Not So Obvious After All: PTAB Lacked Evidence to Eradicate University’s Disinfection Method

| Daniel P. HughesKarl W. Kowallis


Before Reyna, Clevenger, and Stoll. Appeal from the Patent Trial and Appeal Board.

Summary: The Federal Circuit reversed the PTAB’s obviousness decision because the inventors succeeded where the prior art failed and there could be no expectation of success based on the failed attempts of the prior art.

The University of Strathclyde patented a method for inactivating harmful bacteria using blue light without requiring a photosensitizer. The PTAB determined the claims would have been obvious over the prior art Ashkenazi reference in view of the prior art Nitzan reference. Neither, Nitzan or Ashkenazi disclosed inactivating the specific bacteria without using a photosensitizer and Nitzan disclosed experiments that failed to achieve any inactivation without a photosensitizer.  However, the PTAB found still found this limitation obvious because Askenazi taught that increasing light doses would result in greater inactivation of bacteria.

On appeal, the Federal Circuit reversed. The Federal Circuit found no justification for combining Ashkenazi’s experiments, which used a photosensitizer, with Nitzan’s failed experiment without a photosensitizer, to arrive at an embodiment in which bacteria is killed by exposing it to blue light without using a photosensitizer. The Federal Circuit concluded that “where the prior art evidences only failures to achieve that at which the inventors succeeded, no reasonable fact finder could find an expectation of success based on the teachings of that same prior art.”

Editor: Paul Stewart