Chapter §9.07 Combining Prior Art Disclosures

• Jurisdiction: United States

§9.07 Combining Prior Art Disclosures

Frequently, a §103 based rejection of pending application claims in the USPTO (or a §103 challenge to the validity of an issued patent in court) will be founded on the argument that the respective disclosures of two or more prior art references, in combination, would have rendered the claimed invention obvious. This argument contends that the PHOSITA, deemed to have had access to such references at the time the claimed invention was made, would have been motivated to combine their teachings, and would have reasonably expected that these combined teachings would have rendered the claimed invention obvious.

If a party seeks to invalidate an issued patent (which carries with it a presumption of validity, including a presumption of nonobviousness), Federal Circuit law mandates that a two-part standard be satisfied to establish that the claimed invention would have been obvious. The party must demonstrate " 'by clear and convincing evidence [1] that a skilled artisan would have been motivated to combine the teachings of the prior art references to achieve the claimed invention, and [2] that the skilled artisan would have had a reasonable expectation of success from doing so.' "⁴³² These two prongs are discussed below as the "motivation to combine" and "reasonable expectation" elements of proving obviousness.

[A] Teaching, Suggestion, or Motivation to Combine

Before the Supreme Court's watershed 2007 decision in KSR Int'l Co. v. Teleflex, Inc.,⁴³³ Federal Circuit precedent required that in order for a "combination of references" type of obviousness argument to succeed, there had to exist some teaching, suggestion, or motivation (hereafter TSM) that would have suggested making the claimed combination.⁴³⁴ It was legal error for a USPTO examiner or a judge or jury to merely combine the discrete disclosures of different references without evidence of some reason for the PHOSITA to have done so. Rigorous attention to the requirement for a TSM guarded against the improper use of hindsight in a nonobviousness analysis,⁴³⁵ that is, using the claimed invention as a blueprint or plan and merely lumping together multiple prior art references that each disclose some limitation of the claims.⁴³⁶ Such hindsight reasoning "discount[s] the value of combining various existing features or principles in a new way to achieve a new result—often the very definition of invention."⁴³⁷

For example, suppose that a patent claim recited "a widget comprising a lever arm A, a pulley B, and a spring C." Suppose further that the USPTO examiner rejected the claim as obvious under §103, based on the combined teachings of prior art Reference 1, which disclosed a widget having a lever arm A; Reference 2, which disclosed another sort of device (e.g., a gizmo) having a pulley B; and Reference 3, which disclosed yet another type of device (e.g., a whatzit) having a spring C. By extracting the relevant components from each of the three references and combining them, the examiner effectively recreated the patented invention by using the claim as a blueprint. Federal Circuit jurisprudence provided that if the references themselves or other prior art did not suggest the viability of making the combination, the examiner's conclusion of obviousness was legally erroneous.

The Federal Circuit's precedent required that the record contain adequate evidence of a suggestion, teaching, or motivation to combine the disclosures of the references. In the above hypothetical, an adequate suggestion to combine might have existed if, for example, prior art Reference 1 suggested that a widget could advantageously have multiple parts in addition to a lever arm, and References 2 and 3 showed benefits or advantages to including pulleys and springs in mechanical devices generally.

Earlier case law suggested that the TSM generally should be found in prior art references,⁴³⁸ but the law is no longer that restrictive, particularly following the Supreme Court's 2007 decision in KSR.⁴³⁹ Even before the Court issued KSR, the Federal Circuit recognized that motivation to combine the teachings of multiple references might be derived from the nature of the problem solved by the invention. For example, the patent in suit in Ruiz v. A.B. Chance Co.,⁴⁴⁰ was directed to a method of underpinning the foundation of a building by use of a screw anchor in conjunction with a metal bracket. One prior art reference disclosed the screw anchor component of the claims while another disclosed the metal bracket component. The Federal Circuit upheld the district court's finding of an implied motivation to combine the teachings of the two references in the nature of the problem itself: how to underpin the unstable foundation of an existing building.

Particularly with simpler mechanical technologies, the Federal Circuit observed in Ruiz, motivation may be found in the nature of the problem to be solved; the prior art references themselves need not provide an express, written motivation to combine. The district court had properly found the motivation to combine from the fact that the two pertinent prior art references "address[ed] precisely the same problem of underpinning existing structural foundations."⁴⁴¹ Sitting as the finder of fact, the district court correctly "weighed the evidence and found that, because the prior art references address the narrow problem of underpinning existing building foundations, a person seeking to solve that exact same problem would consult the references and apply their teachings together."⁴⁴²

Other Federal Circuit cases explained that evidence of a TSM to combine references could come not only from the nature of the problem to be solved or the teachings of the prior art applied against the claims at issue, but also from the prior art in general as well as from the "common knowledge" of a PHOSITA. After the Supreme Court granted certiorari in KSR, the Federal Circuit denied that its TSM test was a "rigid, categorical rule" and explained that "[t]he motivation need not be found in the references sought to be combined, but may be found in any number of sources, including common knowledge, the prior art as a whole, or the nature of the problem itself."⁴⁴³

The motivation to combine argument is a factual inquiry that can be conceptualized as a subset of Graham factor (1), scope and content of the prior art,⁴⁴⁴ but other factors may also impact the analysis. As the Federal Circuit has observed:

accurate assessment of whether to combine references may require attention to other Graham factors. For example, the level of skill in the art [ Graham factor (3)] may inform whether the artisan would find a suggestion to combine in the teachings of an exemplar of prior art. Where the level of skill is high, one may assume a keener appreciation of nuances taught by the prior art. Similarly, appreciation of the differences between the claims in suit and the scope of prior art references [ Graham factor [2)]—a matter itself informed by the operative level of skill in the art—informs the question of whether to combine prior art references. At bottom, in each case the factual inquiry whether to combine references must be thorough and searching. ⁴⁴⁵

[B] Reasonable Expectation of Success

The existence of a TSM (or, as more broadly expressed post-KSR, some reason for combining features of multiple prior art references⁴⁴⁶) is only part of what a validity challenger must show to establish obviousness. Federal Circuit decisions also require the challenger to show that the PHOSITA would have attempted the combination with a "reasonable expectation of success."⁴⁴⁷ More specifically, in a case in which all claim limitations are found in multiple prior art references, the validity challenger must establish by clear and convincing evidence that (1) a skilled artisan would have been motivated to combine the teachings of the references in order to achieve the claimed invention and (2) the skilled artisan would have had a reasonable expectation of success in so doing.⁴⁴⁸

[1] Degree of "Reasonableness"

The "expectation of success" prong requires only a reasonable certainty that the combination will succeed, however, not an absolute conviction. For example, in Pfizer, Inc. v. Apotex, Inc.,⁴⁴⁹ the claimed invention was directed to Pfizer's NORVASC drug product, useful in the treatment of hypertension and angina. The active ingredient in NORVASC is the chemical compound amlodipine, for which Pfizer had previously obtained a separate patent. That earlier patent, claiming amlodipine per se, served as the primary prior art reference in the Pfizer v. Apotex litigation. Pfizer's earlier patent disclosed amlodipine maleate as the preferred salt form of amlodipine, and listed other pharmaceutically acceptable acid addition salts.⁴⁵⁰ What Pfizer claimed in the later patent it asserted against Apotex, however, was amlodipine besylate, a different salt form of amlodipine that had not been explicitly disclosed in Pfizer's earlier patent.⁴⁵¹

The Federal Circuit reversed a district court's judgment that had sustained Pfizer's amlodipine besylate patent against Apotex's obviousness challenge. In addressing the reasonable expectation of success prong, the appellate court emphasized that "only a 'reasonable,' not an absolute, expectation of success is required to support obviousness."⁴⁵² In other words, some unpredictability does not negate a reasonable expectation of success; the expectation of success need not be guaranteed.⁴⁵³ The Federal Circuit defined a reasonable expectation of success in Pfizer as "evidence [that] would convince a reasonable finder of fact that the skilled artisan would have had a reasonable expectation of success that an acid addition salt of besylate would form and would work for its intended purpose."⁴⁵⁴ Although the Federal Circuit could not quarrel with the district court's finding that "in 1986, it was generally unpredictable as to whether a particular...