Equillium, Inc.

CERTIFICATE OF AMENDMENT OF THE

AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF EQUILLIUM, INC.

equillium, inc., a corporation organized and existing under the laws of the State of Delaware, hereby certifies as follows:

first: The name of this corporation is Equillium, Inc. (the “Company”).

second: The date on which the Company’s Certificate of Incorporation was originally filed with the Secretary of State of the State of Delaware is March 16, 2017. The Company was originally incorporated under the name Attenuate Biopharmaceuticals, Inc.

THIRD: The Board of Directors of the Company, acting in accordance with the provisions of Sections 141 and 242 of the General Corporation Law of the State of Delaware, adopted resolutions amending its Amended and Restated Certificate of Incorporation, as heretofore amended (the “Certificate of Incorporation”), as follows:

The Certificate of Incorporation is hereby amended by deleting Article IV Section A thereof and inserting the following in lieu thereof:

“A. The Company is authorized to issue two classes of stock to be designated, respectively, “Common Stock” and “Preferred Stock.” The total number of shares which the Company is authorized to issue is 410,000,000 shares. 400,000,000 shares shall be Common Stock, each having a par value of $0.0001. 10,000,000 shares shall be Preferred Stock, each having a par value of $0.0001.”

fourth: The foregoing amendment was submitted to the stockholders of the Company for their approval, and was duly adopted in accordance with the provisions of Section 242 of the General Corporation Law of the State of Delaware and shall be effective as of 5:00 p.m., Eastern time, on the business day following the filing of this Certificate of Amendment with the office of the Secretary of State of the State of Delaware.

in witness whereof, equillium, inc. has caused this Certificate of Amendment to be signed by its Chief Executive Officer this day of , 2026.

equillium, inc.

By:

Bruce D. Steel

Chief Executive Officer

Equillium C/O TABULATOR, P.O. BOX 8016, CARY, NC 27512-9903 Your vote matters! Have your ballot ready and please use one of the methods below for easy voting: Your control number Have the 12 digit control number located in the box above available when you access the website and follow the instructions. Equillium, Inc. Annual Meeting of Stockholders For Stockholders of record as of April 1, 2026 Thursday, May 28, 2026 1:00 PM, Pacific Time Annual Meeting to be held virtually via the internet - please visit www.proxydocs.com/EQ for more details YOUR VOTE IS IMPORTANT! PLEASE VOTE BY: 1:00 PM, Pacific Time, May 28, 2026. Internet: www.proxypush.com/EQ Cast your vote online Have your Proxy Card ready Follow the simple instructions to record your vote Phone: 1-855-680-7102 Use any touch-tone telephone Have your Proxy Card ready Follow the simple recorded instructions Mail: Mark, sign and date your Proxy Card Fold and return your Proxy Card in the postage-paid envelope provided Virtual: You must register to attend the meeting online and/or participate at www.proxydocs.com/EQ. This proxy is being solicited on behalf of the Board of Directors The undersigned hereby appoints Bruce D. Steel and Daniel M. Bradbury (the "Named Proxies"), and each or either of them, as the true and lawful attorneys of the undersigned, with full power of substitution and revocation, and authorizes them, and each of them, to vote all the shares of capital stock of Equillium, Inc. which the undersigned is entitled to vote at said meeting and any adjournment thereof upon the matters specified and upon such other matters as may be properly brought before the meeting or any adjournment thereof, conferring authority upon such true and lawful attorneys to vote in their discretion on such other matters as may properly come before the meeting and revoking any proxy heretofore given. THE SHARES REPRESENTED BY THIS PROXY WILL BE VOTED AS DIRECTED OR, IF NO DIRECTION IS GIVEN, SHARES WILL BE VOTED IDENTICAL TO THE BOARD OF DIRECTORS RECOMMENDATION. This proxy, when properly executed, will be voted in the manner directed herein. In their discretion, the Named Proxies are authorized to vote upon such other matters that may properly come before the meeting or any adjournment or postponement thereof. You are encouraged to specify your choice by marking the appropriate box (SEE REVERSE SIDE) but you need not mark any box if you wish to vote in accordance with the Board of Directors’ recommendation. The Named Proxies cannot vote your shares unless you sign (on the reverse side) and return this card. PLEASE BE SURE TO SIGN AND DATE THIS PROXY CARD AND MARK ON THE REVERSE SIDE Copyright © 2026 BetaNXT, Inc. or its affiliates. All Rights Reserved

Equillium Equillium, Inc. Annual Meeting of Stockholders Please make your marks like this: THE BOARD OF DIRECTORS RECOMMENDS A VOTE: FOR both the nominees for director listed below and FOR Proposals 2, 3 and 4. PROPOSAL YOUR VOTE BOARD OF DIRECTORS RECOMMENDS 1. To elect the Board's two nominees for Class II director named as nominees in the Proxy Statement to hold office until the 2029 Annual Meeting of Stockholders and their successors are duly elected and qualified, or until their earlier death, resignation or removal; 1.01 Charles McDermott 1.02 Bruce D. Steel FOR WITHHOLD FOR FOR 2. To approve an amendment to our Amended and Restated Certificate of Incorporation to effect a reverse stock split of our common stock at a ratio in the range of 1-for-2 to 1-for-20, inclusive, with such ratio to be determined in the discretion of our Board of Directors and with such reverse stock split to be effected at such time and date, if at all, as determined by our Board of Directors in its sole discretion; 3. To ratify the appointment by the Audit Committee of the Board of Crowe LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2026; FOR FOR 4. To approve an amendment to the Company's Amended and Restated Certificate of Incorporation to increase the authorized number of shares of common stock from 200,000,000 to 400,000,000 shares; and 5. To conduct any other business properly brought before the Annual Meeting. You must register to attend the meeting online and/or participate at www.proxydocs.com/EQ. Authorized Signatures - Must be completed for your instructions to be executed. Please sign exactly as your name(s) appears on your account. If held in joint tenancy, all persons should sign. Trustees, administrators, etc., should include title and authority. Corporations should provide full name of corporation and title of authorized officer signing the Proxy/Vote Form. Signature (and Title if applicable) Date Signature (if held jointly) Date