In two companion opinions, the U.S. Court of Appeals for the Federal Circuit largely affirmed rulings of the Board of Patent Appeals and Interferences (the Board) against a patent owner relating to written description. However, the Court reversed the Board’s finding that the patent owner failed to make a prima facie showing of prior actual reduction to practice of one interference count. Yorkey v. Diab, Case Nos. 08-1577, -1578 (Fed. Cir., Apr. 7, 2010) (Michel, C. J.).

The technology-in-suit is for measuring oxygen in patients’ blood by a method called “pulse oximetry.” The oxygen content of the blood is a critical clinical measurement because failure of the heart and lungs to provide high enough levels of oxygen in the blood leads to brain death within minutes. Blood oxygen level is hard to measure accurately by noninvasive techniques in a living patient because the blood is in motion as it circulates and because of other factors, causing “motion noise.” The interference proceedings involved method claims using mathematical processing to filter out motion noise.

Yorkey had a patent for measuring blood oxygen in the presence of motion noise. The Yorkey patent claimed priority to a June 1995 application. Diab and co-inventors filed the two patent applications (the ’542 and ’604 patent applications) claiming priority to an October 1994 application. There were three counts in the interferences. Case No. 08-1577 involved the ’542 patent application and two counts that covered two of Yorkey’s patent claims; Case No. 08-1578 involved the ’604 application and the third count that covered one claim of Yorkey’s patent claims. In the course of the interference proceedings, Yorkey filed unsuccessful preliminary motions asking the Board to invalidate the Diab applications for inadequate written description on all three counts. The Board awarded priority to Diab. Yorkey appealed.

The Federal Circuit affirmed the denials of Yorkey’s motions. In the 08-1578 appeal, the Federal Circuit affirmed as reasonable the Board’s claim construction under the “broadest reasonable interpretation” standard. Yorkey argued that the ’604 application described solving two functions, not three, as claimed in the patent. The Federal Circuit, citing to the expert testimony, rejected Yorkey’s argument. The Court concluded that the record contained substantial evidence that the Diab specification described the use and solution of all three functions and that the specification would have reasonably conveyed to an artisan of ordinary skill that Diab was in possession of the claimed subject matter in 1994. In the 08-1577 appeal, the Federal Circuit rejected Yorkey’s written description argument that “substantially uncorrelated” was not the same thing as “[completely] uncorrelated” because, as the Court explained, correlation is a mathematical term of art that inherently turns on statistical significance, not absolutes. The Federal Circuit also rejected Yorkey’s argument that Diab’s disclosure of matrix methodology was insufficient to show possession of the invention and noted that Yorkey’s expert never explained what, if any, additional methodology disclosure was missing.

However, Yorkey won 08-1578 appeal on prior actual reduction to practice relative to one count. The Federal Circuit found clear error in the Board’s findings regarding data collected using a 1993 computer program. The Court stated that the declarations of Yorkey and his research associate, along with other evidence, were sufficient to meet Yorkey’s burden to make a prima facie showing that all limitations of the count were met by the actual reduction to practice. The Court thus rejected the Board’s conclusion that the proffered evidence was “uncertain and speculative.”