Xifaxan® (rifaximin)
Case Name: Norwich Pharms., Inc. v. Kennedy, Jr., No. 23-5311, 2026 WL 1838966 (D.C. Cir. June 26, 2026) (Circuit Judges Pillard, Walker, and Garcia presiding; Opinion by Walker, J.) (Appeal from D.D.C., Howell, J.)
Drug Product and Patent(s)-in-Suit: Xifaxan® (rifaximin)
Nature of the Case and Issue(s) Presented: Following patent litigation in the District of Delaware, the district court entered judgment under 35 U.S.C. § 271(e)(4)(A) ordering that FDA final approval of Norwich’s ’369 ANDA could not become effective until expiration of Salix’s hepatic encephalopathy patents in October 2029. After judgment, Norwich amended its pending ANDA to carve out the infringing hepatic encephalopathy indication and sought final FDA approval of the amended application. FDA instead granted only tentative approval, concluding that the Delaware judgment barred final approval of ANDA No. 214369—whether amended or not—until 2029. Norwich challenged FDA’s decision under the APA, arguing that the agency acted arbitrarily and capriciously by interpreting the Delaware judgment to apply to the amended ANDA. The district court granted summary judgment to FDA and Salix, and the D.C. Circuit affirmed.
Why FDA and Salix Prevailed: The D.C. Circuit held that FDA correctly interpreted the Delaware district court’s final judgment according to its plain language. The judgment specifically identified the ’369 ANDA and ordered that “any final approval” of that application could not become effective before October 2029. Because Norwich’s amended submission remained the same ANDA identified by number, FDA reasonably concluded that the amended application remained subject to the injunction delaying final approval.
The D.C. Circuit further explained that the litigation history confirmed this reading. Before entry of final judgment, Norwich expressly requested language that would have allowed FDA to approve an amended ANDA excluding the infringing indication, but the Delaware district court rejected that proposal. After judgment, Norwich itself repeatedly argued in its Rule 60(b) motion that the existing judgment prohibited FDA approval of its amended ANDA and asked the court to modify the judgment to remove that restriction. The Delaware court denied that request, and the Federal Circuit subsequently interpreted the same judgment as delaying approval of the entire ANDA until 2029 while noting that Norwich remained free to file a new, non-infringing ANDA. Against that backdrop, the D.C. Circuit concluded that Norwich’s current interpretation improperly sought to read into the judgment language the Delaware court had twice declined to include.
The D.C. Circuit also rejected Norwich’s reliance on Ferring B.V. v. Watson Laboratories, Inc.-Florida, 764 F.3d 1382 (Fed. Cir. 2014). Unlike Ferring, where the generic applicant committed during the infringement litigation to amend its ANDA and the district court expressly addressed the amended application in its judgment, Norwich amended its ANDA only after trial and entry of final judgment. Because the Delaware court deliberately declined to distinguish between the original and amended versions of ANDA No. 214369, Ferring did not support Norwich’s position.
