932 F.3d 1342
Fed. Cir.2019Background
- Ajinomoto sued CJ at the International Trade Commission alleging importation of L-tryptophan made by processes that infringe U.S. Patent No. 7,666,655 (the ’655 patent), which claims E. coli engineered to overexpress the yddG membrane exporter (YddG) and methods using those bacteria.
- The ’655 patent describes enhancing yddG activity by (1) adding plasmid copies, (2) inserting additional chromosomal copies, or (3) using a stronger promoter in place of the native promoter; Claim 20 depends on claims (including 9 and 15) that embody these alternatives.
- CJ used three groups of strains: earlier strains with a single-nucleotide promoter mutation (stronger promoter by mutagenesis), first later strains with two yddG copies (one non-E. coli gene with additional promoters), and second later strains with a codon-randomized non-E. coli yddG plus strong promoters.
- The ALJ construed “replacing the native promoter ... with a more potent promoter” to require removal of the native upstream region and insertion of a promoter controlling a different gene, and found earlier strains noninfringing; the Commission adopted that construction and noninfringement for earlier strains but found both later strains infringing and claim 20 not invalid for lack of written description.
- On appeal, Ajinomoto challenged the promoter-construction (arguing single-nucleotide mutagenesis should qualify); CJ cross-appealed issues including equivalence for the second later strain, the resistance limitation, and written-description invalidity. The Federal Circuit affirmed the Commission in all respects.
Issues
| Issue | Plaintiff's Argument (Ajinomoto) | Defendant's Argument (CJ) | Held |
|---|---|---|---|
| Construction of "replacing the native promoter ... with a more potent promoter" | Should cover promoter-strengthening by single-nucleotide mutagenesis of the native promoter | Language, specification, prosecution history show "replace/substitute" means remove native promoter and insert a different promoter | Court: Affirmed Commission — "replace" means substituting the promoter as a unit (not single-nucleotide mutagenesis) |
| Infringement by earlier strains | Earlier strains’ promoter-strengthening via single-nucleotide mutation meets the replacement limitation | Earlier strains do not remove/insert promoters and thus do not meet the claim limitation | Court: Earlier strains do not infringe under the correct construction |
| Doctrine of equivalents for second later strain (protein limitation) | The codon-randomized non‑E. coli YddG protein is equivalent to claimed SEQ ID NO:2 (function-way-result) and prosecution history estoppel is rebutted (tangential relation) | Amendment during prosecution (narrowing claim language) estops Ajinomoto from asserting equivalents; the accused protein is not equivalent | Court: Substantial evidence supports equivalence; prosecution‑history estoppel rebutted under the tangential‑relation exception; infringement under equivalents affirmed |
| Written‑description challenge to “more potent promoter” genus | Genus of “more potent promoters” lacks adequate written description—claim should be invalid | Specification and cited art disclose representative promoters and structural features (consensus sequence correlation) enabling skilled artisans to identify more potent promoters | Court: Commission reasonably found adequate written description; claim 20 not invalid |
Key Cases Cited
- Teva Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831 (2015) (claim construction review where subsidiary factual findings receive deference)
- Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722 (2002) (presumption of prosecution history estoppel after narrowing amendment and rebuttal paths)
- Kinik Co. v. Int’l Trade Comm’n, 362 F.3d 1359 (Fed. Cir. 2004) (standard: infringement fact findings reviewed for substantial evidence)
- Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336 (Fed. Cir. 2010) (written‑description standard for genus claims: representative species or common structural features)
- Norian Corp. v. Stryker Corp., 432 F.3d 1356 (Fed. Cir. 2005) (patentee may surrender more during prosecution than minimally required)
- Springs Window Fashions LP v. Novo Indus., L.P., 323 F.3d 989 (Fed. Cir. 2003) (applicants are held to representations made during prosecution)