[SCHEDULE 13G/A] Definium Therapeutics, Inc. Amended Passive Investment Disclosure
Commodore Capital reports 1.8% stake in Definium
Definium Therapeutics, Inc. investor Commodore Capital and related filers report beneficial ownership of 2,410,000 Common Shares, including shares underlying a pre-funded warrant, as of June 30, 2026.
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Definium Therapeutics, Inc. investor Commodore Capital and related filers report beneficial ownership of 2,410,000 Common Shares, including shares underlying a pre-funded warrant, as of June 30, 2026. This represents 1.8% of the outstanding Common Shares of Definium Therapeutics, Inc.
The position consists of 2,000,000 Common Shares and 410,000 Common Shares that each filer has the right to acquire through exercise of a pre-funded warrant. Voting and dispositive power over all 2,410,000 shares is reported on a shared basis, with no sole voting or dispositive power. The ownership percentage is based on 134,365,950 Common Shares outstanding as of June 30, 2026, plus the 410,000 shares issuable upon exercise of the pre-funded warrant.
Key Figures
Beneficial ownership:2,410,000 Common SharesOwnership percentage:1.8%Shares outstanding baseline:134,365,950 Common Shares+3 more
6 metrics
Beneficial ownership2,410,000 Common SharesAggregate Common Shares beneficially owned by all filers as of June 30, 2026
Ownership percentage1.8%Percent of Definium Therapeutics Common Shares beneficially owned by the filers
Shares outstanding baseline134,365,950 Common SharesShares outstanding as of June 30, 2026 used to calculate ownership percentage
Common Shares held2,000,000 Common SharesPortion of the filers’ position in already-issued Common Shares
Shares via pre-funded warrant410,000 Common SharesShares the filers may acquire upon exercise of a pre-funded warrant
Shared voting power2,410,000 Common SharesShares over which the filers have shared power to vote
"the Firm may be deemed to beneficially own an aggregate of 2,410,000 shares"
Beneficially own means having the economic rights and risks of a security—such as the right to receive dividends, sell the shares, or profit from price changes—whether or not your name appears on the official share register. Think of it like renting a car: you use it and reap the benefits even if the title lists someone else. Investors care because beneficial ownership determines who truly controls value, must be disclosed under securities rules, and can signal potential influence or trading activity that affects a stock’s price.
pre-funded warrantfinancial
"410,000 shares of Common Shares each Filer has the right to acquire through the exercise of a pre-funded warrant"
A pre-funded warrant is a financial instrument that gives the holder the right to buy shares of a company's stock at a set price, with most of the purchase cost already paid upfront. It functions like a nearly fully paid option, allowing investors to secure shares quickly while minimizing the amount of additional money they need to invest later. This helps investors gain ownership rights efficiently, often used to avoid certain regulatory restrictions or to prepare for future stock purchases.
shared voting powerfinancial
"Shared Voting Power 2,410,000.00"
Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.
shared dispositive powerfinancial
"Shared Dispositive Power 2,410,000.00"
investment managerfinancial
"The Firm is the investment manager to Commodore Master."
FAQ
AI-generated questions and answers. How Rhea-AI works. Not financial advice.
What percentage of Definium Therapeutics (DFTX) does Commodore Capital report owning?
Commodore Capital and related filers report beneficial ownership of 1.8% of Definium Therapeutics’ Common Shares. This 1.8% is calculated on 134,365,950 shares outstanding plus 410,000 shares issuable upon exercise of a pre-funded warrant.
How many Definium Therapeutics (DFTX) shares does Commodore Capital beneficially own?
The filers report beneficial ownership of 2,410,000 Common Shares of Definium Therapeutics. This consists of 2,000,000 existing shares and 410,000 shares that may be acquired through exercising a pre-funded warrant held by the filers.
What type of securities linked to Definium Therapeutics (DFTX) does Commodore Capital hold?
The reported position includes Common Shares and a pre-funded warrant exercisable into 410,000 Common Shares. In total, the filers may be deemed to beneficially own 2,410,000 Common Shares of Definium Therapeutics, Inc.
How is voting power over Definium Therapeutics (DFTX) shares allocated for Commodore Capital?
The filers report 0 sole voting power and 2,410,000 shares of shared voting power. They likewise report 0 sole dispositive power and 2,410,000 shares of shared dispositive power over Definium Therapeutics Common Shares.
Which entities and individuals are included as filers in this Definium Therapeutics (DFTX) ownership report?
The report is filed by Commodore Capital LP, Commodore Capital Master LP, and individuals Robert Egen Atkinson and Michael Kramarz. Commodore Capital LP is investment manager to Commodore Capital Master LP and its managing partners exercise investment discretion.
What is the share count used to calculate Commodore Capital’s ownership in Definium Therapeutics (DFTX)?
The ownership percentage is based on 134,365,950 Common Shares outstanding as of June 30, 2026, plus 410,000 additional shares that the filers may acquire upon exercise of a pre-funded warrant held in Definium Therapeutics, Inc.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 3)
Definium Therapeutics, Inc.
(Name of Issuer)
Common Shares, no par value per share
(Title of Class of Securities)
24477V105
(CUSIP Number)
06/30/2026
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
schemaVersion:
SCHEDULE 13G
CUSIP Number(s):
24477V105
1
Names of Reporting Persons
Commodore Capital LP
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
2,410,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,410,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,410,000.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
1.8 %
12
Type of Reporting Person (See Instructions)
IA, PN
SCHEDULE 13G
CUSIP Number(s):
24477V105
1
Names of Reporting Persons
Commodore Capital Master LP
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
CAYMAN ISLANDS
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
2,410,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,410,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,410,000.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
1.8 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP Number(s):
24477V105
1
Names of Reporting Persons
Robert Egen Atkinson
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
2,410,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,410,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,410,000.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
1.8 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
CUSIP Number(s):
24477V105
1
Names of Reporting Persons
Michael Kramarz
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
2,410,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,410,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,410,000.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
1.8 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Definium Therapeutics, Inc.
(b)
Address of issuer's principal executive offices:
One World Trade Center, Suite 8500, New York, NEW YORK, 10007.
Item 2.
(a)
Name of person filing:
Commodore Capital LP
Commodore Capital Master LP
Robert Egen Atkinson
Michael Kramarz
Each a "Filer."
(b)
Address or principal business office or, if none, residence:
The address for Commodore Capital LP, Robert Egen Atkinson, and Michael Kramarz is 444 Madison Avenue, Floor 35, New York, NY 10022.
The address for Commodore Capital Master LP is c/o Maples Corporate Services Limited, Ugland House, South Church Street, PO Box 309, Grand Cayman KY1-1104, Cayman Islands.
(c)
Citizenship:
See Item 4 of the cover page for each Filer.
(d)
Title of class of securities:
Common Shares, no par value per share
(e)
CUSIP No.:
24477V105
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.
Ownership
(a)
Amount beneficially owned:
See Item 9 of the cover page for each Filer.
This report on Schedule 13G is being filed by Commodore Capital LP (the "Firm"), Commodore Capital Master LP ("Commodore Master"), Michael Kramarz, and Robert Egen Atkinson. The Firm is the investment manager to Commodore Master. As of June 30, 2026, the Firm may be deemed to beneficially own an aggregate of 2,410,000 shares of Common Shares, no par value per share (the "Common Shares"), consisting of (i) 2,000,000 shares of Common Shares and (ii) 410,000 shares of Common Shares each Filer has the right to acquire through the exercise of a pre-funded warrant ("Pre-Funded Warrant") of Definium Therapeutics, Inc. (the "Issuer"). The Firm, as the investment manager to Commodore Master, may be deemed to beneficially own these securities. Michael Kramarz and Robert Egen Atkinson are the managing partners of the Firm and exercise investment discretion with respect to these securities. Ownership percentages are based on 134,365,950 shares of the Issuer's Common Shares outstanding as of June 30, 2026 in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 6, 2026, plus 410,000 shares of Common Shares which the Filers may acquire upon the exercise of the Pre-Funded Warrant.
(b)
Percent of class:
See Item 11 of the cover page for each Filer.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
See Item 5 of the cover page for each Filer.
(ii) Shared power to vote or to direct the vote:
See Item 6 of the cover page for each Filer.
(iii) Sole power to dispose or to direct the disposition of:
See Item 7 of the cover page for each Filer.
(iv) Shared power to dispose or to direct the disposition of:
See Item 8 of the cover page for each Filer.
Item 5.
Ownership of 5 Percent or Less of a Class.
Ownership of 5 percent or less of a class
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
Not Applicable
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
