IP Law Daily Oral flu treatment method patent claims invalid as obvious
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Tuesday, October 18, 2016

Oral flu treatment method patent claims invalid as obvious

By Jody Coultas, J.D.

A patent application for a method of treating or preventing influenza by oral inhalation was properly rejected as the claims were invalid as obvious in light of prior art, according to the U.S. Court of Appeals for the Federal Circuit (In re Constantin Efthymiopoulos, October 18, 2016, Prost, .).

U.S. Patent Application No. 08/737,141 (the ’141 application) relates to methods of treating or preventing influenza by administering the drug zanamivir by oral inhalation.

An Examining Attorney rejected all pending claims as obvious over Australian Patent No. AU-A1-27242/92 ("Von Itzstein II"), in view of WIPO Publication WO 91/16320 ("Von Itzstein I") and a number of other references. The Patent Trial and Appeal Board affirmed all of those rejections. The patent applicant requested rehearing, which was denied.

On appeal, the patent applicant argued that none of the prior art references, alone or in combination, teach administration of zanamivir by inhalation through the mouth, and that a person of ordinary skill would not have expected that the administration of zanamivir through inhalation by mouth only would be effective.

The Board did not err in holding that the patent claims were invalid as obvious, according to the court. There was no dispute that Von Itzstein I disclosed the use of zanamivir to treat and prevent influenza, or that Von Itzstein II disclosed several pages of different administration methods for an adjacent homologue of zanamivir to achieve the same result—treating or preventing influenza. Also, Von Itzstein II’s disclosed administration through "inhalation" by oral inhalation. In view of the other prior art references that taught the well-known availability of inhalers, that oral inhalation delivers more drug to the lungs than nasal inhalation, and the fact that influenza infects the lungs, the examiner and Board properly concluded that treating influenza by oral inhalation of zanamivir would have been obvious.

Similarly, the patent applicant was unable to show that a skilled artisan would not reasonably expect zanamivir to be effective if administered through oral inhalation, according to the court. It was known that certain strains of the influenza virus attack the lower respiratory tract and that young children in particular were more susceptible to lower respiratory tract infections from the virus. Oral inhalation delivers more drugs to the lungs as compared to nasal inhalation. Thus, there was substantial evidence that a skilled artisan would have a reasonable expectation of success in combining the Von Itzstein references.

The Board also properly concluded that the claimed method would not necessarily yield an unexpectedly superior result, according to the court.

Dissent. Judge Newman dissented from the majority’s opinion, noting that treatment by oral inhalation would not have a reasonable expectation of success based on the understanding of those skilled in the art at the time of the invention. For a method to be obvious to try, there must be some suggestion in the prior art that the method would have a reasonable likelihood of success. It was undisputed that, at the time of this invention, it was believed that the influenza virus infected primarily the upper respiratory tract, and undisputed that there was not a reasonable expectation that administration to the lower respiratory tract by oral inhalation would be effective. The prior art did not show or suggest oral inhalation, either for zanamivir or for any related compounds. Judge Newman argued that the statement that inhalation was "reasonably understood" to include oral inhalation, was without authority. Therefore, he would not have found the patent claims obvious.

The case is No. 2016-1003.

Attorneys: Lynne A. Borchers (Myers Bigel Sibley & Sajovec, PA) for Constantin Efthymiopoulos. Farheena Yasmeen Rasheed, Office of the Solicitor, United States Patent and Trademark Office.

MainStory: TopStory Patent FedCirNews

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