Definium CLO granted 62,500 performance-based shares

Sullivan Mark reported acquisition or exercise transactions in this Form 4 filing.

Rhea-AI Filing Summary

Sullivan Mark reported acquisition or exercise transactions in this Form 4 filing.

Definium Therapeutics Chief Legal Officer Mark Sullivan received 62,500 common shares as a performance-based equity award. The shares were granted at no purchase price and increase his direct holdings to 333,579 common shares. This tranche stems from performance share units granted effective March 12, 2025 and remains subject to vesting based on continued employment through March 12, 2028 and achievement of specified clinical and regulatory milestones.

Insider Trade Summary

Grant/Award: 62,500 shares

Grant/Award 1 txn

Insider Sullivan Mark

Role Chief Legal Officer

Type	Security	Shares	Price	Value
Grant/Award	Common Shares	62,500	$0.00	$0.00

Holdings After Transaction: Common Shares — 333,579 shares (Direct)

Footnotes (1)

1. F1. The common shares represent the first tranche of performance share units granted effective March 12, 2025, and remain subject to vesting based on the Reporting Person's continued employment through March 12, 2028. Each performance share unit represented a contingent right to receive one common share based on, and subject to, the achievement of certain clinical and regulatory milestones set forth in the Performance Share Unit Award Agreement.

Key Figures

Shares granted: 62,500 shares Grant price: $0.00 per share Total holdings after grant: 333,579 shares +2 more

5 metrics

Shares granted 62,500 shares Common shares acquired as award on June 22, 2026

Grant price $0.00 per share Price per common share in the award

Total holdings after grant 333,579 shares Direct common share ownership after transaction

PSU grant effective date March 12, 2025 Effective date of underlying performance share unit grant

Vesting employment date March 12, 2028 Continued employment required through this date

Key Terms

performance share units, vesting, contingent right, clinical and regulatory milestones

4 terms

performance share units financial

"The common shares represent the first tranche of performance share units granted effective March 12, 2025"

Performance share units are a type of company stock award given to employees that depend on the company meeting specific goals or targets. If these goals are achieved, the employee receives shares or the value of shares; if not, they may receive little or no compensation. This aligns employees’ interests with the company's success and encourages performance that benefits investors.

vesting financial

"and remain subject to vesting based on the Reporting Person's continued employment through March 12, 2028"

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

contingent right financial

"Each performance share unit represented a contingent right to receive one common share"

clinical and regulatory milestones financial

"subject to, the achievement of certain clinical and regulatory milestones set forth in the Performance Share Unit Award Agreement"

Clinical and regulatory milestones are the key steps a medical product must clear as it is tested on patients and reviewed by government health authorities, such as completing major clinical trials, filing safety and effectiveness data, or receiving marketing approval. Investors watch these checkpoints like milestones on a roadmap because each one sharply changes the odds that a product will reach patients and generate revenue, much like a car passing inspection before it can be sold.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Definium Therapeutics (DFTX) disclose in this Form 4 for Mark Sullivan?

Definium Therapeutics reported that Chief Legal Officer Mark Sullivan received 62,500 common shares as a performance-based equity award, granted at no purchase price, increasing his direct holdings to 333,579 shares, subject to vesting and milestone conditions.

How many Definium Therapeutics (DFTX) shares did Mark Sullivan acquire?

Mark Sullivan acquired 62,500 common shares of Definium Therapeutics. These represent the first tranche from a performance share unit grant and are subject to vesting conditions tied to his continued employment and specified clinical and regulatory milestones.

What are Mark Sullivan’s total Definium Therapeutics (DFTX) holdings after this grant?

After the grant, Mark Sullivan directly holds 333,579 common shares of Definium Therapeutics. This total includes the newly awarded 62,500 shares that are linked to performance criteria and continued employment-based vesting requirements through March 12, 2028.

Are the new Definium Therapeutics (DFTX) shares fully vested for Mark Sullivan?

No, the 62,500 common shares remain subject to vesting. They derive from performance share units that require Mark Sullivan’s continued employment through March 12, 2028 and achievement of specified clinical and regulatory milestones before fully vesting.

What is the origin of the 62,500 Definium Therapeutics (DFTX) shares granted to Mark Sullivan?

The 62,500 shares represent the first tranche of performance share units granted effective March 12, 2025. Each unit provided a contingent right to receive one common share upon satisfaction of defined clinical and regulatory milestones set in the award agreement.

Did Mark Sullivan pay for the new Definium Therapeutics (DFTX) shares?

No, the 62,500 common shares were granted at a per-share price of $0.00. They are part of a performance-based equity compensation arrangement rather than an open-market purchase, and remain subject to vesting and milestone achievement conditions.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 06/22/2026 - 09:45 AM EDT Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Sullivan Mark

(Last) (First) (Middle)

C/O DEFINIUM THERAPEUTICS, INC.

ONE WORLD TRADE CENTER, SUITE 8500

(Street)

NEW YORK NEW YORK 10007

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Definium Therapeutics, Inc. [ DFTX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Legal Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/22/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Shares	06/22/2026		A		62,500(1)	A	$0.00	333,579	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. The common shares represent the first tranche of performance share units granted effective March 12, 2025, and remain subject to vesting based on the Reporting Person's continued employment through March 12, 2028. Each performance share unit represented a contingent right to receive one common share based on, and subject to, the achievement of certain clinical and regulatory milestones set forth in the Performance Share Unit Award Agreement.

	/s/ Mark Sullivan	06/22/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)