On Friday, June 1st, the Court of Appeals for the Federal Circuit issued a decision in In re: Durance striking down a decision by the Patent Trial and Appeal Board (PTAB) that affirmed a patent examiner’s obviousness rejection of a microwave vacuum-drying apparatus and associated method. The Federal Circuit panel consisting of Judges Alan Lourie, Jimmie Reyna and Raymond Chen determined that the PTAB erred in not considering arguments offered in the patent applicant’s reply brief, which were properly made in response to the examiner’s answer.

The patent application at the center of this case is U.S. Patent Application No. 20100213895, titled Apparatus and Method for Microwave Vacuum-Drying of Organic Materials. Filed in October 2008, the applicant originally claimed an apparatus for dehydrating organic material including a vacuum chamber having an input end for introduction of a container for the organic material and a discharge end for removing the container; a microwave generator; a microwave-transparent window for transmission of microwave radiation into the vacuum chamber; means for reducing pressure inside the vacuum chamber; means for loading the container into the chamber’s input end; means for rotating the container inside the chamber; means for moving the rotating container through the vacuum chamber from the input end to the discharge end; and means for unloading the container of dehydrated organic material from the vacuum chamber at the discharge end. This method of dehydrating organic material, useful in the food processing and medicinal herb industries, overcomes limitations of convention methods using air-drying, which is slow, and freeze-drying, which is expensive.

In September 2014, the examiner issued a final rejection, which rejected all 37 claims of the patent application on 35 U.S.C. § 103 for obviousness and 35 U.S.C. § 112 for not meeting the written description requirement and lack of enablement. The obviousness finding was based on two pieces of prior art: U.S. Patent No. 6442866, titled Method and Apparatus for Drying or Heat-Treating Products (“Wefers”) and issued in September 2002; and U.S. Patent Application No. 20050019209, titled Method and Device for Sterilizing Containers (“Burger”) and filed in July 2002. The examiner rejected most of the ‘895 patent applications claims after finding that Wefers disclosed every limitation of claim 1 except for the tumbling limitation, which was itself disclosed by Burger. The examiner rejected Durance’s argument that rotating the container to enhance tumbling of the organic material was not present in the Wefers and Burger combination; the examiner found that the organic material’s tumbling was an inherent function of all rotating containers. On the indefiniteness finding, the examiner found that the patent application’s specification did not meet the written description requirement under Section 112 because it did not discuss the rotational speed necessary to tumble the organic material.

After an examiner interview in December 2014, the examiner withdrew the rejection based on the Section 112 grounds but maintained the obviousness rejection based on Burger’s teaching of a transportation means rotating a container through a vacuum chamber from the inlet to the outlet. Durance appealed to the PTAB, arguing that Burger taught the application of plasma to the surface of containers and not the rotation of the containers to tumble the contents for balancing out the microwave radiation applied to the cylinders. Durance further argued that Wefers taught away from agitating products during transportation because it stressed the “gentle continual transport” needed to reduce maintenance expenses. The examiner answered this argument based on new grounds that there was no structural difference between Durance’s claimed invention and the combination of the prior art references. Although Durance argued that the examiner’s understanding of structural identity for rejection, which had never before been articulated, was extremely inaccurate as the claimed invention in the ‘895 patent application required the use of gears, not simply gravity. The PTAB sided with the examiner, finding that Durance’s arguments only addressed individual references and not the combination.

Durance appealed for rehearing by the PTAB, arguing that the Board erroneously ignored reply brief arguments related to the structural identity rejection. In not addressing arguments that the claimed structure is different than the Burger structure, the PTAB “misapprehend[ed] the law” on inherency by ignoring the argument that structural identity cannot be used to show that a method claim is inherently performed by a combination of prior art references. In denying the request for rehearing, the PTAB stated that it did not misapprehend the doctrine on inherency because it didn’t invoke that doctrine in affirming the examiner’s rejection. “In the interest of fairness,” the Board did consider Durance’s reply brief argument that the amount of material packed into the container affects whether the material would tumble, but the Board reiterated that it would not consider other reply brief arguments.

On appeal to the Federal Circuit, Durance argued that substantial evidence doesn’t support the PTAB’s finding that the combination of the prior art references taught the tumbling limitation either expressly or inherently. Durance also argued that the PTAB lacked substantial evidentiary support to show that a skilled artisan would modify Wefers to include the rotation feature disclosed by Burger.

In its discussion of the issues in the appeal, the Federal Circuit opined that “the Court is not confident in the Patent Office’s reasoning for its rejection of the Application” based upon the shifting arguments offered in the patent examiner’s rejections, as well as the PTAB’s argument on appeal that the Federal Circuit should find inherency in the first instance after the PTAB told Durance that inherency was never invoked. In analyzing 37 C.F.R. § 41.41(b), the relevant statute under which the PTAB waived Durance’s reply brief arguments, the Federal Circuit noted that the statute allows a patent owner to include responses to an examiner’s answer in a reply brief. Nothing in the statute bars the patent owner from addressing new arguments made by the examiner that were not articulated in the Final Office Action, the appellate court found.

“[T]he equivocal nature of the examiner’s and Board’s remarks throughout the examination of the [‘895] application, including whether inherency was the basis for the rejection, clouded the issues before Durance. Accordingly, Durance had no notice, prior to the examiner’s answer, of this ground on which his application was being rejected.”

The PTAB’s refusal to consider Durance’s reply brief arguments on structural dissimilarity between the patent application and the prior art references required vacature of the agency’s decision and remanding the case back to the Board, the Federal Circuit held. On remand, the Federal Circuit is directing the PTAB to consider two arguments made by Durance: whether the divider walls in the containers claimed in Durance’s patent application are part of the claimed structure of the tumbling limitation under Section 112; and whether a structural identity rejection can be used to find a prima facie case of obviousness for the method claims.