United States Court of Appeals for the Federal Circuit ______________________

AZURITY PHARMACEUTICALS, INC., Plaintiff-Appellant

v.

ALKEM LABORATORIES LTD., Defendant-Appellee ______________________

2023-1977 ______________________

Appeal from the United States District Court for the District of Delaware in No. 1:20-cv-01094-MSG, Chief Judge Mitchell S. Goldberg. ______________________

Decided: April 8, 2025 ______________________

TUNG ON KONG, Wilson, Sonsini, Goodrich & Rosati, PC, San Francisco, CA, argued for plaintiff-appellant. Also represented by WENDY L. DEVINE; KELSEY CURTIS, RICHARD TORCZON, Washington, DC.

ALAN HENRY POLLACK, Windels Marx Lane & Mitten- dorf, LLP, Madison, NJ, argued for defendant-appellee. Also represented by KIERSTEN AMANDA FOWLER, JOSHUA I. MILLER. ______________________ Case: 23-1977 Document: 38 Page: 2 Filed: 04/08/2025

2 AZURITY PHARMACEUTICALS, INC. v. ALKEM LABORATORIES LTD.

Before MOORE, Chief Judge, CHEN, Circuit Judge, and MURPHY, District Judge. 1 MURPHY, District Judge. This appeal arises from a suit under the Hatch-Wax- man Act. Azurity Pharmaceuticals, Inc. (“Azurity”) brought suit against Alkem Laboratories Ltd. (“Alkem”) for infringement of claims 5, 7, 8, and 9 of U.S. Patent No. 10,959,948 (“the ’948 patent”) following Alkem’s submis- sion of an Abbreviated New Drug Application (“ANDA”). After a two-day bench trial, the court found that Alkem’s ANDA did not infringe any of the asserted claims of the ’948 patent. Azurity Pharms., Inc. v. Alkem Lab’ys, Ltd., 671 F. Supp. 3d 489 (D. Del. 2023). Because the district court correctly found that Azurity disclaimed any presence of propylene glycol in the prosecution history of the ’948 patent, Alkem’s ANDA product contains propylene glycol, and a stipulation entered by the parties during discovery does not preclude Alkem’s disclaimer argument, we affirm. BACKGROUND Azurity’s ’948 patent is directed to non-sterile drinka- ble liquid formulations containing the antibiotic vancomy- cin and methods for using those formulations to treat Clostridium difficile infection. ’948 patent, Abstract; id. at col. 1, ll. 21–25. Drinkable liquid drugs are particularly useful for treating pediatric and geriatric populations be- cause they present a lower choking risk than capsules and, unlike injections, do not require sterilization. Id. at col. 5, ll. 31–55; id. at col. 6, ll. 1–17. Claim 5 of the ’948 patent is representative and is re- produced below:

1 Honorable John F. Murphy, District Judge, United States District Court for the Eastern District of Pennsylva- nia, sitting by designation. Case: 23-1977 Document: 38 Page: 3 Filed: 04/08/2025

AZURITY PHARMACEUTICALS, INC. v. 3 ALKEM LABORATORIES LTD.

5. A non-sterile stable liquid formulation formu- lated for oral administration, consisting of: a buffering agent, wherein the buffering agent is selected from the group consisting of citric acid, sodium citrate, sodium tar- tarate, sodium acetate, sodium carbonate, sodium polyphosphate, potassium poly- phosphate, sodium pyrophosphate, potas- sium pyrophosphate, disodium hydrogen phosphate, trisodium phosphate, tripotas- sium phosphate, sodium acetate, potas- sium metaphosphate, magnesium oxide, magnesium carbonate, magnesium silicate, calcium acetate, calcium glycerophosphate, calcium chloride, calcium hydroxide, cal- cium lactate, calci