Xifaxan generic may be stalled until 2029 despite tentative FDA approval
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Although the FDA has granted tentative approval to Norwich Pharmaceuticals’ 200 mg generic rifaximin, Bausch Health asserted in a company statement that full approval will not be given until its own rifaximin patent expires in 2029.
Unlike the higher-dose formulations, the 200 mg dose of rifaximin (Xifaxan, Bausch Health), is only indicated for treatment of travelers’ diarrhea caused by noninvasive strains of Escherichia coli in patients aged older than 12 years.
“The Company understands this was a Paragraph III filing. A Paragraph III filing is made when an Abbreviated New Drug Application applicant does not intend to market its generic product until the patent expiration,” Bausch Health said in a press release. “The FDA will therefore not grant full approval until the expiry of the last of the Company’s Orange Book listed patents for the Xifaxan (rifaximin) 200 mg product on July 24, 2029.”
The Salix Pharmaceuticals arm of Bausch Health and Norwich Pharmaceuticals have been embroiled in a legal battle since 2020 over whether Norwich’s rifaximin product infringed on patents protecting Salix’s Xifaxan (rifaximin) 550 mg product, indicated for the treatment of irritable bowel syndrome with diarrhea and risk reduction for overt hepatic encephalopathy recurrence.
Salix contends that the Norwich generic infringed on six Xifaxan patents for the manufacturing process (U.S. Patent No. 7,902,206), crystalline forms of rifaximin (U.S. Patent No. 7,045,620), the treatment of bacterial infections (U.S. Patent No. 7,915,275), and the methods of maintaining hepatic encephalopathy remission (U.S. Patent No. 8,642,573, U.S. Patent No. 9,629,828 and U.S. Patent No. 10,314,828).
According to the FDA, the most common adverse events reported with rifaximin include hypersensitivity reactions, including exfoliative dermatitis, rash, angioneurotic edema, urticaria, flushing, pruritus and anaphylaxis.
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