I. Introduction

In United States patent law, in addition to satisfying the requirements for subject-matter eligibility, novelty, enablement, definiteness, and nonobviousness, a patent must comply with the written description requirement as specified in 35 U.S.C. §112. This means that the specification must contain a written description of the invention, in full, clear, concise and exact terms so that a person of skill in the art would be able to make and use the invention. 35 U.S.C. §112. Written description is an issue of fact, which is resolved on a case-by-case basis.

The requirements for written description are in 35 U.S.C. §112. Written description is a key issue in many parts of patent prosecution and litigation, including reissue (35 U.S.C. §251) and reexamination (35 U.S.C. §132), such as whether newly introduced terms or content to the specification are "new matter." In modern practice, unpatentability based on 35 U.S.C. §112 can be a ground of unpatentability in post-grant reviews ("PGRs"), but not in inter partes reviews ("IPRs"). Compliance with 35 U.S.C. §112 may arise in IPRs in establishing entitlement to priority dates of both references and challenged patents. Section 112 also arises in post-grant proceedings in the context of proposed substitute amendments. See 35 U.S.C. §316(d)(3) and §326(d)(3). And Section 112, written description, is taking center stage these days in litigation, as witnessed by the several pending petitions for certiorari.1

While modern case law continues to expand our understanding of written description, it is important to consider United States Court of Customs and Patent Appeals ("CCPA") cases, and how these decisions shaped and continue to influence current patent law jurisprudence. Between 1963 and 1982, the CCPA issued multiple decisions concerning written description. The vast majority of these decision have not been overruled by the CCPA or overturned by an en banc Court of Appeals for the Federal Circuit ("CAFC") and thus remain binding precedent. See South Corp. v. U.S., 690 F.2d 1368, 1369 (Fed. Cir. 1982). Notably, many involved appeals from ex parte prosecution and are still found throughout the Manual of Patent Examining Procedure ("MPEP") and, therefore, may be especially useful in responding to examiner rejections. This article summarizes key CCPA written description decisions that, remaining binding precedent, should be considered to enhance the chances that your patents are in compliance with the written description requirement.

II. Case Summaries

A. In re Oda, 443 F.2d 1200 (C.C.P.A. 1971)

In In re Oda, the invention was directed to certain phthalides useful as intermediates for conversion into basic dyes and pressure-sensitive copying papers. The application for the original patent was prepared by translating the corresponding Japanese applications filed in May 1960 and July 1962 into English. Id. at 1201. The most important error was that "nitric acid" was mistranslated as "nitrous acid." Id. Applicant's patent attorney knew of the error before the patent issued and thought the errors could be corrected by an amendment, but the examiners recommended against and refused entry. Id. Four months after issuance, applicants thought the errors would affect its validity and filed for a reissue application. Id.

In the specification, the word "nitrous" was changed to "nitric" in three different instances. The reissue Examiner rejected Claims 1-3 under 35 U.S.C. §251 as being based on a specification containing new matter and thus not satisfying the written description requirement. Id. at 1202. The Board affirmed.

On appeal, the Court stated that the reissue statute was based on principles of equity and fairness, as a remedial provision to help applicants out of difficult situations, wherein there was no "deceptive intent." Id. at 1203.2 The Court stated that the determination of "new matter" is done on a case-by-case basis, and that the change from nitrous to nitric acid occurs only in the description of how to make the claimed compounds, which is not the invention, since the process is not claimed. Id. at 1205. The Court further stated that the reaction in which "nitrous acid" is stated is a well-known reaction and a person of skill in the art would know that the acid was misnamed. Id. The Court reversed the Board and the examiner, finding that there were numerous instances and evidences to show that the change from "nitric" to "nitrous" originated from a translation error and that its correction was not the introduction of new matte, Id. at 1205-06 and thus did not violate the written description requirement.

B. In re Gardner, 475 F.2d 1389 (C.C.P.A. 1973)

In In re Gardner, the invention was directed to a class of guanidinoalkyl-1:4-benzodioxan compounds which are useful as antihypertensive agents. Independent Claim 2 was directed to a general genus of compounds, comprising a substituent group R1, where R1is a "member of the group consisting of hydrogen, methyl, methoxy, chlorine and bromine." Id. at 1390. The examiner rejected the claims under 35 U.S.C. §112, stating that the independent Claim 2 was "too broad" in view of the lack of support in the specification for all the compounds encompassed by the substituent group R1and the floating positions thereof. Id. The examiner also emphasized the lack of showing that all the compounds possess the asserted utility. Id. The Board affirmed the examiner's rejection.

The Court highlighted that the issues lie in whether the "separate but related description and how-to-use requirements of the first paragraph of 35 U.S.C. §112 have been satisfied." Id. at 1391. The Court found that only three of the five possible R1substituents were specifically exemplified but held that there was no need for either additional representative examples or more definite language to satisfy the description requirement. Id. The Court held that Independent Claim 2, as an original claim, itself constituted a description in the original disclosure equivalent in scope, and that nothing more is necessary for compliance with the description requirement of 35 U.S.C. §112. Regarding the "how-to-use" issue, the Court clarified that the "how-to-use" requirement of 35 U.S.C. §112 is not based on the utility requirement of 35 U.S.C. §101. Id. at 1392. However, the Court stated that the absence of the asserted utility may lead to a rejection under either statute, and that the standard to be applied is the absence of utility. Here, the Court held that there is no requirement in 35 U.S.C. §112 that all the claimed compounds have the same degree of utility, just that they have some utility. Id. Therefore, the Court reversed the Board's decision that the claims did not satisfy the description and "how-to-use" requirements of 35 U.S.C. §112.

C. In re Smythe, 480 F.2d 1376 (C.C.P.A. 1973)

In In re Smythe, the invention was directed to an analysis system wherein discrete liquid samples, containing blood or other body fluids are introduced into an apparatus as a continuous stream, where the individual samples are separated by a medium, which as originally claimed and taught by the specification is "air or other gas which is inert to the liquid" sample transmitted. Id. at 1377. The claims on appeal were directed to both method and apparatus. Id. The claims were rejected under 35 U.S.C. §112 for failing to describe the invention based on the term "inert fluid," since the claims refer to air or other gas transmitted as the analysis samples. Id. at 1378. The claims were additionally rejected under 35 U.S.C. §112 because the specification did not enable one skilled in the art to use an "inert gas" as a segmentizing medium in the invention. Id. The Board affirmed.

The Court stated that the "medium" that separates the samples takes the shape of the supply lines and flow cell through which it passes, making it precisely a "fluid" and a "liquid." Id. at 1383. The Court held that the use of an "inert fluid" broadly in the claimed invention would naturally occur to one skilled in the art and that this is not a case where there is any unpredictability such that appellants' description of air or other inert gas would not convey to one skilled in the art that the appellants invented an analysis system where a fluid medium segmented the samples. Id. The Court reversed the Board's rejection regarding the term "inert fluid." Id. at 1385. Regarding the rejection because of the term "inert gas," the Court held that the "inert gas" covers the use of gases other than air, reversing the Board's rejection as well. Id. at 1386.

The Court in Smythe has some very good language that may be helpful for patent applicants in overcoming rejections for lack of written description:

We cannot agree with the broad proposition...that in every case where the description of the invention in the specification is narrower than that in the claim there has been a failure to fulfill the description requirement in section 112. Each case must be decided on its own facts. The question which must be answered is whether the application originally filed in the Patent Office clearly conveyed in any way to those skilled in the art, to whom it is addressed, the information that appellants invented the [claimed subject matter]. . . .If it did, then appellants have made a written description of their invention within the meaning of the first paragraph of 35 U.S.C. §112.

Id. at 1382.

D. In re Johnson, 558 F.2d 1008 (C.C.P.A. 1977)

In In re Johnson, the invention at issue related to a linear thermoplastic polyarylene polyether polymers composed of recurring units having the general formula "O-E-O-E'", where "O" represents an oxygen atom, "E" represents the residuum of a dihydric phenol compound, and E' represents the residuum of a benzenoid compound. The invention was disclosed in a continuation application ("the 1972 application"), which described a method of synthesis for the polymers and included disclosure regarding the electron withdrawing group in E' and in the E' precursor compound. Id. at 1009-10. The application to which the 1972 application claims priority is called "the 1963 application" and describes the genus of polymers in the 1972 application, and the identity of the E and E' precursor compounds. Id. at 1011.

The examiner and the Board were of the view that the claims of the 1972 application were not entitled to the priority date of the 1963 application because the claimed subject matter was not "described" in the 1963 application as required by 35 U.S.C. §112. Id. at 1014. The examiner also rejected claims 64, 68-72 under the first paragraph of 35 U.S.C. §112 for being "broader than the enabling disclosure" and under the second paragraph of 35 U.S.C. §112 for being "broader than the express limitations disclosed as defining the invention." Id. at 1015. The Board affirmed.

The Court reversed the Board and the examiner, holding one of ordinary skill in the art would be able to determine from appellants' specification what level of activation is necessary to practice the invention. Id. at 1016. Therefore, the subject matter disclosed in claims 64, 68-72 is definite, and the claims set out and circumscribe a particular area with a reasonable degree of precision and particularity. The Court further held that the specification as a whole must be considered in determining whether the scope of enablement is commensurate with the scope of the claims. Based on this reasoning, the Court reversed the Board's and the examiner's rejection of the claims under the first paragraph of 35 U.S.C. §112. Lastly, the Court held that the invention recited in claim 1 of the 1972 application is disclosed in the 1963 application, and therefore the 1972 application was entitled to the priority date of the 1963 application. Id. at 1017. In other words, there was written description in the 1963 application of the invention claimed in the 1972 application.

E. In re Rasmussen, 650 F.2d 1212 (C.C.P.A. 1981)

In In re Rasmussen, the invention in the original application was directed to a method of manufacturing a thermal insulating member. The applicant later amended the independent claim by substituting the phrase "adheringly applying" to specify the use of adhesives. Id. at 1213. The examiner rejected the term "adheringly applying," saying that it was "new matter" under 35 U.S.C. §132 and would be an allowance of an improperly broader claim, enlarging the scope of the disclosure. Id. at 1214. The Board affirmed.

The Court stated that the proper basis for a rejection of a claim amended to recite elements thought to be without support in the original disclosure is 35 U.S.C. §112 and not as new matter under 35 U.S.C. §132. Id. The Court held that the amended claim term "adheringly applying" is described within the specification and that a claim may be broader than the specific embodiment disclosed in a specification. Id. at 1215. Therefore, since the term 'adheringly applying" is supported by the example found in the specification, the Court reversed the ruling by the Board and the examiner.

III. Conclusion

The cases discussed above only scratch the surface of CCPA precedents regarding written description in United States patent law. It is important to remember that CCPA cases provided a foundation, and they continue to provide useful analyses and arguments to use in modern patent law practice. Compliance with the written description requirement of §112 must be analyzed from the point of view of what one of ordinary skill in the art would understand and that cannot be overlooked by an examiner or a challenger, particularly if the specification or perhaps declaration testimony establishes that point of view. Of course, any time a declaration is employed, one must take care not to file false information or even incomplete information with a specific intent to deceive the USPTO.

The CCPA may be gone—but the Court and its decisions should not be forgotten.


1. See, e.g., Juno Therapeutics, Inc. v. Kite Pharma, Inc., pet. for cert., No. 21-1566, filed June 13, 2022; Biogen Int'l GmbH v. Mylan Pharms. Inc., pet. for cert., No. 21-1567, filed June 14, 2022; and Amgen Inc. v. Sanofi, pet. for cert., No. 21-757, filed Nov. 22, 2021.

2. Note, 125 Stat. 284 – the Leahy-Smith America Invents Act removed the phrase "without deceptive intention" from 35 U.S.C. §251, effective Sept. 16, 2012.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.