24Feb 2022

In a recent case, the Federal Circuit reversed the USPTO Patent Trial and Appeal Board (PTAB) decision finding certain method claims obvious, because the evidence did not support the PTAB’s finding that a person of ordinary skill in the art would have had a reasonable expectation of success. Notably, the court instead found the prior art to report failure.

 The patent at issue was directed to methods for inactivating Gram-positive bacteria.

 Claim 1 of the ‘706 patent recites, in relevant part:

 1. A method for disinfecting … by inactivating one or more pathogenic Gram-positive bacteria …. said method comprising exposing … visible light without using a photosensitizer

 The highlighted phrase was the feature at issue.

The IPR Decision

The PTAB found the claims obvious over two prior art references: the first reported an experiment to photoinactivating Gram-positive bacteria using photosensitizers, and the second reported an experiment showing photoinactivation of specific Gram-positive bacteria only when photosensitizers were used.

The PTAB found “a reasonable expectation of successfully” combining the references to arrive at an effective method for inactivating Gram-positive bacteria.

The Federal Circuit Decision

The Federal Circuit decision focused on the arguments presented by the patentee that the PTAB erred in finding that combination of the cited references teach photoinactivation without the use of photosensitizers, and erred in finding a reasonable expectation of success.

The Federal Circuit agreed. First, it held that the first reference only described photoinactivation with photosensitizers and that second reference showed success only with photosensitizers and a failure to photoinactivate without photosensitizers. Thus, the two references, alone or in combination, failed to describe the claimed limitations.

On the second argument, the Federal Circuit argued that there was a complete lack of evidence in the record that any bacteria were inactivated after exposure without using a photosensitizer. Thus, such failure goes against a finding of a reasonable expectation of success.

In other words, the Federal Circuit found that the prophetic possibility mentioned in the prior art could not be considered substantial evidence to support a reasonable expectation of success.

In this case, the reasonable expectation of success was negated by the prior art evidences failures to achieve that at which the inventors succeeded.

Please contact me at silvia@salvadorilaw.com with questions or comments.

Silvia Salvadori, PhD

Silvia Salvadori, PhD