Case: 23-1540 Document: 35 Page: 1 Filed: 09/14/2023

NOTE: This disposition is nonprecedential.

United States Court of Appeals for the Federal Circuit ______________________

AZURITY PHARMACEUTICALS, INC., Plaintiff-Appellant

v.

ALKEM LABORATORIES LTD., Defendant-Appellee ______________________

2023-1540 ______________________

Appeal from the United States District Court for the District of Delaware in No. 1:19-cv-02100-MSG, Judge Mitchell S. Goldberg. ______________________

Decided: September 14, 2023 ______________________

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

TIMOTHY H. KRATZ, Kratz & Barry LLP, Atlanta, GA, argued for defendant-appellee. Also represented by GEORGE BARRY, III; MICHAEL PATRICK HOGAN, Philadel- phia, PA; R. TOUHEY MYER, Wilmington, DE. ______________________ Case: 23-1540 Document: 35 Page: 2 Filed: 09/14/2023

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

Before DYK, HUGHES, and STOLL, Circuit Judges. DYK, Circuit Judge. Azurity Pharmaceuticals, Inc. (“Azurity”) appeals a de- cision of the United States district court for the District of Delaware determining that claims 16, 18, 22, 23, and 28 of U.S. Patent No. 10,786,482 and claims 4, 7, 17, and 18 of U.S. Patent No. 10,918,621 were invalid. We affirm. BACKGROUND The ’482 and ’621 patents claim liquid formulations of enalapril. Enalapril treats high blood pressure and has long been used in tablet form. Children and elderly pa- tients can have difficulty swallowing tablets, making the liquid form a useful alternative. The difficulty with a liquid form is that enalapril degrades in water. The ’482 and ’621 patents aim to remedy this and claim a liquid formulation that “maintains about 95% w/w or greater of the initial en- alapril amount at the end of a storage period of at least 12 months at about 5±3° C.” ’482 patent, col. 42 ll. 21–23. Alkem Laboratories, Ltd. (“Alkem”) submitted an Ab- breviated New Drug Application (“ANDA”). Azurity brought suit claiming the ANDA infringed the ’482 and ’621 patents. The district court agreed that the ANDA in- fringed, and that determination is not challenged on ap- peal. However, the district court also found the ’482 and ’621 patents were invalid due to obviousness and insuffi- cient written description. Azurity appeals. DISCUSSION “Obviousness is a mixed question of fact and law.” No- vartis AG v. Torrent Pharms. Ltd., 853 F.3d 1316, 1327 (Fed. Cir. 2017). The district court’s legal conclusion of ob- viousness is subject to de novo review, while “subsidiary factual findings are reviewed for substantial evidence.” Id. Substantial evidence is “such relevant evidence as a Case: 23-1540 Document: 35 Page: 3 Filed: 09/14/2023

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

reasonable mind might accept as adequate to support a conclusion.” Consol. Edison Co. v. NLRB, 305 U.S. 197, 229 (1938). We see no legal error in the district court’s obviousness determination and conclude that it was supported by sub- stantial evidence. Because we affirm the district court’s ob- viousness determination, we decline to reach the issue of written description. AFFIRMED