On January 15, 2025, Celltrion filed IPR2025-00456 against Regeneron’s U.S. Patent No. 11,084,865 (“the ’865 patent”), challenging claims 1-17, 19-42, 44-50 as anticipated and claims 1-50 as obvious.  The claims are directed to ophthalmic formulations of a vascular endothelial growth factor (VEGF) antagonist suitable for intravitreal administration in vials and pre-filled syringes.  Many of the same claims have also been challenged by Samsung Bioepis (IPR2025-00176) and Formycon (IPR2025-00233, joinder requested with IPR2025-00176), and are awaiting an institution decision (previously reported Biosimilar Updates: EYLEA^® IPR Filings, Herceptin^® Biosimilar Hercessi™ Launch, Stelara^® Biosimilar Yesintek™ Approval).

Regeneron has asserted the ’865 patent against Celltrion’s proposed EYLEA^® (aflibercept) biosimilar CT-P42 in ongoing Case Nos. 1:23-cv-00089 (N.D.W. Va.) and 1:24-cv-00053 (N.D.W. Va.) / MDL 1:24-md-03103 (N.D.W. Va.), and a preliminary injunction was issued, which has been appealed (CAFC Appeals 24-2058 and 24-2147 ongoing) (previously reported Preliminary Injunctions Issued Preventing Launch of EYLEA^® Biosimilars).

Claims 4, 7, 9, 11, 14-17 of the ’865 patent were previously found not invalid (Case No. 1:22-cv-00061 (N.D.W. Va.) / MDL 1:24-md-03103 (N.D.W. Va.)) in Regeneron’s litigation against Biocon and Mylan’s Yesafili™ (aflibercept-jbvf) (previously reported Permanent Injunction Issued Preventing Launch of EYLEA^® Biosimilar Yesafili™), which has been appealed (ongoing).

Regeneron reported EYLEA^® sales of $5.72 billion in 2023.

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The author would like to thank April Breyer Menon for her contributions to this article.