at issue, but instead were made with respect to different claim language that did not even end up in the claims that finally issued. According to the Court, a skilled person reading the prosecution history as a whole would not understand those statements, taken out of context, to disclaim the ordinary meaning of the terms at issue.

With respect to the “three-dimensional scaffold” claim term, Shire argued that it was indefinite. The Court upheld the district court’s construction that was based on the accepted, ordinary meaning of the term as found in dictionaries. Shire objected to this evidence because the dictionaries were from the present day and not from the time of filing, but Shire failed to explain how contemporaneous dictionaries would have defined the term any differently. Moreover, the Court found it persuasive that Shire’s expert gave an opinion that was consistent with the plain meaning. For all of these reasons, the claim language was found to be definite under Nautilus.

Judge O’Malley concurred with the opinion and its reasoning, but wrote separately about a procedural issue. In particular, she reiterated her well-known position that patent cases are not final until the district court has determined damages and/or willfulness, and that the Federal Circuit should not have taken the present case. The Court’s Bosch decision (IP Update, Vol. 16, No. 6) continues to be good law, but at least one member of the bench is holding steady that Bosch was wrongly decided.