Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 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 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * Vida Ventures II, LLC 2. Issuer Name and Ticker or Trading Symbol Aktis Oncology, Inc. [AKTS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O VIDA VENTURES ADVISORS, LLC, 10100 SANTA MONICA BOULEVARD, SUITE 1500 3. Date of Earliest Transaction (Month/Day/Year) 01/12/2026 (Street) LOS ANGELES, CA 90067 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) 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 Stock 01/12/2026 C(1) 4,859,370 A (1) 4,859,370 I See Footnote(2) Common Stock 01/12/2026 P 812,455 A $18 5,671,825 I See Footnote(2) Common Stock 01/12/2026 C(1) 134,842 A (1) 134,842 I See Footnote(3) Common Stock 01/12/2026 P 22,545 A $18 157,387 I See Footnote(3)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 Underlying Securities (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 of Derivative Security: 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

Series A Redeemable Convertible Preferred Stock

(4)

01/12/2026

C

14,838,250

(4)

(4)

Common Stock

3,900,284

$ 0

0

I

See Footnote(2)

Series A Redeemable Convertible Preferred Stock

(4)

01/12/2026

C

411,750

(4)

(4)

Common Stock

108,229

$ 0

0

I

See Footnote(3)

Series B Redeemable Convertible Preferred Stock

(5)

01/12/2026

C

3,648,750

(5)

(5)

Common Stock

959,086

$ 0

0

I

See Footnote(2)

Series B Redeemable Convertible Preferred Stock

(5)

01/12/2026

C

101,250

(5)

(5)

Common Stock

26,613

$ 0

0

I

See Footnote(3)

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Vida Ventures II, LLC C/O VIDA VENTURES ADVISORS, LLC 10100 SANTA MONICA BOULEVARD, SUITE 1500 LOS ANGELES, CA 90067		X
VIDA VENTURES II-A, LLC 10100 SANTA MONICA BOULEVARD., SUITE 1500 LOS ANGELES, CA 90067		X

Signatures

VIDA VENTURES II, LLC, By: VV Manager II, LLC, its Manager, By: /s/ Jean-Philippe Kouakou-Zebouah, Authorized Signatory		01/12/2026
**Signature of Reporting Person		Date
VIDA VENTURES II-A, LLC, By: VV Manager II, LLC, its Manager, By: /s/ Jean-Philippe Kouakou-Zebouah, Authorized Signatory		01/12/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	Represents shares of the Issuer's Common Stock received upon conversion of shares of the Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock on a 3.8044-for-1 basis without payment of additional consideration.
(2)	These shares are held by Vida Ventures II, LLC ("VV II"). VV Manager II, LLC ("VVM II") is the manager of VV II and may be deemed to have voting, investment and dispositive power with respect to the shares held by VV II. Arie Belldegrun, Fred Cohen, and Leonard Potter, the members of the management committee of VVM II, along with the other members of the investment committee of VVM II, Rajul Jain, Joshua Kazam, and Helen Kim, a member of the Issuer's board of directors, may be deemed to share voting, investment and dispositive power over the shares held by VV II and each such person disclaims beneficial ownership of the securities except to the extent of such person's pecuniary interest therein.
(3)	These shares are held by Vida Ventures II-A, LLC ("VV II-A"). VVM II is the manager of VV II-A and may be deemed to have voting, investment and dispositive power with respect to the shares held by VV II-A. Arie Belldegrun, Fred Cohen, and Leonard Potter, the members of the management committee of VVM II, along with the other members of the investment committee of VVM II, Rajul Jain, Joshua Kazam, and Helen Kim, a member of the Issuer's board of directors, may be deemed to share voting, investment and dispositive power over the shares held by VV II-A and each such person disclaims beneficial ownership of the securities except to the extent of such person's pecuniary interest therein.
(4)	The Series A Redeemable Convertible Preferred Stock had no expiration date and automatically converted into the Issuer's Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the Issuer's initial public offering of its Common Stock without payment of additional consideration.
(5)	The Series B Redeemable Convertible Preferred Stock had no expiration date and automatically converted into the Issuer's Common Stock on a 3.8044-for-1 basis immediately prior to the closing of the Issuer's initial public offering of its Common Stock without payment of additional consideration.

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