What Does § 112 Require? Federal Circuit to Clarify the "Written Description" Requirement

24 August 2009 Publication
Author(s): Jeanne M. Gills

Legal News Alert: IP Litigation

On Friday August 21, 2009, the Federal Circuit indicated that it would address a long-standing intra-circuit split on a fundamental question of patent law. The Court issued an order vacating its opinion in Ariad Pharmaceuticals, Inc. v. Eli Lilly & Co., 560 F.3d 1366 (Fed. Cir. 2009), and requesting additional briefing addressing the following questions:

  1. Whether 35 U.S.C.§ 112, paragraph 1, contains a written description requirement separate from an enablement requirement?
  2. If a separate written description requirement is set forth in the statute, what is the scope and purpose of the requirement?


By agreeing to address these questions en banc, the Federal Circuit will resolve a dispute that has prompted repeated, vigorous intra-circuit dispute. See, e.g., Univ. of Rochester v. G.D. Searle & Co., 375 F.3d 1303 (Fed. Cir. 2004) (Newman, J.; Rader, J.; Gajarsa, J.; Linn, J., dissenting from denial of rehearing en banc); Moba B.V. v. Diamond Automation, Inc., 325 F.3d 1306 (Fed. Cir. 2003); Enzo Biochem, Inc. v. Gen-Probe Inc., 323 F.3d 956 (Fed. Cir. 2002) (Rader, J.; Gajarsa, J.; Linn, J. dissenting from denial of rehearing en banc).

Section 112 requires that:

The specification shall contain 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, and shall set forth the best mode contemplated by the inventor of carrying out his invention.

35 U.S.C. § 112, ¶ 1.

Prior to 1997, the Federal Circuit had interpreted this provision as imposing three requirements on a patent’s specification:

  1. The specification must contain a description that enables others to make and use the claimed invention (the “enablement” requirement)
  2. The specification must describe the best mode contemplated by the inventor (the “best mode” requirement)
  3. The specification must be sufficiently complete and detailed that it conveys to those skilled in the art that, as of the filing date, the inventor was in possession of the invention (the “possession” requirement)


Beginning with Regents of the University of California v. Eli Lilly & Co., 119 F.3d 1559 (Fed. Cir. 1997), the Federal Circuit further interpreted § 112 as imposing an additional, broader disclosure requirement. This expanded written description requirement arguably is a rigorous application of the possession requirement. Using this expanded test, courts have invalidated broad claims in a number of cases involving a variety of technologies. See, e.g., Univ. of Rochester v. G.D. Searle & Co., 358 F.3d 916 (Fed. Cir. 2004); Gentry Gallery, Inc. v. Berkline Corp., 134 F.3d 1473 (Fed. Cir. 1998).

Proponents of expanding the written description requirement in this manner argue that it is necessary to prevent applicants who write specifications with broad, generic disclosures from obtaining broad claims that cover things not within the inventor’s conception of the invention at the time of filing. This need is especially acute in the case of claims that are added to an application long after the original filing date, but which seek benefit of that early date.

Opponents argue that the application of this expanded written description test has severely and unduly limited the scope of claim coverage. Opponents argue that, as applied, this test has rendered unpatentable any claim that goes beyond the specific embodiments described in the specification. This development has prompted applicants to file voluminous applications, with specifications that run for hundreds of pages. It is the opponents’ view that the enablement requirement is sufficient to limit the permissible scope of claims based on a particular specification.

For more than a decade, the Federal Circuit has suffered from an internal split regarding the standards that must be met for a patent’s specification to comply with 35 U.S.C. § 112. The resolution of this dispute will affect the way patent specifications are written in every technical area. This case, therefore, will be closely followed and is likely to attract extensive participation by third parties as amicus curiae.


Legal News Alert is part of our ongoing commitment to providing up-to-the-minute information about pressing concerns or industry issues affecting our clients and our colleagues. If you have any questions about this update or would like to discuss this topic further, please contact your Foley attorney or the following:


George C. Best
Palo Alto, California

Sharon R. Barner
Chair, Intellectual Property Department
Chicago, Illinois

Jeanne M. Gills
Vice Chair, IP Litigation Practice
Chicago, Illinois

Larry L. Shatzer
Chair, IP Litigation Practice
Washington, D.C.

Jeffrey A. Simmons
Madison, Wisconsin