DEF 14A

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A
(RULE 14a-101)

SCHEDULE 14A INFORMATION
Proxy Statement Pursuant to Section 14(a) of the
Securities Exchange Act of 1934
(Amendment No. )

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

☐ Preliminary Proxy Statement

☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☒ Definitive Proxy Statement

☐ Definitive Additional Materials

☐ Soliciting Material under §240.14a-12

Definium Therapeutics, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

☒ No fee required.

☐ Fee paid previously with preliminary materials.

☐ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11.

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DEFINIUM THERAPEUTICS, INC.

One World Trade Center, Suite 8500
New York, New York 10007
(212) 220-6633

NOTICE OF ANNUAL GENERAL AND SPECIAL MEETING OF SHAREHOLDERS

To be held on June 11, 2026 at 10:00 a.m. Eastern Time.

Dear Shareholder:

You are cordially invited to attend the Annual General and Special Meeting of Shareholders (the “Annual Meeting”) of Definium Therapeutics, Inc. (the “Company” or “Definium”), a British Columbia company. All shareholders are invited to attend the Annual Meeting, which will be held virtually via live webcast at www.virtualshareholdermeeting.com/DFTX2026 on June 11, 2026 at 10:00 a.m. Eastern Time. To participate, vote or submit questions during the Annual Meeting, shareholders or their proxyholders must log on to the virtual meeting platform by entering the 16-digit control number included on your proxy card, Notice of Internet Availability of Proxy Materials (“Notice”) or voting instruction form. Online access to the Annual Meeting will open approximately 15 minutes prior to the start of the virtual meeting.

The Annual Meeting and any or all adjournments or postponements thereof will be held for the following purposes:

(1) To elect Carol A. Vallone, Andreas Krebs, Dr. Suzanne Bruhn, Dr. Roger Crystal, David Gryska, Roger Adsett and Robert Barrow to the Company’s board of directors (the “Board of Directors” or the “Board”) to hold office until the 2027 annual general meeting of shareholders (“Proposal No. 1”);

(2) To appoint KPMG LLP (“KPMG”) as independent registered public accounting firm (auditor) for the Company until the 2027 annual general meeting of shareholders (“Proposal No. 2”);

(3) To consider and, if deemed advisable, approve the amendment to the Definium Therapeutics, Inc. 2025 Equity Incentive Plan (the “2025 Equity Incentive Plan”) to increase the number of common shares available for issuance under the 2025 Equity Incentive Plan (“Proposal No. 3”) by 5,000,000 common shares; and

(4) To conduct any other business properly brought before the Annual Meeting and any adjournment or postponement thereof.

These items of business are more fully described in the proxy statement accompanying this Notice of Annual General and Special Meeting of Shareholders. The Annual Meeting will be held in a virtual format to enable greater participation by shareholders. At the Annual Meeting, all shareholders, regardless of geographic location and equity ownership, will have an equal opportunity to participate. Please attend the Annual Meeting at www.virtualshareholdermeeting.com/DFTX2026. Audio can be accessed via a phone, tablet or computer.

The record date for the Annual Meeting is April 15, 2026 (the “Record Date”). Only shareholders of record as of the close of business on that date may vote at the Annual Meeting or any adjournment or postponement thereof.

You may vote by submitting your proxy via the Internet, by telephone, or by mail by following the instructions on the proxy card or Notice by June 10, 2026 at 11:59 p.m. Eastern Time. If you are a beneficial owner of shares registered in the name of a broker, bank or other nominee, you should have received a voting instruction form with these proxy materials from that organization rather than from Definium. Simply complete and mail the voting instruction form in accordance with the instructions in that form to ensure that your vote is counted. Alternatively, you may vote by telephone or over the Internet by following the instructions provided by your broker, bank or other nominee. Beneficial owners should provide their voting instructions to their broker, bank or other nominee sufficiently in advance of the Annual Meeting and in accordance with the voting instructions provided by their broker, bank or other nominee.

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Although not part of the proxy statement accompanying this Notice of Annual General and Special Meeting of Shareholders, we are also making available our 2025 Annual Report on Form 10-K, which includes our financial statements prepared in accordance with U.S. GAAP for the fiscal year ended December 31, 2025 (the “Annual Report”). The proxy statement, the proxy card and the Annual Report are first being made available online to shareholders beginning on or about April 27, 2026.

Important Notice Regarding the Availability of Proxy Materials for the

Annual Meeting to be Held on June 11, 2026 at 10:00 a.m. Eastern Time:

The proxy statement, the proxy card and the Annual Report are available at: www.proxyvote.com

You may also request paper copies of materials by the following methods:
Completing a request at www.proxyvote.com; By telephone at 1-800-579-1639; or
By e-mailing sendmaterial@proxyvote.com and include 16-digit control number in the subject line.

By Order of the Board of Directors,

Robert Barrow
Chief Executive Officer

New York, New York
April 27, 2026

     Your vote is very important to us. Whether or not you expect to attend the Annual Meeting, please complete, date, sign and return the enclosed proxy card or voting instruction form, or vote over the telephone or the Internet as instructed in these materials, as promptly as possible in order to ensure your representation at the Annual Meeting. Shareholders who attend the Annual Meeting should follow the instructions found at www.virtualshareholdermeeting.com/DFTX2026 to vote during the Annual Meeting.

    

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TABLE OF CONTENTS


PROXY STATEMENT SUMMARY	1
QUESTIONS AND ANSWERS ABOUT THE ANNUAL GENERAL AND SPECIAL MEETING	7
OVERVIEW OF PROPOSALS	15
PROPOSAL NO. 1 ELECTION OF DIRECTORS	16
INFORMATION REGARDING THE BOARD OF DIRECTORS AND CORPORATE GOVERNANCE	23
PROPOSAL NO. 2 APPOINTMENT OF AUDITOR	32
PROPOSAL NO. 3 AMENDMENT TO 2025 EQUITY INCENTIVE PLAN	34
EXECUTIVE OFFICERS OF THE COMPANY	43
SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT	45
EXECUTIVE COMPENSATION	48
DIRECTOR COMPENSATION	64
SECURITIES AUTHORIZED FOR ISSUANCE UNDER EQUITY COMPENSATION PLANS	67
INDEBTEDNESS OF DIRECTORS AND EXECUTIVE OFFICERS	67
INTEREST OF INFORMED PERSONS IN MATERIAL TRANSACTIONS	68
INTEREST OF CERTAIN PERSONS OR COMPANIES IN MATTERS TO BE ACTED UPON	70
HOUSEHOLDING OF PROXY MATERIALS	70
ADDITIONAL INFORMATION	70
OTHER MATTERS	70
ANNEX A – CORPORATE GOVERNANCE GUIDELINES
ANNEX B – AMENDMENT NO. 1 TO DEFINIUM THERAPEUTICS, INC. 2025 EQUITY INCENTIVE PLAN

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PROXY STATEMENT SUMMARY

This summary highlights certain information related to topics discussed in this proxy statement (this “Proxy Statement”). This summary does not contain all of the information you should consider, and you should read this entire Proxy Statement carefully before voting.

Virtual Annual Meeting Information


Date:		June 11, 2026
Time:		10:00 a.m. Eastern Time
Location:		Online at www.virtualshareholdermeeting.com/DFTX2026
Record Date:		April 15, 2026

How to Vote*


By Internet (prior to the Annual Meeting)	By Telephone	By Mailing your Proxy Card	By Internet (during the Annual Meeting)

Visit 24/7 www.proxyvote.com	Dial toll-free 24/7 1-800-690-6903	Cast your ballot, sign your proxy card and send by free post	Vote during the live webcast of the Annual Meeting
Visit www.proxyvote.com and have available the 16-digit control number included on your proxy card or Notice. Your internet vote must be received by June 10, 2026 at 11:59 p.m. Eastern Time.	Dial toll-free 1-800-690-6903 using a touch-tone phone and follow the recorded instructions. You will be asked to provide the 16-digit control number included on your proxy card or Notice. Your telephone vote must be received by June 10, 2026 at 11:59 p.m. Eastern Time.	Complete, sign and date the enclosed proxy card by June 10, 2026 at 11:59 p.m. Eastern Time in the envelope provided. If you return your signed proxy card to us before such deadline, we will vote your shares as you direct.	You may vote during the Annual Meeting by going to www.virtualshare holdermeeting.com/DFTX2026 and providing the 16-digit control number included on your proxy card or Notice.

* If you are a beneficial owner of shares registered in the name of a broker, bank, or other nominee, you should have received a voting instruction form with these proxy materials from that organization rather than from Definium. Simply complete and mail the voting instruction form in accordance with the instructions in that form to ensure that your vote is counted. Alternatively, you may vote by telephone or over the Internet by following the instructions provided by your broker, bank or other nominee. Beneficial owners should provide their voting instructions to their broker, bank or nominee sufficiently in advance of the Annual Meeting and in accordance with the voting instructions provided by their broker, bank or other nominee. You are also invited to attend the Annual Meeting by visiting www.virtualshareholdermeeting.com/DFTX2026 and entering the 16-digit control number found on your voting instruction form and voting instructions received from your broker, bank or other nominee. If you did not receive a 16-digit control number, please contact your broker, bank or other nominee as soon as possible, so that you can be provided with a control number and gain access to the Annual Meeting.

Online access to the Annual Meeting will open approximately 15 minutes prior to the start of the virtual meeting. We recommend that you visit www.virtualshareholdermeeting.com/DFTX2026 and log in with your

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16-digit control number prior to the start time of 10:00 a.m. Eastern Time to ensure you are fully logged in when the Annual Meeting begins. If you attend the Annual Meeting, you may vote your shares electronically during the Annual Meeting even if you have previously returned your proxy card or completed your proxy by phone or on the Internet.

A summary of the information you need to participate in the Annual Meeting online is provided below.

• Any shareholder and duly appointed proxyholder as of the Record Date will be entitled to attend, participate and vote at the Annual Meeting via webcast at www.virtualshareholdermeeting.com/DFTX2026.

• To enter the Annual Meeting, please have the 16-digit control number available, which is included on your proxy card, Notice or voting instruction form. If your common shares are held of record by a broker, bank or other nominee and you did not receive a 16-digit control number, please contact your broker, bank or other nominee as soon as possible, so that you can be provided with a control number and gain access to the Annual Meeting.

• You may vote and submit questions during the Annual Meeting by following the instructions on the log-in page for the webcast at www.virtualshareholdermeeting.com/DFTX2026.

• If you encounter technical difficulties or trouble accessing the live webcast of the Annual Meeting or other technical issues during the Annual Meeting, please call the technical support number that will be posted on the log-in page for the Annual Meeting for assistance.

Cast Your Vote Right Away


Proposals	More Information	Board of Directors Recommendation
Proposal 1: To elect Carol A. Vallone, Andreas Krebs, Dr. Suzanne Bruhn, Dr. Roger Crystal, David Gryska, Roger Adsett and Robert Barrow to the Company’s Board to hold office until the 2027 annual general meeting of shareholders	Page 16	FOR each nominee
Proposal 2: To appoint KPMG as independent registered public accounting firm (auditor) for the Company until the 2027 annual general meeting of shareholders	Page 32	FOR
Proposal 3: To approve the amendment to the 2025 Equity Incentive Plan to increase the number of common shares available for issuance under the 2025 Equity Incentive Plan by 5,000,000 common shares	Page 34	FOR

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Governance Highlights

We are committed to maintaining strong corporate governance practices and continuing to build on our success and long-term shareholder value. The highlights of our corporate governance practices include the following:

SEC Form DEF 14A filed by Definium Therapeutics Inc.