Definium Therapeutics (DFTX) CMO receives 150,000 RSUs vesting from 2026

Rhea-AI Filing Summary

Definium Therapeutics, Inc. Chief Medical Officer Dan Karlin reported an award of 150,000 common shares of the company on February 3, 2026. These are structured as restricted stock units, granted at a price of $0.00 per share, increasing his direct holdings to 575,025 shares.

The RSUs vest in 16 equal quarterly installments starting on June 1, 2026. Each RSU converts into one common share if he continues providing service to Definium Therapeutics on each vesting date, tying the value of this grant to his ongoing tenure.

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^*

Karlin Daniel

(Last) (First) (Middle)

C/O DEFINIUM THERAPEUTICS, INC.

ONE WORLD TRADE CENTER, SUITE 8500

(Street)

NEW YORK NY 10007

(City) (State) (Zip)

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 Medical Officer

3. Date of Earliest Transaction (Month/Day/Year)
02/03/2026

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

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

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

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	02/03/2026		A		150,000(1)	A	$0.00	575,025	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. These shares represent restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one common share of the Issuer. The RSUs vest in 16 equal quarterly installments beginning on June 1, 2026, subject to the Reporting Person providing continuous service to the Issuer on each such vesting date.

	/s/Mark Sullivan, Attorney-in-Fact for Dan Karlin	02/05/2026
	** 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.

FAQ

What did DFTX Chief Medical Officer Dan Karlin report in this Form 4?

Dan Karlin reported an award of 150,000 common shares of Definium Therapeutics as restricted stock units. The grant was made at $0.00 per share and increased his directly held beneficial ownership to 575,025 common shares in total.

How do the 150,000 RSUs granted to DFTX’s CMO vest?

The 150,000 restricted stock units vest in 16 equal quarterly installments, beginning on June 1, 2026. Each vesting date requires Dan Karlin to continue providing service to Definium Therapeutics, aligning the equity award with his ongoing employment.

What does each RSU granted to the DFTX CMO represent?

Each restricted stock unit represents a contingent right to receive one common share of Definium Therapeutics. The RSUs only convert into common shares as they vest on scheduled dates, assuming the CMO continues to provide service to the company.

What is Dan Karlin’s total share ownership in DFTX after this transaction?

After the RSU grant, Dan Karlin beneficially owns 575,025 common shares of Definium Therapeutics directly. This total reflects the newly awarded 150,000 RSUs, which will convert into common shares over time as they vest quarterly.

Was any cash paid for the 150,000 RSUs reported by DFTX’s CMO?

The 150,000 common shares underlying the restricted stock units were granted at a price of $0.00 per share. This indicates an equity compensation award, with value realized as the RSUs vest into common shares over the specified schedule.