Last Month at the Federal Circuit
Last Month at the Federal Circuit

April 2010

En Banc Court Confirms Existence of Written Description Requirement Separate from Enablement


Judges:  Michel, Newman (additional views), Mayer, Lourie (author), Rader (dissenting-in-part, concurring-in-part), Bryson, Gajarsa (concurring), Linn (dissenting-in-part, concurring-in-part), Dyk, Prost, Moore
[Appealed from D. Mass., Judge Zobel]

In Ariad Pharmaceuticals, Inc. v. Eli Lilly & Co., No. 08-1248 (Fed. Cir. Mar. 22, 2010) (en banc), the Federal Circuit held en banc that 35 U.S.C. § 112 contains a written description requirement separate from enablement. 

Ariad Pharmaceuticals, Inc., Massachusetts Institute of Technology, the Whitehead Institute for Biomedical Research, and the President and Fellows of Harvard College (collectively “Ariad”) sued Eli Lilly & Company (“Lilly”), alleging infringement of U.S. Patent No. 6,410,516 (“the ’516 patent”).  The ’516 patent relates to the regulation of gene expression by the transcription factor NF-κB.  The claims in the  ’516 patent are genus claims, encompassing the use of all substances that achieve the desired result of reducing the binding of NF-κB to NF-κB recognition sites.

At trial, a jury found infringement, and found none of the asserted claims invalid.  A Federal Circuit panel reversed the district court’s denial of Lilly’s motion for JMOL and held the asserted claims invalid for lack of written description, but upheld the district court’s finding of no inequitable conduct.  Ariad petitioned for rehearing en banc, challenging the existence of a written description requirement separate from the enablement requirement.


“If Congress had intended enablement to be the sole description requirement of § 112, first paragraph, the statute would have been written differently.” Slip op. at 11.

A case involving statutory interpretation, the Court began with the language of the statute itself.  The Court agreed with Lilly and read the statute to give effect to its language that the specification “shall contain a written description of the invention,” and held that § 112, first paragraph, contains two separate description requirements:  a “written description [i] of the invention, and [ii] of the manner and process of making and using [the invention].”  Slip op. at 10 (alterations in original) (citing 35 U.S.C. § 112, ¶ 1).  The Court held that if Congress had intended enablement to be the sole description requirement of § 112, first paragraph, the statute would have been written differently. 

The Court held that a separate requirement to describe one’s invention is basic to patent law.  The specification must then, the Court explained, describe how to make and use the invention (i.e., enable it), but that is a different task. 

The Court also read Supreme Court precedent as recognizing a written description requirement separate from an enablement requirement.  The Court held that a separate written description requirement also does not conflict with the function of the claims.  The Court noted that claims define and circumscribe, while the written description discloses and teaches.

In addition to the statutory language and Supreme Court precedent supporting the existence of a written description requirement separate from enablement, stare decisis impelled the Court to uphold it.  To change course now, according to the Court, would disrupt the settled expectations of the inventing community, which has relied on it in drafting and prosecuting patents, concluding licensing agreements, and rendering validity and infringement opinions.  The Court explained that if the law of written description is to be changed, such a decision would rest with Congress.

The Court rejected Ariad’s argument that original claims, as part of the original disclosure, constitute their own written description of the invention.  Although many original claims will satisfy the written description requirement, certain claims may not.  For example, a generic claim may define the boundaries of a vast genus of chemical compounds, and yet the question may still remain whether the specification, including original claim language, demonstrates that the applicant has invented species sufficient to support a claim to a genus.  The problem is especially acute with genus claims that use functional language to define the boundaries of a claimed genus.  In such a case, the functional claim may simply claim a desired result and may do so without describing species that achieve that result.  But the specification 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.

In fact, the Court held, this case illustrates the problem of generic claims.  The claims in this case recite methods encompassing a genus of materials achieving a stated useful result, i.e., reducing NF-κB binding to NF-κB recognition sites in response to external influences.  But the specification does not disclose a variety of species that accomplish the result.

The Court recognized that there may be little difference in some fields between describing an invention and enabling one to make and use it, but that is not always true of certain inventions, including chemical and chemical-like inventions.  Thus, although written description and enablement often rise and fall together, requiring a written description of the invention plays a vital role in curtailing claims that do not require undue experimentation to make and use, and thus satisfy enablement, but that have not been invented, and thus cannot be described.  For example, a propyl or butyl compound may be made by a process analogous to a disclosed methyl compound, but, in the absence of a statement that the inventor invented propyl and butyl compounds, such compounds have not been described and are not entitled to a patent.  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.

Adopting the analysis of the original panel, the Court concluded that the asserted claims of the ’516 patent are not supported by a written description because the specification of the ’516 patent fails to adequately disclose how the claimed reduction of NF-κB activity is achieved.  The Court held that the ’516 patent discloses no working or even prophetic examples of methods that reduce NF-κB activity and no completed syntheses of any of the molecules prophesized to be capable of reducing NF-κB activity.  The state of the art at the time of filing was primitive and uncertain, leaving Ariad with an insufficient supply of prior art knowledge with which to fill the holes in its disclosure.  The specification, the Court held, at best describes decoy molecule structures and hypothesizes with no accompanying description that they could be used to reduce NF-κB activity.  Yet, the asserted claims are far broader.  The Court therefore concluded that the jury lacked substantial evidence for its verdict that the asserted claims were supported by adequate written description and thus held the asserted claims invalid.  The Court also reinstated Part II of the panel decision, affirming the district court’s finding of no inequitable conduct.


“Finally, a separate requirement to describe one’s invention is basic to patent law.  Every patent must describe an invention.  It is part of the quid pro quo of a patent; one describes an invention, and, if the law’s other requirements are met, one obtains a patent.  The specification must then, of course, describe how to make and use the invention (i.e., enable it), but that is a different task.” Slip op. at 12.

Judge Newman joined the majority but wrote separately to add that the subject matter of this case was basic research, which was taken to the patent system before its practical application was demonstrated.  In Judge Newman’s view, the threshold in all cases requires a transition from theory to practice.

Judge Gajarsa concurred, writing that in his view, the text of § 112, ¶ 1, is a model of legislative ambiguity.  He found the majority’s interpretation of the statute reasonable but disagreed that an independent written description requirement is a necessity of patent law.  Judge Gajarsa explained that empirical evidence demonstrates that written description serves little practical purpose as an independent invalidity device, and better serves the goals of the Patent Act when confined to the priority context.  He concluded that confining written description to the priority context would provide greater clarity to district courts and practitioners, “both of whom are currently left to trudge through a thicket of written description jurisprudence that provides no conclusive answers and encourages a shotgun approach to litigation. . . . [O]nly Congress wields the machete to clear it.”  Gajarsa Dissent at 4.

Judge Rader, with whom Judge Linn joined, dissented-in-part and concurred-in-part.  Judge Rader concluded that the statute is unambiguous and has no separate written description requirement.  Judge Rader stated that a proper reading of the statutory description requirement recognizes that the enablement requirement identifies the invention and tells a person of ordinary skill what to make and use.  Further, he concluded that the written description doctrine only has meaning if the Court ignores its own claim construction rules.  That is, according to Judge Rader, the Court gets power to err twice―both in construing the claims so broadly as to exceed the scope of the rest of the specification and then to invalidate those claims because it reads the specification as failing to support the Court’s own broad conception of the claimed subject matter.

Judge Linn, with whom Judge Rader joined, also wrote separately to dissent-in-part and concur-in-part.  Judge Linn wrote that the statutory arguments fail to justify establishing a separate written description requirement apart from enablement and beyond the priority context, and fail to tether that written description requirement to a workable legal standard.  He believed the appeal should have been returned to the panel for resolution of the enablement question, but concurred in the affirmance of no inequitable conduct.