Federal Circuit Heightens Written Description Requirement for Patents on Genetic Material

On April 2, 2002, the Federal Circuit issued an opinion in Enzo Biochem, Inc. v. Gen-Probe Inc., No. 01-1230 (Fed. Cir. Apr. 2, 2002), that is important to all holders of and applicants for patents covering genetic materials. The Federal Circuit, the court responsible for maintaining uniformity of the laws governing patents, affirmed and expanded upon an increasingly strict standard for the written description requirement for such patents. Based on this opinion, a patent that does not describe the nucleotide sequence of the claimed genetic material may be held invalid, even where (1) someone ordinarily skilled in the art would fully understand the claimed invention, and (2) the description is supported by a deposit of the nucleic acid molecule in issue.

The Written Description Requirement. To receive a United States patent, an inventor must provide a specification that contains "a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains or with which it is most nearly connected, to make and use the same." 35 U.S.C. § 112, ¶ 1. Courts had held that the analysis of this requirement involves fact-specific, case-by-case consideration of the invention in light of the relevant art.

In Regents of the University of California v. Eli Lilly & Co., 119 F.3d 1559 (Fed. Cir. 1997), the Federal Circuit suggested that this requirement might apply more stringently in cases involving genetic material. In that case, the patent described the nucleotide sequence of cDNA encoding rat insulin and a method of obtaining cDNA encoding for other vertebrate insulins, including human insulin, but failed to describe the nucleotide sequence of cDNA encoding human or other vertebrate insulin. The claims of the patent pertaining to human and other vertebrate insulins were found invalid on the basis that they did not satisfy the written description requirement.

The decision was subject to extensive criticism, much of it centering around the fact that, for those skilled in the art, the disclosure of the patent made it routine to derive the human and other vertebrate cDNA. The disclosure of the patent appeared to be comparable in specificity and detail to written descriptions found to be adequate in other technologies. Many hoped that the case would be limited to its facts, and did not represent a sign that biotech inventions would be subject to more rigorous description requirements than other arts.

The Enzo Decision. The Enzo case indicates that, in fact, a higher standard will apply. In Enzo, the Federal Circuit considered the written description of a patent covering nucleic acid probes that selectively hybridize to genetic material of bacteria that cause gonorrhea. A significant difference in this case was that the specific nucleic acid molecules used as hybridization probes, critical for selecting between the different types of gonorrhea, had been deposited with the American Type Culture Collection, in accordance with In re Lundak, 773 F.2d 1216 (Fed. Cir. 1985),and the Manual of Patent Examining Procedure (MPEP). Further, the patent had been issued with no written description rejection. Nevertheless, the court determined that, because the inventor had not described the actual nucleotide sequence of the probes in the patent specification, the written description was inadequate as a matter of law.

In so holding, the Federal Circuit characterized the description of the probes as functional, rather than structural, and held that a structural definition was necessary to meet the written description requirement. Notably, the court also made two other observations. First, it held that consideration of the knowledge of those skilled in the art was irrelevant. In other words, because the description did not describe the structure itself, the court did not need to inquire into whether the patent provided enough information for those skilled in the art to glean the requisite information.

Second, the court also concluded that the inventor was not protected by having placed samples of the probes on deposit with the American Type Culture Collection. Despite reliance by the inventor on regulations covering this area, the court nevertheless concluded that adequacy of the written description rested solely on what was disclosed in the patent itself.

What Does This Mean To You? The Enzo decision may have serious implications for your patent prosecution strategy, particularly dealing with patents describing genetic material. You may need to provide more extensive background material, even if it is commonly known to those who are skilled in the art, because it may be more difficult to supplement that information later. Wherever possible, you will want to describe inventions of genetic material by nucleotide sequence, keeping in mind that even placing a sample of the material on deposit may not be enough to ensure the validity of your patent. You are likely to want to seek patents not only on the materials you invent, but also on the methods by which you develop them. If you have developed a new method, you may want to wait before seeking patent protection to make sure that you have an opportunity to derive and describe new materials obtainable by your process. You will want to weigh the benefits of waiting, however, against the potential risk of having a later inventor file before you, creating a dispute over priority.

If you are involved in litigation involving patents on genetic material, there may be an increased likelihood that the patents will be subject to invalidation on the grounds of an inadequate written description. Therefore, patent holders should be especially cautious about litigating, rather than licensing, such patents. Accused infringers should study carefully whether patents asserted against them might be invalid on the basis of an inadequate written description.

From a more scientific perspective, descriptions relating to the broadly claimed compound may be complemented by the disclosed sequence of the target nucleic acid. Therefore, describing the target sequence may provide for an initial understanding of what is required to bind to the target (i.e. the spatial relationship between the target and the compound, the hydrogen bonding patterns, the local environment, and the geometric constraints). One of ordinary skill in the art will readily recognize that the known sequence of a target nucleic acid will dictate the structure of the claimed compound binding to the target sequence based upon the "forces" presented by the target. The "genetic material of a bacteria" as a target, in view of Enzo, probably will not be enough.

Giving a detailed understanding of the target in a parent application provides a "crutch" for the inventor to disclose and claim compounds discovered over time, and be filed in subsequent applications. Since there are many non-nucleic acid compounds that inhibit target nucleic acid function and cannot be described by a known "sequence," the inventor should describe the target as clearly as possible. One of skill will recognize the characteristics of a target nucleic acid that are relevant identifying characteristics of the claimed compound.

Also, from the investor’s - - and derivatively - - the emerging biotechnology company’s perspective - - the Enzo decision introduces further uncertainty into an approval process that already requires significant risk capital and patience. Early- round investors may no longer be willing to assume as much risk, and may insist on sharing that risk with co-investors. As a result, the cost to biotech companies of attracting investment capital may become significantly higher, as investors insist on lower valuations to offset the Enzo decision. In addition, biotech companies may have to "go to market" more frequently to secure the additional funding that they require to commercialize their products.

Is This The Final Word? The law in this area can change nearly as quickly as the technology. It is possible that the Enzo decision will be modified, either by the Federal Circuit itself or by the Supreme Court. Even if the opinion stands as it is now, subsequent decisions by the Federal Circuit and other courts will provide further insight as to successful strategies for your situation.