Addressing the burden of proof for swearing behind the priority date of an invalidating reference, the US Court of Appeals for the Federal Circuit reasserted that unsupported evidence of the alleged inventor regarding the time of conception for priority purposes is not sufficient proof of prior conception. Apator Miitors ApS v. Kamstrup A/S, Case No. 17-1681 (Fed. Cir., Apr. 17, 2018) (Moore, J).

Kamstrup filed a petition for inter partes review (IPR) of Apator’s patent, and the Patent Trial and Appeal Board (PTAB) instituted review of particular claims based in part on a published US patent application to Nielsen. The effective filing date of the Nielsen reference was 18 days before the filing date of the application that matured into Apator’s patent.

During the IPR proceeding, Apator attempted to swear behind the Nielsen reference. The PTAB rejected this attempt, finding that Apator’s only evidence of an earlier conception date consisted of statements by the inventor. In reaching its conclusion, the PTAB stated that “mere unsupported evidence of the alleged inventor, on an issue of priority, as to . . . conception and the time thereof, cannot be received as sufficient proof of . . . prior conception.” Having found that Apator was not entitled to an earlier conception date, the PTAB went on to find that the claims at issue were not patentable in view of the Nielsen reference. Apator appealed.

The Federal Circuit affirmed, finding that substantial evidence supported the PTAB’s finding that Apator failed to sufficiently corroborate the inventor’s testimony of conception prior to the effective filing date of the Nielsen reference. The Court stated that it was Apator’s burden to prove that the inventor conceived of the invention prior to the Nielsen reference’s effective filing date. After reviewing email evidence and the inventor’s testimony, the Court determined that Apator had failed to carry its burden because it did not proffer any evidence of the inventor’s conception that was not supported solely by the inventor himself. The Court found that the email evidence was not sufficient because “there are no indicia in either the body or header of the email indicating a file is attached, let alone a file [related to the invention].” The Court also found that the email evidence could only be interpreted with the assistance of the inventor’s testimony, and the supposedly attached file did not contain adequate evidence of its creation date.

Practice Note: For pre-America Invents Act patent applications, it remains helpful to retain evidence of conception, such as witnessed lab notebooks, electronic files, and emails and attachments in full context.