An Eye Toward Prosecution History

EYE THERAPIES, LLC v. SLAYBACK PHARMA LLC

Before Taranto, Stoll and Scarsi (sitting by designation)

Summary:  The patent’s prosecution history required a restrictive interpretation of the term “consisting essentially of.”

On petition by Slayback Pharma, LLC, the Patent Trial and Appeals Board considered the meaning of the transitional phrase “consisting essentially of” in Eye Therapies, LLC’s patent.  The patent claimed a method for reducing eye redness “consisting essentially of administering brimonidine to a patient.”  In its opinion, the Board rejected Eye Therapies’ arguments that the claims were limited to a method for administering brimonidine as the sole active agent and concluded that additional active agents that reduce eye redness may be present.  Applying this construction, the Board found the challenged claims unpatentable for obviousness.  Eye Therapies appealed.

The Federal Circuit concluded that the Board erred in its construction of the phrase “consisting essentially of” by not correctly interpreting the prosecution history.  Specifically, the Federal Circuit found that, during prosecution, the applicant replaced “comprising” with “consisting essentially of” to overcome a rejection.  Because the applicant equated the “consisting essentially of” language to “methods which do not include administering other active agents,” and because the examiner issued the patent based on that change alone, the Federal Circuit reasoned the “consisting essentially of” limitation should be interpreted more restrictively than usual to disallow any additional active agents.  The Federal Circuit remanded for further consideration under the correct claim construction.

Editor: Sean Murray