Written Description Precludes Fishing Expedition

July 22, 2013

What This Means To You

  • For prophetic embodiments, provide a rationale for why such embodiments are beneficial to support a claim to possession if challenged.
  • Understand the potential weakness for patent claim limitations that are based on prophetic examples.


In its decision in Novozymes v. DuPont Nutrition Biosciences, the U.S. Court of Appeals for the Federal Circuit (Federal Circuit) upheld the current written description standard.

Case Background

Two competitors, Novozymes and Danisco (later acquired by DuPont), were both involved in the research and development of thermostable bacillus alpha amylase strains designed to be useful in various manufacturing processes and products, such as sugar refining, ethanol production, and detergent formulations.

In July 2001, Novozymes filed a non-provisional patent application generically directed to thermostable variants of bacillus alpha amylases, such as B. sterothermophilus (BSG) and B. licheniformis (BLA), with a primary focus on the BLA strain. Novozymes’ application teaches 17 predicted mutable positions (based on rational protein design) and 16 experimentally identified mutable positions (based on random mutagenesis) of bacillus alpha amylase to provide thermostable variants.

The application provided two examples with empirical data confirming the enhanced stability of the mutants harboring the 16 mutations identified by random mutagenesis. No data were disclosed regarding the thermostability of any of the 17 positions predicted by rational protein design.

In November 2008, Danisco filed a non-provisional application directed to thermostable variants of BSG, disclosing 1500 different variants, and specifically identifying the mutant serine 239 glutamine (S239Q) as the best performer. Thereafter, Danisco began marketing this S239Q mutant as the biofuel product GC 358.

In December 2009, Novozymes attempted to cover Danisco’s S239Q product by filing a continuation application claiming an isolated variant of a parent alpha-amylase wherein: (a) the variant has at least 90% sequence identity to the BSG alpha-amylase enzyme; (b) the variant comprises a substitution of serine at position 239 relative to the parent alpha amylase, using the BLA sequence to determine position numbering; and (c) the variant has increased thermostability relative to the parent alpha-amylase.

Each of the limitations claimed was specifically recited in the application as filed. The key limitations, namely the BSG enzyme and the mutation at position 239, were each provided in separate listings in different parts of the specification. In May 2010, the U.S. Patent and Trademark Office (USPTO) granted U.S. Patent No. 7,713,723 (the ‘723 patent) reciting this claim.

Novozymes filed suit against DuPont (formerly Danisco) in the Western District of Wisconsin asserting the ‘723 patent, and trial ensued. After a jury found for Novozymes, awarding $18M in damages, Danisco filed a motion for judgment as a matter of law (JMOL) against this verdict.

The District Court reversed the jury decision, and held the ‘723 invalid for lack of written description. Novozymes appealed the JMOL order to the Federal Circuit.

Decision Analysis

The Federal Circuit affirmed the district court’s judgment after determining the specification only provided generalized guidance, listing several variables (e.g., BSG and S239) that might, taken in some combination, lead to a useful result.

In particular, the Court pointed to the variable S239, which was provided in a listing of other possible positions for mutations, each predicted by rational protein design and not supported by any rationale for the mutation or by empirical data.

Viewing the claims as an integrated whole rather than a collection of independent limitations, the Court did not see any “blaze marks” in the application that would confirm Novozyme had possession of the claimed invention at the time of filing, a flaw rendering the ‘723 patent invalid for lack of written description.


For prophetic embodiments – such as Novozymes’ mutant S239 – provide a rationale for why such embodiments are beneficial to support a claim to possession if challenged. For example, if Novozymes had explained in the application why the predicted position S239 was of particular interest, rather than merely listing S239 with other predicted mutable positions, the patent would more likely have satisfied the written description requirement.

Furthermore, if attempting to cover a competitor product, beware of casting “too wide a net” when drafting claims. For example, Novozymes’ efforts to cover Danisco’s product were viewed as over-reaching, especially because Novozymes’ application did not appear to recognize the specific combination of elements claimed.