In KSR Int’l v. Teleflex, Inc.1 the Supreme Court emphasized the predictability of an outcome as an important question to answer when deciding whether an invention would have been obvious to an artisan skilled in the area to which the invention pertains. According to the Court, inventions that are nothing more than a combination of things known and assembled in predictable ways to produce predictable results are not worthy of a patent right.

The facts before the KSR Court concerned a patented vehicle control pedal having an adjustable arm. Such technology is often predictable in the sense that one does not need to build the pedal to know how it will perform. The pedal is, therefore, known as a predictable art. Importantly, the Court found that the patent would have been obvious because the components of the claimed pedal were known and easily combined and the benefits of the combination were predictable.

By contrast, the therapeutic benefits, if any, of a novel chemical compound are not predictable. One cannot say for certain how the compound will react in a body until it has been tested. It would seem, therefore, that the obviousness inquiry under KSR ought not be easily applied to invalidate a patent on a novel compound used to treat a condition. The Federal Circuit appears to have adopted this view in its post-KSR jurisprudence.

One post-KSR strategy frequently pursued by a party attempting to invalidate a patent, in both the predictable and unpredictable arts, is the “obvious to try” test for obviousness. According to the Federal Circuit, KSR framed this test under the assumption that there was a finite and, in the context of the art, small or easily traversed number of options that would have convinced an ordinarily skilled artisan of obviousness. Accordingly, when it is inappropriate to make such an assumption, as is often the case in the unpredictable arts, the reach of KSR might appear limited. Two cases from the Federal Circuit illustrate this point.

In Abbott Labs. v. Sandoz Inc.2 the court found that a controlled release composition of erythromycin was not obvious over a controlled release composition of azithromycin because of the specific pharmacodynamic parameters chosen. When there is no predictability in the result, the court reasoned, the case differs from that faced in KSR. “The Court in KSR did not create a presumption that all experimentation in fields where there is already a background of useful knowledge is ‘obvious to try,’ without considering the nature of the science or technology.”3

In Eisai Co. Ltd. v. Dr. Reddy's Laboratories, Ltd.4 the court found that, despite a close structural similarity between the patented compound and the prior art, the gastric acid suppressing compound rabeprazole was not obvious over the anti-ulcer drug lansoprazole. Once again, the court refused to invalidate the patent on the grounds that it would have been “obvious to try.” In support of this holding, the court was quick to point out that the analysis in KSR assumed, among other things, that the prior art supplied some reason to narrow the field down to a finite number of identified, predictable solutions. The court pressed this point further. “To the extent an art is unpredictable, as chemical arts often are, KSR's focus on those 'identified, predictable solutions' may present a difficult hurdle because potential solutions are less likely to be genuinely predictable.”5

These and other cases6 suggest a trend towards treating cases that fall within the realm of the unpredictable arts differently from those of the predictable arts. The more recently decided In re Marek Z. Kubin,7 however, reminds us that a classification of the art as predictable or unpredictable is not a litmus test for obviousness under KSR. As this court aptly put it, it is inappropriate “in the face of KSR” to cling to customized “legal tests for specific scientific fields,” which are susceptible to use “in ways that deem entire classes of prior art teachings irrelevant, or discount the significant abilities of artisans of ordinary skill in an advanced area of art.” 8

From the surveyed cases, the unpredictability of an outcome or the path that would have led to the patented discovery has been demonstrated in the following ways:

  • a compound useful for purpose A led, unexpectedly, to the discovery of a compound useful for purpose B, e.g., a different therapeutic purpose;
  • a compound worked through a different mechanism, despite its structural similarity to a known compound;
  • conventional wisdom was not followed when the discovery was made, a compound was chosen, etc.  

KSR ’s impact on the availability of a patent for discoveries in fields like chemistry or biotechnology is correctly understood as less profound than discoveries in the so-called predictable arts. Yet, it should be remembered that while it is more likely that a discovery in chemistry or biology could not have been predicted, recognition of this fact alone has not led, and likely will not lead, to any presumption concerning predictability under KSR.