Capon v. Eshhar
418 F.3d 1349, 2005 U.S. App. LEXIS 16865, 76 U.S.P.Q. 2d (BNA) 1078 (2005)
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Rule of Law:
The written description requirement of 35 U.S.C. § 112 does not impose a per se rule requiring a patent specification to recite the full nucleotide sequence of a claimed DNA molecule if the invention consists of a novel combination of DNA segments whose sequences are already well-known in the prior art.
Facts:
- Two groups of scientists, Capon et al. (Capon) and Eshhar et al. (Eshhar), independently developed inventions involving chimeric genes designed to enhance the human immune response.
- The invention involves creating an artificial gene by combining a DNA segment that encodes an antibody's specific antigen-binding domain with a DNA segment that encodes parts of a lymphocyte's signaling protein.
- This new chimeric gene, when expressed in an immune cell, creates a protein on the cell surface that combines the targeting ability of an antibody with the cell-killing function of a lymphocyte.
- The purpose of this technology is to direct immune cells to attack specific targets like tumor cells or virus-infected cells that they might not otherwise recognize.
- Both Capon's and Eshhar's patent filings described the general method for identifying, selecting, and linking these known DNA segments to create the chimeric gene.
- The filings provided specific examples and cited existing scientific literature for the component DNA sequences and linking procedures, but did not list the complete nucleotide-by-nucleotide sequence for every possible chimeric gene covered by the claims.
Procedural Posture:
- Capon obtained U.S. Patent No. 6,407,221 and Eshhar filed U.S. Patent Application No. 08/084,994 for similar inventions.
- The U.S. Patent and Trademark Office (PTO) instituted a patent interference proceeding to determine which party was the first inventor of the common subject matter.
- During the proceeding, an administrative patent judge at the Board of Patent Appeals and Interferences (the Board) sua sponte raised the issue of whether either party's specification met the written description requirement of 35 U.S.C. § 112.
- After an inter partes proceeding on this issue, the Board held that neither Capon's nor Eshhar's specification provided an adequate written description to support their claims.
- The Board invalidated all contested claims for both parties and dissolved the interference without deciding priority of invention.
- Both Capon (as appellant) and Eshhar (as cross-appellant) appealed the Board's decision to the U.S. Court of Appeals for the Federal Circuit.
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Issue:
Does the written description requirement of 35 U.S.C. § 112 mandate that a patent specification recite the complete nucleotide sequence of a claimed chimeric DNA molecule when the sequences of its constituent DNA segments are already known in the prior art?
Opinions:
Majority - Judge Pauline Newman
No. The written description requirement does not impose a per se rule that a patent specification must recite the full nucleotide sequence of a claimed DNA molecule when its component parts are known in the prior art. The descriptive requirement for a patent specification varies with the nature of the invention and the state of existing scientific knowledge. The Board of Patent Appeals and Interferences erred by creating an inappropriate generalization that required the inventors to re-describe information already well-known to those skilled in the art. The purpose of the written description is to demonstrate that the inventor was in possession of the invention, not to require the re-statement of established scientific data. Precedent, such as Regents v. Lilly, which required sequence data, is distinguishable because those cases involved the discovery of previously unknown DNA sequences, whereas the invention here is the novel combination of known sequences. Because the component DNA sequences were known, a person of ordinary skill in the art would understand the structure of the resulting chimeric gene without it being explicitly recited. The court vacated the Board's decision and remanded for a claim-by-claim analysis of whether the specification's examples and general teachings adequately support the full scope of the claims.
Analysis:
This decision significantly clarified the application of the written description requirement in biotechnology, particularly for inventions built from known genetic components. It pushed back against an overly rigid interpretation of precedent that would have required inventors to physically create and sequence every permutation of a claimed genus. The ruling provides greater protection for 'platform' or 'modular' inventions where the inventive concept lies in a new combination or method, rather than the discovery of a new biological molecule. The case reinforces the principle that the written description standard is flexible and must evolve with the state of scientific knowledge and predictability in a given field.
