This Amendment No. 2 (this “Amendment”) to Schedule
14D-9 amends and supplements the Solicitation/Recommendation Statement on Schedule 14D-9 previously filed by Alpine Immune Sciences, Inc., a Delaware corporation
(“Alpine”), with the Securities and Exchange Commission (the “SEC”) on April 22, 2024 (together with any amendments and supplements thereto, the “Schedule
14D-9”), relating to the cash tender offer (the “Offer”) by Adams Merger Sub, Inc. (“Purchaser”), a Delaware corporation and wholly owned subsidiary of Vertex
Pharmaceuticals Incorporated, a Massachusetts corporation (“Vertex”), to purchase all of the issued and outstanding shares of Alpine’s common stock, par value $0.001 per share (the “Shares”), at a purchase
price of $65.00 per Share, net to the seller in cash, without interest thereon, and subject to any applicable tax withholding, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated as of April 22, 2024 (as may
be amended or supplemented from time to time, the “Offer to Purchase”) and the related Letter of Transmittal (as may be amended or supplemented from time to time, the “Letter of Transmittal”), and pursuant to the
Agreement and Plan of Merger, dated as of April 10, 2024, by and among Alpine, Vertex and Purchaser (as may be amended from time to time, the “Merger Agreement,” and the transactions contemplated therein, the
“Transactions”).
Except as otherwise set forth in this Amendment, the information set forth in the Schedule 14D-9 remains unchanged and is incorporated herein by reference to the extent relevant to the items in this Amendment. Capitalized terms used but not defined herein have the meanings ascribed to them in the Schedule
14D-9.
Item 8. Additional Information.
The subsection of Item 8 of the Schedule 14D-9 entitled “Regulatory Approvals—Antitrust Compliance”
is hereby amended as follows:
On page 47, the second full paragraph is amended and restated in its entirety as follows:
“On April 24, 2024, each of Alpine and Vertex filed its respective Premerger Notification and Report Forms with the FTC and the
Antitrust Division in connection with the purchase of Shares pursuant to the Offer. The required waiting period under the HSR Act with respect to the Offer and the Merger expired at 11:59 p.m., Eastern Time, on May 9, 2024. Accordingly, the
condition that the waiting period under the HSR Act applicable to the purchase of Shares pursuant to the Offer and the consummation of the Merger has either expired or been terminated, described in ‘Item 2—Identity and Background of Filing
Person—Tender Offer,’ has been satisfied.”