In the recent decision of University of California v. Eli Lilly and Co., 43 USPQ2d 1398 (Fed. Cir. 1997), the court held that a patent specification which includes by example a process for obtaining human insulin-encoding cDNA, and which describes the protein (amino acid sequence) that the cDNA encodes, but which does not describe the structure of the claimed cDNA in terms of its nucleotide sequence, does not comply with the written description requirement of 35 U.S.C. §112, first paragraph.¹ The court also held that the cDNA nucleotide sequence for rat insulin, as described by the patentee, did not provide a written description adequate to claim the genus of vertebrate or mammalian insulin cDNA.

In this lawsuit brought in 1990, the University of California (UC) alleged that Lilly infringed U.S. Patent No. 4,652,525 and one other patent. The subject patent relates to recombinant DNA technology and more particularly, to recombinant plasmids and microorganisms that produce human insulin.² Claim 1 of the '525 patent is directed to a recombinant plasmid containing within its nucleotide sequence cDNA or complementary DNA (more particularly, the reverse transcript of an mRNA) which encodes for vertebrate insulin. Claim 2 of the '525 patent is directed to a recombinant organism containing within its nucleotide sequence cDNA which encodes for vertebrate insulin. Claim 4 depending from claim 2 recites that the vertebrate is a mammal. Claim 5 depending from claim 2 recites that the vertebrate is a human.

The '525 patent describes a method of obtaining human insulin-encoding cDNA, the amino acid sequences of the A and B protein chains constituting human insulin, and the nucleotide sequence of rat insulin-encoding cDNA.

The Federal Circuit affirmed the district court's ruling that all of the claims of the '525 patent were invalid under 35 U.S.C. § 112, first paragraph, as failing to provide an adequate written description of the claimed cDNA.

Relative to claim 5, although the '525 patent does describe a method of obtaining the claimed cDNA, the court found that the '525 patent failed to describe the structure (i.e., nucleotide sequence) of the claimed human insulin-encoding cDNA. Citing Fiers v. Sugano, 25 USPQ2d 1601 (Fed. Cir. 1993), the court held that:

Moreover, the court also held that the description in the '525 patent of the amino acid sequences of the A and B chains constituting human insulin does not provide a written description of cDNA encoding for human insulin. This is because the structure of the protein itself is insufficient to positively determine the nucleotide structure of the corresponding natural DNA due to degeneracy of the genetic code.³

By analogy, the court also reasoned that because a prior art disclosure of the amino acid sequence of a protein would not necessarily render DNA encoding the protein obvious (also due to degeneracy of the genetic code), the same disclosure would not be sufficient to describe that invention for purposes of 35 U.S.C. §112, first paragraph.

Relative to claims 1, 2 and 4, the court adopted Lilly's view that the description of rat insulin cDNA (species) was not a description of the broad classes of vertebrate or mammalian insulin cDNA as claimed (genus). Namely, according to the court:

Restated, the '525 patent does not instruct which nucleotide sequences, other than that of rat insulin cDNA, are within the scope of the claimed vertebrate or mammalian insulin cDNA. Claiming all DNA's that achieve a result (e.g., all DNA's which encode for vertebrate insulin) without defining what means will do so (the structural features common to all vertebrate insulin DNA which distinguish vertebrate insulin DNA from others) does not comply with the description requirement.

The court acknowledged that a description of a genus of cDNA's may be achieved by means of a recitation of a representative number of cDNA's, defined by nucleotide sequence, falling within the scope of the genus, or by a recitation of structural features in common to the members of the genus. However, the naming of one member of such a group is not, in itself, a proper basis for a claim to the entire group. The court declined to speculate in what other ways a broad genus of genetic material may be properly described. However, the court was clearly of the view that the claimed genera of vertebrate and mammalian cDNA were not described by the nucleotide sequence of rat insulin alone.

This case is consistent with the Federal Circuit's previous holding in Fiers v. Sugano, namely, that an adequate description of DNA requires a description (structure or nucleotide sequence) of the DNA itself. The court's holding also provides that the isolation of a single DNA species (cDNA encoding for rat insulin) does not provide a written description adequate to claim the broad genus of vertebrate or mammalian insulin cDNA.

To fulfill the written description requirement, a patent specification must describe an invention and do so in sufficient detail that one skilled in the art can clearly conclude that as of the filing date the inventor had possession of the claimed invention. Thus, an applicant complies with the written description requirement by using such descriptive means as words, structures, figures, diagrams, formulas, etc., that set forth the claimed invention. Lockwood v. American Airlines, Inc., 41 USPQ2d 1961 (Fed. Cir. 1997). back

2) Generally, a recombinant DNA process is advantageously used to produce a protein in large quantity where the amount that can be recovered from natural sources is inadequate. In this technique, a foreign (e.g., human) gene which contains instructions for making a desired protein (e.g., a human hormone such as insulin) is isolated and inserted into the DNA (genetic material) of a bacterium or "host" cell by means of a carrier (vector). One type of vector is a "plasmid" which is a small circular piece of DNA present in some types of bacteria and which is capable of directing protein synthesis. Some of the genetically altered bacteria will produce the desired human protein, along with all of the other substances that the bacteria would ordinarily make. Those bacteria which produce the desired protein are grown and then "harvested" to recover the protein. back