Inherency Rejections: Combating Inherent Obviousness

By Gene Quinn
October 24, 2017

inherentNot only may express disclosures of a prior art reference be relied upon by a patent examiner when rejecting claims under 35 U.S.C. 102 or 35 U.S.C. 103, but so too may the inherent disclosures of a prior art reference. Inherency rejections, whether it be inherent anticipation or inherent obviousness, can be extremely difficult to overcome. Indeed, at many times it seems there is a great deal of subjectivity weaved into an inherency rejection. But that does not mean that inherency based rejections do not make sense.

As the Federal Circuit has sensibly explained, “discovery of a previously unappreciated property of a prior art composition, or of a scientific explanation for the prior art’s functioning, does not render the old composition patentably new to the discoverer.” Atlas Powder Co. v. Ireco Inc., 190 F.3d 1342, 1347 (Fed. Cir. 1999). Therefore, merely claiming of a new use, new function or unknown property that is inherently present within the prior art does will not in and of itself necessarily make the offered claim patentable. In re Best, 562 F.2d 1252, 1254 (CCPA 1977).

Inherency was initially a doctrine rooted in anticipation, but has long since been applied to become applicable to obviousness rejections as well. What this means is this: Inherency may supply a missing claim limitation in either an obviousness rejection. See Par Pharmaceutical, Inc. v. TWi Pharmaceuticals, Inc., 773 F.3d 1186 (2014). However, the Federal Circuit has always been mindful that inherency in the context of an obviousness rejection must be carefully limited. There is “a high standard in order to rely on inherency to establish the existence of a claim limitation in the prior art in an obviousness analysis…” Id.


Limitations on Inherency Rejections

In order to combat the subjective nature of inherency rejections the Federal Circuit has set forth several important limitations. For example, the fact that a certain result or characteristic may occur or be present in the prior art is not sufficient to establish the inherency of that result or characteristic. In re Rijckaert, 9 F.3d 1531, 1534, (Fed. Cir. 1993). Furthermore, “[a]n invitation to investigate is not an inherent disclosure” where a prior art reference “discloses no more than a broad genus of potential applications of its discoveries.” Metabolite Labs., Inc. v. Lab.Corp. of Am. Holdings, 370 F.3d 1354, 1367 (Fed. Cir. 2004).

Another important limitation is that the inherent teaching of a prior art reference is a question of fact, both in the context of inherent anticipation and inherent obviousness. What this means is that the patent examiner who relies upon inherence must provide some basis in fact or technical reasoning that reasonably supports the determination that the allegedly inherent characteristic necessarily flows from what has been specifically disclosed within the prior art. See Par Pharmaceutical.

This point was recently at issue in Southwire Co. v. Cerro Wire LLC (2017), where the Board in an inter partes reexamination proceeding found a reference inherently taught reducing a pulling force by at least 30% by adding a lubricant. The Board concluded that although the reference did not teach the specific limitation it would have been obvious to select an appropriate amount of lubricant to achieve the 30% limitation. The Federal Circuit disagreed, explaining: “the Board erred in relying on inherency without finding that [the reference] necessarily would achieve a 30% reduction in pulling force, but rather finding that it merely renders the limitation obvious.” Southwire Co. (emphasis in the original). In essence, it seems the Board simply thought one of skill in the art could figure it out if they tried after reading the reference, but no evidence confirming that assumption was offered.

Still further, the Federal Circuit has repeatedly warned that use of inherency in the context of obviousness must be carefully limited because “that which may be inherent is not necessarily known and that which is unknown cannot be obvious.” Honeywell Int’l Inc. v. Mexichem Amanco Holding S.A. DE C.V. (2017). As the Federal Circuit explained in Honeywell:

What is important regarding properties that may be inherent, but unknown, is whether they are unexpected. All properties of a composition are inherent in that composition, but unexpected properties may cause what may appear to be an obvious composition to be nonobvious.

It makes sense that inherent obviousness should at least in some meaningful way focus on expectations, particularly post-KSR. Since the United States Supreme Court decided KSR v. Teleflex in 2007, in order to overcome an obviousness rejection it is necessary for there to be no teaching, suggestion or motivation to combine the references, and that there was something unexpected or unpredictable in order to overcome the other six KSR rationales.


Here are some key take-away lessons for those fighting inherency rejections:

  1. “The mere fact that a certain thing may result from a given set of circumstances is not sufficient to establish inherency.” In re Rijckaert at 1534 (emphasis in original).
  2. Facts are required to establish that the reference being cited necessarily presents the claim limitation in question. See Par Pharmaceutical.
  3. An assumption, without evidence, that the reference presents the claim limitation is insufficient. See Southwire Co.
  4. That which is unknown cannot be obvious. See Honeywell.

The Author

Gene Quinn

Gene Quinn is a Patent Attorney and Editor and President & CEO ofIPWatchdog, Inc.. Gene founded in 1999. Gene is also a principal lecturer in the PLI Patent Bar Review Course and Of Counsel to the law firm of Berenato & White, LLC. Gene’s specialty is in the area of strategic patent consulting, patent application drafting and patent prosecution. He consults with attorneys facing peculiar procedural issues at the Patent Office, advises investors and executives on patent law changes and pending litigation matters, and works with start-up businesses throughout the United States and around the world, primarily dealing with software and computer related innovations. is admitted to practice law in New Hampshire, is a Registered Patent Attorney and is also admitted to practice before the United States Court of Appeals for the Federal Circuit. CLICK HERE to send Gene a message.

Warning & Disclaimer: The pages, articles and comments on do not constitute legal advice, nor do they create any attorney-client relationship. The articles published express the personal opinion and views of the author as of the time of publication and should not be attributed to the author’s employer, clients or the sponsors of Read more.

Discuss this

There are currently 2 Comments comments.

  1. Thomas Jackson October 27, 2017 4:09 pm

    Just a comment that frequently it is useful to challenge an Examiner making an inherency rejection to request the Examiner to identify how the challenged claim feature becomes inherent in view of the applied prior art – either as an anticipation or an obviousness rejection. There is inherently a gap (no pun intended) between the prior art applied and the claimed invention feaure. The Examiner can be said to apply the references in improper hindsight view of the Applicant’s invention.

  2. Night Writer October 28, 2017 9:15 am

    OT, but Gene you should read this article as it talks about the due process issues of the IPR that you have been raising. Ed the Ned posted it to anther blog.