Making the obvious nonobvious isn’t as simple as observing something others have missed, the U.S. Court of Appeals for the Federal Circuit reiterated in a precedential opinion last week. 

The opinion upheld a lower court’s decision in Persion Pharmaceuticals LLC v. Alvogen Inc. that overturned two patents claiming methods of treating pain in patients with mild or moderate liver impairment using extended-release hydrocodone-only formulations, including Zohydro ER.  

When the now-bankrupt Pernix Therapeutics LLC sought FDA approval for Zohydro ER several years ago, the agency required a clinical study to determine the potential effect of the drug on patients with impaired liver function. After trial results showed that the drug didn’t result in substantially higher concentrations of hydrocodone in the bloodstream of patients with mild and moderate hepatic impairment than in those without liver problems, Pernix filed for the ’760 and ’499 patents claiming that discovery. 

Before the patents issued, Alvogen, of Pine Brook, N.J., submitted an abbreviated new drug application for a Zohydro generic. That triggered Pernix’s infringement suit in the U.S. District Court for the District of Delaware as soon as the patents were awarded. 

Although the district court recognized the unexpected results from the clinical trial, the “long-felt but unmet need” and the failure of other researchers, it ruled in 2018 that those factors did not outweigh the patents’ obviousness due to prior art. 

The Federal Circuit agreed, citing a Supreme Court acknowledgment that “[i]t is not invention to perceive that the product which others had discovered had qualities they failed to detect.”  

The Federal Circuit added, “To hold otherwise would allow any formulation – no matter how obvious – to become patentable merely by testing and claiming an inherent property.” 

Persion, of Morristown, N.J., acquired Zohydro and the patents last year after Pernix filed for bankruptcy. Both patents were set to expire in July 2033, according to the FDA Orange Book. 

However, the Orange Book lists about a dozen other patents for Zohydro that don’t expire until 2033 or 2034. 

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