The full bench of the Federal Circuit has recently rendered an opinion confirming that 35 U.S.C. § 112 has a separate written description requirement apart from the enablement requirement.  Ariad Pharmaceuticals, Inc. v. Eli Lilly and Co., No. 2008-1248, slip op. (Fed. Cir. March 22, 2010).  

The en banc court reaffirmed existing law, noting that "a separate requirement to describe one's invention is basic to patent law."  Ariad, at 12.  In rejecting Ariad's argument, it stated that "[c]laims define and circumscribe, the written description discloses and teaches."  Ariad, at 15.

With regard to functional claims that simply claim a desired result without claiming a species that achieves that result, the en banc court held that an adequate description "must demonstrate that the applicant has made a generic invention that achieves the claimed result and do so by showing that the applicant has invented species sufficient to support a claim to the functionally-defined genus."  Ariad, at 20.

The Written Description Requirement

The court began by considering various sources of law including the statutory language of 35 U.S.C. § 112 itself, Supreme Court precedent, as well as the decisions of its predecessor Court of Customs and Patent Appeals and its own prior decisions.  It then reached its conclusion that a written description requirement exists in the statute, separate from the enablement requirement.  Ariad, at 23.  It stated that the written description requirement extends beyond a priority context, such as in questions of new matter or whether claims are supported by a parent application, and is a requirement that even originally-filed claims must satisfy.  Ariad, at 22.

The court noted that claims covering multiple embodiments or species ("genus" claims) can lack written description if the specification does not disclose representative species or structural features common to the genus.  Ariad, at 21.  According to the court, this is an especially acute problem for functional claims that may simply claim a desired result, and may do so without describing species that achieve that result.  Ariad, at 20.

The previous Eli Lilly decision was referred to by the court in describing the issues relating to the written description requirement.  Ariad, at 21 (citing Regents of the University of California v. Eli Lilly & Co., 119 F.3d 1559 (Fed. Cir. 1997)). According to the court,

[W]e held that a sufficient description of a genus instead requires the disclosure of either a representative number of species falling within the scope of the genus or structural features common to the members of the genus so that one of skill in the art can “visualize or recognize” the members of the genus (emphasis added).
Ariad, at 21 (citing Eli Lilly, at 1568-69) (emphasis added).

Continuing, the court explained that adequate written description requires a precise definition, such as by structure, formula, chemical name, physical properties, or other properties, of species falling within the genus sufficient to distinguish the genus from other materials.  Ariad, at 21 (citing Eli Lilly, at 1568).  It also stated that functional claim language can meet the written description requirement when the art has established a correlation between structure and function.  Ariad, at 21 (citing Enzo Biochem, Inc. v. Gen-Probe Inc., 323 F.3d 956, 964 (Fed. Cir. 2002)).  The court declared that "merely drawing a fence around the outer limits of a purported genus is not an adequate substitute for describing a variety of materials constituting the genus and showing that one has invented a genus and not just a species."   Ariad, at 21.  Beyond citing its prior decisions, the court provided only little additional guidance to applicants seeking to ensure that their claims are supported by adequate written description.

The court did admit that the phrase "possession of the invention" was not very enlightening, and that "possession in the disclosure" is a more complete standard.  Ariad, at 24.  Accordingly, an "actual possession" or reduction to practice outside the specification is not enough to satisfy the written description requirement.  Ariad, at 25.  Further, the court held that reduction to practice is neither necessary nor sufficient.  Ariad, at 25.  The court did provide that the existence of working examples in the specification, or at least prophetic examples (i.e., a "thought experiment" that has not been performed) can be sufficient in establishing that written description support exists.   Ariad, at 35.  The court also stated that "a description that merely renders the invention obvious does not satisfy the requirement."  Ariad, at 25.  

For functional claims, the court asserted that the "written description requirement also ensures that when a patent claims a genus by its function or result, the specification recites sufficient materials to accomplish that function — a problem that is particularly acute in the biological arts."  Ariad, at 27.  The court expressed that functional claims will not satisfy the written description requirement when "[s]uch claims merely recite a description of the problem to be solved while claiming all solutions to it and … cover any compound later actually invented and determined to fall within the claim's functional boundaries — leaving it to the pharmaceutical industry to complete an unfinished invention."  Ariad, at 27.  

From this perspective, the court is not kind to basic research conducted by universities and institutions, even if that research is groundbreaking or necessary to the later patentable inventions of others.  Ariad, at 28.  The court acknowledged that universities may not have the resources or inclination to work out the practical end points of all such research, such as identifying target compounds.  Ariad, at 28.  Nonetheless, the court declared that the difficulty in obtaining patents to basic research is intentional: noting that patents "are not awarded for academic theories, no matter how groundbreaking or necessary to the later patentable inventions of others …, [as a patent] is not a reward for a search, but compensation for its successful conclusion."  Ariad, at 28.  It also declared that the written description requirement serves to limit "patent protection to those who actually perform the difficult work of 'invention' — that is, conceive of the complete and final invention with all its claimed limitations — and disclose the fruits of that effort to the public," and thus ensures that the public receives a meaningful disclosure in exchange for being excluded from practicing an invention for a period of time.  Ariad, at 28.

The Issues in This Case

Turning to the specific facts of Ariad, the court evaluated whether Ariad adequately described some way of performing the claimed methods.

An exemplary claim at issue in Ariad's U.S. Patent 6,410,516 ("the '516 patent") is claim 80, rewritten below to include the claims from which it depends:

80. [A method for modifying effects of external influences on a eukaryotic cell, which external influences induce NF-κB-mediated intracellular signaling, the method comprising altering NF-κB activity in the cells such that NF-κB-mediated effects of external influences are modified, wherein NF-κB activity in the cell is reduced] wherein reducing NF-κB activity comprises reducing binding of NF-κB to NF-κB recognition sites on genes which are transcriptionally regulated by NF-κB.
The parties agreed that the specification of the '516 patent suggested the use of the three classes of molecules to achieve NF-κB reduction: specific inhibitors, dominantly interfering molecules, and decoy molecules.  The court discussed each of the three disclosed classes of molecules used to achieve NF-κB reduction in the patent, and how the disclosure of such does not sufficiently describe the claimed invention, in that the specification did not "demonstrate that Ariad possessed the claimed methods by sufficiently disclosing molecules capable of reducing NF-κB activity so as to 'satisfy the inventor’s obligation to disclose the technologic knowledge upon which the patent is based, and to demonstrate that the patentee was in possession of the invention that is claimed.'"  Ariad, at 28 (citing Capon v. Esshar, 418 F.3d 1349, 1357 (Fed. Cir. 2005)).

Specific inhibitors block NF-κB binding to DNA in the nucleus. The court held that nearly all of Ariad's evidence regarding the disclosure of such a molecule, I-κB, relies upon figure 43, which was not disclosed until after the 1989 priority date.  The court discounted expert witness testimony that I-κB existed in 1989 and that one could isolate natural I-κB, stating that "a vague functional description and an invitation for further research does not constitute written disclosure of a specific inhibitor. … And it certainly does not constitute written disclosure of a method for reducing NF-κB activity using I-κB."  Ariad, at 33-34.

The specification described dominantly interfering molecules as truncated forms of NF-κB that would retain the DNA binding domain, but lack the RNA polymerase activating domain.  However, not only did the specification provide no example molecules of this class, but it also acknowledged that dominantly interfering molecules can work only if the DNA binding domain and the DNA polymerase domain of NF-κB are distinct regions in the NF-κB molecule.  The court concluded that because the inventors (who had discovered NF-κB) did not know if this were true at the relevant time, therefore "one of ordinary skill in the art was at best equally ignorant."  Ariad, at 34.  Thus, the court dismissed the dominantly interfering molecules as merely a wish or plan for future research, and therefore without adequate written description support.  Ariad, at 34-35.  The court considered it irrelevant that this teaching was later actually practiced.  Ariad, at 35.

Decoy molecules mimic a gene target of NF-κB so that NF-κB binds the decoy instead of its natural target.  Unlike the other two classes of molecules, the specification of the '516 patent proposed example structures of decoy molecules: it included a table of sequences recognized by NF-κB and a consensus sequence of the binding site (i.e., a common pattern among the sequences recognized by NF-κB).  Nonetheless, the court found the disclosure as a whole insufficient.  Ariad, at 35.  While the specification stated that NF-κB "would bind the decoy" to result in the desired negative regulation, the court was troubled by the lack of a "descriptive link between the table of decoy molecules and reducing NF-κB activity."   Ariad, at 35-36.  The court also noted that what descriptive support existed in the specification could not "bear the weight of the vast scope of these generic claims."  Ariad, at 37.

In view of the above, it appears that Ariad failed to properly describe the invention due to a lack of working examples demonstrating inhibition of NF-κB activity, or otherwise providing a descriptive link between certain disclosed molecules and the claimed functional activity.


This case serves to cement the existing precedent that a written description requirement exists in the patent statute and applies to original claims as well as amended claims.  Although Judges Linn and Rader wrote separate dissents-in-part wherein they disagreed with the majority's construal of the statute, the en banc decision remains the law.

Patent applicants may also view this case as a warning not to disclose planned research ideas in their patent applications if those ideas are insufficiently described to support claims, in that subject matter disclosed but not claimed in a patent application is placed in the public domain.  See Unique Concepts, Inc. v. Brown, 939 F.2d 1558, 1562-63 (Fed. Cir. 1991).

Further guidance on how the U.S. Patent and Trademark Office (USPTO) interprets the written description guidance can be found in the training materials available online (   We do not expect that the USPTO will make any substantial changes to this material in view of this recent decision.