The Federal Circuit affirmed a Patent Trial and Appeal Board (PTAB) decision affirming an examiner’s rejection of claims directed to oral inhalation of the drug zanamivir to treat influenza. The examiner rejected the applicant’s claims on the basis that they were obvious over two prior art references. The first reference taught treating influenza by the nasal inhalation of zanamivir, and the second reference taught treating influenza by the inhalation of a compound similar to zanamivir. The second reference did not explicitly teach oral inhalation, but the court found that teaching “inhalation” generally includes both oral inhalation and nasal inhalation. The court found that treating influenza by oral inhalation would be obvious because influenza affects the lungs, and oral inhalation delivers more drugs to the lungs than nasal inhalation. The applicant further argued that one of skill in the art would not use an oral inhalation method of zanamivir to treat influenza because oral inhalation delivers more drugs to the lower respiratory tract, and it was thought at the time of the invention that it was more effective to deliver anti-influenza drugs to the upper respiratory tract. The court rejected this argument because some strains of influenza also attack the lower respiratory tract and young children are more susceptible to lower respiratory tract infections.
The court considered and rejected the applicant’s expert’s arguments that oral inhalation of zanamivir provided unexpected results. PTAB and the court found that a study presented by the expert did not show unexpectedly superior results and that another study was not persuasive because it dealt with the prevention of influenza, not the treatment of it.
In dissent, Judge Newman argued that the court failed to properly consider the applicant’s expert’s opinion. Specifically, the expert concluded from a large international study that the effectiveness of orally inhaled zanamivir as compared with nasal administration could be considered an unexpected result. Judge Newman also criticized the court’s finding because for a method to be obvious to try in unpredictable arts, such as medicinal treatment, there must be some suggestion in the prior art that the method would have a reasonable likelihood of success. Judge Newman noted that the prior art did not suggest oral inhalation was a method for administration of zanamivir. In addition, Judge Newman found that the court’s statement that inhalation is reasonably understood to include oral inhalation is without authority.
In re: Constantin Efthymiopoulos, Case No. 2016-1003 (Fed. Cir. Oct. 18, 2016).