Commentary: Federal Circuit enforces written description requirement even for negative limitations and narrower clai

In two recent decisions, different panels of the Federal Circuit reaffirmed the importance of the written description requirement of 35 U.S.C. § 112(a). These cases underscore the importance of the written-description requirement, and suggest that the Federal Circuit may be inclined to reject as invalid broad claims covering solutions to problems not described in the patent.

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In two recent decisions, different panels of the Federal Circuit reaffirmed the importance of the written description requirement of 35 U.S.C. § 112(a). In Novozymes A/S v. DuPont Nutrition Biosciences APS (Fed. Cir. 2013), the court held that, where a specification disclosed by a general description a large group of possible enzymes, later-filed claims for a particular species falling within the large group were not sufficiently described, even where each limitation in the claims was described, but not as combined in the claim. With In re Bimeda Research & Development Ltd. (Fed. Cir. 2013), the court found that a negative limitation in later-filed claims, carving out one agent, was not described in the original specification. In each case, the claims were held invalid on written description grounds.
These cases underscore the importance of the written-description requirement, and suggest that the Federal Circuit may be inclined to reject as invalid broad claims covering solutions to problems not described in the patent.
The Written-Description Requirement
The written description requirement arises from the patent statute, which requires that “[t]he specification shall contain a written description of the invention …” 35 U.S.C. § 112(a). In a previous en banc decision, the Federal Circuit held that the written description must convey that the inventor possessed the claimed subject matter as of the filing date. Ariad Pharm., Inc. v. Eli Lilly & Co. (Fed. Cir. 2010) stated that the test requires an objective inquiry into the four corners of the specification for proof of possession that is understandable to a person of ordinary skill in the art. 
Written description issues typically arise when later claims for an idea that is either broader or narrower than what is disclosed in a patent’s written description are added to a continuing application in order to capture what a competitor is doing.
Most prior cases concerned new claims that were broader than what the patent disclosed. For example, in LizardTech, Inc. v. Earth Resource Mapping, Inc. (Fed. Cir. 2005), the patent addressed an algorithm for creating “seamless DWTs” by “maintain[ing] updated sums” of DWT coefficients. A later-filed claim omitted the “maintain updated sums” limitations that were emphasized in the written description. The Federal Circuit held that the later claims were invalid for lack of written description, noting:
“The problem is that the specification provides only one method for creating a seamless DWT, which is to “maintain updated sums” of DWT coefficients…. Yet claim 21 is broader … because it lacks the “maintain updated sums” limitation…The trouble with allowing claim 21 to cover all ways of performing DWT-based compression processes that lead to a seamless DWT is that there is no support for such a broad claim in the specification. The specification provides only a single way of creating a seamless DWT, which is by maintaining updated sums of DWT coefficients. There is no evidence that the specification contemplates a more generic way of creating a seamless array of DWT coefficients.”
A similar conclusion was reached in ICU Med., Inc. v. Alaris Med. Sys., Inc. (Fed. Cir. 2009). In that case, the patent concerned medical valves having a body, a spike and a seal. Some later-added claims omitted the “spike” limitation. The Federal Circuit held those claims invalid because, based on the written description, “a person of skill in the art would not understand the inventor of the ‘509 and ‘592 patents to have invented a spikeless medical valve.”
Novozymes and Bimeda continue evolution of requirement
In Novozymes, patent-holder Novozymes developed alpha-amylase enzymes with greater stability in high-temperature and high-acidity environments. Novozymes identified 33 amino acid positions within seven different parent enzymes that would be susceptible to mutation, either through deletion, addition or substitution of amino acids, and that could be potential targets to create a mutated enzyme having greater stability. Novozymes then filed a provisional patent application disclosing the seven parent enzymes and the 33 amino acid positions. Novozymes also disclosed a number of examples of substitutions that could be made at these 33 positions which would provide an improved enzyme. Among the 33 positions, Novozymes identified position 239, and disclosed that by replacing a serine amino acid at that position with other amino acids, and in particular, tryptophan, an improved enzyme would be produced.
Defendant DuPont also researched alpha-amylase enzymes with greater stability, and eventually discovered a successful substitution by replacing serine at position 239 with glutamine. After seeing DuPont’s product, Novozymes filed a continuation application claiming an improved enzyme made by substituting serine at position 239. Specifically, all of the claims recited three limitations: (1) the specific enzyme, (2) the substitution at position 239 and (3) increased stability. At trial, DuPont argued that Novozymes’ patent was invalid for lack of written description. While the jury rejected this defense, the district court judge granted DuPont’s motion for judgment as a matter of law, finding that the claims were invalid for failing to satisfy the written description requirement.
A panel of the Federal Circuit affirmed the invalidity ruling. Judge Schall wrote the opinion for the court, joined by Judge Bryson. Importantly, the court looked to “the claims as a whole rather than as the sum of the individual limitations” in finding that Novozymes had not possessed the specific embodiment that it claimed. Although each of the individual limitations was disclosed in the specification, the specification did not disclose a single embodiment of an enzyme having all three limitations, “nor is there anything to suggest that Novozymes actually possessed such a variant at the time of filing.” Thus, the specification did not describe the “actual functioning [enzyme] that those limitations together define.”
Chief Judge Rader dissented, and opined that he was troubled by the “possession” standard for finding sufficient written description that emerged from Ariad. He also wrote that he believed substantial evidence supported the jury’s verdict.
Three days later, a separate Federal Circuit panel, consisting of Judges Clevenger, Prost and Chief Judge Rader, reached a similar conclusion in Bimeda. The patent in that case concerned methods for preventing the onset of bovine mastitis—inflammation of udder tissue in cows. The specification disclosed a composition for treating the teat canal without requiring the need for anti-infectives such as antibiotics. The specification referred to its “non-antibiotic approach” and explained that its method could be used to reduce the levels of antibiotics in food production. After the PTO ordered ex-parte reexamination of the original claims, the inventors sought claims for a method of controlling infections with “an acriflavine-free” formulation. Acriflavine was a well-known anti-infective agent. These claims would cover formulations containing anti-infective agents other than acriflavine.
The PTO rejected the new claims, and found them unsupported by the written description. The Federal Circuit affirmed, finding that the written description emphasized that the invention was a method that was free from all anti-infective agents. The written description did not support the exclusion of only one anti-infective agent—acriflavine—while still containing others. Acriflavine itself was never mentioned in the specification. “The … disclosure is therefore inconsistent with a claim which excludes acriflavine, but not the presence of other anti-infectives or antibiotics.” Thus, the panel held that the later-filed acriflavine-specific claims were invalid. Chief Judge Rader concurred with the result, but again expressed his reservations about the “possession” standard under the court’s written description case law.
Novozymes and Bimeda emphasize the role that the written description requirement plays when claims are narrower than what is described in general terms. In particular, even where all limitations of a claim may be described, but not as assembled in the claim, there is no written description. And even negative limitations must be described in the written description.
Chief Judge Rader’s concurring opinion in Bimeda suggests a different standard for finding cases invalid on written description grounds. Chief Judge Rader explained that the “possession” framework may not work “for all written description cases,” especially when negative limitations were involved, and stated that “the adequacy of written description must be determined on the facts of each case.” While finding no written description under the facts of Bimeda, he did not agree that negative limitations in general needed to be disclosed. Even though acriflavine was never mentioned in the patent, Judge Rader pointed out that “[a]criflavine was a well-known species of anti-infective that had been used in teat seals to treat bovine mastitis for over 75 years.” This statement suggests that Judge Rader would include certain kinds of knowledge in the art outside the patent in his written description analysis.
Practitioners would be well-served to keep abreast of the Federal Circuit’s evolving jurisprudence regarding the written description requirement, especially regarding what information outside a patent may be allowed to support a written description in some future cases.

Dr. Stuart E. Pollack is a partner in DLA Piper’s Patent Litigation group, based in New York. He concentrates his practice on patent litigation as well as patent prosecution and patent counseling and opinion work. With extensive trial experience in federal court, Pollack has helped obtain favorable judgments in several suits on behalf of pioneer drug companies, including suits brought under the Hatch-Waxman Act against potential generic entrants.
Nika Aldrich is a litigator who covers intellectual property as well as commercial law, international law and bankruptcy. Before joining DLA Piper, Mr. Aldrich worked at the World Intellectual Property Organization’s offices at the United Nations, where he attended Security Council and General Assembly meetings, studied the effects of global intellectual property regimes on developing nations and wrote about the intersection of the United Nations Millennium Goals with international intellectual property systems.

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