United States Court of Appeals for the Federal Circuit ______________________

SALIX PHARMACEUTICALS, LTD., SALIX PHARMACEUTICALS, INC., BAUSCH HEALTH IRELAND LTD., ALFASIGMA S.P.A., Plaintiffs-Appellants

v.

NORWICH PHARMACEUTICALS INC., Defendant-Cross-Appellant ______________________

2022-2153, 2023-1952 ______________________

Appeals from the United States District Court for the District of Delaware in No. 1:20-cv-00430-RGA, Judge Richard G. Andrews. ______________________

Decided: April 11, 2024 ______________________

WILLIAM R. PETERSON, Morgan, Lewis & Bockius LLP, Houston, TX, argued for plaintiffs-appellants. Also repre- sented by MICHAEL J. ABERNATHY, KARON NICOLE FOWLER, MICHAEL SIKORA, Chicago, IL; JULIE S. GOLDEMBERG, Phil- adelphia, PA; JOSHUA DANIEL CALABRO, SHANNON KEOUGH CLARK, STEVEN C. KLINE, ALEXIS M. MCJOYNT, SCOTT K. REED, BECKY E. STEEPHENSON, Venable LLP, New York, NY.

CHAD A. LANDMON, Axinn, Veltrop & Harkrider LLP, Case: 22-2153 Document: 71 Page: 2 Filed: 04/11/2024

2 SALIX PHARMACEUTICALS, LTD. v. NORWICH PHARMACEUTICALS INC.

Hartford, CT, argued for defendant-cross-appellant. Also represented by MATTHEW BECKER, REBECCA L. CLEGG, THOMAS K. HEDEMANN, MATTHEW S. MURPHY.

IRENA ROYZMAN, Kramer Levin Naftalis & Frankel LLP, New York, NY, for amici curiae Regeneron Pharma- ceuticals, Inc., Ocular Therapeutix, Inc. Also represented by CHRISTINE WILLGOOS; PAUL BRZYSKI, Washington, DC.

PAUL WHITFIELD HUGHES, III, McDermott Will & Em- ery LLP, Washington, DC, for amicus curiae Vanda Phar- maceuticals Inc. Also represented by CHRISTOPHER MICHAEL BRUNO, SARAH HOGARTH, APRIL ELISE WEISBRUCH. ______________________

Before LOURIE, CHEN, and CUNNINGHAM, Circuit Judges. Opinion for the court filed by Circuit Judge LOURIE. Opinion dissenting-in-part filed by Circuit Judge CUNNINGHAM. LOURIE, Circuit Judge. Salix Pharmaceuticals, Ltd., Salix Pharmaceuticals, Inc., Bausch Health Ireland Ltd., and Alfasigma S.P.A. (collectively, “Salix”) appeal from a final judgment of the United States District Court for the District of Delaware holding claim 2 of U.S. Patent 8,309,569, claim 3 of U.S. Patent 10,765,667, claim 4 of U.S. Patent 7,612,199, and claim 36 of U.S. Patent 7,902,206 invalid as obvious. See Salix Pharms., Ltd. v. Norwich Pharms., Inc., No. 20-cv- 430, 2022 WL 3225381 (D. Del. Aug. 10, 2022) (“Decision”). Norwich Pharmaceuticals Inc. (“Norwich”) cross-ap- peals from an order that issued after the district court con- cluded that Norwich infringed claim 8 of U.S. Patent 8,624,573, claim 6 of U.S. Patent 9,421,195, and claims 11 and 12 of U.S. Patent 10,335,397 and had failed to prove Case: 22-2153 Document: 71 Page: 3 Filed: 04/11/2024

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that those claims were invalid. That order, contained within the final judgment, instructed the FDA that the ef- fective approval date of Norwich’s Abbreviated New Drug Application (“ANDA”) may not precede the expiration dates of those claims. J.A. 51. Norwich also cross-appeals from a denial of its motion to modify the final judgment. See Salix Pharms., Ltd. v. Norwich Pharms., Inc., No. 20-430, 2023 WL 3496373 (D. Del. May 17, 2023) (“Rule 60(b) Or- der”). For the following reasons, we affirm. BACKGROUND Rifaximin, the active ingredient in Salix’s commercial product Xifaxan®, has been widely used as an antibiotic for decades, having been first synthesized in the early 1980s in Italy and approved there as an antibiotic in 1985. Deci- sio