In Invitrogen Corp. v. Biocrest Mfg. (Fed. Cir. May 7, 2003), the Federal Circuit ruled a patent disclosed an invention’s context for claim coverage notwithstanding preparatory steps of an accused infringer.

The subject patent is directed to DNA technology.  DNA molecules have nucleotide sequences called genes that act as blueprints for the production of proteins usable in medical treatment.  A transformable E. coli cell is one that accepts foreign DNA.  The capacity of the cell to accept the foreign DNA is called competence.  The E. coli serves as a factory to replicate by cell division many copies of the DNA molecule and its particular gene to be expressed as the proteins.  The patent owner accused another party of infringing claims of the patent, including claim 1 as follows:

1.         A process for producing transformable E. coli cells of improved competence by a process comprising the following steps in order:

(a)        growing E. coli cells in a growth-conducive medium at a temperature of 18 ºC. to 32 ºC.;

(b)        rendering said E. coli cells competent; and

(c)        freezing the cells.

The accused infringer makes competent E. coli cell lines by a process that includes the steps of incubating cells at 37 ºC, growing the cells in a fermenter at 26 ºC, and freezing the cells.  A point of dispute was whether the accused infringer’s “incubating” step at 37 ºC, outside the patent owner’s step (a) temperature range of 18 ºC to 32 ºC, removed the accused infringer from infringement of claim 1.

On appeal, the Federal Circuit set forth a construction of claim 1.  First, the court reviewed the language of the claim.

Claim 1 recites that the specific cells formed at 18 ºC to 32 ºC in step (a) are rendered competent in step (b).

• The language of steps (a) and (b) does not address or limit, and therefore permits, earlier growth at temperatures outside the range of 18 ºC to 32 ºC.
• The open-ended transition “comprising” signals to patent practitioners that claim 1 allows activity, even activity that produces E. coli cell growth, before steps (a) and (b) and without limitation to the 18 ºC to 32 ºC temperature range.

Second, the court reviewed the specification of the patent and found disclosure of growth and storage steps at temperatures outside the range 18 ºC to 32 ºC as preparatory to execution of the process of claim 1.  The disclosure in the specification supplied context about the understanding of skilled artisans as well as the field of invention and confirmed for the court that claim 1 does not disavow growth before step (a).

Third, the court reviewed the prosecution history of the patent in context and held the inventors had not disclaimed all growth above 32 ºC but instead emphasized the advantages of growth at 18 ºC to 32 ºC immediately before rendering the E. coli competent.

Recommendation:

To ensure prospective enforceability of a patent, an important component in the careful preparation of the patent application is a disclosure in the specification of context for the claimed invention about the field of invention and the understanding of skilled artisans.

May 9, 2003

Text Copyright © 2003 Bob Brill et al.

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