Passage BIO Inc

Proposed Amendment to the Restated Certificate of Incorporation

CERTIFICATE OF AMENDMENT TO THE

RESTATED CERTIFICATE OF INCORPORATION

OF

PASSAGE BIO, INC.

Passage Bio, Inc. (the “Corporation”), a corporation organized and existing under and by virtue of the General Corporation Law of the State of Delaware (the “DGCL”), does hereby certify as follows:

“Effective at 12:01 a.m. Eastern Daylight Time on [●], 2025 (the “Effective Time”), each [●] ([●]) shares of Common Stock then issued and outstanding, or held in treasury of the Corporation, immediately prior to the Effective Time shall automatically be reclassified and converted into one (1) share of Common Stock, without any further action by the Corporation or the respective holders of such shares (the “Reverse Stock Split”). No fractional shares shall be issued in connection with the Reverse Stock Split. A holder of Common Stock who would otherwise be entitled to receive a fractional share of Common Stock as a result of the Reverse Stock Split will receive one whole share of Common Stock in lieu of such fractional share.”

[Signature appears on the following page.]

IN WITNESS WHEREOF, the Corporation has caused this Certificate of Amendment to be signed by its duly authorized officer this [●] day of [●], 2025.

Signature [PLEASE SIGN WITHIN BOX] Date Signature (Joint Owners) Date TO VOTE, MARK BLOCKS BELOW IN BLUE OR BLACK INK AS FOLLOWS: KEEP THIS PORTION FOR YOUR RECORDS DETACH AND RETURN THIS PORTION ONLY THIS PROXY CARD IS VALID ONLY WHEN SIGNED AND DATED. 01) Maxine Gowen, Ph.D. 02) Dolan Sondhi, Ph.D. Nominees: 2. To ratify the appointment of KPMG LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2025. 3. To approve an amendment to the Company's Restated Certificate of Incorporation to effect a reverse stock split of the Company's outstanding shares of common stock at a ratio of any whole number between 1-for-5 and 1-for-50, with the exact ratio determined by the Board of Directors in its discretion, subject to the Board of Directors' authority to abandon such amendment. 1. To elect two Class II directors, each to serve a three-year term through the third Annual Meeting of Stockholders following this meeting and until a successor has been elected and qualified or until earlier resignation or removal. PASSAGE BIO, INC. The Board of Directors recommends you vote FOR the following: The Board of Directors recommends you vote FOR the following proposals: Please sign exactly as your name(s) appear(s) hereon. When signing as attorney, executor, administrator, or other fiduciary, please give full title as such. Joint owners should each sign personally. All holders must sign. If a corporation or partnership, please sign in full corporate or partnership name by authorized officer. 4. Any such other business as may properly come before the meeting or any adjournment thereof. PASSAGE BIO, INC. ONE COMMERCE SQUARE 2005 MARKET STREET 39TH FLOOR PHILADELPHIA, PA 19103 VOTE BY INTERNET Before The Meeting - Go to www.proxyvote.com or scan the QR Barcode above Use the Internet to transmit your voting instructions and for electronic delivery of information up until 11:59 PM Eastern Time on May 27, 2025. Have your proxy card in hand when you access the web site and follow the instructions to obtain your records and to create an electronic voting instruction form. During The Meeting - Go to www.virtualshareholdermeeting.com/PASG2025 You may attend the meeting via the Internet and vote during the meeting. Have the information that is printed in the box marked by the arrow available and follow the instructions. VOTE BY PHONE - 1-800-690-6903 Use any touch-tone telephone to transmit your voting instructions up until 11:59 PM Eastern Time on May 27, 2025. Have your proxy card in hand when you call and then follow the instructions. VOTE BY MAIL Mark, sign and date your proxy card and return it as soon as possible before the Annual Meeting in the postage-paid envelope we have provided or return it to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717. V69490-P26463 ! ! ! For All Withhold All For All Except For Against Abstain ! ! ! ! ! ! To withhold authority to vote for any individual nominee(s), mark "For All Except" and write the number(s) of the nominee(s) on the line below. SCAN TO VIEW MATERIALS & VOTEw

V69491-P26463 PASSAGE BIO, INC. Annual Meeting of Stockholders May 28, 2025 9:00 AM, Eastern Time This proxy is solicited by the Board of Directors The stockholder(s) hereby appoint(s) William Chou, M.D. and Kathleen Borthwick as proxies, each with power to act without the other and each with the power to appoint their substitute, and hereby authorize(s) them to represent and to vote, as designated on the reverse side of this ballot, all of the shares of Common Stock of PASSAGE BIO, INC. that the stockholder(s) is/are entitled to vote at the Annual Meeting of Stockholders to be held at 9:00 AM, Eastern Time on May 28, 2025, virtually at www.virtualshareholdermeeting.com/PASG2025, and any adjournment or postponement thereof. This proxy, when properly executed, will be voted in the manner directed herein. If no such direction is made, this proxy will be voted in accordance with the Board of Directors' recommendations. Continued and to be signed on reverse side Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting: The Notice and Proxy Statement and Annual Report are available at www.proxyvote.com.