EcoR1 Capital, LLC - 08 Jan 2026 Form 3 Insider Report for Aktis Oncology, Inc. (AKTS)

Role: Director, 10%+ Owner
Signature: /s/ Oleg Nodelman, Manager of EcoR1 Capital, LLC
Issuer symbol: AKTS
Transactions as of: 08 Jan 2026
Net transactions value: $0
Form type: 3
Filing time: 08 Jan 2026, 20:49:58 UTC
Previous filing: 30 Jul 2025
Next filing: 12 Jan 2026
SEC: View on sec.gov

Reporting Owners (2)

Name	Relationship	Address	Signature	Signature date	CIK
EcoR1 Capital, LLC	Director, 10%+ Owner	357 TEHAMA STREET #3, SAN FRANCISCO	/s/ Oleg Nodelman, Manager of EcoR1 Capital, LLC	08 Jan 2026	0001587114
NODELMAN OLEG	Director, 10%+ Owner	357 TEHAMA STREET #3, SAN FRANCISCO	/s/ Oleg Nodelman, Manager of EcoR1 Capital, LLC	08 Jan 2026	0001454385

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
holding	AKTS	Series A Redeemable Convertible Preferred Stock	08 Jan 2026	Common Stock	2,605,878		See note	F1, F2, F3
holding	AKTS	Series A Redeemable Convertible Preferred Stock	08 Jan 2026	Common Stock	262,142		See note	F1, F2, F4
holding	AKTS	Series A Redeemable Convertible Preferred Stock	08 Jan 2026	Common Stock	128,506		See note	F1, F2, F5
holding	AKTS	Series B Redeemable Convertible Preferred Stock	08 Jan 2026	Common Stock	630,191		See note	F1, F2, F3
holding	AKTS	Series B Redeemable Convertible Preferred Stock	08 Jan 2026	Common Stock	26,942		See note	F1, F2, F4
holding	AKTS	Director Stock Option (Right to Acquire)	08 Jan 2026	Common Stock	37,866	$18.00	Direct	F6, F7

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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.
F2	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.
F3	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.
F4	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.
F5	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.
F6	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.
F7	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.