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Court Finds Meaning to Claim Terms in Specification and Prosecution History

October 09, 2003

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Last Month at the Federal Circuit - November 2003

Judges: Rader (author), Schall, and Linn (dissenting-in-part)

In Genzyme Corp. v. Transkaryotic Therapies, Inc., No. 02-1312 (Fed. Cir. Oct. 9, 2003), the Federal Circuit affirmed a district court’s grant of SJ of noninfringement of U.S. Patent No. 5,356,804 (“the ‘804 patent”).

Genzyme Corporation (“Genzyme”) holds an exclusive license to the ‘804 patent, which is assigned on its face to Mount Sinai School of Medicine of New York University. The ‘804 patent claims a method of treating patients suffering from Fabry disease by producing human alphagalactosidase A (á-Gal A) and cells engineered to express and secrete active human á-Gal A. Genzyme filed suit against Transkaryotic Therapies, Inc. (“TKT”) based on a product involving a technique known as gene activation that activates an endogenous gene to express the endogenous human á-Gal A protein. It was undisputed that TKT’s technique does not integrate exogenous genes into the human host cells.

On appeal, Genzyme argued that the district court based its SJ decision on improperly construed claim terms “chromosomally integrated,” “regulatory sequence,” “stably,” and “compromising.” The Court interpreted the phrase “chromosomally integrated” standing alone to suggest “the incorporation of exogenous genetic code into the chromosomal material of the host cell.” The Court then interpreted the phrase in the context of the claims to explain that the exogenous sequence has a regulatory sequence that causes the host cell to stably overexpress á-Gal A. The cell then secretes the excess á-Gal A.

The majority found that ambiguity existed as to whether the exogenous sequence came from outside or within the host cell, and investigated the patent specification and the prosecution history to clarify the Applicant’s use of the term. The Court found that throughout the prosecution history, the Applicant had clearly envisioned the integration of an exogenous gene sequence into the host cell. In the specification, the Applicant consistently used the term “exogenous” to refer to the introduction of foreign genes into the host cell chromosome. Similarly, the Applicant distinguished his invention from the prior art through the insertion of an exogenous gene into a host cell. Accordingly, the Federal Circuit found that the district court did not err in its construing “chromosomally integrated” to require the introduction into a host cell of exogenous sequences encoding á-Gal A.

Because Genzyme had conceded noninfringement based on the district court’s construction of the term “chromosomally integrated,” the Federal Circuit affirmed the judgment of noninfringement.

Judge Linn dissented, concluding that the majority improperly construed “chromosomally integrated” by reading a limitation from the specification into the claim and improperly interpreting the prosecution history’s use of the term “integrated.”