The U.S. Patent and Trademark Office (USPTO) has now published its 2010 KSR Guidelines Update (Update). 75 Fed. Reg. 53,643 (Sept. 1, 2010). In view of Federal Circuit case law developments since the Supreme Court decision in KSR, the USPTO published the Update to supplement the Examination Guidelines for Determining Obviousness Under 35 U.S.C. 103 in View of the Supreme Court Decision in KSR International Co. V. Teleflex Inc., originally published in 2007. Under the 2007 Examination Guidelines, six rationales were identified for finding claims obvious under 35 U.S.C. § 103, in addition to the teaching-suggestion-motivation (TSM) test. The Update includes a discussion of specific Federal Circuit decisions to clarify when obviousness rejections are proper under the rationales of combining prior art elements according to known methods to yield predictable results, substitution of one known element for another to obtain predictable results and “obvious to try”—choosing from a finite number of identified, predictable solutions, with a reasonable expectation of success. Additionally, the update provides guidance on the consideration of evidence of non-obviousness.

The Update reinforces that each application is to be decided on its own facts and that there is no generic, one size fits all, obviousness rejection. Indeed, the Update acknowledges that in view of KSR, “teaching away from the claimed invention by the prior art, lack of a reasonable expectation of success, and unexpected results … may have taken on added importance.” Regarding the use of common sense to support a conclusion of obviousness, the USPTO cannot resort to “common sense” merely to support an otherwise unsupported finding. Rather, the “common sense” must be explained with “sufficient reasoning.”

In situations where prior art elements are combined according to known methods to yield predictable results but the combined invention involves additional complexity, the Update instructs that the combination may be unobvious unless the examiner can articulate reasoning for including the added feature or steps. In addition, even if a combination is within the skill level of the ordinary artisan, the invention may be unobvious if the problem that suggested the combination was previously unknown.

With regard to substituting one known prior art element for another known prior art element, the Update explains that when determining whether a reference in a different field of endeavor may be used to support a case of obviousness, it is necessary to consider the problem to be solved. Further, while a teaching away is evidence of non-obviousness, if the reference does not teach that the combination is undesirable then it cannot be said to teach away.

Where there are various possible substitutions, the USPTO must have a reasonable expectation of success for trying the claimed substitute. Asserting “obvious to try” alone is not sufficient to maintain an obviousness rejection. In the following situations, merely asserting “obvious to try” is not sufficient: varying all parameters or trying each of numerous possible choices until one possibly arrives at a successful result and exploring a new technology or general approach that seemed to be a promising field of experimentation, where the prior art only gave general guidance as to the particular field of the invention. In addition, when asserting an “obvious to try” rationale, there must be a finite number of predictable solutions, where finite means “small or easily traversed” in the context of the art in question.

The Update also reminded examiners that all rebuttal evidence that is timely presented is to be considered when determining obviousness.

Practice Note: Some patent examiners have erroneously interpreted KSR as supporting obviousness rejections whenever the invention is a combination or substitution of known elements, notwithstanding evidence of non-obviousness. The Update, however, provides examples in which combinations of known prior art elements were held to be unobvious. A review of the factual situations leading to the holdings of nonobviousness would be very useful for rebutting rejections based on a KSR analysis.