Item 1.01 — Entry into a Material Definitive Agreement

A new material agreement was signed — financing facility, partnership, license, or major contract.

CVR Agreement As previously disclosed, on March 31, 2026, Biogen Inc., a Delaware corporation (“Biogen”), entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Apellis Pharmaceuticals, Inc., a Delaware corporation (“Apellis”), and Aspen Purchaser Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Biogen (“Purchaser”). Pursuant to the Merger Agreement and in connection with the irrevocable acceptance for payment by Purchaser of all outstanding shares of common stock, par value $0.0001 per share, of Apellis (the “Shares”) validly tendered and not validly withdrawn pursuant to the Offer (as defined below), on May 14, 2026, Biogen, Apellis and Equiniti Trust…

Item 2.01 — Completion of Acquisition or Disposition of Assets

An acquisition or disposition closed (assets, business unit, or whole subsidiary).

Pursuant to the Merger Agreement, on April 14, 2026, Purchaser commenced a tender offer (the “Offer”) to acquire any and all of the issued and outstanding Shares, in exchange for (i) $41.00 per Share, net to the seller in cash, without interest and subject to reduction for any applicable tax withholding (the “Cash Amount”), plus (ii) one contractual, non-transferable contingent value right per Share (each, a “CVR”) representing the right to receive contingent cash payments of up to an aggregate of $4.00 in cash, without interest and subject to reduction for any applicable tax withholding, upon the achievement of certain specified milestones (the Cash Amount plus one CVR, collectively, the…

Item 2.03 — Creation of a Direct Financial Obligation

A new debt obligation was incurred — credit facility, convertible note, term loan, or guarantee.

or an Obligation under an Off-Balance Sheet Arrangement. The information set forth in

Item 7.01 — Regulation FD Disclosure

Voluntarily-disclosed material information under Regulation FD (e.g., investor presentation, conference talk).

and in Exhibit 99.1 of this Current Report on Form 8-K shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be incorporated by reference into any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01 — Financial Statements and Exhibits

Press releases, exhibits, and supporting documents attached to this filing.