Xiangmin Cui - 18 May 2024 Form 4 Insider Report for ALPINE IMMUNE SCIENCES, INC.

Footnote F1

This Form 4 reports securities disposed of pursuant to the Agreement and Plan of Merger (the Merger Agreement), dated April 10, 2024, among Alpine Immune Sciences, Inc., a Delaware corporation (the Company), Vertex Pharmaceuticals Incorporated, a Massachusetts corporation (Parent), and Adams Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of the Parent (Merger Sub). Pursuant to the Merger Agreement, Merger Sub completed a tender offer for shares of the Companys Common Stock, par value $0.001 per share (Company Common Stock), effective May 18, 2024 (the Offer Closing), and thereafter merged with and into the Company (the Merger, and together with the Offer Closing, the Transactions), effective May 20, 2024 (the Effective Time), with the Company surviving the Merger as a wholly owned subsidiary of Parent.

Footnote F2

(Continued from Footnote 1) In connection with the consummation of the Transactions, each share of the Company Common Stock was either (x) purchased at the Offer Closing for $65.00 in cash per share (the Offer Price), without interest thereon and subject to any applicable tax withholding or (y) automatically converted in the Merger at the Effective Time into the right to receive the Offer Price in cash, without interest thereon (the Merger Consideration), subject to any applicable tax withholding.

Footnote F3

These securities are owned directly by Decheng Capital China Life Sciences USD Fund III, L.P. ("Fund III"). Xiangmin Cui is the manager of Decheng Capital Management III (Cayman), LLC, the general partner of Fund III. Dr. Cui disclaims beneficial ownership of these securities, except to the extent of his pecuniary interest therein.

Footnote F4

These securities are owned directly by Decheng Capital Global Healthcare Fund (Master), LP ("Healthcare"). Xiangmin Cui is the indirect managing member and ultimate beneficial owner of Decheng Capital Global Healthcare GP, LLC, the general partner of Healthcare. Dr. Cui disclaims beneficial ownership of these securities, except to the extent of his pecuniary interest therein.

Footnote F5

The exercise price is equal to the closing price per share of Common Stock as reported on the Nasdaq Global Market on the date of grant.

Footnote F6

The option to purchase shares of Company Common Stock (the Company Option) is fully vested and exercisable.

Footnote F7

Pursuant to the Merger Agreement, as of immediately prior to the Effective Time, each option to purchase shares of Company Common Stock (a Company Option) that was then outstanding but not then vested or exercisable became immediately vested and exercisable in full. At the Effective Time, each Company Option that was then outstanding was automatically cancelled and, if such Company Option had a per share exercise price less than the Merger Consideration, the holder thereof became entitled to receive a cash payment, without interest thereon and subject to any applicable tax withholding, equal to the product obtained by multiplying (i) the total number of shares of Company Common Stock underlying such Company Option by (ii) the excess of the Merger Consideration over the exercise price per share such Company Option.

Footnote F8

(Continued from Footnote 7) Any Company Option that had an exercise price per share that was equal to or exceeded the Merger Consideration was cancelled without any cash payment or other consideration being made in respect thereof.

Footnote F9

1/12th of the shares subject to the option become vested and exercisable on February 2, 2024 and 1/12 of the shares subject to the option shall vest monthly thereafter.