## Facts

- The Regents of the University of California (UC) owned two patents directed to recombinant DNA technology for producing human insulin: U.S. Patent Nos. 4,652,525 and 4,431,740.
- The asserted ’525 patent claims covered, among other subject matter, recombinant plasmids and microorganisms containing cDNA encoding human insulin and capable of producing human insulin.
- The ’525 patent specification described work focused on rat insulin cDNA, provided amino acid sequences for human insulin A and B chains, and described general methods for obtaining human insulin cDNA, but did not disclose the nucleotide sequence (or comparable structural description) of human insulin cDNA.
- Eli Lilly manufactured human insulin using a process involving semi-synthetic DNA constructs that encoded fusion proteins.
- UC sued Lilly for infringement (including under the doctrine of equivalents). The district court found no infringement, held the asserted ’525 claims invalid for lack of adequate written description, and held both patents unenforceable for inequitable conduct.
- UC appealed, challenging venue/jurisdiction, invalidity, noninfringement, and the inequitable-conduct ruling.

## Issues

1. Whether the trial court properly retained and exercised jurisdiction for trial after transfer.
2. Whether the asserted claims of the ’525 patent were invalid for failure to satisfy the written description requirement of 35 U.S.C. § 112.
3. Whether Lilly infringed the asserted claims of the ’740 patent, literally or under the doctrine of equivalents.
4. Whether the patents were unenforceable for inequitable conduct.

## Decision

- The Federal Circuit affirmed the district court’s exercise of jurisdiction for trial.
- The Federal Circuit affirmed invalidity of the asserted ’525 claims for lack of adequate written description.
- The Federal Circuit affirmed the finding of no infringement of the ’740 patent.
- The Federal Circuit reversed the inequitable-conduct determination and the resulting unenforceability ruling.
- Disposition: affirmed in part and reversed in part.

## Legal Principles

- For DNA-related claims, written description requires disclosure of the claimed DNA itself; a statement that the DNA is part of the invention plus a general isolation method is insufficient.
- Adequate written description for a claimed DNA commonly requires structural information (such as sequence information) identifying which nucleotides constitute the claimed molecule, especially when claiming human or other broad genus members.
- Disclosure of one species (e.g., rat insulin cDNA) and generalized methods does not necessarily describe broader classes (e.g., human or mammalian insulin cDNA) absent structural identifying information commensurate with the claim scope.
- Prosecution history can narrow claim scope and preclude coverage of subject matter surrendered to overcome prior art, limiting both literal infringement and infringement by equivalents.
- Inequitable conduct requires proof of materiality and intent; unenforceability is not supported where alleged misstatements are not material and withheld references are cumulative of information already before the examiner.

## Conclusion

The Federal Circuit held that broad claims to human insulin-encoding cDNA failed written description where the specification lacked a structural description of the human cDNA, affirmed noninfringement based on narrowed claim scope excluding fusion-protein constructs, and reinstated enforceability by rejecting inequitable conduct absent sufficient materiality and intent.


Regents of the Univ. of Cal. v. Eli Lilly & Co., 119 F.3d 1559 (Fed. Cir. 1997)