Yesterday, the Federal Circuit issued an opinion clarifying that the introduction of new evidence is not only permitted, but “is to be expected,” in inter partes review proceedings. As long as the opposing party is given notice of the evidence and an opportunity to respond to it, the introduction of new evidence is permissible under the Administrative Procedure Act (APA).

As background, the patents challenged in the IPRs on appeal relate to treating Pompe’s disease with injections of a human acid α-glucosidase. The PTAB instituted IPR on various obviousness grounds. After institution, the patent owner argued that, because of all of the combinations of references described in in vivo experiments, a person of ordinary skill in the art would not find those experiments predictive of results in a human patient. The patent owner further argued that because the PTAB did not institute review based on any references that included in vivo data, the petitioner should not be permitted to use any prior art showing successful in vivo tests to demonstrate obviousness. In reply, the petitioner cited to two in vivo studies that related to the relevant enzyme in the in vivo experiments discussed in the prior art references. In its final written decision, the PTAB referred to those in vivo references as support for its findings as to the state of the art. Thus, based on the evidence before it, the PTAB found that by a preponderance of the evidence, the challenged claims would have been obvious.

On appeal, the patent owner argued that the PTAB violated the APA’s requirements of notice and an opportunity to respond by relying in its final written decision on “facts and legal arguments” that were not set forth in the institution decisions. The Federal Circuit disagreed, finding that the PTAB did not “change theories in midstream,” much less deny the patent owner notice of any change. The PTAB’s final written decision found the claims unpatentable on the same grounds as set forth in the institution decision and no others. The Federal Circuit explained that the “development of evidence in the course of the trial is in keeping with the oppositional nature of an inter partes review proceeding.” The Federal Circuit further found that the patent owner received adequate notice of the issues that would be considered, and ultimately resolved, at the hearing. The patent owner itself raised the issue of in vivo studies in its patent owner response. The petitioner then referenced both in vivo references in its reply. And the judges questioned patent owner’s counsel about the in vivo references at the hearing. On this record, the Federal Circuit found that the patent owner had actual notice of the references and an opportunity to respond to them.

This IPR exemplifies that in some cases, a petitioner can benefit from introducing new evidence with its reply to rebut a patentee’s non-obviousness argument. Additional evidence showing the state of the art at the time of the invention may be useful for rebutting a patentee’s argument regarding the knowledge a skilled artisan would bring to bear when reading the prior art identified as producing obviousness. Patent owners should thus be selective in their patent owners’ response and be cautious of including arguments that could be undermined by additional evidence of the state of the art. Additionally, if a petitioner does rely on additional evidence in its reply, a patent owner should consider whether it has grounds to file a motion to exclude the evidence and, if not, consider whether it should seek leave to file a surreply to respond to the new evidence.