IP Law Daily, PATENT—D. Del.: Preliminary injunction denied in monoclonal antibody dispute, (May 13, 2024)

By Kevin M. Finson

The extraordinary remedy of a preliminary injunction was not appropriate because there were substantial questions about the validity of the asserted patent claims.

A drug manufacturer failed to show a likelihood of success on the merits in its infringement claims against a competitor’s biosimilar monoclonal antibody treatment, the federal district court in Wilmington, Delaware, has held. Substantial questions existed as to the validity of the asserted patent claims, including an ongoing an inter partes review proceeding as to one patent (Alexion Pharmaceuticals, Inc. v. Samsung Bioepis Co. Ltd. , No. 1:24-cv-00005-GBW (D. Del. May 3, 2024)).

Alexion Pharmaceuticals, Inc. and Alexion Pharma International Operations, Ltd. (collectively, Alexion) were the owners of U.S. Patents Nos. 9,447,176 (the ’176 patent) and 10,590,189 (the ’189 patent). Both patents claimed the use of a monoclonal antibody called SOLIRIS (eculizumab); Claim 1 of the ’189 patent for treating paroxysymal nocturnal hemoglobinuria (PNH) and Claim 1 of the ’176 patent for treating atypical hemolytic uremic syndrome (aHUS).

Samsung Bioepis Co., Ltd. (Samsung) applied for FDA approval of a SOLIRIS biosimilar, and Alexion brought suit for infringement under the Biologics Price Competition and Innovation Act (BPCIA). Alexion sought a preliminary injunction to prevent Samsung from marketing its biosimilar drug based on Claim 1 of each of the asserted patents.

Likelihood of success on the merits. The court noted that an inter partes review proceeding had been instituted by the Patent Trial and Appeal Board (PTAB) as to the ’189 patent. This was itself a substantial question of validity because the PTAB would have engaged in extensive analysis of the validity of the claim and found a reasonable likelihood of invalidity prior to instituting review. Absent any compelling evidence from Alexion that the PTAB was in error in instituting review, this meant there could not be a likelihood of success as to that patent.

As to the ’176 patent, Samsung argued that a person of ordinary skill in the art would be motivated use eculizumab to treat aHUS based on a combination of two prior art references, one of which expressly suggested using eculizumab. The court found that because the prior art references spelled out exactly how eculizumab was expected to interact with the known mechanism of the disease, there was at least a substantial question of validity.

Finding there was not a likelihood of success on the merits as to the claims for both asserted patents, the court denied the preliminary injunction without reaching the remaining factors.

The Case is No. 1:24-cv-00005-GBW.

Judge: Williams, G.

Attorneys: Daniel M. Silver (McCarter & English, LLP) for Alexion Pharmaceuticals, Inc. Andrew Colin Mayo (Ashby & Geddes P.A.) for Samsung Bioepis Co Ltd.

Companies: Alexion Pharmaceuticals, Inc.; Samsung Bioepis Co. Ltd.

Cases: Patent DelawareNews