What Constitutes Non-Analogous Art?

Obviousness under US Patent Law

An invention must be non-obvious when compared to related prior art. Specifically, under 35 U.S.C. § 103, an invention cannot be patented if the differences between the claimed invention and the prior art are such that the invention as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains.

The evaluation of obviousness involves a multi-step analysis, typically beginning with the identification of the scope and content of prior art related to the claimed invention. The next steps involve ascertaining the differences between the prior art and the invention at issue and assessing the level of ordinary skill in the pertinent art.

The seminal case of Graham v. John Deere Co. of Kansas City established the framework for assessing obviousness, which includes examining these objective indicators. Later cases, such as KSR International Co. v. Teleflex Inc., have evolved the standards, emphasizing a flexible, expansive approach to determining obviousness, which includes an understanding that obviousness can be based on common sense and the ordinary creativity of those skilled in the art. This move away from a rigid, formulaic approach allows for more nuanced considerations of what constitutes an obvious improvement in a field, ensuring that patents only cover truly innovative advancements.

A proper obviousness rejection under must meet several key requirements. First, there must be a clear identification of the relevant prior art that would have been known to a person having ordinary skill in the art (POSITA) at the time the invention was made. The rejection should explicitly state which specific prior art references are being combined and how they relate to each element of the claimed invention. Additionally, the rejection must include a rationale for combining these references, supported by a reasoned explanation that includes factual findings. This rationale should demonstrate that the combination of prior art references would have been obvious to a POSITA, not merely speculative or general. The rejection also needs to address any teaching away by the prior art, which could argue against the combination. Finally, any assertions of obviousness must consider the claimed invention as a whole and not just individual elements in isolation.

What is Prior Art?

Prior art refers to all information that has been made available to the public in any form before the effective filing date of a patent application. Under the US Patent Act, the patentability of an invention depends on how distinctive it is from the closest related prior art. Examples of prior art include previously issued utility patents, design patents, published patent applications, and other public disclosures such as articles, books, or products on the market, which predate the filing of the patent application under examination. The effective filing date of a patent application is the reference point to determine whether particular information qualifies as prior art.

Patent examiners perform a prior art search to find prior art related to the invention claimed in the patent application. When a patent examiner finds prior art that predates the effective filing date and discloses similar innovations, the examiner may cite the prior art found to reject the claimed invention as anticipated or obvious. This process ensures that patents are granted only for genuinely new and inventive contributions to the field.

What is an Analogous Prior Art Reference

A proper obviousness rejection must based on prior art that is "analogous" to the claimed invention. See M.P.E.P. § 2141.01(a). A reference qualifies as “analogous” if it meets one of two separate tests. There is the "field of endeavor" test, which requires that the prior art reference is from the same field of endeavor. The other test requires that the prior art reference is "reasonably pertinent" to a particular problem addressed by the claimed invention. In re Klein, 647 F.3d 1343, 1348 (Fed. Cir. 2011) (quoting In re Bigio, 381 F.3d 1320, 1324 (Fed. Cir. 2004)). These tests are exclusive to one another. If the prior art meets the field of endeavor test, it need not address the problem addressed in the patent application. If the prior art meets the reasonably pertinent test, it need not be in the same field of endeavor.

In an exemplary case, the Patent Trial and Appeal Board issued a decision in Ex parte Taskinen reversing obviousness rejections because the examiner did not properly establish that a cited secondary prior art reference was analogous to the claimed invention. The patent application disclosed adjustable massage apparatuses. The examiner rejected the claims as being obvious in view of Taskinen (US 2008/0200778), Khen (WO 2008/063478), and Lockwood (US 2003/0014022). Lockwood discloses wound treatment apparatuses.

The examiner asserted that Lockwood is the in the same field of endeavor as the invention, but failed to explain how Lockwood's disclosure was analogous to massage apparatuses. The examiner offered no assertion or explanation as to whether Lockwood was “reasonably pertinent” to the invention described in the patent application. The applicant challenged the examiner's assertion that Lockwood was in the same field of endeavor, arguing that a POSITA would not look to Lockwood because the structure and purpose the devices disclosed by Lockwood are unrelated to massage devices. Applicant argued that while Lockwood describes a low pressure suction device, the structure and purpose of the Lockwood device are different than a massage apparatus. Ergo, a POSITA would look to Lockwood in conceiving the device disclosed by the primary reference, Taskinen. Applicant further argued that a POSITA would not combine features of Lockwood with Taskinen because they were not practicably combinable with the device of Taskinen.

The Board found that Lockwood was not in the same “field of endeavor” as the claimed invention, because massage devices are not remotely vacuum treatment devices. The Board explained that the field of endeavor test requires the examiner to determine the appropriate field of endeavor by reference to explanations of the invention’s subject matter in the patent application, including the embodiments, function, and structure of the claimed invention. In re Bigio, 381 F.3d at 1325. The test is not satisfied by a subjective determination by the patent examiner. Id. at 1326. The patent office must have a basis in the application and its claimed invention for defining the scope of the field of endeavor. Id.

The Board found that the patent examiner's opinion that Lockwood was in the same field of endeavor did not find a basis objective evidence, and amounted to an unsupported legal conclusion. The field of endeavor identified by the examiner (vacuum treatment devices for a user) was too generic. The PTAB found that Appellant’s field of endeavor was actually massage devices, as demonstrated by the technical field, the discussion of the prior art, the detailed description of the invention, the figures, and the patent claims provided in the patent application. This case illustrates that the patent applicant must carefully review the prior art relied upon by the patent office and challenge obviousness rejections based on non-analogous art.

Is the Prior Art Reasonably Pertinent?

A prior art reference meets the "analogous art requirement" and can be relied upon in an obviousness rejection under 35 U.S.C. § 103 if it is reasonably pertinent to the particular problem with which the inventor is involved. The reasonably pertinent test is independent of whether a prior art reference is from the same field of endeavor.

The test for whether a prior art reference is "reasonably pertinent" does not require the prior art to be in the exact field of the claimed invention; rather, a reference is reasonably pertinent if the prior art at least one of the issues addressed by the claimed invention and has the same purpose with respect to that issue.

In the case of Sanofi-Aventis Deutschland GmbH v. Mylan Pharmaceuticals Inc., the Federal Circuit addressed the applicability of the "reasonably pertinent" test for determining analogous art in patent law. This case highlighted critical issues regarding the classification of prior art as analogous in the context of an inter partes review (IPR) proceeding before the Patent Trial and Appeal Board.

Sanofi’s ’614 patent, which pertained to a metered drug-dosing device, was challenged by Mylan who argued that the patent was obvious in light of three prior art references: Venezia, Burren, and primarily, de Gennes. The latter, though related to automobile technology—a field distinct from drug delivery—was claimed by Mylan to be analogous because it addressed similar mechanical issues.

The crux of the dispute revolved around whether de Gennes was "reasonably pertinent" to the specific problem addressed by the ’614 patent. The Patent Trial and Appeals Board (PTAB) initially found de Gennes to be analogous art, reasoning that it dealt with relevant mechanical issues despite its primary application in a different field. However, this conclusion was based on an indirect comparison where de Gennes was aligned with Burren rather than directly with the ’614 patent.

On appeal, Sanofi argued that PTAB improperly expanded the scope of analogous art by shifting the burden from Mylan to Sanofi, requiring the patentee to prove non-obviousness. The Federal Circuit sided with Sanofi, noting that patent challengers must clearly establish the pertinence of prior art directly to the challenged patent. The Court emphasized that the determination of whether a reference is "reasonably pertinent" relies on its direct relevance to the problem addressed by the patent in question, not merely its presence in related discussions or its utility in solving similar issues in a different context.

The Federal Circuit's decision underscores the necessity for patent challengers to meticulously demonstrate the relevance of prior art to the specific patent challenges, particularly through the lens of the "reasonably pertinent" standard. It serves as a reminder that the burden of proof in establishing obviousness lies with the challenger, who must convincingly show that the prior art directly pertains to the patented invention.

Dealing with Flawed Prior Art Rejections in a Patent Application

The foregoing cases illustrate that both patentees and challengers to thoroughly evaluate and argue the analogous nature of prior art from the earliest stages of patent disputes. Legal frameworks require that the art must either be within the same field of endeavor or reasonably pertinent to the particular problem addressed by the invention. Court decisions like Sanofi-Aventis have underscored the necessity of that the prior art must be sufficiently related to to the invention for it to be a proper basis for rejecting a patent claim as non obvious. The patent office must meet the legal requirements and its own examination guidelines in determining whether an invention is obvious.