SEC FORM 3

SEC FORM 3 SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF 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^*

EcoR1 Capital, LLC

(Last)

(First)

(Middle)

357 TEHAMA STREET #3

(Street)

SAN FRANCISCO

94103

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
01/08/2026

3. Issuer Name and Ticker or Trading Symbol
Aktis Oncology, Inc. [ AKTS ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

5. If Amendment, Date of 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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Series A Redeemable Convertible Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	2,605,878⁽²⁾	⁽¹⁾	I	See note⁽³⁾
Series A Redeemable Convertible Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	262,142⁽²⁾	⁽¹⁾	I	See note⁽⁴⁾
Series A Redeemable Convertible Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	128,506⁽²⁾	⁽¹⁾	I	See note⁽⁵⁾
Series B Redeemable Convertible Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	630,191⁽²⁾	⁽¹⁾	I	See note⁽³⁾
Series B Redeemable Convertible Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	26,942⁽²⁾	⁽¹⁾	I	See note⁽⁴⁾
Director Stock Option (Right to Acquire)	⁽⁶⁾	01/07/2036	Common Stock	37,866	$18	D⁽⁷⁾

1. Name and Address of Reporting Person^*

EcoR1 Capital, LLC

(Last)

(First)

(Middle)

357 TEHAMA STREET #3

(Street)

SAN FRANCISCO

94103

(City)

(State)

(Zip)

Relationship of Reporting Person(s) to Issuer

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

NODELMAN OLEG

(Last)

(First)

(Middle)

357 TEHAMA STREET #3

(Street)

SAN FRANCISCO

94103

(City)

(State)

(Zip)

Relationship of Reporting Person(s) to Issuer

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. Shares of Series A Redeemable Convertible Preferred Stock and Series B Redeemable Convertible Preferred Stock are convertible into shares of Common Stock at the election of the holder. Each share is immediately exercisable and has no expiration date, but will be automatically converted on a 3.8044-for-1 basis into shares of Common Stock immediately prior to the closing of the initial public offering of the Issuer's Common Stock.

2. Reflects the number of shares of Common Stock issuable after the 1-for-3.8044 reverse stock split which became effective on January 2, 2026.

3. These securities are held by EcoR1 Capital Fund Qualified, L.P. ("Qualified Fund"). EcoR1 Capital, LLC ("EcoR1") may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

4. These securities are held by EcoR1 Capital Fund, L.P. ("Capital Fund"). EcoR1 may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

5. These securities are held by EcoR1 Venture Opportunity Fund, L.P. ("Venture Fund"). EcoR1 may be deemed to indirectly beneficially own them as the investment adviser to and general partner of the fund. Mr. Nodelman may be deemed to indirectly beneficially own them as the control person of EcoR1.

6. 1/36th of the original number of shares subject to the option shall vest in monthly installments from January 8, 2026, subject to Mr. Nodelman's continuous service through each vesting date, inclusive.

7. These securities are beneficially owned solely by Mr. Nodelman.

Remarks:

EcoR1 is the general partner and investment adviser of private funds, including Qualified Fund, Capital Fund and Venture Fund. Mr. Nodelman is a director of the issuer and is the manager and controlling owner of EcoR1. The reporting persons are filing this Form 3 jointly, but not as a group, and each expressly disclaims membership in a group within the meaning of Rule 13d-5(b) under the Securities Exchange Act of 1934. The reporting persons disclaim beneficial ownership of the securities reported herein, except to the extent of their respective pecuniary interests therein.

	/s/ Oleg Nodelman, Manager of EcoR1 Capital, LLC	01/08/2026
	** 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 5 (b)(v).
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SEC Form 3 filed by new insider Ecor1 Capital, Llc