The written description requirement of 35 U.S.C. Section 112 is recognized as a serious threat to patent validity in the “unpredictable arts,” such as chemistry and biology. The United States Court of Appeals for the Federal Circuit has frequently invalidated pioneering claims from the “unpredictable arts” for failing to satisfy the written description requirement. See Regents of the Univ. of California v. Eli Lilly & Co., 119 F.3d 1559 (Fed. Cir. 1997); Univ. of Rochester v. G.D. Searle & Co., Inc., 358 F.3d 916 (Fed. Cir. 2003). Practitioners in the “predictable arts,” such as mechanical, electrical and software engineering, are often less familiar with the pitfalls of the written description requirement because it has had a less dramatic impact on their fields. However, the Federal Circuit has invalidated claims from the “predictable arts” for failing to satisfy the written description requirement with increasing frequency. These decisions may suggest to practitioners in the predictable arts that the written description requirement deserves their attention.

Written Description 101

The Patent Act requires that the specification of a patent 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 . . . .

35 U.S.C. § 112 ¶ 1 (emphasis supplied). The Federal Circuit has developed a doctrine holding that that §112 ¶ 1 of the Patent Act contains two separate and distinct requirements: a requirement that the specification enable a person skilled in the art to make and use the invention (the enablement requirement), and a requirement that the specification contain a written description of the invention (the written description requirement). Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d. 1336, 1340 (Fed. Cir. 2010). To satisfy the written description requirement, the specification must reasonably convey to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date.” Id. at 1351. Possession is shown from the disclosure, and “the test requires an objective inquiry into the four corners of the specification from the perspective of a person of ordinary skill in the art.” Id.

Prosecution Strategies

Those involved in the drafting and prosecution of patent applications may find it helpful to consider the following strategies to minimize the risk of written description problems undermining the claims during future litigation. First, it may be helpful to describe critical elements of the invention with many embodiments and conclude with a statement that describes the general function of the element. For example, one may describe a fastener as “staples, nails, screws, tape, glue, or any other material or element suitable to attach A to B.” Disclosure of multiple embodiments may often be helpful to a court’s finding that the specification satisfies the written description requirement with respect to a particular claim. See Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (holding that the written description requirement was satisfied for claims that were not restricted to achieving all the disclosed objectives because “the fact that the [specification] sets forth multiple objectives to be served by the baffles . . . confirms that the term ‘baffles’ should not be read restrictively to require that the baffles in each case serve all of the recited functions”).

Second, it may be advantageous to minimize characterizing the invention, the prior art, the claims, or disclosing more than is necessary to comply with the statutory requirements for patentability and advance prosecution. One example of such a strategy may be a policy of limiting statements in responses to Office Actions, or in Examiner Interviews, relating to the specification, the prior art and the claims to quotations from the application to avoid unhelpful-characterization or unhelpful paraphrasing of the claims. The Federal Circuit has frequently used characterizations of the invention or the prior art from the specification and prosecution history to invalidate claims under the written description requirement. See, Tronzo v. Biomet, Inc., 156 F.3d 1154 (Fed. Cir. 1998) (holding that the written description requirement was not satisfied for claims covering non-conical cup implants for an artificial hip when the specification emphasized advantages of conical shape over other prior art shapes); Mukherjee v. May-Ying Chu, 217 Fed. Appx. 971 (Fed. Cir. 2007) (holding that the written description requirement was not satisfied for claims covering battery cathodes without an electroactive transition metal chalcogenide (“ETMC”) when the specification criticized non-ETMC cathodes in the prior art and disclosed that the cathodes of the invention contained ETMC “in all cases”); Gentry Gallery v. Berkline Corp., 134 F.3d 1473 (Fed. Cir. 1998) (holding that the written description requirement was not satisfied for claims that did not limit the location of a sofa control console when the specification disclosed only one location for a sofa control console and the inventor admitted at trial that he had not thought of alternate locations for a control consol until after he saw competitors’ products).

Third, there is no good reason to characterize what “the invention” is, includes, or covers — this is the purpose of the claims, as properly construed by an Examiner or Judge. Unnecessary discussion of “the invention” or the nature or quantum of its improvement on the prior art, without reference to a particular claim, may inadvertently support limiting the issued claims to particular exemplary embodiments. As with most legal matters, it will also rarely be accurate or safe to use absolute or limiting words such as only, require, must, shall, all, necessary, critical, or essential. A court might use these words, if included in the specification and/or file history, during claim construction to limit the scope of claims to a single embodiment, or to limit the claims in a manner not intended by the drafter. See Mukherjee v. May-Ying Chu, 217 Fed. Appx. 971 (Fed. Cir. 2007) (holding that the written description requirement was not satisfied for claims covering non-ETMC battery cathodes when the specification stated that ETMC cathodes were “critical” and were used “in all cases”). Finally, when possible, patentees will want to consider including language that notes that the disclosed embodiments are exemplary, and not intended to limit the scope of the invention to only the disclosed embodiments. For example, an ending paragraph in the specification of a patent may read: “Although the present invention has been described with several embodiments, a multitude of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes, variations, alterations, transformations, and modifications as fall within the scope of the appended claims.”

Litigation Strategies

In litigation, the written description requirement can, in appropriate circumstances, be a powerful tool for defendants to invalidate or narrow claims asserted against them. Defendants will generally investigate the embodiments disclosed in the specification and identify any common elements that are not included in the asserted claims. The Federal Circuit has, in certain instances, invalidated claims that did not contain an essential element common to all disclosed embodiments for failing to satisfy the written description requirement because persons skilled in the art would not recognize from the specification that the inventor had invented embodiments without the common element. See LizardTech, Inc. v. Earth Resource Mapping, 424 F.3d 1336 (Fed. Cir. 2005) (holding that the written description requirement was not satisfied when all embodiments in the specification disclosed performing seamless discrete wavelet transforms (“DWTs”) by maintaining updated sums, but the claims were not restricted to performing seamless DWTs by maintaining updated sums); ICU Medical, Inc. v. Alaris Medical Systems, Inc., 558 F.3d 1368 (Fed. Cir. 2009) (holding that the written description requirement was not satisfied when all embodiments in the specification disclosed medical valves with spikes, but claims covered medical valves without spikes).

Thorough defendants will also search the specification and prosecution history for limiting words and statements that can be used to narrow the scope of the claims. See Mukherjee v. May-Ying Chu, 217 Fed. Appx. 971 (Fed. Cir. 2007) (holding that the written description requirement was not satisfied for claims covering non-ETMC battery cathodes when the specification stated that ETMC cathodes were “critical” and used “in all cases”); McMullin v. Carroll, 153 Fed. Appx. 738 (Fed. Cir. 2005) (holding that the written description requirement was not satisfied for claims that did not limit the angle of a cleat protrusion when the specification disclosed that the cleat protrusion could range from 5° inward to 15° outward”).

Even if these strategies do not succeed in invalidating a claim, they may effectively pressure the plaintiff to narrow its asserted claim scope to avoid risking invalidity and may convince a court to adopt a narrower claim construction than patentee is seeking.