On May 20, 2024, the FDA approved the first two interchangeable biosimilars of Regeneron’s EYLEA® (aflibercept)Biocon Biologics and Mylan’s Yesafili™ (aflibercept-jbvf) and Samsung Bioepis’s Opuviz™ (aflibercept-yszy).  There are at least three other pending aBLAs for EYLEA® biosimilars awaiting FDA approval, Celltrion’s CT-P42 (aBLA submitted to FDA in June 2023), Formycon’s FYB203 (aBLA accepted by FDA in August 2023), and Amgen’s ABP 938 (aBLA accepted by FDA in October 2023).

U.S. launch dates for Yesafili™ and Opuviz™ have not yet been announced, but Biocon has settled with Regeneron in Canada, with a launch date for Yesafili™ there no later than July 1, 2025.  Currently, Biocon and Samsung Bioepis are involved in a number of patent disputes with Regeneron in the U.S. and are under temporary restraining orders preventing the launch of the newly approved biosimilars.

Biocon and Mylan have two pending IPRs against Regeneron method of treatment patents (IPR2024-00201- U.S. Patent No. 10,888,601 and IPR2024-00298- U.S. Patent No. 11,253,572) that have been instituted and are awaiting Final Written Decisions.  Previous IPRs (IPR2021-00880- U.S. Patent No. 9,669,069, IPR2021-00881- U.S. Patent No. 9,254,338, IPR2022-01225- U.S. Patent No. 10,130,681, IPR2022-01226- U.S. Patent No. 10,888,601) led to Final Written Decisions finding all challenged claims unpatentable for four of Regeneron’s method of treatment patents related to EYLEA®, with appeals pending (see The PTAB Finds Claims of Two EYLEA® Patents Unpatentable and Regeneron Files its Sixth Complaint Against a Proposed EYLEA® Biosimilar).  IPR2023-00099 led to a disclaimer of method of treatment patent U.S. Patent No. 10,857,205.

In August 2022, Regeneron filed Case No. 1:22-cv-00061 (N.D.W. Va.) against Biocon and Mylan, alleging Yesafili™ infringes 24 of Regeneron’s patents.  After a bench trial, the Court issued a judgment on an initial subset of the asserted patents, finding some claims of Regeneron’s U.S. Patent No. 11,084,865 valid and infringed by Yesafili™.  It also found some claims of two other patents invalid and infringed (U.S. Patent Nos. 11,253,572 and 10,888,601) (see EYLEA® (aflibercept) and Soliris® (eculizumab) IPR and BPCIA Litigation Updates).  This case is currently pending as to other challenged patents.  On May 17, 2024, the Court issued a Temporary Restraining Order against launching Yesafili™ for 14 days from the entry of the Order.

Samsung Bioepis has three pending IPRs against Regeneron method of treatment patents (IPR2023-00442 – U.S. Patent No. 10,130,681, IPR2023-00739- U.S. Patent No. 10,888,601, and IPR2023-00884- U.S. Patent No. 11,253,572).  Previous IPRs led to a Final Written Decision finding challenged method of treatment claims unpatentable (IPR2023-00566- U.S. Patent No. 10,888,602, appeal pending), and the disclaimer of formulation claims of U.S. Patent No. 10,464,992 in IPR2023-01312.

Samsung Bioepis is involved in two litigations with Regeneron, Case Nos. 1:23-cv-00094 (N.D. W. Va.) and 1:23-cv-00106 (N.D. W. Va.), alleging Opuviz™ infringes a total of 52 of Regeneron’s patents (see EYLEA® (aflibercept) IPR and BPCIA Litigation Updates).  On May 17, 2024, the Court granted Regeneron’s request for a Temporary Restraining Order against the launch of Opuviz™ for 14 days after entry of the Order.

Regeneron reported EYLEA® sales of $5.89 billion in 2023.

We continue to monitor these cases.  For more information on these and other biosimilar patent disputes, please visit BiologicsHQ.



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


    Information contained in the Venable BiologicsHQ database relates to FDA-approved drug products listed in the CDER Purple Book or on the FDA website ( Information relating to FDA licensed products, FDA-approved indications, and aBLA and 505(b)(2) applications is obtained from public sources including the U.S. FDA website ( Information relating to litigations is given only for cases active from January 31, 2010 onward. Information relating to foreign biosimilar / biologics follow-on products approved in Australia, Canada, the E.U., Japan and South Korea is from public sources. Statistics graphics are compiled from information contained in the Venable BiologicsHQ database.


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