Bausch Health unit prevails in patent dispute
New Jersey court dismissed a suit regarding an oral antibiotic | Prior art invalidated plaintiff’s four patents.
The US District Court for the District of New Jersey has dismissed a patent infringement suit brought against Bausch Health's Salix Pharmaceuticals over its drug Xifaxan (rifaximin).
In an opinion published yesterday, August 18, Judge Esther Salas found that Xifaxan actually constitutes prior art to the Curia IP patents it was accused of infringing.
In 2021, Curia IP accused Salix of infringing four patents covering claims directed to mixtures containing certain ratios of the α and β polymorphic forms of rifaximin. According to the suit, Salix’s sale of Xifaxan, specifically for those sold after November 2015, infringe the four patents.
Salix sought to dismiss the suit, claiming that Curia IP’s allegations confirm that Xifaxan was on sale prior to their patent applications and so constitutes prior art and triggers the on-sale bar.
Curia IP’s earliest patent filing date is 2013.
In response, Curia IP claimed that the “accused products” consist of Xifaxan manufactured after November 17, 2015 but didn’t allege that the accused products differ from the drug product manufactured before this time.
“As noted, defendants argue that plaintiff’s complaint, as pled, admits that Xifaxan was manufactured and sold prior to the date of the first filed patent application. In light of that admission, defendants argue that their product is necessarily prior art and therefore invalidates plaintiff’s four patents. The court agrees,” said Salas.
The court dismissed Curia IP’s complaint without prejudice, noting that the facts of the case not yet alleged may support the plausible inference that the two forms of XIFAXAN (pre-2015 and post-2015) are distinct under Tate Access Floors v Interface Architectural Res.
In Tate, the US Court of Appeals for the Federal Circuit rejected the argument that prior art existed through textbook teachings on beveling, or sloping, the edges of laminate.
According to the court, these textbook teachings applied to contexts outside of the one outlined within the relevant patent so, where you can distinguish between the alleged prior art and the accused product, the plaintiff’s product is not subject to the on-sale bar.
After dismissing the case without prejudice, Salas added: "Defendants argue that any amendment to the existing complaint would be sought in bad faith because it would contradict facts alleged in the complaint.
“But even assuming contradictory facts would be required, and it is not clear they would be, amended pleadings may contradict prior pleadings even if for the purpose of surviving a renewed motion to dismiss.”
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