Definium Therapeutics officer proposes $1.16M share sale

The notice also lists two earlier sales: 19,023 shares for $718,144.88 on September 3 and 29,208 shares for $1,230,533.04 on June 25, 2026.

Available on EDGAR 09/25/2026 - 04:17 PM EDT Accepted by SEC EDGAR 09/25/2026 - 04:06 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Definium Therapeutics, Inc. reports that Robert B. Barrow, identified as an officer and director, gave notice of a proposed sale of 31,550 common shares through Morgan Stanley Smith Barney LLC, with an approximate sale date of September 25, 2026, on NASDAQ. The notice lists an aggregate market value of $1,158,831.50 and identifies the shares as restricted stock vesting under a registered plan for services rendered. It also lists earlier sales by Barrow of 19,023 shares for $718,144.88 on September 3, 2026, and 29,208 shares for $1,230,533.04 on June 25, 2026.

Key Figures

Common shares proposed for sale: 31,550 shares Aggregate market value: $1,158,831.50 Common shares sold: 19,023 shares +3 more

6 metrics

Common shares proposed for sale 31,550 shares Approximate sale date September 25, 2026

Aggregate market value $1,158,831.50 Proposed sale of common shares

Common shares sold 19,023 shares September 3, 2026; sale value $718,144.88

Sale value $718,144.88 19,023 common shares sold on September 3, 2026

Common shares sold 29,208 shares June 25, 2026; sale value $1,230,533.04

Sale value $1,230,533.04 29,208 common shares sold on June 25, 2026

Key Terms

Rule 144, restricted stock vesting, aggregate market value

3 terms

Rule 144 regulatory

"definition of "person" in paragraph (a) of Rule 144"

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

restricted stock vesting financial

"Restricted Stock Vesting Under a Registered Plan"

Restricted stock vesting is the timetable and conditions under which shares granted to employees or insiders become fully owned and can be sold, typically requiring continued work or meeting performance goals. It matters to investors because large blocks of shares can become tradable at once, which can change share supply and price, and because vesting aligns insiders’ incentives with the company’s long‑term performance—think of it like a timed unlock that both rewards and locks in key people.

aggregate market value financial

"Aggregate market value"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

FAQ

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

How many DFTX shares does Robert B. Barrow plan to sell?

Robert B. Barrow's notice lists a proposed sale of 31,550 common shares, with an aggregate market value of $1,158,831.50 and an approximate sale date of September 25, 2026, through Morgan Stanley Smith Barney LLC on NASDAQ.

What previous DFTX stock sales did Robert B. Barrow report?

The notice lists 19,023 common shares sold on September 3, 2026, for $718,144.88, and 29,208 common shares sold on June 25, 2026, for $1,230,533.04.

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

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Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001897557
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	DEFINIUM THERAPEUTICS, INC.
SEC File Number	001-40360
Address of Issuer	ONE WORLD TRADE CENTER SUITE 8500 NEW YORK NEW YORK 10007
Phone	212-220-6633
Name of Person for Whose Account the Securities are To Be Sold	ROBERT B BARROW
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer
Relationship to Issuer	Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	31550	1158831.50	134366950	09/25/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	09/25/2026	Restricted Stock Vesting Under a Registered Plan	Issuer			31550	09/25/2026	Services Rendered

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
ROBERT B BARROW ONE WORLD TRADE CENTER SUITE 8500 NEW YORK NY 10007	Common	09/03/2026	19023	718144.88
ROBERT B BARROW ONE WORLD TRADE CENTER SUITE 8500 NEW YORK NY 10007	Common	06/25/2026	29208	1230533.04

144: Remarks and Signature

Remarks
Date of Notice	09/25/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Robert Barrow
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)