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# Dismiss Norwich Rifaximin Suit: FDA
- URL: https://www.fdaweb.com/dismiss-norwich-rifaximin-suit-fda/
- Published: 2023-07-20T12:00:00.000Z
- Updated: 2026-09-14T18:45:31.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5154917

FDA is asking the DC federal court to dismiss a suit brought against the agency by Norwich Pharmaceuticals in an attempt to force FDA to approve the company’s amended ANDA for a generic form of rifaximin (Salix’ Xifaxan), to treat irritable bowel syndrome with diarrhea. In filing the suit, Norwich [said](https://www.fdaweb.com/norwich-sues-fda-over-rifaximin-anda/) FDA’s refusal violated the Administrative Procedures Act and was arbitrary, capricious, and unlawful.

The suit noted that the Delaware federal court ruled in 8/2022 that the proposed labeling in Norwich’s original ANDA for a reduction in the risk of overt hepatic encephalopathy (HE) recurrence in adults would induce the infringement of four claims from three Salix method of use patents.

Norwich says it amended the ANDA to carve out the HE indication and no longer seeks approval for it. “FDA based its decision to not grant final approval to Norwich’s amended ANDA on the order from the Delaware district court,” the company said. “But that decision is irrelevant because Norwich’s amended ANDA does not seek approval for the HE indication…. FDA should therefore have granted final approval to Norwich’s amended ANDA.”

In its response to the Norwich suit, FDA [says](http://www.fdaweb.com/download.php?file=fda%5Fcourt%5F7-19-23.pdf) Norwich tried but failed to persuade the Delaware federal court to modify its order to permit immediate approval of labeling that carved out the HE indication. “Norwich now sues FDA for complying with the patent orders by delaying final approval for its generic rifaximin product,” FDA says. “What’s more, it asks this court for mandatory injunctive relief that would directly clash with the Delaware court’s order.

The FDA response lists five reasons why the court should dismiss the Norwich suit:

- Norwich lacks standing because its claimed injuries are traceable to the Delaware court;
- Norwich’s claim is an impermissible collateral attack on the valid judgment of another district court;
- Norwich has no cause of action under the Administrative Procedures Act because the company has an adequate alternative remedy by appealing the Delaware court decision to the Federal Circuit Court of Appeals, which it is doing;
- FDA’s decision to follow a binding federal court order was not arbitrary, capricious, or unlawful; and
- Norwich should not be granted an injunction because it cannot succeed on the merits, has not shown a likelihood of irreparable harm without interim relief, and both the balance of equities and the public interest weigh heavily against the drastic change to the status quo Norwich is seeking.