On September 9, 2022, Biogen Inc. and Biogen MA Inc. (“Plaintiffs”) filed suit against Sandoz Inc., Sandoz International GMBH, Sandoz GMBH, and Polpharma Biologics S.A. (collectively, “Defendants”) in the District of Delaware concerning twenty-eight different patents. Although the complaint was filed under seal, the complaint appears to be related to Defendants’ natalizumab biosimilar (proprietary name of Tysabri®).  Sandoz announced on July 25, 2022 that the FDA had accepted its aBLA for natalizumab.  Biogen’s twenty-eight asserted patents have not yet been listed in the Purple Book.  This suggests that either (1) Sandoz already provided its 180-day notice of commercial marketing under 42 USC § 262(l)(8)(A), or (2) Sandoz may have opted out of the patent dance by refusing to produce its aBLA and associated documents (see § 262(l)(9)). On September 12, Judge Connolly granted Plaintiffs motion to file the complaint under seal. The order requires Biogen to file a redacted version of the complaint by September 19, which will then provide more details on the BPCIA litigation.  We will provide further updates as the case progresses.