This Amendment No. 1 (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 (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 Alpines common stock, par value $0.001 per share (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 3. Past Contacts, Transactions, Negotiations and Agreements
The subsection of Item 3 of the Schedule 14D-9 entitled Arrangements with Current Executive Officers and Directors of Alpine
Consideration for Shares Tendered Pursuant to the Offer is hereby amended as follows:
On page 9, the first full paragraph is amended and
restated as follows (new language underlined):
The following table sets forth the consideration that each Alpine executive officer and director and
his or her affiliates would be entitled to receive in respect of outstanding Shares beneficially owned by him, her or it as of April 18, 2024 (which, for clarity, excludes Shares underlying Alpine Equity Compensation Awards, the Alpine
Pre-Funded Warrants and the Other Company Warrants), assuming such individual and his or her affiliates were to tender all of his or her outstanding Shares pursuant to the Offer and those Shares were accepted for purchase and purchased by Purchaser.
These numbers do not reflect any future Share issuances or dispositions that may occur between April 18, 2024 and the Effective Time. Alpine expects that the executive officers listed below will exercise certain of their vested Alpine Stock
Options prior to the Effective Time. For further information with respect to the treatment of Shares held by executive officers, see the information set forth in the section entitled Arrangements with Current Executive Officers and
Directors of AlpineConsideration for Shares Tendered Pursuant to the Offer.
Item 4. The Solicitation or Recommendation
The subsection of Item 4 of the Schedule 14D-9 entitled Opinion of Alpines Financial Advisor Summary of Centerview
Financial Analysis is hereby amended as follows:
On page 33, the second full paragraph is amended and restated as follows (new language
underlined; deleted language struck through):
In performing this analysis, Centerview calculated a range of equity values for the Shares by
(a) discounting to present value as of June 30, 2024 using discount rates ranging from 12.0% to 14.0% (based on Centerviews analysis of Alpines weighted average cost of capital using the Capital Asset Pricing Model and based
on considerations that Centerview deemed relevant in its professional judgment and experience and taking into account certain metrics including yields for U.S. treasury notes, levered and unlevered betas for comparable group companies, market risk
and size premia) and using a mid-year convention: (i) the forecasted risk-adjusted, after-tax unlevered free cash flows of Alpine over the period beginning on July 1, 2024 and ending on December 31, 2046, utilized by Centerview
based on the Projections, (ii) an implied terminal value of Alpine, calculated by Centerview by assuming that Alpines unlevered free cash flows set forth in the Projections would decline in perpetuity after December 31, 2046 at a
rate of free cash flow decline of 45% year over year, as