Mitchell Gold - 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 2) 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

Alpine BioVentures GP, LLC is the general partner of Alpine ImmunoSciences, L.P. Dr. Gold is a Managing Partner of Alpine BioVentures GP, LLC. Dr. Gold is also a limited partner of Alpine ImmunoSciences, L.P. By virtue of such relationships, Dr. Gold may be deemed to have voting and investment power with respect to the shares held by Alpine ImmunoSciences, L.P. and as a result may be deemed to have beneficial ownership of such shares.

Footnote F4

The Reporting Person disclaims beneficial ownership of the shares of common stock reported herein except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that the Reporting Person is the beneficial owner of such shares for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.

Footnote F5

Includes 96,000 shares of common stock underlying a restricted stock unit grant made on January 4, 2024 (the RSUs). One-fourth (1/4th) of the RSUs will vest on January 1, 2025 and the remainder will vest in twelve (12) equal quarterly installments on April 1, 2025, July 1, 2025, October 1, 2025 and on January 1, April 1, July 1, and October 1 of each subsequent year until all RSUs are vested on January 1, 2028, subject to Participant continuing to be a Service Provider through each such date.

Footnote F6

Pursuant to the Merger Agreement, as of immediately prior to the Effective Time, each restricted stock unit of the Company (a Company RSU) that was then outstanding but not then vested became immediately vested in full. At the Effective Time, each Company RSU was automatically cancelled and the holder thereof became entitled to receive an amount in cash, without interest thereon and subject to any applicable tax withholding, equal to the product obtained by multiplying (i) the number of shares of Common Stock underlying such Company RSU by (ii) the Merger Consideration.

Footnote F7

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 F8

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

Footnote F9

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 F10

(Continued from Footnote 9) 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 F11

One-fourth (1/4) of the shares subject to the option will vest on January 5, 2022, and one thirty-sixth (1/36th) of the remaining shares subject to the option shall vest each month thereafter, subject to Reporting Person continuing to be a service provider through each such date.

Footnote F12

One-fourth (1/4) of the shares subject to the option will vest on January 4, 2023, and one thirty-sixth (1/36th) of the remaining shares subject to the option shall vest each month thereafter, subject to Reporting Person continuing to be a service provider through each such date.

Footnote F13

One-fourth (1/4th) of the Shares subject to the Option will vest on January 4, 2024, and one thirty-sixth (1/36th) of the remaining Shares subject to the Option shall vest each month thereafter, subject to the Reporting Person continuing to be a service provider through each such date.

Footnote F14

One-fourth (1/4th) of the Shares subject to the Option will vest on January 4, 2025, and one thirty-sixth (1/36th) of the remaining Shares subject to the Option shall vest each month thereafter, subject to the Reporting Person continuing to be a service provider through each such date.