[SCHEDULE 13D/A] Ikena Oncology, Inc. SEC Filing

Rhea-AI Filing Summary

Atlas Venture funds have filed Amendment No. 1 to their Schedule 13D for ImageneBio, Inc. (formerly Ikena Oncology, Nasdaq: IKNA) to report dilution of their holdings after the 1-for-12 reverse stock split and completion of Ikena’s all-stock merger with Inmagene on 25 Jul 2025.

• Collectively, the reporting entities now own 418,179 post-split common shares, equal to 3.6 % of the 11.6 million shares outstanding.
• Breakdown: Fund X 241,800 shares (2.1 %), Fund XI 103,494 shares (0.9 %), Opportunity Fund I 72,885 shares (0.6 %).
• All voting and dispositive powers are shared among the respective limited partnerships and their general partners; no sole voting power is reported.
• The funds ceased to be 5 % beneficial owners on 25 Jul 2025; no purchases or sales occurred in the past 60 days.
• Purpose: administrative update reflecting dilution from the merger and reverse split; Atlas Venture continues to hold the same absolute number of economic shares pre-transaction but a lower percentage.

Atlas Venture disclaims group status among the reporting persons. A joint filing agreement is included as Exhibit 99.1.

Positive

• No insider selling: Atlas Venture did not dispose of any shares, signalling continued support for ImageneBio.
• Merger completion and reverse split finalized, providing corporate clarity after the Inmagene transaction.

Negative

• Ownership dilution: Atlas Venture’s combined stake falls below 5 %, slightly reducing insider alignment.
• Lower reporting threshold: Future 13D filings may cease unless ownership rises again, reducing visibility into a key holder’s changes.

Insights

Financial Analyst

TL;DR – Atlas Venture’s stake falls to 3.6 % due to merger-related dilution; no shares sold, impact on IKNA share supply already known.

The amendment is largely administrative. Atlas Venture’s absolute share count is unchanged, but the completed Inmagene merger and 1-for-12 reverse split expanded the denominator, cutting their ownership below the 5 % 13D threshold. The filing removes a potential overhang concern of insider selling, as none occurred. From a governance lens, the reduced concentration slightly broadens the float, but Atlas remains a meaningful holder. Market impact is likely minimal because the share count change was disclosed in the July 25 reverse-split announcement and already reflected in trading. Overall, neutral for valuation and liquidity.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)

IMAGENEBIO, INC.

(Name of Issuer)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

45175G207

(CUSIP Number)

Ommer Chohan, CFO
300 Technology Square, 8th Floor,
Cambridge, MA, 02139
(857) 201-2700

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

07/25/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 45175G207

1

Name of reporting person

Atlas Venture Fund X, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 241,800.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 241,800.00

11

Aggregate amount beneficially owned by each reporting person

241,800.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

2.1 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP No. 45175G207

1

Name of reporting person

ATLAS VENTURE ASSOCIATES X, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 241,800.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 241,800.00

11

Aggregate amount beneficially owned by each reporting person

241,800.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

2.1 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP No. 45175G207

1

Name of reporting person

Atlas Venture Associates X, LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 241,800.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 241,800.00

11

Aggregate amount beneficially owned by each reporting person

241,800.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

2.1 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP No. 45175G207

1

Name of reporting person

Atlas Venture Fund XI, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 103,494.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 103,494.00

11

Aggregate amount beneficially owned by each reporting person

103,494.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.9 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP No. 45175G207

1

Name of reporting person

Atlas Venture Associates XI, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 103,494.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 103,494.00

11

Aggregate amount beneficially owned by each reporting person

103,494.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.9 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP No. 45175G207

1

Name of reporting person

Atlas Venture Associates XI, LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 103,494.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 103,494.00

11

Aggregate amount beneficially owned by each reporting person

103,494.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.9 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP No. 45175G207

1

Name of reporting person

Atlas Venture Opportunity Fund I, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

WC

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 72,885.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 72,885.00

11

Aggregate amount beneficially owned by each reporting person

72,885.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.6 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP No. 45175G207

1

Name of reporting person

Atlas Venture Associates Opportunity I, L.P.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 72,885.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 72,885.00

11

Aggregate amount beneficially owned by each reporting person

72,885.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.6 %

14

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13D

CUSIP No. 45175G207

1

Name of reporting person

Atlas Venture Associates Opportunity I, LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 72,885.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 72,885.00

11

Aggregate amount beneficially owned by each reporting person

72,885.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0.6 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, $0.001 par value per share
(b)	Name of Issuer: IMAGENEBIO, INC.
(c)	Address of Issuer's Principal Executive Offices: 12526 High Bluff Drive, Suite 345, San Diego, CALIFORNIA , 92130.
Item 1 Comment: Item 1 of the Statement is amended and supplemented as follows: This Amendment No. 1 (this "Amendment No. 1" or this "Schedule 13D/A") amends and supplements the statement on Schedule 13D originally filed with the Securities and Exchange Commission (the "SEC") on February 11, 2022, (as amended, the "Statement") by the Reporting Persons. Unless otherwise defined herein, capitalized terms used in this Amendment No. 1 shall have the meanings ascribed to them in the Statement. Unless amended or supplemented below, the information in the Statement remains unchanged.
Item 4.	Purpose of Transaction
	Item 4 of the Statement is hereby amended and supplemented as follows: On December 23, 2024, Ikena, Insight Merger Sub I, an exempted company with limited liability incorporated and existing under the laws of the Cayman Islands and direct wholly owned subsidiary of Ikena ("Merger Sub I"), Insight Merger Sub II, an exempted company with limited liability incorporated and existing under the laws of the Cayman Islands and direct wholly owned subsidiary of Ikena ("Merger Sub II"), and Inmagene Biopharmaceuticals, an exempted company with limited liability incorporated and existing under the laws of the Cayman Islands (the "Inmagene"), entered into an Agreement and Plan of Merger (the "Merger Agreement"), pursuant to which, among other matters, and subject to the satisfaction or waiver of the conditions set forth in the Merger Agreement, Merger Sub I merged with and into Inmagene, pursuant to which Merger Sub I ceased to exist and was struck off the Register of Companies by the Registrar of Companies in the Cayman Islands (the "Registrar of Companies"), with Inmagene surviving (the "Surviving Entity") such merger as a direct, wholly owned subsidiary of Ikena (the "First Merger"), and immediately after the First Merger, the Surviving Entity merged with and into Merger Sub II, pursuant to which Inmagene ceased to exist and was struck off the Register of Companies by the Registrar of Companies, with Merger Sub II surviving such merger as a direct, wholly owned subsidiary of Ikena (the "Second Merger" and, collectively with the First Merger, as appropriate, the "Merger"). On July 15, 2025, Ikena held its annual meeting of Ikena stockholders at which Ikena's stockholders approved the Merger, along with a reverse stock split of Ikena's common stock to be with the final ratio to be mutually agreed to by Ikena and Inmagene. On July 25, 2025, the reverse stock split was effected at a ratio of 1-for-12, the Merger closed and Ikena changed its name to "ImageneBio, Inc." The Reporting Persons are filing this Amendment No. 1 to report the dilution of their beneficial ownership by virtue of the completion of the Merger.
Item 5.	Interest in Securities of the Issuer
(a)	As of the date hereof, Atlas X is the record owner of 241,800 shares of Common Stock. AVA X LP is the general partner of Atlas X and AVA X LLC is the general partner of AVA X LP. Each of Atlas X, AVA X LP and AVA X LLC has shared voting and dispositive power over the shares held by Atlas X. As such, each of Atlas X, AVA X LP and AVA X LLC may be deemed to beneficially own the shares held by Atlas X. As of the date hereof, Atlas XI is the record owner of 103,494 shares of Common Stock. AVA XI LP is the general partner of Atlas XI and AVA XI LLC is the general partner of AVA XI LP. Each of Atlas XI, AVA XI LP and AVA XI LLC has shared voting and dispositive power over the shares held by Atlas XI. As such, each of Atlas XI, AVA XI LP and AVA XI LLC may be deemed to beneficially own the shares held by Atlas XI. As of the date hereof, AVOF is the record owner of 72,885 shares of Common Stock. AVAO LP is the general partner of AVOF and AVAO LLC is the general partner of AVAO LP. Each of AVOF, AVAO LP and AVAO LLC has shared voting and dispositive power over the shares held by AVOF. As such, each of AVOF, AVAO LP and AVAO LLC may be deemed to beneficially own the shares held by AVOF. Each of the Fund X Reporting Persons, Fund XI Reporting Persons and Opportunity Fund Reporting Persons may be deemed to beneficially own 2.1%, 0.9% and 0.6%, respectively, of the Issuer's outstanding Common Stock, which percentages are calculated based upon approximately 11,600,000 outstanding shares of Common Stock of the Issuer as of July 25, 2025, as reported in the Issuer's Current Report on Form 8-K and filed with the Securities and Exchange Commission on July 25, 2025. Collectively, the Reporting Persons beneficially own an aggregate of 418,179 shares of Common Stock, which represents 3.6% of the Issuer's outstanding Common Stock. The Fund X Reporting Persons, Fund XI Reporting Persons and the Opportunity Fund Reporting Persons are under common control and as a result, the Reporting Persons may be deemed to be members of a group. However, the Reporting Persons disclaim such group membership, and this Schedule 13D shall not be deemed an admission that the Reporting Persons are members of a group for purposes of Section 13 or for any other purposes.
(b)	As of the date hereof, each of Atlas X, AVA X LP and AVA X LLC have shared voting power and shared dispositive power over 241,800 shares of Common Stock. As of the date hereof, each of Atlas XI, AVA XI LP and AVA XI LLC have shared voting power and shared dispositive power over 103,494 shares of Common Stock. As of the date hereof, each of AVOF, AVAO LP and AVAO LLC have shared voting power and shared dispositive power over 72,885 shares of Common Stock.
(c)	None of the Reporting Persons have purchased or sold any shares of Common Stock during the past 60 days.
(d)	No other person is known to have the right to receive or the power to direct the receipt of dividends from, or any proceeds from the sale of, the shares of Common Stock beneficially owned by any of the Reporting Persons.
(e)	The Reporting Persons ceased to be the beneficial owners of more than five percent of the Common Stock on July 25, 2025 by virtue of the closing of the Merger.
Item 7.	Material to be Filed as Exhibits.
	Exhibit 99.1 - Joint Filing Agreement

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.

Atlas Venture Fund X, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	By: Atlas Venture Associates X, L.P., its general partner, By: Atlas Venture Associates X, LLC, its general partner, By: Ommer Chohan, its CFO
Date:	07/29/2025

ATLAS VENTURE ASSOCIATES X, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	By: Atlas Venture Associates X, LLC, its general partner, By: Ommer Chohan, its CFO
Date:	07/29/2025

Atlas Venture Associates X, LLC

Signature:	/s/ Ommer Chohan
Name/Title:	Ommer Chohan, CFO
Date:	07/29/2025

Atlas Venture Fund XI, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	By: Atlas Venture Associates XI, L.P., its general partner, By: Atlas Venture Associates XI, LLC, its general partner, By: Ommer Chohan, its CFO
Date:	07/29/2025

Atlas Venture Associates XI, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	By: Atlas Venture Associates XI, LLC, its general partner, By: Ommer Chohan, its CFO
Date:	07/29/2025

Atlas Venture Associates XI, LLC

Signature:	/s/ Ommer Chohan
Name/Title:	Ommer Chohan, CFO
Date:	07/29/2025

Atlas Venture Opportunity Fund I, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	By: Atlas Venture Associates Opportunity I L.P., its GP, By: Atlas Venture Associates Opportunity I LLC, its GP, By: Ommer Chohan, its CFO
Date:	07/29/2025

Atlas Venture Associates Opportunity I, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	By: Atlas Venture Associates Opportunity I LLC, its general partner, By: Ommer Chohan, its CFO
Date:	07/29/2025

Atlas Venture Associates Opportunity I, LLC

Signature:	/s/ Ommer Chohan
Name/Title:	Ommer Chohan, CFO
Date:	07/29/2025

FAQ

Why did Atlas Venture file an amended Schedule 13D for IKNA?

To report that its percentage ownership fell to 3.6 % after IKNA’s merger with Inmagene and a 1-for-12 reverse split on 25 Jul 2025.

How many IKNA shares does Atlas Venture now own?

Collectively 418,179 shares: Fund X 241,800; Fund XI 103,494; Opportunity Fund I 72,885.

Did Atlas Venture sell any IKNA shares?

No. The filing states no purchases or sales occurred in the past 60 days; dilution alone lowered the percentage.

What is IKNA’s new share count after the merger?

The filing references approximately 11.6 million common shares outstanding as of 25 Jul 2025.

Does Atlas Venture still have voting control over its IKNA shares?

Yes. Each fund and its general partners retain shared voting and dispositive power over their respective shares.