Federal Circuit Uses Patent Application’s Own Words to Find Method of Treating Cancer Obvious to Try

Before KSR, ¹ it was thought that obviousness under 35 USC § 103 could not be demonstrated by showing that a particular combination was obvious to try. The Supreme Court clarified that “when there is a . . . problem and there are a finite number of identified, predictable solutions,” and if pursuing the known options leads to the anticipated success, “it is likely the product not of innovation but of ordinary skill and common sense. In that instance, the fact that a combination was obvious to try might show that it was obvious under § 103.”² Using the “obvious-to-try” rationale, in a recent opinion the Federal Circuit cited the patent application’s own disclosure to uphold the USPTO’s rejection of a method of treating cancer. ³

The USPTO rejected as obvious claims directed to a method of treating cancer in vivo in a mammal by administering NK-92 cells. Both the district court and the Federal Circuit upheld the rejection. The Federal Circuit found that it was undisputed that NK cells and T cells were the only two types of immune cells known to have efficacy.⁴ In particular, the art recognized that TALL-104 cells and NK-92 cells (the cells recited in the claims) attacked cancer cells via the same mechanism.⁵ The Federal Circuit concluded that combining the teachings of the prior art would have at least been obvious to try given the limited number of possibilities in the prior art and the many explicit suggestions “toward a particular solution,”.⁶

In addition to citing the teachings of the prior art, at least three times the Federal Circuit used the Appellant’s own patent application as evidence that the claimed method would have been obvious. For instance, the Federal Circuit cited the application as acknowledging that prior TALL-104 studies demonstrated antitumor activity in vivo.⁷ Further, the Federal Circuit cited the patent application as disclosing that the prior art described the superior qualities of the NK-92 cell line.⁸ Lastly, the “patent application itself recognized that prior investigators turned to allogenic therapy in preference to using a patient’s own cells.” ⁹ In each case, the patent application’s own disclosure was used by the Federal Circuit to undermine the Appellant’s arguments during the appeal.

The court’s opinion shows the disadvantages of including information regarding the background of the invention or the reasoning that led to the invention. Although patent application drafters may wish to mention the prior art in order to “tell a story,” prosecutors must be aware that this story may be used to show that the invention, at the very least, would have been obvious to try.