Rifaximin – USA

Rifaximin – USA

On Aug. 17, 2022, New Jersey court granted Defendant’s motion to dismiss the complaint.

 

Plaintiff (Curia IP) is the assignee of patents related to mixtures of α and β polymorphic forms of rifaximin. These are US 9,186,355; US 10,556,915; US 10,745,415; and US 10,961,257 which have filing date in 2013 & 2014. Defendants (Salix pharma / Bausch / Alfasigma) markets XIFAXAN® product in USA since July 2004. Plaintiff claims that Defendants’ sale of XIFAXAN®, specifically for those sold after November 2015, infringe the four patents referenced above. According to Plaintiff, the accused products “contained only the α polymorphic form of rifaximin at the time of manufacture,” and this form “partially converts to the β polymorphic form during storage, transportation and other handling, resulting in the mixture that falls within the scope of the claims”. While Plaintiff limits the accused products to XIFAXAN® manufactured after November 17, 2015, Plaintiff does not allege that the accused products differ from XIFAXAN® manufactured before November 2015.

 

Defendants moved to dismiss the complaint arguing that as per Plaintiffs submission the product was ‘on-sale’ prior to patent filing date and thus is a prior art and therefore invalidates Plaintiff’s four patents. Court agreed and found that a defendant satisfies its burden under the on-sale bar based solely on the plaintiff’s own admissions. Merely because Plaintiff limits its infringement claim to post-2015 products does not mean Plaintiff alleges a distinction between pre- and post-2015 XIFAXAN®. Nothing in the Complaint does so, and in fact the Complaint appears to suggest that pre- and post-2015 XIFAXAN® contained just the α polymorph. “There is no allegation in the complaint that the laws of nature applicable to the α form in the later-sold tablets would have applied any differently to the α form in the earlier-sold tablets.”

 

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